Automatic heat supply control systems. With the use of modern automation equipment Equipment and automatic control of heat supply

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 complete solution for creating unified system management of urban systems of heat and water supply. 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 receiving thermal energy from the central heating station and providing 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, it is the economic effect that 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 we are talking about a major overhaul of a heat supply system of a non-optimal structure, 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 bears fixed costs, the structure of which is as follows:

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. Current values differential pressure compensate for the pressure 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 heating 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 costs 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 constraint functions entail deviations from comfortable conditions, and their application must have 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).

Article 18. Distribution of heat load and management of heat supply systems

1. The distribution of the heat load of consumers of thermal energy in the heat supply system between those supplying thermal energy in this heat supply system is carried out by the body authorized in accordance with this federal law for approval of the heat supply scheme, by making annual changes to the heat supply scheme.

2. To distribute the heat load of consumers of heat energy, all heat supply organizations that own sources of heat energy in this heat supply system are required to submit to the body authorized in accordance with this Federal Law to approve the heat supply scheme, an application containing information:

1) on the amount of heat energy that the heat supply organization undertakes to supply to consumers and heat supply organizations in this heat supply system;

2) on the amount of capacity of thermal energy sources, which the heat supply organization undertakes to support;

3) on current tariffs in the field of heat supply and predicted specific variable costs for the production of thermal energy, heat carrier and power maintenance.

3. In the heat supply scheme, conditions must be determined under which it is possible to supply thermal energy to consumers from various sources of thermal energy while maintaining the reliability of heat supply. In the presence of such conditions, the distribution of heat load between sources of heat energy is carried out on a competitive basis in accordance with the criterion of minimum specific variable costs for the production of thermal energy by sources of thermal energy, determined in accordance with the procedure established by the pricing bases in the field of heat supply, approved by the Government Russian Federation, on the basis of applications from organizations that own sources of thermal energy, and standards taken into account when regulating tariffs in the field of heat supply for the corresponding period of regulation.

4. If the heat supply organization does not agree with the distribution of the heat load carried out in the heat supply scheme, it has the right to appeal against the decision on such distribution, taken by the body authorized in accordance with this Federal Law to approve the heat supply scheme, to the federal executive body authorized by the Government of the Russian Federation.

5. Heat supply organizations and heat network organizations operating in the same heat supply system, annually before the start of the heating period, are required to conclude an agreement between themselves on the management of the heat supply system in accordance with the rules for organizing heat supply, approved by the Government of the Russian Federation.

6. The subject of the agreement specified in part 5 of this article is the procedure for mutual actions to ensure the functioning of the heat supply system in accordance with the requirements of this Federal Law. The obligatory conditions of this agreement are:

1) determining the subordination of dispatching services of heat supply organizations and heat network organizations, the procedure for their interaction;

3) the procedure for ensuring access of the parties to the agreement or, by mutual agreement of the parties to the agreement, to another organization to heat networks for the adjustment of heat networks and regulation of the operation of the heat supply system;

4) the procedure for interaction between heat supply organizations and heat network organizations in emergency situations and emergencies.

7. If the heat supply organizations and heat network organizations have not concluded the agreement specified in this article, the procedure for managing the heat supply system is determined by the agreement concluded for the previous heating period, and if such an agreement has not been concluded earlier, the specified procedure is established by the body authorized in accordance with this Federal law for approval of the heat supply scheme.

important public service in modern cities is heat supply. The heat supply system serves to meet the needs of the population in heating services for residential and public buildings, hot water supply (water heating) and ventilation.

The modern urban heat supply system includes the following main elements: a heat source, heat transmission networks and devices, as well as heat-consuming equipment and devices - heating, ventilation and hot water supply systems.

City heating systems are classified according to the following criteria:

• - degree of centralization;
• - type of coolant;
• - method of generating thermal energy;
• - method of supplying water for hot water supply and heating;
• - the number of pipelines of heating networks;
• - a way to provide consumers with thermal energy, etc.

By degree of centralization heat supply distinguish two main types:

• 1) centralized heat supply systems, which have been developed in cities and districts with predominantly multi-storey buildings. Among them are: highly organized centralized heat supply based on the combined generation of heat and electricity at CHP - district heating and district heating from district heating and industrial heating boilers;
• 2) decentralized heat supply from small adjoining boiler plants (attached, basement, roof), individual heating devices, etc.; at the same time, there are no heating networks and associated losses of thermal energy.

By coolant type Distinguish between steam and water heating systems. In steam heating systems, superheated steam acts as a heat carrier. These systems are mainly used for technological purposes in industry, power industry. For the needs of communal heat supply of the population due to the increased danger during their operation, they are practically not used.

