Low-frequency Distortion Correction Technology of Rogowski Coil Applied to Lightning Current Measurement on Transmission Lines

When self-integrator Rogowski coil is used for measuring lightning current on transmission lines,because of the rich low-frequency component contained,the lightning current waveform measured often tends to be in low-frequency distortion,affecting the accurate measurement of lightning current parameters.Therefore,according to a theoretical analysis of the lowfrequency distortion mechanism of self-integrator Rogowski coil and an analysis of lightning current spectrum,a low-frequency distortion correction method based on a new integral compensation circuit is put forward for restoring the original measured current retroactively.The working principle of the circuit is also dealt with,and the circuit parameter value of each element is calculated based on electromagnetic parameters of Rogowski coil.Furthermore,the second-order high-pass filter circuit can be used to filter out the electromagnetic interference in Rogowski coil caused by the power frequency current.Experimental results show that the method is simple and feasible,the low-frequency response performance of self-integrator Rogowski coil is improved,the problem of low-frequency distortion of Rogowski coil used for measuring lightning current is solved.Adoption of the method for a transmission line lightning fault location system has effectively improved the measurement precision and reliability of the fault traveling wave current.