Energy storage black start power source system and method for power plants

Abstract

The application provides a power plant energy storage black start power source system and method, and belongs to the field of thermal power generation. The system comprises an energy storage black start power source body. The power output end of the energy storage black start power source body is connected to the power input end of a first auxiliary machine, a second auxiliary machine, a first auxiliary 6kV bus and a second auxiliary 6kV bus. The power output end of the first auxiliary 6kV bus is connected to the first auxiliary machine and a first energy storage system. The power output end of the second auxiliary 6kV bus is connected to the power input end of the second auxiliary machine and a second energy storage system. Compared with the traditional diesel generator or energy storage device directly connected to the 6kV auxiliary power bus for direct starting, the system can eliminate the excitation inrush current of large-capacity transformer auxiliary machines, reduce the impact current in the electrical starting process of fan and water pump auxiliary machines, greatly improve the safety and reliability of the black start process, effectively reduce the required energy storage capacity, reduce the initial investment cost and improve the overall economy.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of thermal power generation, and particularly relates to a power source system and method for black start of energy storage in a power plant. BACKGROUND

[0002] In a thermal power plant, a large number of auxiliary machines (such as fans, water pumps, etc.) are driven by three-phase asynchronous motors. When these motors are started by direct starting, the starting current can reach 47 times the rated current, causing a huge impact on the auxiliary power system.

[0003] If the energy storage system is directly connected to the auxiliary 6kV bus to start the auxiliary machines, in order to meet the requirement of short-time peak power during direct starting, the power level of the auxiliary energy storage converter and the capacity of the energy storage system must be increased. This directly leads to a serious over-provisioning of the energy storage system, and the capacity redundancy problem is prominent, which has a negative impact on the economy of the project.

[0004] The method of using auxiliary machines equipped with frequency converters or soft starters for variable frequency starting can effectively eliminate the impact current, but it also leads to an increase in system cost, an increase in active power loss, and a decrease in system efficiency. In addition, each auxiliary machine is equipped with a frequency converter, which makes maintenance extremely cumbersome and greatly increases the maintenance burden and labor cost of the power plant. SUMMARY

[0005] The present application provides a power source system and method for black start of energy storage in a power plant, which solves the problem of a huge impact on the auxiliary power system during starting of the auxiliary machines.

[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0007] In a first aspect, the present application provides a power source system for black start of energy storage in a power plant, comprising an energy storage black start power source body, a power input end of a first auxiliary machine, a second auxiliary machine, a first auxiliary 6kV bus and a second auxiliary 6kV bus is connected to a power output end of the energy storage black start power source body, a power output end of the first auxiliary 6kV bus is connected to the first auxiliary machine and a first energy storage system, and a power output end of the second auxiliary 6kV bus is connected to a power input end of the second auxiliary machine and a second energy storage system.

[0008] Preferably, the first auxiliary machine and the second auxiliary machine are of the same structure, wherein the first auxiliary machine comprises a first circuit breaker, a feed water pump type auxiliary machine, a feed water pump type auxiliary machine first circuit breaker, a feed water pump type auxiliary machine second circuit breaker, an induced draft fan type auxiliary machine, an induced draft fan type auxiliary machine first circuit breaker, an induced draft fan type auxiliary machine second circuit breaker, a steam turbine transformer, a steam turbine transformer first circuit breaker and a steam turbine transformer second circuit breaker, wherein:

[0009] The first 6kV bus is connected with the low-voltage side of the first circuit breaker and the starting standby transformer, and is connected with the water pump auxiliary machine through the first circuit breaker of the water pump auxiliary machine; the first 6kV bus is connected with the induced draft fan auxiliary machine through the first circuit breaker of the induced draft fan auxiliary machine; the first 6kV bus is connected with the steam turbine transformer through the first circuit breaker of the steam turbine transformer.

[0010] The power output end of the energy storage black start power source body is connected with the water pump auxiliary machine, the induced draft fan auxiliary machine and the steam turbine transformer through the second circuit breaker of the water pump auxiliary machine, the second circuit breaker of the induced draft fan auxiliary machine and the second circuit breaker of the steam turbine transformer respectively.

[0011] Preferably, the first energy storage system and the second energy storage system are the same structure, wherein the first energy storage system comprises a first energy storage device, a first energy storage converter, a first energy storage transformer and a first energy storage circuit breaker, wherein:

[0012] The output end of the first energy storage device is connected with the first 6kV bus through the first energy storage converter, the first energy storage transformer and the first energy storage circuit breaker in sequence.

