ks3-【v3】operation challenges and solutions of csg 1014(余 … · breaker fault occurred in...

Yu jianguo

2014.10

Operation challenges and solutions of CSG

Index

31 Introduction of CSG

33 Challenges of CSG

2 Main features of CSG

4 Solutions and Techniques

Introduction of CSG Typical AC/DC parallel power grid.

Covers transmission, distribution and supplying in 5 provinces

Supplies about 1 million Square kilometers

Serves 230 million people

YunnanYunnan

GuizhouGuizhou

GuangxiGuangxiHainanHainan

GuangdongGuangdong

Introduction of CSGPower grid structure of CSG by the end of 2002

500kV AC lines

±500kV DC lines

220kV AC lines

HK grid

Power grid structure of CSG by the end of 2012

HK grid

500kV AC lines

±500kV DC lines

220kV AC lines

NuoZhaDu UHVDC

YunGuang UHVDC

XiLuoDu HVDC

Peak load 136 million kW

8 HVDC and 8 HVAC lines in 2014, 70% HVDC

63.5 billion kW West‐East, 60% HVDC, 2014

Utilizing of DC transmission about 3000 hours

AC/DC parallel power grid of CSG in 2014

Introduction of CSG

Index





Main features of CSG

Feature 1：Significant benefits of resource allocation. •80% hydro resources and 96% thermal resources are in the west area. •Over half the loads are located in Guangdong.

Feature 1：Significant benefits of resource allocation. •80% hydro resources and 96% thermal resources are in the west area. •Over half the loads are located in Guangdong.

An increase of nearly 7 times

An increase of nearly 3 times

Peak load occurs in summer in Guangdong

Peak load occurs in winter in the West

Typical monthly Peak load curve Typical daily load curve in summer

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广东广西贵州云南

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广东广西贵州云南

Complementation of load characteristic

Peak load occurs in morning in Guangdong

Peak load occurs in evening in the West


GD GX GZ YN GD GX GZ YN

Feature 2：•Complicated structure•Difficult to operate

•Over 30GW power is transferred from West to East. •AC/DC corridor operates close to limit point of the system in flood seasons

Feature 2：•Complicated structure•Difficult to operate

•Over 30GW power is transferred from West to East. •AC/DC corridor operates close to limit point of the system in flood seasons


North‐West gridInterregional power 2000MW

North‐East gridInterregional power 12000MW

North China gridInterregional power 11020MW

Central China gridInterregional power 8850MW

East China gridInterregional power 12170MW

CSGInterregional power 30000MW

Receiving end of San-Guang HVDC

Receiving end of Yun-Guang UHVDC

Receiving end of XiLuoDu HVDC

Receiving end of Tian-Guang HVDC

Receiving end of Gao-Zhao HVDC

Receiving end of NuoZhaDu UHVDC Receiving end of

Xing-An HVDC

Feature 3: •Many HVDC transmission lines. •Concentrated HVDC receiving ends

In 2015, 8 HVDC transmission lines.Receiving ends all in Guangdong.About 1/3 of the maximum load capacity.

Feature 3: •Many HVDC transmission lines. •Concentrated HVDC receiving ends

In 2015, 8 HVDC transmission lines.Receiving ends all in Guangdong.About 1/3 of the maximum load capacity.


Multi-terminal VSC HVDC Submarine cable

Main features of CSGFeature 4：New technology: UHVDC, Multi-terminal VSC HVDC, High voltage submarine cable, controllable TCSC, STATCTOM, etc.

Feature 4：New technology: UHVDC, Multi-terminal VSC HVDC, High voltage submarine cable, controllable TCSC, STATCTOM, etc.

亚洲首个500kV可控串补

（TCSC ）

3.技术先进TCSC in Pingguo Station STATCOM in Dongguan

Station


Myanmar

Laos

Vietnam

MacaoHK

Feature 5：Connecting HK, Macao, and Southeast Asia. Serves ¼ load of HK, and 90% load of Macao. Some connections with Myanmar, Laos, and Vietnam.

Feature 5：Connecting HK, Macao, and Southeast Asia. Serves ¼ load of HK, and 90% load of Macao. Some connections with Myanmar, Laos, and Vietnam.


