Control method and system for improving peak-shaving capability of thermal power units

Abstract

The present invention discloses a control method and system for improving the peak-shaving capacity of a thermal power unit. The control method for improving the peak-shaving capacity of a thermal power unit includes determining whether the thermal power unit is operating at peak load or deep load. If not, the steam extraction rate for external heat supply from the thermal power unit is increased, and the heat corresponding to the excess steam is stored. If so, the steam extraction rate for external heat supply from the thermal power unit is reduced, and the stored heat is released to provide heat to users. This method enables the unit to meet power generation needs when peak operation is required, and to meet heating needs when deep load operation is required.

Description

Technical Field

[0001] The present invention relates to the technical field of peak-shaving and heat supply operation of thermal power units, and more specifically, to a control method for improving the peak-shaving capability of thermal power units. Furthermore, the present invention also relates to a system applicable to the control method for improving the peak-shaving capability of thermal power units. Background Art

[0002] Large thermal power plants typically use condensing steam turbines with adjustable extraction and heating capabilities for external heat supply. Some units have undergone low-pressure cylinder removal to improve heating capacity. Heating is typically provided by exhaust steam from the intermediate-pressure cylinders, which is routed to the heater steam pipeline, which then connects to the heat network heaters. Heating extraction is regulated by the unit's steam turbine digital electro-hydraulic control system. Heat network heater drains flow through the heat network heater drain pumps and into the deaerator. The external heat supply system utilizes a main pipe system, with supply and return pipes connected to the external heat network. Multiple heat network heaters and circulating water pumps are typically installed.

[0003] Part of the steam generated by boiler evaporation enters the steam turbine to perform work, and part is extracted from the steam turbine to supply external heat. When the steam generated by boiler evaporation is constant, the sum of the electrical load and the external heat supply is also fixed. At this time, only the electrical load and the external heat supply are distributed. On the one hand, for condensing units, the external heat supply can be adjusted to zero and used entirely for power supply; it can also be adjusted to maximum. The maximum heat supply is limited by factors such as the real-time evaporation capacity of the boiler, the structure of the steam turbine unit, and the extraction design. For example, when a 200MW thermal power unit is operating in condensing conditions and the boiler evaporation capacity is maximum (600t / h), the maximum extraction capacity of the middle exhaust for external heat supply is approximately 320t / h.

[0004] At this point, if further increases in extraction steam are needed, low-pressure cylinder trimming is necessary to reduce the amount of steam entering the low-pressure cylinders to a minimum, allowing the excess steam to be used for external heat supply. For example, a 200MW thermal power unit operating with low-pressure cylinder trimming can increase the external heat extraction steam capacity by approximately 100 t / h. Regardless of whether the unit is operating in condensing or trimming conditions, steam must enter the steam turbine to generate work for external heat extraction, generating electrical power. Therefore, there is a certain relationship between electrical power and external heat extraction steam capacity. Generally, the greater the demand for external heat extraction steam, the greater the electrical power.

[0005] Currently, with increasing heating demand and heating area, the external heat supply of thermal power units continues to increase. Due to the influence of thermal-electric coupling, the increase in external heat supply limits the peak-shaving capacity of the units. For example, when the units need to operate at peak load (high load), the increased external heat supply demand leaves the units with less capacity for power generation. However, when the units need to operate at low load (deep regulation), the electrical load of the units cannot drop too low to maintain the minimum heat supply demand.

[0006] In summary, how to ensure that the unit can meet the power generation demand when it needs to operate at peak speed and meet the heating demand when it needs to operate at deep adjustment is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0007] In light of this, the present invention aims to provide a control method for improving the peak-shaving capacity of thermal power units, enabling the units to meet power generation needs when peak operation is required, while also meeting heating needs when deep regulation is required. Another object of the present invention is to provide a system for applying the aforementioned control method for improving the peak-shaving capacity of thermal power units.

[0008] In order to achieve the above object, the present invention provides the following technical solutions:

[0009] A control method for improving the peak-shaving capability of a thermal power unit, comprising:

[0010] Determine whether the thermal power unit is in peak operation or deep regulation operation. If not, increase the steam extraction amount of the thermal power unit for external heat supply and store the heat corresponding to the excess steam extraction amount;

[0011] If so, the steam extraction amount of the thermal power unit for external heat supply is reduced, and the stored heat is released to provide heating to users.

[0012] Preferably, the step of increasing the amount of steam extracted by the thermal power unit for external heat supply and storing the heat corresponding to the excess steam extraction includes:

[0013] Increase the amount of steam extracted for external heat supply of the thermal power unit, and control the primary side water inlet regulating valve of each thermal power station in the thermal network to gradually decrease;

[0014] Determine the corresponding relationship between the maximum external heat extraction steam capacity Lb of the thermal power unit and the electric power Gb of the thermal power unit to obtain a unit dispatch curve;

[0015] Determine the external heat extraction steam shortage Lq when the thermal power unit is in peak operation or deep adjustment operation according to the unit dispatch curve;

[0016] According to the unit dispatch curve, before the thermal power unit is in peak operation or deep adjustment operation, the heat corresponding to the steam extraction shortfall Lq for external heat supply is stored in the thermal network;

[0017] The heat storage amount of the heat pipe network and the heat storage amount of the energy-saving building are determined according to the stored heat, and the heat pipe network and the energy-saving building are used to store heat in coordination.

