A Control Method and System for a Power Grid Dynamic Reactive Power Compensator

Abstract

The present invention discloses a control method and system for a power grid dynamic reactive power compensator, which relates to the technical field of compensator control. After analyzing the error value by using the PID control algorithm, a control signal for the compensator is generated, and the reactive power amplitude output by the AC of the compensator is adjusted according to the control signal. The control system simultaneously analyzes the health state of the compensator, and judges whether it is necessary to perform secondary adjustment on the reactive power amplitude output by the AC according to the analysis result of the health state. Based on the adjustment result, the compensator is controlled to provide or absorb the reactive power amplitude, and the power factor of the power grid is adjusted in real time. The control system quickly controls the compensator based on the PID control algorithm combined with the current situation of the power grid, effectively reducing the fluctuation of the power supply system and improving the power quality. Moreover, by combining the health state of the compensator itself to perform secondary optimization judgment on the reactive power amplitude, the stability of the power grid operation is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of compensator control, and particularly relates to a control method and system for a power grid dynamic reactive power compensator. Background Art

[0002] The construction of a new digital intelligent power grid is the main trend of current power grid development. Reactive power compensation and harmonic problems face new challenges in the intelligent power grid environment. As a new technology, a dynamic reactive power compensation device (SVG) can better solve the problem that the power factor of the power supply system will decrease due to insufficient amplitude of reactive power in the power system, thereby reducing equipment heating loss and line loss and prolonging the service life of electrical equipment.

[0003] The existing technologies have the following deficiencies:

[0004] 1. When designed, the compensator is optimized for specific load conditions, making it difficult to adapt to the rapidly changing power grid environment. Moreover, the compensator only adjusts the amplitude of reactive power compensation based on the power factor of the power grid, without combining the health status of the compensator itself for subsequent possible optimizations, and cannot ensure the stable operation of the compensator, resulting in poor adaptability of the dynamic regulation of the amplitude of reactive power in special scenarios.

[0005] 2. Due to the lack of real-time data processing and fast control strategies, when facing dynamic load changes, the reactive power compensator often causes a decrease in the power factor of the power grid due to response delay, easily leading to power supply fluctuations in the power grid and affecting the stability of power grid operation. Summary of the Invention

[0006] The purpose of the present invention is to provide a control method and system for a power grid dynamic reactive power compensator, which quickly controls the compensator based on the PID control algorithm combined with the current situation of the power grid, effectively reduces the fluctuations of the power supply system, improves the power quality, and further optimizes and judges the amplitude of reactive power by combining the health status of the compensator itself, thereby further improving the stability of power grid operation.

[0007] To achieve the above purpose, the present invention provides the following technical solution: A control method for a power grid dynamic reactive power compensator, the control method comprising the following steps:

[0008] The control system collects power parameters in the power grid in real time, calculates the error value between the actual value and the target value in the power parameters, and after analyzing the error value using the PID control algorithm, generates a control signal for the compensator;

[0009] According to the control signal, the amplitude of the reactive power output by the AC of the compensator is adjusted. During the PID control analysis process, the control system simultaneously analyzes the health status of the compensator and judges whether it is necessary to perform secondary adjustment on the amplitude of the reactive power output by the AC according to the analysis result of the health status;

[0010] Based on the regulation result, the control compensator provides or absorbs the reactive power amplitude, adjusts the power factor of the power grid in real time, and generates corresponding control strategies according to the analysis result of the health status of the compensator.

[0011] In a preferred embodiment, after analyzing the error value using the PID control algorithm, a control signal for the compensator is generated, including the following steps:

[0012] After the PID controller obtains the error value, the error value is substituted into the PID control algorithm to calculate and obtain the output value ;

[0013] Compare the real-time power factor with the power factor monitoring range The comparison result set outputs the value to generate a control signal for the compensator. If , and , it indicates that the real-time power factor in the power grid is low, and a control signal is generated to require the compensator to provide the reactive power amplitude to the power grid;

[0014] If , and , it indicates that the real-time power factor in the power grid is high, and a control signal is generated to require the compensator to absorb the reactive power amplitude from the power grid;

[0015] If , no control signal is generated, is the output threshold, is the real-time power factor, represents the minimum power factor threshold, represents the maximum power factor threshold.

[0016] In a preferred embodiment, after the PID controller obtains the error value, the error value is substituted into the PID control algorithm to calculate and obtain the output value, and the expression is: , where is the output value, is the error value, represents the cumulative duration, , , are the proportional gain, integral gain, and differential gain respectively, and , , are all greater than 0, is the integral term, is the differential term.

