Development of models to study VSC response to AC system faults and the potential impact on network protection

As the utilization of renewable energy sources (RES) and HVDC links is growing rapidly, many characteristics of the resulting power system can be seriously changed. HVDC links, as well as RES using converters as an interface with the main grid, can be all treated as non-synchronous sources. These sources are different from the traditional synchronous generators in many ways and bring significant challenges to the existing protection systems. Therefore, the aim of this paper is to explore power system protection performance issues under the context of the main characteristics of future power networks. In this paper the operating principles of converters is investigated. Initial equivalent models of Voltage Source Converters (VSC) in response to both symmetrical and unsymmetrical faults in the AC power systems are introduced and developed. Such models explain the characteristics of the future power networks with focuses on protection system performance. The VSC models will investigate system performance under fault conditions taking into account of European HVDC Grid Code requirements proposed by the European Network of Transmission System Operators for Electricity (ENTSO-E)[1].