In water heating systems, the heat carrier is hot water. These systems are used mainly for supplying thermal energy to urban consumers, for hot water supply and heating, and in some cases for technological processes. In our country, water heating systems account for more than half of all heating networks.

By method of generating heat energy distinguish:

• - Combined generation of heat and electricity at combined heat and power plants. In this case, the heat of the working thermal steam is used to generate electricity when the steam expands in the turbines, and then the remaining heat of the exhaust steam is used to heat water in the heat exchangers that make up the heating equipment of the CHP. Hot water is used for heating urban consumers. Thus, in a CHP plant, high-potential heat is used to generate electricity, and low-potential heat is used to supply heat. This is the energy meaning of the combined generation of heat and electricity, which provides a significant reduction in the specific fuel consumption in the production of heat and electricity;
• - separate generation of thermal energy, when heating water in boiler plants (thermal power plants) is separated from the generation of electrical energy.

By water supply method for hot water supply, water heating systems are divided into open and closed. In open water heating systems, hot water is supplied to the taps of the local hot water supply system directly from the heating networks. In closed water heating systems, water from heating networks is used only as a heating medium for heating in water heaters - heat exchangers (boilers) of tap water, which then enters the local hot water supply system.

By number of pipelines There are single-pipe, two-pipe and multi-pipe heat supply systems.

By way to provide consumers with thermal energy, single-stage and multi-stage heat supply systems are distinguished - depending on the schemes for connecting subscribers (consumers) to heating networks. The nodes for connecting heat consumers to heating networks are called subscriber inputs. At the subscriber input of each building, hot water heaters, elevators, pumps, fittings, instrumentation are installed to regulate the parameters and flow of the coolant according to local heating and water fittings. Therefore, often a subscriber input is called a local heating point (MTP). If a subscriber input is being constructed for a separate facility, then it is called an individual heating point (ITP).

When organizing single-stage heat supply systems, heat consumers are connected directly to heat networks. Such a direct connection of heating devices limits the limits of permissible pressure in heating networks, since high pressure necessary for the transport of the coolant to end consumers is dangerous for heating radiators. Because of this, single-stage systems are used to supply heat to a limited number of consumers from boiler houses with a short length of heating networks.

In multistage systems, between the heat source and consumers, central heating centers (CHP) or control and distribution points (CDP) are placed, in which the parameters of the coolant can be changed at the request of local consumers. The central heating and distribution centers are equipped with pumping and water heating units, control and safety fittings, instrumentation designed to provide a group of consumers in a quarter or district with thermal energy of the required parameters. With the help of pumping or water heating installations, main pipelines (first stage) are partially or completely hydraulically isolated from distribution networks (second stage). From the CHP or KRP, a heat carrier with acceptable or established parameters is supplied through common or separate pipelines of the second stage to the MTP of each building for local consumers. At the same time, only elevator mixing of return water from local heating installations, local regulation of water consumption for hot water supply and metering of heat consumption are carried out in the MTP.

The organization of complete hydraulic isolation of heat networks of the first and second stages is the most important measure for improving the reliability of heat supply and increasing the range of heat transport. Multi-stage heat supply systems with central heating and distribution centers allow reducing the number of local hot water heaters, circulation pumps and temperature controllers installed in the MTP with a single-stage system by a factor of ten. In the central heating center, it is possible to organize the treatment of local tap water to prevent corrosion of hot water supply systems. Finally, during the construction of the central heating and distribution centers, the unit operating costs and the costs of maintaining personnel for servicing equipment in the MTP are significantly reduced.

Thermal energy in the form of hot water or steam is transported from a CHP or boiler house to consumers (residential buildings, public buildings and industrial enterprises) through special pipelines - heating networks. The route of heat networks in cities and other settlements should be provided in the technical lanes allocated for engineering networks.

Modern heating networks of urban systems are complex engineering structures. Their length from the source to consumers is tens of kilometers, and the diameter of the mains reaches 1400 mm. The structure of thermal networks includes heat pipelines; compensators that perceive temperature elongations; disconnecting, regulating and safety equipment installed in special chambers or pavilions; pumping stations; district heating points (RTP) and heating points (TP).

Heating networks are divided into main, laid in the main directions locality, distribution - within the quarter, microdistrict - and branches to individual buildings and subscribers.

Schemes of thermal networks are used, as a rule, beam. In order to avoid interruptions in the supply of heat to the consumer, individual main networks are connected to each other, as well as the installation of jumpers between branches. In large cities, in the presence of several large heat sources, more complex heat networks are built according to the ring scheme.

