WO2021082036A1 - Power system frequency measurement method, bus voltage correction method and devices - Google Patents
Power system frequency measurement method, bus voltage correction method and devices Download PDFInfo
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- WO2021082036A1 WO2021082036A1 PCT/CN2019/116037 CN2019116037W WO2021082036A1 WO 2021082036 A1 WO2021082036 A1 WO 2021082036A1 CN 2019116037 W CN2019116037 W CN 2019116037W WO 2021082036 A1 WO2021082036 A1 WO 2021082036A1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R23/00—Arrangements for measuring frequencies; Arrangements for analysing frequency spectra
- G01R23/02—Arrangements for measuring frequency, e.g. pulse repetition rate; Arrangements for measuring period of current or voltage
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/02—Measuring effective values, i.e. root-mean-square values
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- the invention relates to a power system frequency measurement method, a bus voltage correction method and a device, and belongs to the technical field of power system frequency measurement.
- Frequency is one of the important electrical parameters of the power system.
- the safety automatic device of the power system must measure its value in real time and make corresponding control measures according to the change of its value. Therefore, the accuracy of the frequency measurement directly affects the correct action of the safety automatic device. Sex.
- most of the safety automatic devices use the discrete Fourier transform method to calculate the frequency of the measured voltage. This algorithm is inherently insensitive to harmonic components. Although it can accurately measure the frequency of the power system under steady-state conditions, it is not sensitive to dynamic sudden changes. The changing signal will cause large measurement errors.
- the Chinese patent application with application publication number CN107064630A discloses a method and device for measuring power system frequency.
- the line voltage at three times is calculated by Fourier transform, and the real part and imaginary part of the line voltage at the three times are calculated according to the method and device.
- the current frequency of the calculation system is partially calculated.
- the purpose of the present invention is to provide a power system frequency measurement method and device, to solve the problem of large frequency error caused by frequency calculation using line voltage for a sudden change signal; the present invention also provides a bus voltage correction method and device, In order to solve the current lack of correction of the bus voltage.
- the measurement method includes the following steps:
- the present invention also provides a power system frequency measurement device.
- the measurement device includes a memory and a processor, and a computer program stored in the memory and running on the processor, and the processor is in phase with the memory. Coupled, the processor implements the power system frequency measurement method based on the positive sequence phase voltage of the present invention when the processor executes the computer program.
- the present invention uses the positive sequence phase voltage to calculate the frequency of the power system. Regardless of the angle error generated by the voltage analog quantity due to the sudden change in amplitude or the offset of the neutral point, the positive sequence component calculated by the three-phase voltage phasor synthesis can be used. Effectively offset the error and offset, so the frequency measurement method of the present invention is not affected by the voltage zero crossing point and harmonics. It can not only accurately measure the frequency of the power system under steady-state conditions, but also effectively solve the problem caused by voltage mutation. The problem of large frequency measurement error.
- the present invention also provides a specific calculation formula: the calculation formula used in the calculation frequency determination in step 3) is:
- f is the current frequency of the power system
- T s is the sampling interval time
- k is 1/P cycle
- U 1s (n) and U 1c (n) are the real and imaginary parts of the positive sequence voltage at the current moment
- U 1s (nk) and U 1c (nk) are the real and imaginary parts of the positive sequence voltage at the first 1/P cycle
- U 1s (n-2k) and U 1c (n-2k) are the first 2/P The real and imaginary parts of the positive sequence phase voltage at the time of the cycle.
- step B Determine whether the effective value of the bus voltage of each phase at the current moment obtained in step A is less than the first set voltage threshold, if both are less than the rated frequency of the power system as the current frequency of the power system; otherwise, according to the current bus
- the effective value of the voltage and the effective value of the busbar voltage at the previous cycle time determine whether the phase voltage has a sudden change. If it occurs, the frequency at the previous cycle time is used as the current frequency. If it does not occur, the calculated frequency in step 3) is used as the current frequency.
- the present invention also provides a formula for calculating the effective value of the phase voltage by the frequency tracking method, and the effective value of the bus voltage of each phase at the current moment is:
- U m is the effective value of the phase voltage at the current moment
- f is the calculated current frequency of the system
- f 0 is the system rated frequency 50 Hz
- n is the sampling sequence
- N is the number of sampling points per week for the power frequency sampling interval. Is the number of half-cycle sampling points of the current frequency of the system, u(nM) is the sine value of the sampling point half-cycle before the current frequency.
- the judgment principle of the sudden change of the phase voltage in step B is: the effective value of the bus voltage of any phase at the current moment and the effective value of the corresponding bus voltage at the previous cycle time
- the absolute value of the difference is greater than the second set threshold voltage value.
- the present invention also provides a method for correcting the bus voltage of a power system.
- the method includes the following steps:
- the effective value of the bus voltage of each phase is determined by the frequency tracking method at the current time to realize the correction of the bus voltage.
- the present invention also provides a correction device for bus voltage of a power system.
- the correction device includes a memory and a processor, and a computer program stored in the memory and running on the processor.
- the memory is coupled, and the method for correcting the bus voltage of the power system of the present invention is implemented when the processor executes the computer program.
- the present invention uses the positive sequence phase voltage to calculate the frequency of the power system. Regardless of the angle error generated by the voltage analog quantity due to the sudden change of the amplitude or the neutral point offset, the positive sequence component calculated by the three-phase voltage phasor synthesis can be used. It can effectively offset the errors and offsets, and can accurately measure the frequency of the power system under steady-state conditions, and realize the accurate calibration of the bus voltage according to the obtained frequency, and improve the accuracy of the bus voltage.
- the present invention also provides a formula for calculating the effective value of the phase voltage by the frequency tracking method, and the effective value of the bus voltage of each phase at the current moment is:
- U m is the effective value of the phase voltage at the current moment
- f is the calculated current frequency of the system
- f 0 is the system rated frequency
- n is the sampling sequence
- N is the number of sampling points per week in the power frequency sampling interval. Is the number of half-cycle sampling points of the current frequency of the system, u(nM) is the sine value of the sampling point half-cycle before the current frequency.
- calculation formula used to determine the calculation frequency in the step 3 is:
- f is the current frequency of the power system
- T s is the sampling interval time
- k is 1/P cycle
- U 1s (n) and U 1c (n) are the real and imaginary parts of the positive sequence voltage at the current moment
- U 1s (nk) and U 1c (nk) are the real and imaginary parts of the positive sequence voltage at the first 1/P cycle
- U 1s (n-2k) and U 1c (n-2k) are the first 2/P The real and imaginary parts of the positive sequence phase voltage at the time of the cycle.
- FIG. 1 is a comparison effect diagram of the error analysis of the frequency measurement of the present invention and the existing frequency measurement;
- FIG. 2 is a schematic diagram of the access position in the main wiring of the method embodiment of the present invention.
- Fig. 3 is a flow chart of the method for measuring the frequency of the power system based on the positive sequence phase voltage of the present invention.