[0013] Preferably, the energy storage black start power source body comprises a black start energy storage device, a black start energy storage converter, a black start energy storage transformer, a black start energy storage circuit breaker, a black start energy storage system 35kV bus, a black start 6kV bus, a black start transformer first circuit breaker, a black start transformer second circuit breaker, a black start transformer, an energy storage transformer circuit breaker and an energy storage transformer, wherein:

[0014] The output end of the black start energy storage device is connected with the black start energy storage system 35kV bus through the black start energy storage converter, the black start energy storage transformer and the black start energy storage circuit breaker in sequence;

[0015] The black start energy storage system 35kV bus is connected with the black start 6kV bus through the black start transformer second circuit breaker, the black start transformer, the black start transformer first circuit breaker in sequence;

[0016] The black start 6kV bus is connected with the water pump auxiliary machine, the induced draft fan auxiliary machine and the steam turbine transformer through the second circuit breaker of the water pump auxiliary machine, the second circuit breaker of the induced draft fan auxiliary machine and the second circuit breaker of the steam turbine transformer respectively;

[0017] The black start energy storage system 35kV bus is connected with the first 6kV bus through the energy storage transformer circuit breaker and the energy storage transformer in sequence.

[0018] Preferably, the black start 6kV bus is further provided with a black start 6kV bus voltage transformer; the first auxiliary 6kV bus is further connected with a first auxiliary 6kV bus voltage transformer; the black start energy storage system 35kV bus is further connected with a black start energy storage system 35kV bus voltage transformer;

[0019] The output terminals of the first auxiliary 6kV bus voltage transformer and the black start 6kV bus voltage transformer are connected with the input terminals of the auxiliary quasi-synchronization device, and the output terminals of the auxiliary quasi-synchronization device are respectively connected with the first circuit breaker of the water pump auxiliary, the first circuit breaker of the induced draft fan auxiliary and the first circuit breaker of the steam turbine transformer.

[0020] The output terminals of the first auxiliary 6kV bus voltage transformer and the black start energy storage system 35kV bus voltage transformer are connected with the black start power source system quasi-synchronization device, and the output terminals of the black start power source system quasi-synchronization device are connected with the first circuit breaker of the black start transformer, the second circuit breaker of the black start transformer and the circuit breaker of the energy storage transformer.

[0021] In the second aspect, the power plant energy storage black start power source method provided by the present application comprises the following steps:

[0022] Based on the single-sided start principle, the first auxiliary of the power plant is started by using the energy storage black start power source body and the first energy storage system, or the second auxiliary of the power plant is started by using the energy storage black start power source body and the second energy storage system.

[0023] During the start, first, the energy storage system is used to supply power to the auxiliary 6KV bus in a zero-voltage step-up manner until the rated voltage is reached; then the energy storage black start power source body is used to start the first auxiliary of the power plant or the second auxiliary of the power plant in a zero-voltage step-up manner combined with a frequency conversion start manner, and after the first auxiliary of the power plant or the second auxiliary of the power plant is successfully started, the power supply of the first auxiliary of the power plant or the second auxiliary of the power plant is switched to the auxiliary 6KV bus.

[0024] After the power supply switching is completed, the energy storage black start power source body is integrated into the auxiliary 6KV bus and the energy storage system participates in frequency modulation and peak regulation.

[0025] Preferably, the energy storage system is used to supply power to the auxiliary 6KV bus in a zero-voltage step-up manner until the rated voltage is reached, and the specific method is as follows:

[0026] The energy storage circuit breaker and the first circuit breaker are closed, the energy storage system is gradually boosted to the rated voltage in a zero-voltage step-up manner, so that the energy storage transformer, the start standby transformer and the first auxiliary 6kV bus are powered.

[0027] Preferably, the energy storage black start power source body is used to start the first auxiliary of the power plant in a zero-voltage step-up manner combined with a frequency conversion start manner, and the specific method is as follows:

[0028] Close the black start energy storage circuit breaker, the black start transformer second circuit breaker, the black start transformer first circuit breaker and the steam turbine transformer second circuit breaker;

[0029] The energy storage black start power source body supplies power to the steam turbine transformer in a zero-voltage-rising manner until the rated voltage is reached; then, the voltage of the plant 6kV bus and the black start 6kV bus is detected in real time, and if the frequency, amplitude and phase of the voltage of the plant 6kV bus and the black start 6kV bus are the same, the steam turbine transformer first circuit breaker is closed, and the output power of the energy storage black start power source body is gradually reduced until it is zero, while the output power of the energy storage device is gradually increased until the energy storage black start power source system is stably running, and the steam turbine transformer second circuit breaker is cut off.

