CHINA ULTRA-HIGH VOLTAGE GRID

CHINA ULTRA-HIGH VOLTAGE GRID
Liu Yunpeng

Development of UHV Development History of World Transmission Voltage Levels
Over the past hundred years, the development of electric power always focused on the theme of improving transfer capability and reducing transmission cost. New technologies and energy demand with economic growth, is the engine of this process

Development of UHV Development History of World Transmission Voltage Levels
Raising voltage level is the most efficient way to improve transmission power

Development of UHV Study and Development of UHV Transmission in the Word
In 1960’s and 1970’s , in order to meet the growing needs of electric power and in order to carry out long distance and bulk capacity transmission ,USA, USSR, Japan, Italy, Canada and Brazil began to study the UHV transmission technology . In 1970’s ,USSA had an in-depth study on insulation, system, line and apparatus of UHV transmission, substation equipment and their effects on environment. Moreover, USSA carried out test research and equipment manufacturing. Japan began to study UHV transmission technology nationwide in Japan also constructed Akagi Test Center, Shiobara Test Laboratory and Hitachi Test Laboratory successively. Thorough studies of the mechanical and electrical performance and electromagnetic environment of HUV transmission were done.

Lenox High-voltage Test Center, USA USA began to do UHV test research in 1974, several test lines were constructed successively . Research of AC & DC environment tests. AC & DC line tests in the same corridor, magnetic field tests of UHV conductor with special arrangement and mechanical character tests were carried out.

1000kv test facilities in Suvereto, Italy In the middle of 1970’s ,Italy began to study UHV transmission technology. They also constructed several test laboratories and carried out research of electrical and mechanical characteristics of the line , vibration and galloping of conductor ,ice-coating, spacer, etc.

Development of UHV UHV Practice in the Word
1150kv AC transmission line and ±750kv DC line of USSA UHV tower of USSA From the end of 1980’s, 2362km 1150kV AC transmission lines were constructed successively in USSR. Three substations and two segments of lines were put into service accumulatively for more than 5 years. In the end of 1970’s, USSA also practiced±750kV DC project (6000MW and 2414km). The main equipments passed the type test and 1090km transmission lines were constructed. Most earthwork and equipment installation in converter station at the both ends of the line were completed.

Development of UHV UHV Practice in the Word
1000kv transmission line in Japan, operated at 500kV since completed Sin-Haruna UHV equipment test field GIS with double-break GCB(1100kv/8000A/50kA) 3×1000MVA transformers 1000kv transmission project was constructed by TEPCO in TEPCO built Sin- Haruna UHV equipment test field in 1996 and completed the construction of 427km ,1000kV double circuits lines on the same tower in 1999. 1000kV transmission lines in Japan

Development of UHV HVDC Projects in the Word
Development of thyristor valves The HVDC transmission engineering technology has developed from the mercury-arc valve era to the thyristor valve era since it was applied to the electric power system in the 1950’s. The thyristor valve era has also witnessed an improvement from 3’’(inch) thyristor to 5’’ ones. At present , there are more than 80 HVDC projects in service playing a significant role in the long distance, bulk power transmission.

The HVDC project between Kazakhstan and Russia , ±750kv with capacity of 6000MW The Itaipu HVDC project in Brazil, double-circuit transmission lines with each circuit of 800km, ±600kv, 3150MW bipolar line

The Pacific HVDC project in America, ±500kv, 2000MW, each converter for a pole consists of three 133kv, 6-pules mercury- arc valves and one 100kv, 6-pulse thyristor valves which are connected in series.

Development of UHV Study and Development of UHV Transmission in China
Since 1986 , the UHV transmission research was include in the mega-projects of Scientific Research for the 7th Five-Years Plan,8th Five-Years Plan and 10th Five-Years Plan in China . Some subject researches had been developed , including the demonstration on long distance transmission and voltage level ( ) structured by importance Project Ministry of State Council, the prophase demonstration on UHV transmission & feasibility study on 1000kv UHV AC transmission ( ) structured by Ministry of Science and Technology of China, and etc.

China Electric Power Research Institute (CEPRI) , Wuhan High Voltage Research Institute of SGCC (WHVRI) , Beijing Electric Power Construction Research Institute of SGCC (EPCRI) and relevant universities and colleges had researched on the UHV transmission technology since 1968. Flashover characteristic of external insulation , effect on environment, power frequency overvoltage and switching surge had been studied .WHVRI constructed 200m 1000kv test line with 8 bundle conductors in 1994, in 2004 EPCRI constructed a tower test site, where strength test with UHV tower and vibration test with UHV transmission lines can be carried out.

On October 2nd ,2006, the first full-scale HUV tower passed the strength test successfully in China At the end of 2004 , the State Grid Corporation of China started research on key technology of UHV ,including power system analysis of UHV AC &DC transmission , engineering design, construction and test ,and manufacture of main equipment , etc. Plentiful achievements have been achieved.