[0017] In a preferred embodiment, adjusting the reactive power amplitude output by the AC of the compensator according to the control signal includes the following steps:

[0018] The control system obtains the maximum value of the reactive power amplitude absorbed by the compensator and the maximum value of the reactive power amplitude output by the compensator, and obtains the output value of the PID control;

[0019] When the control signal is that the compensator needs to provide reactive power amplitude to the power grid, the adjustment algorithm is:

[0020] , where is the reactive power amplitude provided, is the output value, is the maximum value of the reactive power amplitude output by the compensator;

[0021] When the control signal is that the compensator needs to absorb reactive power amplitude from the power grid, the adjustment algorithm is:

[0022] , where is the reactive power amplitude absorbed, is the output value, is the maximum value of the reactive power amplitude absorbed by the compensator.

[0023] In a preferred embodiment, during the PID control analysis process, the control system simultaneously analyzes the health status of the compensator, including the following steps:

[0024] The control system obtains the harmonic content of the compensator and the normalized value of the multi-component temperature increase, normalizes the harmonic content and the normalized value of the multi-component temperature increase, maps the value range of the harmonic content and the normalized value of the multi-component temperature increase to between [0, 1], obtains the normalized value of the harmonic content and the normalized value of the multi-component temperature increase, subtracts the normalized value of the multi-component temperature increase from the normalized value of the harmonic content to obtain the health factor of the compensator. The larger the value of the health factor of the compensator, the worse the health status of the compensator. Compare the obtained health factor with the preset abnormal threshold. If the health factor is greater than the abnormal threshold, analyze that the health status of the compensator is poor. If the health factor is less than or equal to the abnormal threshold, analyze that the health status of the compensator is good.

[0025] In a preferred embodiment, the harmonic components in the compensator current waveform are analyzed by Fourier transform, and the calculation expression of the harmonic content is: , where is the harmonic content, is the period of the signal, is the instantaneous value of the signal over time , is the harmonic order, is the imaginary unit, and , is the angular frequency term.

[0026] In a preferred embodiment, the calculation logic of the multi-component temperature growth assignment is as follows: Obtain the temperature growth rate of each component in the compensator, calculate the average temperature growth rate and the standard deviation of the temperature growth rate based on the temperature growth rates of multiple components, and generate a multi-component temperature growth assignment according to the average temperature growth rate and the standard deviation of the temperature growth rate;

[0027] If the average temperature growth rate is less than or equal to the growth rate threshold and the standard deviation of the temperature growth rate is less than or equal to the standard deviation threshold, the multi-component temperature growth assignment is equal to 5.2;

[0028] If the average temperature growth rate is less than or equal to the growth rate threshold and the standard deviation of the temperature growth rate is greater than the standard deviation threshold, the multi-component temperature growth assignment is equal to 4.8;

[0029] If the average temperature growth rate is greater than the growth rate threshold and the standard deviation of the temperature growth rate is greater than the standard deviation threshold, the multi-component temperature growth assignment is equal to 4.0;

[0030] If the average temperature growth rate is greater than the growth rate threshold and the standard deviation of the temperature growth rate is less than or equal to the standard deviation threshold, the multi-component temperature growth assignment is equal to 3.2.

[0031] In a preferred embodiment, it is judged whether secondary adjustment of the reactive power amplitude output by the AC is required according to the health status analysis result, and the compensator is controlled to provide or absorb the reactive power amplitude based on the adjustment result, and the power factor of the power grid is adjusted in real time, including the following steps:

[0032] When the health status of the compensator is analyzed to be good, it is judged that secondary adjustment of the reactive power amplitude output by the AC is not required. When the health status of the compensator is analyzed to be poor, it is judged that secondary adjustment of the reactive power amplitude output by the AC is required, that is, it is necessary to reduce the provided reactive power amplitude or the absorbed reactive power amplitude of the compensator. The secondary adjustment algorithm is:

[0033] , where is the provided reactive power amplitude after secondary adjustment, is the provided reactive power amplitude before secondary adjustment, is the absorbed reactive power amplitude after secondary adjustment, is the absorbed reactive power amplitude before secondary adjustment, is the health factor;

[0034] The power factor of the power grid is adjusted in real time according to the provided reactive power amplitude after secondary adjustment or the absorbed reactive power amplitude after secondary adjustment.

[0035] In a preferred embodiment, the control system collects power parameters in the power grid in real time and calculates the error value between the actual value and the target value in the power parameters, including the following steps:

[0036] The control system obtains the active power amplitude and the reactive power amplitude of the power grid, and calculates the power factor based on the active power amplitude and the reactive power amplitude. The expression is: , where is the power factor, is the active power amplitude, is the reactive power amplitude;

[0037] The control system obtains the real-time power factor of the power grid, compares the real-time power factor with the preset power factor monitoring range , and calculates the error value based on the comparison result between the real-time power factor and the preset power factor monitoring range. The expression is:

[0038] , where is the error value, is the real-time power factor, represents the minimum power factor threshold, represents the maximum power factor threshold.