[0018] Preferably, the heat storage of the heat pipe network and the heat storage of the energy-saving building are determined based on the stored heat, and the heat storage of the heat pipe network and the energy-saving building are used in combination, including:

[0019] Determine the shortage of steam extraction for external heating L q Is it less than the maximum storage capacity L of the thermal network? qDmax , if so, select some heating stations of the heating network for heat storage;

[0020] If not, the heat pipe network and energy-saving building are selected to store heat together.

[0021] Preferably, the step of selecting some of the heating stations in the heating network for heat storage includes:

[0022] According to the maximum heat storage capacity of the bypass of each thermal power station, select from large to small to determine the thermal power station for heat storage;

[0023] The bypass of the heat storage station is controlled to be opened wide, so that part of the hot water returns to the return pipe of the heat network to complete the heat storage process of the heat network. Preferably, the control of the bypass of the heat storage station is controlled to be opened wide, including:

[0024] The bypass of the thermal power station with heat storage is controlled and determined to be opened gradually in the order of the near end, the middle end and the far end.

[0025] Preferably, the selection of the thermal network and the energy-saving building to jointly store heat includes:

[0026] The maximum storage capacity L of the thermal network is stored qDmax The heat corresponding to the steam is stored in the energy-saving building to supply heat to the outside world. q With maximum storage capacity L qDmax The heat corresponding to the difference in steam.

[0027] Preferably, the energy-saving building is used to store the gap of external heat extraction steam L q With maximum storage capacity L qDmax The heat corresponding to the difference in steam includes:

[0028] Select all energy-saving buildings for heat storage, and on the basis of proportional distribution according to the maximum heat storage capacity of each energy-saving building, use the building insulation level coefficient k to correct the heat storage capacity of each energy-saving building;

[0029] The primary side water inlet regulating valve of the thermal power station in each energy-saving building is controlled not to be reduced, or even opened wider, to complete the heat storage process of the energy-saving building.

[0030] Preferably, the releasing of stored heat to provide heating to users includes:

[0031] Determining a heat storage method of the thermal network;

[0032] If the heat storage method is to select some of the heating stations in the heat network for heat storage, the bypass of each heating station that has not stored heat is controlled to remain closed, the primary side water inlet regulating valve of each heating station that has not stored heat is controlled to gradually increase, and the bypass of each heating station that has stored heat is controlled to reduce, so that the hot water stored in advance enters the heat network for use by users;

[0033] If the heat storage method is to select the thermal network and energy-saving buildings to store heat together, then the thermal stations storing heat are controlled to reduce the bypass so that the hot water stored in advance enters the thermal network, and the primary side water inlet regulating valve of each energy-saving building is controlled not to increase or even to decrease.

[0034] A system, applied to any of the above control methods for improving the peak-shaving capability of a thermal power unit, comprising:

[0035] Thermal power units;

[0036] A heat pipe network connected to the thermal power unit;

[0037] The control device is connected to the thermal power unit and the thermal pipe network. The control device is used to determine whether the thermal power unit is in peak operation or deep adjustment operation. If not, the steam extraction amount of the thermal power unit for external heat supply is increased, and the heat corresponding to the excess steam extraction amount is stored; if so, the steam extraction amount of the thermal power unit for external heat supply is reduced, and the stored heat is released to provide heating to users.

[0038] Preferably, the heat pipe network includes a heat network head station, a heat network circulation pump and multiple heat stations;

[0039] The thermal power unit is connected to the input end of the heating network first station, and the output end of the heating network first station is provided with the heating network circulation pump. The heating network circulation pump, the thermal power station and the other input end of the heating network first station are connected in sequence to form a loop. The thermal network includes multiple parallel loops.

[0040] When using the control method provided by the present invention for improving the peak-shaving capacity of a thermal power unit, it is determined whether the thermal power unit is in peak operation or deep regulation operation. If the thermal power unit is not in peak operation or deep regulation operation, the thermal power unit is subjected to heat storage operation in advance, that is, the external heat extraction steam volume of the thermal power unit can be increased, and the heat corresponding to the excess steam extraction volume is stored. When the thermal power unit is in peak operation or deep regulation operation, the heat stored in advance is released, that is, the external heat extraction steam volume of the thermal power unit can be reduced, and the previously stored heat is used to provide heat to the user, so as to realize the reuse of the stored heat, thereby ensuring that when the thermal power unit is in peak operation (high load operation), the external heat supply demand of the thermal power unit will not be too large, resulting in the thermal power unit having no more capacity for power generation, and also ensuring that when the thermal power unit is in deep regulation operation (low load operation), the minimum heat supply demand can be maintained to avoid the unit's electrical load from dropping too low.

