Clarion HV/MV Substation EPC Specification Package

This document provides a structured technical specification for the EPC delivery of HV/MV substations in Serbia under Clarion Engineers’ (clarion.engineer) engineering, QA/QC, and grid-compliance framework.

Part 1 — General Requirements

1.1 Scope of Work

This specification covers the design, procurement, manufacture, delivery, installation, testing, commissioning, energization, and handover of a 110/35/20/10 kV HV/MV substation in Serbia, including:

• Primary equipment (transformers, switchgear, busbars, disconnectors, instrument transformers)

• Secondary systems (protection, control, automation, SCADA, metering)

• Civil works (foundations, structures, fencing, drainage, trenches, control building)

• Grid-connection compliance (EMS / DSO requirements)

• Integration with plant SCADA and dispatch centres

• Commissioning, reliability testing, and performance guarantees

EPC delivery is full turnkey, single-point responsibility.

Part 2 — Codes, Standards & Compliance

2.1 Relevant Standards

Substation must comply with:

• Serbian grid code requirements

• IEC HV/MV standards

• EU safety, EMC, and environmental directives

• Clarion QA/QC, ITP and HSE frameworks

The most stringent rule always applies.

Part 3 — System Design Requirements

3.1 Single-Line Diagram (SLD)

EPC must provide:

• Full SLD (HV/MV/LV)

• Busbar configuration

• Transformer connections

• Protection zones

• Earthing and fault current studies

3.2 Rated Parameters

Typical Serbian substation ratings:

Actual values must be confirmed with EMS/DSO.

Part 4 — Primary Equipment Specification

4.1 Power Transformers

Ratings:
110/x kV, 20–40 MVA typical
ONAN/ONAF cooling
Vector groups per grid code
OLTC ±10–16%

Requirements:
Oil: inhibited mineral or ester
Cooling control & fans
Online monitoring (temperature, gas, moisture)
Buchholz relay
Oil level, PRD, winding/oil temp
EU efficiency-class compliance

4.2 High-Voltage Switchgear (110 kV)

Options: GIS or AIS
Minimum 31.5 kA short-circuit
SF₆ monitoring (GIS)
Motorized disconnectors
Interlocking schemes
IEC 61850-ready

4.3 Medium-Voltage Switchgear (35/20/10 kV)

Metal-clad, withdrawable
Vacuum breakers
Internal arc classification AFLR
Busbar segregation
SCADA integration
CT/PT compartments

4.4 Instrument Transformers

Accuracy per metering/protection class
Oil-filled or cast resin
Insulation levels per Serbian category

4.5 Surge Arresters & Earthing

Metal-oxide arresters
Grounding system design including:
step/touch limits, resistance criteria, and lightning protection.

Part 5 — Secondary Systems Specification

5.1 Protection & Control

Protection functions include:

• Transformer differential (87T)

• Distance/line protection (21/21N)

• Overcurrent (50/51/50N/51N)

• Busbar protection (GIS optional)

• Breaker failure (50BF)

• Auto-reclosing

• Backup zones

Requirements:
Redundant CPUs
Dual communication channels
GPS/IRIG-B time sync
Disturbance recorder
IEC 61850-native devices

5.2 SCADA & Automation

EPC must deliver:

• Local HMI

• Dispatch centre connectivity

• IEC 61850 / 60870-5-104 protocols

• Cybersecurity (firewalls, VLANs, access control)

• Event and disturbance logs

• Historian

5.3 Metering

Revenue metering (import/export)
Accuracy: Class 0.2S
Utility-approved metering panels
Integration to TSO/DSO gateway

Part 6 — Civil & Structural Works

Includes:

• Control building

• Transformer foundations & bunds

• GIS/AIS platforms

• Cable trenches & ducts

• Fencing

• Access roads

• Stormwater drainage

• Fire protection

• Oil containment pits

• Substation lighting

Part 7 — Electrical Installation Works

Includes:

• MV/HV cable routing

• HV terminations & joints (certified jointers)

• Control wiring

• Optical fibre installation

• Panel mounting

• Earthing grid

• Bus ducting (GIS/AIS)

Part 8 — Testing & Commissioning Requirements

Commissioning follows Clarion’s ITP.

8.1 FAT (Factory Acceptance Tests)

Transformer FAT
GIS/AIS FAT
MV switchgear FAT
Relay configuration FAT
SCADA simulation
Clarion witnesses all Hold Points (H).

8.2 SAT (Site Acceptance Tests)

Visual inspection
Insulation resistance
Ratio/polarity testing
Relay functionality
Interlock checks

8.3 HV Testing

Power-frequency withstand
Partial discharge
Contact resistance
Continuity
Primary & secondary injection

8.4 SCADA & Protection Testing

End-to-end tests
GOOSE/MMS verification
Failover tests
Trip/close sequences
Alarm/event simulation

8.5 Grid Synchronization Tests

Voltage/frequency matching
Reactive control verification
Fault ride-through
PQ compliance

Failure to pass = non-completion.

Part 9 — Documentation

Contractor must provide:

• AFC design files

• As-built documentation

• Cable schedules

• Relay settings

• SCADA logic

• FAT/SAT reports

• Commissioning records

• O&M Manuals

• Spare parts lists

Digital + hard copy required.

Part 10 — Guarantees & Warranty

24-month DLP
5–10 year latent defects
Performance guarantees for:

• Transformer losses

• Switchgear availability

• Protection reliability

• SCADA uptime

24/7 response team required.

Part 11 — HSE & QA/QC

Contractor must follow Clarion:

• ITP Matrix

• QA/QC Manual

• HSE Plan

• NCR/CAR system

• Audit program

• Lifting plans, method statements, risk assessments

Clarion performs continuous surveillance and signs all Hold Points.

Part 12 — Training & Handover

Training for:

• Operators

• Maintenance teams

• SCADA engineers

• Protection engineers

Includes:

• Classroom sessions

• Hands-on practice

• Emergency drills

Handover requires:

• FAC

• Closed punch list

• Full documentation

• Asset register

Part 13 — Optional Extensions

Clarion can integrate:

• Battery Energy Storage Systems (BESS)

• Hybrid plant controls

• Advanced PQ analytics

• HVDC/FACTS

• Digital twin

• Predictive maintenance