Application Cases

Experiment Name: Sensing Characteristic Tests of Voltage Sensors

Experiment Purpose: The proposed method for enhancing the frequency response of the inverse piezoelectric-grating voltage sensor aims to expand voltage sensing technology, providing new ideas for wide-frequency measurement of voltage signals and enriching the voltage sensing system. This method holds significant theoretical and practical value for promoting the application of voltage sensors based on piezoelectric materials and optical sensing technology in actual power grids.

Testing Equipment: High-voltage amplifier, oscilloscope, function waveform generator, capacitive voltage divider, voltage generator, etc.

Experiment Process:

Figure: Schematic Diagram of the Sensor Test Platform

A test platform for voltage sensor characteristics was built. The optical equipment mainly includes a C-band broadband light source and a photodetector, which are used to input broadband optical signals into the sensing system and to detect the intensity of the output optical signals from the sensor, respectively. The electrical equipment mainly includes a function waveform generator, high-voltage amplifier, capacitive voltage divider, small-scale impulse voltage generator, and oscilloscope, which are used to generate various voltage signals required for the sensor characteristic test and to collect test results and data.

In the laboratory, the arrangement shown in the figure above was used. The broadband optical signal from the broadband light source and the high-voltage signal output from the high-voltage amplifier were transmitted to the voltage sensor. After signal modulation by the sensor and light intensity detection by the photodetector, the light intensity was converted into voltage magnitude and transmitted to the oscilloscope via coaxial cables for display.

A 50Hz power frequency sine low-voltage signal was generated by the function waveform generator, amplified 500 times by the high-voltage amplifier, and used as the voltage signal to be measured, which was then output to the voltage sensing unit of the wideband inverse piezoelectric-grating voltage sensor. The output signals from the capacitive voltage divider and the wideband inverse piezoelectric-grating voltage sensor were both transmitted to the oscilloscope via coaxial cables for waveform display and data acquisition. The AC coupling mode was used to eliminate the influence of the DC voltage output by the photodetector. Figure 2 records the response of the voltage sensor to the voltage signal to be measured, where the upper blue curve represents the voltage signal to be measured, and the lower red curve represents the output response of the voltage sensor.

Figure 2: Response of the Voltage Sensor Under Power Frequency Voltage

Experimental Results:

From the figure above, it can be seen that there is good consistency between the voltage signal to be measured and the output response of the voltage sensor. The output response of the sensor can accurately follow the changes in the voltage signal to be measured, with a phase difference of less than 5.4°.

The input voltage signal to be measured was adjusted on the function waveform generator, starting from 0.25 kV and increasing the voltage signal to be measured in steps of 0.25 kV up to 4 kV. The amplitude of each applied voltage signal and the output signal of the sensor were recorded. The test results are shown in Figure 3.

Figure 3: Input-Output Characteristics of the Voltage Sensor

Figure 4: Fitting Results of Input-Output Characteristics

Linear fitting analysis was performed on the obtained data points. The parameters of the fitting curve, including the intercept C, slope k, and linear fitting degree R, are shown in Figure 4. The value of parameter C is 53 mV, the value of parameter k is 193.2941, and the linear fitting degree R is 0.9991. Here, k and C are fitting parameters related to the sensor's measurement sensitivity, and R represents the linear fitting degree, with values closer to 1 indicating a higher degree of fit.

Voltage Amplifier Recommendation: ATA-7050

Figure: Specification Parameters of the ATA-7050 High-Voltage Amplifier

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