Development of UHV UHV AC Test & Research
The first 1000kv UHV AC Test Line in China Type test of CVT

Test of live working of UHV AC Ground lightning density along the corridor of 1000kv UHV AC transmission line

Research of the lightning parameters along the corridor of 1000kv UHV AC transmission line Test of 1000kv transformer bushing

Development of UHV 750kv Transmission Pilot Project in China
The 750kv transmission pilot project of SGCC with highest altitude in the world is domestically designed ,constructed, manufactured and commissioned . It is of the world most advanced level and has in-service successively for 1 year. The total length of the 750kv transmission line project is km from Qinhai Province to Lanzhou East in Gansu Province. It has 263 mainly steel towers self-supporting. Six-bundle LGJ-400/50 and Six-bundle LGJK-300/50 steel reinforced aluminum conductors are adopted.

Simplified GIS (made by New Northeast Electric in cooperation with Korean Hyosung) and main transformer of 3×500MVA(made by Xi’ an Xibian Electric) were adopted in 750kv Lanzhou East substation ,which has a single 750kv outgoing line.

Simplified GIS (made by New Northeast Electric in cooperation with Korean Hyosung) and main transformer of 3×500MVA(made by Baoding Tianwei Co.LTD) and Shunt reactor of 3×100Mvar (made by Hengbian of TEBA) were adopted in 750kv Guanting substation , which has a single 750kv outgoing line.

Development of UHV The Development of HVDC in China
In 1987 , the 1st HVDC project in China , Zhoushan ,was put into trial operation. ▲ Rated voltage: 100kv ▲ Rated power: 500MW ▲ Valve: Thyristor valve 2. In 2003 , Three Gorges-Changzhou HVDC project, was put into trial operation. ▲ Rated voltage: ±500kv ▲ Rated power: 3000MW ▲ Valve: 5 inch Thyristor valve 3. The HVDC technology of China is developing with steps. Up to Lingbao BTB project ,it has been configured, designed, manufactured and commissioning independently.

Ge-Nan ±500kv ,1200MW HVDC Transmission Project, in 1990 Three Gorges-Changzhou ±500 , 3000MW HUDC Transmission Project, in 2003

Linbao BTB HVDC Project, 360MW in 2005 Three Gorges-Shanghai ±500 , 3000MW HVDC Transmission Project, in 2006

Development of UHV Research Achievement of UHV
Since 1960’s ,lots of researches have been done at home and abroad ,such as electromagnetic environment & ecological impact, overvoltage & insulation coordination, production & operation of equipment, etc. The UHV project was operated under full voltage once in USSR . The UHV pilot project were built in Japan and Italy . CIGRE working group evaluated the UHV technique and conclusions were drawn that the application of UHV AC transmission technology was fully developed and ±800kv UHV DC was feasible technically.

Linear relationships between pollution withstand voltage and insulator string length Switching impulse flashover voltage of air clearance under UHV Lots of researches have been done on the performance of HV equipments or insulation models with different sizes and dielectric under power frequency, lightning and switching overvoltage conditions. The principles of insulation coordination of UHV transmission system were basically determined.

Lots of researches have been done for audible noise, radio interference, television interference, effect of electric field and magnetic field on human beings under UHV AC transmission line. According to optimum design, the environment impacts of UHV AC transmission line can be reduced to that of EHV AC. At present , the highest level of circuit breaker is 1100kv , 50kA with double-break , the transformer is 1150kv single phase and 667MVA with single unit ,or 100kv single phase and 1000MVA with double units ,the HV shunt reactor is 1150kv , 300Mvar single phase.

Development of UHV Advantages of UHV
Transmission capabilities of AC and DC systems at different voltage levels (MW) ▲To improve transmission capacity Bbmkjjkjk ▲To increase transmittable distance

Bbmkjjkjk AC line losses at distance voltage levels The width of AC line corridors at various voltage levels ▲To save line corridors ▲To reduce line losses

DC transmission capabilities per unit corridor at different voltage levels (MW/m) AC transmission capabilities per unit corridor at different voltage levels (MW/m) Bbmkjjkjk ▲To optimize structure of grids ▲To lower project investment

Necessity of UHV in China Power Demands Increase Rapidly with Fast Economic Growth in China
China generation installed capacity increasing trend According to the developments planning of the 11th-Five-Year Plan, the primary targets of China’ s economic and social development in the period are as follows: macro-economy develops smoothly , the average of GDP grows at 7.5% annually and the per capita GDP will be doubled compared with that of the year 2000. Bbmkjjkjk

In recent years, power demand grows continuously in high speed in China. The whole society power consumption has been annually increasing at more than 10% in a row of the last 4 years . Furthermore , the former three quarters of 2006 has witnessed a rate of 13.7% . According to the development targets known as “ building a well-off society ” , the whole society electric consumption in 2010 is predicted to be 3800TWh and the national installed capacity will fall to 0.75 from 2011 to 2020, 6100TWh of whole society power consumption and GW of national installed capacity can be expected in 2020. Bbmkjjkjk

21% 66% China generation pattern in 2020 In China, the resources of hydro power and coal are available in abundance while oil, natural gas and uranium material are insufficient. The hydro power and coal resources are backbone in generation energy supply in China. The structure dominated by coal and hydro power is difficult to be changed in quite along period. Bbmkjjkjk

The distribution of generation energy resource and power demand in China differs sharply from place to place. More than 80% of the hydro power resources are centralized in west China, 2/3 of the coal resources are centralized in north and west China . It is an unavoidable trend that the inter-area large-scale transmission of energy and power existing with the transmission distance varies from 500km to 2000km. This is the fundamental preconditions of consideration on development direction of China power grid. Bbmkjjkjk

