Distributed supervisory control solution for under-load tap-changing transformers

Supervisory control theories of Discrete-Event Systems (DES) and Timed Discrete-Event Systems (TDES) are introduced to solve different control problems in power systems, e.g. the voltage control problem of under-load tap-changing transformers(ULTC), which are widely used in transmission systems to take care of instantaneous variations in the load conditions in substations. This paper employs the recently developed supervisor localization technique of TDES to solve the voltage control problem in a distributed fashion. Compared with the previous (monolithic) supervisory control approach, the newly designed distributed supervisory controllers have simpler and more transparent structures, but importantly achieve the same optimal and nonblocking behavior.