Automatic heat supply control systems. Heat supply management Prospects for the development of the system
Modernization and Automation of Heat Supply System Minsk experiencce
V.A. Sednin, Scientific Consultant, Doctor of Engineering, Professor,
A.A. Gutkovskiy, Chief Engineer, Belorussian National Technicl University, Scientific Research and Innovations Center of Automated Control Systems in heat power industry
keywords: heat supply system, automated control systems, reliability and quality improvement, heat delivery regulation, data archiving
Heat supply of large cities in Belorussia, as in Russia, is provided by cogeneration and district heat supply systems (hereinafter - DHSS), where facilities are combined into a single system. However, often the decisions made on individual elements of complex heat supply systems do not meet the systematic criteria, reliability, controllability and environment protection requirements. Therefore modernization of the heat supply systems and creation of automated process control systems is the most relevant task.
Description:
V.A. Sednin, A.A. Gutkovsky
The heat supply of large cities of Belarus, as in Russia, is provided by heating and district heating systems (hereinafter referred to as DH), the facilities of which are linked into a single scheme. However, decisions made on individual elements of complex heat supply systems often do not meet system criteria, reliability, manageability and environmental friendliness requirements. Therefore, the modernization of heat supply systems and the creation of automated control systems technological processes is the most pressing issue.
V. A. Sednin, scientific consultant, doctor of tech. sciences, professor
A. A. Gutkovsky, Chief Engineer, Belarusian National Technical University, Research and Innovation Center for Automated Control Systems in Heat Power and Industry
Heat supply to large cities of Belarus, as in Russia, is provided by district heating and district heating systems (DH) whose facilities are linked into a single scheme. However, decisions made on individual elements of complex heat supply systems often do not meet system criteria, reliability, manageability and environmental friendliness requirements. Therefore, the modernization of heat supply systems and the creation of automated process control systems is the most urgent task.
Features of district heating systems
Considering the main features of the SDT of Belarus, it can be noted that they are characterized by:
- continuity and inertia of its development;
- territorial distribution, hierarchy, variety of used technical means;
- dynamic production processes and stochastic energy consumption;
- incompleteness and low degree of reliability of information about the parameters and modes of their functioning.
It is important to note that in the district heating network, unlike other pipeline systems, they serve to transport not the product, but the energy of the coolant, the parameters of which must meet the requirements of various consumer systems.
These features emphasize the essential need for the creation of automated process control systems (hereinafter referred to as APCS), the introduction of which makes it possible to increase energy and environmental efficiency, reliability and quality of functioning of heat supply systems. The introduction of automated process control systems today is not a tribute to fashion, but follows from the basic laws of the development of technology and is economically justified at the present stage of development of the technosphere.
| REFERENCE |
The district heating system of Minsk is a structurally complex complex. In terms of production and transport of thermal energy, it includes the facilities of Minskenergo RUE (Minsk Heat Networks, heating complexes of CHPP-3 and CHPP-4) and the facilities of Minskkommunteploset Unitary Enterprise - boiler houses, heat networks and central heating points. Creation of APCS UE "Minskkommunteploset" was started in 1999, and now it is functioning, covering almost all heat sources (over 20) and a number of districts of heat networks. The development of the APCS project for the Minsk Heat Networks was launched in 2010, the project implementation began in 2012 and is currently ongoing. |
Development of an automated process control system for the heat supply system in Minsk
On the example of Minsk, we present the main approaches that have been implemented in a number of cities in Belarus and Russia in the design and development of process control systems for heat supply systems.
Taking into account the vastness of issues covering the subject area of heat supply, and the accumulated experience in the field of automation of heat supply systems at the pre-project stage of creating an automated process control system for Minsk heat networks, a concept was developed. The concept defines the fundamental foundations of the organization of automated process control systems for heat supply in Minsk (see reference) as a process of creating a computer network (system) focused on automating technological processes of a topologically distributed district heating enterprise.
Technological information tasks of process control systems
The implemented automated control system primarily provides for increasing the reliability and quality of operational control of the modes of operation of individual elements and the heat supply system as a whole. Therefore, this process control system is designed to solve the following technological information problems:
- provision of centralized functional-group control of hydraulic regimes of heat sources, main heat networks and pumping stations, taking into account daily and seasonal changes in circulation costs with adjustment (feedback) according to actual hydraulic regimes in the distribution heat networks of the city;
- implementation of the method of dynamic central control of heat supply with optimization of heat carrier temperatures in the supply and return pipelines of heating mains;
- ensuring the collection and archiving of data on the thermal and hydraulic modes of operation of heat sources, main heating networks, a pumping station and distribution heating networks of the city for monitoring, operational management and analysis of the functioning of the Minsk heating networks' central heating system;
- creation of an effective system for protecting equipment of heat sources and heating networks in emergency situations;
creation of an information base for solving optimization problems arising in the course of operation and modernization of objects of the Minsk heat supply system.
| REFERENCE 1 |
The structure of the Minsk thermal networks includes 8 network districts (RTS), 1 thermal power plant, 9 boiler houses with a capacity of several hundred to a thousand megawatts. In addition, 12 step-down pumping stations and 209 central heating stations are serviced by the Minsk Heat Networks. Organizational and production structure of the Minsk heat networks according to the "bottom-up" scheme:
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The structure of the automated process control system of Minsk heating networks
In accordance with the production and organizational structure of the Minsk Heat Networks (see Reference 1), a four-level structure of the APCS of the Minsk Heat Networks was chosen:
- the first (upper) level is the central control room of the enterprise;
- the second level - operator stations of districts of thermal networks;
- third level - operator stations of heat sources (operator stations of workshop sections of heating networks);
- fourth (lower) level - stations for automatic control of installations (boiler units) and processes of transport and distribution of thermal energy (technological scheme of a heat source, heating points, heating networks, etc.).
The development (creation of an automated process control system for heat supply of the entire city of Minsk) involves the inclusion in the system at the second structural level of operator stations of heating complexes of Minsk CHPP-2, CHPP-3, CHPP-4 and an operator station (central dispatching room) of UE "Minskkommunteploset". All management levels are planned to be combined into a single computer network.
The architecture of the process control system for the heat supply system of Minsk
The analysis of the control object as a whole and the state of its individual elements, as well as the prospects for the development of the control system, made it possible to propose the architecture of a distributed automated control system for technological processes of the Minsk heat supply system within the facilities of RUE "Minskenergo". The corporate network integrates the computing resources of the central office and remote structural subdivisions, including automatic control stations (ACS) of objects in network areas. All ACS (TsTP, ITP, PNS) and scanning stations are connected directly to the operator stations of the respective network areas, presumably installed at master sites.
On the remote structural unit(for example, RTS-6) the following stations are installed (Fig. 1): operator station "RTS-6" (OPS RTS-6) - it is the control center of the network area and is installed on the master section of RTS-6. For operational personnel, RTS-6 provides access to all information and control resources of ACS of all types, without exception, as well as access to authorized information resources of the central office. OpS RTS-6 provide regular scanning of all slave control stations.