- the present invention first uses the full-cycle Fourier algorithm to sequentially calculate the real and imaginary parts of the positive sequence voltage at the current time, the previous 1/P cycle time, and the previous 2/P cycle time.
- the calculation frequency of the system is calculated based on the real and imaginary parts of the positive sequence phase voltage at these three moments.
- a half-cycle integration algorithm with frequency tracking function is used to further calculate and correct the bus voltage analog quantity, and the obtained calculated frequency is error-proofed to further determine the current frequency.
- the access position of the main wiring in the power system of this embodiment is shown in Figure 2, and the specific implementation process is shown in Figure 3, and the specific steps are as follows.
- the full-cycle Fourier algorithm is used to sequentially calculate the real part of the three-phase voltage fundamental phasor at the current time, the previous 1/P cycle time, and the previous 2/P cycle time.
- the imaginary part where P is a positive integer, and P is greater than 1 and less than the number of sampling points of the weekly wave.
- the phase voltage is Calculate the real and imaginary parts of the fundamental phasor of the three-phase voltage:
- n is the sampling sequence
- N is the number of sampling points of a cycle at 50 Hz
- the real and imaginary parts of the fundamental phasor of the three-phase voltage at the three moments are synthesized and calculated.
- the calculation formula is as follows:
- the current system frequency can be obtained by comparing g 2p ( ⁇ ) and g p ( ⁇ ):
- T s is the sampling interval time.
- the basic principle of the discrete Fourier transform method for calculating frequency is to use the vector angle difference of the analog quantity to calculate the frequency.
- the smaller the angle error the higher the frequency measurement accuracy.
- the voltage analog quantity whether it is the angular error caused by the sudden change in amplitude or the offset of the neutral point, the positive sequence component calculated by the three-phase voltage phasor synthesis can effectively offset the error and offset. Therefore, the above measurement method is not affected by the voltage zero-crossing point and harmonics, not only can accurately measure the frequency of the power system under steady-state conditions, but also effectively solves the problem of large frequency measurement errors caused by voltage mutations.
- U m is the effective value
- T is the busbar voltage cycle.
- the voltage calculation formula of the half-cycle integral algorithm with frequency tracking function is as follows:
- U m is the effective value of the phase voltage at the current moment
- U 2m is the effective value of the phase voltage at the time one week ago
- f is the current frequency of the system
- f 0 is the system rated frequency 50Hz
- n is the sampling sequence
- N is the power frequency sampling interval Number of sampling points per week
- u(nM) is the sine value of the sampling point half a week before the current frequency
- u(n-2M) is the sine value of the sampling point one week before the current frequency.
- U max is the effective value of the three-phase maximum phase voltage
- U valve1 is the set first set voltage threshold (no voltage threshold), when the above-mentioned maximum phase voltage effective value is less than the set first set voltage threshold When the value is set, it is judged that the three-phase voltage of the bus bar has no voltage.
- U m is the effective value of the phase voltage at the current moment
- U 2m is the effective value of the phase voltage at the time one week ago
- U valve2 is the second set voltage threshold value set.
- the above formula represents the fundamental wave of the phase voltage at the current moment
- the absolute value of the difference between the amplitude and the fundamental wave amplitude of the line voltage before one week is greater than the set second voltage threshold, and it is determined that the bus voltage of any phase changes suddenly.
- the present invention uses the calculated value of the aforementioned power system frequency as the current time frequency only when the phase voltage does not change suddenly; when the phase voltage changes suddenly, the historical frequency at the time of the previous cycle is used as the frequency value measured at the current time. .
- the results obtained by the frequency measurement method of the present invention are compared with the results obtained by the existing line voltage frequency measurement.
- the bus three-phase voltage Under the condition of the system rated frequency of 50 Hz, the bus three-phase voltage
- the frequency measurement result of the positive sequence phase voltage adopted by the present invention is obviously better than the frequency measurement result based on the line voltage.
- the error range of the positive sequence frequency measurement of the phase voltage is 0.5Hz ⁇ 1Hz.
- the error range is 2Hz ⁇ 4Hz.
- the bus voltage correction method of this embodiment uses frequency tracking to determine the effective value of the bus voltage of each phase at the current time based on the current frequency obtained, and corrects the bus voltage. Among them, the current frequency is determined in the power system frequency measurement method embodiment. The detailed description will not be repeated here.
- the power system frequency measurement device of the present invention includes a memory and a processor, and a computer program stored in the memory and running on the processor, the processor is coupled with the memory, and the processor executes The computer program implements the above-mentioned power system frequency measurement method. The specific process has been described in detail in the method embodiment, and will not be repeated here.
- the device for correcting bus voltage of a power system of the present invention includes a memory and a processor, and a computer program stored in the memory and running on the processor, the processor is coupled with the memory, and the processing
- the above-mentioned power system frequency measurement method is implemented when the computer program is executed by the computer program. The specific process has been described in detail in the method embodiment, and will not be repeated here.
- this application can be provided as methods, systems, or computer program products. Therefore, this application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, this application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.
- This application is described with reference to flowcharts and/or block diagrams of methods, devices (systems), and computer program products according to embodiments of this application.
- each process and/or block in the flowchart and/or block diagram, and the combination of processes and/or blocks in the flowchart and/or block diagram can be implemented by computer program instructions.
- These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing equipment to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing equipment are generated It is a device that realizes the functions specified in one process or multiple processes in the flowchart and/or one block or multiple blocks in the block diagram.
- These computer program instructions can also be stored in a computer-readable memory that can guide a computer or other programmable data processing equipment to work in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture including the instruction device.
- the device implements the functions specified in one process or multiple processes in the flowchart and/or one block or multiple blocks in the block diagram.
- These computer program instructions can also be loaded on a computer or other programmable data processing equipment, so that a series of operation steps are executed on the computer or other programmable equipment to produce computer-implemented processing, so as to execute on the computer or other programmable equipment.
- the instructions provide steps for implementing the functions specified in one process or multiple processes in the flowchart and/or one block or multiple blocks in the block diagram.
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Abstract
The present invention relates to a power system frequency measurement method, a bus voltage correction method, and devices, belonging to the technical field of power system frequency measurement. In the present invention, a positive sequence phase voltage is used to calculate the frequency of a power system; for an angle error of a voltage analog quantity caused due to either magnitude flop or neutral point shift, all positive sequence components calculated by means of composition of three-phase voltage phasors can effectively counteract the error and shift therein. Therefore, the frequency measurement method of the present invention is not affected by a voltage zero-crossing point or a harmonic wave, not only being able to accurately measure the frequency of a power system in a steady state, but also effectively solving the problem of large frequency measurement errors caused by voltage jump.
Description
本发明涉及一种电力系统频率测量方法、母线电压校正方法及装置，属于电力系统频率测量技术领域。The invention relates to a power system frequency measurement method, a bus voltage correction method and a device, and belongs to the technical field of power system frequency measurement.
