INTRODUCTION

HVDS project is to reconfigure the existing Low voltage (LV) network asHigh Voltage Distribution System, wherein the 11KV line is taken as nearto the loads as possible and the LV power supply is fed by providing anappropriate capacity transformer and minimum length of LV line with anobjective to provide better quality power supply, reduction of losses andbetter consumer service. In the present system large capacity transformers areprovided at one point and the connections to each load is extended throughLV lines. This high length of LV lines is causing low voltage condition to themajority of the consumers and high technical losses. In the HVDS project,long length LV mains are converted into 11 kV mains and thereby installingthe appropriate capacity distribution transformer, the supply is provided toend consumer at usable voltage level. By converting these lines to HVDS,the current flowing through the lines shall reduce by 28 times and will bringdown the technical losses in the LV line drastically.The prevailing low voltage in the LV line is also affecting the efficiency ofthe electric gadgets and breakdown is also very high. Alsothere is a tendency of unauthorized connections to hook to the LVlines which results in over loading of the transformers and failure of thetransformers. The scheme consists of converting the existing 3phase 4 wireslines to 11 KV systems using the existing supports and providingintermediate poles wherever necessary and individual transformers areprovided to both agricultural loads and loads other than agriculture. Thelength of the LV lines is restricted to less than 300 meters.The benefits of the scheme are as follows:

1. Reduction in technical losses at LV lines.2. Improved voltage profile3. Arrest of commercial losses by avoiding unauthorized IP set connectionsand elimination of theft of energy.4. Energy savings due to improved efficiency of pump setsconsequent to better voltage profile.5. Involvement of consumer(s) in safety and upkeep of the DTCsdue to installation of dedicated transformer.6. Drastic reduction in Transformer failure.

Phase to Phase HVDS system has been adopted The constraints and limitations in case of SWER (Single Wire Earth Return),like presence ofstep and touch earthingpotential which can be a potential danger to the life in proximity in case of break in earth.In order to avoid this constraint of SWER,Phase to Phase HVDS system is adopted. It is proposed that25KVA transformers be provided taking into consideration that the capacity of each Domestic connection is around 3 to 7 KW in most of the cases and to accommodate future loads if any as a buffer. Use of transformers below 25KVA is found to be not feasible as they are copper wound and not cost effective. Besides, such transformers are highly prone to thefts. Single poles mounting design is adopted for the DTC which the prevailing practice in HVDS.