TVSS for TOV

[rnpatrick]

Are TVSS devices effective against overvoltage conditions caused by weather-induced faults in the utility?

I have a client who has experienced 3 incidents in the past 20 months. The first one the utility confirmed was caused by a high voltage line coming in contact with a lower voltage line due to a fallen tree.

The most recent time was after the big mid-Atlantic storm last weekend and it happened AFTER the storms had passed at 10 AM when there was not a cloud in the sky so I am highly doubtful it was lightening. Whatever it was, it literally blew the meter out of the base, taking the panel's cover with it.

All 3 incidents have caused extensive damage to a lighting control system - nothing super major in terms of equipment damage but each time it takes about a day to go around and replace the fuses in the control modules. (I designed and program the lighting system - that is my connection to this)

This system cost $30,000+ and needless to say after the last incident they are willing to invest in something to protect them from more loss.

TVSS systems are not my strong point. Will they protect from these types of situations? I have been asked for my opinion since if they call a contractor the answer will of course be 'yes'. If put in a TVSS and 6 months from now we are back out there replacing the fuses (or worse...) I'm going to have some explaining to do.

Thanks in advance for any pointers or suggestions you have. Much Appreciated.

 

[pwrtran]

TVSS, Transient Voltage Surge Suppression, by name it is meant for protect equipment under transient voltage conditions, which may be lightning transient or switching transient. Standard lightning waveform is 1.6/50 micro sec and switching surge is 8/20 micro sec. It is just expensive lightning arresters combo, if you know the principle how lightning arresters work, it is same. When one experienced incident as you described, it is an indication that you may also have some grounding and bonding issues in addition to protection coordination.