The operational and commercial information collected from all central heating centers is sent for storage to a dedicated database server (installed in close proximity to the RTS-6 OpS).
Thus, taking into account the scale and topology of the control object and the existing organizational and production structure of the enterprise, the APCS of the Minsk Heat Networks is built according to a multi-link scheme using a hierarchical structure of software and hardware and computer networks that solve various control tasks at each level.
Management system levels
At the lower level, the control system performs:
- preliminary processing and transmission of information;
- regulation of the main technological parameters, functions of control optimization, protection of technological equipment.
Higher reliability requirements are imposed on lower-level hardware, including the possibility of autonomous operation in case of loss of connection with the upper-level computer network.
The subsequent levels of the control system are built according to the hierarchy of the heat supply system and solve the tasks of the corresponding level, as well as provide an operator interface.
Control devices installed at facilities, in addition to their direct duties, should also provide for the possibility of aggregating them into distributed control systems. The control device must ensure the operability and safety of the information of objective primary accounting during long interruptions in communication.
The main elements of such a scheme are technological and operator stations interconnected by communication channels. The core of the technological station should be an industrial computer equipped with means of communication with the control object and channel adapters for organizing interprocessor communication. The main purpose of the technological station is the implementation of direct digital control algorithms. In technically justified cases, some functions can be performed in supervisory mode: the process station processor can control remote intelligent controllers or software logic modules using modern field interface protocols.
Informational aspect of building an automated process control system for heat supply
Particular attention during the development was paid to the informational aspect of building an automated process control system for heat supply. The completeness of the description of the production technology and the perfection of information conversion algorithms are the most important part information support APCS built on direct digital control technology. The information capabilities of the automated process control system for heat supply provide the ability to solve a set of engineering problems that classify:
- by stages of the main technology (production, transport and consumption of thermal energy);
- by purpose (identification, forecasting and diagnostics, optimization and management).
When creating an automated process control system for the Minsk heat networks, it is planned to form an information field that allows you to quickly solve the entire complex of the above tasks of identification, forecasting, diagnostics, optimization and management. At the same time, information provides the possibility of solving system problems of the upper level of management when further development and expansion of automated process control systems as the relevant technical services for the main technological process are included.
In particular, this applies to optimization tasks, i.e., optimizing the production of thermal and electrical energy, modes of supply of thermal energy, flow distribution in thermal networks, operating modes of the main technological equipment of heat sources, as well as calculating the rationing of fuel and energy resources, energy accounting and operation, planning and forecasting the development of the heat supply system. In practice, the solution of some problems of this type is carried out within the framework of the enterprise automated control system. In any case, they must take into account the information obtained in the course of solving the problems of directly controlling the technological process, and the information system created by the process control system must be integrated with other information systems enterprises.
Methodology of software-object programming
The construction of the control system software, which is an original development of the center's team, is based on the methodology of program-object programming: software objects are created in the memory of control and operator stations that display real processes, units and measuring channels of an automated technological object. The interaction of these software objects (processes, aggregates and channels) with each other, as well as with operational personnel and with technological equipment, in fact, ensures the functioning of the elements of heat networks according to predefined rules or algorithms. Thus, the description of algorithms is reduced to the description of the most essential properties of these program objects and the ways of their interaction.
Synthesis of the structure of the control system of technical objects is based on the analysis technological scheme control object and detailed description technologies of the main processes and functioning inherent in this object as a whole.
A convenient tool for compiling this type of description for heat supply facilities is the methodology of mathematical modeling at the macro level. In the course of compiling a description of technological processes, a mathematical model, parametric analysis is performed and a list of adjustable and controlled parameters and regulatory bodies is determined.
The regime requirements of technological processes are specified, on the basis of which the boundaries of the permissible ranges for changing the regulated and controlled parameters and the requirements for the choice of actuators and regulatory bodies are determined. Based on the generalized information, the synthesis of an automated object control system is carried out, which, when using the direct digital control method, is built according to a hierarchical principle in accordance with the hierarchy of the control object.
ACS of the district boiler house
So, for a district boiler house (Fig. 2), an automated control system is built on the basis of two classes.
The upper level is the operator station "Boiler" (OPS "Boiler") - the main station that coordinates and controls the subordinate stations. Fire station “Boiler reserve” is a hot standby station, which is constantly in the mode of listening and registering the traffic of the main fire station and its subordinate ACS. Its database contains up-to-date parameters and complete historical data on the functioning of the working control system. At any time, a backup station can be assigned as the main station with full traffic transfer to it and the permission of supervisory control functions.
The lower level is a complex of automatic control stations united together with the operator station in a computer network:
- ACS "Boiler unit" provides control of the boiler unit. As a rule, it is not reserved, since the reservation of the thermal power of the boiler house is carried out at the level of boiler units.
- ACS "Grid Group" is responsible for the thermal-hydraulic mode of operation of the boiler house (control of a group of network pumps, bypass line at the outlet of the boiler room, bypass line, inlet and outlet valves of boilers, individual boiler recirculation pumps, etc.).
- SAU "Vodopodgotovka" provides control of all auxiliary equipment of the boiler house, necessary for feeding the network.
For simpler objects of the heat supply system, for example, heat points and block boiler houses, the control system is built as a single-level one based on an automatic control station (SAU TsTP, SAU BMK). In accordance with the structure of heat networks, the control stations of heat points are combined into a local computer network of the heat grid area and are connected to the operator station of the heat grid area, which, in turn, has information connection with operator station more high level integration.
Operator stations
The operator station software provides a user-friendly interface for the operating personnel controlling the operation of the automated technological complex. Operator stations have advanced means of operational dispatch control, as well as mass memory devices for organizing short-term and long-term archives of the state of the parameters of the technological control object and the actions of operational personnel.
In cases of large information flows that are closed to operational personnel, it is advisable to organize several operator stations with the allocation of a separate database server and, possibly, a communication server.
The operator station, as a rule, does not directly affect the control object itself - it receives information from technological stations and transmits directives to the operating personnel or tasks (settings) of supervisory control, generated automatically or semi-automatically. It forms workplace operator of a complex object, such as a boiler room.
The automated control system being created provides for the construction of an intelligent superstructure, which should not only track disturbances that occur in the system and respond to them, but also predict the occurrence of emergency situations and block their occurrence. When changing the topology of the heat supply network and the dynamics of its processes, it is possible to adequately change the structure of the distributed control system by adding new control stations and (or) changing software objects without changing the equipment configuration of existing stations.
Efficiency of APCS of the heat supply system
An analysis of the operating experience of automated process control systems for heat supply enterprises 1 in a number of cities in Belarus and Russia, conducted over the past twenty years, showed them economic efficiency and confirmed the viability of the architecture, software and hardware decisions made.
In terms of their properties and characteristics, these systems meet the requirements of the ideology of smart grids. Nevertheless, work is constantly underway to improve and develop the developed automated control systems. The introduction of automated process control systems for heat supply increases the reliability and efficiency of the DH operation. The main saving of fuel and energy resources is determined by the optimization of the thermal-hydraulic modes of heating networks, the operating modes of the main and auxiliary equipment of heat sources, pumping stations and heating points.