[0041] In summary, the control method for improving the peak-shaving capability of a thermal power unit provided by the present invention can enable the unit to meet power generation needs when peak operation is required, and can also enable the unit to meet heating needs when deep regulation operation is required.

[0042] In addition, the present invention also provides a system applied to the above-mentioned control method for improving the peak-shaving capability of a thermal power unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0044] Figure 1 A flow chart of a control method for improving the peak-shaving capability of a thermal power unit provided by the present invention;

[0045] Figure 2 This is a schematic diagram of the structure of the system provided by the present invention.

[0046] Figure 1-Figure 2 middle:

[0047] 1 is the thermal power unit, 2 is the first station of the heating network, 3 is the heating network circulation pump, Z1 is the first thermal power station, Z2 is the second thermal power station, Zp is the pth thermal power station, Zn is the nth thermal power station, Vl is the primary side water inlet regulating valve of the first thermal power station, V2 is the primary side water inlet regulating valve of the second thermal power station, V4 is the primary side water inlet regulating valve of the nth thermal power station, V3 is the bypass regulating valve of the second thermal power station, ta is the outlet water temperature of the first station of the heating network, tb is the return water temperature of the first station of the heating network, t1 is the primary side inlet water temperature of the first thermal power station, t2 is the primary network return water temperature of the first thermal power station, t3 is the primary network inlet water temperature of the second thermal power station, t5 is the primary network return water temperature of the second thermal power station, t4 is the bypass inlet water temperature of the second thermal power station, t6 is the primary network inlet water temperature of the nth thermal power station, and t7 is the primary network return water temperature of the nth thermal station. DETAILED DESCRIPTION

[0048] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0049] The core of this invention is to provide a control method for improving the peak-shaving capacity of thermal power units, enabling them to meet power generation needs when operating at peak power levels, and to meet heating needs when operating at lower power levels. Another core of this invention is to provide a system that applies this control method for improving the peak-shaving capacity of thermal power units.

[0050] Please refer to Figure 1 and Figure 2 , Figure 1 A flow chart of a control method for improving the peak-shaving capability of a thermal power unit provided by the present invention; Figure 2 This is a schematic diagram of the structure of the system provided by the present invention.

[0051] This specific embodiment provides a control method for improving the peak-shaving capability of a thermal power unit, including:

[0052] Determine whether the thermal power unit 1 is in peak operation or deep adjustment operation. If not, increase the steam extraction amount of the thermal power unit 1 for external heat supply and store the heat corresponding to the excess steam extraction amount;

[0053] If so, the steam extraction amount of the thermal power unit 1 for external heat supply is reduced, and the stored heat is released to provide heat to the user.

[0054] When using the control method for improving the peak-shaving capacity of a thermal power unit provided by the present invention, it is determined whether the thermal power unit 1 is in peak operation or deep regulation operation. If the thermal power unit 1 is not in peak operation or deep regulation operation, a heat storage operation is performed on the thermal power unit 1 in advance before the peak operation or deep regulation operation of the thermal power unit 1, that is, the external heat supply steam extraction amount of the thermal power unit 1 can be increased, and the heat corresponding to the steam of the excess extraction amount can be stored.

[0055] When the thermal power unit 1 is operating at peak load or deep adjustment, the heat stored in advance is released, that is, the amount of steam extracted for external heat supply of the thermal power unit 1 can be reduced, and the previously stored heat can be used to supply heat to users, so as to realize the reuse of the stored heat, thereby ensuring that during peak operation (high load operation), the external heat supply demand of the thermal power unit 1 will not be too large, resulting in the thermal power unit 1 having no more capacity for power generation. It can also ensure that when the thermal power unit 1 is operating at deep adjustment (low load operation), the minimum heat supply demand can be maintained to avoid the unit's electrical load from dropping too low.

[0056] In summary, the control method for improving the peak-shaving capability of a thermal power unit provided by the present invention can enable the unit to meet power generation needs when peak operation is required, and can also enable the unit to meet heating needs when deep regulation operation is required.

[0057] On the basis of the above embodiment, preferably, the amount of steam extracted by the thermal power unit 1 for external heat supply is increased, and the heat corresponding to the excess steam is stored, including:

[0058] 1. Increase the amount of steam extracted for external heat supply of thermal power unit 1, and gradually close the primary side water inlet regulating valve of each thermal power station in the thermal network.

[0059] It should be noted that increasing the amount of steam extracted from the thermal power unit 1 for external heat supply will gradually increase the primary side outlet water temperature of the heating network's first station 2. As the primary side outlet water temperature increases, the primary side (hot water side) inlet water temperature of each thermal power station will increase one by one according to the distance from the heating network's first station 2. At this time, the thermal power stations without bypass regulating valves do not need to perform bypass adjustment, while the bypass regulating valves of the thermal power stations with bypass regulating valves remain closed. The primary side inlet water regulating valves of each thermal power station are gradually closed by automatic control to reduce the flow of hot water entering the thermal power station, thereby ensuring that the heat absorption on the secondary side (cold water side) remains unchanged and that the heat used by users remains unchanged.

