Pumped storage unit excitation control device and method with quick response

Abstract

The invention relates to a pumped storage unit excitation control device and method with quick response, and belongs to the technical field of pumped storage unit control, and the method comprises the following steps: constructing an excitation control system based on a parallel structure of a main voltage control ring and a system voltage control ring; the main voltage control loop is formed by parallel PID controllers, and the system voltage control loop is formed by connecting system voltage control loop gain and two-stage lead-lag correction links in series. And a high-voltage side voltage deviation control signal input by the main voltage control ring is superposed with a machine terminal voltage deviation signal, and an excitation control signal is output after the superposed signals pass through a parallel PID (Proportion Integration Differentiation) controller. The voltage loop gain of the system is set according to 5%-10% of the reactive droop characteristic of the high-voltage side of the main transformer, reactive power distribution during parallel connection of the multiple pumped storage units is achieved, and reactive power fluctuation is avoided. And the dynamic quality of the system voltage loop is adjusted through the time constant of the two-stage lead-lag correction link. The system has the capability of quickly responding to the voltage change of the power grid, and can provide quick reactive power support and maintain the voltage stability.

Description

Technical Field

[0001] The present invention relates to a pumped storage unit excitation control device and method with rapid response, belonging to the technical field of pumped storage unit control. Background Art

[0002] Pumped storage units play an important role in the power system. Their main function is to pump water from the lower reservoir to the upper reservoir when the power system load is low, converting electrical energy into water potential energy and storing it; when the power system load is peak, the water in the upper reservoir flows out through the turbine, driving the generator to generate electricity, converting the stored potential energy into electrical energy, thereby regulating the supply and demand balance of the power system and improving the stability and reliability of the power grid.

[0003] Prior art, such as Chinese invention patent application publication number CN115693718A, discloses a power control method, system, and device for a doubly-fed pumped-storage unit. The method comprises: obtaining motor operating parameters of the doubly-fed pumped-storage unit, inputting the motor operating parameters into a preset machine-side control loop model, performing integral transformation on the motor operating parameters using a generalized integral module to obtain output power parameters and rotor current component parameters, performing power regulation processing on the output power parameters via a power loop to obtain a given rotor current reference value, inputting the given rotor current reference value and the rotor current component parameters into a stator flux control module for flux regulation, obtaining machine-side converter control instructions for the doubly-fed pumped-storage unit, and using the machine-side converter control instructions to power regulate the doubly-fed pumped-storage unit. However, the aforementioned patent relies on precise modeling of the generalized integral module and virtual reactance. If parameters such as stator resistance and inductance drift due to temperature or aging, this may lead to accumulated integral errors, affecting the accuracy of the output power parameters. The simulation effect of the virtual reactance depends on the precise matching of grid parameters, which is difficult to maintain stably in complex actual grids. Summary of the Invention

[0004] In order to solve the above problems in the prior art, the present invention proposes a pumped storage unit excitation control device and method with fast response.

[0005] The technical solutions of the present invention are as follows:

[0006] In one aspect, the present invention provides a method for controlling the excitation of a pumped storage unit with rapid response, comprising the following steps:

[0007] Determine the voltage droop slope on the high-voltage side of the main transformer according to the reactive support demand of the pumped-storage power plant in the power grid, and determine the system voltage control loop gain based on the voltage droop slope on the high-voltage side;

[0008] Construct an excitation control system with a dual-loop structure. The dual-loop structure is specifically a parallel structure including a main voltage control loop and a system voltage control loop, wherein:

[0009] The system voltage control loop is composed of a system voltage control loop gain and a two-stage lead-lag correction link connected in series. The input end receives the deviation signal of the reference value and the measured value of the high-voltage side voltage of the main transformer, amplifies it through the system voltage control loop gain, and then corrects it through the two-stage lead-lag link and limits it as the high-voltage side voltage deviation control signal.

[0010] The main voltage control loop is composed of a parallel PID controller, the input end of which receives the deviation signal of the reference value and the measured value of the pumped storage unit terminal voltage, and superimposes it with the high-voltage side voltage deviation control signal. After superposition, it is input into the parallel PID controller for correction calculation and outputs the excitation control signal;

[0011] The excitation control signal is input into the excitation power unit of the pumped storage unit for power amplification, and the excitation control voltage is obtained to control the pumped storage unit.

