A high voltage impulse happens when lightning strikes power lines on masts to cause an instantaneous surge of very high voltage. Although the high voltage impulse lasts only a split second it can damage insulation on any electrical equipment – such as transformers and switchgear – connected to the power line.

A high voltage impulse follows when lightning strikes

Damage from the high voltage impulse can result in the power grid experiencing a partial failure or blackout, leading to dissatisfied consumers and potentially high repair costs.

Impulse test on transformers, surge arrestors, isolators, etc.

High voltage impulse tests on transformers, surge arrestors, isolators and switchgear ensure that these components can withstand the instantaneous electrical surge and continue to operate reliably.

The high voltage impulse caused by lightning can be of either positive or negative polarity. A standard high voltage impulse reaches peak voltage after about 1.2 μs and decays to 50% of this peak voltage about 50 μs after the beginning of the impulse.

Impulse test with ISOBE5600 transient recorder

These requirements for an high voltage impulse test are best met with HBM’s ISOBE5600 transient recorder product which provides fiber-optic isolation as well as transient recorder functionality.

ISOBE5600 transient recorder for impulse testing

ISOBE5600 transient recorder

This measuring system comes with integrated fiber-optic isolation and includes transmitter and receiver units, as well as measurement and analysis software. The receiver has built-in memory and the equipment features a USB interface for connection to a PC. Learn more...

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