频率是电力系统的重要电气参数之一，电力系统安全自动装置要实时测量其值，并根据其值的变化做出相应的控制措施，因此对频率的测量精度直接影响了安全自动装置的动作正确性。目前安全自动装置大多采用对测量电压经离散傅里叶变换法计算频率，该算法具有内在的不敏感于谐波分量的特性，虽然能够准确测量稳态情况下电力系统的频率，但对于动态突然变化的信号会造成较大测量误差。Frequency is one of the important electrical parameters of the power system. The safety automatic device of the power system must measure its value in real time and make corresponding control measures according to the change of its value. Therefore, the accuracy of the frequency measurement directly affects the correct action of the safety automatic device. Sex. At present, most of the safety automatic devices use the discrete Fourier transform method to calculate the frequency of the measured voltage. This algorithm is inherently insensitive to harmonic components. Although it can accurately measure the frequency of the power system under steady-state conditions, it is not sensitive to dynamic sudden changes. The changing signal will cause large measurement errors.
例如，申请公布号为CN107064630A的中国专利申请，该专利公开了一种电力系统频率测量方法及装置，通过傅立叶变换计算三个时刻的线电压，并根据三个时刻的线电压的实部和虚部计算系统的当前频率，该方案虽然能够实现高精度的频率计算，但对突变信号仍会造成较大的测量误差。For example, the Chinese patent application with application publication number CN107064630A discloses a method and device for measuring power system frequency. The line voltage at three times is calculated by Fourier transform, and the real part and imaginary part of the line voltage at the three times are calculated according to the method and device. The current frequency of the calculation system is partially calculated. Although this solution can achieve high-precision frequency calculation, it will still cause large measurement errors for sudden changes.
发明内容Summary of the invention
本发明的目的是提供一种电力系统频率测量方法及装置，以解决对与突变信号采用线电压进行频率计算导致的频率误差大的问题；本发明还提供了一种母线电压校正方法及装置，以解决目前缺少对母线电压进行校正的问题。The purpose of the present invention is to provide a power system frequency measurement method and device, to solve the problem of large frequency error caused by frequency calculation using line voltage for a sudden change signal; the present invention also provides a bus voltage correction method and device, In order to solve the current lack of correction of the bus voltage.
本发明为解决上述技术问题而提供一种电力系统频率测量方法，该测量方法包括以下步骤：In order to solve the above technical problems, the present invention provides a power system frequency measurement method. The measurement method includes the following steps:
1)采集电力系统中接入的三相母线电压，通过傅立叶变换计算当前时刻、前1/P周波时刻、前2/P周波时刻的三相电压基波相量的实部和虚部，其中P为正整数，且P大于1小于每周波的采样点数；1) Collect the three-phase bus voltage connected in the power system, and calculate the real and imaginary parts of the three-phase voltage fundamental phasor at the current time, the previous 1/P cycle time, and the previous 2/P cycle time through Fourier transform, where P is a positive integer, and P is greater than 1 and less than the number of sampling points of the weekly wave;
2)根据得到各时刻的三相电压基波相量的实部和虚部，确定各时刻的正序相电压的实部和虚部；2) Determine the real and imaginary parts of the positive sequence phase voltage at each time according to the real and imaginary parts of the fundamental phasor of the three-phase voltage at each time;
3)根据各时刻的正序相电压的实部和虚部确定电力系统的计算频率，并根据该计算频率进一步确定当前频率。3) Determine the calculation frequency of the power system according to the real and imaginary parts of the positive sequence phase voltage at each time, and further determine the current frequency according to the calculation frequency.
本发明还提供了一种电力系统频率测量装置，该测量装置包括存储器和处理器，以及存储在所述存储器上并在所述处理器上运行的计算机程序，所述处理器与所述存储器相耦合，所述处理器执行所述计算机程序时实现本发明的基于正序相电压的电力系统频率测量方法。The present invention also provides a power system frequency measurement device. The measurement device includes a memory and a processor, and a computer program stored in the memory and running on the processor, and the processor is in phase with the memory. Coupled, the processor implements the power system frequency measurement method based on the positive sequence phase voltage of the present invention when the processor executes the computer program.
本发明采用正序相电压计算电力系统的频率，对于电压模拟量无论是由于幅值突变还是中性点偏移所产生的角度误差，由三相电压相量合成计算出的正序分量都可有效抵消其中的误差和偏移量，因此本发明的测频方法不受电压过零点和谐波的影响，不仅能够准确测量稳态情况下电力系统的频率，而且有效解决了由于电压突变引起的频率测量误差大的问题。The present invention uses the positive sequence phase voltage to calculate the frequency of the power system. Regardless of the angle error generated by the voltage analog quantity due to the sudden change in amplitude or the offset of the neutral point, the positive sequence component calculated by the three-phase voltage phasor synthesis can be used. Effectively offset the error and offset, so the frequency measurement method of the present invention is not affected by the voltage zero crossing point and harmonics. It can not only accurately measure the frequency of the power system under steady-state conditions, but also effectively solve the problem caused by voltage mutation. The problem of large frequency measurement error.
进一步地，本发明还给出了具体的计算公式：所述步骤3)中计算频率确定所采用的计算公式为：Further, the present invention also provides a specific calculation formula: the calculation formula used in the calculation frequency determination in step 3) is:
其中f为电力系统的当前频率，T
s为采样间隔时间，k为1/P周波，U
1s(n)和U
1c(n)分别为当前时刻正序相电压的实部和虚部，U
1s(n-k)和U
1c(n-k)分别为前1/P周波时刻正序相电压的实部和虚部，U
1s(n-2k)和U
1c(n-2k)分别为前2/P周波时刻正序相电压的实部和虚部。
Where f is the current frequency of the power system, T s is the sampling interval time, k is 1/P cycle, U 1s (n) and U 1c (n) are the real and imaginary parts of the positive sequence voltage at the current moment, U 1s (nk) and U 1c (nk) are the real and imaginary parts of the positive sequence voltage at the first 1/P cycle, respectively, U 1s (n-2k) and U 1c (n-2k) are the first 2/P The real and imaginary parts of the positive sequence phase voltage at the time of the cycle.
进一步地，为了提高频率测量的精准性，根据该计算频率确定当前频率的过程：Further, in order to improve the accuracy of frequency measurement, the process of determining the current frequency according to the calculated frequency:
A.根据得到计算频率利用频率跟踪方式确定当前时刻和前一周波时刻各相母线电压有效值；A. Use frequency tracking method to determine the effective value of the bus voltage of each phase at the current time and the previous cycle time according to the calculated frequency;
B.判断步骤A得到的当前时刻各相母线电压有效值是否均小于第一设定电压门槛值，若均小于，则以电力系统的额定频率作为电力系统的当前频率；否则，根据当前时刻母线电压有效值和前一周波时刻母线电压有效值判断相电压是否发生突变，若发生，则以前一周波时刻的频率作为当前频率，若没有发生，则以步骤3)中的计算频率作为当前频率。B. Determine whether the effective value of the bus voltage of each phase at the current moment obtained in step A is less than the first set voltage threshold, if both are less than the rated frequency of the power system as the current frequency of the power system; otherwise, according to the current bus The effective value of the voltage and the effective value of the busbar voltage at the previous cycle time determine whether the phase voltage has a sudden change. If it occurs, the frequency at the previous cycle time is used as the current frequency. If it does not occur, the calculated frequency in step 3) is used as the current frequency.
