Stahl lifts sluice gate in high Himalayas

12 March 2018


Stahl has supplied a winch to raise the sluice at a hydroelectric power plant at the foot of the Himalayas.

The power plant, designed to generate 330MW, is supplied by a dam across the Kishanganga river. A 37m-high weir, with a sluice gate weighing 100t, provides a continuous flow of water.

The Kishanganga plant lies at the foot of the Himalayas, more than 2,400m above sea level in the northern Indian state of Jammu and Kashmir. It forms part of a large hydroelectric programme being implemented by the state-owned Indian power utility NHPC Ltd.

The demands on the hoist were high as it had to work reliably in the adverse environmental conditions in the tough mountainous region. The first concepts for the custom solution were developed at Stahl’s headquarters in Künzelsau in south central Germany back in 2009: a stationary SHW 8 winch with a safe working load of 2 x 60,000kg driving two rope drums through a gearbox.

To ensure equal distribution of the weight, the hoist was designed in reeving of 2 x 12/2-1 and the drum was manufactured to a length of L4. The final height of lift achieved was 21.5m at 2 x 150 m rope length. Thanks to a double symmetrical arrangement of the reevings it was possible to realise perfect synchronism of the two load hooks. The total length of the winch system covers almost 9m.

Due to local conditions, the gear motor is mounted vertically. As a result of this unusual assembly, the hoist motor is mounted above one of the two rope drums. 

Robustness of operation was a prime consideration. To ensure safe lowering of the sluice, the engineers designed a seven-fold margin of safety into the ropes. They included a second brake in the winch. The hoist is designed for an ambient temperature between -25°C and +40°C. Robust, pole-changing technology with further tolerance ranges enables safe and continued operation of the motor operation periods of unstable mains power supplies. External ventilation with stopping control in the hoist motor ensures a 15-minute maximum duty for the hoisting technology with a subsequent cooling phase.

The panel boxes and hoist motor of the individual hoists are equipped with heaters to combat the air humidity.

After successful testing in Germany the hoisting system was transported to the installation site more than 5,500km away. The plant is set to go online later this year.