Editing Static VAR compensator (section)

{{Short description|Alternatively Static VAr Generator}}
In [[electrical engineering]], a '''static VAR compensator''' ('''SVC''') is a set of electrical devices for providing fast-acting [[reactive power]] on [[high-voltage]] [[electric power transmission|electricity transmission]] networks.<ref name="PPDI">{{cite book|last=De Kock|first=Jan|author2=Strauss, Cobus |title=Practical Power Distribution for Industry|publisher=[[Elsevier]]|year=2004|pages=74&ndash;75|isbn=978-0-7506-6396-0|url=https://books.google.com/books?id=N8bJpt1wSd4C&pg=PA74}}</ref><ref name="Deb">{{cite book|last=Deb|first=Anjan K.|title=Power Line Ampacity System|publisher=[[CRC Press]]|pages=169&ndash;171|isbn=978-0-8493-1306-6|url=https://books.google.com/books?id=ebZHT8gzpksC&pg=PA169|date=2000-06-29}}</ref> SVCs are part of the [[flexible AC transmission system]] (FACTS)<ref>Song, Y. H., Johns, A. T.  
Flexible AC transmission systems. IEE. {{ISBN|0-85296-771-3}}.</ref><ref>Hingorani, N.G. & Gyugyi, L. Understanding FACTS - Concepts and Technology of Flexible AC Transmission Systems. IEEE. {{ISBN|0-7803-3455-8}}.</ref> device family, regulating voltage, power factor, harmonics and stabilizing the system. A static VAR compensator has no significant moving parts (other than internal switchgear). Prior to the invention of the SVC, power factor compensation was the preserve of large rotating machines such as [[synchronous condenser]]s or switched capacitor banks.<ref name="Ryan">{{cite book|last=Ryan|first=H.M.|title=High Voltage Engineering and Testing|publisher=IEE|year=2001|pages=160&ndash;161|isbn=978-0-85296-775-1|url=https://books.google.com/books?id=Jg1xA65n56oC&pg=PA160}}</ref>

The SVC is an automated impedance matching device, designed to bring the system closer to unity [[power factor]]. SVCs are used in two main situations:
* Connected to the power system, to regulate the transmission voltage ("transmission SVC")
* Connected near large industrial loads, to improve power quality ("industrial SVC")

In transmission applications, the SVC is used to regulate the grid voltage.  If the power system's reactive load is [[capacitive]] (leading), the SVC will use [[thyristor controlled reactor]]s to consume [[Volt-ampere reactive|VARs]] from the system, lowering the system voltage. Under [[inductance|inductive]] (lagging) conditions, the capacitor banks are automatically switched in, thus providing a higher system voltage. By connecting the thyristor-controlled reactor, which is continuously variable, along with a capacitor bank step, the net result is continuously variable leading or lagging power.

In industrial applications, SVCs are typically placed near high and rapidly varying loads, such as [[arc furnace]]s, where they can smooth [[power quality|flicker voltage]].<ref name="PPDI" /><ref>{{cite book|last=Arrillaga|first=J.|author2=Watson, N. R. |title=Power System Harmonics|publisher=Wiley|pages=126|isbn=978-0-470-85129-6|url=https://books.google.com/books?id=1h9aqRj4o8EC&pg=PA126|date=2003-11-21}}</ref>