[0039] A control system for a power grid dynamic reactive power compensator includes a calculation module, a primary regulation module, and a secondary regulation module;

[0040] Calculation module: Collects power parameters in the power grid in real time and calculates the error value between the actual value and the target value in the power parameters;

[0041] Primary regulation module: After analyzing the error value using the PID control algorithm, generates a control signal for the compensator to ensure accurate and rapid response of the reactive power amplitude compensation, and adjusts the reactive power amplitude output by the AC of the compensator according to the control signal;

[0042] Secondary regulation module: During the PID control analysis process, analyzes the health status of the compensator at the same time, and determines whether secondary regulation of the reactive power amplitude output by the AC is required based on the analysis result of the health status. Controls the compensator to provide or absorb reactive power amplitude based on the regulation result, adjusts the power factor of the power grid in real time, and generates corresponding control strategies based on the analysis result of the health status of the compensator.

[0043] In the above technical solution, the technical effects and advantages provided by the present invention are:

[0044] 1. After analyzing the error value using the PID control algorithm, the present invention generates a control signal for the compensator, adjusts the reactive power amplitude output by the AC of the compensator according to the control signal, the control system simultaneously analyzes the health status of the compensator, and determines whether secondary adjustment of the reactive power amplitude output by the AC is required based on the analysis result of the health status. Based on the adjustment result, the compensator is controlled to provide or absorb the reactive power amplitude, and the power factor of the power grid is adjusted in real time. The control system quickly controls the compensator based on the PID control algorithm combined with the current situation of the power grid, effectively reducing the fluctuation of the power supply system, improving the power quality, and further optimizing and judging the reactive power amplitude in combination with the health status of the compensator itself, further improving the stability of the power grid operation;

[0045] 2. During the PID control analysis process of the present invention, the control system simultaneously analyzes the health status of the compensator, determines whether secondary adjustment of the reactive power amplitude output by the AC is required based on the analysis result of the health status, controls the compensator to provide or absorb the reactive power amplitude based on the adjustment result, adjusts the power factor of the power grid in real time, and generates a corresponding control strategy based on the analysis result of the health status of the compensator, so as to effectively control and manage the compensator. Brief Description of the Drawings

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings.

[0047] Figure 1 It is the flowchart of the method of the present invention. Detailed Embodiments

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0049] Embodiment 1: Please refer to Figure 1 As shown, a control method for a power grid dynamic reactive power compensator in this embodiment includes the following steps:

[0050] The control system collects the power parameters in the power grid in real time through current and voltage sensors, such as voltage, reactive power amplitude, and power factor, calculates the error value between the actual value and the target value in the power parameters, and after analyzing the error value using the PID control algorithm, generates a control signal for the compensator to ensure accurate and rapid response of the reactive power amplitude compensation. According to the control signal, it adjusts the reactive power amplitude output by the AC of the compensator. During the PID control analysis process, the control system simultaneously analyzes the health status of the compensator, and based on the analysis result of the health status, determines whether secondary adjustment of the reactive power amplitude output by the AC is required. Based on the adjustment result, it controls the compensator to provide or absorb reactive power amplitude, adjusts the power factor of the power grid in real time, and generates corresponding control strategies based on the analysis result of the health status of the compensator.

[0051] In this application, after analyzing the error value using the PID control algorithm, a control signal for the compensator is generated. According to the control signal, the reactive power amplitude output by the AC of the compensator is adjusted. The control system simultaneously analyzes the health status of the compensator, and based on the analysis result of the health status, determines whether secondary adjustment of the reactive power amplitude output by the AC is required. Based on the adjustment result, it controls the compensator to provide or absorb reactive power amplitude, and adjusts the power factor of the power grid in real time. The control system quickly controls the compensator based on the PID control algorithm combined with the current situation of the power grid, effectively reducing the fluctuations of the power supply system, improving the power quality, and further optimizing and judging the reactive power amplitude in combination with the health status of the compensator itself, further improving the stability of the power grid operation;

[0052] During the PID control analysis process of this application, the control system simultaneously analyzes the health status of the compensator, and based on the analysis result of the health status, determines whether secondary adjustment of the reactive power amplitude output by the AC is required. Based on the adjustment result, it controls the compensator to provide or absorb reactive power amplitude, adjusts the power factor of the power grid in real time, and generates corresponding control strategies based on the analysis result of the health status of the compensator, so as to effectively control and manage the compensator.

