40 NATIONAL POWER SYSTEMS CONFERENCE, NPSC 2002 Prospect of Power Generation-A Pumped Storage Scheme at Chikhaldara - State

S. W. Mohod D. T. Ingole S. M. Kelo

ABSTRACT:--The paper describes the pumped storage scheme II. PROPOSED PUMPED STORAGE SCHEME AT to generate a power of 400 MW to meet the peak system CHIKHALDARA (400 MW) demand. The proposed pumped storage scheme has ability to fulfill the availability of spinning reservoir in the off peak load which improves the overall performance of thermal power The proposed pumped storage schemes seem to be station in the integrated system. The pumped storage scheme the ideal choice for meeting the gap between demand and based on economics of operation and the availability of enough availability. The pumped storage schemes give extra night spare capacity in the grid to operate the machines as pump in load reducing the backing down of thermal stations and will low demand period. The schemes convert the low value off peak assist the power system in meeting the day peaks resulting in energy into the high value, on peak capacity and energy. The scheme is helpful in development of Agricultural, overall economy in capital investments at a little extra cost in Industrial, Commercial field and will also improve the living fuel. standard of tribal people in the surrounding area. [ 1 ] It is mentioned that peak demand by 2000-01 was 15113 MW. Total effective capacity that would be available I. INTRODUCTION by 2000-01 from thermal, nuclear and gas turbines is 9732 MW. Night load expected would be of the order of 7258 Mw., which would involve backing down of 2474 MW. of The state of Maharashtra has been facing power thermal capacity. For so backing down, the thermal units shortage for the last few schemes have been cleared and are need oil firing to keep them hot so that, they could be brought under execution, the power requirements may not be meet on bars to meet these peak demands during the day. This is a fully due to ever growing power demand of the state. Due to very costly proposition. daily load variation, the thermal stations are required to be It may be appreciated that no technical solution is backed down during off peak hours i.e., nighttime, thus available to this problem unless the capacity can be utilised. resulting in under utilisation and at higher cost of generation. This can be achieved very rapidly by introduction of pumped If the difference between the day peak and night load is storage schemes only. The addition of pumping load during sufficiently large the thermal stations will either have to be off peak period will thus reduces backing down of thermal closed down completely or operated on very low load plants and costly oil firing. It will also improve efficiency of requiring oil firing to keep the boilers running for bringing it thermal plants during off peak period thereby reducing the up during the day to meet the demand. Such operation is not cost of generation of these thermal plants. All the above only undesirable but also uneconomical. benefits attributable to pumped storage schemes however The pumped storage scheme give sufficient night cannot readily be evaluated in terms of monetary benefits [3]. load so that backing down of thermal stations is reduced and In this contest, it is proposed to consider pumped thus assist the system for meeting the day peak resulting in storages scheme at Chikhaldara in Maharashtra State having overall economy in the power sector. an installed capacity of 400MW at 25% load factor. This The pumped storage installation stores energy project will generate about 2.4 million unit during a peak day. during off peak periods to be used for generation during peak Planning some more pumped storage scheme could further demand periods. Water is pumped from a lower reservoir to bridge the gap in effective capacity still left over. an upper reservoir during off peak period. Stored water is later on used to generate power to meet the system peak III. WATER CONDUCTOR SYSTEM demand. The pumped storage scheme has the ability to fill In between higher elevated reservoirs and lower the availability of spinning reservoir in the off peak load reservoirs water conductor system is planned to generate the which improves the overall performance of thermal power power by drawing water from higher elevated reservoir. The stations in the system. Thus pumped storage systems fulfil the water conductor system consists of - coverage of peak load in generating phase. 1. Intake structure 2. Pressure Shafts (tunnel). 3. Power- house. 4. Tail race

tunnel. 5. Feeder tunnel. S.W. Mohod, College of Engineering Badnera (C. Rly), Maharashtra e-mail : sharadmohod@ rediffmail.com , GENERATING PLANT: This being a pumped storage scheme, the essential D.T. Ingole, Professor, College of Engineering Badnera (C. Rly) e-mail : dt_ingole @hotmail.com component will have to operate as a generation station as well as pumping station. Various combinations can be made. S.M. Kelo, College of Engineering Badnera (C. Rly) , Maharashtra Separate machine for both the operation or INDIAN INSTITUTE OF TECHNOLOGY, KHARAGPUR 721302, DECEMBER 27-29, 2002 41