Literature
- Gromov N.K. Urban heating systems. M. : Energy, 1974. 256 p.
- Popyrin L. S. Research of heat supply systems. M. : Nauka, 1989. 215 p.
- Ionin A. A. Reliability of systems of thermal networks. Moscow: Stroyizdat, 1989. 302 p.
- Monakhov G. V. Modeling of control modes of heat networks. M.: Energoatomizdat, 1995. 224 p.
- Sednin VA Theory and practice of creating automated heat supply control systems. Minsk: BNTU, 2005. 192 p.
- Sednin V. A. Implementation of automated process control systems as a fundamental factor in improving the reliability and efficiency of heat supply systems // Technology, equipment, quality. Sat. mater. Belarusian Industrial Forum 2007, Minsk, May 15–18, 2007 / Expoforum – Minsk, 2007, pp. 121–122.
- Sednin V. A. Optimization of the parameters of the temperature graph of heat supply in heating systems // Energetika. News of higher educational institutions and energy associations of the CIS. 2009. No. 4. S. 55–61.
- Sednin V. A. The concept of creating an automated process control system for Minsk heat networks / V. A. Sednin , A. V. Sednin, E. O. Voronov // Improving the efficiency of power equipment: Proceedings of the scientific and practical conference, in 2 v. T. 2. 2012. S. 481–500.
1 Created by the team of the Research and Innovation Center for Automated Control Systems in Heat Power and Industry of the Belarusian National Technical University.
V. G. Semenov, Editor-in-Chief, Heat Supply News
The concept of a system
Everyone is used to the expressions "heat supply system", "control system", "automated control systems". One of the simplest definitions of any system: a set of connected operating elements. A more complex definition is given by Academician P. K. Anokhin: “A system can only be called such a complex of selectively involved components, in which the interaction takes on the character of mutual assistance to obtain a focused useful result.” Obtaining such a result is the goal of the system, and the goal is formed on the basis of need. IN market economy technical systems, as well as their management systems, are formed on the basis of demand, i.e., a need for the satisfaction of which someone is willing to pay.
Technical heat supply systems consist of elements (CHP, boiler houses, networks, emergency services, etc.) that have very rigid technological connections. " external environment" For technical system heat supply are consumers of different types; gas, electric, water networks; weather; new developers, etc. They exchange energy, matter and information.
Any system exists within some limits imposed, as a rule, by buyers or authorized bodies. These are the requirements for the quality of heat supply, ecology, labor safety, price restrictions.
There are active systems that can resist negative impacts environment (unskilled actions of administrations different levels, competition of other projects...), and passive ones, which do not have this property.
Operational technical control systems for heat supply are typical human-machine systems, they are not very complex and are quite easy to automate. In fact, they are subsystems of a higher level system - heat supply management in a limited area.
Control systems
Management is the process of purposeful influence on the system, providing an increase in its organization, the achievement of one or another useful effect. Any control system is divided into control and controlled subsystems. The connection from the control subsystem to the controlled one is called direct connection. Such a connection always exists. The opposite direction of communication is called feedback. The concept of feedback is fundamental in technology, nature and society. It is believed that control without strong feedback is not effective, because it does not have the ability to self-detect errors, formulate problems, does not allow the use of the system's self-regulation capabilities, as well as the experience and knowledge of specialists.
SA Optner even believes that control is the goal of feedback. “Feedback affects the system. Impact is a means of changing the existing state of the system by excitation of a force that allows this to be done.
In a properly organized system, the deviation of its parameters from the norm or the deviation from the correct direction of development develops into feedback and initiates the management process. “The very deviation from the norm serves as an incentive to return to the norm” (P.K. Anokhin). It is also very important that the own purpose of the control system does not contradict the purpose of the controlled system, that is, the purpose for which it was created. It is generally accepted that the requirement of a "superior" organization is unconditional for a "lower" organization and is automatically transformed into a goal for it. This can sometimes lead to a substitution of the target.
The correct goal of the control system is the development of control actions based on the analysis of information about deviations, or, in other words, problem solving.
A problem is a situation of discrepancy between the desired and the existing. The human brain is arranged in such a way that a person begins to think in some direction only when a problem is revealed. Therefore, the correct definition of the problem predetermines the correct managerial decision. There are two categories of problems: stabilization and development.
Stabilization problems are called those, the solution of which is aimed at preventing, eliminating or compensating for disturbances that disrupt the current activity of the system. At the level of an enterprise, region or industry, the solution to these problems is referred to as production management.
The problems of development and improvement of systems are called those, the solution of which is aimed at improving the efficiency of functioning by changing the characteristics of the control object or control system.
From point of view systems approach the problem is the difference between the existing system and the desired system. The system that fills the gap between them is the object of construction and is called the solution to the problem.
Analysis of existing heat supply management systems
A systematic approach is an approach to the study of an object (problem, process) as a system in which elements, internal connections and connections with the environment that affect the results of functioning are identified, and the goals of each of the elements are determined based on the general purpose of the system.
The purpose of creating any centralized heat supply system is to provide high-quality, reliable heat supply at the lowest price. This goal suits consumers, citizens, administration and politicians. The same goal should be for the heat management system.
Today there is 2 main types of heat supply management systems:
1) the administration of the municipal formation or region and the heads of state heat supply enterprises subordinate to it;
2) governing bodies of non-municipal heat supply enterprises.
Rice. 1. Generalized scheme of the existing heat supply management system.
A generalized diagram of the heat supply control system is shown in fig. 1. It presents only those structures (environment) that can actually influence control systems:
Increase or decrease income;
Force to go to additional expenses;
Change the management of enterprises.
For a real analysis, we must start from the premise that only what is paid for or can be fired is performed, and not what is declared. State
There is practically no legislation regulating the activities of heat supply enterprises. Even the procedures for state regulation of local natural monopolies in heat supply are not spelled out.
Heat supply is the main problem in the reforms of housing and communal services and RAO "UES of Russia", it cannot be solved separately in either one or the other, therefore it is practically not considered, although it is through heat supply that these reforms should have been interconnected. There is not even a government-approved concept for the development of the country's heat supply, let alone a real program of action.
The federal authorities do not regulate the quality of heat supply in any way, there are not even regulatory documents that define the quality criteria. Reliability of heat supply is regulated only through technical supervisory authorities. But since the interaction between them and the tariff authorities is not spelled out in any regulatory document, it is often absent. Enterprises, on the other hand, have the opportunity not to comply with any instructions, justifying this with a lack of funding.
Technical supervision of existing regulatory documents is reduced to the control of individual technical units, and those for which there are more rules. The system in the interaction of all its elements is not considered, the measures that give the greatest system-wide effect are not identified.
The cost of heat supply is regulated only formally. Tariff legislation is so general that almost everything is left to the discretion of the federal and, to a greater extent, regional energy commissions. Heat consumption standards are regulated only for new buildings. IN government programs energy saving section on heat supply is practically absent.
As a result, the role of the state was relegated to the collection of taxes and, through supervisory authorities, information to local authorities about the shortcomings in the heat supply.
