Sub Station Abstracts
June 8, 2011 34 Comments
Sub Station Equipments and Safety Clearance
Rating of Lighting Arrestor:
- Size of L.A = 1.5 X Phase to Earth Voltage OR
- Size of L.A =1.5 X system Voltage/1.732 OR
- Size of L.A = 0.81 X highest System Voltage
Lighting Arrestor Protection Radius:
- Protection Radius (Rp) = Sqrt (H X (2D-H)+L(2D+L))
- H= Actual Height of L.A
- D= 20 meter, 40 meter or 60 meter
- L= V X T (T=Discharge Time & V= 1m/ms)
Creepage Distance:
- 18 mm to 22 mm /KV for Moderate Polluted Air.
- 25 mm to 33 mm /KV for Heavily Polluted Air.
- In HVDC System The value is double from above value.
Lighting Arrestor Rating:
|
Rated Voltage |
Highest Voltage |
L.A Rating |
|
132kv |
145kv |
120kv To 132kv |
|
220kv |
245kv |
198kv To 216kv |
|
400kv |
420kv |
336kv |
Location of Lighting Arrestor:
|
Rated Voltage |
Max Distance from Equipment |
|
132kv |
35 meter To 45 meter |
|
220kv |
Closed To Transformer |
|
400kv |
Closed To Transformer |
Size of Corona Ring:
|
Rated Voltage |
Size of Corona Ring |
|
Less than 170 KV |
160mm Ring Put on HV end |
|
170KV To 275KV |
350mm Ring Put on HV end |
|
More than 275KV |
450mm Ring Put on HV end |
|
More than 275KV |
350mm Ring Put on HV end |
Capacity of Sub Station as per GERC:
|
Size of S/S |
Electrical Load |
|
66 KV |
80 MVA |
|
132 KV |
150 MVA |
|
220 KV |
320 MVA |
|
400 KV |
1000 MVA |
Breaking / Short Circuit Capacity of Sub Station:
|
Size of S/S |
Short Circuit Current |
|
66 KV |
25 KAmp for 1 or 3 sec |
|
132 KV |
31.5 KAmp for 1 or 3 sec |
|
220 KV |
40 KAmp for 1 or 3 sec |
|
400 KV |
40 KAmp for 1 or 3 sec |
Fault Clear Time:
|
Size of S/S |
Fault Clear Time |
|
66 KV |
300 mili Sec |
|
132 KV |
160 mili Sec |
|
220 KV |
120 mili Sec |
|
400 KV |
100 mili Sec |
Normal Type of Conductors:
|
Voltage |
Main Bus |
Auxiliary Bus |
|
11KV |
Twin ACSR Zebra |
ACSR Zebra |
|
33KV |
ACSR Zebra |
ACSR Zebra |
|
132KV |
ACSR Zebra |
ACSR Panthers |
|
220KV |
Twin ACSR Zebra |
ACSR Zebra |
|
400KV |
1/14.2 mm Dia Alu Pipe |
Twin ACSR Moose |
Number of Disc Insulator:
|
System |
Number |
Strength (KN) |
|
11KV |
4 |
120KN |
|
33KV |
4 |
120KN |
|
132KV |
10 |
120KN |
|
220KV |
14 |
70KN |
|
220KV (Anti Fog) |
2 X 15 |
120KN |
|
400KV (Anti Fog) |
2 X 25 |
120KN |
Minimum Clearance:
|
Voltage |
Phase to Earth Wire |
Phase to Phase |
Section Clearance |
|
2.2KV |
28cm |
33cm |
27.45cm |
|
33KV |
380cm |
43cm |
27.7cm |
|
132KV |
107cm |
12cm |
25cm |
|
220KV |
178cm |
20.6cm |
42.8cm |
|
400KV |
350cm |
40cm |
65cm |
Ground Clearance:
|
Voltage |
Meter |
|
33KV |
3.7meter |
|
66 KV |
6.1meter |
|
132 KV |
6.1meter |
|
220 KV |
7.0meter |
|
400 KV |
8.8meter |
Conductor Spacing:
|
Voltage |
Highest Voltage |
Lighting Impulse Level (Kvp) |
Min Clearance |
Ground Clearance |
Safety working Clearance |
|
|
Phase to Earth |
Phase to Phase |
|||||
|
11KV |
12kv |
70 |
178mm |
229mm |
3700mm |
2600mm |
|
33KV |
36kv |
170 |
320mm |
320mm |
3700mm |
2800mm |
|
132 KV |
145kv |
550 |
1300mm |
1300mm |
4600mm |
3700mm |
