Avdhesh kumar NIET PPT

1. PRESENTAION OF
GRID SUB-STATION
BY-
AVDHESH KU.MEENA

3.  Generating Station
 Transmission Line
 Sub-Stations

4.  Classification based on voltage levels, e.g. :
A.C. Substation : EHV, HV, MV, LV; HVDC
Substation.
 Classification based on Outdoor or Indoor :
Outdoor substation is under open sky. Indoor
substation is inside a building.

5.  Primary Substations receive power from EHV
lines at 400KV, 220KV, 132KV and transform the
voltage to 66KV, 33KV or 22KV to suit the local
requirements .
 Secondary Substations receive power at 66/33KV
which is stepped down usually to 11KV.
 Distribution Substations receive power at 11KV,
6.6 KV and step down to a volt suitable for LV
distribution purposes, normally at 415 volts


7. ELECTRICAL
TRANSMISSION
LINE

8.  Electrical transmission system is
the means of transmitting power
from generating station to
different load centres.

10.  Conductor
 Earth wire
 Insulator
 Transmission Tower
 Wave trap and other hardware(Clamp,
Spacer, Vibration dampers, connectors etc.

12.  Used to reduce earth wire potential and stress on
insulators at the time of stroke and also for safety
 Tower footing resistance will be 10Ω and should not
be more than 20 Ω under any condition throughout
the year.
 Earth resistance depend upon soil
resistivity(general 100 Ω-m)

13.  It provides a surface under the substation which has
uniform potential nearly equal to zero or Absolute
Earth Potential.
 It is of two types
o Neutral Earthing
o Equipment Body Earthing

15.  Earth wire provided above the
phase conductor across the line
and grounded at every tower.

16. tIA  5
Where A= Area(in mm2) of conductor
I =current in KA
T = Time in second
Area of Steel Wire = 3*A(mm2)
 For EHV line it is suggested as 70 mm2 (7/3.66
mm).
 ACSR is used as earth wire (12/3.0 mm AL+7/3.0
mm steel)

17. Optical Ground Wire
Advantages :
 Serves the dual purpose of ground wire
and communication.
 High speed data transmission.

20.  Major power station= 0.5 Ohm.
 Major Sub-stations= 1.0 Ohm
 Minor Sub-station = 2 Ohm
 Neutral Bushing. =2 Ohm
 Service connection = 4 Ohm
 Medium Voltage Network =2 Ohm
 L.T.Lightening Arrestor= 4 Ohm
 L.T.Pole= 5 Ohm
 H.T.Pole =10 Ohm
 Tower =20-30 Ohm

23.  Mechanical Requirement
 Electrical Requirement
 Mechanical Requirement
 Tensile Strength(For Tension)
 Strain Strength(For Vibration)

25.  Insulator are required to
support the line conductor and
provide clearance from ground
and structure.

29.  A Transformer is a static
device that transfers Electrical
energy from one Electrical
circuit to another Electrical
circuit by means of a common
Magnetic Circuit.


30. TRANSFORMER USED IN GSS
 POWER X-MER
 C.T.
 P.T.
 STATION X-MER

32.  To step-down the voltage and
transfer power from one A.C
voltage to another A.C Voltage at
same frequency

41. THANK YOU