To ensure the reliable functioning of such systems, their hierarchical construction is necessary, in which the entire system is divided into a number of levels, each of which has its own task, decreasing in value from the top level to the bottom. The upper hierarchical level is made up of heat sources, the next level is main heating networks with RTP, the lower one is distribution networks with subscriber inputs of consumers. Heat sources supply hot water of a given temperature and a given pressure to the heating networks, ensure the circulation of water in the system and maintain the proper hydrodynamic and static pressure in it. They have special water treatment plants, where chemical cleaning and water deaeration. The main heat carrier flows are transported through the main heat networks to the heat consumption nodes. In the RTP, the coolant is distributed among the districts, autonomous hydraulic and thermal regimes are maintained in the networks of the districts. The organization of the hierarchical construction of heat supply systems ensures their controllability during operation.

To control the hydraulic and thermal modes of the heat supply system, it is automated, and the amount of heat supplied is regulated in accordance with consumption standards and subscriber requirements. The largest amount of heat is spent on heating buildings. The heating load changes with the outside temperature. To maintain the conformity of heat supply to consumers, it uses central regulation on heat sources. achieve High Quality heat supply, using only central regulation, is not possible, therefore, additional automatic regulation is used at heating points and at consumers. The water consumption for hot water supply is constantly changing, and in order to maintain a stable heat supply, the hydraulic mode of heat networks is automatically regulated, and the temperature of hot water is maintained constant and equal to 65 ° C.

The main systemic problems that complicate the organization of an effective mechanism for the functioning of heat supply in modern cities include the following:

• - significant physical and moral wear and tear of equipment of heat supply systems;
• - high level losses in heat networks;
• - massive lack of heat energy meters and heat supply regulators among residents;
• - overestimated thermal loads of consumers;
• - imperfection of normative-legal and legislative base.

The equipment of thermal power plants and heating networks has a high degree of wear on average in Russia, reaching 70%. The total number of heating boiler houses is dominated by small, inefficient ones, the process of their reconstruction and liquidation proceeds very slowly. The increase in thermal capacities annually lags behind the increasing loads by 2 times or more. Due to systematic interruptions in the provision of boiler fuel in many cities, serious difficulties annually arise in the heat supply of residential areas and houses. The start-up of heating systems in the fall stretches for several months; winter period become the norm, not the exception; the rate of equipment replacement is declining, the number of equipment in disrepair is increasing. This predetermined in recent years a sharp increase in the accident rate of heat supply systems.

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

The issues of introducing resource-saving technologies in modern Russia given considerable attention. 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 than in the central regions of the country, 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 means management to ensure economic efficiency work 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 the urgent 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.

Solution of optimal control problems technological processes 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 Program for Importing 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 designed for it software made it possible to solve a wide range of reconstruction tasks at the 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 control of technological processes of 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 automated system dispatching control and management of central heating points and pumping stations (ASDKiU TsTPiNS), to 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 question organization of parallel operation of sources (TS) - determination of factors that have a significant impact on the load of boiler houses, and the tasks of the heat supply control system to provide consumers with the necessary amount of thermal energy at the lowest possible cost for its generation and transmission.

The solution of the first problem is carried out by linking the supply schedules with the schedules for the use of heat through a system of heat exchangers, the solution of the second - 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) to the 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 3 311 312 313 3 14

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 signaling parameters are displayed on the trends and mnemonic diagrams of the operator station; all information

PC workstation of the dispatcher

Adapter SHV/K8-485

Dedicated telephone 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 multi-level 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 zone 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 for integrating control subsystems, as well as building an effective human-machine interface focused on a person (dispatcher). At the same time, the transfer of the functions of the dispatcher for data analysis, forecasting situations and making appropriate decisions to the components of intelligent systems for supporting decision making and execution (SSPIR) is envisaged. 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 supports a natural language user interface with a ZAOA 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

1. Shubin E.P. The main issues of designing urban heat supply systems. M.: Energy, 1979. 360 p.

2. Prokhorenkov A.M. Reconstruction of heating boiler houses on the basis of information and control complexes // Nauka proizvodstvo. 2000. No. 2. S. 51-54.

3. Prokhorenkov A.M., Sovlukov A.S. Fuzzy models in control systems of boiler aggregate technological processes // Computer Standards & Interfaces. 2002 Vol. 24. P. 151-159.

4. Mesarovich M., Mako D., Takahara Y. Theory of hierarchical multilevel systems. M.: Mir, 1973. 456 p.

5. Prokhorenkov A.M. Methods for identification of random process characteristics in information processing systems // IEEE Transactions on instrumentation and measurement. 2002 Vol. 51, N° 3. P. 492-496.