[0012] Preferably, the excitation control voltage is expressed as:

[0013]

[0014] Where U fd Indicates the excitation control voltage, U g Represents the measured value of the terminal voltage of the pumped storage unit, r g Indicates the reference value of the terminal voltage of the pumped storage unit, r h Indicates the reference value of the high voltage side voltage of the main transformer, U H Indicates the measured value of the high voltage side voltage of the main transformer, K H represents the system voltage control loop gain, s represents a complex variable, T1, T2, T3, T4 represent the time constants of the two-stage lead-lag correction link, K p Represents the proportional gain, K i Indicates the integral gain, K d represents the differential gain, T A Indicates the delay time of the power amplifier link, K A Indicates the gain of the power amplifier link.

[0015] Preferably, the steady-state value of the high-voltage side voltage of the main transformer is expressed as follows:

[0016]

[0017] Where, X t Indicates the per-unit short-circuit impedance of the main transformer, I qIt represents the per unit value of the reactive component of the terminal current of the pumped storage unit.

[0018] Preferably, the steady-state value of the terminal voltage of the pumped storage unit is expressed as follows:

[0019]

[0020] Where, X t Indicates the per-unit short-circuit impedance of the main transformer, I q It represents the per unit value of the reactive component of the terminal current of the pumped storage unit.

[0021] Preferably, the system voltage control loop gain is expressed as:

[0022]

[0023] Where D represents the preset voltage droop slope of the high-voltage side of the main transformer, X t Indicates the per-unit short-circuit impedance of the main transformer.

[0024] Preferably, the method further comprises constructing a single-machine infinite power system simulation model, including a pumped storage unit, an excitation control system, a high-voltage switch, a low-voltage switch, a main transformer, a transmission line, an excitation transformer, a system equivalent impedance, and a system equivalent infinite power supply;

[0025] The pumped storage unit is connected to the low-voltage side of the main transformer through a low-voltage switch, the high-voltage side of the main transformer is connected to one end of the transmission line through a high-voltage switch, and the other end of the transmission line is connected to the system equivalent infinite power supply through the system equivalent impedance;

[0026] The high-voltage side of the excitation transformer is connected to the low-voltage side of the main transformer through a low-voltage switch, and the low-voltage side of the excitation transformer is connected to the excitation power unit of the pumped storage unit;

[0027] The excitation control system is communicatively connected with the monitoring system of the pumped storage unit.

[0028] Preferably, the method obtains the excitation control performance index of the pumped storage unit by performing a no-load step test on a single-machine infinite power system simulation model, and the specific steps are:

[0029] Disconnect the low-voltage switch, the main voltage control loop participates in the control and the system voltage control loop does not participate in the control;

[0030] Setting the speed of the pumped storage unit to the rated speed and the terminal voltage reference value of the pumped storage unit to the first preset value;

[0031] A PID controller is used to control the excitation control system to output an excitation control voltage so that the terminal voltage of the pumped storage unit reaches a first preset value;

[0032] Setting the step amount of the terminal voltage reference value of the pumped storage unit to a preset step amount, and recording the waveform of the terminal voltage of the pumped storage unit in response to the preset step amount;

[0033] An excitation control performance index of the pumped storage unit is obtained according to the waveform.

[0034] Preferably, the proportional gain, integral gain, and differential gain of the PID controller are optimized based on the excitation control performance index, and the specific steps are as follows:

[0035] The excitation control performance indicators include rise time, number of terminal voltage oscillations, adjustment time and overshoot;

[0036] Adjusting the proportional gain so that the rise time meets the first preset interval and the number of terminal voltage oscillations meets the second preset interval;

[0037] If the time for the terminal voltage of the pumped storage unit to reach stability in the no-load step test is greater than the first preset time or the adjustment time is greater than the second preset time, adjusting the integral gain;

[0038] Adjusting the differential gain so that the overshoot value satisfies the fourth preset range and the number of terminal voltage oscillations satisfies the second preset range;

[0039] The optimized proportional gain, integral gain and differential gain are obtained.

