(27) Calculate No of Plate-Pipe Earthing (1.8.23).xlsx

	C	D	E	I	J	K	O	P
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2	Calculate Number of Plate / Pipe Earthing				Jignesh.Parmar, jiguparmar@yahoo.com www.electricalnotes.wordpress.com
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5	Calculate No of Plate Earthing			Calculate No of Pipe Earthing
6	As per IS 3043-1987			As per IS 3043-1987
7	Short circuit Current(Isc)	65000	Amp	Short circuit Current(Isc)	50000	Amp	Normal Short Circuit Value
8	Duration of Fault in sec (t)	1	Sec	Duration of Fault in sec (t)	1	Sec	440KV	40 KA for 1 to 3 Sec
9	Soil Resisitivity (ρ) If You Know (Otherwise Leave Blank)	100	Ω-Mt.	Soil Resisitivity (ρ) If You Know (Otherwise Leave Blank)	72.44	Ω-Mt.	220KV	40 KA for 1 to 3 Sec
10	Soil Resistivity	100	Ω-Mt.	Soil Resistivity	72.44	Ω-Mt.	132KV	35 KA for 1 to 3 Sec
11							66KV	25 KA for 1 to 3 Sec
12							11KV(Urban)	35 KA for 1 to 3 Sec
13							11KV(Rural)	25 KA for 1 to 3 Sec
14	Permissible Current Density at Earth Electrode (Id)	757	Amp/Sq.Mt	Permissible Current Density at Earth Electrode (Id)	889.42	Amp/Sq.Mt	415V	10 KA for 1 to 3 Sec
15	Permissible Earth Resistance of System	2	Ω	Permissible Earth Resistance of System	1	Ω	220V	6 KA for 1 to 3 Sec
16	Detail of Plate Earthing:			Detail of Pipe Earthing:
17	Plate Width	600	mm	Diameter of Pipe(d)	100	mm	Typical soil resistivity (IEEE 142 / BS 7430)
18	Plate Height	600	mm	Radius of GI Pipe(R.)	0.05	Mt.	Soil Type	Avg. Resistivity (Ω‐m)
19	Surface Area of both sides of plate(S)	0.72	Sq.Mt	length of Pipe(L)	3	Mt.	Well‐graded gravel	600 – 1000
20	Max.Current Dessipated by One Electrode	545.04	Amp	Surface Area(S)	0.943	Sq.Mt	Poorly graded gravel	1000 – 2500
21	Single Earth Plate Resistance	290.14	Ω	Max.Current Dessipated by One Electrode	838.37	Amp	Clayey gravel	200 – 400
22	No of Copper Plates Earthing Required	119	Nos	Single Cast Iron Pipe Resistance	18.408	Ω	Silty sand	100 – 800
23				No of Pipe Earthing Required	60	Nos	Clayey sands	50 – 200
24	Arrangement of Pipe Earthing	Parallel	1	Arrangement of Pipe Earthing	Parallel	1	Silty or clayey sand	30 – 80
25	Formation of Parallel Earthing (As per BS 7430):	Traingle		Formation of Parallel Earthing (As per BS 7430):	Hollow Sqare
26	Distance Betweem successive Electrodes (D)	8	Meter	Distance Betweem successive Electrodes (D)	8	Meter	Fine sandy soil	80 – 300
27	Overlall Earthing Resistance of 119 Nos of Electrodes	2.467	Ω	Overlall Earthing Resistance of 60 Nos of Electrodes	0.514	Ω	Gravelly clays	20 – 60
28	Whether Earthing Strip / Wire Buried in Ground	Yes		Whether Earthing Strip / Wire Buried in Ground	Yes		Inorganic clays	10 – 55
29	Earth Resistance of Buried Strip / Wire:			Earth Resistance of Buried Strip / Wire:			Surface Soils	1 ‐ 50
30	Strip Width(w):	12	mm	Strip Width(w):	12	mm	Clay	2 ‐ 100
31	Strip Length(L):	2200	Mt	Strip Length(L):	2200	Mt	Sandy clay	100 ‐ 150
32	Depth of Burial of Strip Electrode(t):	200	mm	Depth of Burial of Strip Electrode(t):	200	mm	Moist gravel	50 ‐ 700
33	Surface Area of both sides of Strip(S):	52.8	Sq.Mt	Surface Area of both sides of Strip(S):	52.8	Sq.Mt	Dry gravel	700 ‐ 1200
34	Max.Current Dessipated by One Electrode	0.00	Amp	Max.Current Dessipated by One Electrode	46961.35	Amp	Limestone	5 ‐ 10000
35	Resistance of Earthing Strip/Wire:	0.1601	Ω	Resistance of Earthing Strip/Wire:	0.1160	Ω	Porous limestone	30 ‐ 100
36	Results			Results			Quartz, limestone	100 ‐ 1000
37	No of Plate Earthing	119	Nos	No of Pipe Earthing	60	Nos	Sandstone	20 ‐ 2000
38	Arrangement of Plate Earthing	Parallel		Arrangement of Pipe Earthing	Parallel		Granites	900 ‐ 1100
39	Earthing Strip / Wire For Earthing Buried in Ground	Yes		Earthing Strip / Wire For Earthing Buried in Ground	Yes
40	Overlall Resistance of Earthing Plate	2.4666	Ω	Overlall Resistance of Earthing Pipe/Rod	0.5135	Ω
41	Resistance of Earthing Strip/Wire	0.1601	Ω	Resistance of Earthing Strip/Wire	0.1160	Ω
42	Total Earth Resistance of Plate Earthing & Earth Strip	0.1503	Ω	Total Earth Resistance of Pipe Earthing & Earth Strip	0.0946	Ω
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45	:Calculation:
46	Earthing Strip Size A=(IscX√t)/K
47	Current Density permissible at an Earth Electrode Id=(7.57*1000)/√(ρxt) Amps/Sqmeter
48	No of Plates required N=Isc/Id/S
49	Plate R=(ρ/S)*(√Π/S) Ohm
50	Pipe or Rod R= (100ρ/2ΠL)*log℮(4L/d)ohms
51	Stip or Conductor R=(100ρ/2ΠL)*log℮(2L²/wt) ohms
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