Black start method and device for power plant based on energy storage system and coordination controller

Abstract

The application provides a black start method and device of a power plant based on an energy storage system and a coordination controller. The energy storage system comprises a plurality of parallel energy storage converters. The method comprises: controlling all energy storage converters in the energy storage system to shut down and controlling all energy storage converters in the energy storage system to switch to an off-grid VSG state; controlling a first energy storage converter to start in a voltage slow start mode; the first energy storage converter is any one of the energy storage converters in the energy storage system; after the first energy storage converter is started, controlling each energy storage converter in the energy storage system except the first energy storage converter to start in turn; wherein the energy storage converters in the energy storage system supply power to the motors of the power plant during the starting process and after the starting process is completed, so that the motors drive the power generation equipment to start and restore the power grid supply. The application does not instantaneously input a large voltage, so it does not bring a large impact current to the system, and can improve the stability and reliability of the power plant system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of black start, and in particular to a power plant black start method based on an energy storage system, a device and a coordination controller. BACKGROUND

[0002] Black start refers to the following process: when a power grid stops power supply due to some faults, a power plant is disconnected from an external power grid and all power generation equipment in the power plant is stopped, a local power source in the power plant is used to supply power to the equipment in the power plant, and the power generation equipment is driven to operate, so as to realize self-start of the power generation equipment and restore power supply of the power grid. The black start can greatly improve the fault recovery capability of the power grid.

[0003] At present, the black start of the power plant is usually performed in the following manner: a local power source is used to build off-grid voltage, and then a large voltage is instantaneously put into the system. However, the power plant usually has a transformer with a capacity of hundreds of megawatts. In the case of a large capacity, the large voltage is instantaneously put into the system, which can easily cause a large impact current and affect the stability and reliability of the power plant system. SUMMARY

[0004] Embodiments of the present application provide a power plant black start method based on an energy storage system, a device and a coordination controller, to solve the problem that the existing black start method instantaneously puts in a large voltage, which can easily cause a large impact current and affect the stability and reliability of the power plant system.

[0005] In a first aspect, embodiments of the present application provide a power plant black start method based on an energy storage system. The energy storage system includes a plurality of parallel energy storage converters. The power plant black start method based on the energy storage system includes the following steps.

[0006] All energy storage converters in the energy storage system are controlled to be shut down, and all energy storage converters in the energy storage system are controlled to be switched to an off-grid VSG state.

[0007] A first energy storage converter is controlled to start in a voltage slow rise manner. The first energy storage converter is any one of the energy storage converters in the energy storage system.

[0008] After the first energy storage converter is started, each energy storage converter in the energy storage system except the first energy storage converter is controlled to be started in turn.

[0009] In the starting process and after the starting is completed, the energy storage converters in the energy storage system supply power to the motors of the power plant, so that the motors drive the power generation equipment to start and restore power supply of the power grid.

[0010] In a possible implementation manner, the control of each energy storage converter in the energy storage system except the first energy storage converter to be started in turn includes the following steps.

[0011] The other energy storage converters in the energy storage system are sequentially started in a voltage slow rise manner except the first energy storage converter.

[0012] In a possible implementation, the energy storage converter in the energy storage system completes the parallel operation process in the off-grid VSG state.

[0013] In a possible implementation, before the step of controlling all the energy storage converters in the energy storage system to shut down, the power plant black start method based on the energy storage system further includes:

[0014] The step of controlling all the energy storage converters in the energy storage system to shut down is executed.

[0015] When the power grid anomaly is detected and the black start start instruction sent by the EMS is received, the step of controlling all the energy storage converters in the energy storage system to shut down is continued to be executed.

[0016] In a possible implementation, the power plant black start method based on the energy storage system further includes:

[0017] In the black start process, if the black start end instruction sent by the EMS is received, the black start is stopped, and after a delay preset time length, the step of controlling all the energy storage converters in the energy storage system to be in the standby state is continued to be executed.

[0018] In a possible implementation, the power plant black start method based on the energy storage system further includes:

[0019] In the process of starting the energy storage converters in the energy storage system, if a certain energy storage converter cannot be started, the energy storage converter is skipped, and the next energy storage converter is controlled to start.

[0020] After the starting of all the energy storage converters in the energy storage system is completed, if the number of the energy storage converters successfully started in the energy storage system is less than a preset number, it is determined that the black start fails.

[0021] In a second aspect, an embodiment of the present application provides a power plant black start device based on an energy storage system, the energy storage system including a plurality of parallel energy storage converters, and the power plant black start device based on the energy storage system including:

[0022] The state switching module is configured to control all the energy storage converters in the energy storage system to shut down and control all the energy storage converters in the energy storage system to switch to the off-grid VSG state.

[0023] The first starting module is configured to control the first energy storage converter to start in a voltage slow rise manner; and the first energy storage converter is any one of the energy storage converters in the energy storage system.

[0024] The second starting module is configured to control each of the energy storage converters except the first energy storage converter to start in sequence after the first energy storage converter is started.

[0025] In the starting process and after the starting is completed, the energy storage converters in the energy storage system supply power to the motor of the power plant, so that the motor drives the power generation equipment to start and the power grid is restored.

[0026] In a third aspect, an embodiment of the present application provides a coordination controller, including a processor and a memory, the memory is configured to store a computer program, and the processor is configured to call and run the computer program stored in the memory to execute the black start method of the power plant based on the energy storage system as described in the first aspect or any possible implementation manner of the first aspect.

