The KENJING PT isolating switch is a gas-insulated, medium-voltage isolator for potential-transformer bays. It delivers stable isolation at 12 kV, 630 A, with 20 kA/4 s or 25 kA/3 s thermal withstand, 50/63 kA peak/closing, and low ≤ 30 µΩ main-circuit resistance for accurate metering and safe maintenance.
Key Features & Advantages
MV insulation integrity: Power-frequency withstand 42/48 kV (to ground/phase-to-phase & across contacts) and lightning impulse 75/85 kV ensure clear visible isolation in PT compartments.
Fault-duty capability: The PT isolating switch supports 20/4 s or 25/3 s short-time withstand and 50/63 kA making/peak, aligning with typical 12 kV feeder fault levels.
Low resistance path: ≤ 30 µΩ main circuit reduces ratio error influence on PTs and limits thermal rise.
Mechanical durability: 5,000 operations for the isolating/earthing function; 1.25 bar sealed gas box enhances arc-quenching margins in enclosed PT cubicles.
Application fit: Designed as a gas-insulated isolating switch for PT outgoing/VT draw-out cells and ring-main units requiring compact isolation.
Why Choose KENJING
Purpose-built design: The PT isolating switch geometry, interlocks, and earthing positions are optimized for instrument-transformer protection and safe test/maintenance states.
Repeatable quality: Each PT isolating switch is routine-tested for dielectric, timing, contact resistance, and pressure tightness to maintain fleet consistency.
Lifecycle support: Drawings, interlock schematics, mounting kits, and spares simplify retrofit into existing medium voltage isolation switch cabinets.
Specify the KENJING PT isolating switch for your 12 kV PT bays. Contact our engineers for interface drawings, wiring details, and delivery scheduling.
NO | ITEM | UNIT | PARAMETERS | REMARKS |
1 | Rated Voltage | kV | 12 | |
2 | Rated Current | A | 630 | |
3 | Rated Breaking Current / Thermal Stability Time | kA/s | 20/4 ；25/3 | |
4 | Rated Peak Withstand Current | kA | 50/63 | |
5 | Rated Short-Circuit Closing Current | kA | 50/63 | |
6 | Power Frequency Withstand Voltage: To Ground / Phase-to-Phase | kV | 42 | |
7 | Power Frequency Withstand Voltage: Across Breaker Contacts | kV | 48 | |
8 | Lightning Impulse Withstand Voltage: To Ground / Phase-to-Phase | kV | 75 | |
9 | Lightning Impulse Withstand Voltage: Open Contact | kV | 85 | |
10 | Main Circuit Resistance | μΩ | ≤30 | |
11 | Isolating / Earthing Switch Mechanical Life | order | 5000 | |
12 | Gas Box Pressure | bar | 1.25 |
