Application Cases

Experimental Name: Partial Discharge Test under Superimposed Harmonic DC Voltage

Test Equipment: High-voltage amplifier, oscilloscope, waveform generator, high-frequency current transformer, etc.

Figure 1: Partial Discharge Test Setup under Superimposed Harmonic DC Voltage

Experimental Process:
Figure 1 shows the harmonic voltage generation and partial discharge measurement setup. First, a low-voltage waveform is generated by the waveform generator, then amplified to the test voltage level through the high-voltage amplifier. This voltage is applied to the insulated air-gap discharge sample for partial discharge measurement. The insulation sample contains an air-gap defect with a radius of 0.6 mm. During the test, the maximum rise rate of the amplifier's voltage output is 214 V/μs. A high-frequency current transformer (HFCT) is used to measure the partial discharge characteristics of the defect. The high-voltage amplifier can amplify the input low voltage by a factor of 2000, facilitating the generation of test voltages with DC superimposed harmonics. Partial discharge data is recorded by the oscilloscope at a sampling rate of 250 MS/s.

Experimental Results:

Figure 2: Partial Discharge Measurement Results under Superimposed Harmonic Voltage

Using the test setup shown in Figure 1, partial discharge tests under superimposed harmonic DC voltage were conducted. The test results are presented in Figures 2(a-c).

Figures 2(a-c) show the discharge behavior of the insulated air gap under superimposed harmonic high-voltage DC. Figure (a) displays cumulative discharge data from the discharge initiation time (recorded as 0 s) up to 9 s. It can be observed that discharges predominantly occur near the positive peaks of the voltage harmonics. Figure (b) shows cumulative discharge data over 70 s, where the number of partial discharge pulses continues to increase as the number of harmonic cycles rises. Figure (c) presents cumulative discharge data over 202 s, where partial discharge pulses near the positive peaks of the harmonics become more pronounced, and the number of discharges increases further.

Comparing Figures 2(a-c), it is evident that as the experiment progresses, the number of partial discharges increases, and the discharge characteristics become more distinct, primarily concentrated near the positive peaks of the applied voltage harmonics.

High-Voltage Amplifier Recommendation: ATA-7100 High-Voltage Amplifier

Figure: ATA-7100 High-Voltage Amplifier Specifications and Parameters

Xi'an Aigtek Electronics is a high-tech enterprise specializing in the research, development, production, and sales of electronic measurement instruments, including power amplifiers, high-voltage amplifiers, power signal sources, preamplifiers for weak signals, high-precision voltage sources, and high-precision current sources, providing users with competitive testing solutions. Aigtek has become a large-scale instrument supplier with a wide range of product lines in the industry, and demo units are available for free trial.