CERT'D
NATIONAL GRID SA. الشركة الوطنية لنقل الكهرباء
A.M
A.M
APPR'D
A.M
A.M
CHK'D
M.Q
M.Q
AS PER COMMENTS
DESCRIPTION
FIRST ISSUE
BASE DESIGN
AC & DC LOAD CALCULATION
13.8kV SWITCHGEAR
REFURBISHMENT OF 110/33/13.8kV ARAFAT SUBSTATION
U.K
U.K
BY
13.05.2025
19.06.2025
DATE
REV.
00
01
REVISIONS
DESIGNED
BY:
DATE:
CHECKED
BY:-
DATE:-
OPRG. DEPT
BY
DATE:-
ENG'G. DEPT.
BY:-
DATE:-
CERTIFIED.
BY:-
DATE:- AS BUILT BY: DATE:
DRAWING TITLE INDEX PLANT DRAWING NO. SHEET NO. REV NO.
THIS DRAWING/DOCUMENT IS
NOT TO BE USED FOR
AC/DC Calculation
CONSTRUCTION OR FOR A NG2085 WE-1023761 1 of 8 01
ORDERING MATERIALS UNTIL FOR 13.8kV SWITCHGEAR
CERTIFIED AND DATED
MAKKAH SAUDI ARABIA CONTRACT NO: 4400021841 DCS NO.: WE-1023321
# CLASSIFICATION: Public
DC LOAD CALCULATIONS, 13.8kV SWITCHGEAR TYPE ALFA12
THE LOADS PER PANEL
SR NO. PANEL DESCRIPTION QTY.
CONTINUOUS MOMENTARY
1 TRANSFORMER INCOMER FEEDER PANEL 1 50.4 799
2 BUS SECTION PANEL 1 43.8 663.1
3 BUS VT/ EARTHING PANEL 1 30.3 821.2
4 STATCOM OUTGOING FEEDER PANEL 2 43.1 599.5
5 PLAIN OUTGOING FEEDER PANEL 24 36.1 599.5
THE TOTAL ESTIMATION CONTINUOUS DC LOADS FOR ALL PANELS (W)= 1077.1
THE TOTAL ESTIMATION MOMENTARY DC LOADS FOR ALL PANELS (W)= 17870.3
TOTAL ESTIMATION WITH SAFETY FACTOR 10% FOR CONTINUOUS DC LOADS FOR ALL PANELS (W)= 1184.81
TOTAL ESTIMATION WITH SAFETY FACTOR 10% FOR MOMENTARY DC LOADS FOR ALL PANELS (W)= 19657.33
General Notes:
1. Vaccum Circuit Breaker (VCB) characteristics are as follows:
a) Breaker Motor Spring charging time = 12s
b) Breaker closing coil operating time = 45ms (Approximately)
c) Breaker shunt trip coil operating time = 45ms (Approximately)
2. This calculation is only a tabulation of the DC loads of the ALFA12 Switchgear only. It is the responsibility of the Main Contractor to consider the
appropriate loads which he belives affects his DC system sizing calculation.
3.The calulation / tabulation is subjected to change based on comments by our client on the switchgear DC components.
4.Total estimation with safety factor 10% for continuous and momentory DC loads has been considered.
DC LOAD CALCULATION FOR ALL PANELS
NATIONAL GRID SA. 13.8kV SWITCHGEAR
01 AS PER COMMENTS A.M 2025 25 U.K M.Q الشركة الوطنية لنقل الكهرباء REFURBISHMENT OF 110/33/13.8kV ARAFAT SUBSTATION
00 FIRST ISSUE A.M 2025 20 U.K M.Q CONTRACT NO. DCS NO. PLANT DRAWING NO. SHEET REV.
REV. DESCRIPTION APPD. YEAR WEEK BY CHKD 4400021841 WE-1023321 NG2085 WE-1023761 2 of 8 01
# CLASSIFICATION: Public
AC LOAD CALCULATIONS, 13.8kV SWITCHGEAR TYPE ALFA12
BURDEN TOTAL LOADS
SR NO. COMPONENT DESCRIPTION QTY.