[0060] 2. Determine the maximum external heat extraction steam capacity L of thermal power unit 1 b The electric power G of thermal power unit 1 b The corresponding relationship is used to obtain the unit dispatch curve; that is, when the structure and extraction position of thermal power unit 1 are determined, the maximum external heat extraction steam capacity L b The electric power G of thermal power unit 1 bFor example, under the condensation condition of a 200MW thermal power unit 1, L b With G b The corresponding relationship is as follows:

[0061]

[0062] 3. According to the unit dispatch curve, determine the external heat extraction steam gap L when the thermal power unit 1 is running at peak or deep adjustment q ;

[0063] L q =k*(L a -L b )t fg (2)

[0064] Among them, L q L is the gap in steam extraction for external heat supply; a The demand for extraction steam for external heating can be determined based on the weather temperature when the number of heating users is certain; L b is the maximum external heat extraction steam capacity determined according to the unit dispatch curve, which can be determined by formula (1); t fg is the duration of deep adjustment operation or peak operation; k is the loss coefficient, which is generally 1-1.05.

[0065] For example, if the deep regulation load requirement of thermal power unit 1 is 80MW and the duration is 3 hours, the maximum external heat extraction steam capacity L can be determined according to formula (1): b is 135t / h. If the external heat extraction steam demand L a If the output is 150t / h, then there is a shortage of 15t / h of extraction steam for external heating. If the deep adjustment operation time of thermal power unit 1 is 3 hours and k is 1, the shortage of extraction steam for external heating can be obtained as L q It is 45t.

[0066] 4. According to the unit dispatch curve, before the peak operation or deep adjustment operation of thermal power unit 1, the shortage of external heat extraction steam L is stored in the thermal network. q The heat corresponding to the steam is stored in the thermal network in advance (heat storage process).

[0067]

[0068] Among them, t b is the heat storage process time. Since the unit dispatch curve is generally a point every 15 minutes, t b A total of 4t b Points, L bi It can be determined according to formula (1).

[0069] 5. Determine the heat storage capacity of the heat pipe network and the heat storage capacity of energy-saving buildings based on the stored heat, and use the heat pipe network and energy-saving buildings to store heat. Energy-saving buildings refer to building communities with better energy-saving and heat-insulating functions, and heat storage can be performed using the heat stations in these communities. For example, heat storage can be performed by adjusting the bypass of the heat pipe network or by adjusting the primary water inlet valve of the heat station in the energy-saving building community.

[0070]

[0071]

[0072] Among them, L qD is the amount of steam extracted and stored in the thermal network; m is the number of thermal stations that store heat through bypass adjustment, L qDi Heat storage for the i-th thermal power station; L qJ is the amount of steam extracted and stored in energy-saving buildings; n is the number of energy-saving buildings for heat storage, L qJi Heat storage for the i-th energy-saving building; L qDmax is the maximum amount of steam extracted to be stored in the thermal network, which is calculated by the following formula (7):

[0073]

[0074] Where p is the maximum number of thermal power stations that can be adjusted to store heat through bypass; L qDmaxi is the maximum bypass heat storage capacity of the i-th thermal power station.

[0075] That is, a portion of heat can be stored in the thermal network in advance (heat storage process). When the thermal power unit 1 needs to operate at peak power or deep adjustment, the heat supply from the thermal power unit 1 to the outside can be reduced, and the stored heat in the thermal network can be released to maintain the heating needs of heat users (heat release process). Furthermore, the good thermal insulation characteristics of energy-saving buildings can be utilized to release the heat storage capacity of energy-saving buildings.

[0076] Preferably, the heat storage of the heat pipe network and the heat storage of the energy-saving building are determined according to the stored heat, and the heat storage of the heat pipe network and the energy-saving building are used to store heat, including:

[0077] Determine the shortage of steam extraction for external heating L q Is it less than the maximum storage capacity L of the heat pipe network? qDmax , if so, select some heating stations in the heating network for heat storage;

[0078] If not, choose to store heat together with the heating pipe network and energy-saving buildings.

[0079] On the basis of the above embodiment, preferably, some heating stations in the heating network are selected for heat storage, including selecting from large to small according to the maximum bypass heat storage capacity of each heating station to determine the heating stations for heat storage; controlling the bypass of the heating station determined to store heat to open wide, so that part of the hot water returns to the return pipe of the heating network, thereby completing the heat storage process of the heating network.

[0080] By increasing the bypass of the heat storage station, some hot water is returned to the return pipe of the heat network, thereby increasing the return water temperature within the heat network pipes. The increase in the amount of steam extracted by thermal power unit 1 for external heat supply increases the temperature of the hot water within the heat network pipes, while the user's heat consumption remains unchanged. The excess heat is stored within the heat network pipes, completing the heat storage process within the heat network.

[0081] In addition, L is preferred qDmaxi The advantage of this is that the value of m is kept as small as possible, that is, the number of selected thermal power stations is minimized, the number of bypass valves opened is minimized, and the energy loss caused by the bypass valve is minimized.

