Transformer electric energy quality control method and system

Abstract

The invention relates to the technical field of electric energy quality control, and discloses a transformer electric energy quality control method and system. The method comprises the steps of S1, demand analysis and system design; s2, installing and debugging; s3, monitoring and analyzing; s4, implementing a control strategy; s5, compensating and adjusting; s6, evaluating the effect; s7, reporting and recording; and S8, maintenance and management. According to the technical scheme, equipment failure rate, production loss and maintenance cost indexes are introduced to quantitatively analyze the target and demand of electric energy quality control, and the severity of the electric energy quality problem and the required scheme are evaluated through a comprehensive scoring mechanism, so that the electric energy quality problem which seriously affects the electric energy quality problem can be more accurately solved.

Description

Technical Field

[0001] The present invention relates to the technical field of power quality control, and in particular to a transformer power quality control method and system. Background Art

[0002] With the rapid development of new energy technologies, the architecture of the power system is undergoing a profound change. Against this background, the demand for electricity in high-end manufacturing industries such as modern optoelectronics and semiconductor chips is growing, and these industries have extremely high requirements for the stability and quality of electricity. In particular, for precision manufacturing processes, electronic information engineering and green manufacturing technologies, the reliability of the power system and the quality of power have become key factors.

[0003] In these fields, the proportion of power electronic equipment is increasing. These devices are extremely sensitive to voltage fluctuations, especially transient voltage problems such as voltage sag and flicker. A small change in voltage may cause the production process to be interrupted, affect product quality, and even cause significant economic losses. Therefore, these high-end manufacturing industries have stricter standards for power quality and higher requirements for the continuity and stability of power supply.

[0004] To meet these requirements, the power system must adopt more advanced power quality control methods to ensure the quality of power and the reliability of power supply. Summary of the invention

[0005] The present invention provides a transformer power quality control method and system, which can formulate different power quality control schemes according to different power systems, promptly solve power quality problems such as voltage sag and flicker, and ensure the continuity and stability of power supply.

[0006] The present invention provides a transformer power quality control method, comprising the following steps:

[0007] S1: Demand analysis and system design: Determine the goals and requirements of power quality control, and design a transformer power quality control system that meets the requirements;

[0008] S2: Installation and commissioning: Install transformers, unified power quality controllers, voltmeters, ammeters, power quality analyzers, and commission the power system to ensure that all equipment is working properly;

[0009] S3: Monitoring and analysis: Use voltmeters and ammeters to monitor the system voltage and current values. The power quality analyzer analyzes the power quality of the system in real time based on the monitoring data to identify power quality problems.

[0010] S4: Control strategy implementation: Based on the analysis results, formulate corresponding control strategies and apply the control strategies;

[0011] S5: Compensation and regulation: Compensate and regulate the power quality of the power system;

[0012] S6: Effect evaluation: Evaluate whether the effect of the control strategy after implementation has reached the expected goal. If the effect is not ideal, implement S3 for further analysis and adjustment;

[0013] S7: Report and record: record the process and results of power quality control, prepare power quality reports, and provide data support for future improvements;

[0014] S8: Maintenance and management: Regularly maintain and inspect power quality control equipment, and update and optimize control strategies to adapt to changes in power system operation.

[0015] Furthermore, the power quality analyzer described in S3 analyzes the monitoring data including the calculation of three-phase imbalance, power factor and harmonic distortion rate.

[0016] The three-phase unbalance degree ε is defined and calculated by the following formula:

[0017]

[0018] Among them I a ,I b ,I c They are the three-phase currents, which can be measured by an ammeter;

[0019] The harmonic distortion rate THD is defined and calculated by the following formula:

[0020]

[0021] Where V n is the nth order harmonic voltage, and V1 is the fundamental voltage.

[0022] The power factor PF is defined and calculated using the following formula:

[0023]

[0024] S=UI

[0025] Among them, P is active power, S is apparent power, T is cycle time, U is the effective value of voltage, I is the effective value of current, and U and I can be directly obtained by measuring the root mean square value of AC voltage and AC current through a voltmeter and an ammeter.

