A method and device for reactive power compensation at the end of a transformer area power grid

Abstract

The application provides a transformer area power grid end reactive power compensation method and device, wherein the transformer area power grid end reactive power compensation method comprises the following steps: a sampling module measures the voltage of a point of common coupling at the end of a transformer area power grid; an impedance calculation unit obtains the load end impedance at a moment; a reactive power calculation unit calculates the required reactive power compensation power of the end of the transformer area power grid at the moment according to the voltage of the point of common coupling at the end of the transformer area power grid at the moment and the load end impedance at the moment; a current instruction generation unit generates a target compensation current instruction according to the target compensation current required to be output according to the reactive power compensation power; a PWM unit generates a compensation current control signal according to the target compensation current instruction; and IGBT outputs the compensation current of the end of the transformer area power grid at the moment to the point of common coupling according to the compensation current control signal. The problem that the dq axis decoupling control algorithm is difficult to accurately and precisely control three-phase voltage and current is effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of reactive power compensation of power systems, and in particular to a method and device for reactive power compensation at the end of a transformer area power grid. BACKGROUND

[0002] Due to the diversity and complexity of electrical equipment at the end of a transformer area power grid, the problem of reactive power imbalance is more prominent. On the one hand, a large number of inductive loads such as electric motors and transformers consume a large amount of reactive power during operation, which reduces the power factor of the power grid, increases line loss and voltage drop, and affects power quality and power supply reliability. On the other hand, with the large-scale access of distributed power sources such as photovoltaic and wind power at the end of the transformer area power grid, the intermittency and volatility of their output power will further exacerbate the imbalance of reactive power.

[0003] In order to determine the reactive power state at the end of the transformer area power grid, a specific disturbance signal is usually injected into the transformer area, and the electrical response of the transformer area after injecting the disturbance signal is monitored and analyzed to achieve the determination. In the prior art, the patent document with the application publication number CN120527947A provides a control method and system for improving the generation accuracy of SVG disturbance signals. The technical solution is that the attenuation of the disturbance signal caused by the SVG direct current voltage control is calculated by an observer, and after phase compensation, it is superimposed with the given value of the direct current voltage as the input of the outer ring of the voltage controller. After the difference between the direct current voltage feedback, the outer ring output of the voltage controller is obtained, and the instruction current disturbance signal is superimposed as the input of the inner ring of the current controller, and the current inner ring controller is controlled by the PWM modulation instruction to control the operation of the SVG. The influence of the direct current voltage outer ring on the actual current disturbance signal is significantly reduced, so that the SVG can still output accurate actual current disturbance signal when injecting each frequency instruction current disturbance signal.

[0004] However, the SVG disturbance signal described above is injected into the d-axis component and q-axis component by the dq-axis decoupling control algorithm, and after PI closed-loop control, it is inversely transformed into a three-phase signal and converted into a PWM signal for control. It is suitable for three-phase balanced occasions. For the three-phase imbalance that often exists at the end of the transformer area power grid, the dq-axis decoupling control algorithm is difficult to accurately control the three-phase voltage and current, resulting in that the injected disturbance signal cannot accurately reflect the actual voltage condition, thereby affecting the accurate determination of the reactive power state at the end of the transformer area power grid.

[0005] Moreover, this method has poor adaptability when facing the complex power environment at the end of the transformer area power grid and the large-scale access of distributed power sources, and may not be able to respond in time to the changes in reactive power at the end of the transformer area power grid, resulting in untimely or inaccurate reactive power compensation. SUMMARY

[0006] The purpose of this invention is to provide a method and apparatus that can effectively solve the problem of accurately judging the reactive power status under three-phase imbalance at the end of the distribution network, and can respond in a timely manner to changes in reactive power at the end of the distribution network and perform reactive power compensation in a timely manner.

[0007] This application provides a method for reactive power compensation at the end of a distribution network, the specific technical solution of which is: sampling module measurement. Voltage at the common coupling point of the power grid at the time of the distribution area ;

[0008] Impedance calculation unit obtains Constant load impedance ;

[0009] The reactive power calculation unit is based on the above. Voltage at the common coupling point of the power grid at the time distribution area and stated Constant load impedance calculate Reactive power compensation required at the end of the power grid at any time ,in ;

[0010] The current command generation unit generates the current command based on the reactive power compensation. Calculate the target compensation current required for output. Generate the target compensation current command, where ;

[0011] The PWM unit generates a compensation current control signal according to the target compensation current command;

[0012] The IGBT outputs to the common coupling point according to the compensation current control signal. Compensation current at the end of the power grid in the time zone .

[0013] Furthermore, the method also includes the following steps:

[0014] The sampling module is set with a sampling period and also measures... Voltage at the common coupling point of the power grid at the time of the distribution area ;

[0015] The disturbance generation unit in Time and Injecting current disturbances into the common coupling point at intervals ;

[0016] The impedance calculation unit first calculates Voltage change at the common coupling point at the end of the power grid in the time zone ,in - ;

[0017] recalculating the load end impedance wherein .

[0018] Further, the sampling period comprises a continuous sampling period T and an intermittent sampling period t, the intermittent sampling period t being set within the continuous sampling period T, the intermittent sampling period t being less than the continuous sampling period T;

[0019] the sampling frequency of the continuous sampling period T and the intermittent sampling period t is the same;

[0020] when the data collected in the intermittent sampling period t deviates from the data collected in the continuous sampling period T within a preset range, the continuous sampling period T is determined as an effective sampling period;

[0021] when the data collected in the intermittent sampling period t deviates from the data collected in the continuous sampling period T beyond the preset range, the continuous sampling period T is shortened to obtain a shortened continuous sampling period , the data is resampled in the shortened continuous sampling period and compared with the data collected in the intermittent sampling period t again.

[0022] Further, when the data collected in the shortened continuous sampling period deviates from the data collected in the intermittent sampling period t beyond the preset range, the continuous sampling period T is further shortened to obtain a continuously shortened continuous sampling period , the data is resampled in the continuously shortened continuous sampling period and compared with the data collected in the intermittent sampling period t again, until the data collected in the continuously shortened continuous sampling period deviates from the data collected in the intermittent sampling period t within the preset range.