Necessity of UHV in China Abundant Hydro-power Resource in West-South China
The development plan of the hydro-power in the area of the Jinsha River The trunk stream of Jinsha River has total length of 2,290 km , and descent of 3,280m. There are abundant hydro-power resource owing to the ample and stable water flow, and the great and concentrated water descent. The resource are so abundant that the installed gross capacity will be about 75GW, which accounts for 20% of all exploitable hydro-power reservation in China. Yalong River , Daduhe River , Lancang River also have abundant hydro-power resources. 2

Geographical location of the hydro-power in the area of the Jinsha River Twelve hydro-power plants were planned to be built in the trunk stream of the Jinsha River , including the hydro-power plants designed in Yalong River and Daduhe River . The area of the Jinsha River will have 100GW installed gross capacity , which accounts for 25% of all exploitable hydro-power reservation in China. Bbmkjjkjk

The phase Ⅰ project for the lower reaches of the Jinsha River will be of installed capacity of about 18.6GW , even 0.4GW more than the Three Gorges Project, which makes it be entitled as “the second Three Gorges Project” . These hydro-power bases with large installed capacity scale are concentrated and remote from load centers with distance of more than 1000km with limited line corridors . It is UHV DC that is required to transmit hydro-power out. Bbmkjjkjk

Necessity of UHV in China Problems of Power Development in China
The backbones consisting of 500kv AC and ±500kv DC are difficult to meet the requirements resulting from doubling the installed gross capacity and overcoming problems of inverse distribution of energy sources and loads for the following reasons: ▲ Without enough substation sits and line corridors ▲ Short-circuit currents beyond standards at heavy loaded areas ▲ Difficulties in coal transportation Bbmkjjkjk ▲ Weak basis for power grids security ▲ Heavy pressure on environmental protection

Necessity of UHV in China Problems of Power Development in China
The installed gross capacity in China is 510GW and that of small coal-fired power plants accounts for a considerable proportion. The irrational configuration of power sources results in high coal consumption for power generation which is about 50g/kWh more than that of the international advanced level. Developing large hydro power , coal-fired power transmission , optimizing the resource distribution in a large scale , can avoid environment pollution and accelerate the clean and high efficient application of coal resources and sustainable development of power industry in China. Bbmkjjkjk

Necessity of UHV in China Development of UHV is Inevitable for China’ s Progress
The development of UHV will increase the efficiency of exploitation and utilization of energy , which is in line with the overall strategy of constructing the society of resource saving and environmental friendly , and it is also an effective way to ensure security of power grids and improve the integrated social benefits. ▲ To improve security and reliability of power grid ▲ To reduce the corridor numbers and save land resources ▲ To optimize the layout of grid and electric power configuration Bbmkjjkjk ▲ To promote the development of China’ s western region and coordinated development of regional economy ▲ To ease the pressure of coal transportation by railway and decrease environmental pollution of China’s eastern region

UHV Practice in China Prophase Reasoning of UHV Power Transmission Project
Consultation Conclusion on Significant Technical Issues In July 2005, a project consultation group was established in Chinese Academy of Engineering ,consisted of 27 academicians and 7 experts . It has been clearly pointed out in the consultation advice that there are significant engineering application prospects for UHV transmission technology in China. The research and engineering application of UHV transmission should be accelerated . The group suggested that UHV AC pilot project should be implemented according to a comprehensive and rigorous experimental verification program. Bbmkjjkjk

Feasibility Research Conclusion of UHV Transmission Technology Based on abundant researches and investigation of equipment manufacture capacity, feasibilities on both technical and engineering aspects of 1000kv UHV AC transmission and ±800kv(6.4GW) UHV DC transmission have been confirmed. Bbmkjjkjk

Conclusion of UHV Backbone Grid Configuration Planning and Demonstration UHV AC design aims at a higher voltage level grid construction . Its goal is to construct the backbone grid with strong configuration in North China . Central China and East China , cover large coal fired powr , hydro-power , nuclear power resources effectively . UHV DC design aims at the long distance transmission from large power bases in the western area of China based on the strong AC network . The ultimate goals are to construct a strong transmission network with both AC and DC as to improve grid configuration and to enhance system security and reliability. Bbmkjjkjk

UHV Practice in China Jindongnan-Nanyang-Jingmen 1000kV UHV AC Experimental Pilot Project
The 1000kV Jindongnan-Nanyang-Jingmen UHV AC experimental pilot project consists of three substations and two segments of transmission lines. It starts from Jindongnan substation in Changzhi city of Shanxi Province, via Nanyang switching station in Nanyang city of Henan Province, and ends at Jingmen substation in Jingmen city of Hubei Province. The static investment of this project is 5,688 billion yuan (RMB). Jindongnan substation is located at Shanxi Province, covering 8.7ha., with Nanyang switching station at Henan Province, covering 8.86ha., and Jingmen substation at Hubei Province, covering 16.64ha.. The project planning map

UHV Practice in China Jindongnan-Nanyang-Jingmen 1000kV UHV AC Experimental Pilot Project
The total length of recommended lines is about km (including a large span of 3.721km crossing the Yellow River and the other one of 2.956km crossing the Hanjiang River). The length of two Segments of 1000kV transmission line are about 360km and km from Jindongnan to Nanyang and from Nanyang to Jingmen respectively. Single phase transformers of 1000MVA and single-phase HV shunt reactors of 320Mvar are adopted. GIS/HGIS and two-breaker configuration are applied in electrical connection scheme. Rated short-circuit breaking current on 1000kV side is 50kA, and 63kA on 500kV side. External insulation of outdoor equipments in substations (switching station) are designed according to III-class pollution standards.

