Rockwill Switchgear — C-GIS, GIS, Metal-Clad, and Traditional AIS: Distinctions and Core Differences

Core Differences — Detailed Comparison

• GIS: SF₆ gas insulation; integrated modular pipe-type structure; no independent cabinet units; assembled by bay modules.
• Rockwill C-GIS: Eco-friendly gas sealed inside a stainless steel gas compartment — fully insulated, fully enclosed. Modular cabinet structure; gas insulation significantly reduces electrical clearances; flange-to-flange connection between cabinets for easy extensibility.
• Traditional AIS (Metal-Clad): Air insulation; live parts exposed. Multi-compartment metal-clad structure; large air clearances required to meet air insulation requirements → large cabinet size, low space utilization.

• Rockwill C-GIS: Gas compartment protection rating IP65 or higher — fully dustproof and moisture-proof. Extremely strong environmental adaptability; resistant to dust, moisture, salt spray, and corrosive gases. Suitable for underground tunnels, coastal areas, chemical plants, high-altitude locations, and other harsh environments.
• Traditional AIS (Metal-Clad): Enclosure protection rating typically IP3X to IP4X — basic protection only. Prone to insulation degradation and component corrosion in humid, dusty, or salt-spray conditions. Additional protective measures required in harsh environments.

Internal Arc and Safety Protection

• Rockwill C-GIS: Internal arc rating typically reaches IEC's highest Class A (accessible to personnel). High-voltage live parts are completely enclosed inside the metal housing. Combined with independent pressure relief channels, three-position disconnector, and mechanical interlocks — physically eliminating risks of electric shock or inadvertent entry into live compartments.
• Traditional AIS (Metal-Clad): Metal compartments and pressure relief channels provide some internal arc protection, but high-voltage components still have exposure risk. Under extreme conditions, there is a safety hazard of foreign object contact or inadvertent personnel contact with live parts.

Loss of Service Continuity (LSC Classification)

• Rockwill C-GIS: Typically achieves LSC 2B — failure or maintenance of any high-voltage compartment does not affect the continued operation of other high-voltage compartments.
• Traditional AIS (Metal-Clad): Mostly LSC 2B — the metal-clad structure inherently supports compartmentalization, but depends on the specific compartment arrangement and busbar connection method.

Operation, Maintenance, and Installation

• GIS: Factory pre-assembled, site-assembled by sections; short installation period; sealed gas compartment is maintenance-free; periodic gas pressure monitoring required.
• Rockwill C-GIS: Assembly, gas filling, and testing completed at the factory. On-site work limited to section connection — easy installation. Primary high-voltage circuit is maintenance-free; gas pressure monitored online via density relay only — minimal maintenance effort, suitable for unattended scenarios.
• Traditional AIS (Metal-Clad): On-site assembly, busbar connection, and insulation testing involve complex procedures. Retrofit or capacity expansion requires disassembly of cabinets and busbars — difficult construction. Requires regular scheduled outages for insulator cleaning, contact wear inspection, and insulation testing — high maintenance cost.

Cost and Application Scenarios

• GIS: Very high procurement cost; used only for large high-voltage hub substations and backbone transmission projects.
• Rockwill C-GIS: Higher unit procurement cost than traditional AIS, but smaller footprint and maintenance-free operation — lower total lifecycle cost. With the "dual carbon" strategy, C-GIS using eco-friendly gases (dry air, etc.) to replace SF₆ is accelerating in adoption. Suitable for urban underground substations, utility tunnels, compact substations, renovation of old distribution rooms, land-constrained core areas, and harsh industrial environments.
• Traditional AIS (Metal-Clad): Low equipment procurement cost. Suitable for conventional substations with ample space, clean environments, and well-established maintenance conditions — general factory and commercial building distribution rooms.

IEE Business Full Lifecycle Management System

IEE Business is Rockwill's digital O&M platform for intelligent power distribution. Through real-time equipment status monitoring and big data analysis, it enables full digital control and management from installation, operation, and maintenance to retrofit — tightly integrating hardware equipment with O&M management.

Rockwill C-GIS comes with matching sensors and intelligent terminals pre-integrated at the factory — natively compatible with the IEE Business system. For traditional AIS (metal-clad), retrofitting is mostly required after installation to access the platform, with data easily becoming fragmented and the system lacking integration.

The system can monitor in real time: gas density, moisture content, and temperature inside the gas compartment, as well as circuit breaker mechanical characteristics and primary loop contact temperature — transmitted directly to the platform via built-in sensors. The core value is achieving a "transparent gas compartment": the previously sealed and invisible internal state becomes transparent and visible through the platform. The system continuously analyzes pressure trends and issues early warnings at the onset of gas leakage, preventing development into an insulation fault.

This transforms the O&M model from traditional "periodic maintenance" to "condition-based maintenance" — scheduling outages based on platform diagnostic recommendations rather than blindly following a fixed period. Meanwhile, from factory test data and installation/commissioning records to every online monitoring history curve, the system automatically consolidates them into a digital twin archive, generating one-click equipment health reports and achieving closed-loop lifecycle management.

(B) Support for Traditional AIS (Partial or Retrofitted)

The monitoring scope for traditional AIS is relatively limited. Typically, only temperature sensors can be added to monitor cable compartment contacts and busbar compartment local temperatures, or partial discharge sensors can capture partial discharge signals in air insulation. The core insulation medium (air) cannot be monitored online — condensation, moisture ingress, and tracking still rely on manual inspection. Even after connecting to a management system, planned preventive maintenance tests cannot be fully replaced. Data is fragmented, making it difficult to form assessment models directly linked to equipment life.

(C) Support for GIS

High-voltage GIS has its own advanced condition monitoring systems, but these focus more on complex techniques such as UHF partial discharge and SF₆ gas composition analysis. They operate at higher voltage levels and greater monitoring depth than the IEE Business medium-voltage scope — independent systems with higher cost.

Summary: Three-Dimensional Selection Guide

Based on the above analysis, the selection logic can be summarized across three dimensions: Insulation Medium — International Standard — Lifecycle Management.

1. Insulation medium: If maintenance-free operation, harsh-environment resistance, and small footprint are required, choose C-GIS. If cost is sensitive and the environment is controllable, choose traditional AIS.

2. International standard: IEC/German/British standard projects can directly apply the corresponding products. North American projects must distinguish between "Metal-Clad" and "IEEE gas-insulated switchgear".

3. Lifecycle management: If digital O&M, condition-based maintenance, and unattended operation are required, choose Rockwill C-GIS with built-in IEE Business.

Three Typical Selection Paths

1. High reliability, low maintenance, digital distribution room: When the project demands high reliability, small footprint, IEC/German/British standards, and a full lifecycle management system — select Rockwill eco-friendly gas C-GIS + IEE Business platform for a transparent, maintenance-free distribution room.

2. Cost-priority, conventional distribution: When the project is cost-sensitive, the site has ample space, a well-established periodic inspection regimen, and deep online monitoring is not required — select traditional AIS (metal-clad) compliant with the applicable standard (IEEE Metal-Clad or IEC metal-clad).

3. EHV hub substation: Enter the GIS domain directly. The monitoring system is built independently to high-voltage standards. IEE Business is not directly applicable.

Edited From：Garca