[0030] The induced draft fan auxiliary machine second circuit breaker is closed, the energy storage black start power source body starts the induced draft fan auxiliary machine in a variable frequency starting manner until the rated voltage is reached; then, the voltage of the plant 6kV bus and the black start 6kV bus is detected in real time, and if the frequency, amplitude and phase of the voltage of the plant 6kV bus and the black start 6kV bus are the same, the induced draft fan auxiliary machine first circuit breaker is closed, and the output power of the energy storage black start power source body is gradually reduced until it is zero, while the output power of the energy storage device is gradually increased until the energy storage black start power source system is stably running, and the induced draft fan auxiliary machine second circuit breaker is cut off.

[0031] The feed water pump auxiliary machine second circuit breaker is closed, the energy storage black start power source body starts the feed water pump auxiliary machine in a variable frequency starting manner until the rated voltage is reached; then, the voltage of the plant 6kV bus and the black start 6kV bus is detected in real time, and if the frequency, amplitude and phase of the voltage of the plant 6kV bus and the black start 6kV bus are the same, the feed water pump auxiliary machine first circuit breaker is closed, and the output power of the energy storage black start power source body is gradually reduced until it is zero, while the output power of the energy storage device is gradually increased until the energy storage black start power source system is stably running, and the feed water pump auxiliary machine second circuit breaker is cut off.

[0032] Preferably, the energy storage black start power source body supplies power to the steam turbine transformer in a zero-voltage-rising manner until the rated voltage is reached, wherein the control mode of the black start energy storage converter in the energy storage black start power source body is voltage control outer ring combined with current control inner ring, and the specific method is as follows:

[0033] The voltage reference value at the current time is obtained;

[0034] The voltage control outer ring takes the deviation between the voltage reference value at the current time and the actual voltage as the input, and outputs the reference value of the current inner ring through dynamic self-adaptive PI adjustment;

[0035] The current control inner loop takes the deviation between the reference current output by the voltage control outer loop and the actual current as input, and outputs a SPWM modulation wave input signal of the energy storage converter.

[0036] Preferably, after the power supply switching is completed, the energy storage black start power source body is integrated into the plant 6KV bus and the energy storage system participates in frequency modulation and peak regulation, and the specific method is:

[0037] The voltage of the plant 6kV bus and the black start 6kV bus is detected in real time, if the frequency, amplitude and phase of the voltage of the plant 6kV bus and the black start energy storage system 35kV bus in the energy storage black start power source body are the same, the first circuit breaker of the black start transformer and the second circuit breaker of the black start transformer are cut off, and the energy storage transformer circuit breaker is closed, thereby completing the integration of the energy storage black start power source body into the plant 6KV bus and the energy storage system participating in frequency modulation and peak regulation.

[0038] Compared with the prior art, the energy storage black start power source system for power plant provided by the present application has the following beneficial effects:

[0039] Compared with the traditional diesel generator or energy storage device directly connected to the 6kV plant bus for direct start, the energy storage black start power source system for power plant provided by the present application can eliminate the excitation inrush current of large-capacity transformer auxiliary machines, reduce the impact current in the electrical starting process of fan and water pump auxiliary machines, greatly improve the safety and reliability of the black start process, effectively reduce the required energy storage capacity, reduce the initial investment cost, and improve the overall economy.

[0040] Further, each auxiliary machine is equipped with two starting power sources, and the black start / normal operation power supply switching can be realized by one set of quasi-synchronization device, thereby improving the reliability of the system.

[0041] Further, the energy storage black start power source body can participate in frequency modulation, peak regulation and other auxiliary services in combination with other plant energy storage systems in the normal operation condition, thereby greatly improving the utilization rate of the energy storage system.

[0042] In summary, the energy storage black start power source system for power plant has good economy and high reliability, is suitable for various common auxiliary machine black start scenes, and has wide application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 The first plant bus and auxiliary machine are taken as an example for the principle structure diagram of the embodiment of the present application;

[0044] Figure 2 The zero voltage rise control logic diagram is related to the embodiment of the present application;

[0045] Figure 3 The control logic diagram of the energy storage black start power source body is related to the embodiment of the present application;

