Engineered for medium voltage Air Insulated Switchgear (AIS), our Sensor Insulators perform a dual critical role: providing robust mechanical support for busbars and acting as a high-precision capacitive voltage divider. Manufactured using the advanced APG process, these components deliver real-time voltage presence signals to Live Line Displays (VPIS/DXN), ensuring operator safety and IEC-compliant system monitoring from 12kV to 40.5kV.
Our sensor insulators are rigorously tested to meet IEC 61958 and IEC 60660 standards. Below are the detailed specifications for our standard series. We also offer custom design services to match specific creepage distances or capacitance requirements.
| Parameter | Unit | 12kV Series | 24kV Series | 40.5kV Series |
|---|---|---|---|---|
| Rated Voltage | kV | 12 | 24 | 40.5 |
| Max. Working Voltage | kV | 12 | 24 | 40.5 |
| Power Freq. Withstand Voltage (1min) | kV | 42 | 65 | 95 |
| Lightning Impulse Withstand Voltage (BIL) | kV | 75 | 125 | 185 |
| Partial Discharge (at 1.2Um/√3) | pC | ≤ 10 | ≤ 10 | ≤ 10 |
| Parameter | Specification | Notes |
|---|---|---|
| Coupling Capacitance (C1) | 15pF – 150pF | Standard tolerance: ±10% or ±5%. Customizable to match DXN/VPIS. |
| Dielectric Dissipation Factor | < 0.04 | Measured at ambient temperature. |
| Voltage Division Ratio | Customized | Designed to ensure secondary output voltage meets 100V or specific indicator input requirements. |
| Secondary Terminal | M4 / M5 Screw or Faston | Shielded terminal design to prevent interference. |
| Parameter | 12kV Standard | 24kV Standard | 40.5kV Standard |
|---|---|---|---|
| Height | 130mm / 140mm / 145mm | 210mm / 225mm | 300mm / 310mm |
| Creepage Distance | ≥ 240mm | ≥ 480mm | ≥ 810mm |
| Bending Failure Load | ≥ 4 kN | ≥ 8 kN | ≥ 12 kN |
| Top Insert Thread | M10 / M12 | M12 / M16 | M12 / M16 |
| Torque Strength | > 40 N·m | > 60 N·m | > 80 N·m |
Our sensor insulators function based on the Capacitive Voltage Divider principle. Within the solid epoxy resin body, a precision metal screen is embedded during the APG casting process to acting as the high-voltage coupling capacitor (C1).
When the busbar is energized, this internal capacitor forms a series circuit with the input impedance (C2) of the connected Live Line Display (VPIS). Through voltage division, the dangerous high voltage (e.g., 10kV) is stepped down to a safe, low-voltage signal (typically 10V–100V). This signal drives the neon or LED indicator, providing a reliable visual warning of voltage presence without direct high-voltage contact.
Why leading switchgear manufacturers trust our sensor insulators for their critical safety monitoring.
The Challenge: Traditional hand-casting methods often cause capacitance drift, leading to dim indicators or false alarms.
Our Solution: We utilize Automated APG Clamping and laser-positioned inserts. This guarantees the distance between electrodes is microscopic precise, controlling capacitance deviation within ±5% for consistent signal output.
IEC 61958 Compliant
The Challenge: High-voltage environments are filled with Electromagnetic Interference (EMI), which can distort low-voltage signals.
Our Solution: Our design features a fully shielded secondary terminal. By grounding the base plate, we create a “Faraday Cage” effect around the output, ensuring the voltage signal remains pure and unaffected by internal cabinet noise.
ISO 9001 Certified Factory
The Challenge: A sensor failure isn’t just a broken part; it’s a potential busbar short-circuit accident.
Our Solution: Safety is binary. Every batch undergoes Power Frequency Withstand Voltage and Partial Discharge testing (≤ 10pC). We ensure the epoxy insulation is void-free, eliminating the risk of internal breakdown over decades of service.
100% X-Ray Inspected
Not all Live Line Displays (VPIS) are created equal. Different types (e.g., DXN-Q for mandatory locking vs. DXN-T for prompting) have different input impedance requirements.
If Capacitance is too low: The indicator light will be dim or fail to trigger.
If Capacitance is too high: The output voltage may exceed safety limits, damaging the display. Key Rule: The output voltage is determined by the ratio of the sensor’s capacitance (C1) to the display’s impedance (C2).
Eliminate compatibility anxiety. We don’t just sell standard parts; we tailor the sensor to your system.
Custom Range: We can adjust the internal C1 capacitance from 15pF to 150pF (Standard is often 18pF or 24pF).
How to Order: Simply provide the model number or rated input capacitance of your intended Live Line Display. Our engineers will calibrate the APG mold insert to match it perfectly.
🔗 Looking for compatible displays? Check our Switchgear Accessories page.
Grounding is Mandatory: The secondary output terminal (usually M4/M5) MUST BE GROUNDED if it is not connected to a display device. Leaving it open-circuited creates a floating voltage risk.
Torque Control: When installing busbars on top, adhere to the recommended torque (e.g., 40 N·m for M12) to prevent cracking the epoxy resin head.
Shielding: Ensure the base installation plate is properly grounded to maintain the shielding effect against electromagnetic interference (EMI).
Technically yes (higher insulation is safe), but the capacitance output might be too weak to trigger the 12kV display. It is best to match the rated voltage.
Unlike CTs, capacitive sensors are generally safe if open-circuited, but the terminal may accumulate a floating voltage. It is recommended to connect it to the display or ground it.
We perform a power-frequency withstand voltage test while simultaneously measuring the partial voltage output to ensure the capacitor is active and accurate.
Don’t compromise on safety. Whether you need standard sensors or custom capacitive dividers for specialized equipment, our engineering team is ready to assist.