[0040] On the other hand, the present invention also provides a pumped storage unit excitation control device with fast response, comprising:

[0041] System voltage control loop gain module: determines the high-voltage side voltage droop slope of the main transformer according to the reactive support demand of the pumped storage power plant in the power grid, and determines the system voltage control loop gain based on the high-voltage side voltage droop slope;

[0042] Dual-loop pumped storage unit excitation control module: Constructs a dual-loop excitation control system. The dual-loop structure is specifically a parallel structure including a main voltage control loop and a system voltage control loop, wherein:

[0043] The system voltage control loop is composed of a system voltage control loop gain and a two-stage lead-lag correction link connected in series. The input end receives the deviation signal of the reference value and the measured value of the high-voltage side voltage of the main transformer, amplifies it through the system voltage control loop gain, and then corrects it through the two-stage lead-lag link and limits it as the high-voltage side voltage deviation control signal.

[0044] The main voltage control loop is composed of a parallel PID controller, the input end of which receives the deviation signal of the reference value and the measured value of the pumped storage unit terminal voltage, and superimposes it with the high-voltage side voltage deviation control signal. After superposition, it is input into the parallel PID controller for correction calculation and outputs the excitation control signal;

[0045] The excitation control signal is input into the excitation power unit of the pumped storage unit for power amplification, and the excitation control voltage is obtained to control the pumped storage unit.

[0046] Preferably, the excitation control voltage is expressed as:

[0047]

[0048] Where U fd Indicates the excitation control voltage, U g Represents the measured value of the terminal voltage of the pumped storage unit, r g Indicates the reference value of the terminal voltage of the pumped storage unit, r h Indicates the reference value of the high voltage side voltage of the main transformer, U H Indicates the measured value of the high voltage side voltage of the main transformer, K H represents the system voltage control loop gain, s represents a complex variable, T1, T2, T3, T4 represent the time constants of the two-stage lead-lag correction link, K p Represents the proportional gain, K i Indicates the integral gain, K d represents the differential gain, T A Indicates the delay time of the power amplifier link, K A Indicates the gain of the power amplifier link.

[0049] The present invention has the following beneficial effects:

[0050] 1. The present invention constructs a parallel structure excitation control system based on a main voltage control loop and a system voltage control loop. The main voltage control loop adopts a parallel PID controller structure, and the system voltage control loop adopts a series two-stage lead-lag correction link structure. It can quickly detect and respond to fluctuations in grid voltage, achieve precise control of the excitation of the pumped storage unit, and maintain the stability of the grid voltage.

[0051] 2. The present invention constructs a single-machine infinite power system simulation model, performs no-load step tests and load step tests on the excitation control system, obtains excitation control performance indicators, and optimizes the proportional gain, integral gain, and differential gain of the PID controller based on these indicators, thereby further improving the dynamic performance of the excitation control system.

[0052] 3. This invention significantly enhances the reactive power regulation capability of pumped-storage units. When the equivalent infinite grid voltage drops, the reactive power output of a pumped-storage unit using this invention is approximately twice that of a conventional excitation unit. This rapidly provides a large amount of reactive power, supporting the system voltage and maintaining reactive power balance in the power system, thus reducing equipment failures and power outages caused by voltage anomalies. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is a block diagram of the excitation control method of the present invention.

[0054] Figure 2 This is a voltage droop characteristic curve of the high-voltage side of the main transformer of the present invention.

[0055] Figure 3 This is a structural diagram of the single-machine infinite power system simulation model of the present invention.

[0056] Figure 4 This is a comparison curve diagram of the reactive power effect of the present invention.

[0057] Figure 5 This is a voltage curve diagram of the high-voltage side of the main transformer after the infinite grid voltage drops in the present invention.

[0058] Figure 6 This is a structural diagram of the application scenario of the device of the present invention. DETAILED DESCRIPTION

[0059] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0060] It should be understood that the step numbers used herein are only for convenience of description and are not intended to limit the order in which the steps are to be executed.

[0061] It should be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an" and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0062] The terms “include” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0063] The term "and / or" refers to and includes any and all possible combinations of one or more of the associated listed items.

[0064] Example 1:

[0065] See also Figure 1 This embodiment provides a method for controlling the excitation of a pumped storage unit with rapid response, comprising the following steps:

[0066] Determine the voltage droop slope on the high-voltage side of the main transformer according to the reactive support demand of the pumped-storage power plant in the power grid, and determine the system voltage control loop gain based on the voltage droop slope on the high-voltage side;

[0067] Construct an excitation control system with a dual-loop structure. The dual-loop structure is specifically a parallel structure including a main voltage control loop and a system voltage control loop, wherein:

[0068] The system voltage control loop is composed of a system voltage control loop gain and a two-stage lead-lag correction link connected in series. The input end receives the deviation signal of the reference value and the measured value of the high-voltage side voltage of the main transformer, amplifies it through the system voltage control loop gain, and then corrects it through the two-stage lead-lag link and limits it as the high-voltage side voltage deviation control signal.

