| Yantan hydropower station is located on the middle reaches of the
Hongshui river, in Dahua county. It is the fifth stage in the Hongshui river cascade
development. It is 83 km away from the county and 234 km from Nanning, the capital city of
Guangxi. Its geographic coordinate is at 107.50E and 24.10N.
The catchment area at the dam site is 106580km2.The annual mean rainfall is 1508mm,annual mean temperature 20.4℃,and annual mean discharge at the dam site 1770m3/s.The project is of grade one.The main structures are also of grade one.The 1000-year design flood discharge is 30500m3/s,the 5000-year check flood discharge 34800m3/s,The annual mean sediment transport 5080×104 tand the annual mean sediment content 0.98kg/m3.
The reservoir normal water level is 223m, the corresponding reservoir capacity is 26.1×106m3.The limiting water level during flood season is 219 m. When individual operation during early stage, the dead reservoir water level is 204m, the regulating reservoir capacity 15.72×108 m3, the firm output 242MW, the installed capacity 1210MW, and the annual mean energy production 56.6×108kwh,with the utilization hour for the installed capacity 4678h, Besides power generation, in Yantan Hydropower Station, with the impounding reservoir capacity, the 153km of canalized waterway, 107.5km2 of reservoir water surface area and the beautiful landscape in the reservoir area, its irrigation, navigation, fishery and tourism potentials can be fully developed.
| Upon joint operation when upstream cascade project completed, the
dead water level can be increased to 219m, firm output 622MW, annual energy production
82.68×108kwh and annual utilizing hour 6833h.When construction of the upstream
cascade station completed, Yantan Station will be able to fully expand its good effect in
frequency and peak regulation, and solve the energy loss problem caused by waste water due
to maintenance, overhaul or major overhaul. After completion of the upstream cascade
station, phase 2 project will be constructed and the capacity will be increased by 450MW.
The project is composed of the main dam , the power house, the switch station and the ship lift. The main dam is of a concrete gravity type, consisting of the right bank dam section, power house dam section, spillway dam section, ship lift dam section and left bank dam section. It is divided into 28 blocks .The total dam crest length is 525m and the maximum dam height 110m.The flood discharge structure is located in the middle of
the river bed.There are 7 surface overflow bays,1 flooddischarge bottom outlet and 2 sluicing bottom outlet. The maximum discharge capacity is 33400m3/s. The spillway weir surface has WES standard profile,15m width for each bay, weir crest elevation 202m.The flaring gate pier equipbed with bucket for energy dissipation is used. By each bay, one radial sarvice gate is provided; by upstream side of the gate, there is a service gate slot, with 7 bays sharing one service gate.
|The water intake system consists of the intake, the gradual section and the penstock. Each unit has one penstock. The total length of the intake system is 93.88m.The penstocks are inclined buried in dam body. The penstock has a diameter of 10.8m, with a maximum intaking flow 567 m3/s.Trash rack, a service gate and a quick lowering emergency gate are set on the intake. The service gate is hoisted by 2×2500kN gantry cranes arranged on the dam crest. The quick lowering emergency gate is operated by a 800kN/6000kN hydraulic cylinder press.|
The power house is arranged behind the dam on the right bank, it consists of the main power house, erection bay, upstream auxiliary power house, downstream auxiliary power house and entrance building. The length of the power house along the unit center line is 200m,width 60m and height 72.58m.There are four Francis turbine generator units. The generator is of Model SF302.5-80/17000 of a vertical shaft, semi-umbrella type, with rated power 302.5MW; The turbine is of Model HLA286-LJ-800,Max head 85m,Min head 37m,rated head 59.4m,and rated flow 580m3/s, rated power 307.1MW.In the power house, there are 2 sets of 2×300t overhead bridge cranes. Four main transformers are arranged on the platform of elevation 174m,between the dam and the power house.
The 500kV switch station is located on the dam slope by the right bank between the dam and the power house, for which,the construction area is 2530.5m2/s.The switch station is of in-door type, in two levels.The fully-enclosed GIS is set on the elevation of
|181m,out-getting line bushings and surge arresters are arranged on elevation of 194m.2 circuits of 500KV out-going lines go through the power house to lead to the downstream transmission lines.|
The vertical ship lift is of 250t class (the upper navigation waterway, middle navigating channel in 500t class), set by left bank spillway dam section. The full length of navigation centerline is 905m.
2. Construction of the Project and the Engineering characteristics
| Yantan Hydropower Station was included in the state key project
list in 1984.On march 1985,construction of the main structures was started. The river
closure was done on November,1987. On March 1992, the gates were closed to start reservoir
impounding and on September in that year, first unit was put into commissioning.By Jane
1995, all four units were completed and put into commissioning. The project was completed.
The owner of Yantan Hydropower Station is GuangXi ElectricpowerBureau. The designer is GuangXi Electricpower Investigation and Design Institute. GuangXI Yantan Hydropower Project Construction Corporation was responsible
|for the project’s construction as well as its management. The project owner responsibility system was adopted for the construction of the project. Bidding system was carried out for contract award and engineer supervision system was used to control the construction duration, the quality and the investment.|
Rely on scientific advancement, by using new technologies and new processes and means, the design was optimized and the site management was strengthened, which brought about project efficiency and abundant achievements.
--during river closure ,the gap with a maximum flow rate of 6.6m/s, flow 1900m3/s,was closed in only 9hours.the river closure was done one year ahead of schedule. In 1992,the first unit was put into commissioning, which was 9 months ahead of the reasonable schedule approved by the State Planing Committee.