Index





Mono-polar blocking of Yun-Guang UHVDC or NuoZhaDu UHVDC

Cause 30-70kV voltage drop at the midpoint of West to East

transmission lines.

Cause 1000MW power oscillation in the 500kV AC transmission line.

Cause power over-limit in relative interfaces.

PMU recording of the voltage drop caused by mono-polar blocking in Yun-Guang UHVDC

Challenges of CSGChallenge 1 ： With AC/DC parallel operation, large power transferring caused by DC faults threatens the stability of system.

Statistic of mono‐polar blocking events in CSG

HVDC bipolar blocking may cause tremendous power transferring to AC sections, hence may cause system instability.

System security depends on proper actions of stability control devices

Challenges of CSG

Statistic of bipolar blocking events in CSG

（2）On Dec. 15, 2012, breaker fault occurred in Yandu station which caused simultaneous commutation failures in 3 HVDC inverters.

（1）On Nov. 7, 2010, An AC grounding fault at a 500kv line in Guangdong caused simultaneous commutation failures in 5 HVDC inverters.

石井

Bei-Hua II phase B fault on 4.27 Hua-Bo II phase

AB fault on 4.12

Luo-Bei II phase A fault on 4.25

Xu-Zeng II phase C fault on 4.27

Yan-Hua II phase A fault on 5.2

An-Guan II phase B fault on 5.3

Bei-Shi I fault on 4.25

Zeng-Sui II phase C fault on 8.11

Sui-Shui II phase C fault on 9.4

Zengcheng #2 transformer Phase C fault on 9.7

Typical faults which caused commutation failures in multi HVDCs of CSG in 2012

Challenges of CSGChallenge 2: Multi-infeeded HVDC in Guangdong – AC faults may cause commutation failures in multi HVDCs or even bipolar blockings.

Long distance, large capacity and long-chain structure transmission lines may cause high risk of low frequency oscillations

Inter-regional low frequency oscillation under a weak system damping

Inner-area low damping oscillations in regional grid may cause the power oscillation in transmission interface

Forced oscillation of generators

Low frequency oscillation of Yunnan-Guangdong in 2003

Forced oscillation of #2 generator, Honghe station in 2008

Challenges of CSGChallenge 3：High risk of low frequency oscillations.

Freezing Rain

Earthquake

Thunder

Forestry fire

Typhoon

Freezing rain occurred frequently and last for long time which impacts wide area.

Approximately 4-5 typhoons attack east coast area every year including Guangdong, Guangxi and Hainan province.

Earthquake happens frequently in Yunnan. Disasters like forestry fire, thunder, mud-rock flow and

landslide often occurs.

Drought

According to statistics，over one-third multi-loop tripping accidents occurred in CSG are caused by bad weather.

Challenges 4：nature disasters occur frequently

Challenges of CSG

• In winter of 2008, southern China encountered a severe freezing rain. • The ice-coating of transmission lines reached 118 millimeter, which

caused over 2000 towers fell down and around 900 towers impaired; • During the hazard, Guizhou grid was seriously damaged and forced to

islanding operation.

