CEA Guideliness

&EDERAL &UIDELIDES FOR 7&5/ 400/ 220/ 132 KU

SUB-STATIOD & SWITCH-YARD

OF THERmAL/ HYDRO POWER PROJECTS

CENTRAL ELECTRICITY AUTHORITY New Delhi -110066 June'2012

 

A.S. Bakshi Chairperson Central Electricity Authority

FOREWORD There has been a demand from the players in the power sector that CEA as an apex body in the sector, should finalize Standard Specification/ Design criteria/ Guidelines for power plant equipments to attract wider participation by equipment suppliers and encourage competition on one hand and reducing the time for pre-award activities, design & engineering and manufacturing on the other hand. With this objective in mind, CEA issued the 'Standard Technical Specification for Main Plant Package' in September 2008 and subsequently 'Standard Design Criteria/ Guidelines for Balance of Plant' in September 2010 for thennal power projects of2x500MW or above. To continue the standardization of equipments/ systems in power sector, the standardization of various electrical equipments in the sub-stations/ switchyard was also taken up. Switchyard/ Sub-station upto 400kV have generally been installed in the country. For higher unit sizes of 660/ 800MW, 765kV level switchyards/ sub-stations are also expected to be installed. Further, GIS and hybrid GIS are likely to be installed in near future. Accordingly, the document entitled "General Guidelines for 765/ 400/ 220/ 132kV Sub-stations and Switchyard for Thermal/ Hydro Power Stations" covering design criteria, parameters, other factors considered for selection/ design of various associated equipments/ systems and their constructional features is an attempt in this regard. Views of major players in the field of power have also been considered to reflect wider consensus in this area. I do hope that the utilities would find the document quite useful for effective planning and implementation and saving considerable time in project execution in the country.

New Delhi June 2012

M~ r

(A.S.BAKSHI)

 

General Guidelines for 765/400/220/132kV substations and switchyard of Thermal/ Hydro Power Projects

CONTENTS

Description

I Clause No.

Page No.

1.0

Introduction

1

2.0

System parameters

2 2

,_::3'-'.0'-----+-'S"'w""i"'tc:::hin=·g schemes

4.0_ _ _~j_L 7a?yso~u~t·~~~~~~~~---------~--~2'--~

I 4.1~_ _ _ ~A~rr~In~su~la~t~ed~Su~b~-~st=m7io=n~(~Al~S~)~---------+--~3~~ ,_1

4.2 4.3

I 5.0

f 5.1

i 5.2

I Gas insulated sub-station (GIS) Hybrid sub-station

5 5

Sub-station/ swit£!!l:'ard Equipment

6

I Bus bars (applicable for Al~S?&Sh"'y"i'bc..,ri:-;d-s-u'"b--s.,-tac-:ti:--o-n);:------+----:=6-

Switchyard hardware (applicable for AIS & hybrid sub7 station) 5.3 I Circuit Breaker (applicable for AIS) 8 !--'.::5'-::.4:---------!' Discounectors and earth switches (applicable for AIS) 11 :--:::-5.=:5_ _ _---ilc..,C:::Curr=e=nt_ transformer (applicable for AIS) 12 5.6 I Voltage transformer (applicable for AIS) 14 i--"5'-".7_ _ _----11 Surge arrestors (applicable for AIS & hybrid sub-station) 15 I 5.8 i Power transformer 17 I 5 .8.1 i Inter-counecting'Oa"'u"'to~tr=-an=s=fo:::rm=e=-r------------;-----;1:-;;7,--........; I 5.8.2 I Shunt and neutral reactors 19 5.8.3 I Monitoring systems and special equipments for ICT and 21 i reactor (optional) 22 ::.5:..::.8=..4'---------+·..:D=.e::.:s""i!l!lc review of power transformer 1

i

,_1

f--::5"'.9;-------~ 5.10

Wave trap

23

I Diesel Generator

24

Sub-station/ Switchyard control and monitoring system Sub-station automation system (SAS) Control , interlock, protection panels I Arr conditioned kiosk I Metering l Protections I Phase Monitoring Unit (PMU) Un-interrupted Power Supply Power Line Carrier Communication (PLCC) Power Line Carrier Communication (PLCC) for 400/ 220/ 132kV s stem I Power Line Carrier Communication (PLCC) for 765kV

24 24 25 26 27 28 32 34 34 34

L_.___ 6.0 6.1 6.1.1 6.1.2 6.1.3 6.1.4 6.1.5 6.1.6 6.2 6.2.1 6.2.2

37

l system ·-;-;----7""-;-----;c-;--7""---+---:-;-;:------i 6.3 Auxiliary power supply for sub-station/ switchyard 40 '-"-6.:::3:..:c.1_ _ _-'--'4=15V AC system 40 i

