RFE-1-BTA-ECE-IDO-001-REVB batteries sizing.pdf

PLANTA DE RESERVA FRÍA DE GENERACIÓN DE ETEN S.A

PROYECTO PROJECT

RESERVA FRÍA ETEN CONTRATISTA CONTRACTOR

TÍTULO TITLE

DC BATTERIES AND DISTRIBUTION BOARDS CALCULATION

Nº DE DOCUMENTO PROYECTO PROJECT DOCUMENT Nº

RFE-1-BTA-ECE-IDO-001

REV B EDITADO PARA ISSUED FOR

For Design FECHA DATE

15/01/2014

PRV

PRV

JSA

REALIZADO DONE BY

REVISADO CHECKED BY

APROBADO APPROVED BY

ESTE DOCUMENTO CONTIENE INFORMACIÓN PROPIETARIA Y NO PUEDE SER DUPLICADO, PROCESADO O CEDIDO A TERCEROS PARA UN USO DISTINTO AL DE ESTE PROYECTO Y EL OBJETO PARA EL QUE HA SIDO PREVISTO SIN LA AUTORIZACIÓN ESCRITA DE COBRA.

THIS DOCUMENT CONTAINS PROPIETARY INFORMATION AND CAN NOT BE DUPLICATED, PROCESSED OR DISCLOSED TO THIRD PARTIES FOR ANY USE OTHER THAN THIS PROJECT AND THE PURPOSE FOR WHICH IT IS INTENDED FOR WITHOUT THE WRITTEN CONSENT OF COBRA.

CALCULATION DC BATTERIES AND BOARDS Rev B

RFE-1-BTA-ECE-IDO-001 Pág/Page 2 de/of 15

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CONTROL DE MODIFICACIONES/CHANGE LOG

Revisión

Revision

Fecha

Date

Modificaciones

Modifications

A 13/12/2013

FIRST EDITION

B 15/01/2014 COBRA COMMENTS






ÍNDICE

1. OBJECT .............................................................................................................................. 4

2. REFERENCE DOCUMENTATION ...................................................................................... 5

3. GENERAL INFORMATION ................................................................................................. 6

3.1. SITE ........................................................................................................................... 6

3.1.1. Climate conditions .................................................................................... 6

4. APPLICABLE STANDARDS AND REGULATIONS ........................................................... 7

5. DC DISTRIBUTION SYSTEM DESIGN ............................................................................... 8

5.1. DC LOAD LIST ........................................................................................................... 8

5.2. CALCULATION OF NUMBER OF CELLS .................................................................. 8

5.3. BATTERY SIZING ...................................................................................................... 9

5.4. RECTIFIER SIZING .................................................................................................. 11

5.5. SHORT CIRCUIT CURRENT IN DC DISTRIBUTION BOARD ................................. 12

6. CONCLUSIONS ................................................................................................................ 14

7. ANNEXES ......................................................................................................................... 15






1. OBJECT

The purpose of the present document is to size the battery capacity and power rectifier changer

of DC Distribution Boards to supply to the ETÉN Power Generation Plant projected in Peru, with

an approximate net power of 230 MW.

The sizing of the Control Room UPS is also determined in Annex 2. There will be no DC power

consumption in the Control Room, so that the size of the battery shall be defined by the

manufacturer of the UPS system according to the size of the UPS itself.

This revision B is a preliminary calculation. Later on, the DC System supplier would develop a

more precise calculation with the actual battery cell data and the final load lists.






2. REFERENCE DOCUMENTATION

The following documentation shall be used as a reference in this document:

Specific reference documents:

RFE-1-BTA-EIP-IDO-001 : “DC System Specification”

Generic reference documents:

The documents quoted in the above references.






3. GENERAL INFORMATION

3.1. SITE

The plant shall be located a few kilometres from the municipal district of Reque in the province of

Chiclayo in the department of Lambayeque – Peru.

3.1.1. Climate conditions

The following climate conditions are adopted for the design:

Mean temperature ............................................................................................ 21.7 ºC

Ambient temperature range .............................................................. 14.6 ºC – 33.9 ºC

Relative humidity ............................................................................................... 73.2 %

Relative humidity range ...................................................................... 64.9 % - 81.0 %

Atmospheric pressure .............................................................................. 1013.9 mbar

Elevation ................................................................................................... +77.5 m asl

Location ..................................................................... Near to the sea (approx. 10 Km)

Maximum wind speed ..................................................................................... 95 km/h

Prevailing wind direction ................................................................... 179.3º from SSE

Average annual rainfall ................................................................................. 77.5 mm

Average monthly rainfall with “El Niño” phenomenon ..................................... 173 mm

Desert environment: Dirty Ambient .................................................................. 50µg/m3






4. APPLICABLE STANDARDS AND REGULATIONS

The battery capacity shall be calculated in accordance with the following codes and standards:

IEEE Std 485: Recommended Practice for Sizing Lead-Acid Batteries for Stationary

Applications.

