Optimization Scheme for the SSC Discrimination Logic of Xinsong-Dongfang HVDC under Small Islanded Operation Mode

Abstract

The sending end of HVDC in islanded operation mode is a weak AC system, the security and stability control (SSC) system is very important for the operation of the islanded system. In this paper, the SSC strategy of Xinsong-Dongfang HVDC under islanded mode is deeply analyzed, and the defects and risks of the SSC discrimination logic for the small islanded operation mode is exposed during the RTDS simulation tests, as a result, some of the generators cannot be cut off. In addition, Then the research of the action sequence of SSC reveals the improper time coordination between the small islanded mode signal and the cut-off command. Based on the above work, an optimized scheme to discriminate the small islanded operation mode is proposed, and the correctness and effectiveness are verified through the same RTDS tests. This new method has great significance in the SSC design and implementation in HVDC transmission project with similar techniques.