[0026] Furthermore, the determination of the goals and requirements of power quality control described in S1 includes an analysis of the impact of the current system power quality problems. The central controller calculates the equipment failure rate, maintenance cost, and production loss caused by the power quality problems to quantify the analysis for subsequent evaluation results. The larger the calculated result value, the deeper the impact, and the greater the demand for power quality control. The quantification steps are as follows:

[0027] Define the equipment failure rate R, and the calculation formula is as follows:

[0028]

[0029] Where N s is the number of failed devices, N Z is the total number of devices;

[0030] Definition of production loss L P , the calculation formula is as follows:

[0031] L P =(E 原 -E 损 )·V p

[0032] E 原 is the baseline production efficiency, E 损 is the efficiency decreased due to power issues, V p is the output value per unit time;

[0033] Define the maintenance cost C;

[0034] Define the system score under a single quality problem as A i , A i Calculated by:

[0035] A i =W i1 R i +W i2 C i +W i3 L Pi

[0036] Where R i , C i , L Pi Represent the equipment failure rate, maintenance cost and production loss under a single quality problem, respectively, and W i1 , W i2 , W i3 Represents R under a single quality problem i , C i , L Pi The weights they hold respectively;

[0037] Based on this definition, the system's comprehensive score for power quality issues is A.

[0038]

[0039] Where n is the number of sampled scenes, W i is the weight value of different quality issues in comprehensive consideration;

[0040] Furthermore, the weight W i , W i1 , W i2 , W i3 The weights are obtained by combining the CRITIC weight method and the AHP weight method; the AHP weight and the CRITIC weight are calculated according to the expert scores and the past data respectively; firstly, the initial weights of the indicators are calculated by the AHP and CRITIC weight methods respectively; then the combined weights are obtained by using the minimum relative information entropy principle.

[0041] Furthermore, the comprehensive score A of the power quality problems faced by the power system is divided into three levels from low to high: slight, general, and severe. Different power quality control targets are adopted according to the level of the calculated comprehensive score A, and the thresholds of the power quality control targets from slight to severe are gradually tightened; slight means that the threshold of slight impact is not exceeded and the power quality status is within an acceptable range; general means that the power quality status exceeds the threshold of slight impact but does not reach the severe impact; severe means that the power quality status has caused the threshold of severe impact.

[0042] Furthermore, step S5 uses a unified power quality controller to compensate and adjust the power problem. The left converter of the unified power quality controller is connected in series with the transformer in the main circuit, outputs a compensation voltage to compensate for the voltage change of the main circuit, and the right converter is directly connected in parallel with the main circuit to output a compensation current to compensate for the current in the main circuit.

[0043] When voltage drops and transients occur, the unified power quality controller dynamically provides compensation voltage through the series compensation unit to offset the voltage drops and transient disturbances in the power grid and ensure voltage stability at the load end;

[0044] When the voltage is distorted, the unified power quality controller generates a compensation voltage on the series transformer that is equal in magnitude and opposite in direction to the distorted voltage to offset the various distorted components in the voltage source;

[0045] When harmonics occur, the parallel compensation unit of the unified power quality controller detects and compensates for the harmonic currents generated by the load, ensuring that the grid current is close to a sinusoidal waveform;

[0046] When reactive power is present, the unified power quality controller provides reactive power compensation through parallel compensation units, improves the power factor, and reduces the impact of reactive power on the grid;

[0047] When the three phases are unbalanced, the unified power quality controller adjusts the three-phase current imbalance to ensure that the three-phase loads receive power in a balanced manner.

[0048] Furthermore, the control strategy in step S4 includes indirect control and direct control. The indirect control is to control the series converter into a non-sinusoidal voltage source to compensate for the fundamental voltage and harmonic voltage of the power grid, and to control the parallel converter into a non-sinusoidal current source to compensate for the reactive power and harmonic current of the load.

[0049] Direct control is to directly control the grid current and load voltage. The series converter is controlled as a sinusoidal current source to make the input current sinusoidal; the parallel converter is controlled as a sinusoidal voltage source to make the load voltage a standard sinusoidal value.

[0050] Select the appropriate control strategy according to the structure of steps S1 and S3. If there are multiple power quality problems in the system and there are high requirements for compensation accuracy, select an indirect control strategy; if the control system design is simple and needs to maintain a stable compensation effect, select a direct control strategy.

[0051] Furthermore, in step S3, the calculated three-phase imbalance, power factor and harmonic distortion rate are compared with the target thresholds of power quality control set in step S1. If the thresholds are exceeded, it indicates that there is a power quality problem in the power system.