IEEE Std 1184: Guide for Batteries for Uninterruptible Power Supply Systems






5. DC DISTRIBUTION SYSTEM DESIGN

5.1. DC LOAD LIST

The individual DC loads supplied by the battery during the duty cycle may be classified as

continuous or non-continuous.

Annex 1 of this document includes a table with a DC load list of the plant.

5.2. CALCULATION OF NUMBER OF CELLS

From IEEE std 1184 typical voltages of the lead batteries are:

Open Circuit (UN): ........................................................................................... 2,1 V/Cell

Float (UFLOAT) ...................................................................................... 2.15 to 2.4 V/Cell

Equalizing (UEQUAL) ............................................................................... 2.3 to 2.5 V/Cell

Cut Off (UC-O) .................................................................................... 1.67 to 2.10 V/Cell

The detailed calculation have to take the actual selected batteries data.

In the other hand, the limits for the DC system are:

Nominal (VN) ......................................................................................................... 125 V

Maximum (VMAX) ............................................................................... 125 +10% = 137 V

Minimum (VMIN) ............................................................................... 125 -15% = 106.3 V

Maximum voltage drop (ΔVDC) .......................................................... 5% 125 V = 6.25 V

Therefore the number of battery cells (NE) will be set from the following relationships, taking into

account the actual battery voltages:

a) Considering equalization voltage as the maximum system voltage

cellsV

V

V

VN

EQUAL

MAXE 57

4.2

137

b) Considering the battery Cut-Of voltage as the minimum system voltage

cellsV

VVN

OC

DCMINE 60

85.1

25.63.106

Or the end-of-discharge voltage, with a known number of cells is

VN

VVU

E

DCMINOC 975.1

57

25.63.106






The higher end of discharge voltage, the higher nominal battery capacity will be needed.

c) If the battery and charger are isolated from the loads during equalizing, the float voltage

shall be considered as the maximum battery voltage

cellsV

V

V

VN

FLOAT

MAXE 60

27.2

137

5.3. BATTERY SIZING

To determine the battery capacity, the duty cycle diagram of the batteries is used. The resultant

current in each operation mode is determined in annex 1.

The UPS loads are essentially static loads that maintain their power basically constant through

the whole discharge time.

For the DC loads it is assumed three peak consumptions due to the actuators (breakers,

contactors, and so).

The final result is as follows:

Time (min)

Duration of period

(minutes)

Total Load at 125 VDC

(A)

0 to 1 M1= 1 A1 = 540

1 to 14 M2= 13 A2= 450

14 to 15 M3 = 1 A3= 530

15 to 29 M4 = 14 A4= 450

29 to 30 M5 = 1 A5 = 530

And the duty cycle diagram is as follows.






Based on the duty cycle diagram, the battery capacity will be determined, using the standard

chart and the specific cell data.

The following is an example with a hypothetical cell battery with its own Kt factors.

Period Load Change in Load Duration of

Period Time to End of Section

Capacity at T Min Rate

Required Section Size

(Amp * Hrs)

(A) (A) (minutes) (minutes) Factor (Kt) Pos

Value Neg

Values

Section 1 - First Period Only - If A2 is greater than A1, go to Section 2

1 A1 = 540 A1-0 = +540 M1 = 1 T = M1 1 1.1 594

Sub. Total 594

Section 2 - First Two Period Only - If A3 is greater than A2, go to Section 3

1 A1 = A1-0 = 0,00 M1 = T = M1+M2 0

2 A2 = A2-A1 = 0,00 M2 = T = M2 0

Sub. Total 0,00

Section 3 - First Three Period Only - If A4 is greater than A3, go to Section 4

1 A1 = 540 A1-0 = +540 M1 = 1 T = M1+M2+M3 15 1.5 810

2 A2 = 450 A2-A1 = -90 M2 = 13 T = M2+M3 14 1.5 -135

3 A3 = 530 A3-A2 = +80 M3 = 1 T = M3 1 1.1 88

Sub. Total 898 -135

Total 763

Section 4 - First Four Period Only - If A5 is greater than A4, go to Section 5

1 A1 = A1-0 = 0,00 M1 = T = M1+M2+…+M4 0

2 A2 = A2-A1 = 0,00 M2 = T = M2+M3+M4 0

3 A3 = A3-A2 = 0,00 M3 = T = M3+M4 0






Period Load Change in Load Duration of

Period Time to End of Section

Capacity at T Min Rate

Required Section Size

(Amp * Hrs)