6. Prokhorenkov A.M., Kachala H.M. Random Signal Processing in Digital Industrial Control Systems // Digital Signal Processing. 2008. No. 3. S. 32-36.

7. Prokhorenkov A.M., Kachala N.M. Determination of the classification characteristics of random processes // Measurement Techniques. 2008 Vol. 51, No. 4. P. 351-356.

8. Prokhorenkov A.M., Kachala H.M. Influence of classification characteristics of random processes on the accuracy of processing measurement results // Izmeritelnaya tekhnika. 2008. N° 8. S. 3-7.

9. Prokhorenkov A.M., Kachala N.M., Saburov I.V., Sovlukov A.S. Information system for analysis of random processes in nonstationary objects // Proc. of the Third IEEE Int. Workshop on Intelligent Data Acquisition and Advanced Computing Systems: Technology and Applications (IDAACS "2005). Sofia, Bulgaria. 2005. P. 18-21.

10. Methods of Robust Neuro-Fuzzy and Adaptive Control, Ed. N.D. Yegupova // M.: Publishing house of MSTU im. N.E. Bauman, 2002". 658 p.

P. Prokhorenkov A.M., Kachala N.M. Effectiveness of adaptive algorithms for tuning regulators in control systems subjected to the influence of random disturbances // BicrniK: Scientific and Technical. well. Special issue. Cherkasy State Technol. un-t.-Cherkask. 2009. S. 83-85.

12. Prokhorenkov A.M., Saburov I.V., Sovlukov A.S. Data maintenance for processes of decision-making under industrial control // BicrniK: scientific and technical. well. Special issue. Cherkasy State Technol. un-t. Cherkask. 2009. S. 89-91.

As part of the supply of switchboard equipment, power cabinets and control cabinets for two buildings (ITP) were supplied. For the reception and distribution of electricity in heating points, input-distributing devices are used, consisting of five panels each (10 panels in total). Switching switches, surge arresters, ammeters and voltmeters are installed in the input panels. ATS panels in ITP1 and ITP2 are implemented on the basis of automatic transfer units. In the distribution panels of the ASU, protection and switching devices (contactors, soft starters, buttons and lamps) are installed for the technological equipment of heating points. All circuit breakers are equipped with status contacts signaling an emergency shutdown. This information is transmitted to the controllers installed in the automation cabinets.

To control and manage the equipment, OWEN PLC110 controllers are used. They are connected to the input / output modules ARIES MV110-224.16DN, MV110-224.8A, MU110-224.6U, as well as operator touch panels.

The coolant is introduced directly into the ITP room. Water supply for hot water supply, heating and heat supply of air heaters of air ventilation systems is carried out with a correction according to the outside air temperature.

The display of technological parameters, accidents, equipment status and dispatch control of the ITP is carried out from the workstation of dispatchers in the integrated central control room of the building. On the dispatching server, the archive of technological parameters, accidents, and the state of the ITP equipment is stored.

Automation of heat points provides for:

• maintaining the temperature of the coolant supplied to the heating and ventilation systems in accordance with the temperature schedule;
• maintaining the temperature of the water in the DHW system at the supply to consumers;
• programming of various temperature regimes by hours of the day, days of the week and holidays;
• control of compliance with the values ​​of parameters determined by the technological algorithm, support of technological and emergency parameters limits;
• temperature control of the heat carrier returned to the heating network of the heat supply system, according to a given temperature schedule;
• outside air temperature measurement;
• maintaining a given pressure drop between the supply and return pipelines of ventilation and heating systems;
• control of circulation pumps according to a given algorithm:
  • on/off;
  • control of pumping equipment with frequency drives according to signals from PLC installed in automation cabinets;
  • periodic switching main / reserve to ensure the same operating time;
  • automatic emergency transfer to the standby pump according to the control of the differential pressure sensor;
  • automatic maintenance of a given differential pressure in heat consumption systems.
• control of heat carrier control valves in primary consumer circuits;
• control of pumps and valves for feeding circuits of heating and ventilation;
• setting the values ​​of technological and emergency parameters through the dispatching system;
• control of drainage pumps;
• control of the state of electrical inputs by phases;
• synchronization of the controller time with the common time of the dispatching system (SOEV);
• start-up of equipment after restoration of power supply in accordance with a given algorithm;
• sending emergency messages to the dispatching system.

Information exchange between automation controllers and the upper level (workstation with specialized MasterSCADA dispatching software) is carried out using the Modbus/TCP protocol.