Multi-Phase EMTR-based Fault Location Method Using Direct Convolution Considering Frequency-Dependent Parameters and Lossy Ground

Many Electromagnetic time reversal (EMTR)-based fault location methods were proposed in the latest decade. In this paper, we briefly review the EMTR-based fault location method using direct convolution (EMTR-conv) and generalize it to multi-phase transmission lines. Moreover, noting that the parameters of real transmission lines are frequency-dependent, while constant-parameters were often used during the reverse process of EMTR-based methods in the previous studies, we investigate the influence of this simplification to the fault location performance by considering frequency-dependent parameters and lossy ground in the forward process which shows the location error increases as the distance between the observation point and the fault position increases, especially when the ground resistivity is high. Therefore, we propose a correction method to reduce the location error by using double observation points. Numerical experiments are carried out in a 3-phase 300-km transmission line considering different ground resistivities, fault types and fault conditions, which shows the method gives good location errors and works efficiently via direct convolution of the signals collected from the fault and the pre-stored calculated transient signals.

A Fault Location Method Using Direct Convolution: Electromagnetic Time Reversal or Not Reversal

Electromagnetic time reversal (EMTR) is drawing increasing interest in short-circuit fault location. In this letter, we investigate the classic EMTR fault location methods and find that it is not necessary to reverse the obtained signal in time which is a standard operation in these methods before injecting it into the network. The effectiveness of EMTR fault location method results from the specific similarity of the transfer functions in the forward and reverse processes. Therefore, we can inject an arbitrary type and length of source in the reverse process to locate the fault. Based on this observation, we propose a new EMTR fault location method using direct convolution. This method is different from the traditional methods, and it only needs to pre-calculate the assumed fault transients for a given network, which can be stored in embedded hardware. The faults can be located efficiently via direct convolution of the signal collected from a fault and the pre-stored calculated transients, even using a fraction of the fault signal.