进一步地，本发明还给出了频率跟踪法计算相电压有效值的公式，所述当前时刻各相母线电压有效值为：Further, the present invention also provides a formula for calculating the effective value of the phase voltage by the frequency tracking method, and the effective value of the bus voltage of each phase at the current moment is:
其中，U
m为当前时刻相电压有效值，f为计算出的系统当前频率，f
0为系统额定频率50Hz，n为采样序列，N为工频采样间隔每周采样点数，
为系统当前频率的半周采样点数，u(n-M)为当前频率前半周前采样点正弦量值。
Among them, U m is the effective value of the phase voltage at the current moment, f is the calculated current frequency of the system, f 0 is the system rated frequency 50 Hz, n is the sampling sequence, and N is the number of sampling points per week for the power frequency sampling interval. Is the number of half-cycle sampling points of the current frequency of the system, u(nM) is the sine value of the sampling point half-cycle before the current frequency.
进一步地，为了保证相电压突变判断的精准性，所述的步骤B中的相电压发生突变的判断原则是：当前时刻任一相母线电压有效值与前一周波时刻对应相母线电压有效值之差的绝对值大于第二设定门槛电压值。Further, in order to ensure the accuracy of the judgment of the sudden change of the phase voltage, the judgment principle of the sudden change of the phase voltage in step B is: the effective value of the bus voltage of any phase at the current moment and the effective value of the corresponding bus voltage at the previous cycle time The absolute value of the difference is greater than the second set threshold voltage value.
本发明还提供了一种电力系统母线电压的校正方法，该校正方法包括以下步骤：The present invention also provides a method for correcting the bus voltage of a power system. The method includes the following steps:
1)采集电力系统中接入的三相母线电压，通过傅立叶变换计算当前时刻、前1/P周波时刻、前2/P周波时刻的三相电压基波相量的实部和虚部，其中P为正整数，且P大于1小于每周波的采样点数；1) Collect the three-phase bus voltage connected in the power system, and calculate the real and imaginary parts of the three-phase voltage fundamental phasor at the current time, the previous 1/P cycle time, and the previous 2/P cycle time through Fourier transform, where P is a positive integer, and P is greater than 1 and less than the number of sampling points of the weekly wave;
2)根据得到各时刻的三相电压基波相量的实部和虚部，确定各时刻的正序相电压的实部和虚部；2) Determine the real and imaginary parts of the positive sequence phase voltage at each time according to the real and imaginary parts of the fundamental phasor of the three-phase voltage at each time;
3)根据各时刻的正序相电压的实部和虚部确定电力系统的计算频率，并根 据该计算频率进一步确定当前频率；3) Determine the calculation frequency of the power system according to the real and imaginary parts of the positive sequence phase voltage at each time, and further determine the current frequency according to the calculation frequency;
4)根据得到当前频率利用频率跟踪方式确定当前时刻各相母线电压有效值，实现对母线电压的校正。4) According to the obtained current frequency, the effective value of the bus voltage of each phase is determined by the frequency tracking method at the current time to realize the correction of the bus voltage.
本发明还提供了一种电力系统母线电压的校正装置，该校正装置包括存储器和处理器，以及存储在所述存储器上并在所述处理器上运行的计算机程序，所述处理器与所述存储器相耦合，所述处理器执行所述计算机程序时实现本发明的电力系统母线电压的校正方法。The present invention also provides a correction device for bus voltage of a power system. The correction device includes a memory and a processor, and a computer program stored in the memory and running on the processor. The memory is coupled, and the method for correcting the bus voltage of the power system of the present invention is implemented when the processor executes the computer program.
本发明采用正序相电压计算电力系统的频率，对于电压模拟量无论是由于幅值突变还是中性点偏移所产生的角度误差，由三相电压相量合成计算出的正序分量都可有效抵消其中的误差和偏移量，能够准确测量稳态情况下电力系统的频率，并依据得到的频率实现对母线电压的精确校准，提高母线电压的准确性。The present invention uses the positive sequence phase voltage to calculate the frequency of the power system. Regardless of the angle error generated by the voltage analog quantity due to the sudden change of the amplitude or the neutral point offset, the positive sequence component calculated by the three-phase voltage phasor synthesis can be used. It can effectively offset the errors and offsets, and can accurately measure the frequency of the power system under steady-state conditions, and realize the accurate calibration of the bus voltage according to the obtained frequency, and improve the accuracy of the bus voltage.
进一步地，本发明还给出了频率跟踪法计算相电压有效值的公式，所述当前时刻各相母线电压有效值为：Further, the present invention also provides a formula for calculating the effective value of the phase voltage by the frequency tracking method, and the effective value of the bus voltage of each phase at the current moment is:
其中，U
m为当前时刻相电压有效值，f为计算出的系统当前频率，f
0为系统额定频率，n为采样序列，N为工频采样间隔每周采样点数，
为系统当前频率的半周采样点数，u(n-M)为当前频率前半周前采样点正弦量值。
Among them, U m is the effective value of the phase voltage at the current moment, f is the calculated current frequency of the system, f 0 is the system rated frequency, n is the sampling sequence, and N is the number of sampling points per week in the power frequency sampling interval. Is the number of half-cycle sampling points of the current frequency of the system, u(nM) is the sine value of the sampling point half-cycle before the current frequency.
进一步地，所述步骤3)中计算频率确定所采用的计算公式为：Further, the calculation formula used to determine the calculation frequency in the step 3) is:
其中f为电力系统的当前频率，T
s为采样间隔时间，k为1/P周波，U
1s(n)和U
1c(n)分别为当前时刻正序相电压的实部和虚部，U
1s(n-k)和U
1c(n-k)分别为前1/P周波时刻正序相电压的实部和虚部，U
1s(n-2k)和U
1c(n-2k)分别为前2/P周 波时刻正序相电压的实部和虚部。
Where f is the current frequency of the power system, T s is the sampling interval time, k is 1/P cycle, U 1s (n) and U 1c (n) are the real and imaginary parts of the positive sequence voltage at the current moment, U 1s (nk) and U 1c (nk) are the real and imaginary parts of the positive sequence voltage at the first 1/P cycle, respectively, U 1s (n-2k) and U 1c (n-2k) are the first 2/P The real and imaginary parts of the positive sequence phase voltage at the time of the cycle.
图1是本发明的频率测量与现有频率测量的误差分析对比效果图；FIG. 1 is a comparison effect diagram of the error analysis of the frequency measurement of the present invention and the existing frequency measurement;
图2是本发明方法实施例在主接线中的接入位置示意图；2 is a schematic diagram of the access position in the main wiring of the method embodiment of the present invention;
图3是本发明于正序相电压的电力系统频率测量方法的流程图。Fig. 3 is a flow chart of the method for measuring the frequency of the power system based on the positive sequence phase voltage of the present invention.
