Voltage and Reactive Power Control in Systems With Synchronous Machine-Based Distributed Generation
Artikel i vetenskaplig tidskrift, 2008

This paper investigates voltage and reactive power control in distribution systems and how the presence of synchronous machine-based distributed generation (DG) affects the control. A proper coordination among the onload tap changer (OLTC), substation switched capacitors and feeder-switched capacitors in order to obtain optimum voltage and reactive power control is proposed. It is assumed that there is no communication link between the OLTC and the capacitors, a normal case in distribution system operation these days. The results indicate that the proposed method decreases the number of OLTC operations, losses, and voltage fluctuations in distribution systems, with and without DG present. The power-flow reversal due to the DG is shown not to interfere with the effectiveness of the OLTC operation. Further, it is also shown that as long as the available capacitors are enough to compensate the reactive power demand, the DG operation mode does not give a significant effect to the distribution system losses. However, DG operating at a constant voltage is beneficial for a significant reduction of OLTC operation and voltage fluctuation in the distribution system.

Distributed generation (DG)

Reactive power control

Synchronous machine

Voltage control


Onload tap changer (OLTC)


Ferry Viawan

Chalmers, Energi och miljö, Elkraftteknik

Daniel Karlsson

Chalmers, Energi och miljö, Elkraftteknik

IEEE Transactions on Power Delivery

0885-8977 (ISSN)

Vol. 23 2 1079-1087


Annan elektroteknik och elektronik



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