[0069] The main voltage control loop is composed of a parallel PID controller, the input end of which receives the deviation signal of the reference value and the measured value of the pumped storage unit terminal voltage, and superimposes it with the high-voltage side voltage deviation control signal. After superposition, it is input into the parallel PID controller for correction calculation and outputs the excitation control signal;

[0070] The excitation control signal is input into the excitation power unit of the pumped storage unit for power amplification, and the excitation control voltage is obtained to control the pumped storage unit.

[0071] Preferably, the excitation control voltage is expressed as:

[0072]

[0073] Where U fd Indicates the excitation control voltage, U g Represents the measured value of the terminal voltage of the pumped storage unit, r g Indicates the reference value of the terminal voltage of the pumped storage unit, r h Indicates the reference value of the high voltage side voltage of the main transformer, U H Indicates the measured value of the high voltage side voltage of the main transformer, K H represents the system voltage control loop gain, s represents a complex variable, T1, T2, T3, T4 represent the time constants of the two-stage lead-lag correction link, K pRepresents the proportional gain, K i Indicates the integral gain, K d represents the differential gain, T A Indicates the delay time of the power amplifier link, K A Indicates the gain of the power amplifier link, represents a parallel PID controller, Represents a two-stage lead-lag correction link, It represents the first-level lead-lag correction link. It represents the second-level lead-lag correction link. Represents the mathematical model of the excitation power unit.

[0074] The parallel PID controller means that the proportional, differential and integral links are calculated independently and in parallel, and the outputs are added.

[0075] Excitation control signal U c It can be expressed as:

[0076]

[0077] The input of the PID control algorithm in steady state is U uerr , expressed as:

[0078] U uerr =(r h -U H )K H +(r g -U g ) (1)

[0079] After normalization, the high-voltage side voltage of the main transformer and the terminal voltage of the pumped storage unit have the following equation relationship, which can be expressed as:

[0080] U H =(U g -X t I q ) (2)

[0081] Due to the effect of the integral gain in the PID controller at steady state, the final steady state input deviation U uerr To approach 0, that is:

[0082] U uerr =0 (3)

[0083] Substituting formula (3) into formula (1), we get:

[0084] 0=(r h -U H )K H +(r g -U g ) (4)

[0085] By combining equations (2) and (4), we can obtain the steady-state representation of the high-voltage side voltage of the main transformer and the steady-state representation of the terminal voltage of the pumped storage unit.

[0086] The measured value reaches a steady state and does not change within a period of time, which is the steady-state value.

[0087] Preferably, the steady-state value of the high-voltage side voltage of the main transformer is expressed as follows:

[0088]

[0089] Where, X t Indicates the per-unit short-circuit impedance of the main transformer, I q It represents the per unit value of the reactive component of the terminal current of the pumped storage unit.

[0090] Preferably, the steady-state value of the terminal voltage of the pumped storage unit is expressed as follows:

[0091]

[0092] Where, X t Indicates the per-unit short-circuit impedance of the main transformer, I q It represents the per unit value of the reactive component of the terminal current of the pumped storage unit.

[0093] The per-unit value of the short-circuit impedance of the main transformer is obtained by dividing the reference value of capacity by the reference value of voltage. The per-unit value of the reactive component of the terminal current of the pumped storage unit is obtained by dividing the square of the reference value of voltage by the reference value of capacity. The reference value of voltage is the rated voltage.

[0094] Per unit value means the measured value / reference value;

[0095] Preferably, the system voltage control loop gain is expressed as:

[0096]

[0097] Where D represents the preset voltage droop slope of the high-voltage side of the main transformer, X t Indicates the per-unit short-circuit impedance of the main transformer.

[0098] See also Figure 2 , K H The smaller the voltage drop, the greater the K H The larger the voltage drop, the smaller the voltage drop. The voltage droop slope D on the high-voltage side of the main transformer can be set at 5%-10% based on the voltage support role of the pumped storage power plant in the power grid. The smaller the voltage droop slope D on the high-voltage side of the main transformer, the stronger the power plant's dynamic reactive power support role in the system.

[0099] In at least one embodiment, X t Take the value as 0.2, and D as 5%-10%, then we can get K H The value is 1-3.

