Test device of power frequency voltage imposed with impulse voltage

Overvoltage accidents in distribution network account for 70%~80% accidents of the whole electrical power system. Overvoltage is usually superimposed on the power frequency voltage. To simulate the actual overvoltage situation in the electrical power system, a combined test platform of power frequency voltage imposed with overvoltage is established. The device consists of a power frequency voltage generating circuit, a impulse voltage generator, a automatic ignition device and a coupling capacitor. The impulse voltage generator consists of transformer, voltage regulator, non-reluctance resistor, capacitor, spark gap. The impulse overvoltage waveform can be adjusted according to the circuit parameters. Automatic ignition device consists of a voltage transformer, a comparator, a MCU (Micro Control Unit), a power amplifier and switching circuit, and a high voltage pulse generator. The automatic ignition device can ignite the spark gap automatically, and the phase of the power frequency voltage where the impulse voltage superimposed on can be controlled. The device has high reliability, good reproducibility and high flexibility. The device can be applied to on-line monitoring of insulation condition of underground cables and electrical equipments in distribution network.