Receiving end power grid reactive power compensation control system and method and computer storage medium

Abstract

The application discloses a reactive power compensation control system of a receiving end power grid, comprising a measurement sampling unit, a superconducting phase modifier, a static synchronous compensator and a cooperative control module; in the case that the voltage of a grid-connected point bus is less than the lower limit of a preset dead zone, the reactive power compensation control system is controlled to enter a fault support mode, in the fault support mode, the reactive power compensation control system takes the superconducting phase modifier as a main reactive power source and cooperates with the static synchronous compensator to provide dynamic reactive power support, so as to reduce voltage drop and promote voltage recovery; in the case that the voltage of the grid-connected point bus is greater than the upper limit of the preset dead zone, the reactive power compensation control system is controlled to enter a recovery inhibition mode, in the recovery inhibition mode, the reactive power compensation control system takes the static synchronous compensator as a main part to execute an absorbed reactive power instruction to inhibit voltage overshoot. The system gives consideration to voltage drop support and voltage overshoot inhibition through the segmented coordination of the superconducting phase modifier and the static synchronous compensator.

Description

Technical Field

[0001] This application relates to the field of reactive power compensation technology in power systems, and in particular to a reactive power compensation control system, method, and computer storage medium for a receiving-end power grid. Background Technology

[0002] When a short-circuit fault occurs in the power grid, the voltage exhibits a two-stage characteristic: a deep voltage drop at the moment of the fault and voltage overshoot oscillation after the fault is cleared. A single reactive power compensation device cannot simultaneously handle large-capacity transient reactive power injection and millisecond-level rapid reactive power absorption. Superconducting synchronous condensers have high efficiency in regulation, fast response speed, and high mechanical inertia; static synchronous compensators have the characteristics of fast response and good economy.

[0003] Existing technologies have proposed strategies such as coordinating synchronous condensers and SVCs to suppress transient overvoltages. However, most of the synchronous condensers in the existing technologies are conventional synchronous condensers, whose reactive power support capability is limited by excitation losses and adjustment range. Their dynamic reactive power margin is insufficient at the moment of fault, and they lack clear master-slave switching and priority constraints for the voltage recovery stage after fault clearance. This can easily lead to reactive power superposition or overcompensation, resulting in unstable overshoot suppression effect. Summary of the Invention

[0004] This application provides a reactive power compensation control system, method, and computer storage medium for a receiving-end power grid. The system achieves both voltage drop support and voltage overshoot suppression through segmented coordination between a superconducting synchronous condenser and a static synchronous compensator.

[0005] Firstly, this application provides a reactive power compensation control system for a receiving-end power grid, comprising: The measurement sampling unit is used to sample the voltage of the bus at the grid connection point; The superconducting camera is electrically connected to the grid connection point bus. The static synchronous compensator is electrically connected to the grid connection point bus. The collaborative control module is configured to adjust based on the bus voltage at the grid connection point. When the voltage at the grid connection point bus is less than the lower limit of the preset dead zone voltage, the reactive power compensation control system enters the fault support mode. In the fault support mode, the reactive power compensation control system uses the superconducting synchronous condenser as the main reactive power source and works with the static synchronous compensator to provide dynamic reactive power support in order to reduce voltage drop and promote voltage recovery. When the voltage at the grid connection point bus exceeds the upper limit of the preset dead zone voltage, the reactive power compensation control system enters the recovery suppression mode. In the recovery suppression mode, the reactive power compensation control system uses the static synchronous compensator as the main controller to execute the reactive power absorption command to suppress voltage overshoot.

[0006] In one embodiment, when the bus voltage at the grid connection point is within a preset dead zone, the reactive power compensation control system is controlled to enter a steady-state mode. In the steady-state mode, the reactive power compensation control system uses a static synchronous compensator as the main reactive power regulation device. Furthermore, the superconducting camera enables a reactive power output limiting strategy in steady-state mode, limiting the reactive power output of the superconducting camera to a preset range.

[0007] In one embodiment, the cooperative control module employs a combination of Q-V droop control and voltage closed-loop control to generate reactive power regulation commands for the static synchronous compensator according to the following steps: The collaborative control module acquires the measured value of the reactive power currently output or absorbed by the static synchronous compensator, as well as the per-unit value of the bus voltage at the grid connection point; The collaborative control module normalizes the reactive power measurement value according to the rated capacity of the static synchronous compensator to obtain the reactive power per-unit value. The collaborative control module takes voltage values ​​according to the preset minimum limit of the per-unit voltage of the grid connection point bus. Based on the voltage and reactive power per-unit values, it calculates the droop compensation amount according to the preset droop coefficient. The collaborative control module superimposes the per-unit value of the bus voltage at the grid connection point with the droop compensation amount to obtain the voltage control amount; The collaborative control module filters and shapes the voltage control quantity to obtain a smooth voltage signal; The collaborative control module compares the smoothed voltage signal with the preset reference voltage to obtain the voltage error. After the voltage error is compensated for lead-lag, it is input into the PI regulator to generate the reactive power regulation command of the static synchronous compensator. Among them, the droop coefficient of the static synchronous compensator, the filtering time constant for filtering and shaping the voltage control quantity, and the upper limit of the reactive power change rate of the static synchronous compensator are adjusted according to the mode of the reactive power compensation control system.