~ 6.3.1.1 6.3.1.2 6.3.2 6.3.2.1 6.3.2.2 6.3.2.3

General Guidelines for 765/400/220/132kV substations and switch_yard of Thermal/ H_ydro Power Projects

i L T transformers ' 415V switchgears DC s_ystem DC battery Battery charger DC distribution board (DCDB)

40 41 41 42 43 43

~ 7.0 i 8.0

Power & Control cables, la_ying and termination

44

Lighting

44

i 9.0

Grounding

45

10.0

Shielding

47

11.0

Fire Detection, Alarm & Protection S_ystem

47

12.0 12.1 12.2 12.3

Structural and Civil work Structures Civil Works Fencing

48 48 50 50

13.0

ComErehensive list of major International/ Indian Standards

50

Annexure A

Gas insulated sub-stations

1.0

General

51

2.0

S_ystem JJarameter~

51

3.0

Constructional reguirements

52

4.0

Circuit breaker

54

5.0

Disconnectors (isolators) & Earth switches

55

6.0

Current transformer

57

7.0

Voltage transformer

58

8.0

Outdoor bushin

58

9.0

Surge arrestors

58

10.0

Gas insulated bus duct

59

11.0

HV- Power cable connection (ifaJJJJ!icable)

59

12.0

HV-Power transformer connection (if applicable)

59

13.0

Gas system

59

ii

!

General Guidelines for 765/400/220/132kV substations and switchyard of Thermal/ Hydro Power Projects

14.0

Local control cubicles

60

15.0

GIS Earthin

60

'l~~------~~~~~~--~~---------------------~--~~~ 16.0

GIS foundation Grounding

61

17.~0-------+~~~o~n=rr=o~rm=·~g~sLy~st~em~------------~--------------~--~6~1--~

18.0

GIS building (if applicabl~--------------------+----"-6"-1---:

19.0

Comprehensive list of major International/ Indian standards

I Annexure B

i

61

Hybrid Gas insulated sub-stations

1.0

General

63

2.0

System parameters

63

3.0

Constructional requirement~----------

63

i-+--------1-= 4.0 Circuit-breaker 5.0

63

Disconnector/ earth switch

64

~-------------------+---~-

6.0 -------+-'=C:.::urr=eno:c.t:.:tr:::an=s'""fo"-rm=e.:c..r_____________________________-t----'6'-4'-----1 7.0~----+-Voltage transformer

8.0

64

Other eguipments/ systems

65

!--"9'-'.0'--------+-'C"o"'m"'p"-r.~hensive list of major International/ Indian stan,d,ar"'d"'s-+-+--.,_6,5

I Annexure C

Sketches of various Bus Bar Arrangement

67

~S~ch~e~d=u=le~---1~~SLy~~=em=Par~am~e~re=r~s-----------------------------+----7~1~--:

Schedule- 2

Safety clearances

73

~S~ch~e-d~u~le--~3~~S~a~lie-n~t_p_ar_am __e~te_r_s~fo~r~in~su-:l-m~o-r-str~in~g----------------~--~74 Schedule- 4 : Schedule - 5

Salient features of bus post insulator

76

Salient features of circuit breaker

77

t

Schedule- 6

Salient features of disconnector and earthing,_,s:.:_w,_,it~c"'h'--------+-----'8"-'0'-----1

Schedule -7

Salient features of current transformer

82

Schedule- 8

Salient features of voltage transformer

84

111

General Guidelines for 765/400/220/132kV substations and switchyard of Thermal/ Hydro Power Projects

Schedule- 9

Salient features of surge arrestor

86

SchedulelOA

Salient features of inter-connecting auto transformer 500MVA, 765/..J3! 400I..J3! 33kV, single-phase

88

Schedule10 B

Salient features of inter-connecting auto transformer - 500 or 315MVA, 400/220/ 33kV (constant ohmic impedance type)

92

SchedulellA

Salient features for 765/~3 kv (1 phase) shunt reactor and neutral reactor- Shunt reactor (1 phase) (765/..J3) kV

96

Schedule11 B

Salient features for 765/~3 kv (1 phase) shunt reactor and neutral reactor- Neutral reactor (765kV)