[0027] In a fourth aspect, an embodiment of the present application provides a black start system of a power plant, including an energy storage system, power generation equipment, a switch, an EMS and the coordination controller as described in the third aspect; the energy storage system includes a plurality of energy storage converters connected in parallel;

[0028] The energy storage system, the power generation equipment and the EMS are connected with the coordination controller; a first end of the switch is connected with the energy storage system, a second end of the switch is connected with the power generation equipment; and the switch is controlled by the coordination controller.

[0029] In a fifth aspect, an embodiment of the present application provides a computer readable storage medium, the computer readable storage medium stores a computer program, and the computer program is executed by a processor to implement the steps of the black start method of the power plant based on the energy storage system as described in the first aspect or any possible implementation manner of the first aspect.

[0030] The embodiment of the present application provides a black start method, device and coordination controller of a power plant based on an energy storage system, the first energy storage converter is started in a voltage slow starting mode, and then each of the other energy storage converters is started in sequence, so that the output voltage of the energy storage system gradually increases from zero, the voltage input to the load also gradually increases from zero, and a large voltage is not input instantaneously, thus, a large impact current is not brought to the system, and the stability and reliability of the power plant system can be improved; and the energy storage converter is controlled to switch to an off-grid VSG state, and each of the energy storage converters is controlled to complete parallel operation in the state. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative labor.

[0032] Figure 1 is a structural schematic diagram of a power plant black start system provided by an embodiment of the present application;

[0033] Figure 2 is an implementation flowchart of a power plant black start method based on an energy storage system provided by an embodiment of the present application;

[0034] Figure 3 is a sequential schematic diagram of synchronizing the output voltage of the energy storage system and the output voltage of the power generation equipment provided by an embodiment of the present application;

[0035] Figure 4 is a structural schematic diagram of a power plant black start device based on an energy storage system provided by an embodiment of the present application;

[0036] Figure 5 is a schematic diagram of a coordination controller provided by an embodiment of the present application. DETAILED DESCRIPTION

[0037] In the following description, specific details are set forth, such as a particular system architecture, techniques, etc., in order to provide a thorough understanding of the embodiments of the present application. However, persons skilled in the art will understand that the present application can be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

[0038] In order to make the objectives, technical solutions and advantages of the present application clearer, the following will be described by specific embodiments in conjunction with the accompanying drawings.

[0039] Referring to Figure 1 , a structural schematic diagram of a power plant black start system provided by an embodiment of the present application is shown. The power plant black start system is a system for assisting a 9E level joint high-power power generation equipment to perform black start by a large-capacity energy storage system. Referring to Figure 1 , the power plant black start system includes an energy storage system, a power generation equipment, a switch, an EMS (Energy Management System) and a coordination controller; the energy storage system includes a plurality of parallelly connected power conversion systems (PCSs);

[0040] The energy storage system, the power generation equipment and the EMS are all connected with the coordination controller; a first end of the switch is connected with the energy storage system, and a second end of the switch is connected with the power generation equipment; the switch is controlled by the coordination controller.

[0041] In the formula, U Figure 1 , U PCS may represent the output voltage of the energy storage system, UG The output voltage of the power generation device can be represented. The power generation device can be a high-power power generation device, such as a high-power gas turbine unit or a high-power hydroelectric unit, and the like.

[0042] The EMS can send a black start start instruction and a black start end instruction to the coordination controller. After receiving the black start start instruction, the coordination controller can control the energy storage system to perform black start when detecting a power grid anomaly, such as power failure, so that the energy storage system can supply power to the motor of the power generation device to drive the motor to start the power generation device. After the power generation device is successfully started, the coordination controller controls the power generation device and the energy storage system to be synchronized, i.e., controls the output voltages of the two to be the same in voltage, frequency and phase, so that the output voltages of the two are completely consistent, and finally controls the switch to be attracted, so that the power generation device is put into operation. When the coordination controller receives the black start end instruction, it stops black start, and after a delay for a preset time, it can start black start again when it receives the black start start instruction sent by the EMS and detects that the power grid is still abnormal.

[0043] The switch can be a relay. The coordination controller can be used to perform the following Figure 2 The black start method of the power plant based on the energy storage system of the embodiment shown.

[0044] Referring to Figure 2 which shows the implementation flowchart of the black start method of the power plant based on the energy storage system provided by the embodiment, and the execution subject of the black start method of the power plant based on the energy storage system is a coordination controller. The energy storage system includes a plurality of parallel energy storage converters.

[0045] The method is described in detail as follows:

[0046] In S101, all energy storage converters in the energy storage system are controlled to shut down, and all energy storage converters in the energy storage system are controlled to switch to an off-grid VSG (Virtual Synchronous Generator) state.

[0047] In this embodiment, all energy storage converters in the energy storage system are first controlled to shut down and switch to the off-grid VSG state, so that after each energy storage converter is started, the parallel process is completed.

[0048] In S102, the first energy storage converter is controlled to start in a voltage slow rise manner; the first energy storage converter is any one of the energy storage converters of the energy storage system.

[0049] The voltage slow rise means that the output voltage gradually increases from 0 and does not increase instantaneously. That is, the output voltage of the first energy storage converter gradually increases from 0, so that the transformer in the power plant system is not instantaneously put into a large voltage, avoiding a large impact current.

[0050] The first energy storage converter can be any one of the energy storage converters of the energy storage system, for example, can be the energy storage converter with the smallest or largest number according to the numbering, or can be determined by other rules, which is not specifically limited here.

[0051] The embodiment does not specifically limit the implementation means of controlling the first energy storage converter to start in a voltage slow-rising manner, and any existing implementable method can be used for implementation.

[0052] In S103, after the first energy storage converter is started, each energy storage converter in the energy storage system except the first energy storage converter is sequentially started; wherein, the energy storage converter in the energy storage system supplies power to the motor of the power plant during the starting process and after the starting is completed, so that the motor drives the power generation equipment to start and restores the power supply of the power grid.