For the work of natural monopolies, for the functioning of industries that ensure the possibility of the existence of the nation, the executive branch is responsible to the parliament. The problem is not that the federal bodies are functioning unsatisfactorily, but that there is actually no structure in the structure of the federal bodies, from
Siemens is a recognized world leader in the development of systems for the energy sector, including heating and water supply systems. This is what one of the departments does. Siemens - Building Technologies – “Automation and safety of buildings”. The company offers a full range of equipment and algorithms for the automation of boiler houses, heat points and pumping stations.
1. Structure of the heating system
Siemens offers a comprehensive solution for creating a unified control system for urban heat and water supply systems. The complexity of the approach lies in the fact that everything is offered to customers, starting with hydraulic calculations of heat and water supply systems and ending with communication and dispatching systems. The implementation of this approach is ensured by the accumulated experience of the company's specialists, acquired in different countries around the world during the implementation of various projects in the field of heating systems for large cities in Central and Eastern Europe. This article discusses the structures of heat supply systems, the principles and control algorithms that were implemented in the implementation of these projects.
Heat supply systems are built mainly according to a 3-stage scheme, the parts of which are:
1. Heat sources of different types, interconnected into a single looped system
2. Central heating points (CHP) connected to the main heating networks with a high heat carrier temperature (130 ... 150 ° C). In the central heating center, the temperature gradually decreases to a maximum temperature of 110 ° C, based on the needs of the ITP. For small systems, the level of central heat points may be absent.
3. Individual heating points that receive thermal energy from the central heating station and provide heat supply to the facility.
The principal feature of Siemens solutions is that the whole system is based on the principle of 2-pipe distribution, which is the best technical and economic compromise. This solution makes it possible to reduce heat losses and electricity consumption in comparison with the 4-pipe or 1-pipe systems with open water intake, which are widely used in Russia, investments in the modernization of which without changing their structure are not effective. Maintenance costs for such systems are constantly increasing. Meanwhile, exactly economic effect is the main criterion for the expediency of development and technical improvement of the system. Obviously, when constructing new systems, optimal solutions that have been tested in practice should be adopted. If it's about overhaul non-optimal structure of heat supply systems, it is economically profitable to switch to a 2-pipe system with individual heating points in each house.
When providing consumers with heat and hot water, the management company incurs fixed costs, the structure of which looks like in the following way:
Heat generation costs for consumption;
losses in heat sources due to imperfect methods of heat generation;
heat losses in heating mains;
R electricity costs.
Each of these components can be reduced with optimal management and the use of modern automation tools at each level.
2. Heat sources
It is known that large CHP sources or those in which heat is a secondary product, such as industrial processes, are preferred for heating systems. It was on the basis of such principles that the idea of district heating was born. Boilers operating on different types of fuel are used as backup heat sources. gas turbines And so on. If gas-fired boilers serve as the main source of heat, they must operate with automatic optimization of the combustion process. This is the only way to achieve savings and reduce emissions compared to distributed heat generation in each house.
3. Pumping stations
Heat from heat sources is transferred to the main heating networks. The heat carrier is pumped over by network pumps which work continuously. Therefore, special attention should be paid to the selection and operation of pumps. The operating mode of the pump depends on the modes of the heating points. A decrease in the flow rate at the CHP entails an undesirable increase in the head of the pump(s). An increase in pressure negatively affects all components of the system. At best, only hydraulic noise increases. In either case, electrical energy is wasted. Under these conditions, an unconditional economic effect is provided with frequency control of pumps. Various control algorithms are used. In the basic scheme, the controller maintains a constant differential pressure across the pump by changing the speed. Due to the fact that with a decrease in the flow rate of the coolant, the pressure losses in the lines are reduced (quadratic dependence), it is also possible to reduce the setpoint (setpoint) of the pressure drop. This control of pumps is called proportional and allows you to further reduce the cost of operating the pump. More efficient control of pumps with correction of the task by the “remote point”. In this case, the pressure drop at the end points of the main networks is measured. The current differential pressure values compensate for the pressures at the pumping station.
4. Central heating points (CHP)
Central heating systems play a very important role in modern heating systems. An energy-saving heat supply system should work with the use of individual heat points. However, this does not mean that central heating stations will be closed: they act as a hydraulic stabilizer and at the same time divide the heat supply system into separate subsystems. In the case of the use of ITP, systems of central hot water supply are excluded from the central heating station. At the same time, only 2 pipes pass through the central heating station, separated by a heat exchanger, which separates the system of main routes from the ITP system. Thus, the ITP system can operate with other coolant temperatures, as well as with lower dynamic pressures. This guarantees the stable operation of the ITP and at the same time entails a reduction in investments in the ITP. The supply temperature from the CHP is corrected in accordance with the temperature schedule according to the outdoor temperature, taking into account the summer limitation, which depends on the demand of the DHW system in the CHP. We are talking about a preliminary adjustment of the coolant parameters, which makes it possible to reduce heat losses in the secondary routes, as well as increase the service life of the thermal automation components in the ITP.
5. Individual heating points (ITP)
The operation of the ITP affects the efficiency of the entire heat supply system. ITP is a strategically important part of the heat supply system. The transition from a 4-pipe system to a modern 2-pipe system is associated with certain difficulties. Firstly, this entails the need for investment, and secondly, without a certain “know-how”, the introduction of ITP can, on the contrary, increase current expenses management company. The principle of operation of the ITP is that the heating point is located directly in the building, which is heated and for which hot water is prepared. At the same time, only 3 pipes are connected to the building: 2 for the coolant and 1 for cold water supply. Thus, the structure of the pipelines of the system is simplified, and during the planned repair of the routes, savings on laying pipes immediately take place.
5.1. Heating circuit control
The ITP controller controls the heat output of the heating system by changing the temperature of the coolant. The heating temperature setpoint is determined from the outside temperature and the heating curve (weather-compensated control). The heating curve is determined taking into account the inertia of the building.
5.2. Building inertia
The inertia of buildings has a significant impact on the result of weather-compensated heating control. A modern ITP controller must take into account this influencing factor. The inertia of the building is determined by the value of the time constant of the building, which ranges from 10 hours for panel houses to 35 hours for brick houses. Based on the time constant of the building, the IHS controller determines the so-called "combined" outdoor temperature, which is used as a correction signal in the automatic heating water temperature control system.
5.3. wind force
The wind significantly affects the room temperature, especially in high-rise buildings located in open areas. The algorithm for correcting water temperature for heating, taking into account the influence of wind, provides up to 10% savings in thermal energy.
5.4 Return temperature limitation
All the types of control described above indirectly affect the return water temperature reduction. This temperature is the main indicator of the economical operation of the heating system. With various modes of operation of the IHS, the return water temperature can be reduced using the limitation functions. However, all limiting functions entail deviations from comfort conditions, and their use must be supported by a feasibility study. In independent schemes for connecting the heating circuit, with economical operation of the heat exchanger, the temperature difference between the return water of the primary circuit and the heating circuit should not exceed 5 ° C. Economy is ensured by the function of dynamic limitation of the return water temperature ( DRT – differential of return temperature ): when the set value of the return temperature difference between the primary circuit and the heating circuit is exceeded, the controller reduces the heating medium flow in the primary circuit. At the same time, the peak load also decreases (Fig. 1).