[0100] See also Figure 4 , which simulates a 10% drop in the equivalent infinite grid voltage. The reactive power output curves of the pumped storage unit under different excitation control methods. Before the equivalent infinite grid voltage drops, the reactive power outputs of the two excitation control methods are almost the same. After the equivalent infinite grid voltage drops by 10%, the reactive power output of the pumped storage unit controlled by the control method proposed in the present invention is about twice that of the traditional excitation output reactive power.

[0101] See also Figure 5 , which is an equivalent infinite grid voltage drop of 10%. The high-voltage side voltage curves of the main transformer of the pumped storage unit under different excitation control methods. Before the equivalent infinite grid voltage drops, the high-voltage side voltage of the main transformer is almost the same. After the system voltage drops by 10%, the pumped storage unit controlled by the control method proposed in the present invention can maintain the high-voltage side voltage of the main transformer at a relatively high voltage level compared with the traditional excitation control method.

[0102] See also Figure 3 , preferably, the method further comprises constructing a single-machine infinite power system simulation model, including a pumped storage unit, an excitation control system, a high-voltage switch, a low-voltage switch, a main transformer, a transmission line, an excitation transformer, a system equivalent impedance, and a system equivalent infinite power supply;

[0103] The pumped storage unit is connected to the low-voltage side of the main transformer through a low-voltage switch, the high-voltage side of the main transformer is connected to one end of the transmission line through a high-voltage switch, and the other end of the transmission line is connected to the system equivalent infinite power supply through the system equivalent impedance;

[0104] The high-voltage side of the excitation transformer is connected to the low-voltage side of the main transformer through a low-voltage switch, and the low-voltage side of the excitation transformer is connected to the excitation power unit of the pumped storage unit;

[0105] The excitation control system is communicatively connected with the monitoring system of the pumped storage unit.

[0106] The low voltage switch is a GCB switch, i.e. a gas circuit breaker, and the high voltage switch is a CB switch, i.e. a circuit breaker. Figure 3 shown.

[0107] Preferably, the method obtains the excitation control performance index of the pumped storage unit by performing a no-load step test on a single-machine infinite power system simulation model, and the specific steps are:

[0108] Disconnect the low-voltage switch, the main voltage control loop participates in the control and the system voltage control loop does not participate in the control;

[0109] Setting the speed of the pumped storage unit to the rated speed and the terminal voltage reference value of the pumped storage unit to the first preset value;

[0110] A PID controller is used to control the excitation control system to output an excitation control voltage so that the terminal voltage of the pumped storage unit reaches a first preset value;

[0111] Setting the step amount of the terminal voltage reference value of the pumped storage unit to a preset step amount, and recording the waveform of the terminal voltage of the pumped storage unit in response to the preset step amount;

[0112] An excitation control performance index of the pumped storage unit is obtained according to the waveform.

[0113] In at least one embodiment, the first preset value is 95% of the rated value, and the preset step value can be within a range of 1%-5%, and in this embodiment, it is 4%.

[0114] Preferably, the proportional gain, integral gain, and differential gain of the PID controller are optimized based on the excitation control performance index, and the specific steps are as follows:

[0115] The excitation control performance indicators include rise time, number of terminal voltage oscillations, adjustment time and overshoot;

[0116] Adjusting the proportional gain so that the rise time meets the first preset interval and the number of terminal voltage oscillations meets the second preset interval;

[0117] If the time for the terminal voltage of the pumped storage unit to reach stability in the no-load step test is greater than the first preset time or the adjustment time is greater than the second preset time, adjusting the integral gain;

[0118] Adjusting the differential gain so that the overshoot value satisfies the fourth preset range and the number of terminal voltage oscillations satisfies the second preset range;

[0119] The optimized proportional gain, integral gain and differential gain are obtained.

[0120] In at least one embodiment, the optimization process is specifically as follows:

[0121] First, increase the proportional gain K p Make the rise time reach the first preset interval (no more than 0.5 seconds), and on the basis of ensuring that the rise time remains in the first preset interval, reduce the proportional gain K p The number of terminal voltage oscillations is made to meet a second preset range (no more than 3 times);

[0122] Then, if the time for the terminal voltage of the pumped storage unit to reach stability in the no-load step test is greater than the first preset time (8 seconds) or the adjustment time is greater than the second preset time (2 seconds), the integral gain is increased;

[0123] Finally, increase the differential gain K d The overshoot amount is made to meet the fourth preset range (the overshoot amount is not greater than 30%) and the number of oscillations of the terminal voltage is made to meet the second preset range.