99

l Salient features for 400/~3 kv (1 phase) shunt reactor and

101

Schedule12A Schedule12B

! neutral reactor - Shunt reactor ( 1 phase) (400!..J3) kv l Salient features

for 400/~3 kv (1 phase) shunt reactor and 104 l neutral reactor - Neutt:al reactor (400kV_2_ _ _ _ _ _ _-+-~-----'·

~S~ch~e~d~u7le---1~3~~~~R~a~tin-gs-&~r-e-gu~rr~e-m_e_n-ts-of~P~L~C~C~re-rm~in-a~l~s---------+---l~07Schedule - 14

l

Salient

i

feature~'-'o" f'-"L: : T:_: trc- ano:so:.:fico: orm=e: : r:.: :s_ _ _ _ _ _ _---i---=-=-109

~~~-~-~~~~~~~~~~---------~-~-----'

Schedule- 15

Appendices

i International/ Indian Standards

111

------------------+-------;! ! Office Order of CEA for constitution of Committee

119

l List of Nominated Members of the Committee ·

121

i List of Participants in the 1'' Meeting

123

IV

General Guidelines for 765/400/220/132kV substations and switchyard of Thermal/ Hydro Power Projects

1.0

INTRODUCTION

i)

This document is an effort to consolidate maximum possible technical information/ data pertaining to switchyard for thermal/ hydro power projects and also sub-stations as per general prevailing practices for the use/ guidance. However, the site specific requirements need to be looked into by the owner/ developer of the systems.

ii)

The sub~stations/ switchyards constitute of transmissiOn system, which interconnects power transmission · circuits and transformation between networks of different voltages. It is required to pay careful attention in planning, designing and constructing the sub-stations/ switchyards, since its reliability directly affects the power supply availability. Sub-stations generally comprise of switchgear, power transformer, control, protection, monitoring and· automation equipment. The highest transmission system voltage in operation in the country is 800kV. Further, 1200kV level is also under consideration in near future.

iii)

The sub-stations are of three types based on its use, viz Substations attached to thermal/ hydro power stations (which is generally called as Switchyard), interconnecting sub-stations, step-down (EHVIHV, EHVIMV, HVIMV) substation. However, the sub-stations shall be of Air insulated sub-station (AIS), Gas insulated sub-stations (GIS) or Hybrid sub-stations. AIS is most commonly used so far; however, GIS/ hybrid substation may be adopted considering techno-economic viability. GIS is generally preferred, where availability of space and safety are major constraints, seismic prone areas, coastal areas and very heavily polluted areas etc. Hybrid sub-station (combination of AIS and GIS) are available upto 220kV level which requires comparatively less space than AIS. For renovation/ augmentation of existing AIS, hybrid option may be adopted considering space constraints and techno-economic viability.

iv)

This document describes salient parameters and technical features of equipment required for sub-stations and switchyard associated with thermal/ hydro generating stations. Specific details in respect of GIS and hybrid substation have been covered in Annexure-A and B.

1

General Guidelines for 765/400/220/132kV substations and switchyard of Thermal/ Hydro Power Projects

2.0

SYSTEMPARAMETERS The system parameters for 765kV, 400kV, 220kV, 132kV and 33kV are given in Schedule - 1

3.0

SWITCHING SCHEMES The selection of switching schemes depends on operational flexibility, system safety, reliability & availability, ability to facilitate the system control and cost. However, other types of switching schemes can be considered, if system demands. Following switching schemes shall generally be adopted at various voltage levels of switchyards/ sub-stations. The various types of switching schemes are shown in the Annexure -C." · Voltage level

(kV) 765

Switching schemes Air insulated substation! Switchyard

Breaker and a half i scheme

Gas insulated substation! Switchyard

i Breaker and a half i scheme i or

400

I Breaker and a half

I scheme