I) Unique electrical set and separate pump turbines or V. DESIGN CALCULATIONS II) Altogether reversible set. 1. Design Discharge ( Q ) Present world trend is towards the use of reversible unit.[2] Output power P =9.81 Q H η where P - The generator voltage is proposed to be 11 KV. All necessary capacity ( KW) H - Head (meter.),η -overall efficiency control and protective equipment will be provided to 2. Hence, Q = 138 m3 / sec. Quantity of water required synchronous machine to operate as generator and also as a to be stored for 6 hours of generation in a day = 2.98 M m3 / motor. The generator will be connected to the three-phase s. Pumping Discharge transformer located in upstream cavern by means of 11 KV isolated duct. This scheme envisages among other project Output in H.P. = W. H / 75 η ,where, W – Wt. of water to be lifted = 98.7 m3/s components the construction of two small reservoirs. There is 3 no village coming under the submergence of these reservoirs. 3. Time required for pumping of 2.98 Mm = 8.33 Moreover, this scheme does not have irrigation and hence Hours. will not lead to any water logging effect in the project area. The off-peak time available is 7 hours.[ 4 ] 3 The proposed project cost works out to be Rs. 515 crores.[ 3 ] Hence volume of water pumps in 7 hrs. = 2.4 Mm , Balance 3 water = 0.47 Mm ENERGY OF PUMPING: Time required for pumping the balance water = 8 hours, The scheme will utilize off peak energy for Hence total pumping hour = 50 Hours pumping. The cost of the fuel is calculated as 35 paise/unit for pumping energy. [4] SYSTEM LAYOUT

IV. PROJECT FEATURE OF PUMPED STORAGE SCHEME Surge Tank [5] LOCATION: The project site is about 105 Km. from , State– Penstock Maharastra, District – Amravati, Tunnel Upper Power House Upper dam Lower dam Dam Latitude 200-23|-10l l 210-22|-35 l l Longitude 770-21|-25 l l 770-21|-25 l l HYDROLOGY Rain gauge Station – Chikhaldara. 90% dependable Annual Rainfall – 46.14” Daily water Tail Race circulation – 2.98 Mm3 Peaking Discharge – 138 m3/s VI. CONCLUSION Live Storage: 6.270 Mm3 Maximum thermal power generation occur in Dead storage at Silt Level: 0.513 Mm3 region of Maharashtra state through Koradi CATCHMENT AREA Thermal Power Station, Chandrapur Thermal Power Station, Upper reservoir – 0.34 Sq. Km. Khaparkheda, Paras pumped storage. These thermal power Lower reservoir – 6.4 Sq. Km. stations are required to back down during off peak load SUBMERGENCE AREA period. The capacity thus available to pump back the water to Upper reservoir – 10.5 Hector upper reservoir of pumped storage scheme at minimum Lower reservoir – 34.75 Hector. transmission line loss. Hence it is always economical to DAM TYPE locate pumped storage scheme in the area of thermal power Upper & Lower Dam – Masonry type. station belt. In view of this, the proposed site at Chikhaldara INTAKE STRUCTURE in Maharashtra State is an ideal site and a boom to private R.C.C. Structures sector. PRESSURE SHAFTS VII. REFERENCES Number – 02nos. , Length – 671.05 M. , Diameter – 3.900 M. [ 1 ] A.K. Goyal, Small Hydro Power Project – Private Sector at the intake tapering Participation – Electrical , Annual-1996. POWER HOUSE [ 2 ] Mandle K.T., Dinorving Pumped Storage Station , Power Engineering Generator Capacity – 400 MW. Generation voltage – Journal, 259-262 , Sept. 1988. [ 3 ] Indian Journal of Power & River Valley Development , Oct. 87 , 240 11 K.V. Vol. XL1999. Design head – 341 m [ 4 ] Tariff – Reference Department Circular , 568 , M.S.E.B. , H.O. Turbine Type --Vertical shaft single stage reversible turbine. ,Mumbai Turbine Capacity –200 MW, 112 MVA [ 5 ] Project Report Vol. II – Aug. 1989 – Government of Maharashtra, Irrigation Department, Amravati , 27-55, 235-251. Daily generation operation for – 6 hour. Power factor – 0.9, Speed – 600 r.p.m. Daily hour of pumping – 7 hours.