Power Research

N. Maheswara Rao ¹, B. R. Vasudevamurthy ¹, Swaraj Kumar Das ¹, B. V. Raghavaiah ¹

Affiliations
1 Short-circuit Laboratory, Central Power Research Institute, Sir CV Raman Road, Bengaluru - 560080, IN

Abstract

The earth electrode is the main component of the earthing system which is in direct contact with the ground and thus provides a means of releasing or collecting any earth leakage currents. The electrode shall have good electrical conductivity and shall not corrode in a wide range of soil conditions. The design of these electrodes shall be such that they have good current carrying capacity under the earth fault conditions. This paper describes current withstand capability of these Earth Electrodes during earth fault conditions. Recent developments in Electrodes and their performance for different fault currents are given. Failure cases are studied from the laboratory tested Electrodes and appropriate recommendations were proposed. This can give an insight for estimating fault current withstand capability of a given dia and material of Electrode. Also different filler materials used for earth electrodes have been discussed.

Keywords

Earth Electrode, Pipe, Strip, Pipe in pipe, Strip in pipe, Short-circuit current, Coating Thickness Measurement, Touch Potential.

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S. Arjuna Rao ¹, Swaraj Kumar Das ¹, B. V. Raghavaiah ²

Affiliations
1 Short Circuit laboratory, Central Power Research Institute, Bangalore – 560 080, IN
2 Switchgear Testing & Development Station, Central Power Research Institute, Bhopal- 462 023, IN

Abstract

The development of wind power in India began in the 1990s, and has significantly increased in the last few years.India has the fifth largest installed wind power capacity in the world.As of 31 Jan 2013 the installed capacity of wind power in India was 18551.7 MW, mainly spread across Tamil Nadu (7134 MW), Gujarat (2,884 MW), &Maharashtra (2310.70 MW)whichare leading the top. All across the world, the demand for electricity from renewable energies is constantly growing. To meet this demand, wind farms must be as operable as conventional power plants and better integrated into the grid control mechanism. Our wind power plants should actively support the grid, fulfilling all necessary requirements and ensuring reliable energy supplies even during breakdowns. Wind power plants feed the grid with controlled reactive power. This allows for a constant voltage control, sustaining the line voltage. Even at temporary voltage dips the wind power plant remains connected to the grid and helps to keep it stable. If any frequency fluctuations occur the effective power of our wind turbines should automatically adjust according to the needs.

Keywords

Renewable Energy (RE),Wind Turbine Generator(WTG),Wind Power Plant(WPP),Doubly Fed Induction Generator (DFIG), Dynamic Voltage Restorer

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Maheswara Rao N. ¹, Girija G. ¹, Vasudevamurthy B. R. ¹, Swaraj Kumar Das ¹

Affiliations
1 Short Circuit Laboratory, CPRI, Prof. Sir C.V.Raman Road, Sadashivanagar, P.B.No. 8066, Bangalore - 560 080, IN

Abstract

This paper describes short circuit withstand capability of Bus-bar assembly panels and the significance of Bus-bar support structures commercially available in use. Recent developments in Bus-bar support structures for assembly panels are also discussed. The performance comparisons of these support structures under the Short-circuit currents were given. Few failure cases are studied from the laboratory tested panels and appropriate recommendations were proposed. This can give an insight, while selecting the suitable bus-bars support structure. Theoretical Force calculations were compared for different Bus-bar geometrical configurations.

Keywords

Bus-bar Assembly Panels, Bus-bar Support Structures, Short-circuit Currents and Theoretical Force Calculations

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Arjuna Rao S. ¹, Swaraj Kumar Das ¹, Raghavaiah B. V. ²

Affiliations
1 Short Circuit laboratory, Central Power Research Institute, Bangalore - 560 080, IN
2 Switchgear Testing & Development Station, Central Power Research Institute, Bhopal - 462 023, IN

Abstract

Cold rolled grain oriented (CRGO) electrical steel is a critical raw material for manufacturing of transformers, which is fully imported as it is not manufactured in India. Currently India consumes about 2.5 lakh metric tonne per annum of CRGO electrical steel and with the growth in demand of transformation capacity the consumption is estimated to be 11.5 lakh metric tonne and 13.5 lakh metric tonne respectively during the 12th and 13th five-year plan period. Magnetic cores for the wide range of modern electrical and electronic devices require magnetic materials with many combinations of properties and characteristics. The evaluation of magnetic core materials is very crucial before using for transformers, motors and Inductors.

Keywords

Grain oriented steel (GOs), Non-grain oriented steel (NGOs), Iron loss, Elastic & plastic stress and Ductility

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