[0052] A system using a transformer power quality control method as claimed in any one of claims 1 to 7, comprising an adjustment module, a monitoring module, a control module, a communication module, a feedback module, and a data storage module;

[0053] The adjustment module includes a transformer and a unified power quality controller, which performs power quality compensation and adjustment on the power system by adjusting voltage, current and phase to improve power quality;

[0054] The monitoring module includes a voltmeter, an ammeter, and a power quality analyzer to monitor and analyze power quality issues in the power system; the control module is used to control the output of the electronic power transformer in real time;

[0055] The communication module is used to transmit data in the power system to an external system and receive instructions from the external system;

[0056] The feedback module is used to evaluate the effect of the control strategy after implementation and to make feedback adjustments;

[0057] The data storage module is used to store various data in the power system and generate reports.

[0058] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of a transformer power quality control method according to any one of claims 1 to 7 when executing the computer program.

[0059] It can be seen from the above technical scheme that 1. Since the embodiment of the present invention adopts a voltmeter, an ammeter and a power quality analyzer, it can monitor the voltage value and current value of the system in real time and perform real-time analysis on the power quality, thus helping to timely discover power quality problems and provide data support for subsequent control strategies.

[0060] 2. Since the embodiment of the present invention adopts a combination of the CRITIC weighting method and the AHP weighting method when determining the weights of the goals and requirements of power quality control, it takes into account both expert experience and actual data, making the weight determination more accurate and scientific, and can therefore more comprehensively and accurately reflect the importance of each indicator in the evaluation system.

[0061] 3. Since the embodiment of the present invention formulates and applies corresponding control strategies based on the analysis results of the monitoring data, it can more effectively solve the power quality problem and improve the stability and reliability of the power system.

[0062] 4. Since the embodiment of the present invention introduces equipment failure rate, production loss, and maintenance cost indicators to quantitatively analyze the goals and requirements of power quality control, and evaluates the severity of power quality problems and the required solutions through a comprehensive scoring mechanism, it helps to more accurately solve serious power quality problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0064] Figure 1 The present invention is a flowchart of a transformer power quality control method. DETAILED DESCRIPTION

[0065] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0066] Example 1

[0067] See also Figure 1 ,A transformer power quality control method,,including the following steps:

[0068] S1: Demand analysis and system design: Determine the goals and requirements of power quality control, and design a transformer power quality control system that meets the requirements;

[0069] S2: Installation and commissioning: Install transformers, unified power quality controllers, voltmeters, ammeters, power quality analyzers, and commission the power system to ensure that all equipment is working properly;

[0070] S3: Monitoring and analysis: Use voltmeters and ammeters to monitor the system voltage and current values. The power quality analyzer analyzes the power quality of the system in real time based on the monitoring data to identify power quality problems.

[0071] S4: Control strategy implementation: Based on the analysis results, formulate corresponding control strategies and apply the control strategies;

[0072] S5: Compensation and regulation: Compensate and regulate the power quality of the power system;

[0073] S6: Effect evaluation: Evaluate whether the effect of the control strategy after implementation has reached the expected goal. If the effect is not ideal, implement S3 for further analysis and adjustment;

[0074] S7: Report and record: record the process and results of power quality control, prepare power quality reports, and provide data support for future improvements;

[0075] S8: Maintenance and management: Regularly maintain and inspect power quality control equipment, and update and optimize control strategies to adapt to changes in power system operation.

[0076] Embodiment 2

[0077] To determine the goals and requirements of power quality control in S1, it is necessary to first determine the aspects of power quality problems that are currently affected by quantitative analysis, then assign different weight values ​​according to the scenarios and aspects, and finally quantify and calculate the scores through the formula:

[0078] Determining the goals and requirements of power quality control as described in S1 includes analyzing the impact of the current system power quality problems. The central controller calculates the equipment failure rate, maintenance cost, and production loss caused by the power quality problems to quantify the analysis for subsequent evaluation results. The larger the calculated result value, the deeper the impact, and the greater the demand for power quality control. The quantification steps are as follows:

[0079] Define the equipment failure rate R, and the calculation formula is as follows:

[0080]

[0081] Where N s is the number of failed devices, N Z is the total number of devices;

[0082] Definition of production loss L P , the calculation formula is as follows:

[0083] L P =(E 原 -E 损 )·V p

[0084] E 原 is the baseline production efficiency, E 损 is the efficiency decreased due to power issues, V p is the output value per unit time;

[0085] Define the maintenance cost C;

[0086] Define the system score under a single quality problem as A i , A i Calculated by:

[0087] A i =W i1 R i +W i2 C i +W i3 L Pi

[0088] Where R i , C i , L Pi Represent the equipment failure rate, maintenance cost and production loss under a single quality problem, respectively, and W i1 , W i2 , W i3 Represents R under a single quality problem i , C i , L Pi The weights they hold respectively;

[0089] Based on this definition, the system's comprehensive score for power quality issues is A.

