Relative performance evaluation of Novel controllers used for reducing frequency drifts in Power Systems

Drifts in frequency and voltage in a power system are caused by load variations. Automatic Generation Control (AGC), a combination of Load Frequency Control (LFC) and Automatic Voltage Regulator (AVR) reduces frequency deviations to the nominal value. LFC utilizes different types of control, the primary control always operating to ensure decreased deviation in frequency and the secondary control operating to ensure zero steady-state error. Conventionally, the PI controller was used as the secondary control in LFC. It employs a trial-and-error approach to statically fix the controller parameters so that it can operate effectively in a limited range of highly dynamic power systems. To effectively reduce drifts, the PI controller is replaced by a fuzzy PI controller to enable dynamic tuning of the controller gains. In fuzzy PI control, PI controllers are designed to use the same values for all errors rather than a range of values for all error ranges. In practice, both the PI and fuzzy PI controllers takes larger time to settle. This paper introduces model predictive control for maintaining system frequency over a wide operating range. Extensive simulations are used to validate the Model Predictive Control (MPC) control scheme’s satisfactory operation for a single area system. It is analyzed that the frequency deviations are effectively reduced under the proposed scheme. Furthermore, the proposed method effectively demonstrates an improvement in time domain performance when different controllers are used.