Development Of High Voltage Oscillating Wave Generator For Cable Field Test

With the large scale construction and upgrade of urban power network,XPLE power cables have been widely used in the urban medium voltage power supply network. Traditional cable field test methods can cause damage to cables and corresponding testing equipments are of large volume. But oscillating wave testing method has a good application prospect for its good testing result and equipment portability.In this paper, firstly the characteristics of various withstand voltage tests and partial discharge tests for power cables and the development status of oscillating wave testing method are discussed. Then the high voltage oscillating wave generator for cable field test is developed, including the main circuit, control circuit, signal acquisition circuit and software control system.In this paper, the structure of high voltage oscillating wave generator is designed according to its system parameter requirements. The cable charging mode and air core reactor parameters are chosen by analyzing and simulating the constant voltage, constant current charging process and the oscillating discharge process of cables.The DC high voltage generator, solid state high voltage switch and lower computer control system are designed. The DC high voltage generator controls the constant current charging process of cables. The solid state high voltage switch can change main circuit state between constant current charging mode and oscillating discharge mode. The lower computer control system can control the DC high voltage generator and solid state high voltage switch.Based on VC++6.0 and keil software platform, the software programming of upper computer control system and lower computer control system are carried out.The upper computer control program includes human-computer interaction,partial discharge signal acquisition, lower computer monitoring and workprocess recording functions. By controlling the DC high voltage generator and solid state high-voltage switch, the lower computer program can control constant current charging process and the oscillating discharge process of cables.The system software and hardware are debugged in detail. According to the debugging results, the DC high voltage generator can finish the cable constant current charging process rapidly and smoothly. The solid state high voltage switch has the advantage of small volume and is easy to control. The upper computer control system can achieve dual channel signal acquisition and oscillating discharge process control. Debugging results show that the system meets the design requirement.