[0053] In the embodiment, after the first energy storage converter is started, each energy storage converter in the energy storage system except the first energy storage converter is sequentially started, so that the power and current of the energy storage system put into the power plant system can not be instantaneously increased, but gradually increased, which can improve the system stability and reliability.

[0054] The sequence of sequentially starting each energy storage converter can be in the order from small to large or from large to small according to the number of each energy storage converter, or can be other sequences, which is not specifically limited here.

[0055] The energy storage converter in the energy storage system supplies power to the motor of the power plant during the starting process and after the starting is completed, which means that the energy storage converter is put into the power plant system as soon as it starts, instead of being put into the power plant system after the starting is completed, so that the voltage of the put-in energy storage converter gradually increases from small to large, instead of suddenly increasing, avoiding the occurrence of impulse current.

[0056] After the energy storage converter starts, it can supply power to the motor of the power generation equipment, which can drive the power generation equipment to start, and then the power grid can be restored through the power generation equipment.

[0057] In some possible implementations, the energy storage converter in the energy storage system can also supply power to other loads of the power plant during the starting process and after the starting is completed, which is not specifically limited here.

[0058] The embodiment can gradually increase the output voltage of the energy storage system from zero, gradually increase the voltage input to the load from zero, not instantaneously input a large voltage, thus not bring a large impact current to the system, and improve the stability and reliability of the power plant system; and by controlling the energy storage converter to switch to the off-grid VSG state, each energy storage converter can complete parallel operation in the state.

[0059] In some embodiments, the step of controlling each energy storage converter in the energy storage system except the first energy storage converter to start in sequence in S103 can include:

[0060] Controlling each energy storage converter in the energy storage system except the first energy storage converter to start in sequence in a voltage slow start manner.

[0061] In the embodiment, the manner of controlling each energy storage converter in the energy storage system except the first energy storage converter to start can be the same as the manner of controlling the first energy storage converter to start, that is, starting in a voltage slow start manner, so that the power and current input to the power plant system can be gradually and slowly increased, and the system stability and reliability can be further improved.

[0062] In some embodiments, the energy storage converter in the energy storage system completes the parallel operation process in the off-grid VSG state.

[0063] In the embodiment, after the energy storage converter in the energy storage system starts successfully, the energy storage converter can achieve power sharing with other energy storage converters in the off-grid VSG state, and complete the parallel operation process.

[0064] In some embodiments, before S101, the black start method of the power plant based on the energy storage system further includes:

[0065] Controlling all energy storage converters of the energy storage system to be in a standby state;

[0066] When detecting that the power grid is abnormal and receiving a black start start instruction sent by the EMS, continuing to control all energy storage converters in the energy storage system to shut down.

[0067] In the embodiment, the coordination controller can first control all energy storage converters of the energy storage system to be in a standby state, when receiving a black start start instruction sent by the EMS and detecting that the power grid is abnormal, control all energy storage converters in the energy storage system to shut down, and then control each energy storage converter to start in sequence.

[0068] The power grid can be determined to be abnormal when the voltage of the power grid is lower than a preset voltage value, and otherwise, the power grid is determined to be normal.

[0069] The EMS can send the black start start instruction according to human control, or send the black start start instruction after detecting that the power plant system is disconnected from the power grid, and the like.

[0070] In some possible implementation manners, the coordination controller can control all the energy storage converters of the energy storage system to be in the standby state after detecting that the power plant system is disconnected from the power grid.

[0071] In some embodiments, the power plant black start method based on the energy storage system further includes:

[0072] In the black start process, if the black start end instruction sent by the EMS is received, the black start is stopped, and after a preset time delay, the step of controlling all the energy storage converters of the energy storage system to be in the standby state is continued to be executed.

[0073] The EMS can send the black start end instruction according to human control, or send the black start end instruction after detecting that the black start process has a problem and cannot continue, and the like.

[0074] In the black start process, if the black start end instruction sent by the EMS is received by the coordination controller, it indicates that the black start should be stopped at this time, at this time, the control of starting the energy storage converter can be stopped, and after a preset time delay, the step of controlling all the energy storage converters of the energy storage system to be in the standby state is continued to be executed, and the black start can be restarted.

[0075] The preset time delay can be set according to actual needs, for example, can be 30s, and the like.

[0076] The embodiment can prevent the phenomenon of being stuck in the black start process through the black start end instruction.

[0077] In some embodiments, the power plant black start method based on the energy storage system further includes:

[0078] In the process of starting each energy storage converter in the energy storage system, if a certain energy storage converter cannot be started, the energy storage converter is skipped, and the next energy storage converter is controlled to be started;

[0079] After all the energy storage converters of the energy storage system are started, if the number of the energy storage converters successfully started in the energy storage system is less than a preset number, it is determined that the black start fails.

[0080] In the process of starting each energy storage converter in the energy storage system, if a certain energy storage converter cannot be started due to no battery or other fault reasons, the energy storage converter is skipped, and the next energy storage converter is controlled to continue to be started, to prevent the situation that the execution cannot continue due to the existence of the faulty energy storage converter.

[0081] Regardless of whether the energy storage converter is successfully started or fails to start due to a fault, it is considered that the starting is completed. When all the energy storage converters in the energy storage system are started, if the number of the energy storage converters successfully started in the energy storage system is less than the preset number, it is determined that the black start fails, and the next black start step cannot be executed. The staff can be notified to repair the failed energy storage converter. If the power grid is still abnormal after the repair, the black start is continued. If the number of the energy storage converters successfully started in the energy storage system is not less than the preset number, it is determined that the energy storage system is successfully started.