(A) (A) (minutes) (minutes) Factor (Kt) Pos

Value Neg

Values

4 A4 = A4-A3 = 0,00 M4 = T = M4 0

Sub. Total 0,00

Total 0,00

Section 5 - First Four Period Only - If A6 is greater than A5, go to Section 5

1 A1 = 540 A1-0 = +540 M1 = 1 T = M1+…+M5 30 1.75 945

2 A2 = 450 A2-A1 = -90 M2 = 13 T = M2+…+M5 29 1.75 -157.5

3 A3 = 530 A3-A2 = +80 M3 = 1 T = M3+M4+M5 16 1.5 120

4 A4 = 450 A4-A3 = -80 M4 = 14 T = M4+M5 15 1.5 -125

5 A5 = 530 A5-A4 = +80 M5 = 1 T = M5 1 1.1 88

Sub. Total 1153 -282.5

Total 870.5

The maximum section size, therefore, is 870.5 Ah

Once the battery capacity in Ah (Ampere by hour) is evaluated, the following correction factors

shall be applied:

Aging factor: A factor of 1,25 will be considered as aging factor, so that the load at the end of its useful life of the battery will be the expected load.

Design margin: A factor of 1,10 will be expected as reserve for a future expansion.

Temperature correction factor: The standard temperature for rating cell capacity is 25ºC. If the electrolyte has a different temperature, a temperature correction factor will be applied.

110,125,1)( AhAhC

AhAhC 1197110,125,15.870)(

To comply with the above criteria, the battery capacity required of each battery group will be

1197 Ah. The commercial battery capacity next larger than that is 1200 Ah.

5.4. RECTIFIER SIZING

The output rated power of the battery charger rectifier is determined taking into account that the

battery charger rectifier will supply the total rated power required for the direct current of the

plant.

The sizing of the rated power of the battery charger rectifier will be set so that in case of

unavailability of one of the rectifiers, the other equipment is able to supply the total power






demanded by the direct current services of the plant, and recharge the group of batteries in

maximum twelve (12) hours.

The rectifier size is determined as per IEEE Std 946 chapter 6.2.

To determine the output current of the battery charger rectifier, the efficiency of the batteries as a

result of internal losses should be taken into account. In addition, a minimum design margin of

20% should be considered for a future expansion.

2

1

1

1)(1,1

kkI

T

AhCcarIrec LC

AAh

AhcarIrec 65011540

12

12001.1

where:

Irec-char: Battery charger capacity (A).

C (Ah): Battery capacity required during the duty cycle (Ah).

T: Recharging time (h) to approximately 95% of capacity.

k1: Correction factor for temperature different from (25 ºC).

k2: Correction factor for altitude higher than 1.000 m.

ILC: Continuous load current supplied by the rectifier-charger (A).

1.1: is the constant that compensates for the battery losses.

To comply with the above criteria, the output power of each rectifier-battery charger will be

approximately of 100 kVA.

5.5. SHORT CIRCUIT CURRENT IN DC DISTRIBUTION BOARD

According to IEEE 946-1992, the short circuit current is the sum of the contribution of the battery,

battery charger rectifier contribution, and the contribution of the motors. Therefore, the short

circuit current DC Distribution Board will be:

MOTCARBATDCSC IIII

where:

ISC-DC: Short circuit current in the DC Distribution Board (A).

IBAT: Short circuit current contributed by the battery (A).

ICAR: Short circuit current contributed by the charger (A).






IMOT: Short circuit current contributed by the DC Motors (A).

To determine the short circuit current of the DC Distribution Board will be considered an

oversizing factor of 115%.