[0053] Embodiment 2: The control system collects the power parameters in the power grid in real time through current and voltage sensors, such as voltage, reactive power amplitude, and power factor, and calculates the error value between the actual value and the target value in the power parameters, including the following steps:

[0054] The control system obtains the active power amplitude and reactive power amplitude of the power grid, and calculates the power factor based on the active power amplitude and reactive power amplitude. The expression is: , where is the power factor, is the active power amplitude, is the reactive power amplitude;

[0055] The control system obtains the real-time power factor of the power grid and compares the real-time power factor with the preset power factor monitoring range and calculates the error value based on the comparison result between the real-time power factor and the preset power factor monitoring range. The expression is:

[0056] , where is the error value, is the real-time power factor, represents the minimum power factor threshold, represents the maximum power factor threshold.

[0057] That is, in this application, the actual value in the electrical parameters is the power factor, and the target value is the power factor monitoring range .

[0058] It should be noted that when the error value is equal to 0, it means that the power factor of the power grid is in a stable state, and there is no need to control the operation of the compensator.

[0059] After analyzing the error value using the PID control algorithm, a control signal for the compensator is generated to ensure accurate and rapid reactive power amplitude compensation, including the following steps:

[0060] After the PID controller obtains the error value, it substitutes the error value into the PID control algorithm to calculate and obtain the output value. The expression is: , where is the output value, is the error value, represents the cumulative duration, , , are the proportional gain, integral gain, and derivative gain respectively, and , , are all greater than 0, is the integral term, is the derivative term;

[0061] A control signal for the compensator is generated through the output value, enabling the compensator to respond quickly, adjust the provision or absorption of reactive power amplitude, and maintain the stability of the power factor of the power grid. Moreover, during the PID control process, the system will continuously analyze the trend of the error value and the control output, and perform , , dynamic adjustment to optimize the control strategy and make the compensation response faster and more accurate.

[0062] During the compensation process, an anti-integral saturation strategy is added to avoid slow system response caused by excessive integral terms. The commonly used anti-saturation function is: , where is the maximum limit value of the integral term.

[0063] Compare the real-time power factor with the power factor monitoring range The comparison result set outputs a value to generate a control signal for the compensator. If , and , is the output threshold, indicating that the real-time power factor in the power grid is low, and a control signal is generated that requires the compensator to provide the reactive power amplitude to the power grid. If , and , it indicates that the real-time power factor in the power grid is high, and a control signal is generated that requires the compensator to absorb the reactive power amplitude from the power grid. If , no control signal is generated.

[0064] In summary: at low power factors, the compensator provides reactive power amplitude to improve efficiency; at normal power factors, the compensator maintains a balanced state; at high power factors, the compensator absorbs reactive power amplitude to avoid overvoltage. Such dynamic adjustment can ensure the stability and security of the power grid and optimize the power utilization efficiency.

[0065] Proportional gain: This is the gain coefficient of the proportional control part. The proportional gain controls the response intensity of the current error value and determines the influence of the error on the control signal. A higher value will increase the output of the controller, enhance the system's response to the error, but may cause the system to be unstable.

[0066] Integral gain: This is the gain coefficient of the integral control part. The integral gain determines the cumulative effect of the error over time. It eliminates the steady-state error by accumulating the historical values of the error, enabling the system to reach the target value more precisely. A higher value can eliminate the steady-state error, but may also cause the system to overshoot or oscillate.

[0067] Derivative gain: This is the gain coefficient of the derivative control part. The derivative gain controls the response speed of the error change, predicts future errors based on the change trend of the error, and plays a role in suppressing system overshoot and oscillation. A higher value can improve the stability of the system, but may also increase the noise sensitivity.

[0068] For example:

[0069] 1) Low power factor condition: The real-time power factor of a certain power grid is 0.7 (lower than the minimum power factor threshold of 0.9). The power grid mainly consists of inductive loads (such as motors). At this time, the demand for the reactive power amplitude in the system is relatively high, resulting in a low utilization efficiency of the active power amplitude. The existence of the reactive power amplitude increases the apparent power. The compensator (such as a dynamic reactive power compensator, SVG) needs to provide additional reactive power amplitude to increase the power factor to the minimum power factor threshold (0.9). This can reduce the demand for reactive power amplitude in the power grid and improve the power utilization efficiency.

