Switching hazards associated with leading power factor
Switching hazards associated with leading power factor
(OP)
I would appreciate any advice on a potentially hazardous situation we have been experiencing during switching operations. While breaking a station tie on a 23kv system utilizing three single 900 amp solid blade disconnects we are experiencing some undesireable failures on several different feeders. We are breaking station ties between two stations fed by two different transmission voltages (140kv and 238kv)on a distribtion voltage of 23kv using the S&C Loadbuster tool. On a great deal of occassions the tool has failed, sometimes totally destroying and melting the tool. We have worked extensively with S&C and it is not the fault of the tool or lack of maintenance. Could the leading power factor create some type of transient that would cause the tools failure? Would some type of gang operated switch resolve this issue? If so what would you reccommend? So far the injuries have been minor as a result of the switching failures. The regulators at the station have been addressed before switching. The "obvious" switching hazards have been adddressed and we are still experiencing the same problem without any pattern. The switching operations failures are never consistant. Thanks for any advice.






RE: Switching hazards associated with leading power factor
RE: Switching hazards associated with leading power factor
RE: Switching hazards associated with leading power factor
If this tie switch is remote from both substations, there is really no ideal way of setting the voltage regulators for opening the tie, since the actual voltage and phase angle at the switch is unknown.
What is current rating of the Loadbuster? It sounds like the current be broken is just more than the tool can handle.
I don't see that leading power factor (where exactly?) is going to the cause of this problem.
"The more the universe seems comprehensible, the more it also seems pointless." -- Steven Weinberg
RE: Switching hazards associated with leading power factor
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If we learn from our mistakes I'm getting a great education!
RE: Switching hazards associated with leading power factor
RE: Switching hazards associated with leading power factor
"The more the universe seems comprehensible, the more it also seems pointless." -- Steven Weinberg
RE: Switching hazards associated with leading power factor
RE: Switching hazards associated with leading power factor
I apologize for not keeping my posting current. I was ill for a couple of days and have been playing catch up since. I have attached a file with a photo of one of the many failed tools. This one obviously is a catastophic failure, most have not been as bad but a few have been worse. I will attempt to answer some of the posted questions but first I would like to Thank everyone for their advice. I have worked with S&C to find a solution to this ongoing problem and they have been excellent. It has been concluded the problem must be in the system, not the tool. The S&C Loadbuster has been in use for more than 50 years and is used around the world. The tool is capable of breaking 900 amps. Our loadbusters are maintained on a regular basis as per manufacturers recommendations. It is difficult to answer the question of ampereage through the switch at time of opening because of the large number of switching failures. Please remember we are breaking a station parallel not dropping load but load transfer. The problem only occurs on our 23kv system fed by the two different transmission voltages. The problem does not exist on our 13.2 kv (phase to phase) system. Both are wye systems. I hope this along with the attched pictures will be of some assistance. Thanks again.
RE: Switching hazards associated with leading power factor
RE: Switching hazards associated with leading power factor
Some measurements of these currents and/or analysis of the network might suggest a way to minimize the problem.