Detecting if the Neutral Ground Resistor (NGR) is shorted is something that must be checked at the Ground Fault Protecting Relay. The typical way to do this is to inject a DC component and to measure the voltage drop in the NGR. If no voltage drop is seen, it is assumed that the NGR is shorted and the relay trips. I would like to have Wye-connected PTs, used to monitor the quality of line to ground voltage and NGR monitoring with NGR short circuit condition detection at the same time on a 4160 V transformer secondary.
Having Wye-connected PTs may confuse the ground fault detection relay as for the DC component the PTs provide a low impedance parallel path which can be confused with a shorted NGR and this must be avoided.
Is adding a Potential transformers Ground resistor (PTGR) the only way to achieve both things? Wouldn't this affect the reading of the system monitoring the quality of line to ground voltage?
Update: There are also PTs that are build with a capacitor voltage divisor on their primary but I haven't found any operating at 5 kV