Flexible regulation and control method for achieving dynamic heat storage and release of heat supply system

Abstract

The invention discloses a flexible regulation and control method for realizing dynamic heat storage and release of a heat supply system, which comprises the following steps of: firstly, selecting a part of heating stations as bypass heating stations and the other heating stations as non-bypass heating stations according to requirements; the primary side of the heat exchange unit of the bypass heating station is provided with a primary side bypass pipe and a bypass electric regulating valve; the primary side of the heat exchange unit of the non-bypass heating station is not provided with a primary side bypass pipe and a bypass electric regulating valve; secondly, according to the determined number and positions of the bypass heating stations, the heat source and the bypass heating stations serve as boundaries, and the connected graph of the first-level water supply pipe network is topologically decomposed into a plurality of sub-connected graphs; and finally, on the basis of the divided sub-connected graphs, the heating station is regulated and controlled, and flexible dynamic heat storage and release of the primary network can be achieved through partial hydraulic decoupling regulation and control.

Description

Technical Field

[0001] The present invention relates to the field of heating, and in particular to a flexible control method for realizing dynamic heat storage and release of a heating system. Background Art

[0002] With the continuous construction and development of renewable energy (wind power, photovoltaic power, etc.), the demand for peak load regulation of the power grid is increasing. As the basic heat source of the central heating system, the cogeneration unit has gradually switched from the "heat-to-electricity" operation mode to the "electricity-to-heat" operation mode. Due to the volatility of renewable energy supply, the heat supply of the central heating system is no longer stable, and the imbalance between heat supply and demand has intensified.

[0003] By configuring heat storage bypass pipes and heat storage electric regulating valves on the primary side of certain key thermal power stations in the primary network, the high-temperature heat medium in the primary network water supply pipe can be directly input into the return network, thereby increasing the primary return water temperature and further utilizing the heat storage potential of the heat medium in the primary return network, significantly increasing the total heat storage capacity of the primary network while taking into account the investment cost of the project, thus increasing the heat storage capacity and taking into account the economy.

[0004] The realization of dynamic heat storage and release in the primary grid relies on advanced and reliable control strategies and methods. The main problems faced in the control process are as follows:

[0005] (1) For any heating station in the centralized heating system, when the primary water supply temperature changes, supply and demand balance control based on the primary heat exchange electric regulating valve is required. However, the local supply and demand balance control of a certain heating station will affect the pressure and flow distribution of the entire primary network, and interfere with the supply and demand balance of other heating stations, resulting in other heating stations also having to implement corresponding supply and demand balance control. At the same time, the delay time for the heat medium to be transmitted from the heat source to each heating station is not equal. Therefore, the local supply and demand balance control of each heating station is not synchronized, and there is a complex coupling between the control actions. On the whole, the control process of the centralized heating system is unstable and prone to oscillation. In addition, the actuator operates frequently and the service life is reduced.

[0006] (2) The dynamic heat storage and release of the primary network lacks simple, reliable and effective control strategies and methods. Summary of the invention

[0007] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is to provide a flexible control method for realizing dynamic heat storage and release of a heating system.

[0008] The technical solution of the present invention to solve the technical problem is to provide a flexible control method for realizing dynamic heat storage and release of a heating system, characterized in that the method comprises the following steps:

[0009] Step 1: Continuously replenish water and set pressure at the inlet of the heat source main circulation pump; at the same time, compare the heat source outlet pressure Phs and the set value P of the heat source outlet pressure hs,set , implement constant pressure difference control based on frequency conversion of main circulation pump at the heat source;

[0010] Step 2: According to the demand, select some thermal power stations as bypass thermal power stations, and the rest of the thermal power stations as non-bypass thermal power stations; the primary side of the heat exchanger unit of the bypass thermal power station is equipped with a primary side bypass pipe and a bypass electric regulating valve; the primary side of the heat exchanger unit of the non-bypass thermal power station is not equipped with a primary side bypass pipe and a bypass electric regulating valve;

[0011] The secondary network water supply temperature sensor measures the secondary network water supply temperature t of the bypass thermal power station in real time p,g And transmit it to the PLC controller; combine historical and real-time outdoor meteorological parameters, historical and real-time room temperature monitoring data, weather forecast data, and room temperature setting target value to calculate the secondary network water supply temperature setting value t of the bypass thermal power station p,g,set , which is input through the operating parameter input module and transmitted to the PLC controller; the operating parameter input module inputs the primary side design pressure difference ΔP of the bypass thermal power station p,set And transmit it to the PLC controller; the pressure difference sensor measures the primary side supply and return water pressure of the bypass thermal power station in real time through the high-pressure end probe and the low-pressure end probe, and then obtains the primary side supply and return water pressure difference ΔP of the bypass thermal power station p And transmit it to the PLC controller;

[0012] The secondary network water supply temperature sensor measures the secondary network water supply temperature T of the non-bypass thermal power station in real time f,g And transmit it to the PLC controller; combine historical and real-time outdoor meteorological parameters, historical and real-time room temperature monitoring data, weather forecast data, and room temperature setting target value to calculate the secondary network water supply temperature setting value T of the non-bypass thermal power station f,g,set , input through the operation parameter input module and transmitted to the PLC controller;