[0082] Preferably, controlling and determining that the bypass of the heat storage thermal power station is opened wide includes controlling and determining that the bypass of the heat storage thermal power station is opened gradually in the order of the proximal end, the middle end and the distal end.

[0083] It should be noted that the basic principle for selecting some thermal power stations for heat storage is: give priority to thermal power stations that are farther away from the first heating station, have a larger heating area, and have thicker bypass pipes; the location of the thermal power station is mainly at the far end, followed by the middle end, and supplemented by the near end; after the thermal power station is selected, the bypass of the thermal power station is gradually opened in the order of the near end, the middle end, and the far end, so as to reduce the number of thermal power stations as much as possible and make the energy loss caused by the bypass valve as low as possible.

[0084] Preferably, the heat pipe network and energy-saving buildings are selected to store heat together, including using the heat pipe network to store the maximum storage capacity L qDmax The heat corresponding to the steam is stored in the energy-saving building to supply heat to the outside world. q With maximum storage capacity L qDmax That is, when the required heat storage capacity is large and only using the bypass to regulate the thermal network cannot meet the heat storage capacity requirements, energy-saving buildings can be used for heat storage.

[0085] Preferably, the energy-saving building is used to store the external heating steam extraction gap L q With maximum storage capacity L qDmaxThe heat corresponding to the difference in steam is stored by selecting all energy-saving buildings for heat storage. Based on a proportional allocation based on the maximum heat storage capacity of each energy-saving building, the heat storage capacity of each energy-saving building is corrected using the building insulation level coefficient k. The primary water inlet valve of the heating stations within each energy-saving building is maintained at a constant value, or even increased, to complete the energy-saving building heat storage process. When the steam extraction from thermal power unit 1 for external heating is increased, the primary water outlet temperature of the heating network's primary station 2 gradually increases. As the primary water outlet temperature rises, the primary water inlet temperature of each heating station increases accordingly based on its distance from the primary station 2. At this point, the primary water inlet valve of the heating stations within each energy-saving building area is maintained at a constant value, or even increased. This increases the primary water outlet temperature of the heating stations within the energy-saving building area, thereby increasing the heat absorption by the secondary side of the heating stations within the energy-saving building area, increasing the amount of heat entering the energy-saving buildings and completing the energy-saving building heat storage process. When it is necessary to select an energy-saving building for heat storage, the selection method is: allocate the heat storage amount according to the insulation level and heat storage capacity of the energy-saving building, and calculate it using the following formula (8):

[0086]

[0087] Among them, L qJmaxi is the maximum heat storage of the i-th energy-saving building; k i is the insulation level of the i-th energy-saving building, usually 1-2.

[0088] Therefore, the basic principle for selecting energy-saving buildings for heat storage is: select all energy-saving buildings for heat storage, and on the basis of proportional distribution according to the maximum heat storage capacity of each energy-saving building, use the building insulation level coefficient k for correction, that is, allocate more heat storage to energy-saving buildings with better insulation effects as much as possible.

[0089] It should be noted that before the thermal power unit 1 is in peak operation or deep adjustment operation, the heat storage process is carried out, which means that the amount of steam extracted by the thermal power unit 1 for external heat supply can be increased, and the primary side outlet water temperature of the first station 2 of the heating network can be gradually increased. As the primary side outlet water temperature increases, the primary side (hot water side) inlet water temperature of each thermal power station will increase one by one according to the distance from the first station 2 of the heating network. At this time, the thermal power stations without bypass regulating valves do not need to perform bypass adjustment, while the bypass regulating valves of the thermal power stations with bypass regulating valves remain closed, and the primary side inlet water regulating valves of each thermal power station are gradually closed by automatic control to reduce the flow of hot water entering the thermal power station, thereby ensuring that the heat absorption on the secondary side (cold water side) remains unchanged and that the heat used by users remains unchanged.

[0090] At this point, you can select some heating stations and open bypasses in those stations to allow some hot water to return to the return pipes of the heating network, thereby increasing the temperature of the return water tb in the heating network pipes. Since the amount of steam extracted from the external heating unit 1 increases, the temperature of the hot water in the heating network pipes increases, while the amount of heat used by users remains unchanged. The excess heat is stored in the pipes of the heating network, completing the heat storage process of the heating network.

[0091] Furthermore, the excellent insulation properties of energy-saving buildings can be utilized to unlock their heat storage capacity. Generally, not all thermal power stations are equipped with bypass systems, and there are also restrictions on the return water temperature of the pipes. When large amounts of heat need to be stored, bypass regulation alone cannot meet the required heat storage capacity. In this case, energy-saving buildings can be used for heat storage.

[0092] Specifically, when the amount of steam extracted from thermal power unit 1 for external heat supply increases, the primary outlet water temperature of the heating network's primary station 2 gradually rises. As the primary outlet water temperature rises, the primary inlet water temperature of each heating station increases accordingly, depending on its proximity to the primary station 2. At this point, maintaining or even increasing the primary inlet water control valves at the heating stations in each energy-saving building complex will increase the primary outlet water temperature, thereby increasing secondary heat absorption and the amount of heat entering the energy-saving building, completing the energy-saving building heat storage process.

