There is a solution to the transient over voltage spikes and phase voltage instability in an ungrounded power system. Phaseback was designed for just such a problem. We have them in our facility with all 35 of our 2000 kva power transformers protected and haven't had the instability generally...
With ungrounded delta power systems we have added Phaseback to our power system and our phase voltages are now balanced to ground and our overvoltage problems stopped. The link is: http://www.applied-energy.us
I hope this helps
Bill
I have worked with ungrounded power systems for over 30 years and have only one positive way to measure ground current and I use this EVERY time we go looking for the cause of our grounding problem. We start at the substation and measure the current in the ground wires in our secondary cables...