[0023] Further, the disturbance generation unit comprises a first disturbance generation circuit, the first disturbance generation circuit comprises a phase-locked loop circuit, a voltage control circuit, a disturbance injection circuit and a current control circuit,

[0024] The phase-locked loop circuit comprises a phase-locked loop (PLL), the phase-locked loop circuit receives a point of common coupling voltage , outputs a terminal phase angle of a substation power grid ;

[0025] The voltage control circuit comprises a first subtractor, a first PI controller and an inverse PARK transformation module, the voltage control circuit receives a direct current side voltage , a direct current side reference voltage and the terminal phase angle of the substation power grid , outputs an a-phase outer loop output current instruction , a b-phase outer loop output current instruction and a c-phase outer loop output current instruction ;

[0026] The disturbance injection circuit comprises a disturbance signal given module, a second subtractor, a third subtractor and a fourth subtractor, the disturbance injection circuit receives the terminal phase angle of the substation power grid , the a-phase outer loop output current instruction , the b-phase outer loop output current instruction and the c-phase outer loop output current instruction , outputs an a-phase intermediate disturbance current given instruction , a b-phase intermediate disturbance current given instruction and a c-phase intermediate disturbance current given instruction ;

[0027] The current control circuit comprises a first PR controller, a second PR controller, a third PR controller, a fifth subtractor, a sixth subtractor, a seventh subtractor, a first adder, a second adder and a third adder, the current control circuit receives the a-phase intermediate disturbance current given instruction , the b-phase intermediate disturbance current given instruction , the c-phase intermediate disturbance current given instruction , an a-phase current at the terminal of the substation power grid , a b-phase current at the terminal of the substation power grid , a c-phase current at the terminal of the substation power grid , an a-phase voltage at the terminal of the substation power grid , a b-phase voltage at the terminal of the substation power grid , a c-phase voltage at the terminal of the substation power grid , outputs a first disturbance current control signal.

[0028] Further, the voltage control circuit calculates a voltage fluctuation from the DC side reference voltage input to the first subtractor and the DC side voltage , adjusts the voltage fluctuation through the first PI controller and the inverse PARK transformation module to obtain the a-phase outer loop output current command , the b-phase outer loop output current command and the c-phase outer loop output current command ;

[0029] The disturbance injection circuit inputs the a-phase outer loop output current command and the a-phase disturbance current given command to the second subtractor to obtain the a-phase intermediate disturbance current given command , inputs the b-phase outer loop output current command and the b-phase disturbance current given command to the third subtractor to obtain the b-phase intermediate disturbance current given command , and inputs the c-phase outer loop output current command and the c-phase disturbance current given command to the fourth subtractor to obtain the c-phase intermediate disturbance current given command ;

[0030] The current control circuit inputs the a-phase intermediate disturbance current given command and the a-phase current at the end of the power grid of the transformer area to the fifth subtractor to obtain the a-phase disturbance current , inputs the b-phase intermediate disturbance current given command and the b-phase current at the end of the power grid of the transformer area to the sixth subtractor to obtain the b-phase disturbance current , and inputs the c-phase intermediate disturbance current given command and the c-phase current at the end of the power grid of the transformer area to the seventh subtractor to obtain the c-phase disturbance current ;

[0031] The current control circuit inputs the a-phase disturbance current , the b-phase disturbance current and the c-phase disturbance current to the first PR controller, the second PR controller and the third PR controller respectively to adjust and convert into the a-phase disturbance voltage , b phase disturbance voltage and c phase disturbance voltage ;

[0032] The current control circuit inputs the a phase disturbance voltage and the a phase voltage at the end of the transformer area power grid to the first adder, inputs the b phase disturbance voltage and the b phase voltage at the end of the transformer area power grid to the second adder, and inputs the c phase disturbance voltage and the c phase voltage at the end of the transformer area power grid to the third adder to superimpose to generate the first disturbance current control signal.

[0033] Further, the disturbance generation unit further comprises a second disturbance generation circuit, the second disturbance generation circuit comprising a PARK transformation module and a disturbance compensation circuit, the PARK transformation module receiving the a phase disturbance current given instruction , the b phase disturbance current given instruction and the c phase disturbance current given instruction and converting into d-axis disturbance current instruction and q-axis disturbance current instruction in a two-phase rotating coordinate system.

[0034] The disturbance compensation circuit comprises an eighth subtractor, a ninth subtractor, a fourth adder and a fifth adder, a second PI controller, a third PI controller, a sixth adder and a seventh adder, the disturbance compensation circuit receiving the d-axis disturbance current instruction and the q-axis disturbance current instruction outputted by the PARK transformation module and outputting a second disturbance current control signal.

[0035] Further, the disturbance compensation circuit inputs the d-axis disturbance current instruction and the d-axis outer loop output current instruction to the eighth subtractor to obtain a d-axis current deviation amount, inputs the q-axis disturbance current instruction and the q-axis outer loop output current instruction to the ninth subtractor to obtain a q-axis current deviation amount.

[0036] The d-axis current deviation amount and the d-axis actual current are inputted to the fourth adder to superimpose to generate a superimposed d-axis current signal.

[0037] The q-axis current deviation amount and the q-axis actual current Input to the fifth adder for superposition generates a superimposed q-axis current signal;

[0038] The superimposed d-axis current signal and the superimposed q-axis current signal are input to the second PI controller and the third PI controller respectively for adjustment to obtain a d-axis adjustment amount and a q-axis adjustment amount;

[0039] The d-axis actual current and the q-axis actual current are decoupled by the real-time phase angle θ of the power grid to obtain a d-axis decoupled current and a q-axis decoupled current;

[0040] The d-axis decoupled current and the d-axis adjustment amount are input to the sixth adder for superposition to obtain a d-axis control amount, and the q-axis decoupled current and the q-axis adjustment amount are input to the seventh adder for superposition to obtain a q-axis control amount;

[0041] The d-axis control amount and a d-axis adjustment voltage are input to the sixth adder for superposition to obtain a d-axis control voltage, and the q-axis control amount and a q-axis adjustment voltage are input to the seventh adder for superposition to obtain a q-axis control voltage, and the d-axis control voltage and the q-axis control voltage are taken as a second disturbance current control signal.

[0042] Further, the first disturbance generation circuit and the second disturbance generation circuit are controlled by a three-phase balance judgment module, the three-phase balance judgment module monitors three-phase voltage of a point of common coupling, judges whether the point of common coupling satisfies a three-phase balance condition, and the three-phase balance judgment module will issue different control instructions to the first disturbance generation circuit and the second disturbance generation circuit according to the degree and type of imbalance:

[0043] When the point of common coupling is three-phase unbalanced, the three-phase balance judgment module controls the first disturbance generation circuit to work to generate a first disturbance current to regulate the end of the transformer area power grid to restore the balance of the three-phase voltage;

[0044] When the point of common coupling is three-phase balanced, the three-phase balance judgment module controls the second disturbance generation circuit to work to generate a second disturbance current to analyze the stability of the end of the transformer area power grid.