[0013] Step 3, division of sub-connectivity graphs: according to the number and location of the bypass thermal power stations determined in step 2, the connectivity graph of the primary water supply network is topologically decomposed into multiple sub-connectivity graphs with the heat source and the bypass thermal power station as the boundary; the boundary of each sub-connectivity graph is the bypass thermal power station or the heat source, and the remaining internal thermal power stations are all non-bypass thermal power stations;

[0014] Step 4: Based on the sub-connected graph divided in step 3, control the thermal power station:

[0015] Working condition 1: When the primary side water supply temperature of a bypass thermal power station in the primary network changes, the bypass thermal power station is subject to supply and demand balance regulation based on the primary side heat exchange electric regulating valve and constant pressure difference regulation based on the bypass electric regulating valve; other thermal power stations in the primary network are not regulated;

[0016] Operating condition 2: When the primary side water supply temperature of a non-bypass thermal power station in the primary network changes, the supply and demand balance regulation of the non-bypass thermal power station based on the primary side heat exchange electric regulating valve is first performed on this non-bypass thermal power station; then, the supply and demand balance regulation of the non-bypass thermal power station based on the primary side heat exchange electric regulating valve is also performed on all other non-bypass thermal power stations in the sub-connected graph to which this non-bypass thermal power station belongs, and the bypass thermal power station at the boundary of the sub-connected graph to which this non-bypass thermal power station belongs is performed with the constant pressure difference regulation based on the bypass electric regulating valve in operating condition 1; all thermal power stations outside the sub-connected graph to which this non-bypass thermal power station belongs are not regulated.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) The present invention configures a primary bypass pipe and a bypass electric regulating valve on the primary side of some thermal power stations, takes the heat source and the bypass thermal power station as the boundary, and obtains a sub-connectivity graph by topological decomposition of the primary water supply network connectivity graph. Based on this, a heating system control method is proposed, which can realize flexible dynamic heat storage and release of the primary network through partial hydraulic decoupling control.

[0019] (2) The dynamic heat storage and release of the primary network in the centralized heating system is achieved with the help of multiple independent local feedback controls (supply and demand balance control of all thermal power stations and constant pressure difference control of bypass thermal power stations). The control strategy is simple and stable, and easy to implement in engineering applications.

[0020] (3) Installing bypass in some thermal power stations can reduce initial investment and operating costs, especially for those thermal power stations with low flow demand or small heating demand (the flow rate that can be bypassed in thermal power stations with low flow demand or small heating demand is also small, which has little impact on the heat storage effect).

[0021] (4) The interference of the supply and demand balance control of the non-bypass thermal power station on the hydraulic conditions of the primary network is limited to the sub-connected graph to which the station belongs. The coupling interference between independent local feedback controls is significantly reduced, the stability of the system control process is enhanced, the actuator action frequency is reduced, and the life span is extended. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the heat exchange system of the bypass thermal power station of the present invention;

[0023] Figure 2 It is a structural schematic diagram of a heat exchange system of a non-bypass thermal power station of the present invention;

[0024] Figure 3 It is a topological decomposition diagram of the primary water supply network connectivity diagram of the present invention;

[0025] Figure 4 A topological decomposition diagram of a primary water supply network connectivity diagram of Example 1 of the present invention;

[0026] Figure 5 The first-level network water pressure diagram of time period A in the reference working condition or dynamic heat storage process of Example 1 of the present invention;

[0027] Figure 6 It is the water pressure diagram of the primary network in time period B and time period C of Example 1 of the present invention;

[0028] Figure 7 It is the water pressure diagram of the primary network in time period D and time period E of Example 1 of the present invention.

[0029] In the figure, there are heat exchanger unit 1, primary side water supply pipe 2, primary side return pipe 3, secondary side water supply pipe 4, secondary side return pipe 5, primary side heat exchange electric regulating valve 6, secondary network circulation pump 7, secondary network water supply temperature sensor 8, PLC controller 9, bypass electric regulating valve 10, primary side bypass pipe 11, high pressure end probe 12, low pressure end probe 13, differential pressure sensor 14, and operation parameter input module 15. DETAILED DESCRIPTION

[0030] The specific embodiments of the present invention are given below. The specific embodiments are only used to further illustrate the present invention in detail and do not limit the protection scope of the present invention.

[0031] The present invention provides a flexible control method for realizing dynamic heat storage and release of a heating system (hereinafter referred to as the method), characterized in that the method comprises the following steps:

[0032] Step 1: Continuously replenish water and set pressure at the inlet of the heat source main circulation pump; at the same time, compare the heat source outlet pressure P hs and the set value P of the heat source outlet pressure hs,set , implement constant pressure difference control based on frequency conversion of main circulation pump at the heat source;

[0033] Preferably, in step 1, the constant pressure difference control based on the frequency conversion of the main circulation pump is specifically: when P hs <P hs,set -δ1, increase the operating frequency of the primary network main circulation pump; when P hs >P hs,set +δ1, reduce the operating frequency of the primary network main circulation pump; when P hs,set -δ1≤P hs ≤P hs,set +δ1, the operating frequency of the primary network main circulation pump is maintained constant; δ1 is the dead zone range of constant pressure difference control at the primary network heat source, Pa.