UHV Practice in China Electromagnetic Environment of UHV AC Transmission Line
Large cross-section, multiple-conductor bundles are used in UHV project, and the distance of conductor to ground is increased to maintain the controlling level of electromagnetic environment identical with that of 750kV, 500kV AC transmission project. Electric field strength on ground is reduced rapidly by increasing the height of conductor to ground

UHV Practice in China Electromagnetic Environment of UHV AC Transmission Line
Electromagnetic environment indices of 1000kV AC transmission project Environmental influence factor Controlled value Remark Electric field strength kV/m 4 Inhabitant houses nearby 7 Cross over highway 10 Other areas Magnetic induction intensity(μT) 100 Radio interference dB(μV/m) 55 0.5MHz, 20m away from the projection of the outer phases in fair days Audible noise dB(A) According to the environmental protection requirements Referring to National Standard <Standard of environmental noise of urban area>(GB )

UHV Practice in China UHV AC Experimental Pilot Project Substation
Jindongnan substation adopts GIS. The rated power of auto-transformer is 3×(1000/1000/334) MVA with one standby phase. The auto-transformer is single-phase, oil immersed. There are five 500kV outgoing lines and one 1000kV outgoing line. The capacity of the shunt reactor is 3×320Mvar with one standby phase. The reactance of the neutral-point reactor is from 245Ω to 280 Ω. At present stage, two groups of low-voltage shunt reactors with capacity of 240Mvar and three groups of low-voltage shunt capacitors with capacity of 240Mvar are installed at the tertiary side of UHV transformer. Jindongnan substation planning graph

Nanyang switching station adopts GIS. There are two 1000kV outgoing lines at present stage. Two groups of 3×320Mvar shunt reactors are installed with one standby phase and two groups of neutral-point reactors. The reactance of one group of the neutral-point reactor is from 327Ω to 370 Ω, and the other one is from 345 Ω to 370 Ω. Nanyang switching station planning graph

HGIS is adopted in Jingmen substation. The rated power of auto-transformer is 3×(1000/1000/334) MVA with one standby phase. The auto-transformer is single-phase, oil immersed,. There are two 500kV outgoing lines and one 1000kV outgoing line. One group of 3×320Mvar shunt reactors are installed with one standby phase and one group of neutral-point reactors. The reactance of the neutral-point reactor is from 414Ω to 440 Ω. At present stage, two groups of low-voltage shunt reactors with capacity of 240Mvar and three groups of low-voltage shunt capacitors with capacity of 240Mvar are installed at the tertiary side of UHV transformer. Jingmen substation planning graph

UHV Practice in China Selection of Bundle Conductor Ground Wire and Tower Design of UHV AC
The altitude of areas where transmission lines of UHV AC experimental pilot project going through does not exceed 1500m, and 78% region is below 500m. The pollution class of most areas is above II. Galloping occurred frequently in Jingmen section. Transmission lines in Taihang Mountains have special weather conditions, such as extremely heavy ice and high speed wind. The project is recommended to use ACSR conductor bundles of 8×500mm2, of which the split spacing of sub-conductor is 400mm, and circum-circle diameter of conductor bundles is 1045mm. The distance of conductor to ground is 22m in non-residential area and 27m in residential area. Ground wire is recommended to be OPGW-175 or JLB20A-170. Cat –type tower is adopted in plain areas and cup-shape tower in mountain areas. V-type insulation string is adopted at the mid phase and I-type in the outer phase. The tension angle support tower adopts the type of “干”. The recurrence of the maximum wind speed is considered to be once in 100 years. The maximum designed wind speed is not lower than 27m/s at 10m above ground.

UHV Practice in China Selection of Bundle Conductor Ground Wire and Tower Design of UHV AC
Sketch of cup type tangent tower Sketch of high-low foot tower 8 bundle conductors Figure of cat-type tower, cup-shape tower and tension tower Sketch of crossing HanJiang river large span

UHV Practice in China Main Design Values of UHV AC Transmission Project
In clean area, 54 pieces of common cap and pin insulators is selected for one insulator string. Anti-fog insulator with sheds is selected in light pollution area, three sheds in middling pollution area and composite insulator is selected in heavy pollution area. UHV AC Phase to Tower Clearances (m) Case Altitude 500 1000 1500 Power frequency voltage Outer phase (I type) 2.7 2.9 3.1 Switching surge Intermediate phase (V type) 6.7 7.2 7.7 5.6 6.0 6.4 Intermediate phase of crossing river span tower (I type) 6.2 6.6 7.0 Live line work Outer phase (I Type) Intermediate phase to tower window (V type)

