Distributed Frequency Controller for MT-HVDC Systems Via Adaptive Dynamic Programming

The exact mathematical models of multi-terminal high-voltage direct current (MT-HVDC) systems are hard to be obtained in the practical application of HVDC technology. To overcome this challenge, a model-free distributed frequency controller for MT-HVDC systems is proposed based on Adaptive dynamic programming (ADP) in this paper. Specifically, for each AC area, only the local and neighboring sampling data of frequency is required without the MT-HVDC system model. Besides, the proposed controller is distributed which effectively balances the communication burden among the AC areas. Moreover, the proposed controller makes the connected AC areas share their power reserves via HVDC grids to compensate load disturbances so that the necessary power reserves can be downsized. Some simulations carried out on a five-terminal HVDC system evaluate the performance of the proposed controller.