[0124] Preferably, the method further comprises optimizing the time constant of the two-stage lead-lag correction link, specifically the following steps:

[0125] Close the low-voltage switch, and the main voltage control loop and the system voltage control loop participate in the control. The main voltage control loop uses the optimized proportional gain, integral gain, and differential gain;

[0126] The active power output of the pumped storage unit is set to the rated active power, and the reference value of the high-voltage side voltage of the main transformer is set to 95%;

[0127] Setting the step value of the voltage reference value on the high-voltage side of the main transformer to 1%-2%, and recording the waveform of the active power of the pumped storage unit in response to the preset step value;

[0128] A hysteresis performance index of the pumped storage unit is obtained according to the waveform.

[0129] Based on the lag performance index, the time constants T1, T2, T3, and T4 of the two-stage lead-lag correction link are optimized. The specific steps are as follows:

[0130] The excitation control performance index includes the damping ratio of active power;

[0131] Adjust T1, T2, T3, and T4 so that the power and damping ratio meet the requirements of on-site technicians;

[0132] The optimized time constants T1, T2, T3, and T4 of the two-stage lead-lag correction link are obtained.

[0133] Example 2:

[0134] Lieutenant General Figure 6 This embodiment also provides a pumped storage unit excitation control device with fast response, including a CPU, ADC sampling, program memory, communication module, pulse generation, and pulse amplification:

[0135] The output end of the ADC sampling is connected to the input end of the CPU, the output end of the program memory is connected to the input end of the CPU, the output end of the CPU is respectively connected to the input end of the communication module and the input end of the pulse generation, and the output end of the pulse generation is connected to the input end of the pulse amplification;

[0136] The CPU includes a system voltage control loop gain module and a double-loop structure pumped storage unit excitation control module;

[0137] System voltage control loop gain module: determines the high-voltage side voltage droop slope of the main transformer according to the reactive support demand of the pumped storage power plant in the power grid, and determines the system voltage control loop gain based on the high-voltage side voltage droop slope;

[0138] Dual-loop pumped storage unit excitation control module: Constructs a dual-loop excitation control system. The dual-loop structure is specifically a parallel structure including a main voltage control loop and a system voltage control loop, wherein:

[0139] The system voltage control loop is composed of a system voltage control loop gain and a two-stage lead-lag correction link connected in series. The input end receives the deviation signal of the reference value and the measured value of the high-voltage side voltage of the main transformer, amplifies it through the system voltage control loop gain, and then corrects it through the two-stage lead-lag link and limits it as the high-voltage side voltage deviation control signal.

[0140] The main voltage control loop is composed of a parallel PID controller, the input end of which receives the deviation signal of the reference value and the measured value of the pumped storage unit terminal voltage, and superimposes it with the high-voltage side voltage deviation control signal. After superposition, it is input into the parallel PID controller for correction calculation and outputs the excitation control signal;

[0141] The excitation control signal is input into the excitation power unit of the pumped storage unit for power amplification, and the excitation control voltage is obtained to control the pumped storage unit.

[0142] The signals input to the excitation control device include the main transformer high-voltage side voltage, generator-end voltage, generator-end current, excitation voltage, and synchronization signal. The signals output by the excitation control device include the excitation voltage signal and external communication signals. The main transformer high-voltage side voltage, generator-end voltage, and generator-end current are used to calculate the excitation voltage signal output to the rectifier bridge. The synchronization signal is the power supply voltage signal of the rectifier bridge, which is used to synchronize with the excitation voltage signal. The external communication signals input to the excitation control device include the generator-end voltage reference value and the main transformer high-voltage side voltage reference value. The generator-end voltage reference value and the main transformer high-voltage side voltage reference value are manually set based on the operating conditions of the power system. The external communication signals output by the excitation control device include the current system's main transformer high-voltage side voltage, generator-end voltage, generator-end current, and excitation voltage, which are sent to the monitoring system.