[0008] In one embodiment, under fault-support mode, the reactive power compensation control system uses a superconducting synchronous condenser as the primary reactive power source, working in conjunction with a static synchronous compensator to provide dynamic reactive power support, including: The reactive power limiting parameter of the superconducting camera is adjusted to the first limit, which is greater than the second limit. The second limit is the reactive power limiting parameter of the superconducting camera in steady-state mode. Furthermore, the upper limit of the excitation current change rate of the superconducting camera is set to be positively correlated with the superconductivity margin index. Furthermore, the upper limit of the reactive power change rate and the droop coefficient of the static synchronous compensator are set to be higher than the corresponding parameters in the steady-state mode, and the filter time constant is set to be lower than the filter time constant in the steady-state mode.

[0009] In one embodiment, in recovery suppression mode, the reactive power compensation control system, primarily driven by a static synchronous compensator, executes reactive power absorption commands to suppress voltage overshoot, including: The reactive power limiting parameter of the superconducting camera is adjusted to the third limit, which is less than the first limit and greater than the second limit. Furthermore, the upper limit of the excitation current change rate of the superconducting camera is set between the upper limit of the excitation current change rate in steady-state mode and fault support mode. The upper limit of the excitation current change rate is set to an asymmetric constraint, with a larger upper limit of the excitation current change rate in the de-excitation direction and a smaller upper limit of the excitation current change rate in the up-excitation direction. Furthermore, the droop coefficient, filter time constant, and upper limit of reactive power change rate of the static synchronous compensator are set to be between the corresponding parameters of steady-state mode and fault support mode. The upper limit of reactive power change rate is set as an asymmetric constraint, with a larger upper limit of reactive power change rate in the reactive power absorption direction and a smaller upper limit of reactive power change rate in the reactive power output direction.

[0010] In one embodiment, the upper limit of the excitation current change rate in the de-excitation direction is positively correlated with the degree of overvoltage and negatively correlated with the superconductivity margin index.

[0011] In one embodiment, the reactive power compensation control system further includes a superconductivity margin monitoring module for monitoring the superconductivity margin index generated by the superconducting camera. The smaller the superconductivity margin index, the closer the superconducting camera is to losing quench. The superconductivity margin monitoring module monitors the winding temperature and magnetic field strength of the excitation circuit of the superconducting phase converter online, dynamically calculates the upper limit of the excitation current, and generates a superconductivity margin index based on the upper limit of the excitation current and the critical quench current. The superconductivity margin index is negatively correlated with the upper limit of the excitation current.

[0012] Secondly, this application also provides a reactive power compensation control method, which applies the reactive power compensation control system of the first aspect, and the reactive power compensation control method includes: The system collects the voltage of the grid connection point bus. When the voltage of the grid connection point bus is less than the lower limit of the preset dead zone, the reactive power compensation control system is controlled to enter the fault support mode. When the voltage of the grid connection point bus is greater than the upper limit of the preset dead zone, the reactive power compensation control system is controlled to enter the recovery suppression mode. When the voltage of the grid connection point bus is within the preset dead zone, the reactive power compensation control system is controlled to enter the steady-state mode.

[0013] Thirdly, this application also provides a computer storage medium storing a processing program, which executes the reactive power compensation control method as described in the second aspect when the processing program is run.

[0014] The aforementioned reactive power compensation control system includes a measurement and sampling unit, a superconducting phase-shifting camera, a static synchronous compensator (Synchronous Compensator), and a collaborative control module. The measurement and sampling unit samples the voltage of the grid connection point bus; the superconducting phase-shifting camera and the Synchronous Compensator are connected in parallel to the grid connection point bus. The collaborative control module switches operating modes based on the relationship between the grid connection point voltage and a preset dead zone: when the voltage is below the lower limit of the dead zone, it enters fault support mode, where the superconducting phase-shifting camera, in coordination with the Synchronous Compensator, provides dynamic reactive power support, reducing voltage dips and promoting recovery; when the voltage is above the upper limit of the dead zone, it enters recovery suppression mode, where the Synchronous Compensator, in coordination with the Synchronous Compensator, executes reactive power absorption commands to suppress voltage overshoot. Through segmented coordinated control of the superconducting phase-shifting camera and the Synchronous Compensator, the system leverages the large capacity of the superconducting phase-shifting camera to suppress voltage dips in fault support mode, and utilizes the fast response characteristics of the Synchronous Compensator to suppress voltage overshoot in recovery suppression mode, achieving dynamic reactive power matching and stable voltage support during fault processes. Attached Figure Description

[0015] Figure 1 This is a structural diagram of the reactive power compensation control system of the receiving-end power grid in one embodiment; Figure 2 This is a comparison diagram of the voltage support of a superconducting camera modulator and a conventional camera modulator in one embodiment; Figure 3 This is a diagram of the excitation circuit for a superconducting camera in one embodiment; Figure 4 Here is a circuit diagram of a static synchronous compensator in one embodiment; Figure 5 This is a structural diagram of the reactive power compensation control system of the receiving-end power grid in another embodiment; Figure 6 This is a flowchart illustrating the generation of reactive power adjustment commands for a static synchronous compensator in one embodiment. Detailed Implementation

[0016] The present application will be described in detail below with reference to the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present application. Any structural, methodological, or functional modifications made by those skilled in the art based on these embodiments are included within the protection scope of the present application.

