The resonant withstand voltage test method for the complete set ofvariable frequency series resonance test equipmentis to change the inductance and test frequency of the test system to make the circuit in a resonant state, so that most of the capacitive current on the test sample in the test circuit is offset by the inductive current on the reactor. The energy supplied by the power supply is only the working power consumed in the circuit, which is 1/Q of the capacity of the test sample (Q is the resonance multiple of the system), so the capacity of the test power supply is decreasing and the weight is greatly reduced.
The resonant withstand voltage test system of the complete set offrequency conversion series resonance test equipmentis divided into two types according to the adjustment method: inductive modulation (VISR) and frequency modulation (VFSR); The adjustable inductance type resonance test system can meet the withstand voltage requirements, but due to its large weight and poor mobility, it is mainly used in laboratories.
The voltage withstand test of the complete set offrequency conversion series resonance test equipmentuses the inductance of the reactor and the capacitance of the tested object to achieve capacitance resonance. Obtaining high voltage and high current on the test sample is a new method for high-voltage testing, which has been widely used both domestically and internationally.
The complete set offrequency conversion series resonance test equipmentis a resonant current filtering circuit, which can improve the waveform distortion of the power supply, obtain a better sine voltage waveform, and effectively prevent the accidental breakdown of the test sample by harmonic peaks; Variable frequency series resonance works in a resonant state. When the insulation point of the test sample is broken down, the current immediately becomes detuned, and the circuit current rapidly drops to one tenth of the normal test current.
When flashover breakdown occurs, due to the loss of resonance conditions, in addition to the immediate decrease in short-circuit current, the high voltage also disappears immediately, and the arc can be extinguished. The process of re establishing the recovery voltage is long, and it is easy to disconnect the power supply when the flashover voltage is reached again. Therefore, the frequency conversion resonance test system is suitable for insulation withstand voltage testing of high voltage and large capacity power equipment. It not only meets the withstand voltage requirements of high voltage XLPE cables, but also has the advantages of light weight and good mobility, making it suitable for on-site testing.
