cover sheeetTCE CONSULTING ENGINEERS
LIMITED30421008-3CL-00017-P0ASHEET i OF i125V DC STATION BATTERY
AND BATTERY CHARGERSIZING REPORTSAUDI ELECTRICITY COMPANYEASTERN
OPERATING AREADammam, Saudi ArabiaGENERATION EXPANSION OF RAFHA
POWER PLANT(CONTRACT NO : 30421008/00)DESIGN BASISFOR125V DC
STATION BATTERY & BATTERY CHARGER SIZINGDOCUMENT NO :
30421008-3CL-00017-P0ANOVEMBER 2004ENGINEERING CONSULTANTTCE
CONSULTING ENGINEERS LIMITED73/1, ST.MARK'S ROADBANGALORE
560001INDIACONTRACTOR:AL-TOUKHI COMPANY FOR INDUSTRY &
TRADINGP.O.BOX 497, RIYADH 11411, KINGDOM OF SAUDI
ARABIATEL.00966-1-4633660 : FAX.00966-1-4631150P0A
05.11.2004MPSRREV NO. DATEPREPARED BYCHECKED BYCLEARED BYAPPROVED
BY
&C&L&FSECTION :&A&RSHEET &P OF
&N
IndexCALCULATION DOCUMENTDOCUMENT NO.
30421008-3CL-00017-P0A.SIZING CALCULATION FOR STATION 125V DC
SYSTEMCONTENTSSECTIONDESCRIPTION1.0PURPOSE2.0STANDARDS &
REFERENCES3.0SIZING CRITERIA4.0BATTERY LOAD
CYCLE.5.0CONSIDERATIONS6.0DETERMINATION OF NO. OF
CELLS7.0CORRECTION FACTORS FOR BATTERY SIZING8.0DUTY CYCLE (LOAD
PROFILE)9.0BATTERY AND CHARGER SIZING CALCULATIONS.10.0DC LOAD
ESTIMATION11.0CONCLUSION
&CGENERATION EXPANSION OF RAFHA POWER PLANT(CONTRACT NO :
30421008/00)&L&FSECTION :&A&RSHEET &P OF
&N
WriteupCALCULATION DOCUMENTDOCUMENT NO.
30421008-3CL-00017-P0A1.0PURPOSE:The purpose of this calculation is
to determine the sizes of the 125V DC battery and battery charger
for the Station DC System of GTG#1 and GTG#2 of RAFHA Central Power
Station.2.0STANDARDS & REFERENCES2.1SCECO Engineering Standard
SES-P-103.02 - Revision-3 : Storage Battery selection and capacity
determination.2.2SCECO Engineering Standard SES-P-103.03 -
Revision-3 : Battery Charger sizing.2.3IEEE-485 - IEEE Recommended
Practice for Sizing of Large Lead Acid Storage Batteries for
Generating stations and Sub Stations.2.4Key One Line Diagram for
Rafha Plant Drawing No:KA-6667481,Rev-P0D SHEET 1 OF 13.0SIZING
CRITERIA3.1The battery has been sized to meet the Station DC loads,
namely the switchgear control supplies and the Lighting load in the
event of black out, for a period twelve (12) hours.The DC Loads
pertaining to Gas turbine and Generator Auxiliaries are not
considered as part of these calculation.Since these loads would be
catered by unit DC system.3.2The Type of battery selected is Vented
Type Lead Acid Battery as per cl no 3.03-26(a), page 42 of 331 of
PTS-10243.3The End cell voltage is considered as 1.75V as per
SES-P-103.02.3.4Design marigin factor of 1.1 has been considered as
per cl.no.4.4.2 of SES-P-103.023.5Ageing factor of 1.25 has been
considered as per cl.no.4.4.3 of SES-P-103.023.6The Battery room
temperature is considered as 25 deg C and the temperature
correction factor of 1.19 based on inside room temperature of 10
Deg C in case of power failure is considered as per cl.no 2.2 of
SES-P-103.02. Page 17 of 353.7Capacity correction factors and
Temperature correction factors are based on SCECO
engineeringstandard SES-P-103.02.
