Arc Flash Mitigation 2

[nightfox1925]

We have a stepdown transformer connected to a downstream switchgear. This transformer is also fed from an upstream switchgear feeder. We are getting high arc flash energy values on both bus side and line side of the downstream switchgear. We have set a 'maintenance' setting on the main circuit breaker of the downstream switchgear to instantaneous and brought down the bus arc flash result to Level 2.

However, the line side of the breaker remains high. We tried to set the instantaneous of the uptream switchgear breaker to slightly override the transformer inrush but could not bring down the arc flash level on the line side of the secondary circuit breaker.

Does anyone have suggestion or other option to bring the line side A/F level?

 

[nightfox1925]

Yes we do have an HRG on the 600V.