Yangzhuoyong Lake Hydropower Station, the construction facilities of Yangzhuoyong Lake Pumped Storag

The main buildings of the power station: water inlet by Yangzhuoyong Lake, diversion tunnel, pressure regulating well, pressure pipeline, surface workshop and 110kV switch station, water intake by the Brahmaputra River, low head pump, sedimentation tank and pumping steel pipe connected to multi-stage storage pump. The water inlet is located on the edge of the lake, with a bottom elevation of 4426m, and is equipped with a trash trap and a working gate.

The gate size is 2 5m 2 5m, and the maximum quoted flow rate is 16 cubic meters per second. The total length of the diversion tunnel is 5888m, the diameter is 2 5m, and the internal water pressure is 0 21 0 72MPa. The pressure regulating well is differential, with a diameter of 11m and a height of 18m in the upper chamber, and a riser diameter of 2 5m and a height of 54 1m.

The pressure pipeline is a main water supply mode, with a length of 3057m, of which the front section is a buried steel pipe, with a length of 740m and a diameter of 2 4 2 5m; The rear section is a ground steel pipe, with a length of 2317m and a diameter of 2 1 2 3m. The maximum internal water pressure of the steel pipe is 9 76MPa, and the minimum internal water pressure is 5 38MPa.

The ground plant is located on the right bank of the Brahmaputra River, a terrace, equipped with 4 sets of 2 250,000 kW vertical shaft three-machine pumped storage units and one set of 2 250,000 kW conventional unit nest, ** capacity of 11 250,000 kW, total pumping flow of 8 cubic meters per second, plant length 87 65m, width 14 9m, height 38m. The primary auxiliary plant is arranged in parallel on the downstream side of the main plant, with a length of 19 8m, a width of 10 7m, and a height of 10 6m. The secondary auxiliary plant and the main plant are arranged in an inverted "L" shape, with a length of 26 5m, a width of 15 5m, a height of 19 The switch station is 79m long and 79m wide.

The low-head pump room is located on the riverside, with 5 pumps, 4 working and 1 standby; The pumping flow rate of each unit is 2 cubic meters per second, the maximum pumping head is 13 5m, and the pump room is 36 8m long, 11m wide and 22m high. The working section of the sedimentation tank is 80m long, 24m wide and 8m high. The pool is divided into 3 compartments from the low partition wall, and the regular hydraulic sand flushing method is adopted, and the settlement guarantee rate of interception particle size 0 1mm is greater than 80% after testing.

After the river water is precipitated by the sedimentation tank, it enters the main engine.

The inlet steel pipe in front of the energy storage pump is equipped with a pressure regulating well for the pumping system at its end. The pressure regulating well is an overflow type at the top of the cylinder, with a diameter of 2m and a height of 11 75m.

When the hub generates electricity, it takes water directly from Yanghu Lake, passes through tunnels, pressure regulating wells, and pressure steel pipes to the plant, and the tail water is discharged into the Brahmaputra River; During the pumping operation, the water is pumped into the sedimentation tank from the riverside low-head pumping room, and then enters the multi-stage storage pump of the main plant, and flows into Yanghu Lake through the water diversion system.

Sheep Lake is a natural plateau closed lake, with a basin area of 6,100 square kilometers, a water surface area of 620 square kilometers, a water depth of 30 meters, a maximum depth of 60 meters, and a volume of 15 billion cubic meters. After investigation, in the past 100 years, the water level of the lake has changed to about 4440m, and the interannual variation of the lake water level is 4 28m, and the annual change is only in a relatively stable state. The water volume of Yanghu Lake comes from precipitation and glaciers in the basin, and the average annual runoff into the lake is 95.4 billion cubic meters.

Incoming water is mainly consumed by evaporation and tends to be balanced. The Yarlung Zangbo River has abundant water, the driest flow rate in the power station site area is 100 cubic meters per second, the perennial flood reaches 3500 cubic meters per second, the river water surface amplitude is only 3 7m, and the river water level is often maintained at about 3597m, the geological conditions of the power station hub area are relatively complex, located in the composite area of the Qinghai, Tibet, Yunnan, Burma, India and Nepal "bad" shaped structure head and the Himalayan Jianminya arc structure, and the Yarlung Zangbo River fault zone is about 4km away from the power station. **Basic intensity is 8 degrees.

The strata are dominated by folds, and a total of 7 faults pass through the building area, but there is no seepage path of lake water to the adjacent valleys. The rock strata of the diversion tunnel and pressure pipeline are sandslate interbeds and some diabase gabbro stones, and the rock strata are nearly orthogonal to the diversion route, the rock layer folds violently, and the rock mass is relatively broken. The plant is located in the first-class terrace of the Brahmaputra River, the upper part of which is the alluvial gravel layer and the alluvial sand pebble layer, and the lower part is the sandslate interbedded, and the plant is located on the sandslate.

The main engineering volume of the power station: 600,000 cubic meters of earth and stone open excavation, 100,000 cubic meters of hole excavation, 140,000 cubic meters of concrete, 800t of steel plate, and 9,000t of steel bars.

Construction period: 1 year and 3 months for construction preparation, 3 years and 9 months for the main project, and a total construction period of 5 years. The investment in the project is about 7.5 billion yuan based on the 1990 ** water letter absolute level (the estimated budget has not yet been approved).

In 1989, the power station was included in the preliminary project by the State Planning Commission, and in 1990, the State Planning Commission officially included it in the annual plan for infrastructure construction, and the main project started on May 25, 1991. The Chengdu Survey and Design Institute is responsible for the survey and design of the project, and the Armed Police Hydropower Force is responsible for the construction and construction of the project.