[0017] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0018] In one embodiment, such as Figure 1 As shown, this application provides a reactive power compensation control system for a receiving-end power grid, the reactive power compensation control system comprising: The measurement sampling unit is used to sample the voltage of the bus at the grid connection point; The superconducting camera is electrically connected to the grid connection point bus. The static synchronous compensator is electrically connected to the grid connection point bus. The collaborative control module is configured to control the reactive power compensation control system to enter the fault support mode when the voltage of the grid connection point bus is less than the lower limit of the preset dead zone. In the fault support mode, the reactive power compensation control system uses the superconducting synchronous condenser as the main reactive power source and works with the static synchronous compensator to provide dynamic reactive power support in order to reduce voltage drop and promote voltage recovery. When the voltage at the grid connection point bus exceeds the upper limit of the preset dead zone voltage, the reactive power compensation control system enters the recovery suppression mode. In the recovery suppression mode, the reactive power compensation control system uses the static synchronous compensator as the main controller to execute the reactive power absorption command to suppress voltage overshoot.

[0019] Specifically, the measurement and sampling unit collects the voltage value of the grid connection point bus in real time and sends the collected voltage value to the collaborative control module.

[0020] Superconducting synchronous condensers can be connected in parallel to the grid connection point bus via a step-up transformer. The superconducting synchronous condenser also includes an excitation system, which employs a four-phase interleaved parallel DC / DC converter structure composed of fully controlled silicon carbide devices. Because superconducting excitation losses are close to zero, its energy consumption is significantly lower than that of traditional synchronous condensers, while maintaining high efficiency.

[0021] It should be noted that the reactive power change of a traditional synchronous condenser after a fault... for: ; in, This is the subtransient electromotive force of the q-axis when a traditional synchronous condenser fails, and the subtransient electromotive force cannot change abruptly. The d-axis subtransient reactance; This refers to the grid voltage. This represents the change in terminal voltage after a fault.

[0022] The complex frequency domain expression for the stator current change of a traditional synchronous condenser after a fault is: ; in, and These are the d-axis sub-transient time constant and the transient time constant, respectively; The transfer function of a traditional synchronous condenser excitation system; For the direct-axis synchronous reactor of a traditional synchronous condenser; For traditional synchronous condensers, the direct-axis transient synchronous reactor The parameters of the superconducting camera converter (SSC) and the conventional camera converter (CSC) are compared in the table below:

[0023] Furthermore, we can obtain the reactive power output increment. and the increase in reactive current It mainly depends on the subtransient reactance Due to the superconducting camera's d-axis subtransient reactance... The transient reactance is significantly smaller than that of a traditional synchronous condenser. Therefore, when the terminal voltage of a traditional synchronous condenser changes by the same amount, the superconducting synchronous condenser can generate much greater reactive power. For example... Figure 2 As shown, when faced with a severe voltage drop caused by a major fault in a new power system with a large number of new energy devices connected to it, the system connected to a traditional synchronous condenser collapses, while the superconducting synchronous condenser can effectively suppress the voltage drop and maintain the stability of the system.

[0024] Superconducting camera excitation circuit such as Figure 3 As shown, the excitation circuit of the superconducting camera includes a transformer, parallel three-phase uncontrolled rectifier bridges Z1 and Z2, input filter inductor L2, input filter capacitor C2, switching devices G4i (i=1,2,3,4), diodes D4i (i=1,2,3,4), energy storage inductor L4i (i=1,2,3,4), and output filter capacitor C3. G4i, D4i, L4i, and C3 constitute a four-phase interleaved parallel DC / DC circuit, providing high-precision excitation current for the superconducting camera excitation circuit. Rf and Lf represent the resistance and inductance of the superconducting camera excitation circuit.

[0025] The superconducting phase converter excitation circuit employs a four-phase interleaved parallel technology. By utilizing the mutual cancellation of inductor current ripple during phase-shifted operation in multi-phase circuits, it effectively reduces output current ripple, thereby decreasing the size and weight of the filter and the entire unit. By increasing the number of parallel phases to share the large current and improve the power rating, it significantly reduces the current and switching stress and switching losses of individual devices. Furthermore, while increasing the equivalent switching frequency of the converter, it further reduces the size of filter components, improves system efficiency, and enhances dynamic performance. In the superconducting phase converter excitation circuit, each phase's Buck branch uses silicon carbide fully controlled devices as the main switches. Compared to traditional IGBTs, these devices have lower conduction and switching losses, higher allowable junction temperature, and faster switching speeds, which helps maintain good efficiency and current waveforms at higher switching frequencies.

[0026] Static synchronous compensators (SSCs) achieve rapid reactive current regulation based on power electronic converters, enabling them to respond to voltage deviations and are suitable for rapidly suppressing overshoot and transient oscillations during the voltage recovery phase after fault clearing. SSCs can utilize voltage-source inverters, which have low conduction losses and the ability to prevent overvoltage of power devices. Figure 4 As shown, U s This represents the voltage of the busbar at the grid connection point; R Equivalent resistance; L 1 represents the inductor connected to the reactor, used to filter high-order harmonics and serve as the energy exchange medium between the inverter and the grid. The static synchronizing compensator controls the amplitude and phase of the voltage at the grid connection point bus. R and L Current is generated on 1, thereby realizing the exchange of reactive power with the power grid.

[0027] The coordinated control module can select the appropriate operating mode based on the comparison result of the grid connection point bus voltage relative to the preset dead zone. Operating modes include fault support mode, recovery suppression mode, and steady-state mode. The preset dead zone defines the allowable voltage fluctuation range during normal operation.

