Testing vacuum bottles with high voltage

A vacuum interrupter (also known as a vacuum tube or vacuum bottle) is the core component of medium- and high-voltage circuit breakers.
Current interruption and arc extinction occur inside a vacuum chamber, ensuring reliable and fast disconnection of fault currents.

This technology is widely used in power generation, distribution networks, railways, arc furnaces, and industrial installations.
Due to the absence of gas or oil, vacuum interrupters require minimal maintenance and deliver very high efficiency.

Why test a vacuum interrupter?

Proper operation of a circuit breaker is critical.
If a breaker fails to interrupt a fault current in time, this can result in:

• Damage to equipment and installations

• Increased risk of fire or explosion

• Unnecessary downtime and high repair costs

• Serious hazards for personnel and surroundings

Although vacuum interrupters are extremely reliable, factors such as moisture, contamination, or leakage
can adversely affect their performance.
For this reason, manufacturers and international standards (IEC/IEEE) recommend performing an insulation integrity test.

How does the vacuum interrupter test work?

The insulation integrity test (or dielectric withstand test) verifies whether the vacuum interrupter can withstand high voltages without breakdown or failure. This test is performed with the breaker in the open position.

Two test methods exist:

• AC testing: complex and cumbersome due to the high currents required, resulting in equipment that is typically heavier and larger in size.
• DC testing: simpler, more reliable, and better suited for diagnosing vacuum interrupters.

Therefore, the industry typically chooses DC test equipment.

The VABO-80: compact vacuum interrupter tester

HighTest developed the VABO-80

The VABO-80 is a lightweight test device designed to test vacuum interrupters with a DC voltage of up to 80 kV.

Advantages of the VABO-80

• Compact and user-friendly design
• Clear on-screen Pass/Fail indicator
• No misinterpretations due to environmental factors such as humidity
• Option to retest with reversed polarity
• Available in a battery- and printer-equipped version (VABO-80B) for field applications

Typical Test Procedure

1. Ensure the circuit breaker under test is safely positioned.
2. Connect both the vacuum interrupter and the test unit to the same grounding point.
3. Set the test voltage according to the manufacturer’s specifications.
4. Perform the test using the selected voltage and duration.
5. Observe the results and repeat for all poles.

If no insulation failure is detected, the VABO-80 clearly displays “Test Passed.”

If your application requires higher test voltages or extended testing capabilities, the Smart Hipot HP80KV from Megabras is an excellent alternative to consider.

Main Specifications of the Smart Hipot HP80KV

• Test voltage: 2,000 V to 80,000 V (DC)
• Maximum leakage current: up to 10 mA
• Programmable parameters: voltage, leakage current limit, ramp (up/down), test duration
• Remote control via Android device (Bluetooth)
• LED “Pass/Fail” indicator, safety features such as emergency stop and spark detection
• Modular design (separate control and high-voltage modules) for increased operator safety

Which One to Choose?

If your application demands higher leakage currents or greater flexibility in test configuration, the Smart Hipot HP80KV is a powerful option to consider alongside the VABO-80.

Conclusion

Regularly performing a vacuum interrupter test is essential to ensure the reliability and safety of switching equipment. With the VABO-80 or the Smart Hipot HP80KV, you have a compact, precise, and user-friendly solution for verifying the insulation integrity of vacuum interrupters quickly and reliably.

Need advice on the right test setup for vacuum interrupters? Contact IONIO for application-specific guidance.