6. CONCLUSIONS

Based on the above results, the technical data of the DC Distribution Boards are as follows:

Input rated voltage: ............................................................................................ 480 V

Output rated voltage: ................................................................................... 125 V DC

Minimum battery voltage: ......................................................................... 112.5 V DC

Battery capacity: ............................................................................................ 1200 Ah

Recharging time: .................................................................. 12 Hours (95% charged)

Output rated power of rectifier-battery charger: ............................................ 100 kVA






7. ANNEXES

Annex 1: Plant DC and UPS Load List

Annex 2: Control Room UPS Load List

CALCULATION DC BATTERIES AND BOARDS

Rev. B

ANNEX 1

RFE-1-BTA-ECE-IDO-001 Page 1 of 2

ANNEX 1:

PLANT DC AND UPS LOAD LIST


Rev. B

ANNEX 1


KK

SD

ES

CR

IPTIO

NV

OLTA

GE

Un (

V)

PO

T. (k

W)

PO

T. (k

VA

)Irate

d (

A)

@ U

n

Irate

d (

A)

@

125 V

DC

0 -

1 m

in1 -

14 m

in14 -

15 m

in15-2

9 m

in29-3

0 m

in

GEN

ER

AL

UP

S(a

ssum

ing p

erf

om

ance in

vert

er

97%

)

1EG

A11C

F001-P

01

CA

UD

ALIM

ETR

O 1

RED

APO

RTE C

OM

BU

STIB

LE

220

0,3

00,3

51,6

02,4

72,4

72,4

72,4

72,4

72,4

7

1EG

A21C

F001-P

01

CA

UD

ALIM

ETR

O 2

RED

APO

RTE C

OM

BU

STIB

LE

220

0,3

00,3

51,6

02,4

72,4

72,4

72,4

72,4

72,4

7

1G

AF11C

F001-P

01

CA

UD

ALIM

ETR

O 1

RED

APO

RTE A

GU

A B

RU

TA

220

0,3

00,3

51,6

02,4

72,4

72,4

72,4

72,4

72,4

7

1G

AF21C

F001-P

01

CA

UD

ALIM

ETR

O 2

RED

APO

RTE A

GU

A B

RU

TA

220

0,3

00,3

51,6

02,4

72,4

72,4

72,4

72,4

72,4

7

PEN

DIE

NTE

PLC

SIS

TEM

A P

TA

220

1,5

01,7

68,0

212,3

712,3

712,3

712,3

712,3

712,3

7

PEN

DIE

NTE

PLC

SIS

TEM

A P

CI

220

1,0

01,1

85,3

58,2

58,2

58,2

58,2

58,2

58,2

5

PEN

DIE

NTE

PLC

SIS

TEM

A A

IRE

CO

MPR

IMID

O220

1,0

01,1

85,3

58,2

58,2

58,2

58,2

58,2

58,2

5

PEN

DIE

NTE

PLC

GR

UPO

DIE

SEL D

E

EM

ER

GEN

CIA

220

1,0

01,1

85,3

58,2

58,2

58,2

58,2

58,2

58,2

5

PEN

DIE

NTE

RA

CK

1 D

EL D

CS

220

3,0

03,5

316,0

424,7

424,7

424,7

424,7

424,7

424,7

4

PEN

DIE

NTE

RA

CK

2 D

EL D

CS

220

3,0

03,5

316,0

424,7

424,7

424,7

424,7

424,7

424,7

4

PEN

DIE

NTE

RA

CK

TELEC

OM

UN

ICA

CIO

NES

220

3,0

03,5

316,0

424,7

424,7

424,7

424,7

424,7

424,7

4

PEN

DIE

NTE

GEN

ER

AD

OR

AU

XIL

IAR

(S

AI)

220

4,0

04,7

121,3

932,9

932,9

932,9

932,9

932,9

932,9

9

1B

RB

11

TU

RB

INA

GA

S (

UPS

)127

4,0

04,7

137,0

532,9

932,9

932,9

932,9

932,9

932,9

9

PEN

DIE

NTE

SIS

TEM

A D

E M

ON

ITO

RIZ

AC

IÓN

DE E

MIS

ION

ES

(C

EM

S)

220

5,0

05,8

826,7

441,2

441,2

441,2

441,2

441,2

441,2

4

TO

TA

L L

OA

D O

F T

HE G

EN

ER

AL

UP

S27,7

032,5

9

DC

LO

AD

S (

DIR

EC

T F

RO

M B

AT

TER

IES

)

