Frequency Emergency Control for Large-scale Disconnection of Renewable Energy

Abstract

With the development of ultra high voltage direct current (UHVDC) and the continuous increase proportion of renewable energy (RE), it has strongly supported Chinese energy transformation strategy. However, due to the poor dynamic performance of RE generation under grid fault, in the DC sending power grid where RE is centrally connected, AC and DC faults can easily cause large-scale disconnection of RE, which brings to a great challenge to the power system transient frequency security. In this paper the process of large-scale disconnection of RE in the UHVDC sending grid is first analyzed. Then the frequency emergency control scheme triggered by the event information such as DC commutation failure is designed according to fault process analysis. Finally, a simulation example of the Northwest China Power Grid is built to verify that the proposed frequency emergency control strategy can effectively deal with the problem of large-scale disconnection of RE caused by AC and DC faults, and can greatly improve the UHVDC transmission capacity and RE generation of the power grid.