[0045] Another aspect of the present application provides a transformer area power grid end reactive power compensation device, the device comprises at least one processor and a memory, the memory has instructions stored therein, when the instructions are executed by the at least one processor, the steps of the method according to any one of the above are implemented.

[0046] The beneficial effects of the present application are:

[0047] The first disturbance generation circuit plays a role when the three-phase is unbalanced, generates a first disturbance current control signal through a phase-locked loop circuit, a voltage control circuit, etc., for reactive power calculation and compensation in the three-phase unbalanced state, so that the power grid reaches three-phase balance; the second disturbance generation circuit works when the three-phase is balanced, performs stability analysis on the end of the transformer area power grid, and ensures stable operation of the power grid.

[0048] By setting the continuous sampling period and the intermittent sampling period to cooperate with each other, the accuracy and reliability of the sampling data are ensured. According to the data deviation, the continuous sampling period is dynamically adjusted, which can adapt to different power grid operating states, and improves the stability and compensation effect of the system. BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 is a flow chart of the transformer area power grid end reactive power compensation method of the present application;

[0050] Figure 2 is a structural schematic diagram of the transformer area power grid end reactive power compensation method of the present application;

[0051] Figure 3 is a schematic diagram of the change of each parameter with time in the transformer area power grid end reactive power compensation method of the present application;

[0052] Figure 4 is a schematic diagram of the disturbance generation unit of the present application;

[0053] Figure 5 is a structural schematic diagram of an embodiment of the disturbance generation unit of the present application;

[0054] Figure 6 is a structural schematic diagram of an embodiment of the disturbance generation unit of the present application;

[0055] Figure 7 is a structural schematic diagram of an embodiment of the disturbance generation unit of the present application;

[0056] Figure 8 is a schematic diagram of the transformer area power grid end reactive power compensation method device of the present application;

[0057] Figure 9 is a schematic diagram of the transformer area power grid end reactive power compensation method system of the present application; DETAILED DESCRIPTION

[0058] The substation in the present application refers to the area directly supplied by the low-voltage side of the transformer in the power system, which is the basic unit of power distribution. In this area, power is output from the low-voltage side of the transformer, passes through a series of distribution lines and equipment, and is finally delivered to each power user.

[0059] The substation has strong randomness and volatility in load characteristics due to wide power supply range and diverse types of electrical equipment. Different users have different power demands at different time periods. For example, residential users will significantly increase power load by using air conditioners, lighting and other equipment during the evening peak period. Industrial users may concentrate on power consumption at specific time periods according to production plans. This uncertainty in load makes the voltage at the end of the substation grid prone to fluctuation.

[0060] The diversity and complexity of electrical equipment at the end of the substation grid can lead to a prominent problem of reactive power imbalance. On the one hand, a large number of inductive loads such as motors and transformers consume a large amount of reactive power during operation, which reduces the power factor of the grid, increases line loss and voltage drop, and affects power quality and power supply reliability. On the other hand, the intermittent and volatile output of distributed power sources such as photovoltaic and wind power at the end of the substation grid further exacerbates the imbalance of reactive power.

[0061] To determine the reactive power state at the end of the substation grid, a specific disturbance signal is usually injected into the substation, and the electrical response of the substation after injecting the disturbance signal is monitored and analyzed to achieve the determination.

[0062] In the prior art, the patent document with the application publication number CN120527947A provides a control method and system for improving the generation accuracy of SVG disturbance signals. The technical solution is to calculate the attenuation of the disturbance signal caused by SVG direct current voltage control through an observer, superimpose the phase compensation after the direct current voltage given value as the input of the outer ring of the voltage controller, and subtract the direct current voltage feedback to obtain the outer ring output through the voltage controller of the outer ring and superimpose it with the command current disturbance signal as the input of the current controller of the inner ring, and control the operation of SVG through the current inner ring controller and PWM modulation command. The influence of the direct current voltage outer ring on the actual current disturbance signal is significantly reduced, so that the SVG can still output accurate actual current disturbance signals when injecting each frequency command current disturbance signal.

[0063] However, the SVG disturbance signal described above is injected into the d-axis component and the q-axis component respectively through the dq-axis decoupling control algorithm, and is converted into a three-phase signal after PI closed-loop control and inverse transformation, and is converted into a PWM signal for control. It is suitable for three-phase balanced occasions. For the three-phase unbalanced situation often existing at the end of the transformer area power grid, the dq-axis decoupling control algorithm is difficult to accurately control the three-phase voltage and current, resulting in that the injected disturbance signal cannot accurately reflect the actual voltage condition, thereby affecting the accurate judgment of the reactive power state at the end of the transformer area power grid.

[0064] Moreover, the method has poor adaptability when facing complex power consumption environment at the end of the transformer area power grid and a large number of distributed power access, and can not respond to the change of the reactive power at the end of the transformer area power grid in time, resulting in that the reactive power compensation is not timely or inaccurate.

[0065] In view of the above problems, the purpose of the present application is to provide a method and device which can effectively solve the problem of accurate judgment of reactive power state under three-phase unbalanced condition at the end of the transformer area power grid, and can respond to the change of the reactive power at the end of the transformer area power grid in time and perform reactive power compensation in time.

[0066] The present application provides a transformer area power grid end reactive power compensation method, and the specific technical scheme is as follows:

[0067] The sampling module measures The voltage of the point of common coupling of the transformer area power grid end power grid at the moment ;

[0068] The point of common coupling is selected as close to the load side of the transformer area power grid end as possible, so that the actual situation of the end voltage can be more accurately reflected. When selecting the point of common coupling, multiple factors need to be considered comprehensively, such as the geographical distribution of the transformer area, the load type and distribution density, etc. For the transformer area with a larger geographical range, the point of common coupling can be selected in each region according to the load characteristics of different regions, so as to ensure that the end voltage of the entire transformer area can be monitored comprehensively. At the same time, the point of common coupling should be selected at a position which is easy to measure and maintain, and should be avoided to be selected at a strong electromagnetic interference area or a place with safety hidden danger.