Rice. 6. Two-wire line with two corona wires at different distances between them
16 m; 3 - bp = 8 m; 4 - b,
BIBLIOGRAPHY
1. Efimov B.V. Storm waves in air lines. Apatity: Publishing House of the KSC RAS, 2000. 134 p.
2. Kostenko M.V., Kadomskaya K.P., Levinshgein M.L., Efremov I.A. Overvoltage and protection against them in
high voltage overhead and cable power lines. L.: Nauka, 1988. 301 p.
A.M. Prokhorenkov
METHODS FOR BUILDING AN AUTOMATED SYSTEM OF DISTRIBUTED HEAT SUPPLY CONTROL OF THE CITY
Considerable attention is paid to the issues of introducing resource-saving technologies in modern Russia. These issues are especially acute in the regions of the Far North. Fuel oil for urban boiler houses is fuel oil, which is delivered by rail from the central regions of Russia, which significantly increases the cost of generated thermal energy. Duration
the heating season in the conditions of the Arctic is 2-2.5 months longer compared to central regions countries, which is associated with the climatic conditions of the Far North. At the same time, heat and power enterprises must generate the necessary amount of heat in the form of steam, hot water under certain parameters (pressure, temperature) to ensure the vital activity of all urban infrastructures.
Reducing the cost of generating heat supplied to consumers is possible only through economical combustion of fuel, rational use electricity for the own needs of enterprises, minimizing heat losses in the areas of transportation (heat networks of the city) and consumption (buildings, enterprises of the city), as well as reducing the number of service personnel at production sites.
The solution of all these problems is possible only through the introduction of new technologies, equipment, technical controls that make it possible to ensure the economic efficiency of the operation of thermal power enterprises, as well as to improve the quality of management and operation of thermal power systems.
Formulation of the problem
One of the important tasks in the field of urban heating is the creation of heat supply systems with the parallel operation of several heat sources. Modern systems district heating systems of cities have developed as very complex, spatially distributed systems with closed circulation. As a rule, consumers do not have the property of self-regulation, the distribution of the coolant is carried out by preliminary installation of specially designed (for one of the modes) constant hydraulic resistances [1]. In this regard, the random nature of the selection of thermal energy by consumers of steam and hot water leads to dynamically complex transient processes in all elements of a thermal power system (TPP).
Operational control of the state of remote facilities and control of equipment located at controlled points (CP) is impossible without the development of an automated system for dispatch control and management of central heating points and pumping stations (ASDK and U TsTP and NS) of the city. Therefore, one of actual problems is the management of thermal energy flows, taking into account the hydraulic characteristics of both the heating networks themselves and energy consumers. It requires solving problems related to the creation of heat supply systems, where in parallel
Several heat sources (thermal stations - TS)) operate on the general heat network of the city and on the general heat load schedule. Such systems make it possible to save fuel during heating, increase the degree of loading of the main equipment, and operate boiler units in modes with optimal efficiency values.
Solving the problems of optimal control of technological processes of a heating boiler house
To solve the problems of optimal control of technological processes of the heating boiler house "Severnaya" of the State Regional Heat and Power Enterprise (GOTEP) "TEKOS", within the framework of a grant from the Import Program for Energy-Saving and Environmental Protection Equipment and Materials (PIEPOM) of the Russian-American Committee, equipment was supplied (funded by the US government). This equipment and the software developed for it made it possible to solve a wide range of problems of reconstruction on base enterprise GOTEP "TEKOS", and the results obtained - to replicate to the heat and power enterprises of the region.
The basis for the reconstruction of control systems for TS boiler units was the replacement of obsolete automation tools of the central control panel and local automatic control systems with a modern microprocessor-based distributed control system. The implemented distributed control system for boilers based on the microprocessor system (MPS) TDC 3000-S (Supper) from Honeywell provided a single integrated solution for the implementation of all system functions for controlling technological processes of the TS. The operated MPS has valuable qualities: simplicity and visibility of the layout of control and operation functions; flexibility in fulfilling all the requirements of the process, taking into account reliability indicators (working in the "hot" standby mode of the second computer and USO), availability and efficiency; easy access to all system data; ease of change and expansion of service functions without feedback on the system;
improved quality of presentation of information in a form convenient for decision-making (friendly intelligent operator interface), which helps to reduce errors of operational personnel in the operation and control of TS processes; computer creation of documentation for process control systems; increased operational readiness of the object (the result of self-diagnostics of the control system); promising system with a high degree of innovation. In the TDC 3000 - S system (Fig. 1) it is possible to connect external PLC controllers from other manufacturers (this possibility is implemented if there is a PLC gateway module). Information from PLC controllers is displayed
It is displayed in the TOC as an array of points available for reading and writing from user programs. This makes it possible to use distributed I/O stations installed in close proximity to controlled objects for data collection and transfer data to TOC via an information cable using one of the standard protocols. This option allows you to integrate new control objects, including an automated system for dispatching control and management of central heating points and pumping stations (ASDKiU TsTPiNS), into the existing automated process control system of the enterprise without external changes for users.
local computer network
Universal stations
Computer Applied Historical
gateway module module
The local network management
Backbone gateway
I Reserve (ARMM)
Enhancement Module. Advanced Process Manager (ARMM)
Universal control network
I/O controllers
Cable routes 4-20 mA
I/O station SIMATIC ET200M.
I/O controllers
Network of PLC devices (PROFIBUS)
Cable routes 4-20 mA
Flow sensors
Temperature sensors
Pressure Sensors
Analyzers
Regulators
Frequency stations
gate valves
Flow sensors
Temperature sensors
Pressure Sensors
Analyzers
Regulators
Frequency stations
gate valves
Rice. 1. Collecting information by distributed PLC stations, transferring it to the TDC3000-S for visualization and processing, followed by the issuance of control signals
The conducted experimental studies have shown that the processes occurring in the steam boiler in the operating modes of its operation are of a random nature and are non-stationary, which is confirmed by the results of mathematical processing and statistical analysis. Taking into account the random nature of the processes occurring in the steam boiler, estimates of the shift of the mathematical expectation (MO) M(t) and dispersion 5 (?) along the main coordinates of control are taken as a measure of assessing the quality of control:
Em, (t) 2 MZN (t) - MrN (t) ^ gMix (t) ^ min
where Mzn(t), Mmn(t) are the set and current MO of the main adjustable parameters of the steam boiler: the amount of air, the amount of fuel, and the steam output of the boiler.
s 2 (t) = 8|v (t) - q2N (t) ^ s^ (t) ^ min, (2)
where 52Tn, 5zn2(t) are the current and set variances of the main controlled parameters of the steam boiler.
Then the control quality criterion will have the form
Jn = I [avMy(t) + ßsö;, (t)] ^ min, (3)
where n = 1,...,j; - ß - weight coefficients.
Depending on the operating mode of the boiler (regulating or basic), an optimal control strategy should be formed.
