High Impedance Fault Identification in TCSC-Compensated Power Transmission Lines

The conventional distance relaying scheme performs poorly under the presence of Thyristors-controlled series capacitors “TCSC”, and during the high impedance fault “HIF”. TCSC provide a variable impedance during an internal/external fault and HIF is undetectable by the conventional overcurrent relaying due to low-current amplitude with non-linear behavior. Therefore, this paper presents a new Method for identifying the high impedance fault in TCSC-compensated transmission line. It is use the square error ration of the current signals during the fault period and current signals during the safe operating period for extracting the fault. The cumulative sum is being used for enlarging the fault features and then output index is obtained in order to perform the high impedance fault. The proposed method has been tested under different fault circumstances such as multiple fault locations, and multiple fault inception time. Moreover, fault happened nearby the terminal, power flow change, and faults in the presence of noise are also being considered. The test results have shown that the proposed method is good in term of time response, and then it is more appropriate for high impedance fault in TCSC-compensated power line.