|
220 KV |
245kv |
950 |
2100mm |
2100mm |
5500mm |
4300mm |
|
400 KV |
420kv |
1425 |
3400mm |
4200mm |
8000mm |
6400mm |
Earthing Resistance Value:
|
Particular |
Max Earthing Resistance |
|
Power Station |
0.5Ω |
|
EHT Sub Station |
1Ω |
|
33KV Sub Station |
2Ω |
|
Double Pole Structure |
5Ω |
|
Tower foot Resistance |
10Ω |
|
Distribution Transformer |
5Ω |
|
220KV Sub Station |
1Ω To 2Ω |
|
400KV Sub Station |
0.5Ω |
Losses in 11 kv Transformer at 75c (As per CBIP):
|
Transformer |
No Load Loss(kw) |
Load Loss (kw) |
% Impedance |
|
3.15MVA |
2.9 |
20 |
6.25 |
|
4MVA |
3.2 |
27 |
7.15 |
|
5.3MVA |
3.9 |
31 |
7.15 |
|
6.3MVA |
4.5 |
37 |
7.15 |
Losses in 66 kv Transformer at 75c (As per CBIP):
|
Transformer |
No Load Loss(kw) |
Load Loss (kw) |
% Impedance |
|
6.3MVA |
6 |
40 |
8.35 |
|
8MVA |
7.1 |
48 |
8.35 |
|
10MVA |
8.4 |
57 |
8.35 |
|
12.5MVA |
9.7 |
70 |
8.35 |
|
20MVA |
13 |
102 |
10.0 |
Standard Rating of 66KV Transformer (As per CBIP):
|
Transformer |
KV |
Type of Cooling |
|
6.3MVA |
66KV/11KV |
ONAN |
|
8MVA |
66KV/11KV |
ONAN |
|
10MVA |
66KV/11KV |
ONAN |
|
12.5MVA |
66KV/11KV |
ONAN / ONAF |
|
20MVA |
66KV/11KV |
ONAN / ONAF |
% Impedance for Transformer (As per IS 2026):
|
33KV Transformer |
66KV Transformer |
||
|
MVA |
%Impedance |
MVA |
%Impedance |
|
1MVA |
5% |
6.3MVA |
8.35% |
|
1.6MVA |
6.25% |
8MVA |
8.35% |
|
3.15MVA |
6.25% |
10MVA |
8.35% |
|
4MVA |
7.15% |
12.5MVA |
8.35% |
|
5MVA |
7.15% |
20MVA |
10% |
|
6.3MVA |
7.15% |
16MVA |
10% |
|
8MVA |
8.35% |
25MVA |
10% |
|
10MVA |
8.35% |
31.5MVA |
12.5% |
|
MVA |
%impedance |
|
Less Than 1MVA |
5% |
|
1MVA To 2.5MVA |
6% |
|
2.5MVA To 5MVA |
7% |
|
5MVA To 7MVA |
8% |
|
7MVA To 12MVA |
9% |
|
12MVA To 30MVA |
10% |
|
More Than 30MVA |
12.5% |
Bus Bar Materials:
| Description | Bus Bar and Jumper Material |
| 400 kV Main Bus | 114.2 mm dia. Aluminium pipe |
| 400 kV equipment interconnection | 114.2 mm dia. Aluminium pipe |
| 400 kV overhead bus & droppers in all bays. | Twin ACSR Moose |
| 220 kV Main Bus | Quadruple / Twin ACSR Zebra / Twin AAC Tarantulla |
| 220 kV Auxiliary Bus | ACSR Zebra |
| 220 kV equipment interconnection | Twin ACSR Zebra / Single ACSR Zebra |
| 220 kV overhead bus & droppers in all bays. | Twin ACSR Zebra / Single ACSR Zebra |
| 132 kV Main Bus | ACSR Zebra |
| 132 kV Auxiliary Bus | ACSR Panther |
| 132 kV equipment interconnection | ACSR Zebra / ACSR Panther |
| 132 kV overhead bus & droppers in all bays. | ACSR Panther |
| 33 kV Main Bus | ACSR Zebra |
| 33 kV Auxiliary Bus | ACSR Zebra |
| 33 kV equipment interconnection, overhead bus and droppers: | |
| (i) Bus coupler & transformer bay | ACSR Zebra |
| (ii) Feeder bay. | ACSR Panther |
| 11 kV Main Bus | Twin ACSR Zebra |
| 11 kV Auxiliary Bus | ACSR Zebra |
| 11 kV equipment interconnection, overhead bus and droppers: | |
| (i) Transformer bay | Twin ACSR Zebra / Single ACSR Zebra |
| (ii) Bus coupler | ACSR Zebra |
JIGNESH PARMAR
Thank u very much for providing valuable material. It is very helpful to me.
