Optimal Power Sharing in a Meshed MTDC Grid Through Robust Current Flow Controllers

The two main challenges in meshed MTDC grids are protection from dc faults and managing the line power flows. In order to control the line power flow and the protection against dc faults DC current flow controllers can be used. The function of current flow controller is to control/balance the branch currents between the transmission lines in meshed multi-terminal HVDC grid system by increasing or decreasing the magnitude of the current as well as it is also possible to reverse the direction of current. However, the stability of the system may affect by the introduction of a DC current flow controller also increases the system size, overall cost, and complexity of the system. In this paper, the dynamic characteristics of the system with the introduction of a current flow controller on a four-terminal HVDC system have been discussed. The proposed scheme is simple and easily implemented and also it is very effective as it maintains the reliability security and stability of the system, whenever there is a change in load or if there is any fault in any line. To ensure proper power sharing and maintain the stability of the system time domain simulation is done on four terminals meshed MTDC grid in the presence of CFC by using MATLAB. The simulation result shows that the proposed system can effectively work by the introduction of a proposed optimal controller and application of current flow controllers which provide a solution to power flow issues in meshed MTDC grids.