2. 9/22/2023
Over view
Switching Schemes.
Line Towers.
Type of conductors.
Switchyard types.
Switchyard equipments.
Switchyard Layouts.
3. 9/22/2023
Switching schemes
Single bus.
Main and Transfer (sectionalised).
Double bus.
One and half breaker scheme.
Double main and Transfer
(Sectionalised).
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Switchyard Equipments.
Circuit Breaker.
Disconnectors.
Current Transformers.
Capacitor Voltage Transformers.
Lightning Arrestors.
Post Insulators.
Wave Traps
12. 9/22/2023
General Parameters
Dielectric Parameters .(IEC 694)
- Power Frequency Voltage.
- Lightning Impulse Voltage.
- Switching Impulse Voltage.
- Corona Extinction Voltage.
- RIV Level.
13. 9/22/2023
400kV Equipments
a. Rated voltage 420 kV
b. Rated frequency 50 Hz
c. Rated short time withstand
current capacity
40 kA rms for one (1) second
d. Insulation levels for 420kV Circuit
breakers and Disconnecting
Switches
e. i) Rated one minute power
Frequency withstand voltage
a) 520 kV rms between live
terminals and earth.
b) 610 kV rms across isolating
distance.
ii) Rated lightning impulse
withstand voltage
a) +/- 1425 kVp between live terminals
and earth.
b) +/- 1425 kVp impulse on one
terminal and 240 kVp power
frequency of opposite polarity on
other terminal (across isolating
distance).
iii) Rated switching impulse
withstand voltage
a) +/- 1050 kVp between live
terminals and earth.
b) +/- 900 kVp impulse on one
terminal and 345 kVp power
frequency of opposite polarity on
other terminal (across isolating
distance).
f. Max. Radio interference voltage
at 266kVrms
1000 micro volts for frequency
between 0.5 Mhz and 2.0 Mhz for all
equipment. However, for insulator
strings the measurement would be
at 305 kV .
g. Corona extinction voltage Not less than 320 kV rms
14. 9/22/2023
220kV Equipments
a. Rated voltage 245 kV
b. Rated frequency 50 Hz
c. Rated short time withstand
current capacity
40 kA rms for one (1) second
d. Insulation levels for 245kV Circuit
breakers and Disconnecting
Switches
e. i) Rated one minute power
Frequency withstand voltage
a) 460 kV rms between live
terminals and earth.
b) 460 kV rms across isolating
distance.
ii) Rated lightning impulse
withstand voltage
a) +/- 1050 kVp between live
terminals and earth.
b) +/- 1050 kVp impulse on one
terminal and other terminal
earthed (across isolating
distance).
f. Max. Radio interference voltage
at 156kVrms
1000 micro volts for frequency
between 0.5 Mhz and 2.0 Mhz for all
equipment.
15. 9/22/2023
132kV Equipments
a. Rated voltage 145 kV
b. Rated frequency 50 Hz
c. Rated short time withstand
current capacity
31.5 kA rms for one (1) second
d. Insulation levels for 145kV Circuit
breakers and Disconnecting
Switches
e. i) Rated one minute power
Frequency withstand voltage
a) 275 kV rms between live
terminals and earth.
b) 275 kV rms across isolating
distance.
ii) Rated lightning impulse
withstand voltage
a) +/- 460 kVp between live
terminals and earth.
b) +/- 460 kVp impulse on one
terminal and other terminal
earthed (across isolating
distance).
f. Max. Radio interference voltage
at 92kVrms
1000 micro volts for frequency
between 0.5 Mhz and 2.0 Mhz for all
equipment.
24. 9/22/2023
Wave Trap
Rated Inductance(0.5/1.0 mH).
Rated current.
Band Width.
Coupling (Phase to Phase).
25. 9/22/2023
Switchyard Layout Guidelines
Place All Equpt. At ground level for ease of
maintenance.
Busbars placed at right angles to feeders.
Accessibility of feeders from either side of
switchyard.
Conductor crossings at right angles be
separated to achieve adequate clearances.
27. 9/22/2023
Switchyard Layout
Guidelines(Contd.)
Lower level connections can be of Rigid pipe or
flexible conductor.
Upper level connections can be of strung type
only.
For aesthetic looks and similarity all same
equipments be in one line as far as possible.
Road near circuit breaker be kept for
maintenance purpose.
28. 9/22/2023
Switchyard Layout
Guidelines(Contd.)
Provide Double insulator strings for upper level
for safety reasons and to avoid busfaults due to
conductor snapping.
Cable trenches to be routed for ease in
maintenance and movement.
Lightning protection to be provided using
Lightning masts and/or shield wires.
Lighting to be provided by fixtures on LM platform.