[0028] When the voltage at the grid connection point bus drops below the lower limit of the preset dead zone, it indicates a voltage dip fault at the grid connection point bus. The coordinated control module then controls the reactive power compensation control system to enter fault support mode. In fault support mode, the reactive power compensation control system uses a superconducting synchronous condenser as the leading device, working together with a fast-responding static synchronous compensator to inject reactive power into the grid connection point bus, thereby suppressing further voltage dips and accelerating voltage recovery.

[0029] When the voltage at the grid connection point bus exceeds the upper limit of this range, it indicates that the grid connection point bus is in the voltage recovery phase after fault clearance and there is an overvoltage risk. The coordinated control module controls the reactive power compensation control system to enter the recovery suppression mode. In the recovery suppression mode, the reactive power compensation control system uses the static synchronous compensator as the leading device, prioritizing the execution of commands to absorb reactive power, thereby quickly suppressing voltage overshoot and transient oscillations.

[0030] When the voltage at the grid connection point bus remains within the preset dead zone range, the reactive power compensation control system operates in steady-state mode, with the primary objective of maintaining the stability of the grid connection point bus voltage.

[0031] In this embodiment, the reactive power compensation control system fully leverages the large-capacity support advantage of the superconducting synchronous condenser in fault support mode to suppress further voltage drops at the grid connection point bus. In recovery suppression mode, it can utilize the fast response characteristics of the static synchronous compensator to suppress voltage overshoot, achieving stable voltage improvement throughout the fault process. This system is suitable for weak grid scenarios with a high proportion of renewable energy access.

[0032] In one embodiment, when the bus voltage at the grid connection point is within a preset dead zone, the reactive power compensation control system is controlled to enter a steady-state mode. In the steady-state mode, the reactive power compensation control system uses a static synchronous compensator as the main reactive power regulation device. Furthermore, the superconducting camera enables a reactive power output limiting strategy in steady-state mode, limiting the reactive power output of the superconducting camera to a preset range.

[0033] Specifically, when the bus voltage at the grid connection point is within the preset dead zone range, the coordinated control module controls the reactive power compensation control system to enter steady-state mode. In steady-state mode, the reactive power compensation control system primarily aims to suppress small disturbances, maintain voltage stability, and ensure the safe operation of the equipment.

[0034] At this point, the static synchronous compensator (SRC) generates reactive power regulation commands by combining Q-V droop control with voltage closed-loop control. The droop coefficient is set to a relatively small value, allowing the SRC to regulate the voltage deviation and avoid amplifying measurement noise or causing small oscillations due to excessive regulation. The reactive power change rate limit is set to a small value, allowing the reactive power output to change gradually and suppressing voltage fluctuations.

[0035] Meanwhile, the superconducting camera employs a reactive power output limiting strategy in steady-state mode to restrict its reactive power output to a preset small range in order to avoid excessive reactive power input during voltage disturbance recovery, which could lead to overshoot of the amplified voltage.

[0036] In one embodiment, the reactive power compensation control system further includes a superconductivity margin monitoring module, which is used to monitor the superconductivity margin index generated by the superconducting camera. The smaller the superconductivity margin index, the closer the superconducting camera is to losing quench. The superconductivity margin monitoring module monitors the winding temperature and magnetic field strength of the excitation circuit of the superconducting phase converter online, dynamically calculates the upper limit of the excitation current, and generates a superconductivity margin index based on the upper limit of the excitation current and the critical quench current. The superconductivity margin index is negatively correlated with the upper limit of the excitation current.

[0037] Specifically, for high-temperature superconducting synchronous condensers, the upper limit of the excitation current is constrained not only by hardware limitations such as the rated current of the excitation power unit, the thermal limit of the devices, and the DC bus capacity, but also by the winding temperature T and magnetic field B of the excitation circuit of the superconducting condenser. The reactive power compensation control system also includes a superconductivity margin monitoring module. This module can collect the winding temperature T and magnetic field strength B of the excitation circuit of the superconducting condenser in real time. Based on the monitored winding temperature T and magnetic field strength B, the superconductivity margin monitoring module can calculate the allowable upper limit of the excitation current under the current operating conditions. I fmax The calculation formula is: ; in, It is the upper limit of the hardware current of the excitation power supply coil; It is a safety factor to avoid approaching the critical point; The critical quench current at the current temperature and magnetic field is obtained by looking up a table.

[0038] After obtaining the upper limit of the excitation current I fmax Subsequently, the superconductivity margin monitoring module further combines the current actual excitation current... I f and critical overrun current Calculate the superconductivity margin index M x : ; in, This represents the dangerous threshold for superconductivity margin. When... At that time, further incentives are prohibited.

[0039] In one embodiment, the connection diagram of the reactive power compensation control system is as follows: Figure 5 As shown, the system includes: a grid connection point bus, a static synchronous compensator, a superconducting phase converter, a superconducting margin monitoring module, a coordination control module, a superconducting phase converter excitation control module, a superconducting phase converter excitation circuit, and a measurement and sampling unit.

[0040] The measurement and sampling unit collects the grid-connected bus voltage in real time and sends it to the coordination control module. The coordination control module compares the voltage with the preset dead zone to determine whether the reactive power compensation control system enters fault support, recovery suppression, or steady-state mode, and issues mode commands to the static synchronous compensator (SRC) and the superconducting phase-shifting transformer (SMT) excitation circuit. The SRC generates reactive power commands based on parameters such as the droop coefficient adjusted according to the mode. The SMT excitation circuit, combined with the reactive power commands and the superconducting margin index provided by the superconducting margin monitoring module, dynamically constrains the excitation current change rate, enabling the SMT and SRC to provide or absorb reactive power to the grid-connected bus in different modes, either in a dominant or cooperative manner, thus achieving voltage stability support and overshoot suppression throughout the fault process.

