High Voltage (HV) Projects

High Voltage Engineering for Renewable Energy Sites

End-to-end HV engineering support for solar farms, large C&I sites and utility-scale renewable energy projects.

HV ENGINEERING SERVICES

The most safety-critical element of any large renewable project

High-voltage infrastructure is one of the most complex and safety-critical aspects of large-scale renewable energy projects. Mistakes in HV design, protection coordination or commissioning sequencing can cause equipment damage, outages, or serious safety incidents.

GreenBox provides HV engineering support from initial design through to commissioning — coordinating with DNSPs, electrical contractors and project developers to deliver compliant, on-time HV connections.

Our HV scope includes ring main units, HV switchgear specification, transformer coordination, HV protection design and complete DNSP connection management.

HV SCOPE

Ring Main Units (RMUs)

Specification, procurement support and commissioning coordination for ring main units and HV switching equipment.

HV Switchgear Specification

Technical specification of HV switchgear including circuit breakers, disconnectors, earthing switches and associated protection.

Transformer Selection & Spec

Selection and specification of power transformers, including vector group, impedance, tap changer and protection requirements.

HV Protection Design

Complete HV protection scheme design including relay selection, settings calculation, grading coordination and commissioning verification.

DNSP Coordination

Technical engagement with DNSP HV network planning teams — managing the technical approval process for your HV connection.

HV Commissioning Support

On-site HV commissioning support including pre-energisation checks, functional testing and DNSP hold point inspection management.

11–33kV

VOLTAGE RANGE

All States

COVERAGE

FAT Incl.

EQUIPMENT TESTING

WHY GREENBOX

What separates GreenBox HV engineering

Dedicated HV Engineering Team

GreenBox maintains a team of engineers with specific HV design and commissioning experience — not generalist electrical engineers rotating through projects.

DNSP Relationship Management

Our existing relationships with HV network planning teams at major Australian DNSPs enable more direct technical dialogue — reducing the back-and-forth that delays HV connection approvals.

Complete Documentation Package

Every HV project is delivered with a complete documentation package — including HV drawings, protection schedules, SWMS, asset registers and commissioning records.

ENGINEERING PROCESS

Eight-stage HV delivery process

HV Design Brief

Scope definition, voltage level confirmation, connection topology, DNSP requirements and project schedule alignment.

Network Assessment

Review of DNSP network at the proposed connection point — fault level, available short circuit capacity, protection settings, and metering requirements.

Equipment Specification

Technical specification of all HV equipment — RMUs, switchgear, transformers, protection relays and associated low-voltage equipment.

DNSP Coordination

Technical engagement with DNSP HV planning team — including pre-application meetings, design reviews and technical query responses.

Detailed Design

Full HV design package including single-line diagrams, HV protection schedules, relay settings calculations, and installation drawings.

Procurement Support

Technical review of equipment supplier proposals and factory acceptance testing (FAT) witnessing for critical HV equipment.

Installation Supervision

On-site supervision of HV installation works — ensuring compliance with design, safe work practices and DNSP technical requirements.

HV Commissioning

HV energisation management including pre-commissioning checks, protection testing, DNSP hold point management and energisation certificate.

KEY BENEFITS

What GreenBox HV engineering delivers for your project

Safety-Critical Expertise

HV engineering requires a depth of safety knowledge and technical experience that generalist engineers cannot provide. GreenBox’s HV team works exclusively on high-voltage projects.

First-Pass Approvals

Our structured DNSP coordination process and pre-submission technical reviews consistently achieve first-pass approvals for HV connection applications.

Complete Documentation

Every HV project is delivered with a complete as-built documentation package — suitable for ongoing asset management and future DNSP interactions.

Procurement Support

We assist with equipment procurement — reviewing supplier proposals, specifying factory acceptance testing requirements, and witnessing FAT for critical equipment.

On-Site Presence

GreenBox engineers are present on site during critical HV milestones — installation supervision, pre-energisation checks, and DNSP hold point inspections.

Cost Certainty

Fixed-price HV engineering packages are available for standard project scopes — giving you cost certainty in your project budget from the outset.

INDUSTRIES

Sectors where we deliver HV projects

CASE STUDY

4MW Solar Farm — South Australia

CHALLENGE

A 4MW ground-mount solar farm in South Australia requiring a complex 11kV HV connection to the SA Power Networks distribution network. SAPN required a custom protection scheme due to the site’s proximity to a sensitive network section.

SOLUTION

GreenBox designed the complete HV package including 11kV ring main unit specification, transformer selection, protection relay design with custom grading coordination to SAPN requirements, and managed the full SAPN HV connection application process.

RESULT

HV connection approved by SAPN on first submission. System energised on schedule — within the project’s contractual commissioning deadline.

On Schedule

ENERGISED WITHIN CONTRACTUAL DEADLINE

COMMON QUESTIONS

HV Project FAQs

Common questions about our HV engineering services for renewable energy projects.

What HV voltage levels do you work with?

GreenBox HV engineering services cover 6.6kV, 11kV, 22kV and 33kV distribution voltage levels — the most common HV connection voltages for large C&I and solar farm projects in Australia. For projects requiring 66kV or transmission-level connections, please contact us to discuss scope.

Do you handle DNSP negotiations for HV connections?

Yes. HV connection negotiations are typically more involved than LV embedded generation applications — requiring direct engagement with DNSP HV network planning engineers. GreenBox manages this entire process, including pre-application meetings, technical submissions, and query responses. Our existing relationships with DNSP HV teams enable more efficient technical dialogue.

Can you specify third-party HV equipment, or do you supply it?

GreenBox provides engineering specification and procurement support for HV equipment — we are not an equipment distributor. We prepare detailed technical specifications for RMUs, switchgear, transformers and protection equipment, review supplier proposals, and support factory acceptance testing. You retain the flexibility to source equipment from your preferred suppliers.

What documentation is provided at project completion?

Every GreenBox HV project is delivered with a complete documentation package including: as-built single-line diagrams, HV equipment data sheets, protection relay settings records, commissioning test reports, DNSP connection agreement, energisation certificates, SWMS and safe work procedures, and an asset register for ongoing maintenance reference.

Do you attend HV commissioning on site?

Yes. GreenBox engineers are present on site for HV commissioning milestones — including pre-energisation checks, protection relay functional testing, DNSP hold point inspections and initial energisation. Our on-site presence at commissioning is a standard inclusion in our HV engineering packages, not an optional add-on.

What Australian states do you provide HV engineering in?

GreenBox provides HV engineering services across all Australian states. Our experience covers projects in NSW, QLD, VIC, SA, WA, TAS and NT — across all major DNSP service areas. Interstate travel and accommodation is included in our fixed-price project quotations.