Minimum Clearances of Substation in Altitude 1000m Area (m) Clearances Type of flashover voltage Design value Phase to ground Positive polarity switching surge flashover voltage 6.8 Phase with 4 sub-conductors in bundle to ground 6.8 Tube bus to ground 7.5 Ring to ground Phase to phase 9.2 Between phase with 4 sub-conductors in the bundle 10.1 Ring to Ring 11.3 Tube bus to tube bus

1.The insulation level of UHV line is very high, the possibility of back flashover caused by lightning stroke to ground wires or tower top will be low. 2.Because the tower of UHV line is high, the shielding failure possibility may be high. The expected lightning outage rate of 1000kV line should be lower than that of 500kV line. 3.This type of UHV tower will have good lightning protection performance. If the formation of conductors is horizontal, intermediate phase insulator string is V string and side phase insulator string is I string. In plain area, the shielding angle should be less than 5 degree, and in mountainous area, the shielding angle should be negative. 4.At the two terminals near the substation, within 2km, negative shielding angle is selected. CVT and shunt reactor will use the same MOA, and on either buses a MOA should be installed.

UHV Practice in China Overvoltage and Insulation Coordination for UHV AC Transmission System
In UHV AC experimental pilot project, the rated voltage is 1000kV, the highest operating voltage is 1100kV, the rated current is 4000A, and the rated short-circuit current is 50kA. High performance MOA is installed on the bus and the line. Insulation Level of 1000kV UHV AC Equipments (kV) Equipment Sort LIWV (Peak) SIWV (Peak) AC (RMS) Transformer & reactor 2250 1800 1100 (5min) Circuit break (CB) & Disconnector 2400 1100 (1min) CVT、TA Clearance between open contacts of CB (1min)

Overvoltage Control Measures of 1000kV UHV AC Experimental Pilot Project: 960/720/720/600Mvar shunt reactors and neutral grounding reactors are installed. It is planed to use the controllable shunt reactor in future development. The maximum secondary current can be limited below 12A by applying neutral reactor and the single phase reclosing intermission time can be controlled within 1 second. Using high performance MOA with rated voltage of 828kV, a configuration of 4 parallel blocks, residual voltage under switching impulse U2kA≤1460kV, and under lightning impulse U20kA≤1620kV. Ωclosing resistor is applied in CB. UHV lines are appropriately divided into several segments.

Overvoltage Level of 1000kV UHV AC Transmission System (p.u.) Type Location Bus side Line side Power frequency temporary overvoltage 1.3 1.4 Statistical switching surge (U2%) Phase to ground 1.6 1.7 Phase to phase 2.8 2.9

UHV Practice in China The Basic Technical Parameters of UHV AC Main Equipment
1000kV Auto-Transformer Technical parameters Guaranteed value Rated power (MVA) HV 1000 MV LV 334 Rated voltage (kV) 1000/ - 110 Cooling method CFAF Insulation Level LI /kV (Peak) Full wave 2250 Chopped wave 2400 TI /kV (Peak) 1400 AC /kV (RMS) 1100(5min) Impedance voltage and Allowable deviation HV-MV(%) 10±7.5% Transformer size L×W×H 12×4.15×4.9 Transportation Weight (t) 375 (metric ton)

1000kV Shunt Reactor 1000kV Shunt Reactor Guaranteed value Rated power /Mvar 200/240/320 Rated voltage /kV 1100/ Connection mode Star connection Reactance /Ω (per phase) 6050/5041.6/3781.3 Volt-Ampere characteristic Keeping linearity in voltage of 1.4p.u. 50% slope after saturation not less than before saturation Insulation Level LI /kV (Peak) 2400 SI /kV (Peak) 1800 AC /kV (RMS) 1100(5min)

1100kV UHV AC Switchgear Technical parameters Guaranteed values Rated voltage /kV 1100 Rated frequency /Hz 50 Rated current /A Main bus-bar 8000 Others 4000 Insulation level LI /kV (Peak) Phase to ground 2400 Interruptures SI /kV (Peak) 1800 AC /kV (RMS) 1100(1min) Rated short duration withstand current and time (kA/s) 50kA/ 2s Rated withstand current (Peak) /kA 135 Rated breaking current Effective value of AC component Time constant /ms 120

1100kV UHV AC Switchgear 1000kV Auto-Transformer 1000kV Shunt Reactor

UHV Practice in China The Output Scale and Scheme of the South-West China Hydro-power UHV DC Project
Phase I of the project at the lower reaches of the Jinsha River is concluded to adopt the scheme of 3 bipolar UHV DV links, each rated on ±800kV and 6.4GW (The actual transmission capability is anticipated to reach 7GW), to deliver power to East China and Central China. The above scheme can save investment of about 7.6 billion yuan RMB than the scheme of 4 links, each rated on ±800kV and 4.8GW and can save about 7.5 billion yuan RMB than the scheme of 5 links, each rated on ±620kV and 3.8GW. Taking the output need of the large hydropower plants (such as the Phase II of the Jinsha River and Jinping plant) into account, the scheme saves valuable corridors area enormously with about 3-4 ones from west to east. Benefits of promoting technical reform and upgrading industries of electric power apparatus and semiconductor will be witnessed. Sketch for the scheme of 3 bipolar UHV DC Links, Phase I, Jinsha River