[0034] Step 2: According to the demand, some thermal power stations are selected as bypass thermal power stations, and the rest of the thermal power stations are non-bypass thermal power stations; the primary side of the heat exchanger unit 1 of the bypass thermal power station is equipped with a primary side bypass pipe 11 and a bypass electric regulating valve 10; the primary side of the heat exchanger unit 1 of the non-bypass thermal power station is not equipped with a primary side bypass pipe 11 and a bypass electric regulating valve 10;

[0035] The secondary network water supply temperature sensor 8 measures the secondary network water supply temperature t of the bypass thermal power station in real time p,g And transmit it to the PLC controller 9; combine historical and real-time outdoor meteorological parameters, historical and real-time room temperature monitoring data, weather forecast data, and room temperature setting target value to calculate the secondary network water supply temperature setting value t of the bypass thermal power station p,g,set , is input through the operating parameter input module 15 and transmitted to the PLC controller 9; the operating parameter input module 15 inputs the primary side design pressure difference ΔP of the bypass thermal power station p,set And transmit it to the PLC controller 9; the pressure difference sensor 14 measures the primary side supply and return water pressure of the bypass thermal power station in real time through the high-pressure end probe 12 and the low-pressure end probe 13, and then obtains the primary side supply and return water pressure difference ΔP of the bypass thermal power station p And transmit it to the PLC controller 9;

[0036] The secondary network water supply temperature sensor 8 measures the secondary network water supply temperature T of the non-bypass thermal power station in real time. f,g And transmit it to the PLC controller 9; combine historical and real-time outdoor meteorological parameters, historical and real-time room temperature monitoring data, weather forecast data, and room temperature setting target value to calculate the secondary network water supply temperature setting value T of the non-bypass thermal power station f,g,set , input through the operating parameter input module 15 and transmitted to the PLC controller 9;

[0037] Preferably, in step 2, the heat exchange system of the thermal power station (such as Figure 1 The heat exchange unit 1 includes a primary water supply pipe 2, a primary water return pipe 3, a secondary water supply pipe 4, a secondary water return pipe 5, a primary heat exchange electric regulating valve 6, a secondary network circulation pump 7, a secondary network water supply temperature sensor 8, a PLC controller 9, a bypass electric regulating valve 10, a primary bypass pipe 11, a high-pressure end probe 12, a low-pressure end probe 13, a differential pressure sensor 14 and an operation parameter input module 15;

[0038] A high-pressure end probe 12 is installed on the primary water supply pipe 2; a primary heat exchange electric regulating valve 6 and a low-pressure end probe 13 are installed on the primary water return pipe 3 in sequence according to the fluid flow direction; the starting end of the primary bypass pipe 11 is connected to the primary water supply pipe 2, and is located downstream of the high-pressure end probe 12 according to the fluid flow direction; the end of the primary bypass pipe 11 is connected to the primary water return pipe 3, and is located between the primary heat exchange electric regulating valve 6 and the low-pressure end probe 13; a bypass electric regulating valve 10 is installed on the primary bypass pipe 11; a secondary network water supply temperature sensor 8 is installed on the secondary water supply pipe 4; a secondary network circulation pump 7 is installed on the secondary water return pipe 5;

[0039] The high-pressure end probe 12 and the low-pressure end probe 13 are both communicatively connected to the differential pressure sensor 14; the PLC controller 9 is communicatively connected to the primary side heat exchange electric regulating valve 6, the secondary network water supply temperature sensor 8, the bypass electric regulating valve 10, the differential pressure sensor 14 and the operation parameter input module 15 respectively.

[0040] Preferably, in step 2, the heat exchange system of the non-bypass thermal power station (such as Figure 2 ) includes a heat exchange unit 1, a primary water supply pipe 2, a primary water return pipe 3, a secondary water supply pipe 4, a secondary water return pipe 5, a primary heat exchange electric regulating valve 6, a secondary network circulation pump 7, a secondary network water supply temperature sensor 8, a PLC controller 9 and an operation parameter input module 15;

[0041] A primary side heat exchange electric regulating valve 6 is installed on the primary side return water pipe 3; a secondary network water supply temperature sensor 8 is installed on the secondary side supply water pipe 4; a secondary network circulation pump 7 is installed on the secondary side return water pipe 5; and the PLC controller 9 is respectively communicated with the primary side heat exchange electric regulating valve 6, the secondary network water supply temperature sensor 8 and the operation parameter input module 15.

[0042] Preferably, in step 2, the starting end of the primary water supply pipe 2 is used to input a primary high-temperature water supply heat medium, and the end is connected to the primary heat medium inlet of the heat exchanger unit 1; the starting end of the primary return water pipe 3 is connected to the primary heat medium outlet of the heat exchanger unit 1, and the end is used to output a primary low-temperature return water heat medium; the starting end of the secondary water supply pipe 4 is connected to the secondary heat medium outlet of the heat exchanger unit 1, and the end is used to output the secondary water supply heat medium; the end of the secondary return water pipe 5 is connected to the secondary heat medium inlet of the heat exchanger unit 1, and the starting end is used to input the secondary return water heat medium.

