The HRG system on a medium voltage system limiting the ground fault magnitude to a current value of 10A with NGR and the design of the grounding transformer is of 3 limb construction.
but during a ground fault condition, the disturbance recorder measured around 86A.
Of course the breaker tripped. Does that mean the combined zero sequence impedance (of the external resistor and the internal zero sequence impedance based on transformer construction) got reduced during the fault?