Calculate Technical Losses of Transmission / Distribution Line:

Introduction:

  • There are two types of Losses in transmission and distribution Line.
  • (1) Technical Losses and
  • (2) Commercial Losses.
  • It is necessary to calculate technical and commercial losses.Normally Technical Losses and Commercial Losses are calculated separately .Transmission (Technical) Losses are directly effected on electrical  tariff but  Commercial losses are not implemented to all consumers.
  • Technical Losses of the Distribution line mostly depend upon Electrical Load, type and size of conductor, length of line etc.
  • Let’s try to calculate Technical Losses of one of following 11 KV Distribution Line

Example:

  • 11 KV Distribution Line have following parameter.
  • Main length of 11 KV Line is 6.18 Kms.
  • Total nos. of Distribution Transformer on Feeder 25 KVA= 3 No, 63 KVA =3 No,100KVA=1No.
  • 25KVA Transformer Iron Losses = 100 W, Copper Losses= 720 W, Average LT Line Loss= 63W.
  • 63KVA Transformer Iron Losses = 200 W, Copper Losses= 1300 W, Average LT Line Loss= 260W.
  • 100KVA Transformer Iron Losses = 290 W, Copper Losses= 1850 W, LT Line Loss= 1380W.
  • Maximum Amp is12 Amps.
  • Unit sent out during to feeder is  490335 Kwh
  • Unit sold out during from Feeder is 353592 Kwh
  • Normative Load diversity Factor for Urban feeder is 1.5 and for Rural Feeder is 2.0

Calculation:

Total Connected Load=No’s of Connected Transformer.

  • Total Connected Load= (25×3) + (63×3) + (100×1).
  • Total Connected Load=364 KVA.

 Peak Load = 1.732 x Line Voltage x Max Amp

  • Peak Load = 1.732x11x12
  • Peak Load =228 KVA.

 Diversity Factor (DF) = Connected Load (In KVA) / Peak Load.

  • Diversity Factor (DF) = 364 /228
  • Diversity Factor (DF) =1.15

 Load Factor (LF)= Unit Sent Out (In Kwh) / 1.732 x Line Voltage x Max Amp. x P.F. x 8760

  • Load Factor (LF)=490335 / 1.732x11x12x0.8×8760
  • Load Factor (LF)=0.3060

 Loss Load Factor (LLF)= (0.8 x LFx LF)+ (0.2 x LF)

  • Loss Load Factor (LLF)= ( 0.8 x 0.3060 x 0.3060 ) + (0.2 x 0.306)
  • Loss Load Factor (LLF)= 0.1361

 Calculation of Iron losses:

  • Total Annual Iron loss in Kwh =Iron Loss in Watts X Nos of TC on the feeder X8760 / 1000
  • Total Annual Iron loss (25KVA TC)=100x3x8760 /1000 =2628 Kwh
  • Total Annual Iron loss (63KVA TC)=200x3x8760 /1000 =5256 Kwh
  • Total Annual Iron loss (100KVA TC)=290x3x8760 /1000 =2540 Kwh
  • Total Annual Iron loss =2628+5256+2540 =10424Kwh

 Calculation of Copper losses:

  • Total Annual Copper loss in Kwh =Cu Loss in Watts XNos of TC on the feeder LFX LF X8760 / 1000
  • Total Annual Copper loss (25KVA TC)=720x3x0.3×0.3×8760 /1000 =1771 Kwh
  • Total Annual Copper loss (63KVA TC)=1300x3x0.3×0.3×8760 /1000 =3199 Kwh
  • Total Annual Copper loss (100KVA TC)=1850x1x0.3×0.3×8760 /1000 =1458 Kwh
  • Total Annual Copper loss =1771+3199+1458=6490Kwh

 HT Line Losses (Kwh)=0.105 x (Conn. Load x 2) x Length x Resistance x LLF /( LDF x DF x DF x 2 )

  • HT Line Losses= 1.05 x(265×2) x 6.18 x 0.54 x 0.1361 /1.5 x 1.15 x1.15 x 2
  • HT Line Losses = 831 Kwh

