Design and Simulation of a PWM Based Phase Synchronous Inverter for Utility Grid Systems with 20km Feeder Line

In recent years, the utility grid system is more essential for the powertransmission and distribution system because it cannot produce harmfulgases or no discharge waste in the environment. PWM based phasesynchronous invert systems are generally utilised in the high efficiencyenergy supply, long distance and higher power quality. The inverter outputvoltage depends on the coupling transformer, input sources and invertcontrollers. An inverter using a three leg IGBT has been designed for utilitygrid and simulated by using MATLAB2014a. In this paper, both sides ofthe LCL filters are used for removing the DC ripple current, reducing thenoise and synchronous the output phase between inverter and the utilitygrid. The PWM controller has created pulse signal to control the inverter,electronic switches and precisely synchronise with grid line frequency. Inthis system, the input DC voltage 500V, switching frequency 1.65 kHz, grid frequency 50Hz, 20 km feeder (resistance, inductance and capacitance perunit length, which are 0.1153, 1.05e-3 and 11.33e-09 ohms/km) with 30MWthree phase load (active and inductive reactive power which are 30e6 Wand 2e6 var) and also a balanced utility grid load of star configuration (00,1200, and 2400 degree) are considered in the design. On the other hand,three phase transformer consists of three signal phase transformers, normalpower 100e3, magnetization resistance and inductance which are 500 pu and416.67pu are considered in this design. The system conversion efficiencyis 99.94% and 99.96%, while the total THD are 0.06% on inverter sideand 0.04% on grid side.