[0093] Preferably, releasing the stored heat to provide heating to users comprises,

[0094] Determine the heat storage method of the thermal network;

[0095] If the heat storage method is to select some of the heating stations in the heat network for heat storage, the bypass of each heating station that has not stored heat is controlled to remain closed, the primary side water inlet valve of each heating station that has not stored heat is controlled to gradually increase, and the bypass of each heating station that has stored heat is controlled to reduce, so that the hot water stored in advance can enter the heat network for use by users;

[0096] If the heat storage method is to select the thermal network and energy-saving buildings to store heat together, then the thermal stations that store heat will be controlled to reduce the bypass so that the hot water stored in advance can enter the thermal network, and the primary side water inlet regulating valve of each energy-saving building will be controlled not to increase or even decrease.

[0097] It should be noted that when the thermal power unit 1 is operating at peak or deep regulation, a heat release process is carried out: that is, the amount of steam extracted by the thermal power unit 1 for external heat supply is reduced, and the primary side outlet water temperature of the heating network's first station 2 is gradually lowered. As the primary side outlet water temperature decreases, the primary side inlet water temperature of each thermal power station will gradually decrease according to the distance from the heating network's first station 2. At this time, the thermal power stations that do not store heat do not have a bypass or the bypass of the thermal power stations that do not store heat is closed, and the primary side inlet water regulating valve of the thermal power station is gradually opened using automatic control to increase the flow of hot water entering the thermal power station, thereby ensuring that the heat absorbed by the secondary side remains unchanged and that the heat used by users remains unchanged.

[0098] At this time, the heat storage thermal power station can reduce the bypass so that the hot water originally returned to the return pipe enters the thermal network for use by heating users, thereby reducing the return hot water temperature of the thermal network and realizing the reuse of the hot water stored in the thermal network pipes, completing the heat release process of the thermal network.

[0099] At the same time, if energy-saving building heat storage was previously used, reducing the amount of steam extracted from thermal power unit 1 for external heat supply will gradually reduce the primary outlet water temperature of the heating network's first station 2. As the primary outlet water temperature decreases, the primary inlet water temperature of each heating station will decrease individually, depending on its distance from the heating network's first station 2. At this point, the primary inlet water regulating valve of each energy-saving building will not be increased, or may even be decreased, resulting in a lower primary outlet water temperature for the energy-saving building. This, in turn, reduces heat absorption on the secondary side, reducing the amount of heat entering the energy-saving building and completing the energy-saving building's heat release process.

[0100] In addition to the above-mentioned control method for improving the peak-shaving capability of a thermal power plant, the present invention further provides a system for applying the control method for improving the peak-shaving capability of a thermal power plant disclosed in the above-mentioned embodiment, the system comprising:

[0101] Thermal power unit 1;

[0102] A heat pipe network connected to the thermal power unit 1;

[0103] The control device, connected to both the thermal power unit 1 and the heat pipe network, determines whether the thermal power unit 1 is operating at peak load or deep regulation. If not, it increases the steam extraction rate from the thermal power unit 1 for external heating and stores the heat corresponding to the excess steam. If so, it reduces the steam extraction rate from the thermal power unit 1 for external heating and releases the stored heat to provide heating to users. The structures of other components of the system are referenced in the prior art and will not be detailed here.

[0104] Preferably, the thermal network includes a thermal network head station 2, a thermal network circulation pump 3 and multiple thermal power stations; the thermal power unit 1 is connected to the input end of the thermal network head station 2, and the output end of the thermal network head station 2 is provided with a thermal network circulation pump 3. The thermal network circulation pump 3, the thermal power station and the other input end of the thermal network head station 2 are connected in sequence to form a loop, and the thermal network includes multiple parallel loops.

[0105] It should be noted that the multiple heating stations can be recorded as the first heating station Z1, the second heating station Z2, the pth heating station Zp..., and the nth heating station Zn. Among them, the heating stations made of energy-saving materials have energy-saving and heat preservation functions, that is, energy-saving buildings. In addition, some of the multiple heating stations have bypass valves, such as Figure 2 The second thermal power station Z2, the pth thermal power station Zp, and another part of the plurality of thermal power stations do not have a bypass regulating valve, for example Figure 2 The first thermal station Z1, the nth thermal station Zn. Figure 2 Take this as an example to illustrate.

[0106] Before the peak operation or deep adjustment operation of thermal power unit 1, the heat storage process is carried out: the demand for external heat extraction steam of thermal power unit 1 is increased L a , gradually increasing the outlet water temperature ta of the heating network first station 2. As the outlet water temperature ta of the heating network first station 2 increases, the primary side inlet water temperature t1 of each first thermal power station Z1 will increase one by one according to the distance from the heating network first station 2.

