Overheal Line Clearances_IE Rules

REGULATION CONSTANTS FOR OVERHEAD LINES Three Phases 50 Hz per 100 KVA per Km Phase to Phase Voltage

Size of conductor in mm

EquiEquiResis valent valent tance alum- spacing at inium in 40 o c in area in meter Ohms/ Sq.mm km

Reactance in Ohms/ Km

Percentage Regulation constant for lagging P.F. 0.8

0.9

Unity

415 V

Gnat 7/2.21 mm AAC

16

0.483

1.1566

0.3330

65.33000

68.90000 67.08000

415 V

Ant 7/3.31 mm AAC

30

0.483

0.5879

0.3115

38.16000

38.57000 34.14000

11 KV

Squirel 7/2.11 mm ACSR

20

0.914

1.4750

0.3900

0.11690

0.12370

0.12190

11 KV

Weasel 7/2.59 mm ACSR

30

0.914

0.9770

0.3820

0.08400

0.08710

0.08150

11 KV

Mink 7/3.66 mm ACSR

40

0.914

0.4900

0.3650

0.05049

0.04958

0.04144

22 KV

Weasel 7/2.59 mm ACSR

30

1.066

0.9770

0.3920

0.02120

0.02180

0.02040

22 KV

Mink 7/3.66 mm ACSR

40

1.066

0.4900

0.3800

0.01290

0.01260

0.01020

33 KV

Weasel 7/2.59 mm ACSR

30

1.371

0.9770

0.4085

0.00950

0.00980

0.00910

33 KV

Mink 7/3.66 mm ACSR

40

1.371

0.4900

0.3980

0.00580

0.00570

0.00450

FORMULA FOR % V.R. CALCULATION FOR 11 KV , 22 KV & 33 KV LINES [ Es - Er ] % Voltage regulation

=

x 100 Es

Where, Es = Sending end voltage Er = Receiveing end voltage Er = Es - [ IR Cos Ø + IX Sin Ø]

S/S 500 KVA Percentage Voltage regulation at B for kva km between B & A = 500 x 2 kva km between A & SS = 1000 x 1 Total kva km = 1000 + 1000

500 KVA 11 = = =

KV feeder of Squirrel Conductor, 1000 1000 2000

Constant from table % Regulation = Total kva km x 100 2000 x 0.1211 =

= 2.422 % ( This should not exceed ± 6% for L.T. & ± 12% for H.T.) 100 1

FORMULA FOR CALCULATION FOR LINE LOSSES AS PER REC STANDARD 11 KV Line

33 KV Line

Average Energy Loss in feeder

Average Energy Loss in feeder in KWH

0.105 x L x R x P 2 x L.L.F.

= Peak power Loss x LLF x 8760

= 2 x LDF x (D.F.)

2

R = Resistance of Conductor per Km L = Length of Line in Km P = Total conducted load in KVA LLF = Loss load factor LF = Load factor of system D.F. = Diversity Factor L.D.F. = Load distribution factor L.L.F. = 0.8 x ( L.F.) 2 + 0.2 x (L.F.)

2

3xI

R

Peak Power Loss = 1000 Where R = Resistance of conductor per Km. I = Max current in the line.

LINE CLEARANCES The minimum clearances shall be in accordance with Indian Electricity Rules, 1956 and are given in Table I. Table - I, Minimum Clearance ( Values in Meters ) Voltage Category (IE Rules,1956) Nominal System Voltage Clearance

Low & Medium Voltage Low

Extra High Voltage

Upto Upto 66 KV 132 KV 220 KV 400 KV 11 KV 33 KV HVDC

±500 KV 800 KV

6.1 5.6 4.6 4.0

6.1 5.8 5.2 -

6.1 6.1 5.5 -

6.1 6.1 6.1 -

7.0 7.0 7.0 -

8.80 8.80 8.80 -

12.50 12.50 12.50 -

12.40 12.40 12.40 -

2.5

3.7

3.7

4.0

4.6

7.30

11.59

10.50

1.129

1.219

2.0

2.3

2.9

5.5 $ 3.80

5.6

10.98

9.20

1) Clearance to Ground (a) Across Street 5.8 (b) Along Street 5.5 (c) Other areas Bore Cond. 4.6 (d) Other areas Insu. cond. 4.0 2) Clearance to Buildings (a) Vertical (*) - from higher object (b) Horizantal (+) - from nearest point.

High Voltage

3) Clearance Between Line crossing each other. Voltage of 1 st Line

Voltage of 2 250V to 66KV

250 V to 66 KV 100 KV 132 KV 220 KV 400 KV + 500 KV HVDC 800 KV

2.44 2.75 3.05 4.58 5.49 6.86 7.94

100 KV

132 KV

2.75 2.75 3.05 4.58 5.49 6.86 7.94

3.05 3.05 3.05 4.58 5.49 6.86 7.94 2

220 KV 4.58 4.58 4.58 4.58 5.49 6.86 7.94

nd

Line 400 KV 5.49 5.49 5.49 5.49 5.49 6.86 7.94

± 500KV HVDC 6.86 6.86 6.86 6.86 6.86 6.86 7.94

800 KV 7.94 7.94 7.94 7.94 7.94 7.94 7.94