[0043] Step 3, division of sub-connectivity graphs: according to the number and location of the bypass thermal power stations determined in step 2, with the heat source and the bypass thermal power station as the boundaries of the sub-connectivity graph, the connectivity graph of the primary water supply network (the connectivity graph of the primary water supply network is used to characterize the topological connection relationship between all water supply pipes in the primary network of the centralized heating system) is topologically decomposed into multiple sub-connectivity graphs; the boundaries of each sub-connectivity graph are the bypass thermal power station or the heat source, and the remaining internal thermal power stations are all non-bypass thermal power stations;

[0044] Preferably, in step 3, Figure 3 As shown in the figure, the heat source and the first bypass thermal power station are used as boundaries to form the first sub-connected graph (i.e., sub-connected Figure 1 ); the last bypass thermal power station and the last thermal power station are used as boundaries to form the last sub-connected graph (i.e., sub-connected graph k+1).

[0045] Step 4: Based on the sub-connected graph divided in step 3, control the thermal power station:

[0046] Working condition 1: when the primary side water supply temperature of a bypass thermal power station in the primary network changes, the bypass thermal power station is subject to supply and demand balance control based on the primary side heat exchange electric regulating valve 6 (hereinafter referred to as supply and demand balance control of the bypass thermal power station) and constant pressure difference control based on the bypass electric regulating valve 10 (hereinafter referred to as constant pressure difference control); other thermal power stations in the primary network are not regulated;

[0047] Preferably, in step 4, in working condition 1, the supply and demand balance control of the bypass thermal power station is performed by the PLC controller 9 according to t p,g and t p,g,set The difference between the values ​​of and sends a command to the primary side heat exchange electric regulating valve 6 to adjust the opening, thereby adjusting the heat medium flow entering the heat exchange unit 1. Specifically:

[0048] When t p,g >t p,g,set +δ 2,p When the temperature of the secondary network water supply temperature sensor 8 is lowered, the PLC controller 9 reduces the opening of the primary side heat exchange electric regulating valve 6, reduces the heat medium flow entering the heat exchange unit 1, and makes the t p,g Reduce and meet t p,g,set -δ 2,p ≤t p,g ≤t p,g,set +δ 2,p ;

[0049] When t p,g,set -δ 2,p ≤t p,g ≤t p,g,set +δ 2,p When the opening of the primary side heat exchange electric regulating valve 6 is maintained constant;

[0050] When t p,g <t p,g,set -δ 2,p When the temperature of the secondary network water supply temperature sensor 8 is lower than that of the primary side heat exchange electric regulating valve 6, the PLC controller 9 increases the opening of the primary side heat exchange electric regulating valve 6, increases the heat medium flow entering the heat exchange unit 1, and makes the t p,g Increase and meet t p,g,set -δ 2,p ≤t p,g ≤t p,g,set+δ 2,p ;

[0051] Among them, δ 2,p Dead zone range for supply and demand balance control of bypass thermal power station, ℃.

[0052] Preferably, in step 4, in working condition 1, the constant pressure difference is regulated by the PLC controller 9 according to ΔP p and ΔP p,set The difference between the values ​​of is used to send a command to the bypass electric regulating valve 10 to adjust the opening, specifically:

[0053] When ΔP p >ΔP p,set +δ3, the bypass electric regulating valve 10 is opened or the opening is increased. Since the heat medium flows directly into the primary return pipe 3 through the primary bypass pipe 11 without heat exchange, the temperature of the heat medium in the primary return pipe 3 will increase, so heat will be stored in the heat medium in the primary return pipe 3;

[0054] When ΔP p,set -δ3≤ΔP p ≤ΔP p,set When +δ3, the opening of bypass electric regulating valve 10 is maintained constant;

[0055] When ΔP p <ΔP p,set -δ3, close or reduce the opening of the bypass electric regulating valve 10. At this time, since there is no heat medium in the primary side bypass pipe 11 or the heat medium flow rate is reduced, the temperature of the heat medium in the primary side return pipe 3 will decrease, so the heat stored in advance will be released;

[0056] Among them, δ3 is the dead zone range of the bypass thermal station constant pressure difference control, Pa.

[0057] Operating condition 2: When the primary side water supply temperature of a non-bypass thermal power station in the primary network changes, the supply and demand balance regulation of the non-bypass thermal power station based on the primary side heat exchange electric regulating valve 6 (referred to as the supply and demand balance regulation of the non-bypass thermal power station) is first performed on this non-bypass thermal power station; then, the supply and demand balance regulation of the non-bypass thermal power station based on the primary side heat exchange electric regulating valve 6 is also performed on all other non-bypass thermal power stations in the sub-connected graph to which this non-bypass thermal power station belongs, and the bypass thermal power station at the boundary of the sub-connected graph to which this non-bypass thermal power station belongs is performed according to operating condition 1. All thermal power stations outside the sub-connected graph to which this non-bypass thermal power station belongs are not regulated.