For the control mode of operation of the steam boiler, the control strategy should be aimed at maintaining the pressure in the steam collector constant, regardless of the steam consumption by heat consumers. For this mode of operation, the estimate of the displacement of the steam pressure in the main steam header in the form
ep (/) = Pz(1) - Pm () ^B^ (4)
where VD, Pt(0 - set and current average values of steam pressure in the main steam header.
The displacement of steam pressure in the main steam collector by dispersion, taking into account (4), has the form
(0 = -4r(0 ^^ (5)
where (UrzOO, art(0 - given and current pressure dispersions.
Fuzzy logic methods were used to adjust the transfer coefficients of the regulators of the circuits of the multi-connected boiler control system.
During the pilot operation of automated steam boilers, statistical material was accumulated, which made it possible to obtain comparative (with the operation of non-automated boiler units) characteristics of the technical and economic efficiency of introducing new methods and controls and to continue reconstruction work on other boilers. So, for the period of semi-annual operation of non-automated steam boilers No. 9 and 10, as well as automated steam boilers No. 13 and 14, the results were obtained, which are presented in Table 1.
Determination of parameters for optimal loading of a thermal plant
To determine the optimal load of the vehicle, it is necessary to know the energy characteristics of their steam generators and the boiler house as a whole, which are the relationship between the amount of fuel supplied and the heat received.
The algorithm for finding these characteristics includes the following steps:
Table 1
Boiler performance indicators
Name of indicator Value of indicators for milking boilers
№9-10 № 13-14
Heat generation, Gcal Fuel consumption, t Specific rate of fuel consumption for the generation of 1 Gcal of thermal energy, kg of reference fuel cal 170,207 20,430 120.03 217,626 24,816 114.03
1. Determination of the thermal performance of boilers for various load modes of their operation.
2. Determination of heat losses A () taking into account the efficiency of boilers and their payload.
3. Determination of the load characteristics of boiler units in the range of their change from the minimum allowable to the maximum.
4. Based on the change in the total heat losses in steam boilers, the determination of their energy characteristics, reflecting the hourly consumption of standard fuel, according to the formula 5 = 0.0342 (0, + AC?).
5. Obtaining the energy characteristics of boiler houses (TS) using the energy characteristics of boilers.
6. Forming, taking into account the energy characteristics of the TS, control decisions on the sequence and order of their loading during the heating period, as well as in the summer season.
Another important issue of organizing the parallel operation of sources (TS) is the determination of factors that have a significant impact on the load of boiler houses, and the tasks of the heat supply management system to provide consumers with the necessary amount of heat energy when possible. minimal cost for its production and transmission.
The solution of the first problem is carried out by linking the supply schedules with the schedules of heat use by means of a system of heat exchangers, the solution of the second one is by establishing the correspondence between the heat load of consumers and its production, i.e., by planning the change in load and reducing losses in the transmission of heat energy. Ensuring the linking of schedules for the supply and use of heat should be carried out through the use of local automation at intermediate stages from sources of thermal energy to its consumers.
To solve the second problem, it is proposed to implement the functions of estimating the planned load of consumers, taking into account the economically justified possibilities of energy sources (ES). Such an approach is possible using situational control methods based on the implementation of fuzzy logic algorithms. The main factor that has a significant impact on
the heat load of boiler houses is that part of it that is used for heating buildings and for hot water supply. The average heat flow (in Watts) used for heating buildings is determined by the formula
where /from - the average outdoor temperature for a certain period; r( - the average temperature of the indoor air of the heated room (the temperature that must be maintained at a given level); / 0 - the estimated outdoor air temperature for heating design;<70 - укрупненный показатель максимального теплового потока на отопление жилых и общественных зданий в Ваттах на 1 м площади здания при температуре /0; А - общая площадь здания; Кх - коэффициент, учитывающий тепловой поток на отопление общественных зданий (при отсутствии конкретных данных его можно считать равным 0,25).
It can be seen from formula (6) that the heat load on the heating of buildings is determined mainly by the outside air temperature.
The average heat flow (in Watts) for hot water supply of buildings is determined by the expression
1.2w(a + ^)(55 - ^) p
Yt „. " _ With"
where m is the number of consumers; a - the rate of water consumption for hot water supply at a temperature of +55 ° C per person per day in liters; b - the rate of water consumption for hot water supply consumed in public buildings at a temperature of +55 ° C (assumed to be 25 liters per day per person); c is the heat capacity of water; /x - temperature of cold (tap) water during the heating period (assumed to be +5 °C).
Analysis of expression (7) showed that when calculating the average heat load on hot water supply, it turns out to be constant. The real extraction of thermal energy (in the form of hot water from the tap), in contrast to the calculated value, is random, which is associated with an increase in the analysis of hot water in the morning and evening, and a decrease in the selection during the day and night. On fig. 2, 3 shows graphs of change
Oil 012 013 014 015 016 017 018 019 1 111 112 113 114 115 116 117 118 119 2 211 212 213 214 215 216 217 218 219 3 311 312 31 3 314 315 316 317
days of the month
Rice. 2. Graph of changes in water temperature in the CHP N9 5 (7 - direct boiler water,
2 - direct quarterly, 3 - water for hot water supply, 4 - reverse quarterly, 5 - return boiler water) and outdoor air temperatures (6) for the period from February 1 to February 4, 2009
pressure and temperature of hot water for TsTP No. 5, which were obtained from the archive of SDKi U TsTP and NS of Murmansk.
With the onset of warm days, when the ambient temperature does not drop below +8 °C for five days, the heating load of consumers is turned off and the heating network works for the needs of hot water supply. The average heat flow to the hot water supply during the non-heating period is calculated by the formula
where is the temperature of cold (tap) water during the non-heating period (assumed to be +15 °С); p - coefficient taking into account the change in the average water consumption for hot water supply in the non-heating period in relation to the heating period (0.8 - for the housing and communal sector, 1 - for enterprises).
Taking into account formulas (7), (8), heat load graphs of energy consumers are calculated, which are the basis for constructing tasks for the centralized regulation of the supply of thermal energy of the TS.
Automated system of dispatching control and management of central heating points and pumping stations of the city
A specific feature of the city of Murmansk is that it is located on a hilly area. The minimum elevation is 10 m, the maximum is 150 m. In this regard, the heating networks have a heavy piezometric graph. Due to the increased water pressure in the initial sections, the accident rate (pipe ruptures) increases.
For operational control of the state of remote objects and control of equipment located at controlled points (CP),
Rice. Fig. 3. Graph of water pressure change in central heating station N° 5 for the period from February 1 to February 4, 2009: 1 - hot water supply, 2 - direct boiler water, 3 - direct quarterly, 4 - reverse quarterly,
5 - cold, 6 - return boiler water
was developed by ASDKiUCTPiNS of the city of Murmansk. Controlled points, where telemechanics equipment was installed during the reconstruction works, are located at a distance of up to 20 km from the head enterprise. Communication with the telemechanics equipment at the CP is carried out via a dedicated telephone line. Central boiler rooms (CTPs) and pumping stations are separate buildings in which technological equipment is installed. The data from the control panel are sent to the control room (in the dispatcher's PCARM) located on the territory of the Severnaya TS of the TEKOS enterprise, and to the TS server, after which they become available to users of the enterprise's local area network to solve their production problems.