[0090]

[0091] Where n is the number of sampled scenes, W i is the weight value of different quality issues in comprehensive consideration;

[0092] Weight W i , W i1 , Wi2 , W i3 The weights are obtained by combining the CRITIC weight method and the AHP weight method; the AHP weight and the CRITIC weight are calculated based on the expert scores and the past data; the initial weights of the indicators are calculated by the AHP and CRITIC weight methods respectively; and then the combined weights are obtained by using the minimum relative information entropy principle;

[0093] The comprehensive score A of the power quality problems faced by the power system is divided into three levels from low to high: slight, general, and severe. Slight means that the power quality status does not exceed the threshold of slight impact, and the power quality status is within an acceptable range. General means that the power quality status exceeds the threshold of slight impact but does not reach the threshold of severe impact. Severe means that the power quality status has caused the threshold of severe impact.

[0094] Different power quality control targets are adopted according to the gear position of the calculated comprehensive score A, and the power quality control target thresholds are gradually tightened from mild to severe;

[0095] Finally, appropriate power quality control strategies are formulated according to different target thresholds.

[0096] Embodiment 3

[0097] S3 determines the power quality problem by analyzing the monitoring data with a power quality analyzer to calculate the three-phase unbalance, power factor and harmonic distortion rate, and compares the calculated three-phase unbalance, power factor and harmonic distortion rate with the target threshold of power quality control set in step S1. If the threshold is exceeded, it indicates that the power system has a power quality problem;

[0098] The calculation is as follows: Define the three-phase unbalance ε and calculate it using the following formula:

[0099]

[0100] Among them I a ,I b ,I c They are the three-phase currents, which can be measured by an ammeter;

[0101] The harmonic distortion rate THD is defined and calculated by the following formula:

[0102]

[0103] Where V n is the nth order harmonic voltage, and V1 is the fundamental voltage.

[0104] The power factor PF is defined and calculated using the following formula:

[0105]

[0106] S=UI

[0107] Among them, P is active power, S is apparent power, T is cycle time, U is the effective value of voltage, I is the effective value of current, and U and I can be directly obtained by measuring the root mean square value of AC voltage and AC current through a voltmeter and an ammeter.

[0108] Embodiment 4

[0109] The control strategy in step S4 includes indirect control and direct control. The indirect control is to control the series converter into a non-sinusoidal voltage source to compensate for the fundamental voltage and harmonic voltage of the power grid, and to control the parallel converter into a non-sinusoidal current source to compensate for the reactive power and harmonic current of the load.

[0110] Direct control is to directly control the grid current and load voltage. The series converter is controlled as a sinusoidal current source to make the input current sinusoidal; the parallel converter is controlled as a sinusoidal voltage source to make the load voltage a standard sinusoidal value.

[0111] Select the appropriate control strategy according to the structure of steps S1 and S3. If there are multiple power quality problems in the system and there are high requirements for compensation accuracy, select an indirect control strategy; if the control system design is simple and needs to maintain a stable compensation effect, select a direct control strategy.

[0112] Embodiment 5

[0113] Step S5 uses a unified power quality controller to compensate and adjust the power problem. The left converter of the unified power quality controller is connected in series with the transformer in the main circuit, outputs a compensation voltage to compensate for the voltage change of the main circuit, and the right converter is directly connected in parallel with the main circuit, outputs a compensation current to compensate for the current in the main circuit;

[0114] When voltage drops and transients occur, the unified power quality controller dynamically provides compensation voltage through the series compensation unit to offset the voltage drops and transient disturbances in the power grid and ensure voltage stability at the load end;

[0115] When the voltage is distorted, the unified power quality controller generates a compensation voltage on the series transformer that is equal in magnitude and opposite in direction to the distorted voltage to offset the various distorted components in the voltage source;

[0116] When harmonics occur, the parallel compensation unit of the unified power quality controller detects and compensates for the harmonic currents generated by the load, ensuring that the grid current is close to a sinusoidal waveform;

[0117] When reactive power is present, the unified power quality controller provides reactive power compensation through parallel compensation units, improves the power factor, and reduces the impact of reactive power on the grid;

[0118] When the three phases are unbalanced, the unified power quality controller adjusts the three-phase current imbalance to ensure that the three-phase loads receive power in a balanced manner.