[0058] Preferably, in step 4, in operating condition 2, the supply and demand balance control of the non-bypass thermal power station is performed by the PLC controller 9 according to T f,g and T f,g,set The difference between the values ​​of the primary heat exchange electric regulating valve 6 sends a command to adjust the opening, specifically:

[0059] When T f,g >T f,g,set +δ 2,f When the opening of the primary side heat exchange electric regulating valve 6 is reduced;

[0060] When T f,g,set -δ 2,f ≤T f,g ≤T p,f,set +δ 2,f When the opening of the primary side heat exchange electric regulating valve 6 is maintained constant;

[0061] When T f,g <T f,g,set -δ 2,f When the opening of the primary side heat exchange electric regulating valve 6 is increased;

[0062] Among them, δ 2,f Dead zone range for supply and demand balance control of non-bypass thermal power station, ℃.

[0063] Embodiment 1:

[0064] (1) Setting of calculation conditions:

[0065] like Figure 4 As shown in the figure, there are four heating stations in a certain level network, of which heating stations 1 and 3 are non-bypass heating stations, and heating stations 2 and 4 are bypass heating stations. With the heat source and the two bypass heating stations as the boundaries, the connectivity graph can be topologically decomposed into two sub-connectivity graphs, namely, sub-connectivity graphs. Figure Ⅰ Connect with sub Figure II The actual heat exchange flow rate of No. 1 thermal power station is expressed as G h1 , the primary water supply pressure is expressed as P g,1 , the primary return water pressure is expressed as P h,1 ; The actual heat exchange flow rate of No. 2 thermal power station is expressed as G h2 , the actual bypass flow is expressed as G p2 , the primary water supply pressure is expressed as P g,2 , the primary return water pressure is expressed as P h,2 ; The actual heat exchange flow rate of No. 3 thermal power station is expressed as G h3 , the primary water supply pressure is expressed as P g,3 , the primary return water pressure is expressed as P h,3 ; The actual heat exchange flow rate of No. 4 thermal power station is expressed as G h4 , the actual bypass flow is expressed as G p4 , the primary water supply pressure is expressed as P g,4 , the primary return water pressure is expressed as P h,4 ; The water supply pressure of the heat source is expressed as P g,0 , the return water pressure is expressed as P h,0 .

[0066] Taking the operating condition when the pipe network is not storing or releasing heat as the benchmark operating condition, it is assumed that the heat exchange flow rate of the four thermal power stations under the benchmark operating condition is 10t / h, and the bypass flow rate of thermal power station No. 2 and thermal power station No. 4 is 0t / h. The water pressure diagram under the benchmark operating condition is as follows Figure 5 As shown, under the benchmark operating conditions, P g,0 and P h,0 They are 100kPa and 0kPa respectively. The pressure losses of pipe sections 1 to 4 are all 5. The primary side reference pressure differences of thermal power stations No. 1 to 4 are 90kPa, 80kPa, 70kPa and 60kPa respectively. The primary side supply and return water pressures of thermal power station No. 1 are 95kPa and 5kPa respectively, the primary side supply and return water pressures of thermal power station No. 2 are 90kPa and 10kPa respectively, the primary side supply and return water pressures of thermal power station No. 3 are 85kPa and 15kPa respectively, and the primary side supply and return water pressures of thermal power station No. 4 are 80kPa and 20kPa respectively.

[0067] (2) Dynamic heat storage process of the primary network:

[0068] During the heat storage process of the primary network, the temperature of the heat medium at the heat source outlet increases, and it starts from the heat source and arrives at the No. 1 heat station, No. 2 heat station, No. 3 heat station and No. 4 heat station in turn. Assume that at the beginning of heat storage, the high-temperature heat medium starts from the heat source and flows through pipe section 1 before reaching the No. 1 heat station. The time period is A, the time period from the No. 1 heat station to the No. 2 heat station through pipe section 2 is B, the time period from the No. 2 heat station to the No. 3 heat station through pipe section 3 is C, the time period from the No. 3 heat station to the No. 4 heat station through pipe section 4 is D, and the time period after reaching the No. 4 heat station is E. The actual heat exchange flow, actual bypass flow, primary side water supply pressure and primary side return water pressure of time periods A to E can be calculated. The specific meaning of time period AE is shown in Table 1.

[0069] Table 1

[0070] Time period meaning A The high-temperature heat medium starts from the heat source and flows in pipe section 1 before reaching the No. 1 thermal power station; B The high-temperature heat medium starts from the No. 1 heat station, flows in the pipe section 2, and arrives before the No. 2 heat station; C The high-temperature heat medium starts from the No. 2 heat station, flows in the pipe section 3, and arrives before the No. 3 heat station; D The high-temperature heat medium starts from the No. 3 heat station, flows in the pipe section 4, and arrives before the No. 4 heat station; E After the high-temperature heat medium arrives at Thermal Station No. 4.