j Breaker and a half j s~;eme

I or ! Double main &

I Double bus scheme

iDouble main &

Double bus scheme

Double bus scheme

Double bus scheme or ; Single bus scheme with sectionalizer

I Double bus scheme

I transfer bus scheme

220

i Double bus scheme

i transfer bus scheme i or

I Double bus scheme i.

132

! Main and transfer bus

I ~~heme

I Double bus scheme I

I or ! Single bus scheme I with sectionalizer i

i Notes:

(1) In case of Breaker and a half scheme, the layout shall be either standard D or I type. (2) In case of GIS/ hybrid sub-station, the double bus bar scheme is most preferred [ economic solution with high reliability.

2

I·

I l j

General Guidelines for 765/400/220/132kV substations and switchyard of Thermal/ Hydro Power Projects

4.0

LAYOUT The actual layout shall depend upon the type of sub-station! switchyard (viz Air insulated sub-station (AIS), Gas insulated sub-station (GIS) or Hybrid substation). The area required would depend on voltage level, switching schemes, number of feeders of different voltage levels, no. of transformers, compensating equipments and possibility of future expansion.

In case of thermal power stations, the location of the switchyard shall be decided depending upon the wind profile to avoid additional pollution on account of water droplets from cooling towers.

4.1

Air insulated sub-station (AIS)

i)

Safety clearances: Safety clearances for different voltage levels and different configurations are given in Schedule - 2

ii)

Bay width and depth : For estimation purpose, approximate width and depth (excluding peripheral road arid fencing) of bays for various switching schemes at different voltage level are given below: Voltage level and switching scheme

Width""(-m)-+

I I) 765kV system:

Breaker & half scheme (I-type i!J

I

Dimension =---i

---'=-"

Depth (~~-~

3 20

52(2)

i 2) 400kV system : i) Breaker and a half scheme 1-type

27 170 7 27+2"'1-+""'27::-!·--:;1 20=(3)

. D-type

1

170(:1) 120

27+21+27 ii) Double main & transfer bus,_,s:::ch 00e:omoo:e,.__,_ ____ -+---"2"'-8.

~ 3) 220kV system :

i) Double main & transfer bus scheme

---+---=-=18:___l __7~5_ _,

I 4) 132kV system :

I

i

:

i) Double bus scheme ii) Main and Transfer

12 12

73.4 "'75 75

1-p~ase

In case of765kV, only 1-type is adopted, (2) Considenng 765kV I transformer/ fire wall, 54M may be considered. Further economization can be I done based on feeders/ transformers & reactor requirements during detailed I engineering, (3) D on one side of bus only, ------------~-i Type .

---+---_-HV----------+---~ Oil filled condenser/resin impregnated I ! paper ! Oil filled condenser/resin impregnated

-N

1i

l

- Neutral - LV

I

i 23b) ;

i f

i

L

'

.

Rated vol~e

- HV -N

--

- Neutral - LV

-

paper Solid porcelain/oil communicating Oil filled condenser/resin impregnated pa12er .

i

i

.

·-

kV kV kV kV

420 245 36 52 '

.

.

-

'

General Guidelines for 765/400/220/132kV substations and switchyard ofTherrnal/ Hydro Power Projects

I with stand voltage -~;----~--~-~HV~--------------~~k~V~rm~s~l6~3~0------------------------,: kVrms i 460 kVrms I 75 kVrms 195

- IV - Neutral - LV

~--~~---=~---------------+~~~~~------------------------1

I Corona extinction voltage - HV '-'-----+-ck;-:V:-::-rm--s--+ic::-50:-:Sc--------------

23g)

- IV - Neutral -LV

l~--~-----=~---------------

____________j

kVrms i 320 kVrms I --kVrms I ---

1

\ 23h)

.I

i < 0.004 (at 20°C)

l Tan delta

~~--------------~-----+------------------~--------:

!~2~3~i)~~~~Bu=s=ru~·ngC~T~:~~~-

· - 500 MVA (single phase) · f-----+~--=_'--'c""o'r'-'e-':1~="~="'-"L--f------j 1600/ 1, PS (HV/IV::-:/Nc::--eu-ctr-a-::-1--------!

i

i 600/ 1, 0.2 (HV)

- core 2

t------+------,-· - 315 MVA (singleLph=a=se::.L)__,_ _ -core 1 -core 2

\1000/1,0.2 _QY)_ _ __

! 1000/ 1, PS (HV/IV/Neutral) I 1000/ 1, 0.2 (HV)

! 600/1, 0.2

I Neutral CT

ll

! 400/ 1, PS

(IV)

------------· ___!

therm~