[0046] The components include: 1. Start-up standby transformer; 2. First auxiliary plant equipment; 3. First energy storage system; 4. Energy storage black start-up power source; 21. First 6kV busbar for plant use; 22. First circuit breaker; 23. Auxiliary water pumps; 24. First circuit breaker for auxiliary water pumps; 25. Second circuit breaker for auxiliary water pumps; 26. Auxiliary induced draft fans; 27. First circuit breaker for auxiliary induced draft fans; 28. Second circuit breaker for auxiliary induced draft fans; 29. ​​Steam turbine transformer; 210. First circuit breaker for steam turbine transformer; 211. Second circuit breaker for steam turbine transformer; 31. First energy storage equipment; 32. First energy storage converter; 33. First energy storage transformer; 34. First energy storage circuit breaker. Devices; 41. Black start energy storage equipment; 42. Black start energy storage converter; 43. Black start energy storage transformer; 44. Black start energy storage circuit breaker; 45. 35kV busbar of black start energy storage system; 46. 6kV busbar of black start; 47. First circuit breaker of black start transformer; 48. Second circuit breaker of black start transformer; 49. Black start transformer; 410. Energy storage transformer circuit breaker; 411. Energy storage transformer; 51. 6kV busbar voltage transformer for first plant use; 52. 6kV busbar voltage transformer for black start; 53. 35kV busbar voltage transformer for black start energy storage system; 61. Auxiliary machine quasi-synchronizing device; 62. Quasi-synchronizing device for black start power source system. Detailed Implementation

[0047] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0048] Example 1

[0049] like Figure 1 As shown, the power plant energy storage black start power source system provided in this embodiment includes a starting backup transformer 1, a first auxiliary plant unit 2, a first energy storage system 3, a second auxiliary plant unit, a second energy storage system, and an energy storage black start power source body 4. The first auxiliary plant unit 2 and the second auxiliary plant unit have the same structure. The first auxiliary plant unit 2 will be used as an example for explanation. Specifically:

[0050] The high-voltage side inlet of the standby transformer 1 is connected to the main wiring of the external thermal power plant, and the low-voltage side outlet of the standby transformer 1 is connected to the first plant auxiliary machine 2 and the first energy storage system 3.

[0051] The first auxiliary machine 2 is connected to the energy storage black start power source body 4.

[0052] The first auxiliary machine 2 includes a first auxiliary 6kV bus 21, a first circuit breaker 22, a feed pump auxiliary machine 23, a feed pump auxiliary machine first circuit breaker 24, a feed pump auxiliary machine second circuit breaker 25, an induced draft fan auxiliary machine 26, an induced draft fan auxiliary machine first circuit breaker 27, an induced draft fan auxiliary machine second circuit breaker 28, a steam turbine transformer 29, a steam turbine transformer first circuit breaker 210, and a steam turbine transformer second circuit breaker 211, wherein:

[0053] The first auxiliary 6kV bus 21 is connected to the low-voltage side of the starting standby transformer 1 through the first circuit breaker 22, and is connected to the feed pump auxiliary machine 23 through the feed pump auxiliary machine first circuit breaker 24; the first auxiliary 6kV bus 21 is connected to the induced draft fan auxiliary machine 26 through the induced draft fan auxiliary machine first circuit breaker 27; and the first auxiliary 6kV bus 21 is connected to the steam turbine transformer 29 through the steam turbine transformer first circuit breaker 210.

[0054] The energy storage black start power source body 4 includes a black start energy storage device 41, a black start energy storage converter 42, a black start energy storage transformer 43, a black start energy storage circuit breaker 44, a black start energy storage system 35kV bus 45, a black start 6kV bus 46, a black start transformer first circuit breaker 47, a black start transformer second circuit breaker 48, a black start transformer 49, an energy storage transformer circuit breaker 410, and an energy storage transformer 411, wherein:

[0055] The output end of the black start energy storage device 41 is connected in sequence through the black start energy storage converter 42, the black start energy storage transformer 43, the black start energy storage circuit breaker 44, and the black start energy storage system 35kV bus 45.

[0056] The black start energy storage system 35kV bus 45 is connected in sequence through the black start transformer second circuit breaker 48, the black start transformer 49, the black start transformer first circuit breaker 47, and the black start 6kV bus 46.

[0057] The black start 6kV bus 46 is connected to the feed pump auxiliary machine 23, the induced draft fan auxiliary machine 26, and the steam turbine transformer 29 through the feed pump auxiliary machine second circuit breaker 25, the induced draft fan auxiliary machine second circuit breaker 28, and the steam turbine transformer second circuit breaker 211, respectively.

[0058] The black start energy storage system 35kV bus 45 is connected to the first auxiliary 6kV bus 21 in sequence through the energy storage transformer circuit breaker 410 and the energy storage transformer 411.

[0059] The black start 6kV bus 46 is further provided with a black start 6kV bus voltage transformer 52.

[0060] The first auxiliary 6kV bus 21 is also connected with a first auxiliary 6kV bus voltage transformer 51.

[0061] The black start energy storage system 35kV bus 45 is also connected with a black start energy storage system 35kV bus voltage transformer 53.

[0062] The first energy storage system 3 comprises a first energy storage device 31, a first energy storage converter 32, a first energy storage transformer 33 and a first energy storage circuit breaker 34, wherein:

[0063] The output of the first energy storage device 31 is connected with the first auxiliary 6kV bus 21 through the first energy storage converter 32, the first energy storage transformer 33 and the first energy storage circuit breaker 34 in sequence.

