Amplitude comparison based pilot protection for renewable power teed line

Fault behaviors of inverter-interfaced renewable energy generators (IIREGs) are quite diverse from those of synchronous generators (SGs). They show the variable system impedance, the limited current and low inertia, so the proportional brake differential protection installed on the transmission line has a high risk of failure for phase-phase failures. To cope with this adaptive problem, a new pilot protection was proposed considering huge difference in both current amplitudes. Also, an improved criterion is given for the scenario with a teed line. The existing protection principles focus on the fault current characteristics of IIREGs excessively, so they cannot operate correctly once IIREGs do not output the fault current. This happened when IIREGs produce no power or the circuit breaker exactly reclose on permanent failure. However, the proposed method has good performance for the above cases. The proposed method only requires current amplitude information, and in this case the strict synchronizing measurement is not necessary. Case studies are performed under different fault conditions, and they confirm the proposed method has good performance under different fault conditions. Furthermore, it is also verified using field-testing data.