PEN

DIE

NTE

MA

ND

O -

SU

BES

TA

CIÓ

N125

5,0

05,0

040,0

040,0

060,0

040,0

060,0

040,0

060,0

0

PEN

DIE

NTE

MA

ND

O -

TR

AN

SFO

RM

AD

OR

1B

AT10

125

1,5

01,5

012,0

012,0

018,0

012,0

018,0

012,0

018,0

0

PEN

DIE

NTE

MA

ND

O -

TR

AN

SFO

RM

AD

OR

1B

BT51

125

1,5

01,5

012,0

012,0

018,0

012,0

018,0

012,0

018,0

0

PEN

DIE

NTE

MA

ND

O T

RA

NS

FO

RM

AD

OR

1B

FT51 (

MT/B

T)

125

0,2

00,2

01,6

01,6

01,6

01,6

01,6

01,6

01,6

0

PEN

DIE

NTE

MA

ND

O T

RA

NS

FO

RM

AD

OR

1B

FT53 (

MT/B

T)

125

0,2

00,2

01,6

01,6

01,6

01,6

01,6

01,6

01,6

0

PEN

DIE

NTE

MA

ND

O -

DIE

SEL

125

1,5

01,5

012,0

012,0

018,0

012,0

018,0

012,0

018,0

0

PEN

DIE

NTE

MA

ND

O -

INTER

RU

PTO

R

GEN

ER

AD

OR

125

1,0

01,0

08,0

08,0

012,0

08,0

08,0

08,0

08,0

0

PEN

DIE

NTE

MA

ND

O -

CC

M 1

BM

A52

125

3,0

03,0

024,0

024,0

036,0

024,0

036,0

024,0

036,0

0

PEN

DIE

NTE

MA

ND

O -

CA

BIN

A 1

BFA

51/5

3125

1,5

01,5

012,0

012,0

018,0

012,0

018,0

012,0

018,0

0

PEN

DIE

NTE

MA

ND

O C

AB

INA

1B

MA

52

125

1,5

01,5

012,0

012,0

018,0

012,0

018,0

012,0

018,0

0

PEN

DIE

NTE

MA

ND

O -

CA

BIN

A 1

BB

A51

(MED

IA T

EN

SIÓ

N)

125

1,5

01,5

012,0

012,0

018,0

012,0

018,0

012,0

018,0

0

TO

TA

L D

C L

OA

DS

18,4

0

TO

TA

L D

C L

OA

DS

+ G

EN

ER

AL

UP

S +

20%

SP

AR

E46,9

6537,1

8450,7

8532,3

8450,7

8532,3

8


Rev. B

ANNEX 2


ANNEX 2:

CONTROL ROOM UPS LOAD LIST


Rev. B

ANNEX 2


KKS DESCRIPTION VOLTAGE POT. (kW) POT. (kVA)

CONTROL ROOM UPS

PENDIENTECENTRALITA

CONTRAINCENDIOS220 0,50 0,59 2,67

PENDIENTE SISTEMA MEGAFONIA 220 1,50 1,76 8,02

PENDIENTE RACK TELECOMUNICACIONES 220 1,50 1,76 8,02

PENDIENTE SISTEMA CCTV 220 1,50 1,76 8,02

PENDIENTE ESTACIÓN DE OPERACIÓN 220 0,70 0,82 3,74

PENDIENTEESTACIÓN OPERACIÓN DE LA

TURBINA GAS127 0,50 0,59 4,63

PENDIENTEESTACIÓN DE OPERACIÓN

CEMS220 0,50 0,59 2,67

PENDIENTEESTACIÓN DE OPERACIÓN

GENERADOR AUXILIAR220 0,50 0,59 2,67

PENDIENTEESTACIÓN DE INGENIERÍA,

HISTÓRICOS Y ALARMAS220 0,50 0,59 2,67

PENDIENTE SERVIDOR DE HISTÓRICOS 220 0,50 0,59 2,67

PENDIENTESISTEMA SINCRONIZACIÓN

HORARIA (GPS)220 0,30 0,35 1,60

PENDIENTE IMPRESORA B/N OPERACIÓN 220 1,20 1,41 6,42

PENDIENTEIMPRESORA B/N REGISTRO

ALARMAS220 0,20 0,24 1,07

PENDIENTESWITCHES DE LA TURBINA

GAS127 0,60 0,71 5,56

TOTAL UPS LOADS 10,50 12,35

UPS OUTPUT DESIGN POWER (kVA) WITH 20% SPARE, AND PF =80% 15,75

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RFE-1-BTA-ECE-IDO-001-REVB batteries sizing.pdf