[0119] Embodiment 6

[0120] A system for a transformer power quality control method is provided, comprising an adjustment module, a monitoring module, a control module, a communication module, a feedback module, and a data storage module;

[0121] The adjustment module includes a transformer and a unified power quality controller, which performs power quality compensation and adjustment on the power system by adjusting voltage, current and phase to improve power quality;

[0122] The monitoring module includes a voltmeter, an ammeter, and a power quality analyzer to monitor and analyze power quality issues in the power system; the control module is used to control the output of the electronic power transformer in real time;

[0123] The communication module is used to transmit data in the power system to an external system and receive instructions from the external system;

[0124] The feedback module is used to evaluate the effect of the control strategy after implementation and to make feedback adjustments;

[0125] The data storage module is used to store various data in the power system and generate reports.

[0126] It should be noted that, since the information interaction, execution process, etc. between the units in the above-mentioned devices and systems are based on the same concept as the embodiments of the method of the present invention, the specific contents can be found in the description of the embodiments of the method of the present invention and will not be repeated here.

[0127] Those skilled in the art will appreciate that all or part of the steps in the various methods of the above embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium.

[0128] The above is a detailed introduction to a transformer power quality control method and system provided by an embodiment of the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A transformer power quality control method, characterized in that: The following steps are involved: S1: Demand analysis and system design: Determine the goals and requirements of power quality control, and design a transformer power quality control system that meets the requirements; S2: Installation and commissioning: Install transformers, unified power quality controllers, voltmeters, ammeters, power quality analyzers, and commission the power system to ensure that all equipment is working properly; S3: Monitoring and analysis: Use voltmeters and ammeters to monitor the system voltage and current values. The power quality analyzer analyzes the power quality of the system in real time based on the monitoring data to identify power quality problems. S4: Control strategy implementation: Based on the analysis results, formulate corresponding control strategies and apply the control strategies; S5: Compensation and regulation: Compensate and regulate the power quality of the power system; S6: Effect evaluation: Evaluate whether the effect of the control strategy after implementation has reached the expected goal. If the effect is not ideal, implement S3 for further analysis and adjustment; S7: Report and record: record the process and results of power quality control, prepare power quality reports, and provide data support for future improvements; S8: Maintenance and management: Regularly maintain and inspect power quality control equipment, and update and optimize control strategies to adapt to changes in power system operation.

2. A transformer power quality control method according to claim 1, characterized in that: The power quality analyzer described in S3 analyzes and monitors the data including the calculation of three-phase unbalance, power factor and harmonic distortion rate. The three-phase unbalance degree ε is defined and calculated by the following formula: Among them I a ,I b ,I c They are the three-phase currents, which can be measured by an ammeter; The harmonic distortion rate THD is defined and calculated by the following formula: Where V n is the nth order harmonic voltage, and V1 is the fundamental voltage. The power factor PF is defined and calculated using the following formula: SUI Among them, P is active power, S is apparent power, T is cycle time, U is the effective value of voltage, I is the effective value of current, and U and I can be directly obtained by measuring the root mean square value of AC voltage and AC current through a voltmeter and an ammeter.

3. A transformer power quality control method according to claim 1, characterized in that: Determining the goals and requirements of power quality control as described in S1 includes analyzing the impact of the current system power quality problems. The central controller calculates the equipment failure rate, maintenance cost, and production loss caused by the power quality problems to quantify the analysis for subsequent evaluation results. The larger the calculated result value, the deeper the impact, and the greater the demand for power quality control. The quantification steps are as follows: Define the equipment failure rate R, and the calculation formula is as follows: Where N s is the number of failed devices, N Z is the total number of devices; Definition of production loss L P , the calculation formula is as follows: L P =(E 原 -E 损 )·V p E 原 is the baseline production efficiency, E 损 It is the efficiency decreased due to the power problem, Vp is the output value per unit time; Define the maintenance cost C; Define the system score under a single quality problem as A i , A i Calculated by: A i =W i1 R i +W i2 C i +W i3 L Pi Where R i , C i , L Pi Represent the equipment failure rate, maintenance cost and production loss under a single quality problem, respectively, and W i1 , W i2 , W i3 Represents R under a single quality problem i , C i , L Pi The weights they hold respectively; Based on this definition, the system's comprehensive score for power quality issues is A. Where n is the number of sampled scenes, W i It is the weight value of different quality issues in comprehensive consideration.

