Performance evaluation of a four terminal HVDC systems for multi-directional power flow

This paper presents a configuration of multi-terminal VSC-HVDC transmission system, suitable for large offshore wind farms. The chosen multi-terminal arrangement consists of four terminals of which there are two wind farms, and the rest two are grid connections that can absorb different power, based on pre-arranged master-slave agreement (Fig.1). Various power flow conditions between grid terminals are tested to show the VSC reverse power capability of each grid side terminal. Strongly varied wind condition are tested, to evaluate the overall stability of the MTDC system. Adopted direct control system, in configuration with DC slack bus, is studied to avoid fast communication devices between the all terminals. The operation of the multi-terminal HVDC transmission system is examined through simulations using MATLAB®-SIMULINK®.