下面结合附图对本发明的具体实施方式作进一步地说明。The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.
本发明电力系统频率测量方法的实施例The embodiment of the method for measuring the frequency of the electric power system
本发明根据电力系统接入的三相母线电压模拟量，首先采用全周傅氏算法依次计算出当前时刻、前1/P周波时刻、前2/P周波时刻正序相电压的实部和虚部，根据这三个时刻正序相电压的实部和虚部计算出系统的计算频率。同时为了提高频率测量的精准性，还采用具有频率跟踪功能的半周积分算法进一步对母线电压模拟量进行计算和校正，对得到的计算频率进行了防错处理，进一步确定当前频率。本实施例电力系统中主接线的接入位置如图2所示，具体的实施过程如图3所示，具体步骤如下。According to the three-phase bus voltage analog quantity connected to the power system, the present invention first uses the full-cycle Fourier algorithm to sequentially calculate the real and imaginary parts of the positive sequence voltage at the current time, the previous 1/P cycle time, and the previous 2/P cycle time. The calculation frequency of the system is calculated based on the real and imaginary parts of the positive sequence phase voltage at these three moments. At the same time, in order to improve the accuracy of frequency measurement, a half-cycle integration algorithm with frequency tracking function is used to further calculate and correct the bus voltage analog quantity, and the obtained calculated frequency is error-proofed to further determine the current frequency. The access position of the main wiring in the power system of this embodiment is shown in Figure 2, and the specific implementation process is shown in Figure 3, and the specific steps are as follows.
1.确定三相电压基波相量的实部和虚部。1. Determine the real and imaginary parts of the fundamental phasor of the three-phase voltage.
根据电力系统中接入的三相母线电压模拟量，采用全周傅氏算法依次计算出当前时刻、前1/P周波时刻、前2/P周波时刻三相电压基波相量的实部和虚部，其中P为正整数，且P大于1小于每周波的采样点数。假设相电压为
计算三相电压基波相量的实部和虚部：
According to the three-phase bus voltage analog quantity connected in the power system, the full-cycle Fourier algorithm is used to sequentially calculate the real part of the three-phase voltage fundamental phasor at the current time, the previous 1/P cycle time, and the previous 2/P cycle time. The imaginary part, where P is a positive integer, and P is greater than 1 and less than the number of sampling points of the weekly wave. Suppose the phase voltage is Calculate the real and imaginary parts of the fundamental phasor of the three-phase voltage:
其中，n为采样序列，N为50Hz频率下一周波的采样点数，
依次代表A/B/C三相，
和
分别为当前时刻A/B/C三相电压基波相量的实部和虚部，
和
分别为1/P周波前A/B/C三相电压基波相量的实部和虚部，
和
分别为2/P周波前A/B/C三相电压基波相量的实部和虚部。
Among them, n is the sampling sequence, and N is the number of sampling points of a cycle at 50 Hz, Represents A/B/C three-phase in turn, with Are the real and imaginary parts of the fundamental phasor of A/B/C three-phase voltage at the current moment, with They are the real and imaginary parts of the A/B/C three-phase voltage fundamental phasor before 1/P cycle, with They are the real and imaginary parts of the A/B/C three-phase voltage fundamental phasor before 2/P cycles.
2.合成计算各时刻正序相电压的实部和虚部。2. Calculate the real and imaginary parts of the positive sequence phase voltage at each time by synthesis.
根据所述三个时刻的三相电压基波相量的实部和虚部，合成计算出三个时刻正序相电压的实部和虚部，其计算公式如下：According to the real and imaginary parts of the fundamental phasor of the three-phase voltage at the three moments, the real and imaginary parts of the positive sequence phase voltage at the three moments are synthesized and calculated. The calculation formula is as follows:
式中U
1c(n)和U
1s(n)分别为当前时刻正序电压的实部和虚部分量，
和
分别为1/P周波前正序电压的实部和虚部分量，
和
分别为2/P周波前正序电压的实部和虚部分量，其中α＝e
j2π/3。
Where U 1c (n) and U 1s (n) are the real and imaginary parts of the positive sequence voltage at the current moment, respectively, with Are the real and imaginary components of the positive sequence voltage before 1/P cycle, with They are the real and imaginary components of the positive sequence voltage before 2/P cycles, where α=e j2π/3 .
3.确定当前时刻计算频率。3. Determine the calculation frequency at the current moment.
本发明使用相电压正序分量进行频率测量，假设正序电压为u
1(n)＝U cos(nωT+φ)，经全周傅氏算法计算正序电压的实部和虚部：
The present invention uses the positive sequence component of the phase voltage for frequency measurement. Assuming that the positive sequence voltage is u 1 (n) = U cos(nωT+φ), the real and imaginary parts of the positive sequence voltage are calculated by the full-cycle Fourier algorithm:
由于滤波器
为偶对称，
为奇对称，所以：
Due to filter Is even symmetry, Is odd symmetry, so:
U
1c(n)＝|F
c(ω)|U cos(nωT
s+φ+α(ω))
U 1c (n)=|F c (ω)|U cos(nωT s +φ+α(ω))
U
1s(n)＝|F
s(ω)|U sin(nωT
s+φ+α(ω))
U 1s (n)=|F s (ω)|U sin(nωT s +φ+α(ω))
式中，|F
c(ω)|和|F
s(ω)|为偶、奇滤波器在ω处的增益，α(ω)为在ω处的相位变化；利用三角函数变换关系，进行如下变换：
In the formula, |F c (ω)| and |F s (ω)| are the gains of even and odd filters at ω, and α(ω) is the phase change at ω; using the trigonometric function transformation relationship, proceed as follows Transformation:
将g
2p(ω)和g
p(ω)进行比值可得当前系统频率：
The current system frequency can be obtained by comparing g 2p (ω) and g p (ω):
其中，T
s为采样间隔时间。
Among them, T s is the sampling interval time.
离散傅里叶变换法计算频率的根本原理是利用模拟量的矢量角度差来计算频率的，角度误差越小则测频精度越高。对于电压模拟量无论是由于幅值突变还是中性点偏移所产生的角度误差，由三相电压相量合成计算出的正序分量都可有效抵消其中的误差和偏移量。因此上述测量方法不受电压过零点和谐波的影响，不仅能够准确测量稳态情况下电力系统的频率，而且有效解决了由于电压突变引起的频率测量误差大的问题。The basic principle of the discrete Fourier transform method for calculating frequency is to use the vector angle difference of the analog quantity to calculate the frequency. The smaller the angle error, the higher the frequency measurement accuracy. Regarding the voltage analog quantity, whether it is the angular error caused by the sudden change in amplitude or the offset of the neutral point, the positive sequence component calculated by the three-phase voltage phasor synthesis can effectively offset the error and offset. Therefore, the above measurement method is not affected by the voltage zero-crossing point and harmonics, not only can accurately measure the frequency of the power system under steady-state conditions, but also effectively solves the problem of large frequency measurement errors caused by voltage mutations.
