Improvement of post-fault voltage recovery performance under high renewable power penetration in a microgrid

Abstract

Blackouts, although rare, are considered as catastrophic incidents in power systems which can adversely affect day-to-day life. To combat this disastrous event, among many others, microgrids have emerged as a potential solution. This is mainly due to the capability of a microgrid to operate in an islanded mode after a large disturbance in the main grid, if necessary. However, even in an islanded microgrid, unacceptable voltage recovery performance after a fault may cause the cascading tripping of distributed generators (also known as Distributed Energy Resources – DERs). This may subsequently result in a blackout in a microgrid in extreme case. To enhance voltage control capability in microgrids, a number of research works are reported in the literature. However, these methods lack the capability of improving the post-fault voltage recovery performance at the Point of Common Coupling (PCC) of DERs in an islanded microgrid, especially under high renewable power penetration. Therefore, further investigations are still required to address this important research gap. To this end, Static VAR Compensator (SVC), which provides reactive power support, can be a worthwhile choice. In the above aspect, a methodology for the placement of SVC to improve the post-fault voltage recovery performance at the PCC of DERs under substantial renewable power penetration in a microgrid is proposed in this thesis. Also, the impact of load model parameters on the voltage recovery performance at the PCC of DERs following a severe fault in a microgrid is explored. The proposed methodology is applied to a test microgrid network under various renewable power penetration scenarios. The effectiveness of the developed technique is validated by comparing its performance with that an existing method. The findings of this research work provide significant insight into the capability of the SVC to improve post-fault voltage recovery performance in an islanded microgrid with high renewable power penetration. Eventually, the developed approach mitigates the risk of cascading tripping of DERs and subsequent blackout to ensure resilient operation of a microgrid.