KOYNA HYDRO-ELECTRIC – A MARVEL OF ENGINEERING
Let the clichés of wonderment be summoned to describe it. A look-ever would be simply breathtaking. However it may be called, it is undoubtedly an amazing engineering feat – it is the Koyna Hydro-Electric Power Project, called the K.H.E.P. Carved in the majestic Sahyadri Hills of Western Maharashtra, the K.H.E.P. puts to full use the gift of nature – high hills resulting in considerable water-head and the steep tapers of the range towards the Arabian Sea – resulting in generation of hydro-electricity that forms the life of the Western grid. Its output has made Maharashtra self -sufficient; providing power to run industrialised demands and agricultural systems across vast stretches of the state.
A drive across the Koyna region, a scenic marvel, reveals a beautiful liaison between modern technology and nature. Caverns and tunnels, dug deep into the rugged hills, form the framework of this project – all replete with the most modern gadgets and protection systems. The project comprises of four stages – spread out in a region encompassing land in the Satara and Ratnagiri districts.
KOYNA 1ST & 2ND STAGES:
The first stage was developed at Pophali near Koyananagar. Work had commenced on the 16th of January 1954. Two years later began the staggering work of excavation of approach and ventilation tunnels. Stage 1 of the project has four generators of 70 MW and the 2nd stage of the project has four generators of 80 MW, both of which have been recently uprated.
The first two stages involved several developmental levels – including the construction of a concrete dam at Koyna, excavation of head-race and tail-race tunnels, filling of the Shivaji Sagar Lake, among other things. Construction is deep underground – an elucidation of the great civil engineering prowess that has gone into this massive undertaking. Penstocks, fortified with concrete and steel, run through the mountains to give the source for generation. There are four sets of transformers (each set having 3 transformers) each for the 1st and 2nd stages having capacity of 25 MVA for the 1st stage and 30MVA for 2nd stage with a step-up capacity of 11/138.6 KV. A spare is provided for each stage. Cranes are situated underground, while machine halls, EVT, valve house, workshop and GIS (Gas Insulated Switchgear) are arranged intricately in the huge underground complex. The whole construction, well-ventilated and air-conditioned, is divided into three floors. Each floor has different equipment. On the lower-most floor are located the AEG-Germany-manufactured generators. All the maintenance and protection gadgets for the alternators are also present. Transformers, Italian-make in stage I and Japanese in stage II are mounted on the same floor. The 2nd floor has the shaft section where the breaking system can be observed. Automatic controls and computerised monitoring are present on all sections. Several parameters like speed of turbine rotation, temperature of windings, output power levels and other things can be seen by the click of a mouse. There are auxiliary generators for excitation purpose and a DC power system to operate electronic equipment related to control and relay.
