Project No. E1219
NUMALIGARH REFINERY LIMITED
NRL REFINERY EXPANSION PROJECT
95 KTPA Hydrogen Generation Unit (HGU)
Assam (INDIA)
Project Document Title:
Electrical System Load Flow Study
Project Document Number:
E1219-HGU-EL-REP-0001
L&T Energy-Hydrocarbon Contract Reference Number:
MTG-LT/01 DATED 08 FEB. 2023
Owner
Client
MPMC
EPC Contractor
Licensor
02-May-24
Date
0
Rev.
: Numaligarh Refinery Limited
: Matheson Hydrogen India Pvt. Ltd.
: Technip Energies
: Larsen & Toubro Ltd.
: Topsoe A/S
Issued for Information
Description
AHC
SGP
ANS
Prepared By
Reviewed By
Approved By
Disclaimer:
This document contains confidential and/or proprietary information of LTHE and its affiliated companies. No part of this document, data,
or information, issued for the captioned project or purpose, shall be used for other than the purpose for which this has been provided or
disclosed to others or reproduced in any manner, except with the prior written permission of LTHE.
E1219-HGU-EL-REP-0001
Page 1 of 11
95 KTPA Hydrogen Generation Unit (HGU)
Numaligarh, Assam (INDIA)
ELECTRICAL SYSTEM LOAD FLOW STUDY
E1219-HGU-EL-REP-0001
Rev.0
02-May-24
Issue and Approval Record
Issued Category
Engineering
Approval Code
Procurement
Construction
[Code A or 1] - Approved
Consent to proceed
[Code B or 2] - Comments As Noted
Information
Enquiry
Construction
Work may proceed subject to incorporation of comments
[Code C or 3] - Rejected
Review
Purchase
Commissioning
Revise and Resubmit. Work shall not proceed
[Code D or 4] - Information Only
Approval
Void
As-Built
Does issue category require approval?
Yes
No
E1219-HGU-EL-REP-0001
Accepted for information only
Code:
NA
Date:
Approver:
Note: This approval does not relive the document ORIGINATOR
any of his obligations and responsibilities under this Contract.
Page 2 of 11
95 KTPA Hydrogen Generation Unit (HGU)
Numaligarh, Assam (INDIA)
ELECTRICAL SYSTEM LOAD FLOW STUDY
E1219-HGU-EL-REP-0001
Rev.0
02-May-24
Revision Record
Rev.
Date
Prepared
By
Reviewed
By
Approved
By
Revision Note / Description
0
25-April-24
AHC
SGP
ANS
Issued for Information
Note:

A ‘vertical line with revision triangle in the left hand margin plus revised text in Blue colour’ identifies changes in the
latest revision of document.

