A Reliable Accelerated Protection Scheme for Converter-Dominated Power Networks

Abstract

Communication assisted transfer trip schemes are generally preferred for transmission lines to provide reliable and accelerated protection from both ends. Dependability of such schemes on the performance of conventional distance and/or directional relays at both ends expresses a concern on their reliability in power systems with high penetration of converter-interfaced renewable sources. This work demonstrates the impact of converter-based sources on the available accelerated protection schemes and proposes a new transfer trip scheme mitigating the issue. The proposed method includes a new criteria to identify the fault direction in converter-dominated power networks using local voltage and current data. The scheme is tested for a modified WSCC 9-bus system with 100% converter-interfaced renewable penetration using PSCAD/ EMTDC and found to be reliable for different faults and system conditions.