[0107] Since some thermal power stations do not have bypass regulating valves (such as the first thermal power station Z1 and the nth thermal power station Zn), they do not need to perform bypass adjustment. Some thermal power stations have bypass regulating valves (such as the second thermal power station Z2 and the pth thermal power station Zp), and their bypass regulating valves can be controlled to be closed. Moreover, the primary side water inlet regulating valve of each thermal power station is gradually closed using automatic control to reduce the flow of hot water entering the first thermal power station Z1, thereby ensuring that the heat absorption on the secondary side remains unchanged and the heat used by users remains unchanged.

[0108] At this time, part of the second thermal power station Z2 can be selected, and by opening the bypass regulating valve V3 of the second thermal power station Z2, part of the hot water can be returned to the return pipe, thereby increasing the primary network return water temperature t5 of the second thermal power station Z2.

[0109] Since the thermal power unit 1 supplies heat to the outside with steam extraction capacity L a The primary-side inlet water temperature t1 of the first heating station Z1 increases, while the user's heat consumption remains unchanged. The excess heat is stored in the pipes of the heating network, completing the heat storage process of the heating network. The above process is only used as an example for the first heating station Z1 and the second heating station Z2. The heat storage method of other heating stations is similar.

[0110] Furthermore, the excellent insulation properties of energy-saving buildings can be leveraged to unleash their heat storage capacity. Generally, not all thermal power stations are equipped with bypass systems, and there are also restrictions on the return water temperature of the pipes. When the required heat storage capacity is large and bypass regulation alone cannot meet the required heat storage capacity, energy-saving buildings can be used for heat storage. Assuming that the nth thermal power station Zn is an energy-saving building, we will use it as an example. The heat storage method for other energy-saving buildings is similar.

[0111] The external heat extraction steam volume L of thermal power unit 1 can be increased a As the outlet water temperature ta of the heating network's first station 2 increases, the primary network inlet water temperature t6 of each n-th heating station Zn (energy-saving building) will increase one by one according to its distance from the heating network's first station 2.

[0112] At this time, the primary side water inlet regulating valve V4 of each nth thermal power station Zn (energy-saving building) is not reduced, or even opened larger, so that the primary network return water temperature t7 of the nth thermal power station Zn (energy-saving building) is increased, thereby increasing the heat absorption on the secondary side, increasing the heat entering the energy-saving building, and completing the heat storage process of the nth thermal power station Zn (energy-saving building).

[0113] When the thermal power unit 1 is in peak operation or deep adjustment operation, the heat release process is carried out: the amount of steam extraction L supplied by the thermal power unit 1 to the outside can be reduced. a , gradually reducing the outlet water temperature ta of the heating network first station 2. As the outlet water temperature ta of the heating network first station 2 decreases, the primary side inlet water temperature t1 of each first thermal power station Z1 will decrease one by one according to the distance from the heating network first station 2.

[0114] At this time, each first thermal power station Z1 that has not stored heat has no bypass valve and does not need bypass control, or the bypass of each first thermal power station Z1 that has not stored heat is in a closed state. The primary side water inlet valve V1 of each first thermal power station Z1 is gradually opened by automatic control to increase the flow of hot water entering the first thermal power station Z1, thereby ensuring that the heat absorption on the secondary side remains unchanged and the heat used by the user remains unchanged.

[0115] At this point, the second heat storage station Z2 can lower its bypass valve V3, allowing the hot water originally returning to the return pipe to enter the heat network for consumption. This lowers the return water temperature t5 of the primary network at the second heat storage station Z2, allowing the hot water stored in the heat network pipes to be reused, completing the heat release process. The above process is illustrated using the first and second heat storage stations Z1 and Z2 as examples; other heat storage stations utilize the same heat release method.

[0116] At the same time, if energy-saving building heat storage is used, when the external heat extraction steam volume La of thermal power unit 1 is reduced, the outlet water temperature ta of the heating network's primary station 2 gradually decreases. As the outlet water temperature ta of the heating network's primary station 2 decreases, the primary network inlet water temperature t6 of each nth heating station Zn (energy-saving building) will decrease gradually based on its distance from the primary station 2.

[0117] At this point, the primary water inlet valve V4 of each nth thermal station Zn (energy-saving building) is not increased, or even decreased. This lowers the primary network return water temperature t7 of the nth thermal station Zn (energy-saving building), thereby reducing the heat absorbed by the secondary side and the amount of heat entering the nth thermal station Zn (energy-saving building), thus completing the heat release process of the nth thermal station Zn (energy-saving building). The above process is only illustrated by the nth thermal station Zn (energy-saving building); other energy-saving buildings have the same heat storage method.

[0118] It should be noted that the first thermal station Z1 and the second thermal station Z2 mentioned in this application document are only used to distinguish the difference in location and there is no order of precedence.

[0119] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other. Any combination of all the embodiments provided by the present invention is within the scope of protection of this invention and will not be described in detail here.