[0143] Preferably, the excitation control voltage is expressed as:

[0144]

[0145] Where U fd Indicates the excitation control voltage, U g Represents the measured value of the terminal voltage of the pumped storage unit, r g Indicates the reference value of the terminal voltage of the pumped storage unit, rh Indicates the reference value of the high voltage side voltage of the main transformer, U H Indicates the measured value of the high voltage side voltage of the main transformer, K H represents the system voltage control loop gain, s represents a complex variable, T1, T2, T3, T4 represent the time constants of the two-stage lead-lag correction link, K p Represents the proportional gain, K i Indicates the integral gain, K d represents the differential gain, T A Indicates the delay time of the power amplifier link, K A Indicates the gain of the power amplifier link.

[0146] This device is used to implement the method described in Example 1 and will not be described in detail here.

[0147] In the embodiments of the present application, "at least one" refers to one or more, and "more" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can represent: a, b, c, a and b, a and c, b and c or a and b and c, where a, b, c can be single or multiple.

[0148] Those skilled in the art will appreciate that the various units and algorithm steps described in the embodiments disclosed herein can be implemented using a combination of electronic hardware, computer software, and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0149] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0150] In the several embodiments provided in this application, if any function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of this application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory; hereinafter referred to as: ROM), random access memory (Random Access Memory; hereinafter referred to as: RAM), magnetic disk or optical disk, and other media that can store program code.

[0151] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention's description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for controlling the excitation of a pumped storage unit with rapid response, characterized in that: The following steps are involved: Determine the voltage droop slope on the high-voltage side of the main transformer according to the reactive support demand of the pumped-storage power plant in the power grid, and determine the system voltage control loop gain based on the voltage droop slope on the high-voltage side; Construct an excitation control system with a dual-loop structure. The dual-loop structure is specifically a parallel structure including a main voltage control loop and a system voltage control loop, wherein: The system voltage control loop is composed of a system voltage control loop gain and a two-stage lead-lag correction link connected in series. The input end receives the deviation signal of the reference value and the measured value of the high-voltage side voltage of the main transformer, amplifies it through the system voltage control loop gain, and then corrects it through the two-stage lead-lag link and limits it as the high-voltage side voltage deviation control signal. The main voltage control loop is composed of a parallel PID controller, the input end of which receives the deviation signal of the reference value and the measured value of the pumped storage unit terminal voltage, and superimposes it with the high-voltage side voltage deviation control signal. After superposition, it is input into the parallel PID controller for correction calculation and outputs the excitation control signal; The excitation control signal is input into the excitation power unit of the pumped storage unit for power amplification, and the excitation control voltage is obtained to control the pumped storage unit.

2. The method for controlling the excitation of a pumped storage unit with rapid response according to claim 1, characterized in that: The excitation control voltage is expressed as follows: Where U fd Indicates the excitation control voltage, U g Represents the measured value of the terminal voltage of the pumped storage unit, r g Indicates the reference value of the terminal voltage of the pumped storage unit, r h Indicates the reference value of the high voltage side voltage of the main transformer, U H Indicates the measured value of the high voltage side voltage of the main transformer, K H represents the system voltage control loop gain, s represents a complex variable, T1, T2, T3, T4 represent the time constants of the two-stage lead-lag correction link, K p Represents the proportional gain, K i Indicates the integral gain, K d represents the differential gain, T A Indicates the delay time of the power amplifier link, K A Indicates the gain of the power amplifier link.

3. The method for controlling the excitation of a pumped storage unit with rapid response according to claim 2, characterized in that: The steady-state value of the high-voltage side voltage of the main transformer is expressed as follows: Where, X t Indicates the per-unit short-circuit impedance of the main transformer, I q It represents the per unit value of the reactive component of the terminal current of the pumped storage unit.

4. The method for controlling the excitation of a pumped storage unit with rapid response according to claim 2, characterized in that: The steady-state value of the terminal voltage of the pumped storage unit is expressed as follows: Where, X t Indicates the per-unit short-circuit impedance of the main transformer, I q It represents the per unit value of the reactive component of the terminal current of the pumped storage unit.

5. The method for controlling the excitation of a pumped storage unit with rapid response according to claim 2, characterized in that: The system voltage control loop gain is expressed as: Where D represents the preset voltage droop slope of the high-voltage side of the main transformer, X t Indicates the per-unit short-circuit impedance of the main transformer.