[0069] The impedance calculation unit obtains The load end impedance at the moment ;

[0070] The load end impedance at the moment This can be calculated by comprehensively analyzing information such as historical load operating data. Firstly, by analyzing long-term load operating data, we can understand the impedance variation patterns of the load under different time periods and operating conditions. For example, for some industrial loads, their impedance values ​​will differ significantly between peak and off-peak production periods. By modeling this historical data, we can obtain a mathematical model of how the load impedance changes with time and operating conditions.

[0071] The reactive power calculation unit passes through The voltage at the common coupling point at time [time] and Constant load impedance calculate The reactive power required to be compensated at the common coupling point at time [time]. , The reactive power required to be compensated at the common coupling point at time [time]. ;

[0072] The current command generation unit generates the current command based on the reactive power. Calculate the target compensation current that needs to be output and generate the target compensation current command;

[0073] The PWM unit generates a corresponding PWM control signal based on the target compensation current command to control the IGBT module to output compensation current to the common coupling point.

[0074] Time Inputting the input will allow you to roughly estimate the load impedance at this point. .

[0075] For example, analyzing the operating data of a certain transformer substation over the past year reveals that its impedance value remains relatively stable during daytime production hours, while it rises significantly during nighttime rest periods. Using this data, a linear model of impedance variation over time is established, where a specific time interval is input. At that time, the load impedance can be estimated based on this model. .

[0076] pass The voltage at the common coupling point at time [time] and Constant load impedance calculate Common coupling point load current The Common coupling point load current ;

[0077] pass The voltage at the common coupling point at time [time] and Constant load impedance computing reactive power at the point of common coupling at the moment.

[0078] In these embodiments, the load current and the reactive power at the point of common coupling at different moments can be accurately obtained through calculation, thereby providing a solid data foundation for accurately judging the reactive power state at the end of the transformer area power grid.

[0079] According to the calculated reactive power, the size of the reactive power required to be compensated by the point of common coupling can be determined, so that the current instruction generation unit can calculate the target compensation current required to be output and generate a target compensation current instruction.

[0080] The PWM unit generates a PWM control signal according to the target compensation current instruction, accurately controls the IGBT module to work, and outputs appropriate compensation current to the point of common coupling. The reactive power at the end of the transformer area power grid can be effectively adjusted, the power factor of the power grid can be improved, the line loss and voltage drop can be reduced, and the power quality and power supply reliability can be improved.

[0081] In some embodiments, in order to more accurately obtain the load end impedance at the moment , the load end impedance at the moment is obtained, including the following steps:

[0082] The sampling module measures the voltage of the point of common coupling at the moment ;

[0083] The disturbance generation unit injects a current disturbance into the point of common coupling at the moment ;

[0084] The impedance calculation unit sets a sampling period, measures the voltage of the point of common coupling at the moment under the action of the disturbance signal , calculates the voltage change , calculates the load end impedance at the moment according to the voltage change and the current disturbance , and the load end impedance at the moment .

[0085] ​​​​In these embodiments, the load-side impedance calculated using this method more closely reflects actual operating conditions and has higher accuracy. This is because in a real-world distribution network, load characteristics constantly change with time, environment, and other factors. By injecting random current disturbance signals and measuring voltage changes to calculate impedance, these changes can be captured in real time, resulting in a more accurate load-side impedance value at the current moment. Based on this accurate load-side impedance value, the subsequent calculation of the required reactive power compensation at the end of the distribution network will also be more accurate, further improving the accuracy and reliability of the entire reactive power compensation system.

[0086] like Figure 3 As shown, a current disturbance signal is injected at the common coupling point. Afterwards, when it is necessary to obtain When measuring the voltage change at a given time, it is necessary to measure... Voltage at time and Voltage at time The voltage change is obtained by subtracting the two. In the calculation Voltage change at time Then, through current disturbance signal and Voltage change at time Then, it can be done through the formula Calculate Constant load impedance .

[0087] After obtaining Constant load impedance Then, you can use the formula described above. ;calculate Reactive power required to compensate at the point of common coupling at any given time Subsequently, the current command generation unit can use this reactive power as a basis. The system accurately calculates the target compensation current to be output and generates a target compensation current command. Based on this command, the PWM unit generates a corresponding PWM control signal to precisely control the IGBT module to output the compensation current to the point of common coupling, thereby effectively regulating the reactive power at the end of the distribution network.

[0088] In actual operation, the load conditions in the transformer area are constantly changing, such as residential users turning on or off electrical appliances, and industrial users adjusting their production plans, all of which will cause changes in the load current.

[0089] Therefore, in some embodiments, to ensure accurate load-side impedance, the sampling period includes a continuous sampling period. T and intermittent sampling period t, the continuous sampling period T and the intermittent sampling period t satisfies T = n t, where n is a positive integer greater than 1;

[0090] the continuous sampling period T and the intermittent sampling period t have the same sampling frequency;

[0091] For example, assuming that the continuous sampling period ΔT is 10S, the intermittent sampling period Δt is 2S, and n = 5. Within the continuous sampling period ΔT, the system samples the voltage at the point of common coupling and the relevant data at the load end according to a fixed sampling frequency. The intermittent sampling period Δt is intermittently operated, and every 5 intermittent sampling periods Δt, that is, the duration of one continuous sampling period ΔT, the sampling work of the intermittent sampling period Δt is started again.

[0092] Within the continuous sampling period ΔT, the sampling module continuously measures the voltage at the point of common coupling and other data, providing basic data for subsequent calculation of the impedance and reactive power at the load end. When the intermittent sampling period Δt is working, it is used to verify the sampling data within the continuous sampling period ΔT.

[0093] When the continuous sampling period ΔT and the intermittent sampling period Δt work together, they can better adapt to the dynamic changes of the load in the transformer area.

[0094] the intermittent sampling period t collects data for verifying the data collected by the continuous sampling period T:

[0095] When the data collected within the intermittent sampling period t and the data collected within the continuous sampling period are within a preset range, the continuous sampling period T is determined to be an effective sampling period;

[0096] When the data collected within the intermittent sampling period and the data collected within the continuous sampling period exceed the preset range, the continuous sampling period is shortened to Δ , and the sampling is restarted with the shortened continuous sampling period Δ , and the data collected by the intermittent sampling period t is compared again;

[0097] If the newly collected data and the data collected by the intermittent sampling period t still deviate beyond the preset range, the continuous sampling period is further shortened, and the above re-sampling and comparison process is repeated until it is shortened to newly collected data of the continuous sampling period and the intermittent sampling period deviation of the data collected by the continuous sampling period and the intermittent sampling period is within a preset range, the sampling period sampling as an effective continuous sampling period.

