Reactive compensation control method for power distribution network

Abstract

The invention relates to the technical field of power distribution network reactive compensation, and discloses a power distribution network reactive compensation control method. The reactive compensation control method for the power distribution network comprises the following steps: information sampling; sampling and analyzing; analyzing temperature rise; performing operation analysis; monitoring power loss; the method ensures that a large power plant can provide enough active hot standby for a load center, meets the requirement of reactive voltage support, enables sufficient reactive standby capacity to be formed at each load node and hub node during the operation of a power system, avoids the malignant event of voltage collapse caused by the lack of reactive power of the system, and improves the reliability of the system. The method can guarantee safe and stable operation of a power grid, can timely quit capacitor operation after equipment operation encounters a power-off condition, can ensure data integrity in a certain time interval, can effectively avoid adverse effects on equipment under the power-off condition, and can adjust a sampling interval in real time during actual operation of a power distribution network system. And the accuracy of information sampling analysis is ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of reactive power compensation for power distribution networks, and in particular relates to a reactive power compensation control method for power distribution networks. Background Art

[0002] In recent years, the scale of power distribution network construction in my country has been expanding, and the safe and stable operation of power distribution networks has become a focus of attention. Among them, the problem of reactive power compensation is the focus of power distribution network operation control technology. In actual operation, the inadequate configuration of system reactive power compensation devices and the lack of reactive power reserve capacity are problems that cannot be ignored. In particular, without sufficient rapid adjustment of reactive power compensation capacity and supporting devices, the real-time response capability of the system is insufficient. At present, under the background of the widespread use and continuous growth of high-power power electronic components, the requirements for system reactive power regulation continue to increase, especially reasonable and effective control methods are very important, which can ensure that the bus voltage remains stable when the system power flow fluctuates, especially for the operation of the distribution network, which will directly affect the voltage and line loss qualification rate indicators; therefore, in view of the current situation, it is necessary to improve it. Summary of the invention

[0003] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides a reactive compensation control method for a distribution network, which effectively solves the problems that cannot be ignored in actual operation, such as inadequate configuration of reactive compensation devices in the system and lack of reactive reserve capacity, especially the lack of sufficient rapid adjustment of reactive compensation capacity and supporting devices, resulting in insufficient real-time response capability of the system.

[0004] To achieve the above object, the present invention provides the following technical solution: a method for reactive power compensation control in a power distribution network, characterized in that it comprises the following steps:

[0005] Step 1: Information sampling, using PDB to control the frequency of analog-to-digital signal acquisition, setting the basic value of the parameter in the register, triggering the interrupt execution operation within the specified period, and sending it to the analog-to-digital conversion unit for sampling. After the sampling is successful, it triggers the direct memory access information acquisition and transmission, adopts its data access mode to transmit the corresponding acquisition information to the digital-to-analog conversion unit, and stores it in its memory data buffer address;

[0006] Step 2: Sampling and analysis. Fourier calculation is performed for each frequency in the sampling address area. When the distribution network system is actually running, the operating frequency of the distribution network system fluctuates around the rated frequency, showing a real-time change trend. In order to achieve accurate information sampling and analysis, the sampling interval needs to be adjusted in time while the system operating frequency is constantly changing. After the collected information transmitted by the direct memory access unit meets the Fourier calculation requirements, the solution unit sends an instruction and the direct memory access unit stops transmitting. At this time, the frequency calculation value is used as the basis, and the parameters in the interrupt delay register are set again to ensure that the sampling of the analog-to-digital conversion unit meets the actual frequency requirements of the system. Then the direct memory access unit is started again to collect analog-to-digital information according to the updated sampling period.

[0007] Step 3: Temperature rise analysis. Temperature rise analysis is one of the basic functions of the equipment's own protection control. The sensor measurement unit monitors the temperature rise and performs judgment according to the set threshold. When the temperature rise is higher than the threshold, the compensator is executed to lock out and all the compensators in operation are exited at the same time.

[0008] Step 4: Operation analysis, select a reasonable adjustment strategy through information sampling, solve the appropriate compensator set, and in the power factor control process, give its objective function term, according to the voltage and current obtained by real-time sampling and the compensator control signal, give a reasonable compensation strategy after solving, and change the corresponding compensator state at the same time, so that the difference between the actual compensation amount and the required compensation amount is as small as possible. In the process of entering and exiting the compensator, use the optimal control method to find the most reasonable compensation strategy to achieve the effect of one-time compensation.

[0009] Step 5: Power failure monitoring. When the equipment encounters a power failure, timely exit the capacitor to ensure data integrity within a certain time period.