[0064] The outputs of the first auxiliary 6kV bus voltage transformer 51 and the black start 6kV bus voltage transformer 52 are connected with the input of an auxiliary quasi-synchronization device 61, and the output of the auxiliary quasi-synchronization device 61 is connected with the first circuit breaker 24 of the water pump auxiliary, the first circuit breaker 27 of the induced draft fan auxiliary and the first circuit breaker 210 of the turbine transformer.

[0065] The outputs of the first auxiliary 6kV bus voltage transformer 51 and the black start energy storage system 35kV bus voltage transformer 53 are connected with the black start power source system quasi-synchronization device 62, and the output of the black start power source system quasi-synchronization device 62 is connected with the first circuit breaker 47 of the black start transformer, the second circuit breaker 48 of the black start transformer and the circuit breaker 410 of the energy storage transformer.

[0066] Embodiment 2

[0067] The power plant energy storage black start power source method provided in the embodiment comprises the following steps:

[0068] Based on the single-sided starting principle, the first auxiliary of the power plant is started by using the energy storage black start power source body and the first energy storage system, or the second auxiliary of the power plant is started by using the energy storage black start power source body and the second energy storage system.

[0069] During the starting, the energy storage system is first used to supply power to the auxiliary 6KV bus in a zero-voltage step-up manner until the rated voltage is reached; then the energy storage black start power source body is used to start the first auxiliary of the power plant or the second auxiliary of the power plant in a zero-voltage step-up manner combined with a frequency conversion starting manner, and after the first auxiliary of the power plant or the second auxiliary of the power plant is successfully started, the power supply of the first auxiliary of the power plant or the second auxiliary of the power plant is switched to the auxiliary 6KV bus.

[0070] After the power supply switching is completed, the energy storage black start power source body is integrated into the auxiliary 6KV bus and the energy storage system to participate in frequency modulation and peak regulation.

[0071] Embodiment 3

[0072] As Figure 3 shown, the power plant energy storage black start power source method provided by the embodiment, the system state before black start: unit full stop state, boiler extinguishing, power failure, booster station busbar power failure, unit in hot or extremely hot state; the control method of the energy storage black start power source system includes the following steps:

[0073] Step 1, the first auxiliary machine 6kV bus receives power: the first energy storage circuit breaker 34 and the first circuit breaker 22 are closed, the first energy storage system 3 is gradually boosted to the rated voltage in the zero start-up mode, so that the first energy storage transformer 33, the standby transformer 1, and the first auxiliary machine 6kV bus 21 receive power. This method ensures that the transformer receives power without generating excitation inrush current.

[0074] Step 2, the first auxiliary machine receives power, wherein:

[0075] The black start energy storage circuit breaker 44, the black start transformer second circuit breaker 48, the black start transformer first circuit breaker 47, and the turbine transformer second circuit breaker 211 are closed. The energy storage black start power source body 4 is gradually boosted to the rated voltage in the zero start-up mode, ensuring that the turbine transformer 29 receives power without generating excitation inrush current.

[0076] The auxiliary machine quasi-synchronization device 61 detects the frequency, amplitude, and phase of the voltage in the first auxiliary machine 6kV bus voltage transformer 51 and the black start 6kV bus voltage transformer 52. The turbine transformer first circuit breaker 210 is closed when the voltage frequency, amplitude, and phase are the same. Then gradually reduce the output power of the energy storage black start power source body to 0, while gradually increasing the output power of the first energy storage system 3. When the operation of the energy storage black start power source system reaches balance and stability (i.e., the voltage amplitude and frequency of the system remain within the normal operating range and are stable, and the active power and reactive power supply and demand reach balance), the turbine transformer second circuit breaker 211 is disconnected, and the turbine transformer 29 is smoothly switched to the first auxiliary machine 6kV bus 21.

[0077] The current state of the energy storage black start power source body 4 is maintained, and the next start-up process is waited for.

[0078] The second circuit breaker 28 of the induced draft fan auxiliary machine is closed, and the energy storage black start power source body 4 starts the induced draft fan auxiliary machine 26 in the variable frequency start-up mode until the motor speed reaches the rated speed and the electrical voltage reaches the rated voltage.

[0079] The auxiliary synchronizing device 61 detects the frequency, amplitude, and phase of the voltage in the first 6kV bus voltage transformer 51 and the black start 6kV bus voltage transformer 52, and checks the synchronization closing of the first circuit breaker 27 of the induced draft fan auxiliary machine. Then, it gradually reduces the output power of the energy storage black start power source 4 to 0, while gradually increasing the output power of the first energy storage system 3. When the operation of the energy storage black start power source system reaches a balanced and stable state, it disconnects the second circuit breaker 28 of the induced draft fan auxiliary machine and smoothly switches the induced draft fan auxiliary machine 26 to the first 6kV bus 21 of the plant.

