In electrical power distribution systems, medium voltage (MV) switchgear serves as the critical node for controlling, protecting, and isolating electrical equipment. To ensure continuous grid stability and operational safety, the choice of switchgear insulation materials is paramount. High-performance insulation prevents electrical breakdown, suppresses arcs, and minimizes flashover risks, directly impacting the equipment's lifespan and reliability.
As a National High-Tech Enterprise and an audited supplier for state-level power grids , Zhejiang Gangheng Electric Company Limited (GangHeng) manufactures high-end switchgear (such as the KYN28-12 and KYN61-40.5 series) . In this technical guide, we will analyze the primary insulation materials utilized in modern MV switchgear and how they perform under demanding industrial conditions.
1. Key Insulation Materials Used in MV Switchgear
Modern medium voltage switchgear (ranging from 12kV to 40.5kV) utilizes a combination of solid, liquid, and gaseous insulation to achieve optimal dielectric strength within a compact footprint.
1.1 Epoxy Resin (Solid Insulation)
Epoxy resin is the cornerstone of solid insulation in indoor MV switchgear. Through Automatic Pressure Gelation (APG) technology, it is molded into busbar supports, spouts, and current/voltage transformers.
Dielectric Strength: Exceptional voltage resistance, making it ideal for 12kV and 40.5kV applications.
Mechanical Properties: High mechanical strength to withstand electrodynamic stresses during short-circuit events.
Environmental Resistance: GangHeng utilizes premium epoxy formulations that resist moisture, chemicals, and tracking, ensuring a long service life.
1.2 Silicone Rubber & Composite Insulators
Silicone rubber is widely implemented in cable terminations, busbar boots, and outdoor insulation components.
Flexibility & Hydrophobicity: Its natural water-repellent property prevents the formation of continuous conductive water films, minimizing leakage currents in high-humidity environments.
UV and Ozone Stability: Excellent aging resistance makes it perfect for harsh industrial environments, such as mining and petrochemical plants.
1.3 Engineering Plastics (SMC / DMC)
Sheet Molding Compound (SMC) and Dough Molding Compound (DMC) are fiber-reinforced thermoset materials used for phase barriers, arc chutes, and structural supports. They provide a balance of high flame retardancy, low smoke toxicity, and high structural rigidity.
2. Advanced Application in GangHeng's Core MV Switchgear Lineup
The selection and deployment of insulation materials directly dictate the footprint and safety of the final assembly. At GangHeng, our products are engineered according to stringent international benchmarks:
KYN28-12 Armoured Removable AC Metal-Enclosed Switchgear (12kV)
- Insulation Feature: Utilizes high-grade epoxy resin casting for all primary live parts. The busbars are fully sleeved with heat-shrinkable insulation tubes to prevent phase-to-phase flashovers caused by dust or small animals in factories and residential high-rises.
- Compliance: Fully compliant with GB/T standards and adaptable to ANSI/IEEE or BS standards based on EPC requirements.
KYN61-40.5 Armoured Movable AC Metal-Enclosed Switchgear (40.5kV)
- Insulation Feature: Designed for higher voltage thresholds (40.5kV), this model incorporates composite insulation structures to maximize air clearance and creepage distance while maintaining a space-saving layout.
- Proven Reliability: This robust insulation design allowed a major project in Tanzania to successfully power up within 5 days of unboxing, winning high praise from the client's CEO.
3. Selecting the Right MV Switchgear: Why Engineering Details Matter
For Engineering Procurement Contractors (EPCs), utility operators, and industrial buyers, choosing switchgear involves evaluating the operating environment against the insulation's capabilities:
| Operating Environment | Insulation Challenge | Recommended Solution |
|
Petrochemical & Mining |
Corrosive gases, heavy dust | Fully enclosed solid insulation / Epoxy-coated busbars + Silicone boots |
| Coastal / Tropical Zones | High humidity, salt spray | Hydrophobic Silicone Rubber & anti-tracking Epoxy elements |
|
Urban Substations |
Severe space constraints |
High dielectric strength composite insulation to reduce cabinet size |
Technical & Commercial Support from GangHeng
Engineering reliable power distribution requires a partner with manufacturing scale and technical agility. Zhejiang Gangheng Electric Co., Ltd. operates from a 5,000–20,000 m² state-of-the-art facility equipped with CNC punching, bending, and laser-cutting machinery to guarantee precision fabrication.
- Flexible Manufacturing: No Minimum Order Quantity (MOQ)-we accept custom non-standard orders starting from a single unit.
- Global Project Delivery: Experienced in exporting to regions including the Middle East, Central Asia, and Africa (e.g., Iran, Kyrgyzstan, Zimbabwe, Tanzania). We offer reliable lead times backed by guaranteed factory throughput.
- Quality Assured: Certified under ISO9001, ISO14001, and OHSAS18001 frameworks, with complete CQC and Type Test Reports available.
- For customized engineering drawings, single-line diagram evaluations, or pricing inquiries regarding our 12kV/40.5kV switchgear lines, please contact our engineering desk directly at zjgh2@ghswitchcabinet.com.
