Role of HVDC Interconnection for Improving Frequency Response in a Low Inertia Power System

Abstract

The target of this research work is to investigate the role of High Voltage DC (HVDC) interconnection for enhancing frequency response in a low inertia grid. In recent times, installed capacity of wind and photovoltaic (PV) sources has significantly increased in South Australian power system. Most of these wind power plants deploy variable speed wind machines, whereas PV sources are predominantly distributed at consumer end. Therefore, wind power plants and PV generators in South Australia do not participate in frequency regulation. Under prolific penetration of wind and PV and considerable power ingress from adjoining system, an insignificant number of synchronous machines may be present in the South Australian network. During such condition, a big contingency (trip of an interconnection/a major generator) may result in unacceptable frequency response. Consequently, the network might face substantial under frequency load shedding. To mitigate this challenge, a solution for improving frequency response by taking into account the frequency control support from an HVDC interconnection is explored in this paper. To this end, a low inertia network, which mimics the South Australian grid, is analysed under various operating conditions.