Neutral current compensation techniques in autonomous wind energy sources

Aarti Gupta,Dinesh Jain,Surender Dahiya

doi:10.1007/s40095-014-0134-0

Abstract

The problem of neutral current compensation has to be addressed in Wind Energy integrated weak micro-grids. This study analyses two types of techniques possible for implementation of neutral current compensation by drawing a comparative research of their application on the same wind energy conversion system. The hybrid micro-grid considered in the study comprises a synchronous diesel generator and an inverter-based wind generator. The results and analysis are conducted by time-domain simulations using MATLAB/Simulink software. The use of electronic power converters that also act as an active neutral current compensator or a zig-zag transformer connected with the load mitigates the problem of neutral current compensation to a large extent. The voltage unbalance factor is also significantly reduced due to neutral current compensation and power quality is enhanced. The results provide the actual operational limits possible under the set of given constraints.

Highlights

The third world countries face severe power crunch due to shortage of generation and some areas are totally devoid ofD
The use of electronic power converters that act as an active neutral current compensator or a zig-zag transformer connected with the load mitigates the problem of neutral current compensation to a large extent
The voltage unbalance factor is significantly reduced due to neutral current compensation and power quality is enhanced

Summary

Introduction

The simulation results validated that the total active power supplied is considerably reduced while achieving active current compensation through inverter This mode of operation is beneficial only when high power quality standard is required. The PWM current controller is used to enable the micro-grid currents (isa, isb, and isc) to track the reference currents enabling it to supply only the fundamental active power, while the wind interfacing inverter fulfills the unbalanced reactive and non-linear current requirements of three-phase four-wire load at PCC. The active power supplied by the WECS is not compromised in case of current compensation by zig-zag control. The reference Vd* and Vq* the outputs of other PI controllers are compared to Vd1 and Vq1 obtained from abc to dq transformation of Vabc (generated voltage). The output is given to the PWM generator which generates controlled pulses SG2 for the IGBT inverter

Findings

Discussion and analysis of results

Conclusion