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CHINA ULTRA-HIGH VOLTAGE GRID
Liu Yunpeng
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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
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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
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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
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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
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UHV Practice in China Prophase Reasoning of UHV Power Transmission Project
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
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UHV Practice in China Prophase Reasoning of UHV Power Transmission Project
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
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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
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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.
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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
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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 )
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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
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UHV Practice in China UHV AC Experimental Pilot Project Substation
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
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UHV Practice in China UHV AC Experimental Pilot Project Substation
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
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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)
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UHV Practice in China Main Design Values of UHV AC Transmission Project
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
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UHV Practice in China Main Design Values of UHV AC Transmission Project
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.
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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)
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UHV Practice in China Overvoltage and Insulation Coordination for UHV AC Transmission System
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.
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UHV Practice in China Overvoltage and Insulation Coordination for UHV AC Transmission System
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
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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)
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UHV Practice in China The Basic Technical Parameters of UHV AC Main Equipment
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)
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UHV Practice in China The Basic Technical Parameters of UHV AC Main Equipment
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
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UHV Practice in China The Basic Technical Parameters of UHV AC Main Equipment
1100kV UHV AC Switchgear 1000kV Auto-Transformer 1000kV Shunt Reactor
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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
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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
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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 )
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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
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UHV Practice in China UHV DC Main Electrical Connection and Converter Station
UHV Converter Station airscape (scheme 1/2/3)
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UHV Practice in China Converter Valve
Quadruple valves Single valve Double valves
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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.
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UHV Practice in China Line Design of UHV DC Transmission Project
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
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UHV Practice in China Line Design of UHV DC Transmission Project
±500kV tangent tower ± 800kV tangent tower ±500kV angle tower ±800kV angle tower
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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
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UHV Practice in China The Basic Technical Parameters of UHV DC Main Equipment
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
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UHV Practice in China The Basic Technical Parameters of UHV DC Main Equipment
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
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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)
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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.
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UHV Equipment and Test NHVS 1000kv GIS
1100kv CB with opening resistor Domestic prototype of 100kv GIS Bus-bar
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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,
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UHV Equipment and Test Pinggao Electric UHV Switchgear
Prototype of 800kv GIS bus-bar , disconnector and earthing switch
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UHV Equipment and Test Pinggao Electric UHV Switchgear
High-power hydraulic operating device (36kJ) GE kv Disconnector
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UHV Equipment and Test UHV ES, CVT, Capacity
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
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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
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UHV Equipment and Test UHV Bushing and Insulator
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
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UHV Equipment and Test UHV Bushing and Insulator
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
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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.
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UHV Equipment and Test UHV AC Test Station (SGCC)
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.
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UHV Equipment and Test UHV AC Test Station (SGCC)
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.
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UHV Equipment and Test UHV AC Test Station (SGCC)
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.
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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.
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UHV Equipment and Test UHV DC Test Station (SGCC)
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.
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UHV Equipment and Test UHV DC Test Station (SGCC)
Corona Cage For research on corona performance of conductor ,double-cage configuration for UHV DC single and bipolar test.
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UHV Equipment and Test UHV DC Test Station (SGCC)
Arrestor laboratory Pollution and environment laboratory insulator laboratory
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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.
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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.
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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
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UHV Practice in China XIHARI UHV Lab
Main test equipments of XIHARI Test bay for UHV equipment 4800kV impulse voltage generator 2250kV power frequency test transformer
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UHV Practice in China XIHARI UHV Lab
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.
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