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High Voltage Disconnectors

145 kV to 550 kV

Safe, visible isolation for transmission substations and critical HV assets.

The outdoor AC disconnectors are designed to establish a visible, no load isolation point in transmission networks, enabling safe maintenance and switching on busbars and lines. Models cover 145, 170, 252, 363, 420 and 550kV systems with options for integrated earthing switches and configurations suited to line, bus, bypass and special layouts.

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Designed for Extra‑High Voltage Transmission Networks

Insulect’s high‑voltage disconnectors (145–550 kV) provide visible isolation, exceptional insulation performance, and robust mechanical endurance suitable for extreme service environments. With pollution Class IV capability and high lightning impulse withstand ratings (up to LI 1675 kV at 550 kV), these units support reliable switching on transmission lines and busbars.

What We Solve For

  • Provides safe, visible isolation for EHV systems under no‑load conditions
  • Manages small inductive/capacitive currents and bus transfer switching, where required
  • Maintains consistent mechanical performance with sealed rotating assemblies
  • Ensures long‑term reliability in highly polluted or corrosive environments
TECHNICAL

Features & Functionality

SR-JXB
Proven Insulation Performance

Creepage distances sized for pollution Class IV with power frequency and lightning impulse withstands up to PF 740 kV / LI 1675 kV at 550 kV, ensuring reliable external insulation in harsh environments.

GW7B
Maintenance Free Rotating Assemblies

Sealed bearing housings and closed rotating bases prevent ingress of moisture, dust and corrosives, keeping operating torque stable over time.

GW23B
High Integrity Contacts

Self cleaning or self clamping copper alloy fingers with silvered surfaces minimize contact resistance and heating; force balanced designs resist vibration and wind induced movement.

GW22B
Flexible Site Fit & Layouts

Portfolio spans horizontal center, vertical “scissor”, single arm telescopic, and 3 post flip type mechanisms; options include left/right/both side earthing, manual or motor operation, and bus transfer current capability where required.

Functionality & Options

  •  Visible isolation under no‑load conditions

  • Opening/closing small inductive/capacitive currents (0.5–2 A)

  • Bus‑transfer current switching

  • Equipment‑ or line‑side integrated earthing switches

  • Motorised or manual operation

  • Auxiliary contacts, electromagnetic locks, heaters, and RTU/PLC I/O support

Key Technical Specifications

  • Voltage range: 145 kV to 550 kV

  • Current ratings: typically 1250–3150 A at 145 kV; 1600–4000 A at 252 kV; 3150–5000 A at 363–550 kV

  • Short-circuit duration: 2–4 seconds, depending on voltage class.

  • Mechanical endurance: 10,000 operations 

  • Lightning impulse withstand voltage (LIWV): Up to 1800 kV

EXPERIENCE

Our Projects featuring Insulect Substations

Explore our project highlights to see where Insulect Substations are making an impact.
For tailored advice on whether this solution suits your network, please connect with our team here.

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Aldoga Solar Farm
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Wambo Wind Farm

Where you'll find our Substations

You'll find Insulect-supplied and installed Substations across Australia and New Zealand -- our locally built Insulect range and imported Sieyuan range.

ADVANTAGES

Why Choose Insulect for Substation Disconnectors

Our 145–550 kV high‑voltage disconnectors provide safe, visible isolation for transmission networks and EHV substations. Designed for line, transformer, and busbar applications, they offer strong insulation capability and robust mechanical design suited to harsh climates, high‑pollution sites, and high‑altitude operation.
 
Proven High‑Voltage Performance
These models deliver top‑tier insulation strength, with power‑frequency and lightning‑impulse withstand levels reaching up to 1675 kV, meeting demanding Class IV pollution and international standards. Multiple series are certified as achieving internationally advanced performance levels, ensuring stable operation under tough conditions.
Durability & Mechanical Reliability
High‑conductivity alloy conductors, sealed maintenance‑free bearings, and corrosion‑resistant components ensure long‑term dependability. Many designs offer 10,000‑cycle mechanical endurance and maintain stable torque even under wind, ice, seismic activity, or altitude effects.
Flexible Configurations for Any Layout
Available in center‑break, scissor‑type, flip‑type, and telescopic formats, this range supports a wide variety of substation configurations. Options include single/double earthing, motor or manual drives, and suitability for both rigid and flexible bus systems. Models also handle inductive/capacitive small‑current switching and bus‑transfer duties where needed.
IMPLEMENTATION

Services & Support

Insulect offers comprehensive services and support for the products we manufacture and specialise in, enhancing value for local utilities, major energy users, equipment manufacturers, and service operators. 

LOCAL TECHNICAL TEAM

Our local technical team provides exceptional support and expertise, ensuring quick response times and personalised service to tackle any challenges that may arise during project execution.

  
ENGINEERING DESIGN

Our team utilises advanced technology and industry knowledge to develop innovative and efficient high-voltage switchgear solutions, customised to fit the unique requirements of each project.


  
PROCUREMENT & LOGISTICS

We facilitate smooth procurement and logistics processes by sourcing from trusted, proven partners and coordinating timely deliveries, ensuring projects remain on schedule and within budget.


  
TESTING & COMMISSIONING
Professional testing and commissioning support ensure that every high-voltage switchgear system functions safely and reliably, adhering to all regulatory standards and client expectations.
  
TURNKEY PROJECT DELIVERY

We are able to oversee every phase from concept to completion, providing comprehensive solutions that simplify complex projects and ensure successful outcomes.

  
FACTORY VISITS
We facilitate client visits to our local manufacturing sites here in Australia, as well as overseas, for initial inspection as well as factory acceptance testing.
  
FROM THE BLOG

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We built for reliability, safety, and compliance — our products are designed to perform in the toughest environments. Talk to our team to ensure you're specifying the right product for your application.
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