Study on a New Power Frequency Capacitive Voltage Transducer for Gas Insulated Substations Based on Capacitive Voltage Division

The IVT for power frequency is an essential facility in the power system. Due to the requirement for high-voltage insulation, the sensing part of the conventional IVTs is bulky and costly. The purpose of this article is to propose a new voltage measurement method based on capacitive voltage divider for GIS. The equivalent circuit of the measurement method is built. The numerical simulation model for the measurement system is built based on the actual size of GIS with rated voltage of 220 kV. And FEM is employed to analyze the transfer relation and the accuracy of the proposed measurement method. The experiments are conducted in the laboratory and at an actual GIS platform, respectively. The transfer relation between the applied voltage and the induced voltage is obtained. Compared with conventional IVTs, the dimension of the measurement system is very small. Due to the low voltage of the sensing part, the insulation problem of the sensing part is avoided. And due to simple structure and linear characteristics, the transfer relation of the proposed measurement system can be obtained with high accuracy.

I. Introduction

The IVT plays an important role in the metering and protection systems in the power system [1]. With the development of the power system, voltage and power levels of the grid have increased rapidly [2], [3]. High voltage and large power capacity lead to larger dimension and higher cost of voltage transformers [4], [5]. For the traditional CVT, the high-voltage arm capacitance consists of many capacitors in series. In the CVTs with the rated voltage of 220 kV, hundreds of capacitors are needed to serve as the high-voltage arm capacitance. The complex structure would take up a large space and lead to serious insulation problems. A simple structure, small dimension, and low-cost voltage transformer has important applications in power system [6]–[8].