TABLE OF CONTENTS G. hEidhin
Power electronic devices and systems are becoming an increasingly common feature of power systems. Over the years many power electronic products have been developed and can be used to great effect in the AC transmission and distribution system. Existing examples include:
high voltage direct current (HVDC) power transmission systems
static VAr compensators (SVC) - dynamic shunt reactive power compensation
various forms of motor drive systems based on power electronics, widely used in industry and traction applications
power supplies - many of these are based on power electronic devices.
Future developments may include:
'STATCOM' (GTO based SVC)
static series compensator - dynamic series compensation of transmission lines
unified power flow controller (UPFC) - combined dynamic shunt and series compensators
electronic tap-changer
phase-shifter (also known as a quad booster) - used to share load between parallel circuits. This is generally a mechanical device but could also be implemented as a power electronic system.
The first item, HVDC, is generally the largest of the various power electronic systems and makes the most dramatic difference to power systems. This is described in some detail. The other power system devices (SVC, STATCOM, series compensation, UPFC) are described more briefly.
Early electricity distribution was by DC. Then the transformer was developed so that AC became the universal choice for generation, transmission, distribution and utilisation. However, during the last 40 years many HVDC systems have been built and operated (and a few even decommissioned!). Have...
