Transient stability enhancement control through VSC-HVDC system and fast frequency response resources

Abstract

In addition to the traditional long-distance and bulk power transmission application, the HVDC system can bring additional benefits to the system by providing ancillary service. The high-voltage direct-current transmission (HVDC) system can regulate its power flow in a very short time and can be used to provide emergency support to rescue the disturbed system from very bad conditions. However, because traditional generators cannot meet the great power demand of the HVDC system in a short time, the fast response of the HVDC system may cause severe power-unbalance events in the power supporting system. In this paper, a combination frequency response control (CFRC) is proposed for the fast frequency response (FFR) and HVDC system coordinating under the contingency. With the proposed combination frequency response control, the most use of the frequency response capacity of the HVDC system could be made. Meanwhile, the coordination between the HVDC system and fast frequency response could prevent the frequency of the power-source-provided system from dropping to an unacceptable level. The simulation study is conducted on a highly reduced power system model of the three North American interconnections. The simulation verification shows the effectiveness and feasibility of the proposed combination frequency response control and indicates that the frequency stability for both side systems of the HVDC system could be significantly improved with the proposed combination frequency response control. In the future, the communication delay between energy storage and HVDC will be considered in the strategy to further improve the accuracy of fast frequency response.