[0082] The preset number is less than the total number of the energy storage converters in the energy storage system. For example, the total number of the energy storage converters in the energy storage system can be 18, and the preset number can be 16.

[0083] In some possible implementation manners, the black start method of the power plant of the energy storage system can further include:

[0084] After each energy storage converter in the energy storage system is successfully started, power sharing control is performed on the energy storage converter to realize non-communication parallel operation.

[0085] In some possible implementation manners, the power sharing control performed on the energy storage converter to realize non-communication parallel operation can include:

[0086] An active power reference value of the energy storage converter is obtained based on a droop characteristic of active power and frequency;

[0087] An angular frequency reference value of the energy storage converter is determined according to the active power given value based on virtual inertia;

[0088] A voltage amplitude reference value of the energy storage converter is obtained based on a droop characteristic of reactive power and voltage;

[0089] A voltage reference value of the energy storage converter is generated according to the voltage amplitude reference value and the angular frequency reference value;

[0090] Voltage loop and current loop control is performed on the energy storage converter based on the voltage reference value to realize non-communication parallel operation.

[0091] Based on the VSG, the application realizes non-communication line off-grid parallel operation of multiple energy storage converters, and drives the motor of the power generation equipment to start. Under the large load of the motor of the power generation equipment, the system can still stably operate.

[0092] The VSG is a control strategy for simulating the motion equation of the rotor of the synchronous generator, the active power-frequency (P-F) droop characteristic and the reactive power-voltage (Q-V) droop characteristic, starting from the correspondence between the main circuit of the grid-connected inverter and the equivalent circuit of the synchronous generator.

[0093] This embodiment determines the active power reference value of the energy storage converter based on the droop characteristics of active power and frequency. By using virtual inertia, specifically virtual rotational inertia, the drop in active power and the rise in active power are slowed down, resulting in more stable active power. Based on the QV droop characteristics, the voltage amplitude reference value of the energy storage converter can be determined. According to the voltage reference value, dual closed-loop control of the energy storage converter (voltage loop and current loop) can be implemented, ultimately achieving power sharing among the energy storage converters and communication-free parallel operation.

[0094] In some possible implementations, obtaining the active power reference value of the energy storage converter based on the droop characteristics of active power and frequency can include:

[0095] Obtain the angular frequency sampling value ω of the energy storage converter fdb And based on the rated angular frequency ω0 and the angular frequency sample value ω of the energy storage converter fdb The angular frequency difference is obtained.

[0096] The active power adjustment is obtained based on the angular frequency difference.

[0097] The active power reference value is obtained based on the active power adjustment and the rated active power P0 of the energy storage converter.

[0098] The angular frequency difference is obtained by subtracting the sampled angular frequency value ω from the rated angular frequency ω0. Based on the angular frequency difference and the active power droop coefficient M, the active power adjustment is obtained. The active power adjustment is then added to the rated active power P0 to obtain the active power reference value.

[0099] In some possible implementations, the above-mentioned determination of the angular frequency reference value of the energy storage converter based on virtual inertia and the given active power value may include:

[0100] Obtain the active power sample value P of the energy storage converter fdb Based on the active power reference value and the active power sample value P fdb The difference in active power is obtained.

[0101] The angular frequency adjustment is obtained based on the difference in active power.

[0102] Based on the angular frequency adjustment and the rated angular frequency ω0 of the energy storage converter, the angular frequency reference value ω is obtained. REF .

[0103] Active power reference value minus active power sample value P fdb The active power difference is obtained. Based on the active power difference and related parameters of virtual inertia... The angular frequency adjustment amount is obtained. Adding the angular frequency adjustment amount to the rated angular frequency ω0 yields the angular frequency reference value ω. REF.in, Let be the transfer function of the inertial element. In the prior art, the transfer function of the inertial element is usually . In this embodiment, to provide a smaller moment of inertia, it is modified to... K D A coefficient greater than 1.

[0104] In some possible implementations, obtaining the voltage amplitude reference value of the energy storage converter based on the reactive power and voltage droop characteristics can include:

[0105] Obtain the reactive power reference value Q of the energy storage converter REF and reactive power sampling value Q fdb And based on the reactive power reference value Q REF and reactive power sampling value Q fdb The reactive power difference is obtained.

[0106] The voltage amplitude adjustment amount is obtained based on the reactive power difference;

[0107] Based on the voltage amplitude adjustment and the rated voltage amplitude U0 of the energy storage converter, the voltage amplitude reference value U is obtained. REF .

[0108] Reactive power reference value Q REF Subtract the reactive power sample value Q fdb The reactive power difference is obtained. Based on the reactive power difference and the reactive power droop coefficient N, the voltage amplitude adjustment is obtained. The voltage amplitude adjustment is added to the rated voltage amplitude U0 to obtain the voltage amplitude reference value U. REF .

[0109] In some possible implementations, generating the voltage reference value for the energy storage converter based on the voltage amplitude reference value and the angular frequency reference value may include:

[0110] According to the angular frequency reference value ω REF Determine the phase reference value

[0111] According to the voltage amplitude reference value U REF and phase reference value Generate the voltage reference value for the energy storage converter.

[0112] Reference value of angular frequency ω REF Perform an integration operation to obtain the phase reference value. According to the voltage amplitude reference value U REF and phase reference value It can generate voltage reference values ​​for energy storage converters.

[0113] In some possible implementations, the voltage loop and current loop control of the energy storage converter based on the voltage reference value can include:

[0114] The dq coordinate transformation is performed on the voltage reference value to obtain a d-axis reference voltage U d and a q-axis reference voltage U q .

[0115] The voltage loop and current loop control are performed on the d-axis reference voltage U d to obtain a first control quantity.