Thanks for this upload
Thanks a lot Mr: Jignesh. The datas was very helpful
Asif KM
Saudi Electricity Company
very very good!!!
very helpful..
I have request could you please provide the standard/code reference for Earthing Resistance Values.
Thanks in advance.
Earthing Resistance Value:
Power Station = 0.5 ohm.
Sub Station Major=1.0 ohm.
Sub Station Minor=2.0 ohm.
Distribution T/C=5.0 ohm.
Transmission Line=10 ohm.
As per My knowledge.There is not exact value for Earthing Resistance in any Standard ,It depend upon Soil but There is a guideline in Some Code that it should be less than 5 ohm and in some code it is given less than 10 ohm.
sir, what is your reference standard here ?
hi!
i want know how to calculate the LA (lightining Arrestor) rated voltage.
any formula
Would you please to told me what’s meaning GERC and CBIP??
Thanks a lot
GERC =Gujarat electricity Regulation Commission
CBIP=Central Beau of Irrigation and Power
Its very good. Thank you very much.
could i get a detailed article on power transformer testing including the purpose
hi
VERY INFORMATIVE .PLEASE PROVIDE INFORMATION ABOUT PROTECTION DIAGRAMS
Dear Sir , we are thankful to you for the exhaustive information u provide in collective manner. Pl provide some article on DC Battery chargers & DC Batteries used in EHV sub stations.
Thank u, it is very useful
than u ,
i need megger value is any standard.
Do you have any formula for calculate clearance phase to phase ,phase to earth ,sectional clearance without reference of standards
Not for have Formula for Phase to Phase but For Grounding Clearance You may use
Ground Clearance:
CL= 5.812 + 0.305 X K
CL= Ground Clearance in Meter.
K= (Volt-33)/33
hello sir,
I would like to go through a simplified, detailed substation design procedure guide. Please help me in this regard.
can u tell me about sub conductor spacing in twin zebra conductor
Dear Sir
thank you for above article
can you please tell or mail me the types of tests performed in substation or detailed notes on testing and commissioning methods carried din substation
dear sir, i need your help i am doing a 220 kV s/s project in tanzinia pl tell me what Clarence i should kept . can i used CBIP ???
i need one information why choose in twin conductor in susstation
dear sir,
i need the substation design calculation formula
Sir how the ratings of lightning arrester is decided????
I very much appreciate the valuable data being provided by you and your knowledge. Please respond to my following queries:
1. Why 02 nos. Surge Arresters are normally used in a 145 kV or more voltage level in a single bay of GIS switch-gear?
2. Kindly also refer international applicable standard(s) against values/data being provided by you.
Regards,
Waqas Khalid
Sir name And type of holo conductor used in 132 KV yard
hii sir i think there is some mistakes in minimum clearance table ( 400 KV phase to phase clearance only 40 cm and in 220kv 20 cm and in 132kv 12cm )
Thanks for your valuable information
Size of L.A =1.5 X system Voltage/1.732 , why we have to multiple 1.5?
please tell me the minimum distance between tower and gantry with rule
What is the minimum ground clearance from 5MVA power transformer bushings