Revision description A, B, C..... etc. identifies document during development stage for review, approval and enquiry;
Revision description 0,1 ,2…..etc. identifies document if issued for information, or after approval if issued for purchase,
construction, commissioning etc.
R-X
E1219-HGU-EL-REP-0001
Page 3 of 11
95 KTPA Hydrogen Generation Unit (HGU)
Numaligarh, Assam (INDIA)
ELECTRICAL SYSTEM LOAD FLOW STUDY
E1219-HGU-EL-REP-0001
Rev.0
02-May-24
Contents
1.0
PURPOSE
5
2.0
ABBREVIATION
5
3.0
ETAP STUDY SCOPE
6
4.0
CODES, STANDARDS & REFERENCES
6
5.0
SOFTWARE
7
6.0
BASIS AND ASSUMPTIONS
7
7.0
ETAP LOAD FLOW ANALYSIS RESULT SUMMARY
10
8.0
CONCLUSION
10
9.0
ANNEXURES
11
E1219-HGU-EL-REP-0001
Page 4 of 11
95 KTPA Hydrogen Generation Unit (HGU)
Numaligarh, Assam (INDIA)
ELECTRICAL SYSTEM LOAD FLOW STUDY
E1219-HGU-EL-REP-0001
1.0
Rev.0
02-May-24
PURPOSE
The objective of carrying out the ETAP Load Flow Analysis for electrical system of Numaligarh Refinery
limited Numaligargh Refinery Expansion Project is to know and verify various electrical parameters
equipment /switchboard such as Loading, Voltage Profile and Power Factor etc. during different
operating conditions of plant.
2.0
ABBREVIATION
1C
: Single Core Cable
3C
: Three Core Cable
A
: Ampere
AC
: Alternating Current
BC
: Bus Coupler
C
: Cable
CT
: Current Transformer
DC
: Direct Current
DLL
: Design Margin Lump Load
DOL
: Direct On Line
EMLDB
: Emergency Main Lighting Distribution Board
EPMCC
: Emergency Power cum Motor Control Centre
ETAP
: Electrical Transient Analysis Program
FLC
: Full Load Current
FLL
: Future Growth Lump Load
NRL
: NUMALIGARH REFINERY LIMITED
HV
: High Voltage (1000V < V ≤ 33kV)
IC
: Incomer
IEC
: International Electrotechnical Commission
In
: Intermittent
JB
: Junction Box
kA
: Kilo Ampere
kV
: Kilo Volt
kVA
: Kilo Volt Ampere
kW
: Kilo Watt
LDB
: Lighting Distribution Board
LF
: Load Flow
LL
: Lump Load
LRC
: Locked Rotor Current
LV
: Low Voltage (< 1000V)
LTHE
: Larsen & Toubro Hydrocarbon Engineering
MCC
: Motor Control Centre
E1219-HGU-EL-REP-0001
Page 5 of 11
95 KTPA Hydrogen Generation Unit (HGU)
Numaligarh, Assam (INDIA)
ELECTRICAL SYSTEM LOAD FLOW STUDY
E1219-HGU-EL-REP-0001
3.0
MLDB
: Main Lighting Distribution Board
MPDB
: Main Power Distribution Board
MS
: Motor Starting
MVA
: Mega Volt Ampere
MW
: Mega Watt
OCTC
: Off Circuit Tap Changer
PCC
: Power Control Centre
PDB
: Power Distribution Board
PF
: Power Factor
S
: Standby
SB
: Switchboard
SC
: Short Circuit
SLD
: Single Line Diagram
TR
: Transformer
UPS
: Uninterruptible Power Supply
W
: Working
Rev.0
02-May-24
ETAP LOAD FLOW STUDY SCOPE
The Scope of Work for ETAP Load Flow Studies is limited to the following;

Start Point:


End Point:

4.0
Cable from 33kV Feeder of Upstream Substation No.10.-33kV Switchboard feeding 33kV
Switchboard SS12-GIS-ICOG-401& SS12-GIS-ICOG-402 (Upstream substation to NRL
Substation- SS12)
Equipment within NRL
CODES, STANDARDS & REFERENCES
Standard / Document No.
Description
E1219-HGU-EL-ELL-0001
Electrical Load List
E1219-HGU-EL-BOD-0001
Electrical Design Basis
E1219-HGU-EL-SLD-0001
Overall Key Single Line Diagram
E1219-HGU-EL-SLD-0003
Single Line Diagram for HV (6.6kV) Switchgear
E1219-HGU-EL-SLD-0004
Single Line Diagram for PMCC-01
E1219-HGU-EL-SLD-0005
Single Line Diagram for Emergency EPMCC-01
E1219-HGU-EL-SLD-0006
Single Line Diagram for MCC-01
E1219-HGU-EL-REP-0001
Page 6 of 11
95 KTPA Hydrogen Generation Unit (HGU)
Numaligarh, Assam (INDIA)
ELECTRICAL SYSTEM LOAD FLOW STUDY
E1219-HGU-EL-REP-0001
Standard / Document No.
E1219-HGU-EL-SLD-0007
E1219-HGU-EL-SLD-0008
5.0
02-May-24
Description
Single Line Diagram for ASB-01
Single Line Diagram for MLDB-01
E1219-HGU-EL-SLD-0009
Single Line Diagram for ELDB-01
E1219-HGU-EL-SCH-0001
HV Power & Control Cable Schedule
E1219-HGU-EL-SCH-0002
LV Power & Control Cable Schedule
SOFTWARE

6.0
Rev.0
Load Flow Analysis is carried out by using the ETAP Software of Version 20.6 (Operation
Technology, Inc, USA)
BASIS AND ASSUMPTIONS

All equipment is modelled in ETAP based on Design SLDs and Load List.
All the Motors have been Modelled for HV System & LV System. Rest of the Loads are modelled
as per the Load List with Static/Motor Characteristics for the respective Switchboards.

