| A current sensor is the key equipment for the current collection of the intelligent substation.It is mainly used for the collection of the primary bus current,and the converted voltage or current value is transmitted to the power quality measurement system to realize the measurement and analysis of the power quality.In order to ensure the accuracy of electric energy measurement and power system analysis,the current sensor must always be in an accurate and stable working state.Therefore,it is very important to test its performance regularly.In this paper,under the funding of the scientific research project "Current Sensor Online Detection Method Research" of Hunan Institute of Metrology and Inspection,the research on the current sensor online detection method is carried out for the detection problem of current sensor.The specific research content is as follows:By analyzing the shortcomings of Fast Fourier Transform(FFT)in the current sensor detection process,a current sensor online detection method based on time-shifting and windowed FFT is proposed,and the overall model of the detection system is established to realize the current The frequency,amplitude and phase of the sensor output signal are calculated,and the parameters of the primary side input signal are obtained under the condition that the parameters of the standard current sensor are known,and the actual transformation ratio and phase shift of the current sensor to be tested are finally detected.The simulation experiment verifies the accuracy of the method.By analyzing the mathematical principles of the correlation detection method and the working characteristics of the current sensor,a current sensor online detection method based on the correlation detection method is proposed,and the overall model of the detection system is established,using the correlation between the output signal of the current sensor under test and the standard current sensor,The calculation of the amplitude and phase of the output signal of the current sensor under test is completed,and the actual transformation ratio and phase shift of the current sensor under test are finally detected.The simulation experiment verifies the accuracy of the method.A current sensor online detection system based on time-shifting and windowed FFT is designed,which is mainly composed of a standard current sensor,a data acquisition card,and an industrial computer.The digital acquisition card converts the output signals of the current sensor to be measured and the standard current sensor into digital signals,and then transmits them to the industrial computer,calls the algorithm to complete the calculation of the signal parameters,and finally realizes the detection of the current sensor to be measured;a related detection method is designed The current sensor online detection system is mainly composed of a standard current sensor,a signal conditioning circuit,a phase lock amplifying circuit,and a microprocessor.After the output signals of the current sensor under test and the standard current sensor are processed by the conditioning circuit,the signal correlation is realized in the phaselocked amplifier circuit,and the output analog voltage is converted into a digital signal by the sampling circuit,and the microprocessor receives the data and completes the calculation of the parameters.Using the detection system for testing,the experimental results show that the online detection system designed in this paper can effectively detect the accuracy and the accuracy of harmonics of the current sensor. |
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