SVC for Utility

Technical principle

Typical references

Engineering case


SVC is used in HV power transmission network and can improve power transmission and distribution performance of the power system. The SVC installed at one or more positions of the power grid may stabilize the weak system voltage, increase the damping under small interference, raise transient steady-state limit, and improve the transmission capability, with which the power grid may exert its efficiency to the maximum and also reduce the transmission loss. In addition, SVC installed in the distribution network may also improve voltage stability of the distribution network and reduce the voltage fluctuation by a large degree.



Long-distance power transmission SVC is able to improve transmission and distribution performance of the power system remarkably. SVC should be installed at one or several proper points in the grid in order to achieve the following purposes: Stabilize voltage of a weak system Reduce the transmission losses Enhance transmission capacity and make existing grid most efficient Improve transient stability Increase the resistance in the small interference Enhance the voltage control and stability Mitigate the power oscillation SVC strongly safeguards grid-connect operation in China nowadays.

Substation(66/11kV) Rongxin SVC may make quick and precise capacitive and inductive reactive compensation,which will stabilize the bus voltage and increase its power factor and also solve reactive power releasing problem completely.Furthermore,when new SVC is installed,the original fixed capacitor bank may also be fully utilized,and only TCR is required.SVC may reach the optimum effect with minimum investment,and it has becom the most effective method for improving power quality of the regional grid.



The SVC used in the power system, especially the ones in transmission network, is normally in TCR+TSC+FC structure, as described below:


Typical TCR+TSC+FC SVC project of Rongxin


Single-line diagram of TCR+TSC+FC

Typical Performance
	Afghanistan NEPS SEPS SVC Project（Kandahar East）,220/20 kV,-40—+40Mvar,1set，Ongoing
	Afghanistan NEPS SEPS SVC Project（Chemtala）,220/20 kV,170Mvar,1set，Ongoing
	International Nuclear Fusion Research Lab，400/69kV，250Mvar，3set，Ongoing
	Chien Shun Steel SVC，161/22.8kV，115Mvar，1set，2018
	Aceros DM SVC，230/13.8kV，110Mvar，1set，2018
	Rio Bravo Steel，230/34.5kV，36Mvar，1set，2018
	Qingshan Stainless Steel，230/35kV，38Mvar，2set，2017
	Taiyu Steel SVC，220/33kV，90Mvar，1set，2017
	Qingshan Stainless Steel ，230/35kV，155Mvar，2set，2017
	CELEC EP Chorrillos SVC，30/30kV，150Mvar，1set，2017
	STAV Company，220/34.5kV，75Mvar，1set，2016
	Dingxin Sulawesi Nickel Plant，230/35kV，75Mvar，3set，2015
	Fujian Qingtuo Nickel Plant - II，20/35kV，178Mvar，1set，2014
	OM Sarawak Plant，220/35kV，90Mvar，4set，2014
	CSG UHV Yunguang HVDC substation，35kV，120Mvar，2set，2014
	Hami Yandunsan Wind Power，220/35kV，125Mvar，2set，2014
	Fujian Dingxin Nickel Company，220/35kV，160Mvar，1set ，2013
	F&F Steel Plant，220/35kV，75Mvar，1set，2013
	Guagdong Shiji Qingshan ，220/35kV，100Mvar，1set，2013
	Pomina Steel Plant，220/33kV，130Mvar，1set，2012
	National Power Tongyu，500/66kV，90Mvar，2set，2012
	Italy Danieli Group，220/33kV，55Mvar，1set，2012
	Fuco Steel Plant，220/35kV，138Mvar，1set，2012
	Qinhuangdao Xiaoying SVC，220/35kV，45Mvar，2set，2012
	Tosyali Steel，230/34.5kV，140Mvar，1set，2011
	CSG Wuzhou，500/35kV，210Mvar，1set，2011
	Minera Chinalco Peru Toromocho ，220/23kV，68.6Mvar，3set，2011
	CSG Dushan ice melting ，500/35kV，120Mvar，2set，2011
	Chifeng Wengniute wind farm，220/66kV，70Mvar，2set，2011
	SAN-EL Comapny，220/34.5kV，75Mvar，1set，2011
	CSG Guizhou Bijie s/s SVC，220/10kV，45Mvar，1set，2011
	SAN-EL SV，220/20kV，20Mvar，1set，2010
	EVN SVC，220/23kV，108Mvar，1set，2010
	Yongzhounan，500/35kV，180Mvar，1set，2010
	Usha Martin Steel，220/33kV，140Mvar，1set，2009
	Guohua Jinjie SSR mitigation，500/35kV，320Mvar，1set，2009
	Donganshan，220/66kV，140Mvar，1set，2009
	Paisan Steel Plant，20/22kV，40Mvar，1set，2009
	Tosyali Celik Steel，230/34.5kV，36Mvar，1set，2008
	Shanxi Yijing，220/35kV，120Mvar，1set，2008
	Shadeed Steel Plant，220/35kV，180Mvar，1set，2008
	Vanloi Steel Plant，220/22kV，85Mvar，2set，2007
	Sahaviriya Group，220/22kV，34Mvar，1set，2007
	Dong Group，220/11kV，15Mvar，1set，2006
	China, Hainan Yazaitang，220/10kV，70Mvar，1set，2006
	Italy Danieli Group，230/33kV，45Mvar，1set，2006
	Guohua Shenmu，110/35kV，100Mvar，1set，2004
	Haikou Xiuying，110/10kV，6.5Mvar，1set，2002
	Anshan Steel，110/6kV，7.6Mvar，1set，1997