[0116] The voltage loop and current loop control are performed on the q-axis reference voltage U q to obtain a second control quantity.

[0117] The first control quantity and the second control quantity are subjected to SVPWM (Space Vector Pulse Width Modulation) modulation to obtain a PWM wave, and the energy storage converter is controlled according to the PWM wave.

[0118] The dq coordinate transformation can also be a Park transformation.

[0119] The dq coordinate transformation is performed on the voltage reference value to obtain a d-axis reference voltage U d and a q-axis reference voltage U q .

[0120] The d-axis reference voltage U d is subtracted from a d-axis sampling voltage U dfdb to obtain a d-axis voltage difference, and the voltage loop PI control is performed on the d-axis voltage difference to obtain a d-axis reference current I d , and the d-axis reference current I d is subtracted from a d-axis sampling current I dfdb to obtain a d-axis current difference, and the current loop PI control is performed on the d-axis current difference to obtain a third control quantity, and the third control quantity is added to U d / 1.732 to obtain a fourth control quantity, and the fourth control quantity is normalized to 0 to 1 to obtain the first control quantity.

[0121] The q-axis reference voltage U q is subtracted from a q-axis sampling voltage U qfdb to obtain a q-axis voltage difference, and the voltage loop PI control is performed on the q-axis voltage difference to obtain a q-axis reference current I q , and the q-axis reference current I q is subtracted from a q-axis sampling current I qfdb to obtain a q-axis current difference, and the current loop PI control is performed on the q-axis current difference to obtain a fifth control quantity, and the fifth control quantity is added to U q / 1.732, the sixth control variable is obtained. The sixth control variable is normalized to between 0 and 1 to obtain the second control variable.

[0122] By performing SVPWM modulation on the first and second control variables, a PWM wave can be obtained, which is used to control the energy storage converter.

[0123] Among them, the d-axis sampling voltage U dfdb and q-axis sampling voltage U qfdb It can be obtained by performing a dq coordinate transformation based on the voltage sampling value of the energy storage converter. The d-axis reference current I... d and q-axis reference current I q This can be obtained by performing a dq coordinate transformation based on the current reference value of the energy storage converter. The d-axis sampling current I... dfdb and q-axis sampling current I qfdb It can be obtained by performing a dq coordinate transformation based on the current sampling value of the energy storage converter.

[0124] This application achieves power sharing and stable operation by applying the same control to each energy storage converter in the energy storage system, and by adding droop control and rotational inertia to the dual closed-loop control. Specifically, multiple converters are connected in parallel with the same droop coefficient, and the angular frequency and voltage are adjusted through droop control. After a period of adjustment, the output voltage and frequency of each energy storage converter tend to be consistent, ultimately achieving the goal of equal distribution of active and reactive power. At the same time, virtual inertia is added to ensure the stable operation of the system during dynamic processes, enabling the stable operation of multiple energy storage converters under the high load of the generator motor (10MW impact), with small voltage fluctuations and even power distribution, which improves the reliability of the system, and enables communication-free parallel operation with fast response speed and no communication interference.

[0125] In some possible implementations, after S103 above, the power plant black start method of the energy storage system may further include:

[0126] After all energy storage converters in the energy storage system have started up, if the number of energy storage converters successfully started in the energy storage system is not less than the preset number, the output voltage of the power generation equipment is obtained.

[0127] If the output voltage of the power generation equipment is within the preset voltage range, the output voltage of the energy storage system is obtained, and the output voltage of the energy storage system is adjusted according to the output voltage of the power generation equipment to make the output voltage of the energy storage system and the output voltage of the power generation equipment the same in voltage, frequency and phase. After the output voltage of the energy storage system and the output voltage of the power generation equipment are the same in voltage, frequency and phase, the power generation equipment is controlled to be connected to the grid.

[0128] When the number of successfully started energy storage converters in the energy storage system is not less than the preset number, it can be considered that the energy storage system black start is successful. After the energy storage system black start is successful, the power generation equipment is started, and whether the power generation equipment is successfully started is judged by detecting whether the output voltage of the power generation equipment is in the preset voltage range.

[0129] The preset voltage range can be a voltage range in which the output voltage of the power generation equipment is located after the power generation equipment is successfully started, and can be determined according to actual experiments. When the output voltage of the power generation equipment is in the preset voltage range, it can be considered that the power generation equipment has been successfully started, and at this time, the output voltage of the energy storage system and the output voltage of the power generation equipment are started to be synchronized. When the output voltage of the power generation equipment is not in the preset voltage range, it can be considered that the power generation equipment has not been successfully started, and can still be in the process of building pressure. At this time, the output voltage of the power generation equipment can be continuously monitored until the output voltage is in the preset voltage range, and then the process of synchronizing the output voltage of the energy storage system and the output voltage of the power generation equipment is continued.

[0130] The embodiment does not make specific limitations on the specific means by which the coordination controller obtains the output voltage of the power generation equipment and the output voltage of the energy storage system, and any implementable manner can be adopted.

[0131] The embodiment adjusts the output voltage of the energy storage system through the output voltage of the power generation equipment, so that the output voltage of the energy storage system and the output voltage of the power generation equipment are the same in voltage, frequency and phase, that is, the output of the energy storage system and the power generation equipment is kept consistent, so that a large impact current can be avoided when the power generation equipment is put into operation. After detecting that the output voltage of the energy storage system and the output voltage of the power generation equipment are the same in voltage, frequency and phase, the power generation equipment can be controlled to be connected to the power grid, and stable and reliable seamless switching can be realized.