[0071] Time period A: Before the high-temperature heat medium arrives at the No. 1 heat station, the heat stations are in a state of supply and demand balance, that is, the heat supply meets the heat demand, and the primary side heat exchange electric regulating valve 6 and bypass electric regulating valve 10 of each heat station do not adjust, and the water pressure diagram of the pipe network remains Figure 5 In the state shown, the actual heat exchange flow and actual bypass flow of each thermal power station are 10t / h and 0t / h respectively.

[0072] Time period B: When the high-temperature heat medium arrives at the No. 1 thermal power station, the primary side water supply temperature of the No. 1 thermal power station rises. As a non-bypass thermal power station, the supply and demand balance regulation is implemented. The primary side heat exchange electric regulating valve 6 of the No. 1 thermal power station is adjusted so that G h1Reduced to 8t / h; as a connector Figure Ⅰ The boundary bypass thermal power station, the No. 2 thermal power station simultaneously implements constant pressure difference control, the bypass electric regulating valve 10 of the No. 2 thermal power station is opened to maintain the primary side pressure difference of the No. 2 thermal power station at 80kPa, so G p2 The main circulation pump is increased to 0.8432t / h, and the main circulation pump is controlled by variable frequency constant pressure difference. The operating conditions of the No. 3 and No. 4 thermal power stations outside the sub-connection diagram I are not disturbed, so the primary side heat exchange electric regulating valve 6 and bypass electric regulating valve 10 of the No. 3 and No. 4 thermal power stations do not adjust. The water pressure diagram is as follows Figure 6 As shown, P g,0 , P h,0 , P g,2 and P h,2 Due to the constant pressure difference control, both remain unchanged. Since the flow rate in pipe section 1 decreases from 40t / h to 38.8432t / h, and the resistance coefficient of pipe section 1 remains unchanged, P g,1 From 95kPa to 95.25kPa, P h,1 From 5kPa to 4.71kPa, the primary side pressure difference (P g,1 -P h,1 ) increases.

[0073] Time period C: When the high-temperature heat medium reaches the No. 2 thermal power station, the primary side water supply temperature of the No. 2 thermal power station rises. As a bypass thermal power station, supply and demand balance regulation and constant pressure difference regulation should be implemented. The primary side heat exchange electric regulating valve 6 and bypass electric regulating valve 10 of the No. 2 thermal power station should be adjusted to make G h2 and G p2 The water pressure diagram of the primary network has not changed, and the operating conditions of the No. 1, No. 3 and No. 4 thermal power stations are not disturbed. Figure 6 shown.

[0074] Time period D: When the high-temperature heat medium reaches the No. 3 thermal power station, the primary side water supply temperature of the No. 3 thermal power station rises. As a non-bypass thermal power station, the No. 3 thermal power station implements supply and demand balance regulation and adjusts the primary side heat exchange electric regulating valve 6 of the No. 3 thermal power station so that G h3 As the boundary bypass thermal power station of sub-connection diagram II, the bypass electric regulating valve 10 of thermal power station No. 2 and thermal power station No. 4 is synchronously adjusted to implement constant pressure difference regulation, G p2 and G p4 Adjusted to 4.2056t / h and 0.6376t / h respectively. Figure II The No. 1 thermal power station is not regulated. Its water pressure diagram is as follows Figure 7 As shown in Figure 2, since the flow rate in pipe section 3 is reduced from 20 t / h to 18.64 t / h, and the resistance coefficient of pipe section 1 remains unchanged, P g,3From 85kPa to 85.66kPa, P h,3 From 15kPa to 14.341kPa, the primary side pressure difference (P g,3 -P h,3 ) increases.

[0075] Time period E: When the high-temperature heat medium reaches the No. 4 thermal power station, the primary side water supply temperature of the No. 4 thermal power station rises. As a bypass thermal power station, the No. 4 thermal power station implements supply and demand balance regulation and constant pressure difference regulation, and adjusts the primary side heat exchange electric regulating valve 6 and bypass electric regulating valve 10 of the No. 4 thermal power station so that G h4 and G p4 The water pressure diagram is still the same as Figure 7 shown.

[0076] Table 2 Flow changes of each pipe section in the primary network during the process of high-temperature heat medium from heat source to end user

[0077]

[0078] Any matters not described in the present invention are applicable to the prior art.

