Improving the quality of energy in distributed generation is a rapidly growing, challenging, and interesting area of modern times. In recent decades, a large number of techniques have been developed to improve energy quality. This article attempts to comprehensively examine a wide range of methods for improving power quality in distributed generation. This includes the use of active filters, Dynamic Voltage Restorer, DSTATCOM, reactive power compensation techniques, and an unmodified power quality conditioner. In this test, all of these methods are examined with power quality parameters such as reverse power flow, voltage stability, and current harmonics. This document describes energy quality problems and possible effects on the distribution system due to a grid-connected photovoltaic system.