[0070] 2) Normal power factor condition: The real-time power factor of the power grid is 0.9, within the power factor monitoring range, the load condition is normal, and the reactive power amplitude and the active power amplitude in the power grid are relatively balanced. At this time, the power grid operates well and no compensation is required. The reactive power amplitude is moderate, and the power factor meets the system requirements. In this case, the compensator remains in a standby state, ready to respond to power grid changes at any time.

[0071] 3) High power factor condition: The power factor of the power grid is 1.1 (higher than the maximum power factor threshold of 1.0). There are too many capacitive loads (such as power capacitor banks) in the power grid. At this time, the reactive power amplitude in the power grid may be negative, which means there is excess reactive power amplitude in the power grid. This may cause the system voltage to rise and affect the normal operation of equipment. The compensator needs to absorb the reactive power amplitude to reduce the influence of capacitive loads and prevent the voltage from being too high. By adjusting the reactive power amplitude output, the compensator can reduce the power factor to a reasonable range (0.95 - 1.0).

[0072] Adjusting the reactive power amplitude output of the compensator's AC according to the control signal includes the following steps:

[0073] The control system obtains the maximum reactive power amplitude absorption value and the maximum reactive power amplitude output value of the compensator, and obtains the output value of the PID control;

[0074] When the control signal requires the compensator to provide reactive power amplitude to the power grid, the adjustment algorithm is:

[0075] , where is the provided reactive power amplitude, is the output value, is the maximum reactive power amplitude output value of the compensator;

[0076] When the control signal requires the compensator to absorb reactive power amplitude from the power grid, the adjustment algorithm is:

[0077] , where is the absorbed reactive power amplitude, is the output value, is the maximum reactive power amplitude absorption of the compensator.

[0078] To better illustrate the above solution, the following is an example of this application:

[0079] Assume that the minimum power factor threshold of the power grid is 0.95, and the currently measured power factor is 0.85. According to the actual situation of the power grid, the compensator needs to adjust the reactive power amplitude output to improve the power factor;

[0080] The calculated error value ;

[0081] Let the proportional gain, integral gain, and derivative gain be , , respectively, then the calculated PID control output value ;

[0082] The control signal represents the amplitude of the reactive power amplitude output that the compensator needs to provide. According to the specific control logic (such as a linear proportional relationship), the PID output is converted into the specific reactive power amplitude provided. Let the maximum reactive power amplitude output of the compensator be 100 VAR, and the expression is: VAR;

[0083] That is, the compensator will provide a reactive power amplitude output of 24.5 VAR to help improve the power factor of the power grid, thereby adjusting the power factor to be close to the minimum power factor threshold of 0.95;

[0084] From this example, it can be seen that the PID controller dynamically adjusts the output signal according to the real-time error, thereby generating the reactive power amplitude output required by the compensator to ensure that the power factor is stable near the target value. This control method enables the system to quickly respond to changes and maintain the stability and efficiency of the power grid.

[0085] The calculation method of the absorbed reactive power amplitude is the same as above and will not be elaborated here.

[0086] During the PID control analysis process, the control system simultaneously analyzes the health status of the compensator, including the following steps:

[0087] The control system obtains the harmonic content of the compensator and the assignment of the temperature increase of multiple components, normalizes the harmonic content and the assignment of the temperature increase of multiple components, maps the value range of the harmonic content and the assignment of the temperature increase of multiple components to between [0, 1], obtains the normalized value of the harmonic content and the normalized value of the assignment of the temperature increase of multiple components, subtracts the normalized value of the assignment of the temperature increase of multiple components from the normalized value of the harmonic content to obtain the health factor of the compensator. The larger the value of the health factor of the compensator, the worse the health state of the compensator. Compare the obtained health factor with the preset abnormal threshold. If the health factor is greater than the abnormal threshold, analyze that the health state of the compensator is poor. If the health factor is less than or equal to the abnormal threshold, analyze that the health state of the compensator is good;

[0088] Analyze the harmonic components in the compensator current waveform through Fourier transform. The calculation expression of the harmonic content is: , where is the harmonic content, is the period of the signal, which is the time length for the signal to repeat in time, usually the power frequency period of the power grid (for example, 50 Hz corresponds to T = 1 / 50 second), is the instantaneous value of the signal with respect to time , and this signal is usually the time-domain representation of voltage or current, is the harmonic order (taking an integer), representing the ordinal number of the harmonic in the Fourier decomposition. The harmonic order of the main frequency n = 1, the second harmonic n = 2, and so on, is the imaginary unit, and , in the Fourier transform, the imaginary unit is used to calculate the complex-valued harmonic components, including amplitude and phase information, is the angular frequency term, representing the angular frequency of the nth harmonic. It defines the rotational speed of each harmonic frequency component within the period T. The larger the harmonic content, the worse the health state of the compensator. Specifically:

[0089] Equipment overload: High harmonic content can cause the internal components of the compensator (such as capacitors and inductors) to be overloaded, increase heat generation, and reduce their lifespan.

