Non-contact on-line overvoltage measurement system for overhead transmission line

Overhead transmission lines are easily disturbed by lightning overvoltages, which endangers the insulation performance of transmission lines. The overhead transmission line overvoltage measurement system based on the voltage divider has good accuracy. However, the long-term access of the voltage divider to the gird is easy to bring potential dangers to the power system. This paper proposed a non-contact, accurate, and real-time overvoltage measurement system to monitor the lightning overvoltages of the overhead transmission lines. The high voltage arm capacitor is composed of the overhead transmission line and the measurement electrode. The measurement electrode and the low voltage arm capacitors were integrated on a PCB board. The calibration and lightning overvoltage measurement experiment proved that the system had a broad bandwidth and excellent measurement accuracy. The non-contact overvoltage measurement system provided a new idea for overvoltage detection of the overhead transmission lines.

I. Introduction

The transient overvoltage mainly contains the switching overvoltage and lightning overvoltage, which is one of the main reasons that affect the safe operation of the power system. Therefore, accurate acquisition of transient overvoltage waveforms is helpful to optimize the insulation design of electrical equipment [1], [2].