[0098] For example, assume that the continuous sampling period AT is set to 10S and the intermittent sampling period At is set to 2S, and n = 5, when the power grid in a certain area is running normally. In a sampling process, the load end impedance data collected by the continuous sampling period AT shows a relatively stable trend, while the data collected by the intermittent sampling period At deviates from the data of the continuous sampling period beyond the preset range. This may be due to the sudden start-up of large industrial equipment in the area within 2S, resulting in a large change in the load condition.

[0099] At this time, according to the above method, the continuous sampling period is shortened to AT1 = 5S for resampling. After comparing the data collected by the intermittent sampling period At again, it is found that the deviation is still beyond the preset range. This indicates that the load changes frequently and greatly, and the continuous sampling period needs to be shortened further. Therefore, the continuous sampling period is continuously shortened to AT2 = 2S, resampling is performed, and the data collected by the intermittent sampling period At is compared. At this time, the deviation is within the preset range, so the sampling period AT2 is taken as the effective continuous sampling period for subsequent sampling work.

[0100] Through this way of dynamically adjusting the continuous sampling period, the rapid changes of the load in the area can be timely adapted to, and accurate load end impedance data can be obtained. Based on the accurate load end impedance, the required reactive power compensation at the public coupling point of the power grid in the area can be accurately calculated, and then the current command generation unit generates accurate target compensation current commands, and the PWM unit generates appropriate PWM control signals according to the commands to control the IGBT module to output accurate compensation current to the public coupling point.

[0101] This adaptive sampling period adjustment method can also better cope with the complex and changeable power environment in the area, and improve the flexibility and adaptability of the reactive power compensation system.

[0102] After injecting the current disturbance signal ΔI, due to the complexity of the load characteristics, the voltage change may have fluctuations on different time scales. A longer continuous sampling period can filter out some short-term and random voltage fluctuations, and more clearly show the macroscopic change trend of the voltage over time, which is very helpful for analyzing the long-term characteristics and overall change law of the load. A shorter intermittent sampling period can timely capture those instantaneous and rapid voltage changes, such as voltage mutations caused by the sudden start or stop of some load equipment.

[0103] Through this multi-scale sampling mode, the changes of the load end impedance can be more comprehensively and meticulously monitored. For example, in some special cases, the load end may have a sharp fluctuation in a short time, such as the sudden start or stop of a large equipment. At this time, the intermittent sampling period can timely capture such rapid changes and record the instantaneous fluctuation of the voltage. For the long-term change trend of the load end impedance, such as the slow change of the load characteristics caused by factors such as seasonal changes and user electricity use habits, the continuous sampling period can provide accurate information.

[0104] In some embodiments, as shown in FIG. 1, a disturbance generation unit suitable for the end of a three-phase unbalanced transformer area power grid is provided, which includes a first disturbance generation circuit, the first disturbance generation circuit includes a phase-locked loop circuit, a voltage control circuit, a disturbance injection circuit and a current control circuit, Figure 4

[0105] The phase-locked loop circuit includes a phase-locked loop PLL, and the phase-locked loop circuit is configured to phase-lock the common coupling point voltage to obtain a grid phase angle ;

[0106] The disturbance injection circuit includes a disturbance signal giving module, and the disturbance injection circuit is configured to generate disturbance current given instructions , disturbance current given instructions and disturbance current given instructions with reference to the real-time grid phase angle θ.

[0107] The voltage control circuit includes a first subtractor, a first PI controller and an inverse PARK transformation module, and the voltage control circuit is configured to generate voltage fluctuations , voltage fluctuations and voltage fluctuations in response to the disturbance current given instructions , disturbance current given instructions and disturbance current given instructions , the voltage fluctuations are calculated according to the DC side voltage reference value input to the first subtractor and the actually measured DC side voltage , the voltage fluctuations are adjusted by the first PI controller, and the outer loop output current instructions , outer loop output current instructions and outer loop output current instructions

[0108] are obtained by the inverse PARK transformation. ​The outer loop output current command and the disturbance current given command The outer loop output current command and the disturbance current given command The intermediate disturbance current given command The intermediate disturbance current given command and the intermediate disturbance current given command

[0109] The intermediate disturbance current given command and the three-phase current in the terminal grid of the transformer area The disturbance current The intermediate disturbance current given command and the three-phase current in the terminal grid of the transformer area The disturbance current The intermediate disturbance current given command and the three-phase current in the terminal grid of the transformer area The disturbance current

[0110] The disturbance current The disturbance current and the disturbance current are respectively input to the first PR controller, the second PR controller and the third PR controller for adjustment and then converted into disturbance voltages The disturbance voltage and the disturbance voltage

[0111] The disturbance voltage and the voltage of the terminal grid of the transformer area The disturbance voltage and the voltage of the terminal grid of the transformer area The disturbance voltage and the voltage of the terminal grid of the transformer area The disturbance voltage

[0112] In the embodiment, the phase-locked loop circuit in the first disturbance generation circuit performs phase locking on the PCC voltage, obtains the grid phase angle, and provides an accurate phase reference for the subsequent generation of the disturbance current given command. This enables the injection of the disturbance current to match the real-time phase of the grid, thereby improving the effectiveness and pertinence of the disturbance signal.

[0113] ​​​The disturbance injection circuit generates a disturbance current command according to the real-time phase angle of the power grid. The disturbance current command can be dynamically adjusted according to the actual operating state of the power grid. Under different phases, the load characteristics may be different. By generating a command according to the real-time phase angle, the disturbance current can better adapt to the changes in the power grid, thereby more accurately reflecting the impedance at the load end.

[0114] The voltage control circuit compares the DC side voltage reference value with the actual measured value, generates a voltage fluctuation, and obtains an outer loop output current command through a PI controller and an inverse PARK transformation. This closed-loop control method can effectively stabilize the DC side voltage and ensure stable operation of the system.

[0115] After obtaining the disturbance current, the PR controller converts it into a disturbance voltage and superimposes it with the voltage at the end of the transformer area power grid to finally generate a first disturbance current control signal. The PR controller has good harmonic suppression capability and can effectively reduce the harmonic components in the disturbance signal, improving the quality of the disturbance signal. The superimposed disturbance current control signal can more accurately reflect the actual situation at the load end, providing more reliable data for subsequent calculation of the load end impedance and reactive power.