[0132] The embodiment adjusts the output voltage of the energy storage system according to the output voltage of the power generation equipment, so that the output voltage of the energy storage system and the output voltage of the power generation equipment are the same in voltage, frequency and phase, so that the output voltage of the energy storage system and the power generation equipment is completely consistent, and then the power generation equipment is controlled to be connected to the power grid, which can avoid a large impact current after the power generation equipment is connected to the power grid, and stable and reliable seamless switching can be realized, and the system stability can be improved.

[0133] In some possible implementation manners, the above adjusting the output voltage of the energy storage system according to the output voltage of the power generation equipment, so that the output voltage of the energy storage system and the output voltage of the power generation equipment are the same in voltage, frequency and phase, can include:

[0134] The difference of effective values of the output voltage of the power generation device and the output voltage of the energy storage system is obtained, and the size of the output voltage of the energy storage system is adjusted according to the difference of effective values, so that the output voltage of the energy storage system and the output voltage of the power generation device are the same voltage.

[0135] The difference of frequencies of the output voltage of the power generation device and the output voltage of the energy storage system is obtained, and the frequency of the output voltage of the energy storage system is adjusted according to the difference of frequencies, so that the output voltage of the energy storage system and the output voltage of the power generation device are the same frequency.

[0136] The difference of phases of the output voltage of the power generation device and the output voltage of the energy storage system is obtained, and the phase of the output voltage of the energy storage system is adjusted according to the difference of phases, so that the output voltage of the energy storage system and the output voltage of the power generation device are the same phase.

[0137] Referring to Figure 3 When synchronizing the output voltage of the energy storage system and the output voltage of the power generation device, the same voltage can be performed first, then the same frequency, and finally the same phase, so that the output of the two is completely consistent. Among them, U PCS represents the output voltage of the energy storage system, U G represents the output voltage of the power generation device.

[0138] The coordination controller collects the output voltage of the power generation device and the output voltage of the energy storage system, respectively calculates the difference of the size, frequency and phase of the voltage of the two, and transmits the difference to the energy storage system through 485 communication or other communication mode as the basis for voltage compensation of the energy storage system. The energy storage system adjusts the size, frequency and phase of the output voltage according to the received difference, and finally makes the voltage of the energy storage system and the power generation device consistent.

[0139] Specifically, due to the influence of the Q-V droop curve in the system, the voltage size will be offset according to the different reactive power. In order to ensure that the output voltage of the energy storage system is synchronized with the grid, the output voltage size of the energy storage system needs to be adjusted according to the difference of effective values, so as to realize the same voltage in the synchronization function.

[0140] Due to the influence of the P-F droop curve in the system, the voltage frequency will be offset according to the different active power. The voltage frequency of the energy storage system and the power generation device is calculated respectively according to the phase-locked loop in the coordination controller, and the difference of the two is used as the basis for adjusting the frequency of the energy storage system, so as to compensate the frequency of the output voltage, so as to realize the same frequency in the synchronization function.

[0141] The phase of the output voltage of the energy storage system and the power generation device is calculated respectively according to the phase-locked loop in the coordination controller, and the difference of the two is used as the basis for adjusting the phase direction of the energy storage system, so as to adjust the phase of the output voltage of the energy storage system.

[0142] The embodiment can achieve the purpose of adjusting the phase by adjusting the frequency. When the phases are finally adjusted to be consistent, the frequencies are also consistent.

[0143] In some possible implementation manners, the adjusting the phase of the output voltage of the energy storage system according to the phase difference value, so that the output voltage of the energy storage system and the output voltage of the power generation device are in phase, includes:

[0144] The phase of the output voltage of the energy storage system is adjusted according to the phase difference value in a fixed step, so that the output voltage of the energy storage system and the output voltage of the power generation device are in phase.

[0145] The fixed step adjustment can be understood as adjusting the phase by a preset step each time, that is, adjusting step by step by the preset step, instead of adjusting to the right place at one time.

[0146] In some possible implementation manners, the energy storage system includes a plurality of energy storage converters connected in parallel.

[0147] The adjusting the size of the output voltage of the energy storage system according to the effective value difference, so that the output voltage of the energy storage system and the output voltage of the power generation device are in pressure, includes:

[0148] The effective value difference is sent to each energy storage converter in the energy storage system in a broadcast manner, so that the energy storage converter adjusts the size of the output voltage of the energy storage converter according to the effective value difference, so that the output voltage of the energy storage system and the output voltage of the power generation device are in pressure.

[0149] The adjusting the frequency of the output voltage of the energy storage system according to the frequency difference value, so that the output voltage of the energy storage system and the output voltage of the power generation device are in frequency, includes:

[0150] The frequency difference value is sent to each energy storage converter in the energy storage system in a broadcast manner, so that the energy storage converter adjusts the frequency of the output voltage of the energy storage converter according to the frequency difference value, so that the output voltage of the energy storage system and the output voltage of the power generation device are in frequency.

[0151] The adjusting the phase of the output voltage of the energy storage system according to the phase difference value, so that the output voltage of the energy storage system and the output voltage of the power generation device are in phase, includes:

[0152] The phase difference value is sent to each energy storage converter in the energy storage system in a broadcast manner, so that the energy storage converter adjusts the phase of the output voltage of the energy storage converter according to the phase difference value, so that the output voltage of the energy storage system and the output voltage of the power generation device are in phase.

[0153] In the embodiment, since the energy storage system comprises a plurality of energy storage converters connected in parallel, in order to ensure consistency of voltage compensation values received by all energy storage converters and synchronization of frequency modulation and voltage regulation, during the synchronization process, the coordination controller sends information to the energy storage converters in a broadcast manner, so as to avoid different compensation of the energy storage converters.

