Jrmcritical
May 22, 2019, 08:48 AM
I'm sure this post will seem very redundant to some, but one can never reiterate enough the importance of testing prior to energizing.
Just within the past two weeks, we were called to two different sites to assess equipment which failed either upon startup or during the commissioning process.
Site 1: We were called to the "scene" of a newly installed 6mVA double ended substation which experienced a fault immediately upon energizing within the local utility's PT cabinet. Failure analysis testing revealed that a damaged winding shorted to the case of the PT resulting in a short circuit. Had these PTs undergone a simple resistance test, this would have been averted.
360361
362363
364
Site 2: (Not as "cool" of a picture, but definitely avoidable.) At the request of a large utility provider, we were requested to perform a failure analysis study and replace bussing, preventative maintenance etc... due to what was described as a faulty CT cabinet. Examination found that the voltage taps for the utility metering were incorrectly wired resulting in a phase to phase short circuit. Luckily the metering wire burned up fairly quickly preventing a catastrophic failure of the unprotected utility bussing, however the utility metering technician was rushed to a local hospital due to molten copper blowing off in his face. Had adequate testing and commissioning been performed this situation would have also been averted.
Basis of this post, Next time an electrician says third party testing/commissioning is a waste of money, point out the situations that you've encountered and could have prevented with basic testing techniques.
365
What installation related issues have you come across We'd love to hear and learn from your experiences in the field.
Stay safe
Just within the past two weeks, we were called to two different sites to assess equipment which failed either upon startup or during the commissioning process.
Site 1: We were called to the "scene" of a newly installed 6mVA double ended substation which experienced a fault immediately upon energizing within the local utility's PT cabinet. Failure analysis testing revealed that a damaged winding shorted to the case of the PT resulting in a short circuit. Had these PTs undergone a simple resistance test, this would have been averted.
360361
362363
364
Site 2: (Not as "cool" of a picture, but definitely avoidable.) At the request of a large utility provider, we were requested to perform a failure analysis study and replace bussing, preventative maintenance etc... due to what was described as a faulty CT cabinet. Examination found that the voltage taps for the utility metering were incorrectly wired resulting in a phase to phase short circuit. Luckily the metering wire burned up fairly quickly preventing a catastrophic failure of the unprotected utility bussing, however the utility metering technician was rushed to a local hospital due to molten copper blowing off in his face. Had adequate testing and commissioning been performed this situation would have also been averted.
Basis of this post, Next time an electrician says third party testing/commissioning is a waste of money, point out the situations that you've encountered and could have prevented with basic testing techniques.
365
What installation related issues have you come across We'd love to hear and learn from your experiences in the field.
Stay safe