Decoupling Methods for Transient Voltage Measurement of Transmission Line by Electro-Optical Field Sensor

Electro-optic field sensor (EOFS) provides a non-contact method to measure both the transient and steady state voltage of transmission line. However, coupling effect of electric field generated by three-phase voltage distorts the results. In this paper, two different methods are proposed using the parameter of steady state voltage compared with synchronous data from CVT. One way is solved the equations in frequency domain and the other way is in time domain. The methods were verified by field experiments in a UHV AC substation. The phase deviation and amplitude error of transient voltage during breaker operation process is corrected by applying the proposed methods. The time-domain method is affected dramatically by different sampling values and has poor performance for transient process. The frequency-domain method has better performance.