Zero Sequence Currents through single phase to ground connected load
Zero Sequence Currents through single phase to ground connected load
(OP)
I work for a PUD in Washington and we had two feeders out of one substation that tripped at the same time. One was faulted, the other wasn't. I'm now reviewing the causes of sympathetic tripping and my notes (from an SEL class I took a couple years ago) state that zero sequence fault current from a phase to ground fault can flow through single phase to ground connected load. There's no further explanation in the notes as to how this can happen. Can anyone provide an explanation? I understand how the zero sequence current can flow through a three phase bank with grounded Y on the high side and delta on the low side, but struggling with the single phase connections.






RE: Zero Sequence Currents through single phase to ground connected load
RE: Zero Sequence Currents through single phase to ground connected load
RE: Zero Sequence Currents through single phase to ground connected load
Could you describe in a little more detail the events that occurred? What type of relay tripped each feeder?
RE: Zero Sequence Currents through single phase to ground connected load
RE: Zero Sequence Currents through single phase to ground connected load
RE: Zero Sequence Currents through single phase to ground connected load
RE: Zero Sequence Currents through single phase to ground connected load
RE: Zero Sequence Currents through single phase to ground connected load
RE: Zero Sequence Currents through single phase to ground connected load
RE: Zero Sequence Currents through single phase to ground connected load
RE: Zero Sequence Currents through single phase to ground connected load
I work for a PUD in Washington and we had two feeders out of one substation that tripped at the same time. One was faulted, the other wasn't. I'm now reviewing the causes of sympathetic tripping and my notes (from an SEL class I took a couple years ago) state that zero sequence fault current from a phase to ground fault can flow through single phase to ground connected load.
///Yes, this is correct. The single phase fault will inject current into ground. Any single phase load of the same faulted phase to ground fault will provide the path to the zero sequence current back to the source of the zero sequence current. Often, it is easier to find the answer in textbooks that cover this topic, e.g.:
William D. Stevenson, Jr., "Elements of Power System Analysis," 3rd Ed., McGraw-Hill Book Co., 1975, Chapter 13 "Unsymmetrical Faults"\\\
There's no further explanation in the notes as to how this can happen. Can anyone provide an explanation?
///Try to get a good textbook since the literature that you are reading is presupposing that you have a pertinent background.\\\
I understand how the zero sequence current can flow through a three phase bank with grounded Y on the high side and delta on the low side, but struggling with the single phase connections.
///This needs background covering Unsymmetrical Faults.\\\
RE: Zero Sequence Currents through single phase to ground connected load
RE: Zero Sequence Currents through single phase to ground connected load