[0010] Preferably, the analog-to-digital conversion unit proposed in step one is used to convert the continuous change of the analog signal into a discrete digital value. The sampling is completed by discretizing the analog signal in time and then measuring the value of the signal within a specific time interval. The analog value obtained by sampling is divided into several levels, each level corresponds to a fixed digital value, and the quantized value is converted into a binary code for processing by the digital system.

[0011] Preferably, the Fourier calculation proposed in step 2 includes the frequency value, the voltage vector value of each phase and the voltage harmonic value of each phase up to the thirty-first order, wherein the voltage harmonic value is generated when the harmonic current flows through the line impedance, and the harmonic voltage is equal to the harmonic current multiplied by the grid impedance, and the grid impedance includes the impedance of the transformer and the impedance of the distribution line. Harmonic refers to the component greater than the fundamental frequency except the fundamental frequency component after the periodic non-sinusoidal electrical quantity is decomposed by the Fourier series.

[0012] Preferably, the compensator proposed in step three and step four includes a host and a slave, the host is used to ensure that the slave has no competitive relationship with it during normal operation, send parameter reading instructions to the slave in sequence, check and receive various parameter information sent back, including capacitance value, compensation type, switching signal, control type, temperature rise and threshold excess delay mark, sample voltage and current, and simultaneously calculate the real-time power flow of the system, including voltage, current and power value files, and calculate the power factor, voltage and current harmonic index values, sample the temperature sensor, and obtain the real-time temperature value.

[0013] Preferably, the slave is used to check the status of the broadcast host. When no information is received within the set time interval, the slave starts the competitive operation instruction, replaces the host after a given delay according to the local address information, checks the parameters sent by the host, reads the instructions, returns various parameter information, samples the voltage, and simultaneously calculates the real-time voltage value of the system, samples the thermometer, and obtains the real-time temperature value.

[0014] Preferably, the Fourier calculation proposed in step 2 includes Fourier series and Fourier transform, wherein the Fourier series is a type of trigonometric series used to represent periodic functions, and represents a periodic function as a linear combination of a series of sine and cosine functions, and the Fourier transform converts a non-periodic continuous signal in the time domain into a non-periodic continuous signal in the frequency domain.

[0015] Preferably, the registers proposed in step 1 and step 2 are small storage areas for storing data, and are used to temporarily store data involved in the operation and the results of the operation. The storage circuit of the register is composed of an iron register or a trigger, and can be used to temporarily store instructions, data and addresses.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. The present invention can ensure that large power plants can provide sufficient active hot standby for load centers and meet the needs of reactive voltage support, so that sufficient reactive standby capacity can be formed at each load node and hub node during the operation of the power system, effectively avoiding the occurrence of malicious incidents of voltage collapse caused by lack of reactive power in the system, and ensuring the safe and stable operation of the power grid.

[0017] 2. The present invention, through power failure monitoring, can promptly take capacitor exit operations after the device encounters a power failure during operation, thereby ensuring data integrity within a certain time interval and effectively avoiding adverse effects on the device caused by a power failure.

[0018] 3. In the present invention, when the power distribution network system is actually operating, the operating frequency of the power network system fluctuates above and below the rated frequency, presenting a real-time changing trend. While the system operating frequency is constantly changing, the sampling interval is adjusted in real time, and analog-to-digital information collection is carried out according to the updated sampling period, so as to ensure the accuracy of information sampling and analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0020] In the attached picture:

[0021] Figure 1 A block diagram of a reactive power compensation control method for a power distribution network according to the present invention;

[0022] Figure 2 This is a flowchart of step five in the reactive power compensation control method for a power distribution network of the present invention. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0024] See also Figure 1-Figure 2 The present invention provides a reactive power compensation control method for a power distribution network, comprising the following steps:

[0025] Step 1: Information sampling, using PDB to control the frequency of analog-to-digital signal acquisition, setting the basic parameter value in the register, triggering an interrupt execution operation within a specified period of time, and sending it to the analog-to-digital conversion unit for sampling. After successful sampling, it triggers direct memory access information acquisition and transmission, and adopts its data access mode to transmit the corresponding acquisition information to the digital-to-analog conversion unit and store it in its memory data buffer address.

[0026] Step 2: Sampling and analysis. Fourier calculation is performed for each frequency in the sampling address area. When the distribution network system is actually running, the operating frequency of the distribution network system fluctuates around the rated frequency, showing a real-time change trend. In order to achieve accurate information sampling and analysis, the sampling interval needs to be adjusted in time while the system operating frequency is constantly changing. After the collected information transmitted by the direct memory access unit meets the Fourier calculation requirements, the solution unit sends an instruction and the direct memory access unit stops transmitting. At this time, the frequency calculation value is used as the basis, and the parameters in the interrupt delay register are set again to ensure that the sampling of the analog-to-digital conversion unit meets the actual frequency requirements of the system. Then the direct memory access unit is started again to collect analog-to-digital information according to the updated sampling period.

