The deployment of power electronic devices has become a big concern for power quality in these days. The voltage stabilization of power distribution networks interconnected with Photo Voltaic (PV) is very critical in promoting the smooth operation of all linked devices in the distribution system. Voltage profile maintenance is one of the challenges in PV integration into the grid. Conventional devices such as passive filters, series and shunt filters, synchronous condensers, etc. are insufficient to alleviate numerous problems of power quality. The series compensator is used for voltage quality and the shunt compensator is used for current quality. Also, if these two problems of power quality are simultaneously mitigated, the device is used in the distribution system known as Unified Active Power Filter (UAPF). The shunt and series compensator of UAPF is equipped with a Z-source inverter(ZSI). This paper addresses voltage and current associated existing power quality concerns which including voltage sag, voltage swell, voltage and current distortion and simulates the UAPF device to alleviate these problems. The Unit Vector Template Generation (UVTG) with Improved Second Order Generalized Integrator (ISOGI) based Phase Locked Loop (PLL) is utilized for UAPF controller simulation and experimental results validated the proposed work.