Start-Up Control of a Synchronous Condenser Integrated HVDC System With Power Electronics Based Static Frequency Converter

The operation of thyristor-based high-voltage direct current (HVDC) system requires abundant reactive power support. Synchronous condensers, as rotating devices with large capacity of reactive power compensation, are generally utilized in HVDC systems. In this paper, the start-up control of a synchronous condenser integrated HVDC system with power electronics based static frequency converter (SFC) is investigated with the following 3 contributions: (1) Three different variable frequency starting methods are proposed regarding the main start-up control component, SFC. (2) Dynamic behaviors of AC voltages, reactive power of the system are studied when the synchronous condenser is integrated into the HVDC with different start-up control methods. An evaluation index, including successive rates of integration, reactive power surges, and lengths of start-up period, are established using different start-up control methods. (3) Synthesizing the characteristics of three different start-up control methods, an optimized variable frequency starting control is proposed and the control strategy is further developed. A simulation model of a synchronous condenser integrated HVDC system with an SFC is established in PSCAD/EMTDC. Simulation results justify the effectiveness and superiority of the optimized start-up control strategy proposed.