[0080] Maintain the current state of the energy storage black start power source body 4 and wait for the next start-up process;

[0081] The second circuit breaker 25 of the water pump auxiliary machine is closed, and the energy storage black start power source body 4 adopts the frequency conversion start method to start the water pump auxiliary machine 23 until the motor speed reaches the rated speed and the electrical voltage reaches the rated.

[0082] The auxiliary synchronizing device 61 detects the frequency, amplitude, and phase of the voltage in the first 6kV bus voltage transformer 51 and the black start 6kV bus voltage transformer 52, and checks the synchronization and closing of the first circuit breaker 24 of the feedwater pump auxiliary machine. Then, it gradually reduces the output power of the energy storage black start power source 4 to 0, while gradually increasing the output power of the first energy storage system 3. When the operation of the energy storage black start power source system reaches a balanced and stable state, it disconnects the second circuit breaker 25 of the feedwater pump auxiliary machine and smoothly switches the feedwater pump auxiliary machine 23 to the first 6kV bus 21.

[0083] Step 3: The black start power source system completes the start-up of all auxiliary loads. The black start power source system quasi-synchronization device 62 detects the frequency, amplitude and phase of the voltage in the first 6kV bus voltage transformer 51 and the black start energy storage system 35kV bus voltage transformer 53. It checks and closes the energy storage transformer circuit breaker 410, and disconnects the first circuit breaker 47 and the second circuit breaker 48 of the black start transformer. At this time, the energy storage black start power source body 4 is integrated into the first 6kV bus 21 and the first energy storage system 3 as a conventional energy storage system to participate in frequency regulation, peak shaving and other auxiliary services.

[0084] Example 4

[0085] like Figure 2 As shown, based on Example 2, the power plant black-start power source method for energy storage provided in this example gradually increases the voltage to the rated voltage using a zero-start boost method. The black-start energy storage converter in the power source 4 employs a voltage control outer loop + current control inner loop structure. Unlike other similar technologies, this example introduces dynamic adaptive PI parameter adjustment. The PI parameter is dynamically adjusted according to the load current change rate. The specific method is as follows:

[0086] The current time voltage reference value is obtained by using the following formula :

[0087]

[0088] In the formula, is the current time voltage reference value; is the initial voltage; is the time for quickly establishing the initial voltage; is the time for completing the voltage rise; is the rated voltage. The 0~T1 segment is a fast voltage building segment, avoiding the residual magnetic region of the transformer; the T1~T2 segment is a voltage rise segment, reducing the voltage rise speed when the current change rate is large, and suppressing the field current inrush; the transformer is maintained at the rated voltage after T2 , and the voltage rise process is completed; is the exponential; is the current time; is the value of the load current change rate (unit: kA / s).

[0089] The voltage control outer ring takes the deviation between the current time voltage reference value and the actual voltage as the input, and outputs the reference value of the current inner ring through dynamic adaptive PI adjustment , and the specific formula is: ;

[0090] In the formula, is the current time actual voltage; is the proportional coefficient; is the integral coefficient; is the integral term of the PI regulator, which is the integral operation of the dynamic integral coefficient .

[0091] The current control inner ring takes the deviation between the reference current output by the voltage control outer ring and the actual current as the input, and outputs the SPWM modulation wave input signal of the black start energy storage converter :

[0092] In the formula, is the current time actual current; is the proportional coefficient; is the integral coefficient; is the SPWM modulation wave voltage reference value of the energy storage converter.

[0093] The dynamic adaptive PI parameter expression: when the load current change rate is large, the proportional action is enhanced to realize fast response, and the integral action is suppressed to avoid overshoot:

[0094] The proportional coefficient ;

[0095] Integral coefficient ;

[0096] wherein, , , and are fixed parameters, ensuring the basic stability and dynamic performance of the system in typical operating conditions, and the fixed parameters are obtained by off-line setting; , , , , , , , are adaptive coefficients, which are dynamically adjusted based on factors such as the actual load current rate of change.

[0097] The specific method of frequency conversion starting is:

[0098] The starting process always maintains constant magnetic flux, that is, the ratio of voltage to frequency is always a constant, and the voltage and the frequency increase proportionally.