 Peak Power Losses= (3 x Total LT Line Losses) / (PPLxDFxDFx 1000)

  • Peak Power Losses= 3 x (3×63+3×260+1×1380) /1.15 x 1.15 x 1000
  • Peak Power Losses= 3.0

 LT Line Losses (Kwh)= (PPL.) x (LLF) x 8760

  • LT Line Losses = 3 x 0.1361 x 8760
  • LT Line Losses = 3315 Kwh

 Total Technical Losses= (HT Line Losses + LT Line Losses + Annual Cu Losses + Annual Iron Losses)

  • Total Technical Losses = ( 831+ 3315 + 10424 + 6490)
  • Total Technical Losses = 21061 Kwh

% Technical Loss= (Total Losses) / (Unit Sent Out Annually) x 100

  • % Technical Loss= (21061/490335) x100= 4.30%

% Technical Loss=4.30%

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About Jignesh.Parmar
Jignesh Parmar has completed his B.E(Electrical) from Gujarat University. He has more than 11 years experience in Power Transmission-Power Distribution-Electrical energy theft detection-Electrical Maintenance-Electrical Projects(Planning-Designing-coordination-Execution). He is Presently associate with one of the leading business group as a Assistant Manager at Ahmedabad,India. He is Freelancer Programmer of Advance Excel and design useful Excel Sheets of Electrical Engineering as per IS,NEC,IEC,IEEE codes. He is technical Author for "Electrical Mirror" and "Electrical India" Magazines. He is Technical Blogger and Familiar with English, Hindi, Gujarati, French languages. He wants to Share his experience & knowledge and help technical enthusiasts to find suitable solutions and updating themselves on various Engineering Topics.

9 Responses to Calculate Technical Losses of Transmission / Distribution Line:

  1. gustavo rafael faquira soto says:

    excelente…gracias…

    • joe c. says:

      Total Connected Load=364 KVA.

      Peak Load = 264 / 1.732x11x12
      Peak Load =228
      I think there is a mistake in the above if Total connected load =364KVA
      But peak load is calculated with 264KVA?
      please explain.
      Thanks

      • Dear Joe,

        It is typing mistake in peak load calculation
        connected load is 25KVA 3nos TC+ 63KVA 3NO TC + 100KVA 1No TC =25×3=63×3=100=364KVA
        and Peak Load is 1.732 x KV X Max.Amp=1.732x11x12 =228KVA
        Thanks for highlighting…

  2. PRASHANT SONI says:

    Thank you very very much for your valuable and noble help / service to other electrical engineers…

    As we know yyou have uploaded the article “11KV-415V OVERHEAD LINE SPECIFICATION (REC) ” That is very much useful and helpful to us…

    I kindly request oyu to upload an article like
    1) 66 kV – 11 kV OVERHEAD LINE SPECIFICATION (REC / CEA 2010 / IS STANDARDS / IE RULE1956) or GETCO specification
    2) 11KV-415V DISTRIBUTION SUBSTATION / POLE MOUNTED DTC SPECIFICATION (REC / CEA 2010 / IS STANDARDS / IE RULE1956)

    We all hope for your kind support and help…

    Thanking you in anticipation,

    Thanks & regards,
    Prashant Soni
    09998937121
    (Ahmedabad)
    prashant_k_soni@live.com

  3. PRASHANT SONI says:

    3) 66 kV – 11 kV SUB STATION SPECIFICATION (REC / CEA 2010 / IS STANDARDS / IE RULE1956) or GETCO specification

  4. PRASHANT SONI says:

    I would be glad to receive your affirmative response reply at your earliest possible convenience…

  5. shahbaaz says:

    may i know the technical loss on a 16 kms 11 kv double circuit feeder having dog conductor with a load of 10 mw transmitted direct on a bus bar of the grid station.. no distribution transformer installed in between sending point to receiving end i-e bus bar..hoping a positive response from your side.

  6. Hsu Mon Myint says:

    May I know the formula of finding HT losses (0.105 or 1.05).
    Now I m studying line loss reduction in distribution line.
    The above formulae are very useful for me.
    Thanks for ur sharing !

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