A NOVEL CLARKE WAVELET TRANSFORM METHOD TO CLASSIFY POWER SYSTEM DISTURBANCES

With wide spread use of sensitive nonlinear electronic devices the switching transients are capable of degrading the quality of power. Utilities often switch the shunt capacitor banks to cope up with sagging voltage levels, thereby generating transients, which travel into the network of end users. Capacitor switching can cause over voltage, resonance and in advert tripping of Adjustable Speed Drives (ASD) and many other sensitive electronics devices. This paper presents a method to distinguish between transients arising out of capacitor switching, , load switching and line to ground fault. The three phase voltages are first transformed to alpha, beta, and zero sequence components using Clarke transform. The DWT of the alpha, beta, and zero sequence components is obtained and the magnitude of the detail coefficients is used to extract distinguishing features. A real power system has been simulated in PSCAD/EMTDC with lines modelled using frequency dependant phase model.