6. The method for controlling the excitation of a pumped storage unit with rapid response according to claim 1, characterized in that: The method further includes constructing a single-machine infinite power system simulation model, including a pumped storage unit, an excitation control system, a high-voltage switch, a low-voltage switch, a main transformer, a transmission line, an excitation transformer, a system equivalent impedance, and a system equivalent infinite power supply; The pumped storage unit is connected to the low-voltage side of the main transformer through a low-voltage switch, the high-voltage side of the main transformer is connected to one end of the transmission line through a high-voltage switch, and the other end of the transmission line is connected to the system equivalent infinite power supply through the system equivalent impedance; The high-voltage side of the excitation transformer is connected to the low-voltage side of the main transformer through a low-voltage switch, and the low-voltage side of the excitation transformer is connected to the excitation power unit of the pumped storage unit; The excitation control system is communicatively connected with the monitoring system of the pumped storage unit.

7. The method for controlling the excitation of a pumped storage unit with rapid response according to claim 6, characterized in that: The method obtains the excitation control performance index of the pumped storage unit by performing a no-load step test on a single-machine infinite power system simulation model. The specific steps are: Disconnect the low-voltage switch, the main voltage control loop participates in the control and the system voltage control loop does not participate in the control; Setting the speed of the pumped storage unit to the rated speed and the terminal voltage reference value of the pumped storage unit to the first preset value; The main voltage control loop is used to control the excitation control system to output the excitation control voltage so that the terminal voltage of the pumped storage unit reaches a first preset value; Setting the step amount of the terminal voltage reference value of the pumped storage unit to a preset step amount, and recording the waveform of the terminal voltage of the pumped storage unit in response to the preset step amount; An excitation control performance index of the pumped storage unit is obtained according to the waveform.

8. The method for controlling the excitation of a pumped storage unit with rapid response according to claim 7, characterized in that: Based on the excitation control performance index, the proportional gain, integral gain, and differential gain of the PID controller are optimized. The specific steps are as follows: The excitation control performance indicators include rise time, number of terminal voltage oscillations, adjustment time and overshoot; Adjusting the proportional gain so that the rise time meets the first preset interval and the number of terminal voltage oscillations meets the second preset interval; If the time for the terminal voltage of the pumped storage unit to reach stability in the no-load step test is greater than the first preset time or the adjustment time is greater than the second preset time, adjusting the integral gain; Adjusting the differential gain so that the overshoot value satisfies the fourth preset range and the number of terminal voltage oscillations satisfies the second preset range; The optimized proportional gain, integral gain and differential gain are obtained.

9. A pumped storage unit excitation control device with fast response, characterized in that: include: System voltage control loop gain module: determines the high-voltage side voltage droop slope of the main transformer according to the reactive support demand of the pumped storage power plant in the power grid, and determines the system voltage control loop gain based on the high-voltage side voltage droop slope; Dual-loop pumped storage unit excitation control module: Constructs a dual-loop excitation control system. The dual-loop structure is specifically a parallel structure including a main voltage control loop and a system voltage control loop, wherein: The system voltage control loop is composed of a system voltage control loop gain and a two-stage lead-lag correction link connected in series. The input end receives the deviation signal of the reference value and the measured value of the high-voltage side voltage of the main transformer, amplifies it through the system voltage control loop gain, and then corrects it through the two-stage lead-lag link and limits it as the high-voltage side voltage deviation control signal. The main voltage control loop is composed of a parallel PID controller, the input end of which receives the deviation signal of the reference value and the measured value of the pumped storage unit terminal voltage, and superimposes it with the high-voltage side voltage deviation control signal. After superposition, it is input into the parallel PID controller for correction calculation and outputs the excitation control signal; The excitation control signal is input into the excitation power unit of the pumped storage unit for power amplification, and the excitation control voltage is obtained to control the pumped storage unit.

10. The excitation control device for a pumped storage unit with rapid response according to claim 9, characterized in that: The excitation control voltage is expressed as follows: Where U fd Indicates the excitation control voltage, U g Represents the measured value of the terminal voltage of the pumped storage unit, r g Indicates the reference value of the terminal voltage of the pumped storage unit, r h Indicates the reference value of the high voltage side voltage of the main transformer, U H Indicates the measured value of the high voltage side voltage of the main transformer, K H represents the system voltage control loop gain, s represents a complex variable, T1, T2, T3, T4 represent the time constants of the two-stage lead-lag correction link, K p Represents the proportional gain, K i Indicates the integral gain, K d represents the differential gain, T A Indicates the delay time of the power amplifier link, K A Indicates the gain of the power amplifier link.

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