[0099] The above-described embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements for some technical features therein; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A black start power source system for power plants, characterized by, The power output end of the energy storage black start power source body is connected with the power input end of the first auxiliary machine, the second auxiliary machine, the first auxiliary 6kV bus and the second auxiliary 6kV bus respectively, the power output end of the first auxiliary 6kV bus is connected with the first auxiliary machine and the first energy storage system, and the power output end of the second auxiliary 6kV bus is connected with the power input end of the second auxiliary machine and the second energy storage system. The first auxiliary machine and the second auxiliary machine are of the same structure, wherein the first auxiliary machine comprises a first circuit breaker, a feed water pump auxiliary machine, a feed water pump auxiliary machine first circuit breaker, a feed water pump auxiliary machine second circuit breaker, an induced draft fan auxiliary machine, an induced draft fan auxiliary machine first circuit breaker, an induced draft fan auxiliary machine second circuit breaker, a steam turbine transformer, a steam turbine transformer first circuit breaker and a steam turbine transformer second circuit breaker, wherein: The first auxiliary 6kV bus is connected with the first circuit breaker and the low voltage side of the starting standby transformer, the first auxiliary 6kV bus is connected with the feed water pump auxiliary machine through the feed water pump auxiliary machine first circuit breaker, the first auxiliary 6kV bus is connected with the induced draft fan auxiliary machine through the induced draft fan auxiliary machine first circuit breaker, and the first auxiliary 6kV bus is connected with the steam turbine transformer through the steam turbine transformer first circuit breaker. The power output end of the energy storage black start power source body is connected with the feed water pump auxiliary machine, the induced draft fan auxiliary machine and the steam turbine transformer through the feed water pump auxiliary machine second circuit breaker, the induced draft fan auxiliary machine second circuit breaker and the steam turbine transformer second circuit breaker respectively.

2. The energy storage black start power source system for power plants of claim 1, wherein, The first energy storage system and the second energy storage system are of the same structure, wherein the first energy storage system comprises a first energy storage device, a first energy storage converter, a first energy storage transformer and a first energy storage circuit breaker, wherein: The output end of the first energy storage device is connected with the first auxiliary 6kV bus through the first energy storage converter, the first energy storage transformer and the first energy storage circuit breaker in sequence.

3. The energy storage black start power source system for power plants of claim 1, wherein, The energy storage black start power source body comprises a black start energy storage device, a black start energy storage converter, a black start energy storage transformer, a black start energy storage circuit breaker, a black start energy storage system 35kV bus, a black start 6kV bus, a black start transformer first circuit breaker, a black start transformer second circuit breaker, a black start transformer, an energy storage transformer circuit breaker and an energy storage transformer, wherein: The output end of the black start energy storage device is connected with the black start energy storage system 35kV bus through the black start energy storage converter, the black start energy storage transformer and the black start energy storage circuit breaker in sequence; The black start energy storage system 35kV bus is connected with the black start 6kV bus through the black start transformer second circuit breaker, the black start transformer, the black start transformer first circuit breaker in sequence; The black start 6kV bus is connected with the feed water pump auxiliary machine, the induced draft fan auxiliary machine and the steam turbine transformer through the feed water pump auxiliary machine second circuit breaker, the induced draft fan auxiliary machine second circuit breaker and the steam turbine transformer second circuit breaker respectively; The black start energy storage system 35kV bus is connected with the first auxiliary 6kV bus through the energy storage transformer circuit breaker and the energy storage transformer in sequence.

4. The energy storage black start power source system for power plants of claim 3, wherein, The black start 6kV bus is also provided with a black start 6kV bus voltage transformer; the first auxiliary 6kV bus is also connected with a first auxiliary 6kV bus voltage transformer; the black start energy storage system 35kV bus is also connected with a black start energy storage system 35kV bus voltage transformer; The output ends of the first auxiliary 6kV bus voltage transformer and the black start 6kV bus voltage transformer are connected with the input end of an auxiliary quasi-synchronization device, and the output end of the auxiliary quasi-synchronization device is connected with a first circuit breaker of a water pump auxiliary machine, a first circuit breaker of a draft fan auxiliary machine and a first circuit breaker of a steam turbine transformer; The output ends of the first auxiliary 6kV bus voltage transformer and the black start energy storage system 35kV bus voltage transformer are connected with a black start power source system quasi-synchronization device, and the output end of the black start power source system quasi-synchronization device is connected with a first circuit breaker of a black start transformer, a second circuit breaker of the black start transformer and a circuit breaker of an energy storage transformer.

