Supervisory Control Of On-Load Tap-Changing Transformers In Xiamen Bipole Vsc-Hvdc Transmission Demonstration Project

In the framework of discrete-event systems, supervisory control of transformers in Xiamen bipole Voltage Source Converter based High Voltage Direct Current Transmission (VSC-HVDC) project is studied. An on-load tap changing transformer is a typical discrete-event system, which its behavior is event-driven rather than time-driven and its states (the location of the tap) are discrete. In Xiamen bipole VSC-HVDC project, the on-load tap-changing transformer can be controlled either automatically or manually. For manually pattern, the operating are made by operator and do not need a controller. So, this paper discusses the automatically control pattern. This paper considers an on-load tap-changing transformer as a discrete-event system. The on-load tap-changing transformer and its specifications (control logics) are modeled as finite automata. By using TCT procedure, this paper synthesizes the supervisory controller (supervisor) and shown that the specifications are controllable and the closed loop system is nonblocking. Finally, we compare our supervisor with the controller in Xiamen bipole VSC-HVDC project. The comparison results show that the control logics of our supervisor are the same as the control logics of the controller in Xiamen bipole VSC-HVDC project..