UHV Practice in China Electromagnetic Environment of UHV DC Transmission
Through applying large cross-section, multiple-conductor bundles and increasing the distance of conductor to ground in ±800kV DC transmission project of China, the level of electromagnetic environment is identical with that of operating ±500kV transmission project. Total electric field strength on ground decreases rapidly by increasing the height of conductor to ground

UHV Practice in China Electromagnetic Environment of UHV DC Transmission
Electromagnetic environment indexes of ±800kV DC transmission project Environmental influence factor Controlled values Note Total electric field strength at ground level (kV/m) 30 Maximum under line 25 Maximum near inhabitant houses 15 80% Maximum near inhabitant houses Ion current density at ground level (nA/m2) 100 DC magnetic induction intensity at ground level (mT) 10 Radio interference (dB(μV/m)) 55 0.5MHz,20m away from the vertical projection of pole conductor bundle Audible noise (dB(A)) According to the environmental protection demand Referring to National Standard <Standard of environmental noise of urban area> (GB )

DC Main Electrical Connection Diagram
UHV Practice in China UHV DC Main Electrical Connection and Converter Station “400kV+400kV” double 12-pulse converters in series Per converter capacity reaches 1.6GW-the highest level in the world 49 ways of operation modes are available, which can be chosen and combined flexibly. The smoothing reactor can be located in the polar line and the neutral line to reduce the inner over-voltage level. Capable of built stage by stage flexibly; High reliability; Single pole outage times:2/year; Dipole outage times:0.05/year; DC Main Electrical Connection Diagram

UHV Practice in China UHV DC Main Electrical Connection and Converter Station
UHV Converter Station airscape (scheme 1/2/3)

UHV Practice in China Thyristor
The research and development of 6-inch thyristors is of technical and economical significance with respect to ±800kV, 6400MW HVDC technology. Compared to 5-inch thyristors, 6-inch ones have an improved short-circuit current capability, which is beneficial to the optimization of HVDC systems. 6-inch thyristors also have larger overload capability, which can increase the transmission capacity. In addition, the wider heat-dissipation area is favored to the design of the cooling system. Using 6-inch thyristors can promote the dynamic performance of HVDC systems as well as the stability, reliability, and security of multiple DC lines operating in parallel. Other advantages include reducing numbers of thyristors, simplifying valve structure, improving aseismatic capability and decreasing valve losses.

UHV Practice in China Thyristor
5-inch & 6-inch thyristors The technical advantages of the 6-inch thyristors: Small thermal resistance Large overload capacity Large current carrying capacity High capacity for surge currents Small recovery charge and low losses

UHV Practice in China Converter Valve
Double valves or quadruple valves can be applied Air insulated, water cooled Each single valve of the 6-inch thyristor valves has 3 layers; each layer has 60 thyristors connected in series, with 3 thyristors in redundancy The valve margins for switching, lightning and steep-front surge wave are 10%,10% and 15% respectively

UHV Practice in China Converter Valve
Quadruple valves Single valve Double valves

UHV Practice in China Line Design of UHV DC Transmission Project
The total length of the three lines of power out project in the Jinsha river first stage is about 5000km, which pass across many heavy ice-coated regions such as Wumeng mountain, Wuling mountain and Xuefeng mountain etc., with complex landform, changing climates, heavy pollution and heavy ice-coating. The highest altitude is 2300m. The air gap of tangent tower with V type insulator string is not less than 6.1m for ±800kV UHV DC transmission line. In the area of 2000m altitude, the altitude correct coefficient of switching impulse flashover voltage for the air gap is The number of anti-fog type insulators for single string in ±800kV DC transmission lines is not less than 65 units (I type string) and 56 units (V type string) for single string in the common pollution area where ESDD is less than 0.05mg/cm2. And composite insulators are recommended in the heavy pollution area where ESDD is higher than 0.1mg/cm2.

Heavy pollution area-Quarry near the line Tower collapse caused by heavy ice-coating Ice-coating of conductor in the ice observation station near the UHV transmission line in Jinsha River area

±500kV tangent tower ± 800kV tangent tower ±500kV angle tower ±800kV angle tower

UHV Practice in China The Demonstration of Common Ground Electrode at UHV DC Output Side
The three UHV DC converter stations at output side of Jinsha River are 20-40km apart from each other. The project of common ground electrode is adopted after study . Its influence on the safety and the reliability of UHV DC transmission system can be reduced by the correct selecting of the electrode site and good design of the ground electrode . The ground electrode lays multi-circles in plane. Bbmkjjkjk

UHV Practice in China The Basic Technical Parameters of UHV DC Main Equipment
Output power (each pole) (MVA) 321.1 Rated voltage (kv) / 170.3 Short-circuit impedance 16%~18% Insulation level Line side withstand level (LI/SI/AC) (kv) 1550/1170/680 valve side withstand level (LI/SI/AC/DC) (kv) 1800/1600/ 920/1270 Polarity reversal test on valve side -980(90min)/ +960(90 min)/ -980kV(45min) Bbmkjjkjk Converter Transformer