&CGENERATION EXPANSION OF RAFHA POWER PLANT(CONTRACT NO :
30421008/00)&L&FSECTION :&A&RSHEET &P OF
&N
Notes for SizingCALCULATION DOCUMENTDOCUMENT NO.
30421008-3CL-00017-P0A.4.0BATTERY LOAD CYCLE4.0.1Prior to blackout
the following plant configurations are considered:As a worst
case,Incomer & Feeder Breakers of 33 kV switchgear,4.16kV
Switchgear, Unit LV Switchgear and Station LV Switchgear are
considered as closed. On loss of power in the plant, all the above
referred circuit breakers will trip.This load is considered as 1
minute load at starting of duty cycle.4.0.2On return of normal
power supply, simultaneous closing of one incomer & one
outgoing feeder, tripping of one breaker if fault persists,
starting of one spring charging motor and running of one spring
charging motor are considered as per c.l.no.2.3(b) of SES-P-103.02.
page no 18 of 35. This load is considered as 1 minute load prior to
end of duty cycle.4.0.3Starting current of spring charging motor is
taken as 5 times the normal current as per cl.no 2.4
SES-P-103.02.4.0.4Continuous loads corresponding to remote
control/annunciation panels, OLTC panels of Generator Transformer,
Station Transformers,indications on switchgear for a period of 12
hours.4.0.5DC Emergency lighting load for 3 hours which will be
switched on within 3 hours of power failure in accordance with
cl.no. 2.6 of SES-P-103.035.0CONSIDERATIONS5.1.1The following types
of indication lamps and transducers have been condsidered for the
MV breakers(a)Indication Lamps for(b)Transducers fori) Breaker
-ONi) Voltage(V) Transducerii) R phase -ONii) Ammeter(A)
Transduceriii)Y phase -ONiii) Watt (W) Transduceriv) B phase -ONiv)
Power Factor(PF) Transducerv) Trip circuit healthy -ONv) VAR
Transducer5.1.2The following type of Indication Lamps &
Annunciations have been condsidered for Remote control/Annunciation
Panel.(a)Indication Lamps for(b)Annunciations fori) Breaker -ONi)
Transformer Winding Temperature highii) R phase -ONii) Transformer
Winding Temperature very high.iii)Y phase -ONiii)Transformer oil
temperarue highiv) B phase -ONiv) Transformer oil temperature very
highv) Trip circuit healthy -ONv) Buchholz relay for transformer
and OLTCvi) Pressure relief valvevii) DC supply supervision
relayviii) Trip circuit supervision relayix) O/C & E/F
protectionx) REF protectionxi) Differential protectionxii) Overall
Differential protectionxiii) Lockout relayxiv) Under Voltage
Relayxv) AC trip coil healthyxvi) Motor Protection Relay
&CGENERATION EXPANSION OF RAFHA POWER PLANT(CONTRACT NO :
30421008/00)&L&FSECTION :&A&RSHEET &P OF
&N
Cell NumberCALCULATION DOCUMENTDOCUMENT
NO.30421008-3CL-00017-P0A6.0DETERMINATION OF NUMBER OF CELLSNominal
cell voltage:2voltsNominal battery voltage:125voltsas per cl.no 2.0
of SES-P-103.02Float voltage:2.2voltsas per cl.no 2.0 of
SES-P-103.02End cell voltage:1.75voltsas per cl.no 4.1.2(d) of
SES-P-103.02Minimum permitted Voltage:101.5voltsas per cl.no 2.0 of
SES-P-103.02Maximum Permitted Voltage:136.3voltsas per cl.no 2.0 of
SES-P-103.02Number of cells required considering the minimum system
voltage and end cell voltage =101.5/1.75=58.00..(i)Number of cells
required considering the maximum system voltage and float voltage
=136.3/2.2=61.95..(ii)Number of cells chosen is lower of the above
2 values =58.00Maximum system voltage considering 58cells and float
voltage of 2.2 volts is 58 * 2.2=127.6volts