[0027] Step 3: Temperature rise analysis. Temperature rise analysis is one of the basic functions of the equipment's own protection control. The sensor measurement unit monitors the temperature rise and performs judgment according to the set threshold. When the temperature rise is higher than the threshold, the compensator is executed to lock out and all the compensators in operation are exited at the same time.

[0028] Step 4: Operation analysis, select a reasonable adjustment strategy through information sampling, solve the appropriate compensator set, and in the power factor control process, give its objective function term, according to the voltage and current obtained by real-time sampling and the compensator control signal, give a reasonable compensation strategy after solving, and change the corresponding compensator state at the same time, so that the difference between the actual compensation amount and the required compensation amount is as small as possible. In the process of entering and exiting the compensator, use the optimal control method to find the most reasonable compensation strategy to achieve the effect of one-time compensation.

[0029] Step 5: Power failure monitoring. When the equipment encounters a power failure, timely exit the capacitor to ensure data integrity within a certain time period.

[0030] Among them, the analog-to-digital conversion unit proposed in step 1 is used to convert the continuous change of the analog signal into discrete digital values. The sampling is completed by discretizing the analog signal in time and then measuring the value of the signal within a specific time interval. The sampled analog value is divided into several levels, each level corresponds to a fixed digital value, and the quantized value is converted into a binary code for digital system processing. The Fourier calculation proposed in step 2 includes the frequency value, the voltage vector value of each phase, and the voltage harmonic value of each phase up to the thirty-first order. The voltage harmonic value is the harmonic current flow. The harmonic voltage is generated when the line impedance is crossed. The harmonic voltage is equal to the harmonic current multiplied by the grid impedance. The grid impedance includes the impedance of the transformer and the impedance of the distribution line. Harmonics refer to the components greater than the fundamental frequency except the fundamental frequency component after the periodic non-sinusoidal electric quantity is decomposed by the Fourier series. The compensator proposed in steps 3 and 4 includes a master and a slave. The master is used to ensure that the slave has no competitive relationship with it during normal operation. It sends parameter reading instructions to the slave in turn, and checks and receives various parameter information sent back, including capacitance value, compensation type, switching signal, control type, temperature rise and threshold excess delay mark , sample the voltage and current, and calculate the real-time power flow of the system, including the voltage, current and power value files, and calculate the power factor, voltage and current harmonic index values. Sample the thermometer to obtain the real-time temperature value. The slave is used to check the status of the host broadcast. When no information is received within the set time interval, the competition operation instruction is started. According to the local address information, after a given delay, it replaces the host, checks the parameters sent by the host, reads the instruction, and returns various parameter information. Sample the voltage and calculate the real-time voltage value of the system. Sample the thermometer to obtain the real-time temperature value. Step 2 proposes the Four Fourier calculation includes Fourier series and Fourier transform. Fourier series is a kind of trigonometric series, which is used to represent periodic functions. A periodic function is represented as a linear combination of a series of sine and cosine functions. Fourier transform converts a non-periodic continuous signal in the time domain into a non-periodic continuous signal in the frequency domain. The registers proposed in steps one and two are small storage areas for storing data, which are used to temporarily store the data and results of the operation. The storage circuit of the register is composed of an iron register or a trigger, which can be used to temporarily store instructions, data and addresses.

[0031] The above method can ensure that large power plants can provide sufficient active hot standby for load centers and meet the needs of reactive voltage support, so that sufficient reactive standby capacity can be formed at each load node and hub node during the operation of the power system, effectively avoiding the occurrence of malicious incidents of voltage collapse caused by lack of reactive power in the system, and ensuring the safe and stable operation of the power grid; through power failure monitoring, when the equipment encounters a power failure, the capacitor can be exited in time to ensure the integrity of the data within a certain time interval, and effectively avoid the adverse effects on the equipment caused by power failure; when the distribution network system is actually operating, the operating frequency of the power network system fluctuates above and below the rated frequency, showing a real-time change trend. While the system operating frequency is constantly changing, the sampling interval is adjusted in real time, and analog-to-digital information collection is carried out according to the updated sampling period, so as to ensure the accuracy of information sampling and analysis.