4.当电力系统各相电压均无压或电压突变时，需要对频率计算值进行相应的防错处理，过程如下：4. When the voltage of each phase of the power system has no voltage or the voltage changes suddenly, the frequency calculation value needs to be treated with corresponding error prevention. The process is as follows:
4.1由于上述三相电压基波相量是在电力系统额定频率50Hz的情况下采用全周傅氏算法得出，若系统实际频率偏离额定频率越大，则基波相量测量值误差越大，在计算出系统频率f后，需要使用具有频率跟踪功能的半周积分算法重新计算当前时刻和一周前各相母线电压有效值。假设相电压为
则在任意半周内对其绝对值的积分为：
4.1 Since the above-mentioned three-phase voltage fundamental phasor is obtained by the full-cycle Fourier algorithm under the power system rated frequency of 50 Hz, if the actual frequency of the system deviates from the rated frequency, the greater the error of the fundamental phasor measurement. After calculating the system frequency f, it is necessary to use the half-cycle integration algorithm with frequency tracking function to recalculate the effective value of the bus voltage at the current time and one week ago. Suppose the phase voltage is Then the integral of its absolute value in any half week is:
其中U
m为有效值，T为母线电压周期。
Among them U m is the effective value, T is the busbar voltage cycle.
采用分段梯形积分公式对上式进行离散，则具有频率跟踪功能的半周积分算法电压计算公式如下：Using the piecewise trapezoidal integral formula to discretize the above formula, the voltage calculation formula of the half-cycle integral algorithm with frequency tracking function is as follows:
式中U
m为当前时刻相电压有效值，U
2m为一周前时刻相电压有效值，f为系统当前的频率，f
0为系统额定频率50Hz，n为采样序列，N为工频采样间隔每周采样点数，
为系统当前频率的半周采样点数，u(n-M)为当前频率下半周前采样点正弦量值，u(n-2M)为当前频率前一周前采样点正弦量值。
Where U m is the effective value of the phase voltage at the current moment, U 2m is the effective value of the phase voltage at the time one week ago, f is the current frequency of the system, f 0 is the system rated frequency 50Hz, n is the sampling sequence, and N is the power frequency sampling interval Number of sampling points per week, Is the number of half-cycle sampling points of the current frequency of the system, u(nM) is the sine value of the sampling point half a week before the current frequency, u(n-2M) is the sine value of the sampling point one week before the current frequency.
4.2当电力系统各相电压均无压或电压突变时，需要对频率计算值进行相应的处理。4.2 When the voltage of each phase of the power system has no voltage or the voltage changes suddenly, the frequency calculation value needs to be processed accordingly.
(1)比较电力系统当前三相电压有效值，求出其中最大相电压的有效值，判断使用的三相电压是否存在无压的情况，判据如下：(1) Compare the effective value of the current three-phase voltage of the power system, find the effective value of the largest phase voltage, and judge whether there is no voltage in the three-phase voltage. The criteria are as follows:
U
max＜U
valve1
U max ＜U valve1
式中，U
max为三相最大相电压有效值，U
valve1为设定的第一设定电压门槛值(无压门槛)，当上述最大相电压有效值小于设定的第一设定电压门槛值时，判定母线三相电压无压。
In the formula, U max is the effective value of the three-phase maximum phase voltage, U valve1 is the set first set voltage threshold (no voltage threshold), when the above-mentioned maximum phase voltage effective value is less than the set first set voltage threshold When the value is set, it is judged that the three-phase voltage of the bus bar has no voltage.
(2)判别任一相母线电压是否发生突然变化。突然变化的判据如下：(2) Determine whether the bus voltage of any phase changes suddenly. The criteria for sudden changes are as follows:
|U
2m-U
m|＞U
valve2
|U 2m -U m |＞U valve2
式中，U
m为当前时刻相电压有效值，U
2m为一周前时刻相电压有效值，U
valve2为设定的第二设定电压门槛值，上式表示若当前时刻的相电压的基波幅值与一周前线电压的基波幅值之差的绝对值大于设定的第二电压门槛值，判定任一相母线电压发生突然变化。本发明只有在相电压没有发生突然变化时，才按照前述电力系统频率的计算值作为当前时刻频率；当相电压发生突然变化时，将前一周波时刻的历史频率做为当前时刻测量的频率值。
In the formula, U m is the effective value of the phase voltage at the current moment, U 2m is the effective value of the phase voltage at the time one week ago, and U valve2 is the second set voltage threshold value set. The above formula represents the fundamental wave of the phase voltage at the current moment The absolute value of the difference between the amplitude and the fundamental wave amplitude of the line voltage before one week is greater than the set second voltage threshold, and it is determined that the bus voltage of any phase changes suddenly. The present invention uses the calculated value of the aforementioned power system frequency as the current time frequency only when the phase voltage does not change suddenly; when the phase voltage changes suddenly, the historical frequency at the time of the previous cycle is used as the frequency value measured at the current time. .
为了证明本发明方案的可行性，将本发明的测频方法得到结果与现有采用线电压测频得到的结果进行比较，如图1所示，在系统额定频率50Hz情况下，母线三相电压由额定电压57.74V突变到18V时，本发明采用正序相电压的频率测量结果明显优于基于线电压的频率测量结果，相电压正序测频误差范围为0.5Hz～1Hz，线电压测频误差范围为2Hz～4Hz。In order to prove the feasibility of the scheme of the present invention, the results obtained by the frequency measurement method of the present invention are compared with the results obtained by the existing line voltage frequency measurement. As shown in Figure 1, under the condition of the system rated frequency of 50 Hz, the bus three-phase voltage When the rated voltage changes from 57.74V to 18V, the frequency measurement result of the positive sequence phase voltage adopted by the present invention is obviously better than the frequency measurement result based on the line voltage. The error range of the positive sequence frequency measurement of the phase voltage is 0.5Hz～1Hz. The error range is 2Hz～4Hz.
本发明电力系统母线电压的校正方法的实施例The embodiment of the method for correcting the bus voltage of the power system of the present invention
本实施例的母线电压校正方法根据得到当前频率利用频率跟踪方式确定当前时刻各相母线电压有效值，对母线电压的校正，其中，当前频率的确定已在电力系统频率测量方法实施例中进行了详细说明，这里不再赘述。The bus voltage correction method of this embodiment uses frequency tracking to determine the effective value of the bus voltage of each phase at the current time based on the current frequency obtained, and corrects the bus voltage. Among them, the current frequency is determined in the power system frequency measurement method embodiment. The detailed description will not be repeated here.
本发明电力系统频率测量装置的实施例Embodiment of the frequency measuring device of the power system of the present invention
本发明的电力系统频率测量装置，包括存储器和处理器，以及存储在所述存储器上并在所述处理器上运行的计算机程序，所述处理器与所述存储器相耦合，所述处理器执行所述计算机程序时实现上述电力系统频率测量方法，具体过程已在方法实施例中进行了详细说明，这里不再赘述。The power system frequency measurement device of the present invention includes a memory and a processor, and a computer program stored in the memory and running on the processor, the processor is coupled with the memory, and the processor executes The computer program implements the above-mentioned power system frequency measurement method. The specific process has been described in detail in the method embodiment, and will not be repeated here.
