1
INTRODUCTION
1.1
ARCHITECTURAL PRINCIPLE OF THE SITE
The project aims to construct 4 Data center buildings (A, B, C, and D).
The buildings will be constructed in different phases.
The infrastructures common to the data center buildings are:

the 225kV/21kV substation,
The total load is 400 MW (with 264 MW of IT load).
1.2
APPENDICES
To these written documents are annexed:

Calculation notes and datasheets,

Diagrams

Layout plans,
This document must be read in conjunction with all other contractual documents.
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2
ELECTRICAL BASIC DATA
2.1
CALCULATION BASES
2.1.1
ELECTRICAL CURRENT CHARACTERISTICS

Medium voltage (MV)

Voltage 21 kV

Frequency 50 Hz

Source RTE (Internal substation 225 kV HV)
2.2
GENERAL
The project will be supplied from a 225 kV network, for a final overall power of 400 MW.
A source substation is planned to supply the site. It shall consist of 4 transformers, 225 KV/21 KV 120 MVA (in normal
operation), and 2 similar transformers (in emergency operation) feeding through MV cables in UPVC ducts AIS (Air
Insulated Switchgear) 21 KV MV switchgears located in technical rooms. Fire rated barriers (4-hour fire resistant) shall
be located between the transformers.
2.3
STANDARDS AND REGULATIONS
2.3.1
HIGH VOLTAGE ELECTRICITY
Electrical systems must be developed in accordance with the:

Digital Property Design Guides (DPM)

Harmonised European wiring standards IEC 60364

Low Voltage Directive 2014/35/UEC 03: Schematics and symbols,

C 04-200: Conductor marking,

C 13-100: Delivery station installations,

C 13-200: High voltage electrical installation.

C 14-100: Low voltage electrical installations,

C 15-100: Low voltage electrical installations. Rules,

NFC 17-100 to 17-102: Lightning protection

C 18-510 and C 18-513: Safety requirements,

C 20-010: Classification of degrees of protection provided by enclosures,

C 63-421: Low-voltage switchgear and control gear,

C 63-850 and EN 61-131-1: Programmable controllers. Low-voltage industrial switchgear,

C 91-100: Protection of radio and television broadcasting against interference from industrial sources industrial
origin
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
IEC 61000-3-2 which defines limits for harmonic current emission from equipment consuming less than 16 A
per phase

IEC 61000-2-2 which defines the compatibility levels of harmonic voltages on public low voltage networks

The Unified Technical Documents (DTU) published by the Centre Scientifique et Technique du Bâtiment (CSTB)

Legislative texts, decrees, ministerial orders, circulars and regulations in force, published by the Direction des
Journaux Officiels:

The Labour Code

Construction Products Regulation (CPR) according to EN 50575 Safety of machinery - IEC 60204-1:2016 FM

Global Requirements

EN 1838 - Emergency lighting applications

EN 12464-1 and EN 12464-2

French standards approved or registered, published by the Association Française de Normalisation (AFNOR)
for electricity.

NF EN 60439.1: Construction of low voltage switchboards

Recommendations of RTE, the Electricity Network Operator and concessionaires,
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3
HV-MV SPECIAL REQUIREMENTS
3.1
DESCRIPTION OF THE FACILITIES

Introduction
The total power supply to the site from RTE will be estimated at 400 MW.
225kV/20kV Substation
The planned source substation will be of the open type or AIS (Air Insulated Switchgear).
The types of cubicles and services that will be provided are (not exhaustive):

2-line arrivals, for the connection of main and emergency power supplies from the public electricity transmission
network.

1 busbar

6 primary power transformer connections

6 x 120 MVA HV/MV transformers (space allowance for 2 spare transformers, however the incoming supply of
these 2 transformers shall be considered at this stage)

MV switchgears inside the primary substation

Lightning arrestors if required

Control systems

The regulation systems

Communication systems with RTE.
3.2
SCOPE OF WORKS
The work includes design, supply, handling, installation, connection, testing and commissioning:

Voltage regulations are taken over by the MV cubicles where the dedicated VTs and homopolar generators will
be located

Supply and installation of the 21 kV cable sheaths from the HV/MV transformers to the MV Rooms.

Design of the earthing network,

MV connections between the different MV rooms inside the primary substation,

6x120 MVA 225 kV/21 kV Transformers

The interlocks for the proper functioning of the system.

All equipment and systems that allow complete installation in accordance with the rules of the art and functional.