Following is Recommended for transformer in ETAP Load Flow Study Analysis;

Power & Distribution Transformer Tap : +2.5% (The tap is increased to limit the over-voltage
levels at 6.6kV switchboard & 415V PMCC

Lighting Transformer Tap


: +2.5% (The tap is decreased for to avoid
Overvoltage)
Transformer Impedance:
Sr. No.
1.a
1.b
2.a
E1219-HGU-EL-REP-0001
Transformer Tag
% Impedance
Make
Power Transformer
7.08 % (As per Test
Certificate)
M/s. Voltamp
9 % (As per Test
Certificate)
M/s. Voltamp
6.51 % (As per Test
Certificate)
M/s. Voltamp
SS12-TR-401
Power Transformer
SS12-TR-402
Distribution Transformer
SS12-TR-001
Page 7 of 11
95 KTPA Hydrogen Generation Unit (HGU)
Numaligarh, Assam (INDIA)
E1219-HGU-EL-REP-0001
Rev.0
Transformer Tag
% Impedance
Make
Distribution Transformer
SS12-TR-002
6.71 % (As per Test
Certificate)
M/s. Voltamp
Normal Lighting
Transformer
4% (As per Datasheet)
M/s. Automatic
Electric LTD
4 % (As per Datasheet)
M/s. Automatic
Electric LTD
Sr. No.
2.b
ELECTRICAL SYSTEM LOAD FLOW STUDY
3.a
SS12-TR-003 & 004
Emergency Lighting
Transformer
3.b

SS12-TR-005 & 006
Transformer Rating
02-May-24
: 33/6.9kV,8MVA, ONAN/ONAF
: 6.6/0.433kV,2MVA,ONAN
: 0.433KV/0.415,125kVA,ONAN
:0.433KV/0.415,40kVA,AN

DG Impedance
: No tolerance on DG impedance
Transient Reactance of generator (Xd') : 0.141 (As per Vendor Data; Make : M/S GOEL DG)
Sub-Transient Reactance of generator (Xd") :0.113 (As per Vendor Data; Make : M/S GOEL DG)


The following load contributions are considered in ETAP Study Analysis;

Continuous
: 100%

Intermittent
: 30%

Standby
: 10%
The following Lump Load(Future) contributions are modelled as per Load List data in ETAP Study
Analysis;
Sr. No.
SWB Tag No.
Voltage
% of Motor Load
% of Static Load
1
SS12-SGR-201A
6.6kV
90%
10%
2
SS12-SGR-201B
6.6kV
90%
10%
E1219-HGU-EL-REP-0001
Page 8 of 11
95 KTPA Hydrogen Generation Unit (HGU)
Numaligarh, Assam (INDIA)
ELECTRICAL SYSTEM LOAD FLOW STUDY
E1219-HGU-EL-REP-0001
Rev.0
02-May-24
Sr. No.
SWB Tag No.
Voltage
% of Motor Load
% of Static Load
3
SS12- PMCC-001A
415V
90%
10%
4
SS12- PMCC-001B
415V
10%
90%
5
SS12-EPMCC-001A
415V
80%
20%
6
SS12-EPMCC-001B
415V
80%
20%
7
SS12- MCC-001A
415V
90%
10%
8
SS12-MLDB-001A
415V
10%
90%
9
SS12-MLDB-001A
415V
10%
90%
10
SS12-ASB-001A
415V
20%
80%
11
SS12-ASB-001B
415V
20%
80%

Refer Annexure-3.0 for overall load summary.

The following data is considered as Source Input at 33kV Switchboard NRL-SS12-GIS-ICOG-401
& SS12-GIS-ICOG-402
Sr. No.
Voltage
SWB Tag No.
Max SC Current
Min SC Current
1
33kV
UPSTREAM S.S No.10
(Desc.: 33kV Switchboard)
33.5 KA
1915 MVAsc
X/R=16.5
6.0 kA
343 MVAsc
X/R=25
Remark
Values taken
from the Case
Study 17 Page
No.23

Max & Min SC current values are taken from available project data as informed by NRL.

Max SC Current Value is used for ETAP SC Study and Min SC Value is used for ETAP LF/MS
Studies.

Major Equipment Details are summarized in Annexure-1.0

Transformer ratings are found suufficient on peak load as per load list and future load growth.

