AC Power Flow Control with a Multiterminal DC System

The scheduling of the power transfers of a multiterminaL dc network to control the power distribution in certain ac lines of an ac-dc system requires coordination. With the new method presented in this paper, the coordination of the dc network´s power transfers is simplified considerably to that of solving a linear matrix equation of order one Less than the number of converter terminals. The Losses, as well as the power limits of the converters, in the dc network are considered in the method of coordination. This method of coordination is combined with a standard ac-dc load-fLow, whose purpose is to estabLish the resuLtant operating point of the ac-dc system, to form an algorithm for scheduling the dc network´s power transfers to control the power distribution in certain ac lines of an ac-dc system. The tests performed on a 5 dc terminaL, 30 ac bus, sample system showed that the power flows, close to the desired values, in a number of the ac Lines could be simultaneously obtained with just one iteration of the proposed algorithm. The algorithm proved to be efficient and effective in these tests. The algorithm can be used to plan dc network reinforcements to an ac network and is potentially suitable for the on-line application of networK flow control.