[0154] Before the synchronization, the coordination controller and the PCS can communicate through point-to-point communication, for example, through point-to-point communication, the PCS is controlled to start black start, switch on, state switching and the like.

[0155] In some possible implementation manners, referring to Figure 1 , the energy storage system is connected with the power generation device through a switch, and the energy storage system, the switch and the power generation device are controlled by the coordination controller;

[0156] Controlling the power generation device to be connected to the power grid comprises:

[0157] Controlling the switch to be attracted.

[0158] Referring to Figure 1 , after the synchronization is completed, the power generation device can be controlled to be connected to the power grid by controlling the switch to be attracted.

[0159] It should be understood that the sequence numbers of the steps in the above embodiment do not mean the execution sequence, the execution sequence of the processes should be determined according to the functions and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the application.

[0160] Figure 4 A structure schematic diagram of the black start device of the power plant based on the energy storage system provided by the embodiment of the application is shown, only parts related to the embodiment of the application are shown for the convenience of description, and the details are as follows:

[0161] The energy storage system comprises a plurality of energy storage converters connected in parallel. As Figure 4 shown, the black start device of the power plant based on the energy storage system 30 comprises a state switching module 31, a first start module 32 and a second start module 32.

[0162] The state switching module 31 is configured to control all energy storage converters in the energy storage system to be shut down and control all energy storage converters in the energy storage system to be switched to an off-grid VSG state.

[0163] The first start module 32 is configured to control a first energy storage converter to start in a voltage slow start manner; the first energy storage converter is any one of the energy storage converters of the energy storage system.

[0164] The second starting module 33 is configured to control each of the energy storage converters in the energy storage system except the first energy storage converter to start in sequence after the first energy storage converter is started.

[0165] In the starting process and after the starting is completed, the energy storage converter in the energy storage system supplies power to the motor of the power plant, so that the motor drives the power generation equipment to start and restore the power supply of the power grid.

[0166] In a possible implementation, the second starting module 33 is specifically configured to:

[0167] After the first energy storage converter is started, the second starting module 33 is configured to control each of the energy storage converters in the energy storage system except the first energy storage converter to start in sequence in a voltage slow start manner.

[0168] In a possible implementation, the energy storage converter in the energy storage system completes the parallel operation process in the off-grid VSG state.

[0169] In a possible implementation, the black start device 30 for the power plant based on the energy storage system further includes a pre-control module.

[0170] The pre-control module is configured to:

[0171] Control all the energy storage converters in the energy storage system to be in a standby state.

[0172] When the power grid is detected to be abnormal and the black start start instruction sent by the EMS is received, the step of controlling all the energy storage converters in the energy storage system to shut down is continued to be executed.

[0173] In a possible implementation, the black start device 30 for the power plant based on the energy storage system further includes a black start restart module.

[0174] The black start restart module is configured to:

[0175] During the black start process, if the black start end instruction sent by the EMS is received, the black start is stopped, and after a delay for a preset time length, the step of controlling all the energy storage converters in the energy storage system to be in the standby state is continued to be executed.

[0176] In a possible implementation, the black start device 30 for the power plant based on the energy storage system further includes a black start judgment module.

[0177] The black start judgment module is configured to:

[0178] During the starting process of each of the energy storage converters in the energy storage system, if a certain energy storage converter cannot be started, the energy storage converter is skipped, and the next energy storage converter is controlled to start.

[0179] If the number of successfully started energy storage converters in the energy storage system is less than the preset number after all energy storage converters in the energy storage system have been started, then the black start is determined to have failed.

[0180] Figure 5 This is a schematic diagram of the coordination controller provided in an embodiment of the present invention. Figure 5 As shown, the coordination controller 4 in this embodiment includes a processor 40 and a memory 41. The memory 41 stores a computer program 42, and the processor 40 calls and runs the computer program 42 stored in the memory 41 to execute the steps in the various embodiments of the power plant black-start method based on energy storage systems described above, for example... Figure 2 S101 to S103 are shown. Alternatively, the processor 40 is used to call and run the computer program 42 stored in the memory 41 to implement the functions of each module / unit in the above-described device embodiments, for example... Figure 4 The functions of modules / units 31 to 33 shown.

[0181] For example, the computer program 42 can be divided into one or more modules / units, which are stored in the memory 41 and executed by the processor 40 to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program 42 in the coordination controller 4. For example, the computer program 42 can be divided into... Figure 4 Modules / units 31 to 33 are shown.

[0182] The coordination controller 4 may include, but is not limited to, a processor 40 and a memory 41. Those skilled in the art will understand that... Figure 5 This is merely an example of the coordination controller 4 and does not constitute a limitation on it. It may include more or fewer components than illustrated, or combine certain components, or use different components. For example, the coordination controller may also include input / output devices, network access devices, buses, etc. For instance, the coordination controller may also include the aforementioned DMS and OMS, etc.

[0183] The processor 40 can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0184] The memory 41 can be an internal storage unit of the coordination controller 4, such as a hard disk or a memory of the coordination controller 4. The memory 41 can also be an external storage device of the coordination controller 4, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. Further, the memory 41 can include both the internal storage unit and the external storage device of the coordination controller 4. The memory 41 is used to store the computer program and other programs and data required by the coordination controller. The memory 41 can also be used to temporarily store data that has been output or is to be output.

[0185] Corresponding to the above coordination controller, the embodiment of the present application also provides a power plant black start system, comprising the coordination controller according to any one of the above, further comprising an energy storage system, a power generation device, a switch and an EMS; the energy storage system comprises a plurality of energy storage converters connected in parallel;

[0186] The energy storage system, the power generation device and the EMS are connected with the coordination controller; the first end of the switch is connected with the energy storage system, and the second end of the switch is connected with the power generation device; the switch is controlled by the coordination controller.

