Non-Seg Bus Project

Florida

While performing emergency repairs, our crew was called upon by a Florida generating station to do a full inspection and cleaning on its non-segregated bus system. Upon arrival, after checking the non-segregated bus system for standing water, the team took out the flex braids to facilitate a hi-pot test.

As we prepared to cryogenically clean the non-seg bus, we replaced nine of the insulators. Upon further inspection of the insulators, SE Energy discovered that the braids in the neutral box were mismatched.  Different size braids were also found inside the building on one phase. In the neutral box, the bus transition bars were found to be corroded, and the termination sections were not silver plated.

Our team removed covers from the inside portion of the bus for access and then did a complete cryogenic cleaning of both the inside non-segregated bus system and the insulators before re-installing them with new gaskets and hardware.

The bus bars within the neutral box were copper bolted to aluminum conductor tabs. SE Energy recommended an optimal solution would be to cryogenically clean these copper adaptor bars and best practice was to re-silver plate the termination ends.

The condition of insulators on the bus that is outside the building walls of the non-segregated bus system was very poor. Bolts were found completely rusted out, and as these insulators were being removed, some of the inside threading was found to be damaged.  After cleaning what was still suitable for re-use and replacing what wasn’t, our team discovered the original rusted bolts in the insulator were silicon bronze. This speaks to why there was an issue of rusting.  Our team replaced the hardware with stainless bolts to prevent this issue moving forward.

Our crew silver-plated all of the bus transition pieces and the non-seg doghouse on top of the transformer.  After we finished silver plating the non-seg bus taps in the transformer doghouse, the insulator gasket inside the building was installed along with new hardware to the heater covers.

After finishing silver plating replacement, transition bars and flex braids were re-installed in the neutral compartment.