[0116] The design of this first disturbance generation circuit not only considers the real-time phase of the power grid and the changes in load characteristics, but also improves the accuracy and stability of the disturbance signal through multiple control links and algorithms. It can effectively deal with the complex situation at the end of the three-phase unbalanced transformer area power grid, providing strong support for accurately obtaining the load end impedance and achieving precise reactive power compensation.

[0117] In some embodiments, for three-phase balanced conditions, as shown in Figure 5 The disturbance generation unit further comprises:

[0118] A second disturbance generation circuit, the second disturbance generation circuit comprising a PARK transformation module that receives the disturbance current command , the disturbance current command and the disturbance current command and converts them into d-axis disturbance current commands and q-axis disturbance current commands in a two-phase rotating coordinate system;

[0119] The d-axis disturbance current command and the q-axis disturbance current command are compared with the d-axis actual current and the q-axis actual current respectively to obtain the d-axis current deviation and the q-axis current deviation;

[0120] The d-axis current deviation and the q-axis current deviation are input into a second PI controller and a third PI controller respectively to obtain a d-axis adjustment and a q-axis adjustment;

[0121] The d-axis actual current and the q-axis actual current are decoupled by the real-time phase angle θ of the power grid to obtain a decoupled d-axis current and a decoupled q-axis current;

[0122] The decoupled d-axis current and the decoupled q-axis current are added to the d-axis adjustment and the q-axis adjustment respectively to obtain a d-axis control and a q-axis control;

[0123] The d-axis control and the q-axis control are superimposed with a d-axis adjustment voltage and a q-axis adjustment voltage to obtain a second disturbance current control signal.

[0124] In these embodiments, the second disturbance generation circuit performs PArk transformation on the disturbance current instruction under three-phase balanced conditions, converts the instruction in the three-phase coordinate system into d-axis and q-axis instructions in the two-phase rotating coordinate system, and such transformation can simplify the analysis and control of the three-phase balanced system. By comparing the actual current with the instruction current in the d-axis and the q-axis, the current deviation is obtained, and then the PI controller is adjusted to effectively eliminate the current deviation and make the output of the system closer to the instruction value.

[0125] The decoupled d-axis current and the decoupled q-axis current are added to the d-axis adjustment and the q-axis adjustment respectively to obtain a d-axis control and a q-axis control;

[0126] In some embodiments, as shown in Figure 6 , in order to make the generated second disturbance current control signal more accurate, the second disturbance generation circuit further includes a disturbance compensation module, which receives the d-axis disturbance current instruction and the q-axis disturbance current instruction output by the PARK transformation module, compensates the d-axis disturbance current instruction and the q-axis disturbance current instruction to generate a d-axis compensation voltage and a q-axis compensation voltage, and inputs the d-axis compensation voltage and the q-axis compensation voltage after superimposed with the voltage fluctuation to the first PI controller.

[0127] By setting the disturbance compensation module to compensate the d-axis and q-axis disturbance current instructions and generate compensation voltages, and then superimposing them with the voltage fluctuations before inputting them into the first PI controller, the control effect of the system can be further optimized. Under the condition of three-phase balance, the operation state of the power grid is relatively stable, but there may still be some minor fluctuations and interference factors. The disturbance compensation module can compensate for these potential influencing factors in advance, reducing the error and fluctuations of the system. By superimposing the d-axis compensation voltage and q-axis compensation voltage generated by compensation with the voltage fluctuations, the signals input into the first PI controller can more accurately reflect the actual situation of the system, so that the first PI controller can adjust more accurately.

[0128] In order to save resources, in some embodiments, when the sampling period As an effective sampling period, after the sampling time T is continuously performed, the continuous sampling period is restored to the initial set value T;

[0129] The intermittent sampling period t is used again to test the data collected by the continuous sampling period

[0130] By this way of restoring the continuous sampling period and retesting, the resources can be reasonably used while ensuring the accurate acquisition of the load end impedance data. After a certain time T of continuous sampling at a short sampling period

[0131] The data collected by the continuous sampling period

[0132] This periodic restoration and testing mechanism makes the reactive power compensation system find a good balance between resource utilization and data accuracy. It can flexibly adjust the sampling period according to the actual changes of the load in the transformer area, avoid wasting resources caused by long-term use of short sampling period, and timely discover the load changes and take corresponding adjustment measures, further improve the overall performance and adaptability of the reactive power compensation system, and ensure accurate reactive power compensation in different power consumption environments, improve the operation efficiency and power quality of the transformer area power grid.

[0133] In some embodiments, a method is provided for The load end impedance The acquisition method of the load end impedance The load end impedance is estimated by historical load data through data fitting and prediction models, specifically including:

[0134] Collecting load-related data of the substation area in the past period of time, including voltage, current values at different time points, etc. to construct a historical data set;

[0135] Training and learning the historical data set using data fitting and prediction models, so that the prediction model masters the change law and characteristics of the load end impedance over time t;

[0136] Inputting the current time information and known partial load data into the trained model to estimate the load end impedance at the current moment .

[0137] This estimation method is suitable for substation areas with relatively stable load changes and certain historical data accumulation. In these substation areas, the change of the load end impedance often has certain regularity, and through the mining and analysis of historical data, a relatively accurate data fitting and prediction model can be established. For example, in a residential substation area, the electricity consumption habits of residents usually have certain periodicity, and the electricity consumption peaks and troughs in the daytime and evening are relatively fixed, and the seasonal electricity consumption difference is also relatively stable. The model constructed using these historical electricity consumption data can better predict the load end impedance in different time periods.

[0138] However, this method of estimating the load end impedance based on historical data also has certain limitations. When new large-scale load equipment is put into use in the substation area, part of the load equipment is updated, or the electricity consumption policy is adjusted significantly, etc., the load characteristics may change fundamentally, and the original data fitting and prediction model may not be able to adapt to such changes in time, resulting in inaccurate estimation results. At this time, it is necessary to combine the method of injecting random current disturbance signals mentioned earlier to recalculate and calibrate the load end impedance, so as to ensure the effect of the reactive power compensation method.

[0139] In actual application, the method of estimating the load end impedance based on historical data and the method of injecting random current disturbance signals can be combined. In the period of relatively stable load characteristics, the estimation method based on historical data is preferred to reduce the calculation amount and consumption of system resources; while at the key nodes where the load characteristics may change or when abnormal fluctuations of the load are monitored, the method of injecting random current disturbance signals is switched in time to accurately obtain the real-time change of the load end impedance. In this way, both the calculation efficiency and the accuracy and stability of voltage regulation can be ensured.