[0041] In one embodiment, such as Figure 6 As shown, the collaborative control module adopts a combination of Q-V droop control and voltage closed-loop control to generate reactive power regulation commands for the static synchronous compensator according to the following steps: Step 601: The collaborative control module acquires the measured value of the reactive power currently output or absorbed by the static synchronous compensator, as well as the per-unit value of the bus voltage at the grid connection point; Step 602: The collaborative control module normalizes the reactive power measurement value according to the rated capacity of the static synchronous compensator to obtain the reactive power per-unit value; Step 603: The collaborative control module takes the voltage value according to the preset minimum lower limit of the per-unit voltage of the grid connection point bus. Based on the taken voltage and reactive power per-unit value, it calculates the droop compensation amount according to the preset droop coefficient. Step 604: The collaborative control module superimposes the per-unit value of the grid connection point bus voltage with the droop compensation amount to obtain the voltage control amount; Step 605: The collaborative control module filters and shapes the voltage control quantity to obtain a smooth voltage signal; Step 606: The cooperative control module compares the smoothed voltage signal with the preset reference voltage to obtain the voltage error, and after the voltage error is compensated for lead-lag, it is input into the PI regulator to generate the reactive power regulation command of the static synchronous compensator. Among them, the droop coefficient of the static synchronous compensator, the filtering time constant for filtering and shaping the voltage control quantity, and the upper limit of the reactive power change rate of the static synchronous compensator are adjusted according to the mode of the reactive power compensation control system.

[0042] Specifically, the coordinated control module acquires the measured reactive power values ​​of the static synchronizing compensator in real time through the measurement sampling unit. Q m and the per-unit value of the bus voltage at the grid connection point. U pcc .

[0043] The collaborative control module measures reactive power. Q m Based on the rated capacity of the static synchronizing compensator Standardize to obtain the per-unit value of reactive power. .

[0044] The collaborative control module operates according to the preset minimum per-unit value of the grid connection point bus voltage. For example, the voltage value is processed using 0.2 pu), i.e. U pcc < U min Then take U min Otherwise take U pcc To avoid numerical divergence.

[0045] Voltage based on value U pcc and reactive power per unit value Q pu According to the preset droop coefficient Calculate the sag compensation amount The formula for calculating the sag compensation amount is: .

[0046] The collaborative control module will set the per-unit value of the bus voltage at the grid connection point. U pcc With sagging compensation Superimpose the values ​​to obtain the voltage control quantity. .

[0047] The collaborative control module controls the voltage quantity. U c For filtering and shaping, a first-order low-pass filter is typically used. The filtering time constant is adjusted according to the operating mode to output a smooth voltage signal. To suppress measurement noise and high-frequency disturbances.

[0048] The collaborative control module will smooth the voltage signal. With preset reference voltage U ref By comparison, the voltage error is obtained. .

[0049] Voltage error e After passing through the lead-lag compensator, the input is fed into the PI regulator to generate a reactive current command, which is then converted into a trigger pulse for the static synchronous compensator, enabling rapid tracking of reactive power.

[0050] It should be noted that in the above process, the droop coefficient, filter time constant, and upper limit of reactive power change rate of the static synchronous compensator are dynamically adjusted according to the operating mode of the reactive power compensation control system. In steady-state mode, the droop coefficient A relatively gentle slope is used to allow the static synchronous compensator to gently adjust the voltage deviation, avoiding excessive simplification that amplifies noise; reactive power change rate Setting the upper limit to a smaller value allows for gradual changes in reactive power output, suppressing steady-state oscillations; the filter time constant... A relatively large value is used to prioritize the suppression of measurement noise and high-frequency disturbances, thereby maintaining voltage stability.

[0051] In fault-support mode, the sag coefficient Increasing it to a larger value causes the same voltage deviation to trigger a larger reactive power command demand, quickly boosting reactive power support; reactive power change rate The upper limit is set to a large value to allow the static synchronous compensator to reach its capacity boundary as quickly as possible; the filter time constant Lower the value to a smaller level to reduce filtering and decrease control lag, thereby improving response speed.

[0052] In recovery inhibition mode, the droop coefficient and time constant Set to a value between steady-state mode and fault-tolerant mode to enhance suppression; the reactive power change rate is set asymmetrically: absorbing the rate of change in the reactive power direction. The upper limit allows for faster changes, while the rate of change in the injected reactive power direction... The upper limit is set more conservatively to prevent the voltage from swinging back and forth during the recovery period, and to prioritize the suppression of voltage overshoot and oscillation.

[0053] In one embodiment, under steady-state mode, the reactive power compensation control system employs a conservative control strategy to maintain the superconducting safety margin and suppress small disturbances. For the superconducting phase modulator, the reactive power output is limited to a preset limit. Within this range, the rate of change of the excitation current is set to a lower upper limit. .

[0054] In one embodiment, under fault-support mode, the reactive power compensation control system uses a superconducting synchronous condenser as the primary reactive power source, and works in conjunction with a static synchronous compensator to provide dynamic reactive power support, including: The reactive power limiting parameter of the superconducting camera is adjusted to the first limit, which is greater than the second limit. The second limit is the reactive power limiting parameter of the superconducting camera in steady-state mode. Furthermore, the upper limit of the excitation current change rate of the superconducting camera is set to be positively correlated with the superconductivity margin index. Furthermore, the upper limit of the reactive power change rate and the droop coefficient of the static synchronous compensator are set to be higher than the corresponding parameters in the steady-state mode, and the filter time constant is set to be lower than the filter time constant in the steady-state mode.

