Distance Protection of Lines Emanating From Full-Scale Converter-Interfaced Renewable Energy Power Plants-Part II: Solution Description and Evaluation

Having unveiled the problems associated with distance protection of lines connected to full-scale converter-interfaced renewable energy power plants (CIREPPs) due to remote and intermediate infeed in Part I of this paper, Part II describes why the countermeasures currently deployed by commercial relays to tackle these problems in a conventional power system fail in the presence of a CIREPP. Then, a new formula to calculate impedance is devised for the phase element of the relay to prevent maloperation in the event of line-to-line to ground faults. In addition, a communication-assisted method with minimal bandwidth requirement is proposed for balanced and line-to-line faults. The issues that should be taken into consideration for single-line-to-ground faults are also discussed. The solutions presented in this paper are simple and independent of the host system grid code, and can be applied to industrial memory-polarized distance relays. A comprehensive performance evaluation is presented to verify the reliable operation of the proposed methods.