[0090] Energy loss: The non-linear load caused by harmonics will lead to energy loss, increase the heat generation and loss of the equipment, thereby affecting performance.

[0091] Power quality degradation: High harmonic content will reduce the power quality, cause voltage waveform distortion, and may cause other equipment failures or performance degradation.

[0092] Protection device triggering: Excessive harmonics may cause the protection device to trigger erroneously, affecting the normal operation of the system.

[0093] System instability: Harmonic interference may cause the control system to be unstable, affecting the response ability of the compensator.

[0094] Accelerated aging: The influence of harmonics will accelerate the aging of the compensator components, reducing their reliability and stability.

[0095] The calculation logic of the multi-component temperature growth assignment is as follows: Obtain the temperature growth rate of each component in the compensator, calculate the average value and standard deviation of the temperature growth rate based on the temperature growth rates of multiple components. The expression is:

[0096] , where is the standard deviation of the temperature growth rate, is the average value of the temperature growth rate, is the number of components in the compensator, is the th component's temperature growth rate;

[0097] Generate the multi-component temperature growth assignment based on the average value of the temperature growth rate and the standard deviation of the temperature growth rate;

[0098] If the average value of the temperature growth rate is less than or equal to the growth rate threshold, and the standard deviation of the temperature growth rate is less than or equal to the standard deviation threshold, it is analyzed that the overall temperature growth rate inside the compensator is slow, and the multi-component temperature growth assignment is equal to 5.2;

[0099] If the average value of the temperature growth rate is less than or equal to the growth rate threshold, and the standard deviation of the temperature growth rate is greater than the standard deviation threshold, it is analyzed that the temperature growth rate inside the compensator is slow, but there are some components whose temperature growth rate is greater than the growth rate threshold, and the multi-component temperature growth assignment is equal to 4.8;

[0100] If the average value of the temperature growth rate is greater than the growth rate threshold, and the standard deviation of the temperature growth rate is greater than the standard deviation threshold, it is analyzed that the temperature growth rate inside the compensator is fast, but there are some components whose temperature growth rate is less than or equal to the growth rate threshold, and the multi-component temperature growth assignment is equal to 4.0;

[0101] If the average value of the temperature growth rate is greater than the growth rate threshold, and the standard deviation of the temperature growth rate is less than or equal to the standard deviation threshold, it is analyzed that the overall temperature growth rate inside the compensator is fast, and the multi-component temperature growth assignment is equal to 3.2;

[0102] In summary, the smaller the value of the multi-component temperature growth assignment, the faster the overall temperature growth rate inside the compensator, that is, the worse the health state of the compensator.

[0103] And judge whether it is necessary to perform secondary regulation on the reactive power amplitude output by the AC according to the health state analysis result, and control the compensator to provide or absorb the reactive power amplitude based on the regulation result, and adjust the power factor of the power grid in real time, including the following steps:

[0104] When the health state of the compensator is good, it is determined that there is no need to perform secondary adjustment on the amplitude of the reactive power output by the AC device. When the health state of the compensator is poor, it is determined that secondary adjustment is required for the amplitude of the reactive power output by the AC device, that is, it is necessary to reduce the amplitude of the reactive power provided or absorbed by the compensator. The secondary adjustment algorithm is as follows:

[0105] , where is the amplitude of the reactive power provided after secondary adjustment, is the amplitude of the reactive power provided before secondary adjustment, is the amplitude of the reactive power absorbed after secondary adjustment, is the amplitude of the reactive power absorbed before secondary adjustment, is the health factor;

[0106] The power factor of the power grid is adjusted in real time according to the amplitude of the reactive power provided after secondary adjustment or the amplitude of the reactive power absorbed after secondary adjustment.

[0107] A corresponding control strategy is generated according to the analysis result of the health state of the compensator, including the following steps:

[0108] If the health factor is greater than the abnormal threshold, it is analyzed that the health state of the compensator is poor. The larger the health factor, the worse the health state of the compensator. Therefore, the health factor greater than the abnormal threshold is compared with the warning threshold. The warning threshold is greater than the abnormal threshold. When the health factor is greater than the abnormal threshold and less than or equal to the warning threshold, it indicates that the compensator has a minor abnormality and can still be used. If the health factor is greater than the warning threshold, it indicates that the compensator has a serious abnormality and cannot be used. At this time, the control system controls the compensator to stop running and sends a warning signal to the administrator.