Claims

1. A flexible control method for realizing dynamic heat storage and release of a heating system, characterized in that: The method comprises the following steps: Step 1: Continuously replenish water and set pressure at the inlet of the heat source main circulation pump; at the same time, compare the heat source outlet pressure P hs and the set value P of the heat source outlet pressure hs,set , implement constant pressure difference control based on frequency conversion of main circulation pump at the heat source; Step 2: According to the demand, some of the thermal power stations are selected as bypass thermal power stations, and the remaining thermal power stations are non-bypass thermal power stations; the primary side of the heat exchanger unit (1) of the bypass thermal power station is equipped with a primary side bypass pipe (11) and a bypass electric regulating valve (10); the primary side of the heat exchanger unit (1) of the non-bypass thermal power station is not equipped with a primary side bypass pipe (11) and a bypass electric regulating valve (10); The secondary network water supply temperature sensor (8) measures the secondary network water supply temperature t of the bypass thermal power station in real time p,g and transmit it to the PLC controller (9); combining historical and real-time outdoor meteorological parameters, historical and real-time room temperature monitoring data, weather forecast data, and room temperature setting target value to calculate the secondary network water supply temperature setting value t of the bypass thermal power station p,g,set , is input through the operation parameter input module (15) and transmitted to the PLC controller (9); the operation parameter input module (15) inputs the primary side design pressure difference ΔP of the bypass thermal power station p,set The pressure difference sensor (14) measures the primary side supply and return water pressure of the bypass thermal power station in real time through the high-pressure end probe (12) and the low-pressure end probe (13), thereby obtaining the primary side supply and return water pressure difference ΔP of the bypass thermal power station. p And transmit it to the PLC controller (9); The secondary network water supply temperature sensor (8) measures the secondary network water supply temperature T of the non-bypass thermal power station in real time. f,g and transmit it to the PLC controller (9); combining historical and real-time outdoor meteorological parameters, historical and real-time room temperature monitoring data, weather forecast data, and room temperature setting target value to calculate the secondary network water supply temperature setting value T of the non-bypass thermal power station f,g,set , input through the operating parameter input module (15) and transmitted to the PLC controller (9); Step 3, division of sub-connectivity graphs: according to the number and location of the bypass thermal power stations determined in step 2, the connectivity graph of the primary water supply network is topologically decomposed into multiple sub-connectivity graphs with the heat source and the bypass thermal power station as the boundary; the boundary of each sub-connectivity graph is the bypass thermal power station or the heat source, and the remaining internal thermal power stations are all non-bypass thermal power stations; Step 4: Based on the sub-connected graph divided in step 3, control the thermal power station: Working condition 1: when the primary side water supply temperature of a bypass thermal power station in the primary network changes, the bypass thermal power station is subjected to supply and demand balance regulation based on the primary side heat exchange electric regulating valve (6) and constant pressure difference regulation based on the bypass electric regulating valve (10); other thermal power stations in the primary network are not regulated; Working condition 2: when the primary side water supply temperature of a non-bypass thermal power station in the primary network changes, the supply and demand balance control of the non-bypass thermal power station based on the primary side heat exchange electric regulating valve (6) is first performed on this non-bypass thermal power station; then, the supply and demand balance control of the non-bypass thermal power station based on the primary side heat exchange electric regulating valve (6) is also performed on all other non-bypass thermal power stations in the sub-connected graph to which this non-bypass thermal power station belongs, and the constant pressure difference control based on the bypass electric regulating valve (10) of working condition 1 is performed on the bypass thermal power station at the boundary of the sub-connected graph to which this non-bypass thermal power station belongs; all thermal power stations outside the sub-connected graph to which this non-bypass thermal power station belongs are not controlled.

2. The flexible control method for realizing dynamic heat storage and release of a heating system according to claim 1 is characterized in that: In step 1, the constant pressure difference control based on the frequency conversion of the main circulation pump is as follows: hs <P hs,set -δ1, increase the operating frequency of the primary network main circulation pump; when P hs >P hs,set +δ1, reduce the operating frequency of the primary network main circulation pump; when P hs,set -δ1≤P hs ≤P hs,set +δ1, the operating frequency of the primary network main circulation pump is maintained constant; δ1 is the dead zone range of constant pressure difference control at the primary network heat source.

3. The flexible control method for realizing dynamic heat storage and release of a heating system according to claim 1 is characterized in that: In step 2, the heat exchange system of the bypass thermal power station includes a heat exchange unit (1), a primary side water supply pipe (2), a primary side water return pipe (3), a secondary side water supply pipe (4), a secondary side water return pipe (5), a primary side heat exchange electric regulating valve (6), a secondary network circulation pump (7), a secondary network water supply temperature sensor (8), a PLC controller (9), a bypass electric regulating valve (10), a primary side bypass pipe (11), a high pressure end probe (12), a low pressure end probe (13), a differential pressure sensor (14) and an operation parameter input module (15); A high-pressure end probe (12) is installed on the primary water supply pipe (2); a primary heat exchange electric regulating valve (6) and a low-pressure end probe (13) are installed on the primary water return pipe (3) in sequence according to the fluid flow direction; the starting end of the primary bypass pipe (11) is connected to the primary water supply pipe (2) and is located downstream of the high-pressure end probe (12) according to the fluid flow direction; the end of the primary bypass pipe (11) is connected to the primary water return pipe (3) and is located between the primary heat exchange electric regulating valve (6) and the low-pressure end probe (13); a bypass electric regulating valve (10) is installed on the primary bypass pipe (11); a secondary network water supply temperature sensor (8) is installed on the secondary water supply pipe (4); and a secondary network circulation pump (7) is installed on the secondary water return pipe (5); The high-pressure end probe (12) and the low-pressure end probe (13) are both communicatively connected to the differential pressure sensor (14); the PLC controller (9) is communicatively connected to the primary-side heat exchange electric regulating valve (6), the secondary network water supply temperature sensor (8), the bypass electric regulating valve (10), the differential pressure sensor (14) and the operation parameter input module (15).

