Chp Dc Sizing

SIMHAPURI ENERGY PRIVATE LIMITED ( SEPL) - HYDERABAD

2 X 135 MW THERMAL POWER PLANT PHASE 1

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3VYN591603-03

ABB LIMITED 220V DC CHP BATTERY BANK AND CHARGER SIZING CALCULATION

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We reserve all rights in this document and in the information therein. Reproduction, use or disclosure to third parties without express authority is strictly forbidden. ABB eBoP.

220V DC CHP BATTERY BANK AND CHARGER SIZING CALCULATION



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REVISION STATUS SHEET

REV. NO.

DATE

DESCRIPTION

R0

02.09.2009

FOR APPROVAL

R1

03.09.2009

FOR APPROVAL ( Revised as per Das-turco Comments dated 02.09.2009 vide

letter no. 372A)

R2 16.10.2009 Revise as per DCPL Comments vide dated15.10.2009



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1. ENGG. REFERENCE DOCUMENTS MPL ABB Technical Contract Document Design Basis Report ABB Doc. 3VYN931101-A R1 IEEE Std. 485 & IS :1651 Key One Line diagram- ABB Doc. 3VYN931101-R2 GPSPL DC load list as confirmed by Dasturco vide letter no.110A dated 13.07.2009. Dasturco drawing of Typical DC distribution -26298-00-00-ELE-0002- Rev.E

2. PROJECT DATA Voltage rating of 220V System : 220V (Nominal) : 242V ( Max. System Voltage) Voltage variation : + 10 % To - 15 % Fault Level : 25 kA at DCDB Level System : Un-grounded Ambient Temperature : 39.6 degree C Max. : 20.0 degree C Min.

3. SYSTEM DESCRIPTION

The Power plant comprises Two Generating units. For each unit, dedicated DC supply system is envisaged.

One CHP battery bank shall feed the DC supply to following DC loads of 2 X 135MW.

A. CHP MV Switch gear

B. CHP LV System ( Service Transformer + LV Board) C. DC Lighting

DC system for CHP comprises of One battery bank set and Two Float cum boost charger connected to DC distribution Board. in line with Dasturco Specification.

The batteries & charger shall be so designed that the maximum fault level on DCDB is limited to 25 KA.

The battery and battery charger combinations shall be such as to ensure continuity of D.C supply at load terminals without even momentary interruption.

Under normal condition CHP MV Switchgear shall receive the supply from corresponding Unit MV board and the TIE breaker in between both section shall be in OFF condition.

Complete blackout condition considered therefore all Motors Feeders on 6.6 KV MV switch-gear shall be tripped by sensing under voltage condition on respective bus.

Similarly, all 415V Breaker controlled Motors shall Trip on receiving command from under voltage relay of Bus PT panel of respective LV Switchgear and this will happen only when associated up-stream breaker tripping is completed.



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4. BATTERY SELECTION / SIZING CRITERIA

The batteries are considered as lead acid type with tubular positive plates (HDP II) in line with specification requirement.

Battery sizing and cell selection is based on IEEE: 485 & IS 1651. While estimating battery ca-pacities the following is considered:

A. Design Margin of 20 %

B. Ageing Factor of 1.25 %

C. End voltage of cell shall be not less than 1.85 Volt /cell during any time of the duty cy-cle.

D. Battery shall be rated for 10 hour discharge rate ( C10) as per manufacturer data. Bat-tery load cycle shall be 1 hour.

E. Temp Correction Factor, Cft = 1+R[(27-t) / 100], where R=0.43 for 10 hrs discharge as per table-2 of IS:1651, t = Electrolyte temp.=Min. site ambient temp (20 deg C) + in-cremental temp. of 10 deg C (as per Battery manufacturer recommendation ) = 30 deg C . Hence Cft= 0.98 . However, we have selected 1.0.

F. The enclosed battery sizing calculations is towards CHP DC system. The DC system sizing calculation for Creek System Battery bank shall be submitted as a separate document.

G. Continuous, momentary (0-1 min), continuous emergency (1-59 min) and Impulse (59-60 min) loads is calculated and duly considered in battery duty cycle curve.

H. The duty cycle imposed on the battery shall include the following. All momentary loads shall be treated as one minute load.

Continuous loads due to Energy Meters, Indication lights, Continuous energised coils, Control Panels, Relays.

Momentary loads due to switchgear operation, Valve operation.

Intermittent loads due to Motor starting requirements.

I. Tripping of Breaker, Starting of Lube oil pump are considered as 1st minute load of duty cycle .

J. Control supply to Switchboards/ Panels are considered for the entire load of 1 hour. Closing of Breaker is considered at last minute of duty cycle.

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5. CALCULATION

A. Battery Sizing Calculation

Input Parameters 1. Type of Battery = Lead Acid

2. Mfg. of Battery =

Any Approved make

3. Nominal System Voltage = 220 V

4. Maximum System Voltage = +10 %

5. Minimum System Voltage = -15 %

6. End Cell Voltage (ECV) = 1.85 V

7. Float Voltage = 2.15 V

8. Electrolyte Temperature = 30 C

9. Temperature Correction Factor = 1.0

10. Ageing Factor = 1.25

11. Design Factor = 1.1

12. No. of Duty Cycle = 3 Nos

DETERMINATION OF NUMBER OF CELLS

Nominal system voltage = 220 V Float voltage = 2.15 V Maximum allowable voltage 220 + 10 % = 242 V Minimum allowable system voltage 220 - 15 % = 187 V

Selected No. of Cells = 110 Nos Calculated Minimum System Voltages = (ECV x No. of Selected Cells)=1.85*110 =203.5V Calculated minimum system voltage is greater than the allowable minimum system voltage.

Hence, the determination of no. of cells as 110 Nos. is justified.

Amperehour calculation of Battery is calculated as per guide line of IEEE-485 / IS-1651 and is enclosed as Annexure-1.



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B. CHARGER SELECTION / SIZING CALCULATION

Annexure - 2

CONCLUSION

Type of battery Lead Acid type with Tubular Positive Plate ( HDP-II)

Application CHP Battery bank

10 Hour rating at 27 deg. Cent to 1.85Volt / cell

120AH

Quantity of Battery Bank One

No. of Cell 110

Rating of Charger 40A

Configuration FCBC

Quantity 2 X 100 % ( Total =2 Nos)

Enclosures :-

a. Annexure 1

b. Annexure 2

c. Annexure 3 (K Factor graph)

d. Annexure 4 (Load Cycle Graph )

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Chp Dc Sizing