In reference to the GPR voltage gradients around a substation during a close-in fault and the extreme drop-off point at the edge of the station ground grid, is there a possible touch (not step) potential hazard if a metal stake was planted into the ground within say 10 feet away from the fence...
Are there standards (IEEE, NESC) that require the need for an express (implying insulated) connection between the neutral bus in a switchgear and the Xo bushing of the transformer? There are thoughts that simply connecting the switchgear neutral bus which may be carrying 100 amps or more of...
I cannot pass IEEE80 touch potential criteria at a substation fence built on top of the property line adjacent to neighbors. I cannot move the fence inward three feet in order to get a horizontal ground conductor three feet out from it as this restricts our ability to get to the substation...
Our substation has a security fence (encloses all substation equipment) and a separate perimeter fence (around the edge of the property line). Both fences are separately grounded with the security fence ground tied to the substation ground grid. I am using WinIGS to evaluate the touch and step...
Are there any national codes or standards that say substation fences cannot be energized? We have some fences near transmission lines that have an induced voltage of between 6 and 12 volts when measured from a remote earth point.
Our substation rock is sized 3/4 to 1-1/2 (years ago it was larger) and some of the heavier utility trucks have a tendency to sink their wheels into the rock making traction difficult. Our normal depth is between 4 and 5 inched. Any ideas or suggestions?
IEEE80(2000) has Sf current split factors shown on page 153 for a Dist gnd of 25 ohms vs one for 200 ohms. The table on page 151 line 4 from the bottom says R=.322 and X=.242 for 25 ohms and then R=1.65 and X=.291 for 200 ohms (the far right column heading is wrong and should say Rdg=200).
If I...
We are empirically testing substation rock spalls for resistivity and come up with around 10,000 ohm-meters of resistivity. The IEEE80 uses a typical example of 2500 to 3000 ohm-meters for substation rock resistivity. Are we way off base? Our samples are 1-1/2" drain rock.
When going thru the Travis-Pattern Bus support catalog, some slip fitting supports will include the Static Eliminator springs if an "SE" is suffixed on the part number. They are supposed to push the bus up against the walls of the ring type support to eliminate chatter/vibrations and minimize...
We have a cell tower in a 15ft X 10ft fenced area with a buried horizontal ground conductor 2ft outside the fence and ground rods connected to it and the fence. This cell tower site has control boxes and equipment that need to be maintained by Ma Bell personnel. This fence is within 15ft of...
We just received a new substation switchgear and the control wiring to the feeder breakers (and generally everywhere) is #14awg. The control circuit is protected by a 30A breaker (per feeder breaker mfgr GE). The switchgear mfgr claims he is only obligated to follow ANSI C37.20.2 which says...
In our substations there is mixed nomenclature,including nameplates, over our control switches and pushbuttons. Sometimes it say "Open" and other times it says "Trip". Does anyone have a code, standard, or utility practice on a this? We haven't thought this was a big deal, but somebody...
We have been using 3000 ohm-meters for our crushed rock values as a typical from examples in IEEE80. However, we did tests of our crushed rock and came up with about 9600 ohm-meters. Our tested crushed rock is 1-1/4" in size and we wetted it prior to taking measurements. Has anyone else did...
We are very successful using WinIGS to design our substation grounding systems to comply with IEEE80. However, on small substations (80'X 80' square) we cannot get the touch and step potentials to be lower than the allowable. Small areas tend to have this problem regardless of how much...
When we examine the GPR gradient at a substation, there is a very steep drop-off at the edge of the grid. Has anyone protected people against this steep gradient by using commercially available insulation such as using rubberized "nugget chips" or a rubber sidewalk? Extending horizontal...
IEEE80(-2000)page 78, third and fourth paragraphs: "For a grounded Y on the secondary (distribution) side of a substation transformer, ground faults at the transformer low-side terminals circulate through the grid with negligible leakage current to the earth and thus no effect on the...
For those users of the WinIGS Integrated Grounding System program, where do you input the resistive properties of "X" depth of substation rock when evaluating the touch and step potentials at a substation?