[0109] Embodiment 3: The control system of a power grid dynamic reactive power compensator described in this embodiment includes a calculation module, a primary adjustment module, and a secondary adjustment module;

[0110] Calculation module: Real-time collect power parameters in the power grid, such as voltage, reactive power amplitude, and power factor, through current and voltage sensors, calculate the error value between the actual value and the target value in the power parameters, and send the error value to the primary adjustment module;

[0111] Primary adjustment module: After analyzing the error value using the PID control algorithm, generate a control signal for the compensator to ensure accurate and rapid response of reactive power amplitude compensation, adjust the amplitude of the reactive power output by the AC device of the compensator according to the control signal, and send the adjusted reactive power amplitude to the secondary adjustment module;

[0112] Secondary regulation module: During the PID control analysis process, the health status of the compensator is analyzed simultaneously, and it is determined whether secondary regulation of the reactive power amplitude output by the AC is required based on the analysis result of the health status. The compensator is controlled to provide or absorb the reactive power amplitude based on the regulation result, the power factor of the power grid is adjusted in real time, and a corresponding control strategy is generated based on the analysis result of the health status of the compensator.

[0113] The above formulas are all dimensionless and take their numerical values for calculation. The formula is obtained by collecting a large amount of data for software simulation to get a formula closest to the actual situation. The preset parameters in the formula are set by those skilled in the art according to the actual situation.

[0114] It should be understood that the term "and / or" in this article is only a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. These three situations, where A and B can be singular or plural. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after, but it may also represent an "and / or" relationship, which can be specifically understood by referring to the context before and after.

[0115] It should be understood that in various embodiments of the present application, the magnitudes of the sequence numbers of the above processes do not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0116] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in this article can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present application. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working processes of the systems, devices, and units described above can refer to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0117] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present application, and all should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A control method for a dynamic reactive power compensator of a power grid, characterized in that: The control method comprises the following steps: The control system collects power parameters in the power grid in real time, calculates the error between the actual value and the target value of the power parameters, analyzes the error value using the PID control algorithm, and generates a control signal for the compensator; The reactive power amplitude of the AC output of the compensator is adjusted according to the control signal. During the PID control analysis, the control system simultaneously analyzes the health status of the compensator, and obtains the health factor of the compensator by subtracting the normalized value of the temperature growth of multiple components from the normalized value of the harmonic content. The health status of the AC is analyzed based on the comparison result between the health factor and the abnormal threshold. And according to the health status analysis results, it is determined whether it is necessary to perform secondary adjustment on the reactive power amplitude output by the AC device; Based on the adjustment result, the compensator is controlled to provide or absorb reactive power amplitude, and the power factor of the power grid is adjusted in real time. The control system obtains the maximum reactive power amplitude absorption and the maximum reactive power amplitude output of the compensator, and obtains the output value of the PID control. When the health status of the compensator is analyzed to be good, it is determined that there is no need to perform secondary adjustment on the reactive power amplitude output by the AC converter. When the health status of the compensator is analyzed to be poor, it is determined that there is a need for secondary adjustment on the reactive power amplitude output by the AC converter, that is, the reactive power amplitude provided or absorbed by the compensator needs to be reduced.

2. A method for controlling a dynamic reactive power compensator of a power grid according to claim 1, characterized in that: After analyzing the error value using the PID control algorithm, a control signal for the compensator is generated, including the following steps: After the PID controller obtains the error value, it substitutes the error value into the PID control algorithm to calculate the output value ; Combine the real-time power factor with the power factor monitoring range The comparison result sets the output value to generate the control signal for the compensator. ,and , indicating that the real-time power factor in the grid is low, generating a control signal requiring the compensator to provide reactive power amplitude to the grid; like ,and , indicating that the real-time power factor in the grid is high, generating a control signal that requires the compensator to absorb reactive power amplitude into the grid; like , no control signal is generated, is the output threshold, is the real-time power factor, represents the minimum power factor threshold, Indicates the maximum power factor threshold.

3. A method for controlling a dynamic reactive power compensator of a power grid according to claim 2, characterized in that: After the PID controller obtains the error value, the error value is substituted into the PID control algorithm to calculate and obtain the output value, and the expression is: , where is the output value, is the error value, Indicates the cumulative duration. , , are proportional gain, integral gain and differential gain respectively, and , , are greater than 0, is the integral term, is the differential term.