Inductance (each pole) (mH) 300 Rated current (kv) 4000 Maximum continuous current (A) 16%~18% Insulation level Terminal to terminal (LI/SI) /kv 2100/1675 Terminal to the ground (LI/SI)/kv 1900/1500 920/1270 Polarity reversal test of Terminal to the ground -980(90min)/ +960(90min/ -980(45min) Bbmkjjkjk Dry-type Smoothing Reactor

Converter Valve Rated current Nominal DC current /A 4000 Minimum continuous DC current /A 330 Maximum continuous DC current at rated power/A 4140 Maximum DC current at rated power of 1.06 times /A 4296 Maximum DC current at rated power of 1.1 times /A 4609 Maximum DC current at rated power of 1.4 times /A 5910 Rated voltage Nominal DC voltage , polo to neutral bus /kv ±800 Maximum continuous voltage/kv 810 Insulation level LIWL/SIWL /kv 1600/ 1800 Bbmkjjkjk

UHV Equipment and Test Smoothing Reactor
±800kv/4000A HV smoothing reactor primary layout Beijing Power Equipment Group (BPEG) Rated DC current : 4296A Rated inductance : 75mH Insulating thermal endurance grade: Turn insulation : H Holistic insulation : F Temperature rise: Average : 70K , Hotspot : 90K Dry-arcing distance on coil surface :4300mm Diameter :5000mm LIWL :1225kv(betwwen terminal); SIWL :1005kv(betwwen terminal)

UHV Equipment and Test NHVS 1000kv GIS
1100kv CB without opening resistor NHVS has signed technical cooperation agreement for UHV switchgears with Japan AE-Power Company . All the drawing for 1100kv circuit breakers will be completed in 2007 and all type tests will be finished in The circuit breaker has double-break chamber. Closing resistor and capacity are paralleled for each break chamber. Each phase has a hydraulic operating mechanism. Prototypes of 1100kv DS and ES are being assembled and tested. All the type tests will be finished before Feb, 2007.

1100kv CB with opening resistor Domestic prototype of 100kv GIS Bus-bar

UHV hollow bushing made by Shenma Company With closing resistor , the switching overvoltage can be limited.

UHV Equipment and Test Pinggao Electric UHV Switchgear
LW kv SF6 circuit -breaker Prototype of 800kv GIS circuit breaker With 1100kv GIS technology introduced from Japan Toshia Company , the domestic renovation production will be realized through cooperation . The type tests and certification will be finished before July,

Prototype of 800kv GIS bus-bar , disconnector and earthing switch

High-power hydraulic operating device (36kJ) GE kv Disconnector

UHV Equipment and Test UHV ES, CVT, Capacity
154kv Full insulation capacitor equipment Wuxi Nissin High-Capacity Power Capacity for UHV With special main insulation configuration technology , kv high-capacity power capacitors are capable to be installed on the ground directly. With low loss, low temperature rise , low PD, high impulse withstand level, the special requirements of UHV can be met.

1000kv CVT developed by Wuxi Nissin 1100kv /63kA ES developed by CG Co tanδ≤0.07%, PD level ≤3pC Excellent anti-corrosion performance Insulation level: LI: 2680kv ,SI: 1860kv , AC: 1230kv

Maximum current non-uniform coefficient in multi columns of disks: 5% Maximum potential distribution non-uniform coefficient :1.17(with grading capacitor configuration) Energy absorption capability : 40MJ 4/10μs withstand current : 4×100kA 1000kv arrester developed by Xi'an XD HV Porcelain Co. Ltd

UHV Equipment and Test UHV Bushing and Insulator
Porcelain Composite Insulation made by Liwang China 1100kv bushing made by MWB Shanghai Rated voltage : 1100kv ; Rated current : 2000A BIL : 2400kv ; SIL: 1950kv Power Frequency Withstand Voltage : 1250kv/5min

Composite Insulator made by Shandong Taiguang Co 1100kv OIP type condenser bushing with porcelain insulation Dielectric Dissipation Factor: tanδ ≤ 0.4% Partial Discharge : ≤10pC , under 1100kv

1100kv post insulator made by Sonca and Xian XD H.V. Porcelain Insulator Co. Ltd BIL : 2550kv ; SIL: 1800kv Power frequency wet withstand voltage : 1100kv Bend failing load : 12.5kN , 16kN

UHV Equipment and Test Fittings for UHV Transmission Line
Rotary clamp spacer double pendulum Vibration damper anti-galloping device

Grading ring bundle damping spacer Fitting for linking tower and insulation string

Yoke plate bundle yoke plate and grading ring for I type suspension insulator string

UHV Equipment and Test The ABB Thyristor and Valves
6-inch thyristor valve module thyristor valve sections under test

the layout of double valves hall the configuration of converter stations with double valves

the layout of quadruple valves hall view of converter stations with quadruple valves

UHV Equipment and Test XJ UHV Converter Valve
components of ±800kv UHV converter valve sections configuration of ±800kv UHV converter valve sections

UHV Equipment and Test Thyristor Made in China
The technical characteristics of 6-inch thyristors developed by Zhuzhou CSR Times Electric Co. Ltd for UHV DC applications : 1. Outstanding dynamic performance 2. Advanced electron irradiation technology 3. Evaporation of thick aluminum layer technology 4. Unique chip packaging technology 5. The design of explosion-proof package

the prototype of 6-inch thyristor (KPE ) have been developed by Zhuzhou CRS Times Electric Co. Ltd

