Technical Support Provided by Taili Electric
1. What is Medium Voltage Switchgear?
Medium voltage switchgear is used in electrical systems with voltages ranging from 6 kV to 35 kV
It can be thought of as the "main power management hub".
Main functions:
- Switching electrical circuits on and off
- Protecting equipment from short circuits and overloads
- Safe disconnection and isolation of equipment for maintenance
Common voltage levels in practice:
-10 kV — distribution networks
-35 kV — industrial and substation applications
2. Main Types of Medium Voltage Switchgear
The three most common types on the market are:
-KYN28 (12 kV, withdrawable cabinet)
- GIS (Gas-Insulated Switchgear)
- KYN61 (40.5 kV, for 35 kV systems)
Type | Name | Voltage | Insulation | Application |
KYN28 | Classic cabinet | 12 kV | Air | Cost-effective solution |
GIS | Gas-insulated switchgear | 12/24 kV | SF₆ gas | Compact solution |
KYN61 | 35 kV cabinet | 40.5 kV | Air | High-voltage systems |
2.1 KYN28 (12 kV Metal-Clad Switchgear)
KYN28 Metal-Clad Switchgear is the most common type of switchgear in 10 kV systems.
Construction
The cabinet is divided into four compartments:
- Instrument compartment
- Circuit breaker compartment
- Busbar compartment
- Cable compartment
All compartments are separated by metal partitions.
Main components:
- Vacuum circuit breaker (withdrawable type)
- Earthing switch
- Current transformer (CT)
- Microprocessor-based protection
Summary:
KYN28 is the standard, cost-effective solution for 10 kV distribution.
2.2 GIS (Gas-Insulated Switchgear)
GIS is fully sealed equipment where all high-voltage parts are enclosed inside a metal housing with SF₆ gas.
Features:
- Fully sealed construction
- High protection against moisture and dust
- Compact dimensions
Monitoring system:
- Gas pressure sensor
- Leak alarm system
Summary:
GIS is a compact and reliable solution for harsh environments.
Applications:
- Coastal areas
- Underground substations
- Space-constrained locations
- Wind and solar power generation
2.3 KYN61 (40.5 kV Switchgear)
KYN61 is used in 35 kV and higher systems.
Construction:
- Metal enclosure
- Withdrawable circuit breaker
- Larger dimensions
- Enhanced insulation
Main components:
- 40.5 kV vacuum circuit breaker
- Voltage transformer (PT)
- Surge arresters
Summary:
KYN61 is used in main substations and 35 kV industrial systems.
3. Comparison of KYN28, GIS, and KYN61
Parameter | KYN28 | GIS | KYN61 |
Voltage | 12 kV | 12/24 kV | 40.5 kV |
Insulation | Air | SF₆ gas | Air |
Construction | Withdrawable | Sealed | Withdrawable |
Size | Medium | Small | Large |
Environmental resilience | Medium | High | Medium |
Maintenance | Simple | Nearly none | Normal |
Cost | Low | High | Very high |
4. Advantages and Disadvantages
4.1 KYN28
Advantages:
- Low cost
- Simple maintenance
- Widely used
Disadvantages:
- Large size
- Sensitive to humidity
4.2 GIS
Advantages:
- Compact size
- High reliability
- Pollution resistant
Disadvantages:
- High cost
- Complex repair
4.3 KYN61
Advantages:
- Rated for 35 kV
- High power capacity
- Robust construction
Disadvantages:
- Large dimensions
- High cost
5. How to Select Medium Voltage Switchgear?
Selection criteria:
- Voltage level
- Operating environment
- Available space
- Budget
- Maintenance requirements
Application recommendations:
Scenario | Recommended Equipment |
10 kV factories | KYN28 |
Humid / coastal areas | GIS |
Underground substations | GIS |
Wind power | GIS |
35 kV systems | KYN61 |
6. Frequently Asked Questions (FAQ)
Q1: What is the difference between GIS and AIS?
AIS uses air insulation, while GIS uses SF₆ gas. GIS is more compact and resistant to environmental conditions.
Q2: Is KYN28 an air-insulated switchgear?
Yes. KYN28 belongs to air-insulated switchgear (AIS).
Q3: Why is GIS more expensive?
Reasons:
- Complex enclosure manufacturing
- Use of SF₆ gas
- Pressure monitoring system
- High precision assembly
Q4: Which equipment is better for coastal areas?
GIS is the best solution because it is fully sealed and protected against moisture and salt.
Q5: Can KYN28 and KYN61 withdrawable trolleys be interchanged?
No. They have different dimensions and voltage ratings.
7. Taili Electric Comprehensive Solutions
Taili Electric has over 30 years of experience in medium voltage equipment.
Main products:
- KYN28A-12
- GIS 12/24 kV
- KYN61-40.5
Company advantages:
- Complete electrical equipment supply
- Compliance with IEC standards
- International project experience
- Custom engineering solutions
Equipment selection support
To assist with equipment selection, please provide:
- Voltage level
- Environmental conditions
- Room dimensions
- Project budget
We will prepare a technical solution and system diagram.
