A Novel SFL-SM Controller for Statcom to Improve the Dynamic Performance of a Power System with Integrated Wind Generation

Abstract

A novel Single Input Fuzzy Logic (SFL) based Sliding Mode Controller (SMC) is proposed for Static Synchronous Shunt Compensators (STATCOM1) to improve the dynamic performance of a power system having much integration of wind generation using induction generators. The proposed controller consists of an equivalent control term, a switching term and a fuzzy control term. It employs only one input signal, which is the deviation of STATCOM capacitor voltage from its reference value. The major drawback of the basic SMC approach is the undesired ‘chattering’, due to high-frequency; this switching is reduced by introducing a boundary layer in the proposed controller. Using the SFL control term, the improvements of dynamic performance are: maintaining constant voltage at the point of common coupling (PCC) for greater loading, delaying the incidence of Hopf bifurcation (HBF) and saddle node bifurcation (SNB). Hence an increase in load limit is achieved. The effectiveness of the proposed controller is demonstrated through bifurcation analysis of a 10 bus system, in which a Wind Energy Conversion System (WECS) is integrated to the main transmission grid at the eighth bus. Steady state bifurcation diagrams are constructed for the test system and improvement of dynamic response by the proposed controller is illustrated in a bifurcation perspective.