Design of Grid Forming Inverter for Integration of Large-Scale Wind Farm in Weak Grid

Abstract

The current Australian electricity networks are being augmented with large numbers of inexhaustible renewable energy resources (inverter-based asynchronous generators). This integration is weakening (low inertia and system strength) the national electricity grid due to the lack of synchronous generations. A weaker grid often causes low-frequency oscillations, and voltage instability, and hampers voltage ride-through capabilities of renewable resource-based asynchronous generators. Synchronous Condensers (SC) can eventually overcome these limitations of weaker grids. However, the SC is not favorable to the power plant developers due to its higher capital and operating costs, longer lead time (at least 2 years), transportation complexities to the remote wind/solar farm locations and no opportunities for revenue structuring. Therefore, Grid Forming (GFM) inverter technologies are becoming popular for overcoming the complexities of renewable energy resources integrations into weaker grids. This paper presents the dynamic performance of a GFM inverter for integrating a large-scale wind farm in a weak grid. A 100 MW wind farm with a 25 MVA GFM inverter has been developed in PSCAD/EMTDC environment. The effectiveness of the proposed system has been verified through the simulation results under different test conditions.