(W) CONTINUOUS MOMENTARY
1 HEATER LOW VOLTAGE 150 29 4350
2 HEATER CABLE COMPARTMENT 25 29 725
3 230VAC OUTLET FOR INCOMERS 1000 1 1000
4 LAMP 9 51 459
5 FAN CONTROLLER RELAY ZELIO 7 6 42
6 UPPER FAN 180 12 2160
7 RXM AUX. RELAY FOR SCHEME PURPOSE 1 26 13 13
THE TOTAL ESTIMATION CONTINUOUS DC LOADS FOR ALL PANELS (W)= 514
THE TOTAL ESTIMATION MOMENTARY DC LOADS FOR ALL PANELS (W)= 8248
Notes:
1. This calculation is only a tabulation of the AC loads of ALFA12 Switchgear. It is the responsibility of the Main Contractor to consider the appropriate loads which he belives
affects his AC system.
2.This calulation is subjected to change based on comments by our client on the switchgear AC components.
AC LOAD CALCULATION, FOR ALL PANELS
NATIONAL GRID SA. 13.8kV SWITCHGEAR
01 AS PER COMMENTS A.M 2025 25 U.K M.Q الشركة الوطنية لنقل الكهرباء REFURBISHMENT OF 110/33/13.8kV ARAFAT SUBSTATION
00 FIRST ISSUE A.M 2025 20 U.K M.Q CONTRACT NO. DCS NO. PLANT DRAWING NO. SHEET REV.
REV. DESCRIPTION APPD. YEAR WEEK BY CHKD 4400021841 WE-1023321 NG2085 WE-1023761 3 of 8 01
# CLASSIFICATION: Public
DC LOAD CALCULATIONS, 13.8kV SWITCHGEAR TYPE ALFA12
TRANSFORMER INCOMER PANELS
TOTAL LOADS
SR NO. COMPONENT DESCRIPTION BURDEN (W) QTY.
CONTINUOUS MOMENTARY
1 CB CHARGING MOTOR (MCH) (12SEC) 125 0 0
2 CB SHUNTCOIL (TC)(45mSEC) 200 2 400
3 CB CLOSING COIL ©(45mSEC) 200 0 0
4 E.S BLOCKING COIL 66 2 132
5 INDICATION LAMPS 2.6 8 10.4 10.4
6 CONTROL IED 18 1 18
7 RXSF1 DC CIRCUIT SUPERVISION 1.3 2 2.6 2.6
8 RXMB1 AUX. RELAY TEST/SERV MULTIP. 2 3 6
9 VDF10 TRIP CIRCUIT SUPERVISION 1.35 2 2.7
10 RXSF1 TRIP CIRCUIT SUPERVISION 1.3 2 2.6
11 ALPHA-TR RELAY FOR 50BF 127 2 254
12 RXM AUX. RELAY FOR SCHEME PURPOSE 1 5 5
13 RXMVB2 , ON /OFF Contact Multi Relay ABB 3.1 1 3.1
TOTAL LOAD ESTIMATED(Watts): 50.4 799
NOTE:
- DC CALCULATION SUBJECT TO BE CHANGED , BASED ON SEC APPROVAL FOR BASE DESIGN SUBMISSION.
DC LOAD CALCULATION, FOR TRANSFORMER INCOMER PANELS
NATIONAL GRID SA. 13.8kV SWITCHGEAR
01 AS PER COMMENTS A.M 2025 25 U.K M.Q الشركة الوطنية لنقل الكهرباء REFURBISHMENT OF 110/33/13.8kV ARAFAT SUBSTATION
00 FIRST ISSUE A.M 2025 20 U.K M.Q CONTRACT NO. DCS NO. PLANT DRAWING NO. SHEET REV.
REV. DESCRIPTION APPD. YEAR WEEK BY CHKD 4400021841 WE-1023321 NG2085 WE-1023761 4 of 8 01
# CLASSIFICATION: Public
DC LOAD CALCULATIONS, 13.8kV SWITCHGEAR TYPE ALFA12
BUS SECTION PANEL
TOTAL LOADS
SR NO. COMPONENT DESCRIPTION BURDEN (W) QTY.