[0055] Specifically, when the voltage of the grid connection point bus is lower than the lower limit of the preset dead zone, it indicates that a voltage drop fault has occurred at the grid connection point bus. The coordinated control module controls the reactive power compensation control system to enter the fault support mode. At this time, the reactive power compensation control system sets the superconducting synchronous condenser as the dominant reactive power source and coordinates with the static synchronous compensator to provide dynamic reactive power support.

[0056] At this point, the reactive power output limit of the superconducting camera is reduced from the second limit in steady-state mode. Switch to first limiter The upper limit of the excitation current change rate of the superconducting tuner is set to This makes the upper limit of the rate of change of the excitation current. With real-time superconductivity margin index M sc Positive correlation: ; .

[0057] With sufficient margin ( M sc When ≥M1), the reference rate is allowed. r 0 (1) Rapidly increase incentives to provide strong support, as margin decreases (0≤ M sc < M 1) When in proportion (γ( M sc )= M sc / M 1) Tighten the rate of change to prevent exceeding the limit.

[0058] Adjust the QV droop control parameter of the static synchronous compensator, and change its droop coefficient from... Increase to The upper limit of the reactive power change rate is increased from Increase to and the filter time constant from Reduce to This speeds up its initial response.

[0059] In this embodiment, the static synchronous compensator provides a fast reactive power response and quickly reaches the capacity limit, while the superconducting phase modulator removes the output limit under the constraint of safe superconductivity margin and provides large-capacity continuous support. The two work together to effectively suppress voltage drops and improve the recovery trend.

[0060] In one embodiment, in the recovery suppression mode, the reactive power compensation control system, primarily driven by the static synchronous compensator, executes reactive power absorption commands to suppress voltage overshoot, including: The reactive power limiting parameter of the superconducting camera is adjusted to the third limit, which is less than the first limit and greater than the second limit. Furthermore, the upper limit of the excitation current change rate of the superconducting camera is set between the upper limit of the excitation current change rate in steady-state mode and fault support mode. The upper limit of the excitation current change rate is set to an asymmetric constraint, with a larger upper limit of the excitation current change rate in the de-excitation direction and a smaller upper limit of the excitation current change rate in the up-excitation direction. Furthermore, the droop coefficient, filter time constant, and upper limit of reactive power change rate of the static synchronous compensator are set to be between the corresponding parameters of steady-state mode and fault support mode. The upper limit of reactive power change rate is set as an asymmetric constraint, with a larger upper limit of reactive power change rate in the reactive power absorption direction and a smaller upper limit of reactive power change rate in the reactive power output direction.

[0061] Specifically, when the coordinated control module detects that the voltage at the grid connection point bus is higher than the preset dead zone upper limit, the reactive power compensation control system determines that it needs to enter the recovery suppression mode. In the recovery suppression mode, the reactive power compensation control system uses the static synchronous compensator as the main controller to execute reactive power absorption commands to suppress voltage overshoot.

[0062] The reactive power limiting parameter of the superconducting camera is set from the first limiting parameter in fault support mode. Tightened to the third limit Third limit Second amplitude limit between steady-state modes With the first limit Between these, to suppress its continued output of reactive power.

[0063] The upper limit of the excitation current change rate of the superconducting tuner is set between the corresponding values ​​of the steady-state mode and the fault support mode, and an asymmetric constraint is adopted, that is, a larger upper limit of the change rate is set in the de-excitation direction. To allow the excitation current to decrease rapidly and quickly weaken reactive power support, a small upper limit for the rate of change is set in the excitation direction. This is to limit the excitation from rising again and prevent the voltage from increasing.

[0064] Adjust the control parameters of the static synchronous compensator and set its droop coefficient to... The filter time constant is set to The upper limit of reactive power change rate is set to These parameter values ​​all fall between the corresponding parameters of its steady-state mode and fault-support mode. Furthermore, an asymmetric constraint is applied to the upper limit of the reactive power change rate: a larger upper limit is set in the reactive power absorption direction to quickly suppress overvoltage, while a smaller upper limit is set in the reactive power output direction to prevent exacerbating voltage oscillations.

[0065] In this embodiment, the static synchronous compensator can preferentially and quickly absorb excess reactive power to suppress voltage overshoot, while the superconducting phase modulator is constrained to a follower and auxiliary role. Together, they effectively reduce the overvoltage peak during the recovery period and weaken the oscillation amplitude.

[0066] In one embodiment, the upper limit of the excitation current change rate in the de-excitation direction is positively correlated with the overvoltage degree and negatively correlated with the superconductivity margin index; the upper limit of the excitation current change rate in the up-excitation direction is negatively correlated with the absolute value of the reactive power of the static synchronous compensator and positively correlated with the superconductivity margin index.

[0067] Specifically, the upper limit of the rate of change of excitation current in the de-excitation direction. ) is set to a dynamic value, calculated as follows: .

[0068] in, The base excitation change rate, k v and k m The weighting coefficient is greater than zero.

[0069] This formula indicates that the upper limit of the excitation current change rate in the de-excitation direction is positively correlated with the degree of overvoltage; the more severe the voltage overshoot, the faster the allowable de-excitation speed. Furthermore, the upper limit of the excitation current change rate is related to the superconductivity margin index M. sc There is a negative correlation, meaning that the lower the superconductivity margin, the higher the upper limit of the excitation current change rate. The purpose is to reduce the excitation current more quickly in the event of a risk in order to protect the equipment and rapidly weaken the reactive power support.