本发明电力系统母线电压的校正装置的实施例Embodiment of the device for correcting the bus voltage of the power system of the present invention
本发明的电力系统母线电压的校正装置，包括存储器和处理器，以及存储在 所述存储器上并在所述处理器上运行的计算机程序，所述处理器与所述存储器相耦合，所述处理器执行所述计算机程序时实现上述电力系统频率测量方法，具体过程已在方法实施例中进行了详细说明，这里不再赘述。The device for correcting bus voltage of a power system of the present invention includes a memory and a processor, and a computer program stored in the memory and running on the processor, the processor is coupled with the memory, and the processing The above-mentioned power system frequency measurement method is implemented when the computer program is executed by the computer program. The specific process has been described in detail in the method embodiment, and will not be repeated here.
本领域内的技术人员应明白，本申请的实施例可提供为方法、系统、或计算机程序产品。因此，本申请可采用完全硬件实施例、完全软件实施例、或结合软件和硬件方面的实施例的形式。而且，本申请可采用在一个或多个其中包含有计算机可用程序代码的计算机可用存储介质(包括但不限于磁盘存储器、CD-ROM、光学存储器等)上实施的计算机程序产品的形式。本申请是参照根据本申请实施例的方法、设备(系统)、和计算机程序产品的流程图和/或方框图来描述的。应理解可由计算机程序指令实现流程图和/或方框图中的每一流程和/或方框、以及流程图和/或方框图中的流程和/或方框的结合。可提供这些计算机程序指令到通用计算机、专用计算机、嵌入式处理机或其他可编程数据处理设备的处理器以产生一个机器，使得通过计算机或其他可编程数据处理设备的处理器执行的指令产生用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的装置。Those skilled in the art should understand that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, this application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, this application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes. This application is described with reference to flowcharts and/or block diagrams of methods, devices (systems), and computer program products according to embodiments of this application. It should be understood that each process and/or block in the flowchart and/or block diagram, and the combination of processes and/or blocks in the flowchart and/or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing equipment to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing equipment are generated It is a device that realizes the functions specified in one process or multiple processes in the flowchart and/or one block or multiple blocks in the block diagram.
这些计算机程序指令也可存储在能引导计算机或其他可编程数据处理设备以特定方式工作的计算机可读存储器中，使得存储在该计算机可读存储器中的指令产生包括指令装置的制造品，该指令装置实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能。这些计算机程序指令也可装载到计算机或其他可编程数据处理设备上，使得在计算机或其他可编程设备上执行一系列操作步骤以产生计算机实现的处理，从而在计算机或其他可编程设备上执行的指令提供用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的步骤。These computer program instructions can also be stored in a computer-readable memory that can guide a computer or other programmable data processing equipment to work in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture including the instruction device. The device implements the functions specified in one process or multiple processes in the flowchart and/or one block or multiple blocks in the block diagram. These computer program instructions can also be loaded on a computer or other programmable data processing equipment, so that a series of operation steps are executed on the computer or other programmable equipment to produce computer-implemented processing, so as to execute on the computer or other programmable equipment. The instructions provide steps for implementing the functions specified in one process or multiple processes in the flowchart and/or one block or multiple blocks in the block diagram.
最后应当说明的是：以上实施例仅用以说明本发明的技术方案而非对其限 制，尽管参照上述实施例对本发明进行了详细的说明，所属领域的普通技术人员应当理解：依然可以对本发明的具体实施方式进行修改或者等同替换，而未脱离本发明精神和范围的任何修改或者等同替换，其均应涵盖在本发明的权利要求保护范围之内。Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: Modifications or equivalent replacements of specific implementation manners without departing from the spirit and scope of the present invention shall be covered by the scope of protection of the claims of the present invention.
Claims (10)
- 一种电力系统频率测量方法，其特征在于，该测量方法包括以下步骤：A power system frequency measurement method, characterized in that the measurement method includes the following steps:1)采集电力系统中接入的三相母线电压，通过傅立叶变换计算当前时刻、前1/P周波时刻、前2/P周波时刻的三相电压基波相量的实部和虚部，其中P为正整数，且P大于1小于每周波的采样点数；1) Collect the three-phase bus voltage connected in the power system, and calculate the real and imaginary parts of the three-phase voltage fundamental phasor at the current time, the previous 1/P cycle time, and the previous 2/P cycle time through Fourier transform, where P is a positive integer, and P is greater than 1 and less than the number of sampling points of the weekly wave;2)根据得到各时刻的三相电压基波相量的实部和虚部，确定各时刻的正序相电压的实部和虚部；2) Determine the real and imaginary parts of the positive sequence phase voltage at each time according to the real and imaginary parts of the fundamental phasor of the three-phase voltage at each time;3)根据各时刻的正序相电压的实部和虚部确定电力系统的计算频率，并根据该计算频率进一步确定当前频率。3) Determine the calculation frequency of the power system according to the real and imaginary parts of the positive sequence phase voltage at each time, and further determine the current frequency according to the calculation frequency.
- 根据权利要求1所述的电力系统频率测量方法，其特征在于，所述步骤3)中计算频率确定所采用的计算公式为：The power system frequency measurement method according to claim 1, wherein the calculation formula used in the calculation of the frequency determination in the step 3) is:
其中f为电力系统的当前频率，T s为采样间隔时间，k为1/P周波，U 1s(n)和U 1c(n)分别为当前时刻正序相电压的实部和虚部，U 1s(n-k)和U 1c(n-k)分别为前1/P周波时刻正序相电压的实部和虚部，U 1s(n-2k)和U 1c(n-2k)分别为前2/P周波时刻正序相电压的实部和虚部。 Where f is the current frequency of the power system, T s is the sampling interval time, k is 1/P cycle, U 1s (n) and U 1c (n) are the real and imaginary parts of the positive sequence voltage at the current moment, U 1s (nk) and U 1c (nk) are the real and imaginary parts of the positive sequence voltage at the first 1/P cycle, respectively, U 1s (n-2k) and U 1c (n-2k) are the first 2/P The real and imaginary parts of the positive sequence phase voltage at the time of the cycle. - 根据权利要求1或2所述的电力系统频率测量方法，其特征在于，根据该计算频率确定当前频率的过程：The power system frequency measurement method according to claim 1 or 2, wherein the process of determining the current frequency according to the calculated frequency:A.根据得到计算频率利用频率跟踪方式确定当前时刻和前一周波时刻各相母线电压有效值；A. Use frequency tracking method to determine the effective value of the bus voltage of each phase at the current time and the previous cycle time according to the calculated frequency;B.判断步骤A得到的当前时刻各相母线电压有效值是否均小于第一设定电压门槛值，若均小于，则以电力系统的额定频率作为电力系统的当前频率；否则，根据当前时刻母线电压有效值和前一周波时刻母线电压有效值判断相电压是否 发生突变，若发生，则以前一周波时刻的频率作为当前频率，若没有发生，则以步骤3)中的计算频率作为当前频率。B. Determine whether the effective value of the bus voltage of each phase at the current moment obtained in step A is less than the first set voltage threshold, if both are less than the rated frequency of the power system as the current frequency of the power system; otherwise, according to the current bus The effective value of the voltage and the effective value of the busbar voltage at the previous cycle time determine whether the phase voltage has a sudden change. If it occurs, the frequency at the previous cycle time is used as the current frequency. If it does not occur, the calculated frequency in step 3) is used as the current frequency.