5-inch extra high power electric triggered thyristor 5-inch extra high power light triggered thyristor

Through technology import and domestic innovation, Xi’ an Power &Electronic Technology Research Institute has independently developed the prototype of 6-inch ultra high power electric triggered thyristor for UHV DC applications, which is under perfection through tests and studies. 6-inch ultra high power thyristor developed by Xi’ an Power &Electronic Technology Research Institute

UHV Equipment and Test NARI UHV Control and Protection
Characteristics of UHV AC Protection : 1. Application of hardware and software filter techniques to solve the of high frequency and aperiodic components effectively. 2. Accurate compensation of the capacitive current solves its affection on Differential Protection of Transmission Line. 3. The self-adapted weighted bus-bar protection principle based on the main frequency varieties. 4. The positive sequence voltage is used to calculate the system frequency. 5. Using the delta-star change of the current phase angle for every side of the transformer. 6. The sensitivity of the inter-turn fault of the reactor protection is improved.

UHV Control and Protection made by NARI

DC Protection and Control for UHV : 1. The control function and the protection configuration of each 12 pulses converting unit id independent . Hierarchy configuration scheme for the control system. 2. ±800kv DC current and voltage is also to be maintained . The balanced operation of series valve group can be realized. 3. Realizing the control function and the trigger function. 4. Protection equipment is configuration according to series hierarchy configuration of double 12pulses valve group.

UHV Equipment and Test UHV AC Test Station (SGCC)
UHV AC test station is equipped with UHV AC single circuit and double-circuit lines on the same tower test sections , electromagnetic environment measuring laboratory , climate laboratory , electrical live examination site for UHV AC apparatus and other test equipments. The test station is capable to carry out research on UHV AC electromagnetic environment , insulation characteristics and etc.

Electrical Live Examination Site for UHV AC Electric Appliances Electromagnetic environment laboratory includes 200㎡ (shielded room is 60㎡)measuring & observing laboratory and 120m×50m test field . Research of electromagnetic environmental parameters measurement in all-weather conditions, corona and electromagnetic compatibility research for UHV lines can be carried out.

Climate laboratory for UHV Climate laboratory includes Ф20m*25m climate chamber, 1000㎡ measuring & controlling and auxiliary rooms. The size of chamber is the biggest one in the world . Pollution test , middle and short gap discharge test , flashover test of ice-coating insulator string and etc, can be carried out under simulated climates of altitude up to 5500m.

Test Lines for UHV Test Lines include the tower configuration with single horizontal (or triangle ) and double-circuit vertical configurations. Research on corona characteristics, electromagnetic environmental influence, live working and characteristics of insulators pollution for UHV lines is capable to be carried out.

UHV Equipment and Test UHV DC Test Station (SGCC)
Electromagnetic environment simulation test yard : For research on electromagnetic environment of UHV DC, AC, AC and DC in the same corridor as well High voltage test hall: Lightning impulse voltage test, AC&DC voltage withstand test , partial discharge test, corona and Radio Influence test and relevant research are capable to be carried out. Outdoor test yard : For research on live working , lightning and switching impulse voltage tests.

UHV DC test line For research on electromagnetic environment , corona performance , total electric field , ion current density , RI and AN of UHV DC transmission line. It is the longest double-circuit test line with the highest voltage level in the world.

Corona Cage For research on corona performance of conductor ,double-cage configuration for UHV DC single and bipolar test.

Arrestor laboratory Pollution and environment laboratory insulator laboratory

UHV Equipment and Test UHV Tower and Conductor Test
Tower test station of Beijing Electric Power Construction Research Institute of SGCC: Max. height of test tower : 100m Max. span of test tower foot : 30m Max. uplifting force per tower leg : 10000kN Over-turn torque: >240000kN·m Load measuring and controlling system: 128 channels Test capability : 1000kv single circuit tower, 750kv double circuit tower and 500kv multi-circuit tower.

UHV Equipment and Test UHV Tower and Conductor Test
Beijing Electric Power Construction Research Institute of SGCC has built the vibration lab, stranded wire fatigue lab, conductor wriggling lab, damper lab , spacer fatigue lab , heavy current lab , mechanical property lab and transmission line galloping lab . Electrical & Mechanical performance experiments of conductor and fittings for 1000kv transmission line can be carried out in the institute.

UHV Practice in China XIHARI UHV Lab
Main test equipments of XIHARI 6500MVA short-circuit generator 1000kV/ 7.5MJ oscillating circuit 300MVA short-circuit test transformer

Main test equipments of XIHARI Test bay for UHV equipment 4800kV impulse voltage generator 2250kV power frequency test transformer

XIHARI’S UHV equipment test ability UHV AC high power test Based on the improvement of 800kV high power test circuit, requirements of high power test for 1100kV switchgear will be met by the end of 2006. UHV insulation test A new UHV insulation test hall will be built by the end of 2007 for 1100kV AC and ±800kV DC equipment insulation tests. UHV DC operation test ±800kV /4000A DC operational test ability will be achieved in 2008.

CHINA ULTRA-HIGH VOLTAGE GRID

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