Design of Power System Stabilizer as Second-Order Sliding Mode Controller

This paper aims to present the design of power system stabilizer (PSS) as a second-order sliding mode controller (SOSMC). Power systems have always been growing into more dynamic and complex systems. This is because of continuously occurring disturbances and parametric uncertainties in power systems due to changing loads. One of the major problems with this area is small frequency oscillations which lead to the system instability if these oscillations are not damped properly and also reduce power transfer capability. Therefore, it is essential to use power system stabilizers (PSS) to damp out small frequency oscillations. In this paper, single machine infinite bus (SMIB) system is used as study system. Sliding mode control (SMC) is a nonlinear and very robust control technique. Advantages of this controller can be used to control the power systems in order to increase the stability. But SMC has a major disadvantage of chattering. SOSMC overcomes the disadvantages produced by SMC. Therefore, in this paper, PSS is designed as SOSMC using twisting algorithm and applied to SMIB. The robustness of PSS as SOSMC is demonstrated by carrying out comparative simulation under different operating conditions of the SMIB power system.