In accordance with the tasks solved with the help of ASDKiUTSTPiNS, the complex has a two-level structure (Fig. 4).
Level 1 (upper, group) - dispatcher console. The following functions are implemented at this level: centralized control and remote control of technological processes; display of data on the display of the control panel; formation and issuance of
even documentation; formation of tasks in the automated process control system of the enterprise for managing the modes of parallel operation of the city's thermal stations for the general city heat network; access of users of the local network of the enterprise to the database of the technological process.
Level 2 (local, local) - CP equipment with sensors placed on them (alarms, measurements) and final actuating devices. At this level, the functions of collecting and primary processing of information, issuing control actions on actuators are implemented.
Functions performed by ASDKiUCTPiNS of the city
Information functions: control of readings of pressure sensors, temperature, water flow and control of the state of actuators (on/off, open/close).
Control functions: control of network pumps, hot water pumps, other technological equipment of the gearbox.
Visualization and registration functions: all information parameters and alarm parameters are displayed on trends and mnemonic diagrams of the operator station; all information
PC workstation of the dispatcher
Adapter SHV/K8-485
Dedicated phone lines
KP controllers
Rice. 4. Block diagram of the complex
parameters, signaling parameters, control commands are registered in the database periodically, as well as in cases of state change.
Alarm functions: power outage at the gearbox; activation of the flooding sensor at the checkpoint and security at the checkpoint; signaling from sensors of limiting (high/low) pressure in pipelines and transmitters of emergency changes in the state of actuators (on/off, open/close).
The concept of a decision support system
A modern automated process control system (APCS) is a multi-level human-machine control system. The dispatcher in a multilevel automated process control system receives information from a computer monitor and acts on objects located at a considerable distance from it, using telecommunication systems, controllers, and intelligent actuators. Thus, the dispatcher becomes the main character in the management of the technological process of the enterprise. Technological processes in thermal power engineering are potentially dangerous. So, for thirty years, the number of recorded accidents doubles approximately every ten years. It is known that in the steady state modes of complex energy systems, errors due to inaccuracy of the initial data are 82-84%, due to the inaccuracy of the model - 14-15%, due to the inaccuracy of the method - 2-3%. Due to the large share of the error in the initial data, there is also an error in the calculation of the objective function, which leads to a significant area of uncertainty when choosing the optimal mode of operation of the system. These problems can be eliminated if we consider automation not just as a way to replace manual labor directly in production management, but as a means of analysis, forecasting and control. The transition from dispatching to a decision support system means a transition to a new quality - an intelligent information system of an enterprise. Any accident (except natural disasters) is based on human (operator) error. One of the reasons for this is the old, traditional approach to building complex control systems, focused on the use of the latest technology.
scientific and technological achievements while underestimating the need to use situational management methods, methods of integrating control subsystems, as well as building an effective human-machine interface focused on a person (dispatcher). At the same time, it is envisaged to transfer the functions of the dispatcher for data analysis, forecasting situations and making appropriate decisions to the components of intelligent decision support systems (ISDS) . The SPID concept includes a number of tools united by a common goal - to promote the adoption and implementation of rational and effective management decisions. SPPIR is an interactive automated system that acts as an intelligent intermediary that maintains a natural language user interface with a 3CAOA system and uses decision rules that correspond to the model and base. Along with this, the SPPIR performs the function of automatic tracking of the dispatcher at the stages of information analysis, recognition and forecasting of situations. On fig. Figure 5 shows the structure of the SPPIR, with the help of which the TS dispatcher manages the heat supply of the microdistrict.
Based on the above, several fuzzy linguistic variables can be identified that affect the load of the TS, and, consequently, the operation of heat networks. These variables are given in Table. 2.
Depending on the season, time of day, day of the week, as well as the characteristics of the external environment, the situation assessment unit calculates the technical condition and the required performance of thermal energy sources. This approach allows solving the problems of fuel economy in district heating, increasing the degree of loading of the main equipment, and operating boilers in modes with optimal efficiency values.
The construction of an automated system for distributed control of the heat supply of the city is possible under the following conditions:
introduction of automated control systems for boiler units of heating boiler houses. (Implementation of automated process control systems at the TS "Severnaya"
Rice. 5. The structure of the SPPIR of the heating boiler house of the microdistrict
table 2
Linguistic variables determining the load of a heating boiler house
Notation Name Range of values (universal set) Terms
^month Month January to December Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov , "dec"
T-week Day of the week working or weekend "working", "holiday"
TSug Time of day from 00:00 to 24:00 "night", "morning", "day", "evening"
t 1 n.v Outside air temperature from -32 to +32 ° С "lower", "-32", "-28", "-24", "-20", "-16", "-12", "-8", "^1", "0", "4", "8", "12", "16", "20", "24", "28", "32", "above"
1" in Wind speed from 0 to 20 m/s "0", "5", "10", "15", "higher"
provided a reduction in the specific fuel consumption rate for boilers No. 13.14 compared to boilers No. 9.10 by 5.2%. Energy savings after the installation of frequency vector converters on the drives of fans and smoke exhausters of boiler No. 13 amounted to 36% (specific consumption before reconstruction - 3.91 kWh/Gcal, after reconstruction - 2.94 kWh/Gcal, and
No. 14 - 47% (specific electricity consumption before reconstruction - 7.87 kWh/Gcal., after reconstruction - 4.79 kWh/Gcal));
development and implementation of ASDKiUCTPiNS of the city;
introduction of information support methods for TS operators and ASDKiUCTPiNS of the city using the concept of SPPIR.
BIBLIOGRAPHY
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The article is devoted to the use of the Trace Mode SCADA system for operational remote control of district heating facilities in the city. The facility where the described project was implemented is located in the south of the Arkhangelsk region (the city of Velsk). The project provides for operational monitoring and management of the process of preparing and distributing heat for heating and supplying hot water to vital facilities of the city.
CJSC SpetsTeploStroy, Yaroslavl
Statement of the problem and the necessary functions of the system
The goal that our company faced was to build a main network for heating a large part of the city, using advanced construction methods, where pre-insulated pipes were used to build the network. For this, fifteen kilometers of main heating networks and seven central heating points (CHPs) were built. Purpose of the central heating station - using superheated water from the GT-CHP (according to the schedule 130/70 °С), it prepares the heat carrier for intra-quarter heating networks (according to the schedule 95/70 °С) and heats the water up to 60 °С for the needs of domestic hot water supply (hot water supply), The TsTP operates on an independent, closed scheme.
When setting the task, many requirements were taken into account that ensure the energy-saving principle of operation of the CHP. Here are some of the most important ones:
To carry out weather-dependent control of the heating system;
Maintain the DHW parameters at a given level (temperature t, pressure P, flow G);
Maintain at a given level the parameters of the coolant for heating (temperature t, pressure P, flow G);
Organize commercial accounting of thermal energy and heat carrier in accordance with the current regulatory documents (RD);
Provide ATS (automatic transfer of reserve) pumps (network and hot water supply) with motor resource equalization;
Perform correction of the main parameters according to the calendar and real time clock;
Perform periodic data transmission to the control room;
Perform diagnostics of measuring instruments and operating equipment;
Lack of staff on duty at the central heating station;
Monitor and promptly report to maintenance personnel on the occurrence of emergency situations.
