We are installing a new 2500 kVA, 13,800-480Y/277 V transformer (solidly grounded) that will feed a new 480 V, 3000 A lineup of switchgear (3 phase, 4 wire). The transformer is located outside the building and will be cable connected to the new switchgear inside the building via underground...
We are adding a 2.5 MVA, 4.16 kV generator to an existing system. The 4.16 kV system is fed from a 12.47 kV-4.16 kV, 5 MVA transformer with a 400 A neutral grounding resistor. How should the generator neutral be grounded (high resistance, low resistance, etc.)? What IEEE standards would apply...
I have a question about how much current would flow for a ground fault on an ungrounded capacitor bank. The cap bank is a 12.47 kV, 1800 kVAR and it is being fed from a transformer with a 1000 A neutral grounding resistor. If one of the capacitors internally faulted to ground, how much ground...
We have a 4.16 kV MCC fed from a 5 MVA, 5.6% impedance transformer. There are several motors on this MCC and we are looking to add a new motor of undetermined size. I understand the voltage dip requirements for the new motor, but my question is what is the allowable voltage dip on the 4.16 kV...
We had a fault on a feeder off the the secondary of a Delta-Wye transformer that caused the primary overcurrent relays to operate. The relays that operated on the primary are electromechanical relays, so they don't provide any indication as to the fault current values. The secondary relays are...
