Dear all:
We are installing a generating center to supply loads to an industrial Plant. The generating center is gas internal combustion motors based, totaling 21 MW. Generators terminal voltage is 4.16 kV, there are installed step up transformers to bring voltage to 34.5 kV.
Our 4.16 and...
Hello:
We have an electrical substation and a generation power plant 600 meters away.
We need to detect the change of state of the contact of an electromechanical relay in the substation at the power generation plant in less than 30 miliseconds. Really, there are 10 discrete signals running...
At least, theoretically, in case of an external single phase to ground fault, only Io current shall circulate in the three phases of the Z-transformer and then no current to flow outside of the delta connected CT´s, towards O/C relays.
For single phase (or multiphase) faults in the...
You could consult "IEEE Guide for safety in AC substation grounding. IEEE Std80-2000."
This standard states the procedure to calculate the allowable step and touch voltages and tables with typical surfaces material resistivities.
If I well understand your question, you can have a look to Walter A. Elmore, "Zero-sequence mutual effects on ground distance relays and fault locators", 46th Annual Protective Relaying Conference at the Georgia Institute of Technology, Atlanta, Georgia, April 29-May 1, 1992.