息烽

鸭溪

兴仁换流

贵阳

鸭溪

福泉施秉铜仁

青岩

安顺

鸡场

乌当金阳

筑东

南郊

站街

田坝洪家渡

东风

索风营

扎佐

高坡换流

引子渡

两所屯

安顺铝厂

紫云

普定滥坝

双牌铝厂

北郊

水城

野马寨

镇宁

盘县一

盘县二

八河红果

盘南起备

兴义

兴仁

安龙

天生桥二级天生桥一级枢纽站

盘南

湾塘

大田河

盘脚

开阳

乌江厂

南白

新蒲

遵义

海龙

桐梓习水

黔北金沙

毕节

大花水

剑江

都匀

麻江

凯里凯里

恒盛

开怀黎平

镇远青溪

岑巩玉屏

大龙

大龙

川硐

秀山

贵阳

清镇

纳雍二厂

纳雍一厂

安顺

遵义

瓮安

麻尾

至广东白花洞

至广西至广东北郊

至广东肇庆

至车河

至广西河池

至公坪

至湾潭

至重庆黔江至綦江至黄荆堡

220kV交流

500kV交流

500kV直流

图例

黔西大方

龙里

太平

Guizhou grid separated into 7 small grids

Challenges of CSG

Impaired tower

Index





Asynchronous interconnection of Yunnan and

main power grid

Islanding operation of Yunnan DC

sending system

Configuration optimization of

dynamic reactive power compensation

devices

The possible solutions to stability issues

Large-scale security and

stability control system

Coordination between

generating units and grid

Disaster-prevention

system

Solutions and Techniques

4 AC line mode for Yunnan-Guangdong UHVDC islanding operation

（Very low SCR: short-circuit ratio is between 1.22 to 1.52 under full load condition ）

Typical operation modes for YG UHVDC islanding system

Solution 1：Islanding operation at DC sending terminal in Yunnan

5 AC line mode for Yunnan-Guangdong UHVDC islanding operation


During Sep.11th-19th in 2013, CSG accomplished islanding operation of YG UHVDC, which is the first time to take DC islanding as normal operation.

Islanding operation can be used as a normal operation mode of Yunnan-Guangdong UHVDC.

This first UHVDC islanding operation in the world made a contribution to the development of DC transmission technology.


Solution 2：Asynchronous interconnection of Yunnan and main power grid

Implementation schemes of asynchronous interconnection

A back‐to‐back HVDC project , which includes a 1000MW LCC‐HVDC and a 1000MW VSC‐HVDC in parallel, separates three AC connections.

A long distance HVDC project, which has three connection modes at the receiving end, separates two AC connections.

A back‐to‐back HVDC project , which includes a 1000MW LCC‐HVDC and a 1000MW VSC‐HVDC in parallel, separates three AC connections.

A long distance HVDC project, which has three connection modes at the receiving end, separates two AC connections.


CSG built 712 sets of Power security and stability control facilities for 110KV and above system, which makes CSG become the largest and most complicated system in the world.

This system has detected all 166 DC mono‐polar blocking faults and 13 bipolar blocking faults accurately, which protects the system security.

Security and stability control system in CSGSecurity and stability control system in CSG

Solution 3：Large-scale security and stability control system


Four sets of ±200Mvar STATCOMs has been installed in the multi‐infeeded system to improve system voltage dynamic performance, and to improve the recovery characteristics of HVDC systems.

Solution 4: Configuration optimization of dynamic reactive powercompensation devices

These 4 sets of STATCOMs have responded 64 times since installed, thus successfully enhanced voltage stability.


Focus on dynamic stability researches Arrange operation modes reasonably Monitor low frequency oscillation Improve the construction of the grid

Solution 5：coordination between generating units and grid

Make effort on generation PSS configuration Enhance secondary loop and settings management

of regulator, exciter, PSS devices. Perform feed‐in test of regulator, exciter, PSS

devices

Transmission network

Generation


Solution 6：Establish effective disaster-prevention system

Established lightning monitor and location system which covers the

whole CSG area.

Installed On‐line Ice‐coating Monitoring System which covers all lines

in icy areas.

Rectified the technique principle of power grid planning, especially

adapting differential wind‐resistant design for overhead lines near

coastal area.

Established comprehensive emergency communication system for

communication during nature disasters, which consists of fiber optic,

satellite and PLC communication system.


Wind-resistant design of strain tower diagram

Lightning monitor and location system On‐line Ice‐coating Monitoring System

Comprehensive emergency communication system

Solution 6：Establish effective disaster-prevention system


According to “China Southern Power Grid Development and Planning (2013-2020)”published by National Energy Administration, CSG will continue to use HVDC as the main technique to transmit electricity from west to east. Yunnan grid will be a sending network, which is asynchronously connected with the rest CSG system, thus to limit the size of synchronous network. However, there are still lots of research need to be carried out to optimize the size of synchronous system.

Due to the rapid development of new transmission techniques, especially VSC, more attention should be paid on construction schemes for future power grid.

With green energy integrated, including wind and solar power, there will be more pressure on power and frequency regulation, which brings new challenges for system security and stability. Thus it is important to emphasize the balance of system economy and security.

Summary

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ks3-【v3】operation challenges and solutions of csg 1014(余 … · breaker fault occurred in...

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