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D1204016 060604-P-004

sheet 1 of 3

B

A

REV DATE DESCRIPTION PREPARED REVIEWED

RKK DC

03.10.07REVISED AS PER CUSTOMER

COMMENTS DTD 17.09.07RKK DC

27.08.07 ISSUED FOR APPROVAL

RESPONSIBILIT IES OR LIABILITIES UNDER PURCHASE ORDER.

SIGNED BY : DATE :

DAELIM'S PERMISSION TO PROCEED OR REVIEW TAKEN ON

VENDOR PRINTS SHALL NOT RELIEVED VENDOR FROM ITS

RFC - RETURN FOR CORRECTION

NA - NOT APPLICABLE

A - APPROVED WITHOUT COMMENT

AAN - APPROVED AS NOTED

DOCUMENT TITLE :

DAELIM INDUSTRIAL CO.,LTD

JOB NO. 060604

CT/PT DETAILS AND CALCULATIONS

FOR 440V SWITCHGEAR & MCC

P/O NO. PO-060604-0200-304-001-A01 V/P NO.VP-PO-060604-0200-304-001-A01

-105-MCC-101-009-B

VENDOR AL-AHLEIA SWITCHGEAR CO.,KUWAIT ITEM NO. 105-MCC-101A,B

OWNER Kuwait Oil Company (K.S.C) INQ. NO. 060604-0200-304-01

JOB TITLE Replacement of 9 Crude Oil Filling Lines Project DIC JOB NO. 060604

BJ

APPROVED

BJ

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D1204016 CT/PT DETAILS AND CALCULATION(PROJECT: REPLACEMENT OF 9 CRUDE FILLING LINES IN STATE OF KUWAIT)

060604-P-004

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440V SWITCHGEAR/MCC 105-MCC-101A,B

1. CURRENT TRANSFORMERS:

a. Metering:

Incomers & Bus Tie:

Connected equipments Burden (VA)

Ammeter 1.5

Connecting wires 0.1

1.6

Characteristics of CT : 1000/1A,CL-1,15VA

b. Over current and E/F:

Incomers:

Connected equipment is P127 of Areva

Recommended CT requirements by relay manufacturer: 5 VA, Class 5P10

Characteristics of CT: 1000/1A, CL-5P10, 15VA

Bus Tie:

Connected equipment is P123 of ArevaRecommended CT requirements by relay manufacturer: 5 VA, Class 5P10

Characteristics of CT: 1000/1A, CL-5P10, 15VA

c. Restricted E/F:

Connected equipment is P120 of Areva

Transformer Secondary Voltage (V) 457 V

KVA rating of Transformer 630 KVA

Impedance of Transformer (Z) 6 %

CT Resistance (RCT) 6 Ω

Length of 2.5sq.mm cable between Transformer Neutral CT and relay. (assumed) 20 mtr

Resistance of 2.5 sq.mm cable (assumed) 7.41 Ω /km

Lead Resistance (2R) 20*7.41*2/1000 = 0.2964 Ω

CT Ratio (CTR) 1000 /1A

Relay setting range (IR) 0.1

0.4

Fault current in CT secondary (IF) = [KVA*1000 / (√3*V*Z)]/CTR 13.3 A

Stability Voltage (VS) = K*IF*(RCT+2R) 83.5 V

K=1 for REF application

Knee point voltage of CT (VK) = 2*VS 167.1 V

VK/VS=2

Characteristics of CT: 1000/1A, CL-X, Vk ≥ 170V, Rct ≤ 6Ω

Stabilizing Resistor minimum (RST-max) = VS / Relay setting min. 835.3 Ω

Stabilizing Resistor maximum (RST-min) = VS / Relay setting max. 208.8 Ω

Max unsaturated voltage (VF) = IF*(RCT+2R+RST-max) 11164.0 V

2*√[2*VK*(VF-VK)] 3834.0 V

Since Vp is greater 3000V peak, non-linear resistor (Metrosils) will be used.

Stabilizing Resistor = 0 to 1500Ω

Characteristics of CT: 1000/1A, CL-5P10, 15VA

Peak voltage developed by CT under

internal fault condition (VP) =

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D1204016 CT/PT DETAILS AND CALCULATION(PROJECT: REPLACEMENT OF 9 CRUDE FILLING LINES IN STATE OF KUWAIT)

060604-P-004

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2. VOLTAGE TRANSFORMERS:

Connected equipments Burden (VA)

P127 0.25

Voltmeter 4.5

Connecting wires 0.1

4.85

Characteristics of PT: 440/√3/110/√3, CL-1/3P, 200VA

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