Travelling wave fault location principle based on Rogowski coil's differential output and Hilbert-Huang transform

Travelling wave fault location method has been used in power system, but its performance was affected by the frequency band limitation (<100kHz) of traditional current transformer (CT). As a new kind of transducer, Rogowski coil based electronic current transformer (R-ECT) has wide frequency bandwidth (several Hz to 1MHz) and differential output characteristic. Hilbert-Huang transform (HHT) is an analysis method for irregular signal and it can identify the mutation point of differential travelling wave precisely. Based on the instantaneous amplitude of differential travelling wave's Hilbert-Huang transform, the paper constructs new wave front identification criteria used in fault location method. Considering different fault locations and fault types, a 500kV power system simulation is carried out in PSCAD and the results prove the high accuracy of proposed fault location principle. To verify the fault location simulation, an experiment system is established using travelling wave signal generator, data acquisition device and Rogowski coil. The experiment result confirms the feasibility of fault location method.