[0070] Upper limit of the rate of change of excitation current in the up-excitation direction The formula for calculation is: .

[0071] in, As the benchmark excitation rate, k M and k Q For weighting coefficients greater than zero, | Q sta | represents the absolute value of reactive power absorbed by the static synchronous compensator.

[0072] This formula represents the upper limit of the rate of change of excitation current in the up-excitation direction and the superconductivity margin index. M sc It is positively correlated, meaning that the higher the superconductivity margin index, the larger the allowable up-excitation rate, and the lower the superconductivity margin index, the slower the up-excitation rate.

[0073] Furthermore, the upper limit of the rate of change of excitation current in the up-excitation direction is related to the reactive power absorbed by the static synchronizing compensator. Q sta | Negative correlation, that is, the more reactive power absorbed by the static synchronous compensator, the stricter the restriction on the excitation of the superconducting phase modulator, thereby preventing the two from conflicting and aggravating voltage oscillation.

[0074] Based on the same concept, this application also provides a reactive power compensation control method, which applies the above-mentioned reactive power compensation control system and includes: The system collects the voltage of the grid connection point bus. When the voltage of the grid connection point bus is less than the lower limit of the preset dead zone, the reactive power compensation control system is controlled to enter the fault support mode. When the voltage of the grid connection point bus is greater than the upper limit of the preset dead zone, the reactive power compensation control system is controlled to enter the recovery suppression mode. When the voltage of the grid connection point bus is within the preset dead zone, the reactive power compensation control system is controlled to enter the steady-state mode.

[0075] Specifically, the bus voltage at the sampling point of grid connection is... and with reference voltage The voltage deviation was obtained by comparison: Simultaneously, it reads status signals from protection devices / circuit breakers, etc., for abnormal operating condition identification and control interlocking. Preset voltage dead zone interval. (For example , ).

[0076] Determine the bus voltage at the grid connection point Is it within the preset dead zone range? If it meets the requirements... It enters steady-state mode. If it is not within the preset dead zone, further judgment is required. Enter fault support mode; if It enters the recovery inhibition mode.

[0077] When the grid connection point bus voltage is within the preset dead zone, the static synchronous compensator (SRC) serves as the primary reactive power regulation device. The SRC generates reactive power regulation commands using a combination of Q-V droop control and voltage closed-loop control to achieve stable grid connection point voltage regulation and reactive power sharing among multiple devices. Control is based on the per-unit value of the grid connection point voltage. Real-time reactive power measurement value of static synchronous compensator As input, the reactive power output of the static synchronous compensator is changed through droop calculation, filtering and shaping, and closed-loop adjustment of the output control angle.

[0078] QV droop allows the static synchronous compensator to continuously adjust the voltage deviation, maintaining the voltage near the dead zone. QV droop steady-state adjustment is gentle, interference-resistant, and easily coexists with superconducting synchronous modulators.

[0079] Meanwhile, the superconducting camera employs a reactive power output limiting / suppression strategy during the steady-state phase to limit reactive power output within a preset range, thereby preventing excessive reactive power injection during voltage disturbance recovery and amplifying voltage overshoot.

[0080] In fault support mode, the reactive power output limiting of the superconducting camera is lifted, allowing it to maximize its reactive power support within the equipment's capacity limits. At this time, the static synchronizing compensator (SRC) maintains a fast dynamic response, controlling reactive power output through Q-V droop control. However, the SRC is limited by its rated capacity and quickly reaches its limit. The superconducting camera then lifts its reactive power limiting to provide large-capacity support, taking on the main reactive power supply, while the SRC continues to provide fast component and dynamic adjustment. Together, they provide large-capacity dynamic reactive power support to improve voltage support capability during faults, reduce voltage dips, and improve voltage recovery trends.

[0081] When overvoltage or overshoot tends to occur during voltage recovery after fault clearance. When the time comes, it enters the recovery suppression mode. The static synchronous compensator preferentially enters the reactive power absorption working area (negative reactive power) based on the Q-V droop characteristics to quickly suppress voltage overshoot and fluctuations; the superconducting synchronous modulator resumes the strategy of "suppression and amplitude limiting" to limit the reactive power output amplitude, avoids overcompensation caused by adjusting in the same direction as the static synchronous compensator, thereby reducing the peak overvoltage during the recovery period and weakening the oscillation amplitude.

[0082] It should be noted that the controller continuously checks for and maintains the voltage when it returns to the dead zone. When Back And maintain the preset time. Then, execute the exit from emergency mode switching process to avoid frequent jitter switching.

[0083] Based on the same concept, this application also provides a computer storage medium storing a processing program, which executes the above-described reactive power compensation control method when running.

[0084] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this application is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means.

[0085] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The above are merely preferred embodiments of this application and are not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application are included within the scope of protection of this application.