CONTINUOUS MOMENTARY
1 CB CHARGING MOTOR (MCH) (12SEC) 125 0 0
2 CB SHUNTCOIL (TC)(45mSEC) 200 2 400
3 CB CLOSING COIL ©(45mSEC) 200 0 0
4 INDICATION LAMPS 2.6 7 9.1 9.1
5 CONTROL IED 18 1 18
6 RXSF1 DC CIRCUIT SUPERVISION 1.3 2 2.6
7 RXMB1 AUX. RELAY TEST/SERV MULTIP. 2 3 6
9 RXM AUX. RELAY FOR SCHEME PURPOSE 1 5 5
10 RXMVB2 , ON /OFF Contact Multi Relay ABB 3.1 1 3.1
11 ALPHA-TR RELAY FOR 50BF & 50/51 127 2 254
TOTAL LOAD ESTIMATED(Watts): 43.8 663.1
NOTE:
- DC CALCULATION SUBJECT TO BE CHANGED , BASED ON SEC APPROVAL FOR BASE DESIGN SUBMISSION.
DC LOAD CALCULATION, FOR BUS SECTION PANEL
NATIONAL GRID SA. 13.8kV SWITCHGEAR
01 AS PER COMMENTS A.M 2025 25 U.K M.Q الشركة الوطنية لنقل الكهرباء REFURBISHMENT OF 110/33/13.8kV ARAFAT SUBSTATION
00 FIRST ISSUE A.M 2025 20 U.K M.Q CONTRACT NO DCS NO. PLANT DRAWING NO. SHEET REV.
REV. DESCRIPTION APPD. YEAR WEEK BY CHKD 4400021841 WE-1023321 NG2085 WE-1023761 5 of 8 01
# CLASSIFICATION: Public
DC LOAD CALCULATIONS, 13.8kV SWITCHGEAR TYPE ALFA12
BUS VT/ BUS RISER EARTHING PANELS
TOTAL LOADS
SR NO. COMPONENT DESCRIPTION BURDEN (W) QTY.
CONTINUOUS MOMENTARY
1 E.S BLOCKING COIL 66 1 66
2 INDICATION LAMPS 2.6 2 2.6 5.2
3 RXSF1 DC CIRCUIT SUPERVISION 1.3 2 2.6
4 ES MULTIPLICATION RELAY 6RJ25 150 1 150
5 DIGITAL VOLTMETER TYPE MC330 4 1 4
6 RXM AUX. RELAY FOR SCHEME PURPOSE 1 5 5
7 HIGH IMPEDANCE PROTECTION RELAY 7 1 7
8 7840FD LOCK-OUT RELAY TRIPPING TC-1 150 1 150
9 7840FD LOCK-OUT RELAY TRIPPING TC-2 150 1 150
10 7840FD LOCK-OUT RELAY CLOSE BLOCK/CBF INITIATION 150 1 150
11 7840FD LOCK-OUT RELAY TRIPPING / BLOCKING 150 1 150
12 RXMVB2 ,IN/OUT RELAY OF 87B 3.1 1 3.1
13 CT SUPERVISION RELAY 2V68-S 6 1 6
TOTAL LOAD ESTIMATED(Watts): 30.3 821.2
NOTE:
- DC CALCULATION SUBJECT TO BE CHANGED , BASED ON SEC APPROVAL FOR BASE DESIGN SUBMISSION.
DC LOAD CALCULATION, FOR BUSVT/ BUS RISER EARTHING PANELS
NATIONAL GRID SA. 13.8kV SWITCHGEAR
01 AS PER COMMENTS A.M 2025 25 U.K M.Q الشركة الوطنية لنقل الكهرباء REFURBISHMENT OF 110/33/13.8kV ARAFAT SUBSTATION
00 FIRST ISSUE A.M 2025 20 U.K M.Q CONTRACT NO DCS NO. PLANT DRAWING NO. SHEET REV.
REV. DESCRIPTION APPD. YEAR WEEK BY CHKD 4400021841 WE-1023321 NG2085 WE-1023761 6 of 8 01
# CLASSIFICATION: Public
DC LOAD CALCULATIONS, 13.8kV SWITCHGEAR TYPE ALFA12
STATCOM OUTGOING FEEDER PANELS
TOTAL LOADS
SR NO. COMPONENT DESCRIPTION BURDEN (W) QTY.