Complementary trenches and conduits for the passage of cables.
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3.3
HV/MV ELECTRICAL DISTRIBUTION PRINCIPLE
3.3.1
POWER SUPPLY FOR 120MVA TRANSFORMERS
The phasing of the project is shown in the figure below:
Phasing of the project
The 2 HV cables from the Transmission Network that arrive at the site, in the substation feed 6 225/21kV 120 MVA
transformers that will step down the input voltage of the site from HV (225kV) to MV (21kV), ready for distribution. The
Figures below show the schematic layout of the 6 HV/MV transformers on the site and the AIS substation layout.
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HV/MV transformers of the substation
Substation layout
3.3.2
PRIMARY MV DISTRIBUTION
The primary distribution in this document constitutes all the links that connect the 120 MVA transformers and the main
primary distribution boards of the site.
Thus the 6 MV supplies (21kV) lowered at the output of the transformers are routed to the main MV distribution premises
of the site. Each of these main MV distribution rooms on the site will contain 2 MV switchboards. These main MV
switchboards in each MV room will be interconnected to allow for better resilience.
MV rooms will be interconnected together as well to mitigate any fault scenario which may occur during the phasing
installation:
Interconnection between MV rooms (in green)
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3.3.3
LOCATION OF MV ROOMS

Primary MV rooms
The primary MV rooms are located within the 225 kV / 21 kV source station.
Primary distribution room arrangement
3.4
SPECIFICATION OF HIGH VOLTAGE EQUIPMENT
3.4.1
PRIMARY SWITCHGEARS 21KV - 3150A
These are the primary distribution switchgears fed directly from the 120MVA transformers. Two coupled panels are
provided inside each MV room.
3.4.2
TECHNICAL DESCRIPTIONS OF 21KV PRIMARY SWITCHGEARS
The switchgears of the project are air insulated indoor-mounted metal enclosed type.

General specifications
The general electrical specifications of these cubes are summarized in the following table:
Rated voltage
Rated power frequency withstand voltage at altitude less
than 1000m
Ur
kV
24
Ud
kV
50
BIL at altitude less than 1000m
Up
kV
125
Rated frequency
f
Hz
50
Rated short time withstand current for main circuit
Isc
kA
31.5-1 s
Rated peak withstand current
Ip @50Hz
kA
80
Rated current busbar
Ir bb
A
3150
t
s
Internal arc classified
Arc duration
Classification
1
IAC A FLR
Degree of protection
Enclosure
IP4X
Between compartments (inner partitions)
IP2X
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
Other specifications
Refer to MV Switchgear data sheet
3.5
HV/MV TRANSFORMERS SPECIFICATIONS
Key Technical Characteristics
a) Rated Voltage

Primary (HV): 225 kV

Secondary (MV): 20 kV ± 2.5% (on-load tap changer or off-load tap changer)
b) Rated Power & Vector Group

Rated Power: 120 MVA

Vector Group: Typically Dyn11
c) Impedance & Losses

Short-circuit impedance (Ucc): approx. 10–12%

No-load losses: < 0.5%

Load losses: < 0.4%
d) Cooling Type

Cooling: ONAN (Oil Natural Air Natural) or ONAF (Oil Natural Air Forced), depending on thermal design/load
margin
e) Insulation Levels

Dielectric withstand:
o
HV bushings: withstand industrial frequency and lightning impulse per IEC 60076 / 62271
o
MV insulation: suitable for 21 kV systems
f) Noise Level
< 83 dB(A) at 1 meter if ONAN, < 90 dB(A) at 2 meter if ONAF
g) Accessories & Enclosure

Bushings: In compliance with IEC 60137 / IEC 60815

Oil conservator: With visible oil level indicator

Pollution class: Insulation creepage distances sized per site pollution level (Class I to III)
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3.6
HIGH VOLTAGE TYPE OF CABLES
The general specifications of the cables to be used are as follows:
 depending on the application, the cables may be :
o
single-core,
o
assembled in bundles,
o
three-pole,
 NFC 33-220 reference standards (copper or aluminium core),
 reference standards NFC 33-226 (aluminium core),
 radial field,
 PR type insulating jacket,
 metal screen per conductor,
 PVC outer sheath,
 rated voltage : 21 kV,
 insulation voltage: 24 kV.
3.7
LV CABLING OF MV ROOMS
3.7.1
EARTHING
The Contractor will carry out the earthing of all MV equipment (Cubicles) from the earthing distributors (located in each
room) to the equipment. These equipotential connections will be made of 35 mm² bare copper.
The equipotential connections between the MV substations - 35 mm ² bare copper - will be supplied, installed and
connected by the Contractor.
3.7.2
48 VDC AUXILIARY SOURCES AND DISTRIBUTION BOX
Supply, installation and connection of two 48 Vdc "rectifier-charger" and its distribution box for each MV room.
Each energy block will have an autonomy of 2 hours.
This "energy" unit is intended, in 2N, to supply the substation's MV Cubicles.
A distribution box will supply the following equipment:

Triggering and closing coil,

Control/command automatisms of the MV panel

Digital protection relay (Line),
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3.8
INSTALLATION TESTING AND COMMISSIONING
To carry out the services relating to FAT (Factory Acceptance Test), SAT (Site Acceptance Test) and IST (Integrated
Systems Testing), the Contractor shall refer to the project’s specifications.
As the IST is a process common to all the technical lots, the electrical lot will be responsible for its management,
coordination and delivery of the final reports to be attached to the file of completed works.
3.8.1.1
TESTING OF MV INSTALLATIONS
3.8.1.1.1
MV INSTALLATIONS
The Contractor must draw up two test books, one for factory tests and the other for on-site tests, which he submits to
the PC for approval. The latter reserves the right to add its own tests to the test books.

Factory acceptance
All costs incurred by this factory’s acceptance (travel and accommodation) shall be borne by this lot.
All MV tests must be carried out and supervised by a person certified for high voltage operations.

Verification of MV installations
They will focus in particular on:

o
compliance with the Special Technical Specification (STS),
o
compliance with worker protection (labor code)
o
the general appearance (paint, finish, welds, fixings),
o
compliance with dimensions, reservations for the passage of conduits,
o
....
Tests
The tests will validate the operation of all the equipment provided for in the prefabricated substation.
The following tests will be carried out (non-exhaustive list):
o
o
o

MV panel tests:

Powering up,

Cubicle operation (manual and automatic),

trip test,

interlocking tests,
Normal / Emergency control / command box:

testing of local and remote Cubicle control,

fault detection simulation,
48 Vdc sources:

powering up,

mains cut-off (taken over by the batteries),
Site verification and testing

Installation checks
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
o
Checking the positioning and fixing of the various equipment,
o
electrical connections (connection and laying of cables),
o
marking of equipment,
o
testing of all protection and safety devices (electrical, alarms),
o
calibration of protections (selectivity),
o
insulation control.
Functional tests
o
Checks that all equipment is working properly,
o
Verification of the reporting of all BMS points.
3.8.2
TRANSFORMER INSTALLATION TESTS
3.8.2.1
TRANSFORMER INSTALLATIONS
The Contractor must draw up two test books, one for the factory tests and the other for the on-site tests, which he
submits to the PC for approval. The latter reserves the right to add its own tests to the test books.

Factory acceptance
All costs incurred by this factory acceptance (travel and accommodation) shall be borne by this lot.
All transformer testing shall be carried out and supervised by a person certified in high voltage operations.

Verification of transformers installations
They will focus in particular on:

o
compliance with the Special Technical Specification (STS),
o
compliance with worker protection (labor code)
o
the general appearance (paint, finish, welds, fixings),
o
compliance with dimensions, reservations for the passage of conduits,
o
....
Tests
The tests will validate the operation of all the equipment provided for in the prefabricated substation.
The following tests will be carried out (non-exhaustive list):
o
Transformer tests:

Checking the protection of people against direct contact,

Insulation check,

Checking the correct operation of each component and the corresponding controls,

Checking the wiring and its identification,

Checking that the various components are correctly identified,

Measurement of no-load and load losses

Measurement of the transformation ratio

Measurement of the short-circuit voltage

Checking the control systems (temperature relays)
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
Checking the conformity of the execution with the approved plans,

Various checks such as sheet metal work, sealing, painting,
After the factory tests (routine + the above controls), a report will be drawn up by the Contractor listing all the values and
tests with the conclusions. These documents will be distributed to the PC and the Employer and integrated into Executed
Works File.


On-site verification and testing
o
Installation checks
o
Checking the nameplate
o
Checking the earthing system
o
Checking the interlocks
Functional tests
o
Checking the wiring of all controls
o
Checking the interlocks
o
Checking the opening of the circuits (upstream and downstream of the link)
o
Installation of a protection (downstream connection) to indicate that the equipment is going to be energized
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