Battery Charger Calculation

BATTERY SIZING CALCULATION

PROJECT :- Typical 1X Fr6 GTG

CUSTOMER :- Tender

CONSULTANT :- NA

SITE :- NA

APPLICATION :- Gas Turbine TYPE OF BATTERY :- NI-CAD . DC NOMINAL VOLTAGE :- 125V DC FLOAT VOLTAGE :- 1.4V/Cell BOOST VOLTAGE :- 1.6V/Cell MIN AMBIENT TEMPERATURE:- 15 Deg C (for battery design)

However, Battery sizing considered for worst condition of 5 Deg C

MAXIMUM DC VOLTAGE :- 125 X 1.1 = 137.5V DC (+10%)

MINIMUM DC VOLTAGE :- 125 X 0.9 = 112.5V DC (-10%)

CELL END VOLTAGE :- 1.14V/Cell .

NUMBER OF CELLS :- Maximum DC voltage / Float voltage per cell

137.5 / 1.40 = 98 Nos.

The battery is sized for safe shutdown of gas turbine in the event of failure of AC supply.

TABLE – I

Sl No Tag No Loads in KW Description Load current Starting for 10 secs Load current Normal Load current Duration Remarks 01 88QE-1 7.5 DC Emergency Lube Oil Pump Motor 106.67 66.67 Amps Refer duty cycle Requirement for coasting down and cool down

02 88DS 7.5 DC Diesel Engine Starting Motor 106.67 66.67 Amps Refer duty cycle Requirement for start-up 03 88HR 0.56 DC Hydraulic Ratchet pump motor 8A 5 Amps Refer duty cycle - Requirement for cool down 04 Lighting 0.2 Lighting in GT Acc. Compartment 2A 2A Refer duty cycle Requirement for coasting down and cool down

05 TURBINE CONTROL PANEL (Mark-VI) 1.875 Turbine Control PANEL 15A 15 Amps Refer duty cycle 06 Emergency lighting 40 watts (12 numbers) 0.480 5 5 Refer duty cycle The load requirement occurs when AC lighting fails. 07 GT MCC (I/C ) 250 W GT MCC (for incomers ) 4 4 Refer duty cycle Considering 2A/ breaker & 2 breakers operating simultaneously. 08 GCP 1.25KW Generator Control Panel 10 10 Refer duty cycle - 09 GRP 1.25KW Generator Relay Panel 10 10 Refer duty cycle 10 AVR 1.25KW Automatic Voltage regulator 10 10 Refer duty cycle 11 Generator Emergency lighting 0.25KW 2 2 Refer duty cycle

DUTY CYCLE ON BATTERY IS AS FOLLOWS: 159.7A

1Min

127.7A

:

A1: FIRST 10 secs (Considering Starting :Loads sl.no 1, 4, 5,7,8,9,10,11,12 of Table –I Current ) starting currents are considered

159.67 Amps

A2: Next 14 Min , 50 secs : Loads sl.no 1,4 ,5,7,8,9,10,11,12 of Table –

I Normal currents are considered 119.67 Amps

A3: Next 1 Min : Loads sl no.1,3,4 ,5,7,8,9,10,11,12 of

table I are considered - Starting currents for 88HR 127.67 Amps L O A D C U R R E N T Load cycle continues

Section A3, A4 repeats sequentially for the next 105 Min (till the total duration of 2 hours) at the rate of 3min/cycle (1 min ON 2 min OFF and 35 such cycles occur in 105 Min.

DUTY CYCLE :

1) 159.7 Amps for 10 secs followed by

2) 119.7 Amps for 14 min 50 secs followed by 3) 127.7 Amps for 1 min followed by

4) 119.7 Amps for 2 min.

