HYDRO ELECTRIC POWER STATION IN MALAYALAM

Hydro-electric Power Station Hydro-electric power plant is the power plant utilizing the potential energy of water at a high level for the generation of electrical energy. It cannot be located everywhere. Firstly there must be an ample quantity of water at sufficient head and secondly a suitable site must be available. The amount of power that can be developed depends on the quantity of water available, the rate at which it is available, the head etc. In a hydro-electric power station, water head is created by constructing a dam across a river or lake. The pressure head of water or kinetic energy of water is utilized to drive the water turbines coupled to alternator and, therefore, generation of electrical power. Schematic Arrangement of a Hydro-Electric Plant The schematic arrangement of a typical hydro-electric plant is shown in figure. An artificial storage reservoir is formed by constructing a dam across a river and a pressure runnel is taken off from the reservoir to the valve house at the start of the penstock. The valve house contains main sluice valve for cutting off water flow to the power station and automatic isolating valves for cutting off water supply in case the penstock bursts. A surge tank is also provided just before the valve house for better regulation of water pressure in the system. From the reservoir the water is carried to valve house through pressure tunnel and from valve house to the water turbine through pipes of large diameter made of steel or reinforced concrete, called the penstock. The water turbine converts hydraulic energy into mechanical energy and the alternator coupled to the water turbine converts mechanical energy into electrical energy. Water after doing useful work is discharged to the tailrace. Advantages 1. No fuel is required by such plants as water is the source of energy. Hence operating costs are low. 2. The plant is highly reliable and it is cheapest in operations and maintenance. 3.It is very neat and clean plant because no smoke or ash is produced. 4. Such plant are robust and have got longer life. 5.Highly skilled engineers are required only at the time of construction but later on only a few experienced persons will be required. 6 . Such plants in addition to generation of electric power also serve other purposes such as irrigation and flood control. Disadvantages 1. It requires large area. 2. Its construction cost is very high and takes long time for erection. 3.Long transmission lines are required as the plants are located in hilly areas which are quite away from the load centre. 4. There is uncertainty about the availability of huge amount of water due to dependence of weather conditions.

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