Claims

1. A reactive power compensation control system for a receiving-end power grid, characterized in that, The reactive power compensation control system includes: The measurement sampling unit is used to sample the voltage of the bus at the grid connection point; The superconducting camera is electrically connected to the grid connection point bus. A static synchronous compensator is electrically connected to the grid connection point bus. The collaborative control module is configured to adjust based on the bus voltage at the grid connection point. When the bus voltage at the grid connection point is within a preset dead zone, the reactive power compensation control system is controlled to enter a steady-state mode. In this steady-state mode, the reactive power compensation control system uses the static synchronous compensator as the main reactive power regulation device. Furthermore, the superconducting camera in the steady-state mode enables a reactive power output limiting strategy to limit the reactive power output of the superconducting camera within a preset range. When the voltage at the grid connection point bus is less than the lower limit of the preset dead zone voltage, the reactive power compensation control system is controlled to enter the fault support mode. In the fault support mode, the reactive power compensation control system uses the superconducting phase modulator as the main reactive power source and works in conjunction with the static synchronous compensator to provide dynamic reactive power support. The reactive power limiting parameter of the superconducting phase modulator is adjusted to a first limit, which is greater than a second limit. The second limit is the reactive power limiting parameter of the superconducting phase modulator in the steady-state mode. Furthermore, the upper limit of the excitation current change rate of the superconducting phase modulator is set to be positively correlated with the superconducting margin index. In addition, the upper limit of the reactive power change rate and the droop coefficient of the static synchronous compensator are set to be higher than the corresponding parameters in the steady-state mode, and the filtering time constant is set to be lower than the filtering time constant in the steady-state mode. When the voltage at the grid connection point bus exceeds the upper limit of the preset dead zone voltage, the reactive power compensation control system is controlled to enter a recovery suppression mode. In the recovery suppression mode, the reactive power compensation control system, with the static synchronous compensator as the main controller, executes the reactive power absorption command, adjusts the reactive power limiting parameter of the superconducting modulator to a third limit, which is less than the first limit and greater than the second limit. Furthermore, the upper limit of the excitation current change rate of the superconducting modulator is set between the upper limits of the excitation current change rate in steady-state mode and fault support mode, and the upper limit of the excitation current change rate is set as an asymmetric constraint, with a larger upper limit in the de-excitation direction and a smaller upper limit in the up-excitation direction. Additionally, the droop coefficient, the filter time constant, and the upper limit of the reactive power change rate of the static synchronous compensator are set between the corresponding parameters in steady-state mode and fault support mode, and the upper limit of the reactive power change rate is set as an asymmetric constraint, with a larger upper limit in the reactive power absorption direction and a smaller upper limit in the reactive power output direction.

2. The reactive power compensation control system according to claim 1, characterized in that, The collaborative control module adopts a combination of Q-V droop control and voltage closed-loop control to generate reactive power adjustment commands for the static synchronous compensator according to the following steps: The collaborative control module acquires the measured value of the reactive power currently output or absorbed by the static synchronous compensator, as well as the per-unit value of the grid connection point bus voltage. The collaborative control module normalizes the reactive power measurement value according to the rated capacity of the static synchronous compensator to obtain the reactive power per-unit value. The collaborative control module takes voltage values ​​according to the preset minimum limit of the per-unit voltage of the grid connection point bus, and calculates the droop compensation amount based on the voltage values ​​and the per-unit reactive power value according to the preset droop coefficient. The collaborative control module superimposes the per-unit value of the grid connection point bus voltage with the droop compensation amount to obtain the voltage control amount; The collaborative control module filters and shapes the voltage control quantity to obtain a smooth voltage signal; The collaborative control module compares the smoothed voltage signal with the preset reference voltage to obtain the voltage error, and after the voltage error is compensated for lead-lag, it inputs the voltage error into the PI regulator to generate the reactive power regulation command of the static synchronous compensator. The droop coefficient of the static synchronous compensator, the filtering time constant for filtering and shaping the voltage control quantity, and the upper limit of the reactive power change rate of the static synchronous compensator are adjusted according to the mode of the reactive power compensation control system.

3. The reactive power compensation control system according to claim 1, characterized in that, The upper limit of the excitation current change rate in the de-excitation direction is positively correlated with the degree of overvoltage and negatively correlated with the superconductivity margin index.

4. The reactive power compensation control system according to claim 1, characterized in that, The upper limit of the excitation current change rate in the up-excitation direction is negatively correlated with the absolute value of the reactive power of the static synchronous compensator and positively correlated with the superconductivity margin index.

5. The reactive power compensation control system according to claim 1, characterized in that, The reactive power compensation control system also includes a superconductivity margin monitoring module, which is used to monitor the superconductivity margin index generated by the superconducting camera. The smaller the superconductivity margin index, the closer the superconducting camera is to losing quench. The superconductivity margin monitoring module monitors the winding temperature and magnetic field strength of the excitation circuit of the superconducting phase converter online, dynamically calculates the upper limit of the excitation current, and generates the superconductivity margin index based on the upper limit of the excitation current and the critical quench current. The superconductivity margin index is negatively correlated with the upper limit of the excitation current.

6. A reactive power compensation control method, characterized in that, The reactive power compensation control method applies the reactive power compensation control system according to any one of claims 1 to 5, and the reactive power compensation control method includes: The system collects the voltage of the grid connection point bus. If the voltage of the grid connection point bus is less than the lower limit of the preset dead zone, the system controls the reactive power compensation control system to enter the fault support mode. If the voltage of the grid connection point bus is greater than the upper limit of the preset dead zone, the system controls the reactive power compensation control system to enter the recovery suppression mode. If the voltage of the grid connection point bus is within the preset dead zone, the system controls the reactive power compensation control system to enter the steady-state mode.

7. A computer storage medium, characterized in that, The computer storage medium stores a processing program, which executes the reactive power compensation control method as described in claim 6 when it runs.

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