Steady State Controll Strategy for a Meshed HVDC Grid with Wind Power Plants

Paper i proceeding, 2013

In this paper, a steady state control strategy, that can be used to ensure the stability (cable thermal power limit in this case) of a meshed HVDC grid consisting of wind power plants, is proposed. The control strategy involves power flow control. The objective of a power flow control in a DC grid, as in a point-to-point DC transmission, concerns controlling the DC voltage in the system within its limits and fulfilling the power input/output at the PCC (Point of Common Coupling) to the AC system, without exceeding maximum currents through the valves, lines or cables. The best power flow control can be achieved with the use of DC-DC converters in between the nodes of the meshed HVDC grid. However, the use of DC-DC converters in such a DC grid is quite costly, especially if implemented in an offshore environment. The main contribution of this paper is to demonstrate how the power flow in the DC grid, consisting of wind power plants, can be achieved without using DC-DC converters. Instead, it is achieved by controlling the bus power(s) injected into the DC grid, without curtailing the power from the wind power plants.