4. A method for controlling a dynamic reactive power compensator of a power grid according to claim 3, characterized in that: The reactive power amplitude of the AC output of the compensator is adjusted according to the control signal, including the following steps: The control system obtains the maximum reactive power amplitude absorption value and the maximum reactive power amplitude output value of the compensator, and obtains the output value of the PID control; When the control signal requires the compensator to provide reactive power amplitude to the grid, the regulation algorithm is: , where To provide the reactive power amplitude, is the output value, The maximum value of the reactive power amplitude output of the compensator; When the control signal requires the compensator to absorb reactive power amplitude from the grid, the regulation algorithm is: , where To absorb the reactive power amplitude, is the output value, It is the maximum value of reactive power amplitude absorbed by the compensator.

5. A method for controlling a dynamic reactive power compensator of a power grid according to claim 4, characterized in that: The calculation expression of the harmonic content is: , where is the harmonic content, is the period of the signal, The signal over time The instantaneous value of is the harmonic order, is an imaginary unit, and , is the angular frequency term.

6. A method for controlling a dynamic reactive power compensator of a power grid according to claim 5, characterized in that: The calculation logic of the multi-component temperature growth assignment is: obtaining the temperature growth rate of each component in the compensator, calculating the temperature growth rate mean and the temperature growth rate standard deviation based on the temperature growth rates of the multiple components, and generating the multi-component temperature growth assignment according to the temperature growth rate mean and the temperature growth rate standard deviation; If the mean temperature growth rate is less than or equal to the growth rate threshold, and the standard deviation of the temperature growth rate is less than or equal to the standard deviation threshold, the multi-component temperature growth value is equal to 5.2; If the mean of the temperature growth rate is less than or equal to the growth rate threshold, and the standard deviation of the temperature growth rate is greater than the standard deviation threshold, the temperature growth of multiple components is assigned a value of 4.8; If the mean temperature growth rate is greater than the growth rate threshold, and the standard deviation of the temperature growth rate is greater than the standard deviation threshold, the multi-component temperature growth value is equal to 4.0; If the mean temperature growth rate is greater than the growth rate threshold, and the standard deviation of the temperature growth rate is less than or equal to the standard deviation threshold, the multi-component temperature growth value is assigned to be equal to 3.

2.

7. A method for controlling a dynamic reactive power compensator of a power grid according to claim 6, characterized in that: According to the health status analysis result, it is determined whether the reactive power amplitude output by the AC device needs to be adjusted for a second time, and based on the adjustment result, the compensator is controlled to provide or absorb reactive power amplitude, and the power factor of the power grid is adjusted in real time, including the following steps: When the health status of the compensator is good, it is determined that there is no need to perform secondary adjustment on the reactive power amplitude of the AC output. When the health status of the compensator is poor, it is determined that secondary adjustment is required for the reactive power amplitude of the AC output, that is, the reactive power amplitude provided by the compensator or the reactive power amplitude absorbed by the compensator needs to be reduced. The secondary adjustment algorithm is: , where Provide reactive power amplitude after secondary regulation, To provide reactive power amplitude before secondary regulation, is the absorbed reactive power amplitude after secondary regulation, is the absorbed reactive power amplitude before secondary regulation, It is a health factor; The power factor of the power grid is adjusted in real time according to the reactive power amplitude provided after secondary regulation or the reactive power amplitude absorbed after secondary regulation.

8. A method for controlling a dynamic reactive power compensator of a power grid according to claim 7, characterized in that: The control system collects power parameters in the power grid in real time and calculates the error value between the actual value and the target value of the power parameters, including the following steps: The control system obtains the active power amplitude and reactive power amplitude of the power grid, and calculates the power factor based on the active power amplitude and reactive power amplitude. The expression is: , where is the power factor, is the active power amplitude, is the reactive power amplitude; The control system obtains the real-time power factor of the power grid and compares the real-time power factor with the preset power factor monitoring range. Compare and calculate the error value based on the comparison result between the real-time power factor and the preset power factor monitoring range. The expression is: , where is the error value, is the real-time power factor, represents the minimum power factor threshold, Indicates the maximum power factor threshold.

9. A power grid dynamic reactive power compensator control system, used to implement the control method according to any one of claims 1 to 8, characterized in that: It includes a calculation module, a primary adjustment module and a secondary adjustment module; Calculation module: collects power parameters in the power grid in real time and calculates the error between the actual value and the target value of the power parameters; Primary regulation module: After analyzing the error value using the PID control algorithm, a control signal for the compensator is generated, and the reactive power amplitude output by the compensator's AC device is adjusted according to the control signal; Secondary regulation module: During the PID control analysis process, the health status of the compensator is analyzed at the same time, and based on the health status analysis results, it is determined whether the reactive power amplitude output by the AC converter needs to be secondary adjusted. Based on the adjustment results, the compensator is controlled to provide or absorb reactive power amplitude, and the power factor of the power grid is adjusted in real time.

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