4. A transformer power quality control method according to claim 4, characterized in that: Weight W i , W i1 , W i2 , W i3 The weights are obtained by combining the CRITIC weight method and the AHP weight method; the AHP weight and the CRITIC weight are calculated according to the expert scores and the past data respectively; firstly, the initial weights of the indicators are calculated by the AHP and CRITIC weight methods respectively; then the combined weights are obtained by using the minimum relative information entropy principle.

5. A transformer power quality control method according to claim 4, characterized in that: The comprehensive score A of the power quality problems faced by the power system is divided into three levels from low to high: slight, general, and severe. Different power quality control targets are adopted according to the level of the calculated comprehensive score A, and the thresholds of power quality control targets from slight to severe are gradually tightened; slight means that the threshold of slight impact is not exceeded, and the power quality status is within an acceptable range; general means that the power quality status exceeds the threshold of slight impact but does not reach the severe impact; severe means that the power quality status has caused the threshold of severe impact.

6. A transformer power quality control method according to claim 1, characterized in that: Step S5 uses a unified power quality controller to compensate and adjust the power problem. The left converter of the unified power quality controller is connected in series with the transformer in the main circuit, outputs a compensation voltage to compensate for the voltage change of the main circuit, and the right converter is directly connected in parallel with the main circuit, outputs a compensation current to compensate for the current in the main circuit; When voltage drops and transients occur, the unified power quality controller dynamically provides compensation voltage through the series compensation unit to offset the voltage drops and transient disturbances in the power grid and ensure voltage stability at the load end; When the voltage is distorted, the unified power quality controller generates a compensation voltage on the series transformer that is equal in magnitude and opposite in direction to the distorted voltage to offset the various distorted components in the voltage source; When harmonics occur, the parallel compensation unit of the unified power quality controller detects and compensates for the harmonic currents generated by the load, ensuring that the grid current is close to a sinusoidal waveform; When reactive power is present, the unified power quality controller provides reactive power compensation through parallel compensation units, improves the power factor, and reduces the impact of reactive power on the grid; When the three phases are unbalanced, the unified power quality controller adjusts the three-phase current imbalance to ensure that the three-phase loads receive power in a balanced manner.

7. A transformer power quality control method according to claim 1, characterized in that: The control strategy in step S4 includes indirect control and direct control. The indirect control is to control the series converter into a non-sinusoidal voltage source to compensate for the fundamental voltage and harmonic voltage of the power grid, and to control the parallel converter into a non-sinusoidal current source to compensate for the reactive power and harmonic current of the load. Direct control is to directly control the grid current and load voltage. The series converter is controlled as a sinusoidal current source to make the input current sinusoidal; the parallel converter is controlled as a sinusoidal voltage source to make the load voltage a standard sinusoidal value. Select the appropriate control strategy according to the structure of steps S1 and S3. If there are multiple power quality problems in the system and there are high requirements for compensation accuracy, select an indirect control strategy; if the control system design is simple and needs to maintain a stable compensation effect, select a direct control strategy.

8. A transformer power quality control method according to claim 1 or 2, characterized in that: In step S3, the calculated three-phase imbalance, power factor and harmonic distortion rate are compared with the target thresholds of power quality control set in step S1. If the thresholds are exceeded, it indicates that there is a power quality problem in the power system.

9. A system using a transformer power quality control method as claimed in any one of claims 1 to 7, characterized in that: It includes adjustment module, monitoring module, control module, communication module, feedback module and data storage module; The adjustment module includes a transformer and a unified power quality controller, which performs power quality compensation and adjustment on the power system by adjusting voltage, current and phase to improve power quality; The monitoring module includes a voltmeter, an ammeter, and a power quality analyzer to monitor and analyze power quality issues in the power system; the control module is used to control the output of the electronic power transformer in real time; The communication module is used to transmit data in the power system to an external system and receive instructions from the external system; The feedback module is used to evaluate the effect of the control strategy after implementation and to make feedback adjustments; The data storage module is used to store various data in the power system and generate reports.

10. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of a transformer power quality control method according to any one of claims 1 to 7 are implemented.

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