[0187] The related description of the power plant black start system can refer to the description in the above embodiment, and will not be repeated here.

[0188] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the above-mentioned division of each functional unit and module is exemplified, and in actual application, the above-mentioned functions can be completed by different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be realized in the form of hardware or software. In addition, the specific name of each functional unit and module is only for the convenience of mutual distinction, and does not limit the protection scope of the present application. The specific working process of the unit and module in the above system can be referred to the corresponding process in the foregoing method embodiment, which will not be described here.

[0189] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described or recorded in detail in a certain embodiment can be referred to the related description of other embodiments.

[0190] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized in electronic hardware or a combination of computer software and electronic hardware. Whether the functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. A person skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0191] In the embodiments provided by the present application, it should be understood that the disclosed device / coordination controller and method can be implemented by other ways. For example, the above-mentioned device / coordination controller embodiments are only schematic, and the division of the modules or units is only a logical function division, and there can be another division way in actual implementation, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual coupling or direct coupling or communication connection between interfaces can be indirect coupling or communication connection through some interfaces, devices or units, and can be electrical, mechanical or other forms.

[0192] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed on a plurality of network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0193] In addition, each function unit in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software function unit.

[0194] The integrated module / unit, if realized in the form of a software function unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the above-mentioned embodiment methods can also be completed by a computer program instructing related hardware, and the computer program can be stored in a computer-readable storage medium. When the processor executes the computer program, the steps of each of the above-mentioned energy storage system-based power plant black start method embodiments can be implemented. The computer program includes computer program code, which can be in the form of source code, object code, an executable file, or some intermediate form, etc. The computer-readable medium can include any entity or device capable of carrying the computer program code, a recording medium, a U disk, a mobile hard disk, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc. It should be noted that the contents included in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction, for example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0195] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; 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 method for power plants based on an energy storage system, characterized in that, The energy storage system includes multiple parallel energy storage converters, and the black start method for power plants based on the energy storage system includes: Control all energy storage converters in the energy storage system to shut down, and control all energy storage converters in the energy storage system to switch to off-grid VSG state; The first energy storage converter is controlled to start up in a voltage soft-start manner; the first energy storage converter is any one of the energy storage converters in the energy storage system; the voltage soft-start refers to the output voltage soft-start. After the first energy storage converter is started, control each energy storage converter in the energy storage system except for the first energy storage converter to start in sequence; The energy storage converter in the energy storage system supplies power to the generators of the power plant during and after startup, so that the generators can drive the power generation equipment to start and restore power supply to the grid.

2. The black start method for power plants based on energy storage systems according to claim 1, characterized in that, The control of sequentially starting each energy storage converter in the energy storage system, except for the first energy storage converter, includes: The energy storage system controls each energy storage converter in the system, except for the first energy storage converter, to start up sequentially using a voltage soft-start method.

3. The black start method for power plants based on energy storage systems according to claim 1, characterized in that, The energy storage converter in the energy storage system completes the parallel operation process under the off-grid VSG state.

4. The black start method for power plants based on energy storage systems according to claim 1, characterized in that, Before shutting down all energy storage converters in the energy storage system, the black start method for power plants based on the energy storage system further includes: All energy storage converters in the energy storage system are kept in standby mode. When a grid anomaly is detected and a black start command is received from the EMS, the steps to control the shutdown of all energy storage converters in the energy storage system continue.

5. The black start method for power plants based on energy storage systems according to claim 4, characterized in that, The black start method for power plants based on energy storage systems also includes: During the black start process, if a black start end command is received from the EMS, the black start is stopped, and after a preset delay, the process jumps to the step of controlling all energy storage converters of the energy storage system to be in standby mode and continues to execute.

6. The black start method for power plants based on energy storage systems according to any one of claims 1 to 5, characterized in that, The black start method for power plants based on energy storage systems also includes: During the startup process of each energy storage converter in the energy storage system, if a certain energy storage converter fails to start, the startup of that energy storage converter is skipped and the next energy storage converter is controlled to start. If, after all energy storage converters in the energy storage system have been started, the number of energy storage converters that have been successfully started in the energy storage system is less than a preset number, then a black start is determined to have failed.

7. A black start device for power plants based on an energy storage system, characterized in that, The energy storage system includes multiple parallel energy storage converters, and the power plant black start device based on the energy storage system includes: The state switching module is used to control the shutdown of all energy storage converters in the energy storage system and to control all energy storage converters in the energy storage system to switch to the off-grid VSG state. The first startup module is used to control the first energy storage converter to start up in a voltage soft-start manner; the first energy storage converter is any one of the energy storage converters in the energy storage system; the voltage soft-start refers to the output voltage soft-start. The second startup module is used to control each energy storage converter in the energy storage system, excluding the first energy storage converter, to start sequentially after the first energy storage converter has started. The energy storage converter in the energy storage system supplies power to the generators of the power plant during and after startup, so that the generators can drive the power generation equipment to start and restore power supply to the grid.

8. A coordination controller, characterized in that, It includes a memory and a processor, wherein the memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory to perform the black start method for a power plant based on an energy storage system as described in any one of claims 1 to 6.

9. A black start system for a power plant, characterized in that, It includes an energy storage system, a power generation device, a switch, an EMS, and a coordination controller as described in claim 8; the energy storage system includes multiple energy storage converters connected in parallel; The energy storage system, the power generation equipment, and the EMS are all connected to the coordination controller; the first terminal of the switch is connected to the energy storage system, and the second terminal of the switch is connected to the power generation equipment; the switch is controlled by the coordination controller.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the power plant black start method based on the energy storage system as described in any one of claims 1 to 6 above.

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