Distributed Generation with Voltage Control Capability in the Low Voltage Network

Abstract

Small-scale distributed generators connected to

the low voltage network are generally operated with unity

power factor. However, controlling their reactive power

injection would have an impact on the voltage at their

connection point, if the network is sufficiently weak and

inductive. The purpose of this paper is to investigate how a

small-scale distributed generator connected to a low voltage

network through a power electronic converter can be controlled

to improve the voltage quality at its connection point.

The possibility to control the voltage at a point in the low

voltage network by reactive power injection is limited by two

factors, the small rating of the distributed generator compared

to the short-circuit power at its connection point and the

resistive nature of the low voltage cables. Here, a scheme for

inductively decoupling the distributed generator connection

point from the network is proposed and evaluated. For this

purpose, an inductance is placed between the network and the

generator, allowing voltage regulation by reactive power

injection.

Simulation results and lab measurements show that the

proposed scheme improves the voltage quality at the

microturbine connection point.