CoJtinuous rating of LV (tertikr) windinti" shall be capable o"f167MVA (minim\un) reactive and 5MVA (minimum)active loa~ing

(I)

I (2)

._j

1

cohtinuous thermal rating of LV (tetltiary) winJng shall be capable of 56MVA

! (minim\un) reactive and 2MVA (minimurr))active loa~ing

II (](minim\un) ) CoJtinuous thermal rating of LV (tertib) windmk shall be capable of 105MVA reactive and 5MVA (minimurr))active loa~ng i

t

'

j

Corltinuous thermal rating of LV (terti~ry) windink shall be capable of35MVA ! (minim\rm) reactive and 2MVA (minimun})active loa~ing 4 / ( )

I

(S)

On brincipal tap at rated MVA ofHV kd IV winbg at 75°C '

.

1 (

6 )

I(

7 )

l

wibout arcing horns To Be located in the neutral conductor Jonnecting ~ommon neutral point with earth for eatih fault protection !______-'-!-------------------------

95

General Guidelines for 765/400/220/132kV substations and switchyard of Thermal/ Hydro Power Projects

SCHEDULE -ll(A) [ See clause nos. 5.8.2 (xvii) (a) ]

SALIENT FEATURES FOR 765/--J3 KV (1 PHASE) SHUNT REACTOR

! 1)

I Rating

i 2)

! Nominal/ Rated voltage

765 N 3 kV

! 3)

l Maximum operating voltage

800 N 3 kV

! 4)

! Winding- connection (3 phase)

Star with neutral brought out

Ir - - -

~

[ j i

6) 7)

i

MVAR

' !

-

i Neutral earthing

I

80/110 (1 phase for 3 phase bank )

Earthed through neutral reactor

-

.

i Xo/ X, ratio . I I Magnetizing characteristics

0.9 to 1.0

.

Linear U]ZtO 1. 5 pu(I)

!

j

! 8)

.

ITolerance on current

---

I

0 to +5% for a 1 phase unit and ±1 among different phases of 3 phase bank

i 9)

I Permissible unbalan:::c:c::ec.::c:.:urr=e=nt=-+~-'-o/c.:..o-+=±:_:1_,(=arn=on::;g,_d=ifferent phases) _____J

j10)

I Ambient temperature

~

I 11)

r . I 12)

rur j

l

14)

c

! Temperature rise -top oil -winding

oc

·----f----o

----+--'--c

50 40 (thermometer method) ---------;j ._4"'5'-'(""re=.:s:::is::.::tan=cc::.e-=m,=e=th=o:.::d:L)---·----~

I Senn.~·:_:_ce~-------~--~-O~u=t=d.:..oo=r~--------~ Mineral oil

j Cooling medium

I Lightning (Full wave)

l

I

impulse withstand voltage (1.2/50 f.!-sec) - winding - neutral of reactorC2l

kVp kVp

1950 550

15) Switching impulse withstand ~---l ____:v_:::o:::lta?'g~e;'(::::25"-'0"'/2:::5:.::0:.::0-"f.l~-,s:::ec:.c)'--+--:-::-::-- -:-::~----------i - winding _ --,----+--"k~V.p_,__1:_:5:.::5::_0_ _ _· · - - - - - ---'----- neutral of reactor

_

96

General Guidelines for 765/400/220/132kV substations and switchyard of Thermal/ Hydro Power Projects

16)

[ One minute power frequency

r----+:---~~~·t=h~s~tan~d~v~o~h=ag~~~----+------~.!----------------------~ - winding - neutral of reactor

kVrms [ 230

i < 0.005 (at 20°C)

17)

[ Tan delta of windings

18)

I Partial dis?harge level (l.Spu)

pC

I Noise level

dB

19)

'

[ 100 (maximum)

-----·1

I < 80 at 800/ '13 kV and rated

I frequency

20)

I Reactor ~ushing ~~L---------~----~-------------

20a)

i Type

i Oil filled condenser bushing with

- HV - Neutral

__________________

[ test tap/resin impregl!ated paper i Oil filled condenser bushing with ·--+-------+[-"te:.=st.:.!.?.PI resin impregl!ated paper

i Rated vohag""e:____ _ _ _--1

20b)

- HV kV j 800 ~-7~~~~----~ - Neu.:::tra::::l_ _ _ _ _ j_ kV_,__-+I-"14_,..5:___~----­ i . - - -..--:::----;-------

! 20c)_ i _B.ated current - HV

----+---Ac-----i~-A-,-s_p_e.r ratiilg of transformer

- Neutral

i bushing and IEC

A

j

. As per rating of transformer·-----. bushing anEJEC

I --+-----+=-= \

! 20d)

----

Lightning (Full wave) impulse withstand vohage (1.2/50 f:!SeC} Ii - HV - Neutral

20e)

I Switching impulse withstand

~

.-·

f.

I I r-

2100 650

kVp kVp

1550

kVrms kVrms

970 275

I voltage (250/2500 f:!Sec) - HV

- Neutral

i 20f) i _ ,_ _

kVp kVp

One minute power frequency j with stand vohage - HV - Neutral

j

j .

-----1

97

General Guidelines for 765/400/2201132kV substations and switchyard of Thermal/ Hydro Power Projects

20g)

! Corona extinction voltage ! - HV

kVrms kVrms

- Neutral 20h) j Tan delta (at20° C) 20i)

i 508 i