[0140] In some embodiments, the first disturbance generation circuit and the second disturbance generation circuit are controlled by a three-phase balance judgment module, which monitors the three-phase voltage of the common coupling point, judges whether the common coupling point meets the three-phase balance condition, and sends different control instructions to the first disturbance generation circuit and the second disturbance generation circuit according to the degree and type of imbalance:

[0141] When the common coupling point is three-phase unbalanced, the three-phase balance judgment module controls the first disturbance generation circuit to work, calculates the reactive power at the end of the transformer area power grid through the first current disturbance signal, generates a compensation current, and makes the end of the transformer area power grid reach three-phase balance.

[0142] When the common coupling point is three-phase balanced, the three-phase balance judgment module controls the second disturbance generation circuit to work, and uses the second disturbance current signal to analyze the stability of the end of the transformer area power grid.

[0143] By setting the three-phase balance judgment module, the working state of the first disturbance generation circuit and the second disturbance generation circuit can be automatically and flexibly switched according to the actual three-phase voltage of the common coupling point. When three-phase is unbalanced, the first disturbance generation circuit is put into work, and the first current disturbance signal generated by it plays a key role in reactive power calculation. By accurately calculating the reactive power, a suitable compensation current is generated to effectively compensate the reactive power at the end of the transformer area power grid. This compensation can improve the three-phase unbalanced condition, make the end of the transformer area power grid gradually reach three-phase balance, reduce various power losses and equipment damage risks caused by three-phase imbalance, and improve the operation efficiency and safety of the power grid.

[0144] When three-phase is balanced, the second disturbance generation circuit starts to work. The second disturbance current signal is used to analyze the stability of the end of the transformer area power grid. In the state of three-phase balance, although the power grid is relatively stable, it may still be affected by various factors and appear potential instability. The signal generated by the second disturbance generation circuit can simulate some possible disturbance conditions, analyze the response of the power grid under these disturbances, and evaluate the stability of the power grid. This helps to discover potential problems in the power grid in advance, take appropriate measures for optimization and improvement in time, and further ensure the stable operation of the transformer area power grid.

[0145] In some embodiments, the present application provides a transformer area power grid end reactive power compensation device, which comprises at least one processor and a memory, and the memory stores instructions which, when executed by the at least one processor, implement the steps of the method according to any one of the above embodiments.

[0146] While this specification contains many specifics, these should not be construed as limitations on the scope of any invention, or that which can be claimed, but rather as descriptors of particular implementations thereof. Accordingly, the scope of the application should be determined not by the specifics in this specification, but by the appended claims and their equivalents. Certain features that are described in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented separately or in any suitable subcombination. Moreover, although features can be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination and the claimed combination can be directed to a subcombination or variation of a subcombination.

[0147] Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring such order nor that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing can be advantageous. Moreover, the separation of various system modules and components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the program components and systems can typically be integrated in a single software product or packaged into multiple software products.

Claims

1. A method for reactive power compensation at the end of a distribution network, characterized in that, The method includes the following steps: Sampling module measurement Voltage at the common coupling point of the power grid at the time of the distribution area ; The disturbance generation unit in Time and Injecting current disturbances into the common coupling point at intervals ; Impedance calculation unit obtains Constant load impedance ; The reactive power calculation unit is based on the above. Voltage at the common coupling point of the power grid at the time of the distribution area and stated Constant load impedance calculate Reactive power compensation required at the end of the power grid at any time ,in ; The current command generation unit generates the current command based on the reactive power compensation. Calculate the target compensation current required for output. Generate the target compensation current command, where ; The PWM unit generates a compensation current control signal according to the target compensation current command; The IGBT outputs to the common coupling point according to the compensation current control signal. Compensation current at the end of the power grid in the time zone ; The disturbance generation unit includes a first disturbance generation circuit, which comprises a phase-locked loop circuit, a voltage control circuit, a disturbance injection circuit, and a current control circuit. The disturbance generation unit also includes a second disturbance generation circuit, which comprises a PARK converter module and a disturbance compensation circuit. The first and second disturbance generation circuits are controlled by a three-phase balance judgment module. The three-phase balance judgment module monitors the three-phase voltage at the common coupling point and determines whether the common coupling point meets the three-phase balance condition. The three-phase balance judgment module issues different control commands to the first and second disturbance generation circuits based on the degree and type of imbalance. When the three phases at the common coupling point are unbalanced, the three-phase balance judgment module controls the first disturbance generation circuit to generate a first disturbance current to regulate the end of the power grid in the distribution area in order to restore the balance of the three-phase voltage. When the three phases at the common coupling point are in balance, the three-phase balance judgment module controls the second disturbance generation circuit to generate a second disturbance current to perform stability analysis on the end of the power grid in the distribution area.

2. The reactive power compensation method at the end of a distribution network as described in claim 1, characterized in that, The method further includes the following steps: The sampling module is set with a sampling period and also measures... Voltage at the common coupling point of the power grid at the time of the distribution area ; The impedance calculation unit first calculates Voltage change at the common coupling point at the end of the power grid in the time zone ,in - ; then calculate Constant load impedance ,in .

3. The reactive power compensation method at the end of the distribution network as described in claim 2, characterized in that, The sampling period includes a continuous sampling period. T and intermittent sampling period t, the intermittent sampling period t is set in the continuous sampling period Within T, the intermittent sampling period t is less than the continuous sampling period T; The continuous sampling period T and the intermittent sampling period The sampling frequency of t is the same; When the intermittent sampling period The data collected within t and the continuous sampling period When the deviation of the data collected within T is within a preset range, the continuous sampling period is determined. T is the effective sampling period; When the intermittent sampling period The data collected within t and the continuous sampling period When the deviation of the data collected within T exceeds the preset range, the continuous sampling period is shortened. T is obtained after the shortened continuous sampling period ∆ With the shortened continuous sampling period ∆ Resample, and again with the intermittent sampling period. The collected data is compared.

4. The reactive power compensation method at the end of the distribution network as described in claim 3, characterized in that, When the shortened continuous sampling period ∆ The collected data and the intermittent sampling period If the deviation of the collected data still exceeds the preset range, the continuous sampling period is further shortened. T is obtained after further shortening the continuous sampling period With the further shortened continuous sampling period Resample, and again with the intermittent sampling period. The collected data is compared until the continuously shortened sampling period is reached. The collected data and the intermittent sampling period The collected data will be collected until the deviation is within the preset range.

