The major problems revolve around the fact that the arcing or flares can occur at “normal operating voltages” and while can be influenced by transient events like lightning, it is actually more of a design and maintenance issue, as well as the normal deterioration of insulating materials.  Even such things as air pollution can have an effect.

 

So it is very unlikely that traditional SPD will have much effect in stopping arcing or flash-over, especially in high voltage applications.  In fact the only type of surge suppressor that can work at these high voltages is basically a spark gap which uses the arcing to short excess voltage to ground

 

HOWEVER

 

Arcing and flash-over occurrences in high voltage circuits are targets to cause many instances of down-line equipment failures, especially in monitoring and control hardware operating at much lower voltages and using highly sensitive electronic and computer controls.  There does not even need to be a direct connection of the flash-over or arcing currents to cause damage in low voltage, sensitive equipment, many problems arise because the unnaturally high currents caused by arcing can induce transients in nearby low voltage circuits.  This is much the same way that lightning can “induce” high voltages in nearby circuits and cause damage even without a direct hit.

 

Therefor it is imperative all lower voltage control, monitoring and measuring equipment be equipped and protected by high quality, long lasting, and properly sized transient voltage surge suppressors.  Proper sizing means that the peak surge current capabilities should be conservative, and MULTIPLE LEVEL of TVSS devices must be employed to mitigate any transients that are caused by flash-over or arcing.  Multiple levels are required because TVSS devices with high current withstand capabilities tend to allow higher let through voltages (the voltage that gets past the SPD), while lower current TVSS devices are much better at lower let-through voltages, they cannot stand up against the higher surge currents that might be present without an upstream device.  This “stair step” approach has proven to be the ONLY effective method to adequately protect sensitive equipment from transient surges.

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