[0032] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0033] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A reactive power compensation control method for a power distribution network, characterized in that: The following steps are involved: Step 1: Information sampling, using PDB to control the frequency of analog-to-digital signal acquisition, setting the basic value of the parameter in the register, triggering the interrupt execution operation within the specified period, and sending it to the analog-to-digital conversion unit for sampling. After the sampling is successful, it triggers the direct memory access information acquisition and transmission, adopts its data access mode to transmit the corresponding acquisition information to the digital-to-analog conversion unit, and stores it in its memory data buffer address; Step 2: Sampling and analysis. Fourier calculation is performed for each frequency in the sampling address area. When the distribution network system is actually running, the operating frequency of the distribution network system fluctuates around the rated frequency, showing a real-time change trend. In order to achieve accurate information sampling and analysis, the sampling interval needs to be adjusted in time while the system operating frequency is constantly changing. After the collected information transmitted by the direct memory access unit meets the Fourier calculation requirements, the solution unit sends an instruction and the direct memory access unit stops transmitting. At this time, the frequency calculation value is used as the basis, and the parameters in the interrupt delay register are set again to ensure that the sampling of the analog-to-digital conversion unit meets the actual frequency requirements of the system. Then the direct memory access unit is started again to collect analog-to-digital information according to the updated sampling period. Step 3: Temperature rise analysis. Temperature rise analysis is one of the basic functions of the equipment's own protection control. The sensor measurement unit monitors the temperature rise and performs judgment according to the set threshold. When the temperature rise is higher than the threshold, the compensator is executed to lock out and all the compensators in operation are exited at the same time. Step 4: Operation analysis, select a reasonable adjustment strategy through information sampling, solve the appropriate compensator set, and in the power factor control process, give its objective function term, according to the voltage and current obtained by real-time sampling and the compensator control signal, give a reasonable compensation strategy after solving, and change the corresponding compensator state at the same time, so that the difference between the actual compensation amount and the required compensation amount is as small as possible. In the process of entering and exiting the compensator, use the optimal control method to find the most reasonable compensation strategy to achieve the effect of one-time compensation. Step 5: Power failure monitoring. When the equipment encounters a power failure, timely exit the capacitor to ensure data integrity within a certain time period.

2. A reactive power compensation control method for a power distribution network according to claim 1, characterized in that: The analog-to-digital conversion unit proposed in step 1 is used to convert the continuous changes of the analog signal into discrete digital values. The sampling is completed by discretizing the analog signal in time and then measuring the value of the signal within a specific time interval. The analog value obtained by sampling is divided into several levels, each level corresponds to a fixed digital value, and the quantized value is converted into a binary code for processing by the digital system.

3. A reactive power compensation control method for a power distribution network according to claim 1, characterized in that: The Fourier calculation proposed in the step 2 includes the frequency value, the voltage vector value of each phase and the voltage harmonic value of each phase up to the thirty-first order. The voltage harmonic value is generated when the harmonic current flows through the line impedance. The harmonic voltage is equal to the harmonic current multiplied by the grid impedance. The grid impedance includes the impedance of the transformer and the impedance of the distribution line. Harmonic refers to the component greater than the fundamental frequency after the periodic non-sinusoidal electrical quantity is decomposed by the Fourier series, except for the fundamental frequency component.

4. A reactive power compensation control method for a power distribution network according to claim 1, characterized in that: The compensator proposed in step three and step four includes a host and a slave, wherein the host is used to ensure that the slave has no competitive relationship with the host during normal operation, sends parameter reading instructions to the slave in sequence, checks and receives various parameter information sent back, including capacitance value, compensation type, switching signal, control type, temperature rise and threshold excess delay mark, samples voltage and current, and simultaneously calculates the real-time power flow of the system, including voltage, current and power value files, and calculates the power factor, voltage and current harmonic index values, samples the temperature sensor, and obtains the real-time temperature value.

5. A reactive power compensation control method for a power distribution network according to claim 4, characterized in that: The slave is used to check the status of the broadcast host. When no information is received within the set time interval, it starts the competition operation instruction, replaces the host after a given delay according to the local address information, checks the parameters sent by the host, reads the instructions, returns various parameter information, samples the voltage, and at the same time calculates the real-time voltage value of the system, samples the thermometer, and obtains the real-time temperature value.

6. A reactive power compensation control method for a power distribution network according to claim 1, characterized in that: The Fourier calculation proposed in step 2 includes Fourier series and Fourier transform. The Fourier series is a type of trigonometric series used to represent periodic functions, and a periodic function is represented as a linear combination of a series of sine and cosine functions. The Fourier transform converts a non-periodic continuous signal in the time domain into a non-periodic continuous signal in the frequency domain.

7. A reactive power compensation control method for a power distribution network according to claim 1, characterized in that: The registers mentioned in step 1 and step 2 are small storage areas for storing data, and are used to temporarily store data involved in calculations and calculation results. The storage circuit of the register is composed of an iron register or a trigger, and can be used to temporarily store instructions, data and addresses.

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