Electrical Load List in Annexure 2.0

Power cable length is taken from Cable Schedule and parameters from Vendor Cable Data
(HV Cable From M/S POLYCAB & LV Cable From KEI ).
E1219-HGU-EL-REP-0001
Page 9 of 11
95 KTPA Hydrogen Generation Unit (HGU)
Numaligarh, Assam (INDIA)
ELECTRICAL SYSTEM LOAD FLOW STUDY
E1219-HGU-EL-REP-0001
Rev.0
02-May-24

Cable sizes and runs are as per approved cable sizing calculations and changes in cable sizes
required for maintaining sufficient voltage during motor starting are incorporated.

ETAP configurations considered for load flow are summarized in Annexure-3.0.

The following are allowable voltage variations as per Electrical Design Basis (Doc No. E1219-HGU-
EL-BOD-0001)

7.0
33kV
: ±10%

6.6kV
: ±6%

415V
: ±6%
The following is considered for carrying out ETAP Load Flow Study Analysis in each configuration;

Study Case Tag
: LF

Loading Category
: Normal

Transformer Impedance Tolerance
: Individual

Result Allowable Limits

Trafo Loading
: 100% (Critical)

Bus Over Voltage
: 110% (Critical)

Bus Under Voltage
: 90% (Critical)
ETAP LOAD FLOW ANALYSIS RESULT SUMMARY

8.0

ETAP Load Flow Analysis Results are summarized in Annexure-4.0 and the following are attached
for each configuration results;

ETAP Single Line Diagram

ETAP Output Report
CONCLUSION

Refer Annexure-3.0, ETAP Load Flow Study result gives the following conclusion;

Switchgears Bus Loadings are normal. No overloading observed.

Voltage range at each bus are in within limit. When the capacitors are Switched ON and
transformer tap is at normal position, there is overvoltage of approximately 1% at 6.6kV Bus
and 415V PMCC-001& Downstream Switchboards. Hence 8 MVA(33/6.9KV) Transformers
and 2 MVA(6.6/0.433Kv) Transformers are recommended to be at +2.5% tap & this tap is
used for all the system studies like SC & MS.

Transformers loading are found to be OK under all conditions.
E1219-HGU-EL-REP-0001
Page 10 of 11
95 KTPA Hydrogen Generation Unit (HGU)
Numaligarh, Assam (INDIA)
ELECTRICAL SYSTEM LOAD FLOW STUDY
E1219-HGU-EL-REP-0001
9.0
Rev.0
02-May-24
ANNEXURE
9.1
Annexure-1.0: Major Equipment Details
9.2
Annexure-2.0 : Electrical Load List
9.3
Annexure-3.0 : Overall Configuration Summary
9.4
Annexure-4.0 : ETAP Load Flow Results Summary
9.5
Annexure-5.1a: ETAP Load Flow SLD (Case-1)
9.6
Annexure-5.1b : ETAP Load Flow Report (Case-1)
9.7
Annexure-5.2a : ETAP Load Flow SLD (Case-2)
9.8
Annexure-5.2b : ETAP Load Flow Report (Case-2)
9.9
Annexure-5.3a : ETAP Load Flow SLD (Case-3)
9.10 Annexure-5.3b : ETAP Load Flow Report (Case-3)
9.11 Annexure-5.4a : ETAP Load Flow SLD (Case-4)
9.12 Annexure-5.4b : ETAP Load Flow Report (Case-4)
9.13 Annexure-5.5a : ETAP Load Flow SLD (Case-5)
9.14 Annexure-5.5b : ETAP Load Flow Report (Case-5)
9.15 Annexure-5.6a : ETAP Load Flow SLD (Case-6)
9.16 Annexure-5.6b : ETAP Load Flow Report (Case-6)
9.17 Annexure-5.7a : ETAP Load Flow SLD (Case-7)
9.18 Annexure-5.7b : ETAP Load Flow Report (Case-7)
9.19 Annexure-5.8a : ETAP Load Flow SLD (Case-8)
9.20 Annexure-5.8b : ETAP Load Flow Report (Case-8)
9.21 Annexure-5.9a : ETAP Load Flow SLD (Case-9)
9.22 Annexure-5.9b : ETAP Load Flow Report (Case-9)
9.23 Annexure-5.10a: ETAP Load Flow SLD (Case-10)
9.24 Annexure-5.10b: ETAP Load Flow SLD (Case-10)
9.25 Annexure-6 : Reference Vendor Document
E1219-HGU-EL-REP-0001
Page 11 of 11