As a result of these requirements, the functions of the operational-remote control system being created were determined. The main and auxiliary means of automation and data transmission were selected. A choice of SCADA-system was made to ensure the operability of the system as a whole.
Necessary and sufficient functions of the system:
1_Information functions:
Measurement and control of technological parameters;
Signaling and registration of parameter deviations from the established limits;
Formation and issuance of operational data to personnel;
Archiving and viewing the history of parameters.
2_Control functions:
Automatic regulation of important process parameters;
Remote control of peripheral devices (pumps);
Technological protection and blocking.
3_Service functions:
Self-diagnostics of software and hardware complex in real time;
Data transmission to the control room on schedule, upon request and in the event of an emergency;
Testing the operability and correct functioning of computing devices and input/output channels.
What influenced the choice of automation tools
and software?
The choice of basic automation tools was mainly based on three factors - this is the price, reliability and versatility of settings and programming. Thus, free programmable controllers of the PCD2-PCD3 series by Saia-Burgess were chosen for independent work in the central heating station and for data transmission. The domestic SCADA system Trace Mode 6 was chosen to create a control room. For data transmission, it was decided to use conventional cellular communication: use a conventional voice channel for data transmission and SMS messages to promptly notify personnel of emergency situations.
What is the working principle of the system
and features of the implementation of control in Trace Mode?
As in many similar systems, management functions for direct impact on regulatory mechanisms are given to the lower level, and the management of the entire system as a whole is transferred to the upper one. I deliberately omit the description of the work of the lower level (controllers) and the process of data transfer and will go straight to the description of the upper one.
For ease of use, the control room is equipped with a personal computer (PC) with two monitors. Data from all points are collected on the dispatch controller and transmitted via the RS-232 interface to the OPC server running on a PC. The project is implemented in Trace Mode version 6 and is designed for 2048 channels. This is the first stage of the implementation of the described system.
A feature of the implementation of the task in Trace Mode is an attempt to create a multi-window interface with the ability to monitor the process of heat supply in on-line mode, both on the city diagram and on the mnemonic diagrams of heat points. The use of a multi-window interface allows solving the problems of displaying a large amount of information on the dispatcher's display, which should be sufficient and at the same time non-redundant. The principle of a multi-window interface allows access to any process parameters in accordance with the hierarchical structure of windows. It also simplifies the implementation of the system at the facility, since such an interface is very similar in appearance to the widespread products of the Microsoft family and has similar menu equipment and toolbars familiar to any user of a personal computer.
On fig. 1 shows the main screen of the system. It schematically displays the main heating network with an indication of the heat source (CHP) and central heating points (from the first to the seventh). The screen displays information about the occurrence of emergency situations at the facilities, the current outdoor air temperature, the date and time of the last data transfer from each point. Heat supply objects are provided with pop-up hints. When an abnormal situation occurs, the object on the diagram begins to “blink”, and an event record and a red flashing indicator appear in the alarm report next to the date and time of data transmission. It is possible to view the enlarged thermal parameters for the CHP and for the entire heating network as a whole. To do this, disable the display of the list of the report of alarms and warnings (button "OTiP").
Rice. 1. Main screen of the system. Scheme of the location of heat supply facilities in the city of Velsk
There are two ways to switch to the mnemonic diagram of a heat point - you need to click on the icon on the city map or on the button with the heat point inscription.
The mnemonic diagram of the substation opens on the second screen. This is done both for the convenience of monitoring a specific situation at the central heating station, and for monitoring the general state of the system. On these screens, all controlled and adjustable parameters are visualized in real time, including parameters that are read from heat meters. All technological equipment and measuring instruments are provided with pop-up hints in accordance with the technical documentation.
The image of equipment and automation means on the mnemonic diagram is as close as possible to the real view.
At the next level of the multi-window interface, you can directly control the heat transfer process, change settings, view the characteristics of operating equipment, and monitor parameters in real time with a history of changes.
On fig. 2 shows a screen interface for viewing and managing the main automation tools (control controller and heat meter). On the controller management screen, it is possible to change telephone numbers for sending SMS messages, prohibit or allow the transmission of emergency and information messages, control the frequency and amount of data transmission, and set parameters for self-diagnostics of measuring instruments. On the screen of the heat meter, you can view all settings, change available settings and control the mode of data exchange with the controller.
Rice. 2. Control screens for the Vzlet TSRV heat calculator and PCD253 controller
On fig. 3 shows pop-up panels for control equipment (control valve and pump groups). It displays the current status of this equipment, error details and some parameters needed for self-diagnosis and verification. So, for pumps, dry-running pressure, MTBF and start-up delay are very important parameters.
Rice. 3. Control panel for pump groups and control valve
On fig. 4 shows screens for monitoring parameters and control loops in graphical form with the ability to view the history of changes. All controlled parameters of the heat substation are displayed on the parameters screen. They are grouped according to their physical meaning (temperature, pressure, flow, amount of heat, heat output, lighting). All control loops of parameters are displayed on the screen of control loops and the current value of the parameter is displayed, given the dead zone, the position of the valve and the selected control law. All this data on the screens is divided into pages, similar to the generally accepted design in Windows applications.
Rice. 4. Screens for graphic display of parameters and control loops
All screens can be moved across the space of two monitors while performing multiple tasks at the same time. All necessary parameters for trouble-free operation of the heat distribution system are available in real time.
How long has the system been in development?how many developers were there?
The basic part of the dispatching and control system in Trace Mode was developed within one month by the author of this article and launched in the city of Velsk. On fig. a photograph is presented from the temporary control room, where the system is installed and is undergoing trial operation. At the moment, our organization is putting into operation one more heating point and an emergency source of heat. It is at these facilities that a special control room is being designed. After its commissioning, all eight heat points will be included in the system.
Rice. 5. Temporary dispatcher's workplace
During the operation of the automated process control system, various comments and wishes from the dispatching service arise. Thus, the process of updating the system is constantly underway to improve the operational properties and convenience of the dispatcher.
What is the effect of introducing such a management system?
Advantages and disadvantages
In this article, the author does not set the task of assessing the economic effect of the introduction of a management system in numbers. However, the savings are obvious due to the reduction of personnel involved in the maintenance of the system, a significant reduction in the number of accidents. In addition, the environmental impact is obvious. It should also be noted that the introduction of such a system allows you to quickly respond and eliminate situations that may lead to unforeseen consequences. The payback period for the entire complex of works (construction of a heating main and heating points, installation and commissioning, automation and dispatching) for the customer will be 5-6 years.
The advantages of a working control system can be given:
Visual presentation of information on the graphic image of the object;
As for the animation elements, they were added to the project in a special way to improve the visual effect of viewing the program.
Prospects for the development of the system