5. A method of black start power source for power plants based on the black start power source for power plants system according to any of claims 1-4, characterized in that, The method comprises the following steps: Based on the single-sided starting principle, the first auxiliary machine is started by using the energy storage black start power source body and the first energy storage system, or the second auxiliary machine is started by using the energy storage black start power source body and the second energy storage system; During the starting, the energy storage system is first used to supply power to the auxiliary 6KV bus in a zero-voltage-rising manner until the rated voltage is reached; then the energy storage black start power source body is used to start the first auxiliary machine or the second auxiliary machine in a zero-voltage-rising manner combined with a frequency conversion starting manner, and after the first auxiliary machine or the second auxiliary machine is successfully started, the power supply of the first auxiliary machine or the second auxiliary machine is switched to the auxiliary 6KV bus; After the power supply switching is completed, the energy storage black start power source body is integrated into the auxiliary 6KV bus and participates in frequency modulation and peak regulation together with the energy storage system.

6. The method of claim 5, wherein the method further comprises: The energy storage system is used to supply power to the auxiliary 6KV bus in a zero-voltage-rising manner until the rated voltage is reached, and the specific method is as follows: The energy storage circuit breaker and the first circuit breaker are closed, the energy storage system is gradually raised to the rated voltage in a zero-voltage-rising manner, so that the energy storage transformer, the starting standby transformer and the first auxiliary 6kV bus are powered.

7. The method of claim 5, wherein the method further comprises: The energy storage black start power source body is used to start the first auxiliary machine in a zero-voltage-rising manner combined with a frequency conversion starting manner, and the specific method is as follows: The black start energy storage circuit breaker, the black start transformer second circuit breaker, the black start transformer first circuit breaker and the steam turbine transformer second circuit breaker are closed; The energy storage black start power source body is used to supply power to the steam turbine transformer in a zero-voltage-rising manner until the rated voltage is reached; then the voltage of the auxiliary 6kV bus and the black start 6kV bus is detected in real time, if the frequency, amplitude and phase of the voltage of the auxiliary 6kV bus and the black start 6kV bus are the same, the steam turbine transformer first circuit breaker is closed, the output power of the energy storage black start power source body is gradually reduced to zero, and the output power of the energy storage device is gradually increased until the energy storage black start power source system is stably operated, and the steam turbine transformer second circuit breaker is cut off. The second circuit breaker of the induced draft fan auxiliary machine is closed, and the energy storage black start power source body starts the induced draft fan auxiliary machine in a variable frequency starting mode until the rated voltage is reached; thereafter, the voltage of the plant 6kV bus and the black start 6kV bus is detected in real time, and if the frequency, amplitude and phase of the voltage of the plant 6kV bus and the black start 6kV bus are the same, the first circuit breaker of the induced draft fan auxiliary machine is closed, and the output power of the energy storage black start power source body is gradually reduced until it is zero, while the output power of the energy storage device is gradually increased until the energy storage black start power source system is stably operated, and the second circuit breaker of the induced draft fan auxiliary machine is cut off. The second circuit breaker of the induced draft fan auxiliary machine is closed, and the energy storage black start power source body starts the induced draft fan auxiliary machine in a variable frequency starting mode until the rated voltage is reached; thereafter, the voltage of the plant 6kV bus and the black start 6kV bus is detected in real time, and if the frequency, amplitude and phase of the voltage of the plant 6kV bus and the black start 6kV bus are the same, the first circuit breaker of the induced draft fan auxiliary machine is closed, and the output power of the energy storage black start power source body is gradually reduced until it is zero, while the output power of the energy storage device is gradually increased until the energy storage black start power source system is stably operated, and the second circuit breaker of the induced draft fan auxiliary machine is cut off.

8. The method of claim 7, wherein the method further comprises: The energy storage black start power source body supplies power to the turbine transformer in a zero-voltage boosting mode until the rated voltage, wherein the control mode of the black start energy storage converter in the energy storage black start power source body is voltage control outer ring combined with current control inner ring, and the specific method is as follows: The voltage reference value at the current time is obtained; The voltage control outer ring takes the deviation between the voltage reference value at the current time and the actual voltage as the input, and outputs the reference value of the current inner ring through dynamic self-adaptive PI regulation; The current control inner ring takes the deviation between the reference current output by the voltage control outer ring and the actual current as the input, and outputs the SPWM modulation wave input signal of the energy storage converter.

9. The method of claim 5, wherein the method further comprises: After the power supply switching is completed, the energy storage black start power source body is connected to the plant 6kV bus and the energy storage system for frequency modulation and peak regulation, and the specific method is as follows: The voltage of the plant 6kV bus and the black start 6kV bus is detected in real time, and if the frequency, amplitude and phase of the voltage of the plant 6kV bus and the black start 6kV bus are the same, the first circuit breaker of the black start transformer and the second circuit breaker of the black start transformer are cut off, the energy storage transformer circuit breaker is closed, and the energy storage black start power source body is connected to the plant 6kV bus and the energy storage system for frequency modulation and peak regulation.

Images