How to Select the Right SIS System

What Do  Letter Designations Mean on Solid Insulated Switchgear?

When electrical engineers select Solid Insulated Switchgear (SIS) for medium voltage systems, understanding the letter and number codes on GE equipment becomes essential. These designations are not random — they reveal critical information like:

 System ratings
 Installation type
 Interruption technology
 Protection capability
 Application environment

A correct interpretation ensures that the switchgear you select fully matches operational safety and performance requirements.

As a professional MV equipment manufacturer, Degatech focuses on advanced Solid Insulated Switchgear designed for compact substations, renewable energy systems, and modern utilities. With new safety, sustainability, and maintenance standards emerging, decision-makers must know exactly what these codes represent.

What Is Solid Insulated Switchgear?

Solid Insulated Switchgear (SIS) is a modern alternative to SF6 gas-insulated switchgear.
Instead of gas, it uses solid insulation materials such as epoxy compounds to encapsulate live components.

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Solid Insulated Switchgear = safer + SF6-free + longer life cycle

Degatech SIS technology delivers arc protection, reliable switching, and excellent endurance for medium voltage systems up to 40.5kV.

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Why GE Switchgear Letter Designations Matter

Every alphabet symbol on GE SIS part names conveys real engineering meaning.
Here are the main types you may encounter:

Example:

📌“GVS–24”
G = GE switchgear series
 V = Vacuum breaker
 S = Solid insulated
 24 = Voltage rating (24kV)

Most Common GE Designations Explained

Let’s decode typical industry codes frequently found on Solid Insulated Switchgear systems:

Voltage Ratings and Performance Codes Used by GE

These performance classifications determine whether equipment suits industrial, utility, or renewable energy demands:

Example:

IAC AFLR-20kA / 1s
→ The switchgear can withstand an internal arc facing front, side, and rear for 1 second
→ Critical indicator for substation operators

Application Scenarios of Solid Insulated Switchgear

Solid Insulated Switchgear has quickly become the preferred solution in:

Because SIS does not rely on SF6 gas, it significantly reduces environmental compliance risks and maintenance costs in long-term operations.

Degatech’s Solid Insulated Switchgear is built to meet modern sustainability standards and global MV power distribution demands.

Advantages of Choosing Solid Insulated Switchgear

To help engineers evaluate systems scientifically, here’s a performance comparison of different switchgear types:

Why SIS > GIS?
Because SF6 is now restricted in many countries, SIS represents the future mainstream choice.

How to Interpret Design Letters When Selecting GE Solid Insulated Switchgear

When reviewing a GE catalog, buyers should evaluate these 5 core aspects:

Insulation Type
S = Solid insulation → Preferred for compact layouts

Interruption Method
V = Vacuum interruption → High endurance and safety

Network Configuration
R = Ring main → Efficient distribution design

Protection Level
A / B ratings → Arc withstand performance

Voltage Code
24 / 40.5 = Grid compatibility confirmation

Example selection checklist:

By decoding these designations properly, engineers can avoid mismatch and unnecessary costs in installation and testing.

Degatech Solid Insulated Switchgear Solutions

Degatech delivers SIS products built for:

✔ Smart distribution automation
✔ Safety in compact areas
✔ Zero SF6 environmental pressure
✔ Long lifecycle performance
✔ Reliable operation in mission-critical grids

We offer:

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Installation & Maintenance Recommendations

To maximize operational reliability, we recommend:

 Thermal scanning before energizing
 Annual torque inspection for joints
 Partial discharge monitoring in high-risk environments
 Confirm arc protection zones correctly tagged
Maintain clean enclosure ventilation

Correct installation + predictive maintenance =
long lifecycle + cost efficiency

Frequently Asked Questions (FAQ)

Below are common technical questions customers ask when selecting Solid Insulated Switchgear and interpreting GE designation codes.

  What does “S” mean in GE switchgear models?

“S” represents Solid insulation, which means the switchgear uses epoxy resin or other solid dielectric materials instead of SF6 gas.
It indicates stronger environmental compliance and reduced gas leakage risks.

 What is the difference between “V” and “L” in GE switchgear?

Engineers must verify if the equipment supports fault interruption or load switching only.

 What does the number after the letters indicate?

It indicates the maximum rated voltage that the Solid Insulated Switchgear can operate in:

Selecting incorrect voltage level may lead to insulation stress and operation failure.

 What is BIL in GE SIS selection?

BIL stands for Basic Impulse Level.
It measures resistance to high-energy lightning and switching surges.
Higher BIL = Stronger transient protection.

 Why choose Solid Insulated Switchgear over SF6 GIS?

Because SIS offers:

 No greenhouse gas
 Reduced leakage and compliance risk
 Lower maintenance
 Comparable arc protection and lifetime

It is now the preferred solution in most compact MV substation projects.

 Does Degatech provide customized Solid Insulated Switchgear?

Yes. Degatech offers:

✔ Custom configurations
✔ Smart monitoring integration
✔ Flexible feeders and automation
✔ Voltage rating options up to 40.5kV

We support OEM/ODM programs for global power distributors.

How to Order Solid Insulated Switchgear from Degatech

To ensure correct model selection, engineers should prepare:

 Rated system voltage and frequency
 Short-circuit capacity (kA)
 Number of incoming/outgoing feeders
 Protection relay strategy
 Indoor or outdoor installation
 Arc classification requirements

Degatech provides professional pre-sales engineering support to help you configure the ideal SIS system.

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Conclusion

GE letter designations on Solid Insulated Switchgear provide critical insight into:

 Insulation material
 Breaking technology
 Network configuration
 Voltage level and performance rating
 Arc and environmental protection capability

Understanding these codes leads to safer, more reliable, and cost-optimized power distribution.

Degatech’s Solid Insulated Switchgear lineup provides a
modern, SF6-free and compact solution
designed for smart substations and sustainable grid development.