Substation design

“Design of 400/220kV
Sub-station”
S.M. MUJUMDAR

27th April 2005
Mumbai

General Manager
(sub-station Engineering)
Jyoti Structures Ltd.,

Agenda


Overview of 400kV sub-station



Design Process



Design considerations



Question / Answer

Imp. considerations in substation design







Safety of personnel and equipment
Reliability and Security
Adherence to
 Statutory obligations
– I.E. rules, Environmental aspects
 Electrical design considerations
 Structural design considerations
Ease of maintenance
Possibility to Expand

System parameters
Sr.

Description

400kV

220kV

1.

Nominal system voltage

400kV

220kV

2.

Max. operating voltage

420kV

245kV

3.

Rated frequency

50Hz

50Hz

4.

Number of phases

3

3

5.

System neutral earthing

Effectively earthed

6.

Corona Extinction voltage

320kV

156kV

7.

Min. creepage distance

25mm/kV

25mm/kV

8.

Rated short ckt. Current for 1 sec.

40kA

40kA

1000 mV
(320kV)

1000 mV
(156kV)

10. Radio interference voltage at 1MHZ
(for phase to earth voltage)

System parameters Contd..
Sr.

Description

400kV

220kV

11.

Rated insulation levels
i) Full wave impulse withstand voltage
-- for lines
-- for reactor/ X’mer
-- for other equipments

1550kVp
1300kVp
1425kVp

1050kVp
950kVp
1050kVp

ii) Switching impulse withstand voltage (dry/wet) iii) One min. power freq. withstand voltage (dry/wet)
-- for lines
-- for CB / Isolator
-- for other equipments

Remarks

1050kVp

680kV
520kV
610kV
630kV

460kV
460kV
530kV
460kV

(Line-ground)
(open terminals)

Substation Bird’s view

400kV Circuit Breaker

400kV Isolator

400kV Current Transformer

400kV CVT

400kV Surge Arrester

Shunt Reactor & NGR

400/220 kV Auto Transformer

400kV Bus Post Insulator

Wave Trap

Functions of substation equipments