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HVDS is acronym for High Voltage Distribution System. This system is being implemented exclusively for giving supply to agriculture connections on selected 11KV agriculture feeders. Implementation of HVDS involves conversion of Low Voltage Distribution System to High Voltage Distribution System – HVDS by replacing the existing 415V LT line to 11KV HT line and replacing the higher capacity (100/63KVA) Distribution Transformers (also known as “mother DTR”) with lower capacity (25KVA) Distribution Transformers.

In HVDS system, LT overhead line is completely avoided and instead LT AB cable is used from DTR up to consumer agriculture bore well, thus eliminating LT line faults 100%.

Presently in CPDCL during 2013-14, the HVDS project implementation agreements are being finalized in December 2013 and works are just grounded. Present HVDS project is being implemented with funds from JICA (Japan International Cooperation Agency).


Features
Survey of the existing 11KV agriculture feeder proposed for conversion to HVDS, mapping the 100/63KVA DTRs, mapping of associated LT lines, agriculture service connections details etc., Preparation of existing lines sketches, proposed sketches for HVDS conversion indicating mother DTR (higher capacity) and proposed DTRs (small capacity) & services.
Conversion of existing LT system in to 11KV system by replacing LT  X-arms, insulators etc., with 11KV X-arms, insulators using the same 34 Sqmm conductor. Worn out conductor will be replaced with new 34 Sqmm AAAC conductor.

  • Erecting intermediate new poles where ever existing span is loose.
  • Erecting 25KVA DTR on 9.1M PSCC pole on 75×40 mm channel support (pole mounted DTR) and erecting 3 x 1 Core XLPE 50 Sqmm cable for phase & 1 No. 25 Sqmm XLPE cable for neutral for LT.
  • Providing DTR earthing with 2 Nos 50 mm diameter CI Pipe of 2 meter length with 25 x 3 mm GI earth strip.
  • Erecting 11KV & LT HG fuse sets.
  • Extending service connections to three consumers with 3 x 16 + 25 Sqmm LT AB cable from DTR up to agriculture bore well.  A 25KVA DTR can be loaded maximum upto of its capacity.
  • Erecting of single phase LT -/5A electronic meter with meter box with 50/5A CT.
  • Painting the structure code and service numbers on the pole. And also painting pole numbers on poles on black background with white letters.
  • Devolution of 100/63KVA mother DTRs, removed LT hardware etc., to stores.


Advantages:

  • Reduction in line losses since HV line is taken almost up to consumer load point and on LV side AB cable is used.
  • Failure of agriculture DTRs are minimized as LT overhead line is avoided and also load  per DTR is restricted. Hence, no failure on account of over load and LT faults.
  • Reduction of unauthorized agriculture connections, as one small capacity (25KVA) DTR is erected for two or three agriculture consumers. The agriculture consumers will have a feeling of ownership of transformer due to limited connections on it.
  • As 11KV line is taken almost to the load point, improvement in voltage profile near agriculture pump sets is observed resulting in good performance of motor.
  • Pilferage of electricity is completely avoided as LT AB cable is used from DTR LV up to consumer bore well.

Pole mounted 25KVA HVDS DTR structure is as follows….

HVDS

By Er. Raja Sekharam. O
Divisional Engineer/Construction/Medak

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