- 根据权利要求3所述的电力系统频率测量方法，其特征在于，所述当前时刻各相母线电压有效值为：The power system frequency measurement method according to claim 3, wherein the effective value of the bus voltage of each phase at the current moment is:
其中，U m为当前时刻相电压有效值，f为计算出的系统当前频率，f 0为系统额定频率，n为采样序列，N为工频采样间隔每周采样点数，为系统当前频率的半周采样点数，u(n-M)为当前频率前半周前采样点正弦量值。 Among them, U m is the effective value of the phase voltage at the current moment, f is the calculated current frequency of the system, f 0 is the system rated frequency, n is the sampling sequence, and N is the number of sampling points per week in the power frequency sampling interval.
Is the number of half-cycle sampling points of the current frequency of the system, u(nM) is the sine value of the sampling point half-cycle before the current frequency. - 根据权利要求3所述的电力系统频率测量方法，其特征在于，所述的步骤B中的相电压发生突变的判断原则是：当前时刻任一相母线电压有效值与前一周波时刻对应相母线电压有效值之差的绝对值大于第二设定门槛电压值。The power system frequency measurement method according to claim 3, characterized in that the principle for judging the sudden change of the phase voltage in the step B is: the effective value of the busbar voltage of any phase at the current moment corresponds to the phase busbar at the time of the previous cycle The absolute value of the difference between the voltage effective values is greater than the second set threshold voltage value.
- 一种电力系统频率测量装置，其特征在于，该测量装置包括存储器和处理器，以及存储在所述存储器上并在所述处理器上运行的计算机程序，所述处理器与所述存储器相耦合，所述处理器执行所述计算机程序时实现权利要求1-5中任一项所述的基于正序相电压的电力系统频率测量方法。A power system frequency measurement device, characterized in that the measurement device includes a memory and a processor, and a computer program stored in the memory and running on the processor, and the processor is coupled to the memory When the processor executes the computer program, the method for measuring the frequency of the power system based on the positive sequence phase voltage according to any one of claims 1 to 5 is implemented.
- 一种电力系统母线电压的校正方法，其特征在于，该校正方法包括以下步骤：A method for correcting bus voltage of a power system is characterized in that the method includes the following steps:1)采集电力系统中接入的三相母线电压，通过傅立叶变换计算当前时刻、前1/P周波时刻、前2/P周波时刻的三相电压基波相量的实部和虚部，其中P为正整数，且P大于1小于每周波的采样点数；1) Collect the three-phase bus voltage connected in the power system, and calculate the real and imaginary parts of the three-phase voltage fundamental phasor at the current time, the previous 1/P cycle time, and the previous 2/P cycle time through Fourier transform, where P is a positive integer, and P is greater than 1 and less than the number of sampling points of the weekly wave;2)根据得到各时刻的三相电压基波相量的实部和虚部，确定各时刻的正序相电压的实部和虚部；2) Determine the real and imaginary parts of the positive sequence phase voltage at each time according to the real and imaginary parts of the fundamental phasor of the three-phase voltage at each time;3)根据各时刻的正序相电压的实部和虚部确定电力系统的计算频率，并根 据该计算频率进一步确定当前频率；3) Determine the calculation frequency of the power system according to the real and imaginary parts of the positive sequence phase voltage at each time, and further determine the current frequency according to the calculation frequency;4)根据得到当前频率利用频率跟踪方式确定当前时刻各相母线电压有效值，实现对母线电压的校正。4) According to the obtained current frequency, the effective value of the bus voltage of each phase is determined by the frequency tracking method at the current time to realize the correction of the bus voltage.
- 根据权利要求7所述的电力系统母线电压的校正方法，其特征在于，所述当前时刻各相母线电压有效值为：The method for correcting the bus voltage of the power system according to claim 7, wherein the effective value of the bus voltage of each phase at the current moment is:
其中，U m为当前时刻相电压有效值，f为计算出的系统当前频率，f 0为系统额定频率，n为采样序列，N为工频采样间隔每周采样点数，为系统当前频率的半周采样点数，u(n-M)为当前频率前半周前采样点正弦量值。 Among them, U m is the effective value of the phase voltage at the current moment, f is the calculated current frequency of the system, f 0 is the system rated frequency, n is the sampling sequence, and N is the number of sampling points per week in the power frequency sampling interval.
Is the number of half-cycle sampling points of the current frequency of the system, u(nM) is the sine value of the sampling point half-cycle before the current frequency. - 根据权利要求7所述的电力系统母线电压的校正方法，其特征在于，所述步骤3)中计算频率确定所采用的计算公式为：The method for correcting the bus voltage of the power system according to claim 7, wherein the calculation formula used in the calculation of the frequency determination in the step 3) is:
其中f为电力系统的当前频率，T s为采样间隔时间，k为1/P周波，U 1s(n)和U 1c(n)分别为当前时刻正序相电压的实部和虚部，U 1s(n-k)和U 1c(n-k)分别为前1/P周波时刻正序相电压的实部和虚部，U 1s(n-2k)和U 1c(n-2k)分别为前2/P周波时刻正序相电压的实部和虚部。 Where f is the current frequency of the power system, T s is the sampling interval time, k is 1/P cycle, U 1s (n) and U 1c (n) are the real and imaginary parts of the positive sequence voltage at the current moment, U 1s (nk) and U 1c (nk) are the real and imaginary parts of the positive sequence voltage at the first 1/P cycle, respectively, U 1s (n-2k) and U 1c (n-2k) are the first 2/P The real and imaginary parts of the positive sequence phase voltage at the time of the cycle. - 一种电力系统母线电压的校正装置，其特征在于，该校正装置包括存储器和处理器，以及存储在所述存储器上并在所述处理器上运行的计算机程序，所述处理器与所述存储器相耦合，所述处理器执行所述计算机程序时实现权利要求7-9中任一项所述的电力系统母线电压的校正方法。A correction device for bus voltage of a power system, characterized in that the correction device includes a memory and a processor, and a computer program stored on the memory and running on the processor, the processor and the memory When the processor executes the computer program, the method for correcting the bus voltage of the power system according to any one of claims 7-9 is realized when the processor executes the computer program.
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| CN108896820A (en) * | 2018-07-19 | 2018-11-27 | 国电南京自动化股份有限公司 | It is a kind of suitable for static frequency changer starting phase modifier open machine protection phasor calculating method |
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