[0120] The above is a detailed introduction to the control method and system for improving the peak-shaving capacity of thermal power units provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified in several ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A control method for improving the peak-shaving capability of a thermal power unit, characterized in that: include: Determine whether the thermal power unit (1) is in peak operation or deep adjustment operation. If not, increase the extraction steam volume of the thermal power unit (1) for external heat supply and store the heat corresponding to the excess extraction steam volume, including: increasing the extraction steam volume of the thermal power unit (1) for external heat supply and gradually reducing the primary side water inlet regulating valve of each thermal power station in the thermal network; determine the maximum extraction steam volume L for external heat supply of the thermal power unit (1) b The electric power G of the thermal power unit (1) b The corresponding relationship is used to obtain the unit dispatch curve; according to the unit dispatch curve, the external heat extraction steam gap L of the thermal power unit (1) during peak operation or deep adjustment operation is determined. q According to the unit dispatch curve, before the thermal power unit (1) is in peak operation or deep adjustment operation, the external heat extraction steam gap L is stored in the thermal network q The heat corresponding to the steam; determine the heat storage capacity of the thermal network and the heat storage capacity of the energy-saving building according to the stored heat, and use the thermal network and energy-saving building to store heat; If so, the amount of steam extracted by the thermal power unit (1) for external heat supply is reduced, and the stored heat is released to provide heat to the user, including determining the heat storage method of the thermal network; If the heat storage method is to select some of the heating stations in the thermal network to store heat, the bypass of each heating station that has not stored heat is controlled to remain closed, the primary side water inlet regulating valve of each heating station that has not stored heat is controlled to gradually increase, and the heating stations that store heat are controlled to reduce the bypass, so that the hot water stored in advance enters the thermal network for use by users; if the heat storage method is to select the thermal network and energy-saving buildings to store heat together, the bypass of each heating station that stores heat is controlled to reduce, so that the hot water stored in advance enters the thermal network, and the primary side water inlet regulating valve of each energy-saving building is controlled not to increase or even to decrease.

2. The control method for improving the peak-shaving capability of a thermal power unit according to claim 1, characterized in that: The heat storage amount of the heat pipe network and the energy-saving building is determined based on the stored heat, and the heat storage amount of the heat pipe network and the energy-saving building is coordinated to store heat, including: Determine the shortage of steam extraction for external heating L q Is it less than the maximum storage capacity L of the thermal network? qDmax , if so, select some heating stations of the heating network for heat storage; If not, the heat pipe network and energy-saving building are selected to store heat together.

3. The control method for improving the peak load regulation capability of a thermal power unit according to claim 2, characterized in that: The step of selecting some heating stations in the heating network for heat storage includes: According to the maximum heat storage capacity of the bypass of each thermal power station, select from large to small to determine the thermal power station for heat storage; The bypass of the heat storage station is controlled to be opened wide, so that part of the hot water returns to the return pipe of the heat network to complete the heat storage process of the heat network.

4. The control method for improving the peak-shaving capability of a thermal power unit according to claim 3, characterized in that: The control determines that the bypass of the thermal power station with heat storage is opened wide, including: The bypass of the thermal power station with heat storage is controlled and determined to be opened gradually in the order of the near end, the middle end and the far end.

5. The control method for improving the peak load regulation capability of a thermal power unit according to claim 2, characterized in that: The selecting of the thermal network and the energy-saving building to jointly store heat includes: The maximum storage capacity L of the thermal network is stored qDmax The heat corresponding to the steam is stored in the energy-saving building to supply heat to the outside world. q With maximum storage capacity L qDmax The heat corresponding to the difference in steam.

6. The control method for improving the peak load regulation capability of a thermal power unit according to claim 5, characterized in that: The utilization of energy-saving buildings to store the steam shortage for external heating L q With maximum storage capacity L qDmax The heat corresponding to the difference in steam includes: Select all energy-saving buildings for heat storage, and on the basis of proportional distribution according to the maximum heat storage capacity of each energy-saving building, use the building insulation level coefficient k to correct the heat storage capacity of each energy-saving building; The primary side water inlet regulating valve of the thermal power station in each energy-saving building is controlled not to be reduced, or even opened wider, to complete the heat storage process of the energy-saving building.

7. A system, applied to the control method for improving the peak-shaving capability of a thermal power unit according to any one of claims 1 to 6, characterized in that: include: Thermal power unit (1); A heat pipe network connected to the heat generator unit (1), the heat pipe network comprising a heat network head station (2), a heat network circulation pump (3) and a plurality of heat stations; the heat generator unit (1) is connected to the input end of the heat network head station (2), the output end of the heat network head station (2) is provided with the heat network circulation pump (3), the heat network circulation pump (3), the heat station and the other input end of the heat network head station (2) are sequentially connected to form a loop, and the heat pipe network comprises a plurality of parallel loops; A control device is provided, wherein the thermal power unit (1) and the heat pipe network are both connected to the control device, and the control device is used to determine whether the thermal power unit (1) is in peak operation or deep adjustment operation. If not, the amount of steam extracted from the thermal power unit (1) for external heat supply is increased, and the heat corresponding to the excess steam is stored; if so, the amount of steam extracted from the thermal power unit (1) for external heat supply is reduced, and the stored heat is released to provide heat to users.

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