Application of Lightning Impulse Voltage Waveform Simulation

Author： GOZ Electric Time：2024-09-09 09:48:23 Read：9

Lightning impulse test is an important item in withstand voltage and insulation test, and is an important basis for judging whether electrical equipment meets high-voltage working requirements. In order to facilitate quantitative adjustment of the parameters of impulse voltage waveform, this paper establishes a simulation model of lightning impulse voltage generator based on simulink platform, and uses 1600kV/80kj lightning impulse voltage generator for verification. Experimental results show that the consistency error between the voltage peak value Um, wavefront time T1 and half-peak time T2 of the simulated waveform and the actual waveform does not exceed ±3%, which can quickly and accurately adjust the key parameters of impulse voltage waveform, improve daily experimental efficiency, and assist in the operation and maintenance management of experimental equipment.

Keywords: lightning impulse experiment; simulink simulation; wavefront time; half-peak time

In the process of operation, electrical equipment may be attacked by temporary overvoltage and lightning overvoltage in addition to the working voltage. The laboratory generally uses the impulse voltage generated by the impulse voltage generator to simulate the overvoltage caused by lightning discharge to realize the insulation detection of high-voltage electrical equipment. The destructive effect of impulse voltage is related to the waveform, amplitude, and waveform steepness, which are mainly reflected in key parameters such as peak voltage, wavefront time, and half-peak time. my country's current standards have strict regulations on the waveform of lightning impulse test: the wavefront time of lightning impulse voltage is required to be 1.2μs, the relative error does not exceed ±30%, and the half-peak time is 50μs, and the relative error does not exceed ±20%. Due to the inductance of the test product, it is generally impossible to obtain a unipolar standard full-wave voltage, and there will be zero-crossing oscillations at the tail of the wave. Therefore, the oscillation reverse peak value is required not to exceed 50% of the applied voltage amplitude.

The voltage level of the impulse voltage experiment is high and the operation is complex. Especially when conducting experiments on different test products, the waveform characteristics (including parameters such as Um, T1, and T2) need to be adjusted. However, in the laboratory, this process has high requirements for operators, and it is necessary to go through "adjustment-experiment" repeatedly many times before the impulse voltage generator can output a waveform that meets the requirements. Based on simulink, this paper establishes a simulation model of the impulse voltage waveform generator set, which can be used for efficient and accurate adjustment of the impulse voltage waveform generator, improving the experimental efficiency.

Figure 1

Figure 2

Experimental process omitted

This paper proposes a simulation model suitable for lightning impulse experiments. According to the test requirements of the test product, the wavefront resistance value and wave tail resistance value of the impulse voltage generator can be calculated through the simulation model, and before the insulation test of the equipment, the output impulse voltage waveform can be simulated to achieve efficient and accurate adjustment of the impulse voltage generator, which not only improves the efficiency of daily experiments, but also assists the operation and maintenance management of experimental equipment.