Event-Triggered Control of Frequency in Interconnected Power Systems

Load variations cause frequency and voltage drifts in a power system. Frequency deviations are reduced to the nominal value by AGC which is a combination of LFC and AVR. LFC employs two types of control. Primary control always operates to ensure reduced frequency deviations whereas Secondary control ensures zero steady state error. Control can be integral, PI, or some other known techniques. The PI controller is tuned using trial-and-error methods which is inappropriate for large variety of operating circumstances. Also, the control greatly depend on the measured values of the quantities as well as their propagation in the communication channels. The open communication network plays a significant role in data transmission, but has the issues like packet drop, finite communication delay, and communication burden. ETC proposed to resolve these issues, the amount of data transmitted is minimum restricting the packet drops. In this work, in order to introduce dynamic tuning of the controller gains, the secondary control of Load frequency is done using fuzzy PI controller, to efficiently reduce drifts. In Proposed fuzzy control, K
p
and K
i
values of PI controller are designed for a range of values, rather than using the same values for all range of errors. Satisfactory operation of the event and fuzzy control scheme is validated for a two area system using extensive simulations. Under the scheme proposed, it is observed that the frequency deviations is reduced effectively with reduction in packet drop and thus better utilization of communication network. Also the proposed method has better time domain performance than the PI controller reported.