4. The flexible control method for realizing dynamic heat storage and release of a heating system according to claim 1 is characterized in that: In step 2, the heat exchange system of the non-bypass thermal power station includes a heat exchange unit (1), a primary side water supply pipe (2), a primary side water return pipe (3), a secondary side water supply pipe (4), a secondary side water return pipe (5), a primary side heat exchange electric regulating valve (6), a secondary network circulation pump (7), a secondary network water supply temperature sensor (8), a PLC controller (9) and an operation parameter input module (15); A primary side heat exchange electric regulating valve (6) is installed on the primary side return water pipe (3); a secondary network water supply temperature sensor (8) is installed on the secondary side supply water pipe (4); a secondary network circulation pump (7) is installed on the secondary side return water pipe (5); and a PLC controller (9) is respectively connected to the primary side heat exchange electric regulating valve (6), the secondary network water supply temperature sensor (8) and the operation parameter input module (15) for communication.

5. The flexible control method for realizing dynamic heat storage and release of a heating system according to claim 3 or 4, characterized in that: In step 2, the starting end of the primary water supply pipe (2) is used to input a primary high-temperature water supply heat medium, and the end is connected to the primary heat medium inlet of the heat exchange unit (1); the starting end of the primary water return pipe (3) is connected to the primary heat medium outlet of the heat exchange unit (1), and the end is used to output a primary low-temperature return water heat medium; the starting end of the secondary water supply pipe (4) is connected to the secondary heat medium outlet of the heat exchange unit (1), and the end is used to output the secondary water supply heat medium; the end of the secondary water return pipe (5) is connected to the secondary heat medium inlet of the heat exchange unit (1), and the starting end is used to input the secondary return water heat medium.

6. The flexible control method for realizing dynamic heat storage and release of a heating system according to claim 1 is characterized in that: In step 4, in operating condition 1, the supply and demand balance control of the bypass thermal power station is performed by the PLC controller (9) according to t p,g and t p,g,set The difference between the values ​​of the first and second heat exchangers sends a command to the primary side heat exchange electric regulating valve (6) to adjust the opening, thereby adjusting the heat medium flow entering the heat exchange unit (1), specifically: When t p,g >t p,g,set +δ 2,p When the PLC controller (9) reduces the opening of the primary side heat exchange electric regulating valve (6), the heat medium flow entering the heat exchange unit (1) is reduced, and the t p,g Reduce and meet t p,g,set -δ 2,p ≤t p,g ≤t p,g,set +δ 2,p ; When t p,g,set -δ 2,p ≤t p,g ≤t p,g,set +δ 2,p When the opening of the primary side heat exchange electric regulating valve (6) is maintained constant; When t p,g <t p,g,set -δ 2,p When the PLC controller (9) increases the opening of the primary side heat exchange electric regulating valve (6), the heat medium flow entering the heat exchange unit (1) is increased, and the t p,g Increase and meet t p,g,set -δ 2,p ≤t p,g ≤t p,g,set +δ 2,p ; Among them, δ 2,p It is the dead zone range for the supply and demand balance regulation of the bypass thermal power station.

7. The flexible control method for realizing dynamic heat storage and release of a heating system according to claim 1 is characterized in that: In step 4, in working condition 1, the constant pressure difference is controlled by the PLC controller (9) according to ΔP p and ΔP p,set The difference between the values ​​of the bypass electric regulating valve (10) sends a command to adjust the opening, specifically: When ΔP p >ΔP p,set +δ3, the bypass electric regulating valve (10) is opened or the opening is increased. Since the heat medium flows directly into the primary return pipe (3) through the primary bypass pipe (11) without heat exchange, the temperature of the heat medium in the primary return pipe (3) will increase, so heat will be stored in the heat medium in the primary return pipe 3; When ΔP p,set -δ3≤ΔP p ≤ΔP p,set When +δ3, the opening of the bypass electric regulating valve (10) is maintained constant; When ΔP p <ΔP p,set -δ3, the bypass electric regulating valve (10) is closed or the opening is reduced. At this time, since there is no heat medium in the primary side bypass pipe (11) or the heat medium flow rate is reduced, the temperature of the heat medium in the primary side return pipe (3) will decrease, thereby releasing the heat stored in advance; Among them, δ3 is the dead zone range of the bypass thermal station constant pressure difference control.

8. The flexible control method for realizing dynamic heat storage and release of a heating system according to claim 1, characterized in that: In step 4, in operating condition 2, the supply and demand balance control of the non-bypass thermal power station is controlled by the PLC controller (9) according to T f,g and T f,g,set The difference between the values ​​of is used to send a command to the primary side heat exchange electric regulating valve (6) to adjust the opening, specifically: When T f,g >T f,g,set +δ 2,f When the temperature is high, the opening of the primary side heat exchange electric regulating valve (6) is reduced; When T f,g,set -δ 2,f ≤T f,g ≤T p,f,set +δ 2,f When the opening of the primary side heat exchange electric regulating valve (6) is maintained constant; When T f,g <T f,g,set -δ 2,f When the opening of the primary side heat exchange electric regulating valve (6) is increased; Among them, δ 2,f It is the dead zone range for supply and demand balance control of non-bypass thermal power station.

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