CONTINUOUS MOMENTARY
1 CB CHARGING MOTOR (MCH) (12SEC) 125 0 0
2 CB SHUNTCOIL (TC)(45mSEC) 200 2 400
3 CB CLOSING COIL ©(45mSEC) 200 0 0
4 E.S BLOCKING COIL 66 1 66
5 HIGH IMPEDANCE PROTECTION RELAY 7SL86D 7 1 7
6 INDICATION LAMPS 2.6 5 6.5 6.5
7 CONTROL IED 18 1 18
8 RXSF1 DC CIRCUIT SUPERVISION 1.3 2 2.6
9 ALPHA-TR RELAY FOR 50BF 127 1 127
10 RXMB1 AUX. RELAY TEST/SERV MULTIP. 2 2 4
11 RXM AUX. RELAY FOR SCHEME PURPOSE 1 5 5
TOTAL LOAD ESTIMATED(Watts): 43.1 599.5
NOTE:
- DC CALCULATION SUBJECT TO BE CHANGED , BASED ON SEC APPROVAL FOR BASE DESIGN SUBMISSION.
DC LOAD CALCULATION, FOR METERED OUTGOING FEEDER PANEL
NATIONAL GRID SA. 13.8kV SWITCHGEAR
01 AS PER COMMENTS A.M 2025 25 U.K M.Q الشركة الوطنية لنقل الكهرباء REFURBISHMENT OF 110/33/13.8kV ARAFAT SUBSTATION
00 FIRST ISSUE A.M 2025 20 U.K M.Q CONTRACT NO DCS NO. PLANT DRAWING NO. SHEET REV.
REV. DESCRIPTION APPD. YEAR WEEK BY CHKD 4400021841 WE-1023321 NG2085 WE-1023761 7 of 8 01
# CLASSIFICATION: Public
DC LOAD CALCULATIONS, 13.8kV SWITCHGEAR TYPE ALFA12
PLAIN OUTGOING FEEDER PANELS
TOTAL LOADS
SR NO. COMPONENT DESCRIPTION BURDEN (W) QTY.
CONTINUOUS MOMENTARY
1 CB CHARGING MOTOR (MCH) (12SEC) 125 0 0
2 CB SHUNTCOIL (TC)(45mSEC) 200 2 400
3 CB CLOSING COIL ©(45mSEC) 200 0 0
4 E.S BLOCKING COIL 66 1 66
5 INDICATION LAMPS 2.6 5 6.5 6.5
6 CONTROL IED 18 1 18
7 RXSF1 DC CIRCUIT SUPERVISION 1.3 2 2.6
8 ALPHA-TR RELAY FOR 50BF 127 1 127
9 RXMB1 AUX. RELAY TEST/SERV MULTIP. 2 2 4
10 RXM AUX. RELAY FOR SCHEME PURPOSE 1 5 5
TOTAL LOAD ESTIMATED(Watts): 36.1 599.5
NOTE:
- DC CALCULATION SUBJECT TO BE CHANGED , BASED ON SEC APPROVAL FOR BASE DESIGN SUBMISSION.
DC LOAD CALCULATION, FOR PLAIN OUTGOING FEEDER PANELS
NATIONAL GRID SA. 13.8kV SWITCHGEAR
01 AS PER COMMENTS A.M 2025 25 U.K M.Q الشركة الوطنية لنقل الكهرباء REFURBISHMENT OF 110/33/13.8kV ARAFAT SUBSTATION
00 FIRST ISSUE A.M 2025 20 U.K M.Q CONTRACT NO DCS NO. PLANT DRAWING NO. SHEET REV.
REV. DESCRIPTION APPD. YEAR WEEK BY CHKD 4400021841 WE-1023321 NG2085 WE-1023761 8 of 8 01
# CLASSIFICATION: Public