5. The reactive power compensation method at the end of the distribution network as described in claim 2, characterized in that, The phase-locked loop circuit includes a phase-locked loop (PLL), and the PLL circuit receives the voltage at the common coupling point. Phase angle at the end of the power grid in the output area ; The voltage control circuit includes a first subtractor, a first PI controller, and an inverse PARK converter module. The voltage control circuit receives DC-side voltage. DC side reference voltage Phase angle at the end of the power grid in the distribution area Output current command for phase a outer loop b-phase outer loop output current command and c-phase outer loop output current command ; The disturbance injection circuit includes a disturbance signal input module, a second subtractor, a third subtractor, and a fourth subtractor. The disturbance injection circuit receives the phase angle at the end of the power grid in the distribution area. The outer loop output current command of phase a The b-phase outer loop output current command and the c-phase outer loop output current command Output the command for the intermediate disturbance current of phase a. b-phase intermediate disturbance current command Inter-phase disturbance current command ; The current control circuit includes a first PR controller, a second PR controller, a third PR controller, a fifth subtractor, a sixth subtractor, a seventh subtractor, a first adder, a second adder, and a third adder. The current control circuit receives the commanded intermediate disturbance current of phase a. The command for the intermediate disturbance current of phase b. The command for the intermediate disturbance current of phase c. Phase a current at the end of the distribution network Phase b current at the end of the distribution network c-phase current at the end of the distribution network Phase a voltage at the end of the distribution network Phase b voltage at the end of the distribution network c-phase voltage at the end of the distribution network Output the first disturbance current control signal.

6. The reactive power compensation method at the end of a distribution network as described in claim 5, characterized in that, The voltage control circuit is based on the DC-side reference voltage input to the first subtractor. and the DC side voltage Calculated voltage fluctuation The voltage fluctuation The outer loop output current command of phase a is obtained after adjustment by the first PI controller and transformation by the inverse PARK converter module. The b-phase outer loop output current command and the c-phase outer loop output current command ; The disturbance injection circuit commands the outer loop output current of phase a. and the perturbation current command for phase a The input to the second subtractor is used to obtain the command for the intermediate disturbance current of phase a. The b-phase outer loop output current command and phase b disturbance current given command The input to the third subtractor is used to obtain the command for the intermediate disturbance current of phase b. The c-phase outer loop output current command and the given command for the c-phase disturbance current The input to the fourth subtractor is used to obtain the command for the intermediate disturbance current of phase c. ; The current control circuit gives a command to the intermediate disturbance current of phase a. and the a-phase current at the end of the power grid in the aforementioned distribution area The input to the fifth subtractor yields the phase a disturbance current. The command is given to the intermediate disturbance current of phase b. and the b-phase current at the end of the power grid in the aforementioned distribution area The input to the sixth subtractor yields the phase b disturbance current. The command is given to the intermediate disturbance current of phase c. and the c-phase current at the end of the power grid in the aforementioned distribution area The c-phase disturbance current is obtained by inputting it into the seventh subtractor. ; The current control circuit will control the phase a disturbance current. The b-phase disturbance current and the c-phase disturbance current The voltage is input to the first PR controller, the second PR controller, and the third PR controller respectively, and then adjusted to convert it into phase a disturbance voltage. b-phase disturbance voltage and c-phase disturbance voltage ; The current control circuit will control the phase a disturbance voltage. and the phase a voltage at the end of the power grid in the aforementioned distribution area The input is given to the first adder to convert the b-phase disturbance voltage. and the b-phase voltage at the end of the power grid in the aforementioned distribution area The input is given to the second adder to convert the c-phase disturbance voltage. and the c-phase voltage at the end of the power grid in the aforementioned distribution area The signal is input to the third adder and superimposed to generate the first disturbance current control signal.

7. The reactive power compensation method at the end of a distribution network as described in claim 6, characterized in that, The PARK conversion module receives the command for the phase a disturbance current. The b-phase disturbance current command and the given command for the c-phase disturbance current This is then converted into a d-axis disturbance current command in a two-phase rotating coordinate system. and q-axis disturbance current command ; The disturbance compensation circuit includes an eighth subtractor, a ninth subtractor, a fourth and a fifth adder, a second PI controller, a third PI controller, a sixth adder, and a seventh adder. The disturbance compensation circuit receives the d-axis disturbance current command output by the PARK converter module. and the q-axis disturbance current command Output the second disturbance current control signal.

8. The reactive power compensation method at the end of a distribution network as described in claim 7, characterized in that, The disturbance compensation circuit will command the d-axis disturbance current. Output current command of the outer loop of the d-axis The input to the eighth subtractor yields the d-axis current deviation, which is then used to input the q-axis disturbance current command. and q-axis outer loop output current command The q-axis current deviation is obtained by inputting it into the ninth subtractor. The d-axis current deviation is compared with the actual d-axis current. The input is fed into the fourth adder to generate a superimposed d-axis current signal; The q-axis current deviation is compared with the actual q-axis current. The input is fed into the fifth adder to generate a superimposed q-axis current signal; The superimposed d-axis current signal and the superimposed q-axis current signal are respectively input to the second PI controller and the third PI controller for adjustment to obtain the d-axis adjustment amount and the q-axis adjustment amount; The actual current of the d-axis and q-axis actual current Decoupling is performed by the phase angle θ at the end of the power grid in the substation area to obtain the d-axis decoupling current and the q-axis decoupling current. The d-axis decoupling current and the d-axis adjustment amount are input to the sixth adder and superimposed to obtain the d-axis control amount; the q-axis decoupling current and the q-axis adjustment amount are input to the seventh adder and superimposed to obtain the q-axis control amount. The d-axis control quantity and the d-axis adjustment voltage The input is superimposed on the sixth adder to obtain the d-axis control voltage, and the q-axis control quantity is combined with the q-axis adjustment voltage. The inputs are superimposed on the seventh adder to obtain the q-axis control voltage, and the d-axis control voltage and the q-axis control voltage are used as the second disturbance current control signal.

9. A reactive power compensation device at the end of a distribution network, characterized in that, The apparatus includes at least one processor and a memory storing instructions that, when executed by the at least one processor, perform the steps of the method according to any one of claims 1-8.

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