CSG Wuzhou 500kV Substation SVC Project

Customer Needs China Southern Grid (CSG) is the second biggest grid in China operating both high voltage AC and DC transmission lines. The main loads are located at its east part of the grids however the major generators are located at the west. Both 500kV AC corridors and 500kV / 800kV HVDC corridors are used to transmit the needed electric power from west to east. Wuzhou 500kV substation is an important node in the middle of these corridors to receive power flow from both AC and DC transmission lines coming from the west.

Black Lines AC Transmission lines Blue Lines DC Transmission lines Green Circle Wuzhou 500kV Substation
The power needs from the east had been increasing every year, which makes the existing corridors’ transmission capability facing more and more pressure. CSG had to do its best to enhance their power transmission limits. According to a system study a SVC rated 210Mvar at Wuzhou substation will improve the situation. The Guangxi - Guangdong corridor’s transmission limit will increase by 100MW while Yunnan - Guangdong corridor by 30MW and Guizhou - Guangdong corridor also 30MW. So theoretically an extra 160MW power flow will be obtained with SVC in operation. Meanwhile the dynamic voltage stability can also be improved by this SVC when there is any line faults occurred nearby.

RXPE Solution A SVC of 210Mvar was designed and delivered by RXPE for CSG Wuzhou 500kV substation in the year 2008. The SVC includes one TCR branch and two harmonic filter branches as well as two MSC branches, output capacity from -120Mvar inductive to +210Mvar capacitive. The MV busbar was designed as 35kV that is connected to 500kV busbar by a dedicated step down transformer. The thyristor valves were designed as horizontal layout with water/air cooling method. Three circulating pumps had been applied in the cooling system to further improve its overall reliability and availability. Control & protection system were also designed as fully redundant.



Customer Benefits Wuzhou SVC had successfully achieved its design targets. It enabled the CSG dispatching center to increase the transmission power flow of these corridors from west to east. Meanwhile it has also increased the voltage stability of the adjacent network. On June 5th 2009, the substation 500kV bus voltage dropped rapidly due to a line fault. The SVC acted to support the line voltage and helped the grid successfully ride through the incident, which also verified its dynamic performance.