transient voltage

What are Transient Voltages?

Last Updated by LaoRen

This post deals only with the aspects related to energy metering.

Transient voltages are short time surges in the a.c. power supply. They typically last a few milliseconds and the voltage can reach several thousand volt. A transient is by definition shorter than half cycle.

transient voltage
voltage transient

Causes for transients

There are two major groups of transient voltages.

Power system switching transients

Power system switching transients can be separated into transients associated with:

  • major power system switching disturbances, like capacitor bank switching
  • minor local switching activity or load changes in the power distribution system
  • resonating thyristors circuits
  • short circuits
  • arcing faults to the grounding system

Lightning transients

  • direct lightning stroke
  • induction due to an indirect lightning stroke
  • nearby lightning-to-earth discharge

Energy meters can not detect a voltage transient. The event is too short. Most power quality analyzers are designed to capture surges in voltage.
The energy meters are protected to surge effects according to IEC61000-4-5.
For certain regions additional external arresters can be added during meter installation.

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