3 & 4 repeats for remaining duty cycle time. FACTORS TO BE CONSIDERED:

1) Aging factor = 20%

2) Design margin = 10%

3) Temp correction factor = For 5 deg C TABLE -1 Period Load ( In amps) Duration Performance factor (A/AH) as per vendor Datasheet-M/s HBL Temperature derating factor ( As per table- 01 of enclosed annexure-01) Combined performance factor I1= 181.7 10 sec. 2.56 _{0.81 2.06} I2= 141.7 14 min 50 sec. 1.08 0.85 0.92 I3 = 149.7 1 min. 2.06 0.81 _1.68 I4 = 141.7 2 min. 1.88 0.82 _1.53

TABLE -2 Step .No. Opening balance Load in Amps Duratio n Combined Performan ce Factor Ah Reqd. Ah Drain Ah Balan ce Ah to Add 1 0.00 159.7 10 sec 2.06 77.37 2.662 74.71 77.37 2 74.71 119.7 14 min 50 sec. 0.92 130.70 27.93 102.7 7 55.988 3 102.77 127.7 1 min. 1.68 76.14 2.13 100.6 4 0.00 4 100.64 119.7 2 min. 1.53 78.33 3.990 96.65 0.000 5 96.65 127.7 1 min. 1.68 76.14 2.13 94.52 0.000 6 94.52 119.7 2 min. 1.53 78.33 3.990 90.53 0.000 7 90.53 127.7 1 min. 1.68 76.14 2.13 88.40 0.000 8 88.40 119.7 2 min. 1.53 78.33 3.990 84.41 0.000 9 84.41 127.7 1 min. 1.68 76.14 2.13 82.29 0.000 10 82.29 119.7 2 min. 1.53 78.33 3.990 78.30 0.000 11 78.30 127.7 1 min. 1.68 76.14 2.13 76.17 0.000 12 76.17 119.7 2 min. 1.53 78.33 3.990 74.34 2.163 13 74.34 127.7 1 min. 1.68 76.14 2.13 74.01 1.797 14 74.01 119.7 2 min. 1.53 78.33 3.990 74.34 4.322 15 74.34 127.7 1 min. 1.68 76.14 2.13 74.01 1.797 16 74.01 119.7 2 min. 1.53 78.33 3.990 74.34 4.322 17 74.34 127.7 1 min. 1.68 76.14 2.13 74.01 1.797 18 74.01 119.7 2 min. 1.53 78.33 3.990 74.34 4.322 19 74.34 127.7 1 min. 1.68 76.14 2.13 74.01 1.797 20 74.01 119.7 2 min. 1.53 78.33 3.990 74.34 4.322 21 74.34 127.7 1 min. 1.68 76.14 2.13 74.01 1.797 22 74.01 119.7 2 min. 1.53 78.33 3.990 74.34 4.322 23 74.34 127.7 1 min. 1.68 76.14 2.13 74.01 1.797 24 74.01 119.7 2 min. 1.53 78.33 3.990 74.34 4.322 25 74.34 127.7 1 min. 1.68 76.14 2.13 74.01 1.797 26 74.01 119.7 2 min. 1.53 78.33 3.990 74.34 4.322 27 74.34 127.7 1 min. 1.68 76.14 2.13 74.01 1.797 28 74.01 119.7 2 min. 1.53 78.33 3.990 74.34 4.322 29 74.34 127.7 1 min. 1.68 76.14 2.13 74.01 1.797 30 74.01 119.7 2 min. 1.53 78.33 3.990 74.34 4.322 31 74.34 127.7 1 min. 1.68 76.14 2.13 74.01 1.797 32 74.01 119.7 2 min. 1.53 78.33 3.990 74.34 4.322

Design margin of 10% : 216.38 Ah

Aging factor of 20% : 259.65 Ah

Cell selected : KPM 300P

THE BATTERY SELECTED IS 98 KPM 300P

CHARGER SIZING CALCULATION

BATTERY CAPACITY : 125 VDC 300 AH Ni-Cd TRICKLE CHARGING CURRENT : 1.1 A

@ 2 MILLIAMPS PER AH

CONTINUOUS LOAD CURRENT : 45AMPS. (Loads no. 5 (15A), no 8 -(10A), no 9-(10A)

no 10- (10A)

(Float charge current= Continuous load + trickle current) THE CURRENT IN ON LINE : 46.1 FLOAT CHARGING

THE CURRENT REQUIREMENT : 0.2 X 300 FOR BOOST CHARGING : 60A Total charger rating : 105 A Charger rating selected : 110 Amps