Study On Partial Discharge Of Oscillating Wave Detection Equipment For Power Cable

XLPE cable has the advantages of superior electrical performance,easy laying and so on.It is widely used in current power network.With a large number of cables put into operation,there have been more and more cable fault problems,which are developed from the insulation defects.When there is an insulation defect in the cable,a partial discharge will occur in the defective part.Through the partial discharge measurement of the cable,you can find the insulation defects in the cables,avoid defects caused by cable insulation breakdown and the occurrence of electrical accidents,improve the reliability of cable operation.The traditional method of local discharge of cable has some problems,such as large volume of equipment,damage to cable and other problems.Oscillating wave detection method has been more and more recognized and applied,because the device is portable and the test results are good.There are some shortcomings in the charging method of oscillatory wave test equipment in domestic and abroad.In this paper,a new charging method is designed.On this basis,the oscillation wave detection equipment is designed for the cable field test.The main structure of the equipment includes the main circuit of the oscillation wave,the control circuit and the signal acquisition system.According to the actual requirements,the oscillation wave detection equipment is designed.Through the circuit simulation,the parameters of the various parts of the main circuit are determined.According to the parameters of the simulation,the main devices in the oscillating wave device are designed,including adjustable DC high voltage source,high voltage solid state switch,triggering control system and data acquisition sensor.The function of the DC high voltage source is to charge the capacitor in the device.Then,the capacitor charges the cable.The role of high-voltage solid-state switch is to achieve circuit conversion,from the state of charge to the oscillation state.Trigger control system is to achieve the conduction of high-voltage switch,which will switch at the same time.The data acquisition sensor realizesthe partial discharge information collection of the power cable.This paper introduces the advantages of the detection method used in the data acquisition system,which is designed by the laboratory.Finally,the actual circuit is built to verify the design of the oscillating wave equipment.Through the test results,we can see that the cable charging method used in this paper has the advantages of fast charging and little damage to the cable.Based on the partial discharge test under the defects of artificial cable,It is proved that the cable oscillation wave partial discharge detection equipment is feasible.High voltage solid state switch has a small size and easy to control.The trigger circuit has high reliability and strong anti-interference ability.The acquisition system can complete the partial discharge pulse current waveform-time(phase)acquisition.The design requirements of the system can be achieved.