--a serious of new techniques and processes have been sprung up ,they are :RCC construction technique, construction technique of large diameter penstock, press-stress anchorage cable technique, energy dissipation technique by using flaring gate pier combined with bucket, as well as technique of dismantling RCC coffer dam ,among which ,88 items were won national and provincial scientific advance awards.
--with effective management and new techniques ,the project has made a better achievement with less investment. The project’s construction cost per KW is 3389.68yuan.
3. The projects Beneficial Results and it’s Operation Management.
The installed capacity of Yantan Hydropower Station accounts for 14.6% of the total installed capacity for the GuangXi Electric power grid, with annual power generation accounting for 32.43% of that of the grid.Yantan Hydropower Station is the first frequency/peak regulating power station in the grid.
Since the station starts its energy production. the station instantly organized a young,shrewed and capable and high quality staff and workers ,among which, young staff below an age of 35 account for 72%,and staff with various profession title and technical specialists account for 57%. Since establishing the station, it has been operating smoothly,safely and efficiently.In1996,it was attested by the state as a super large enterprise and in 1997,for the month of June and July ,it was awarded by the State Electric Power Corporation as the civilized and standardize enterprise for safe and efficient operation and production ,which form a solid base for the station to become a first class enterprise.
From September 1992 when the first unit starting commissioning till the end of 1999,Yantan Hydropower Station has been generating a 315×108kwh, creating a 2463.24×108 yuan of social output value ,which makes an important contribution to the GuangXI industrial and agricultural production and national economic development.
Main Characteristics of Yantan Hydropower Station
|Location|| Da Hua
|Overflow type×number|| Surface bay×7 bottom
|River||Hongshui River||Weir crest elevation||202m/176m|
|Catchment area||106580km2||Spillway length||159.35m|
|Annul mean rainfall||1508mm||Unit discharge||300m3/m.s
|Annual mean flow||1770m3/s||Encrgy dissipation||Flaring gate+bucket basin|
|Annual mean run off||559m3/s||
|Check flood||p=0.02%,3480m3/s||Hoist type,capacity||Fixed hoist2×2800KN/2×1600KN|
|Power house type||Behind-the-dam power house|
|Regulation||incomplete annual regulation||Dimension of the main power house||L200、W60、
|Check flood level|| (0.02%)
|Penstock layout||Shallow buried inside the dam body|
|Design flood level||(0.1%)227.37m rechecked||Dimension of penstock section||Φ10.8|
|Normal water level||223.0m||Dimension of||WxH8.2x14.1m|
|Dead water level||204.0m||Dimension of tailrace gate||WxH7.5x10.48(m)|
|Total reservoir capacity||34.3亿m3||Intake hoist||8000/6000KN Hydraulic cylinder press|
|Reservoir capacity of normal impounding||26.12亿m3||Tailrace gate hoist||1x1250KN Hoist|
|Regulating reservoir capacity||15.72亿m3||
|Dead reservoir capacity||10.4亿m3||unitsxrated power||4台x307100KW|
|Waater utilization coefficient||71.2%||Runner diameter||8m|
|Type of dam||Concrete gravity dam||Rated r.p.m||75r/min|
|Dam crest elevation||233m||Rated heat||59.4m|
|Max. Dam height||110m||Rated discharge||580m3/s|
|Dam length||525m||Working head||Max. 68.5m|
|Dam width||23.5m||Min. 37m|
|Spillway dam22.5m||Turbine installed elevation||154.5m|
Major losses by inundation
|Inundating farmlandI||(p=505) 59498亩|
|Rated votage/power coefficient||15.75KV/0.875||32533亩|
|Model||SFP7-360000/500||population of resettlement||43176 人|
|Sets/Rated capacity||4台/360MVA||Project permanent occupied land||2547亩|
|Rated voltage||525x2x2.5%/15.75KV||Material consumption||Steel reinforcement||11.29万吨|
|Switch station||Switches||closure indoor SF6 switch gears||4.31万吨|
|Outgoing circuit||500KV3 circuits||Wood||3.71万m3|
|Navigation facility||Model||Vertical ship lift||Construction progress||Generation date||1985年3月|
|Max. Design navigable vessel||Barge 250t||River closure date||1987年11月|
|Navigable water level||upstream 223/212(m)||
Generation date unit 1
|Max ./Min||downstream 162.6/154.5(m)||1993年8月|
|Design yearly cargo shipping||180x104t||1994年6月|
Distance ship reception chamber travel
|60.4m||Main structure completion date||1995年6月|
|Proiect efficiency||Installed capacity||1210MW||
|Guangxi Electric Power Bureau|
|Annual mean generation||56.6亿kwh||
|Guangxi Electric Power Investigating Aan Design Institute|
|Annual utilization hour||4678h||
|Guangxi Yantan Hydropower Project Construction Corporation|
|Guangxi Water Conservency/Eletric Power Construction Supervision corporation|
|Construction features of main structures||Open cut earth work||98.13万m3|
|Open cut rock work||427.59 万m3||
Main construction units
|Guangxi Hydropower Constructin Bureau|
|Earth/Rock filling||76.49万m3||Ge Zhouba Hydropower Construction Bureau|
|Concrete||283.94万m3||Ge Zhouba Hydropower Construction Bureau|
|Harbin Eourth Bureau of China Water Conservency/Hydropower Construction|
|Xian Transformer Factory|