Tracing

Folks have been asking about the “business fit” for tracing tools. For background information on electric and gas networks, I’d recommend going to HowStuffWorks (www.howstuffworks.com) and searching on electric distribution and gas distribution.

As for the business “fit” for the traces…try this:

Electric

System isolation – absolutely useless in my experience…it’s simply too slow

Trace source/end – these are useful for identifying the substation circuit breaker that is feeding a particular circuit, or alternately for accumulating load points (transformers and meters) on circuit for outage reporting purposes.

Trace upstream/downstream – these are useful for finding the next device (source and/or load) on the line. Can be used to browse up or down on the circuit to find transformers, fuses, switches, open points, reclosers and sectionalizers and then get to them using the routing tool.

Trace upstream/downstream protective device – an upstream/downstream trace for protective devices (fuses, reclosers, sectionalizers and switches) only.

Phase trace – electric networks operate in three phases (alternating currents, sine waves, that are offset 60* from each other). The phases are alternately referred to as A, B, and C; 1, 2, and 3; or red, white, blue by different utilities. Hooking up an A phase device to a B phase line is potentially DEADLY, not to mention costly. Think about when you hookup a light switch the wrong way when you’re wiring your basement and you cause a short and burn out the switch. You walk away with a throbbing thumb due to the fact that you were only “stung” with 120 volts. The guys in the field would be dead after 4800 (4.8kv) – 13200 (13.2kv) volts coursed through them. A phase trace is designed to follow a particular phase or phase configuration. For instance, A, B, C, AB, BC, AC, or ABC. Transformers can be hooked up in configurations wye or delta configurations that combine phases to boost power. Iindustrial/agricultural machines and commercial lighting systems typically need three phase power. Homes are almost exclusively single phase.

Hydraulic (water/sewer/gas)

Valve isolation – useful for identifying the valves that need to be closed to isolate a section of pipe for replacement or repair.

Interactive isolation – the “new” tool that allows valves to be added/subtracted from the trace results to extend or constrain the trace. The main benefit of this is for in-field decision support surrounding accumulated load and the effects of planned and unplanned outages during damage restoration/repair efforts.

Pressure zone isolation – hydraulic networks operate on different pressure planes (water) and different operating pressures (gas). It’s useful to isolate the pressure zone during troubleshooting. Water pressure planes do not typically connect. As for gas, you don’t want to hook-up a high pressure line to an intermediate or low pressure line with out a pressure reducing valve. Regulator stations typically isolate pressure zones in a gas network.

Trace upstream/downstream – mainly for sewer since s*** flows downhill, you want to know which direction downhill is…sewer can also be pressurized (typically called “force” as opposed to “gravity”)

Trace next feature upstream/downstream – mainly for sewer and useful for locating manholes, vaults and clean-outs.

Traces that we’re missing…

Hydraulic – CP (cathodic protection) system trace – water and gas pipes are protected by anodes that are designed to rust out by drawing the oxidizing current off the bare (or coated) steel pipes. Pipe operators want to know where their cathodic networks are because they have to regularly inspect them for regulatory compliance. Rectifiers, anodes and test points are points on the CP network where readings are taken on current loss to determine if the anode is still active and doing its job. The recent news about the BP oil pipeline that rusted out and spilled crude oil on the North Slope of Alaska is evidence to why operators need to know about CP systems.

Electric – Circuit trace – similar to a phase trace, but following a particular circuit designation as opposed to phase designation. This is a safety consideration as well as an operations concern. The guys in the field might think that opening a switch on a section where they are doing a “hot line” job will kill power to that section of line, but in fact it’s still hot because of a switching operation that was done the previous week and it’s now fed off of a different circuit. Tracing the circuit would alert them to this. From an operations perspective, the guys in the field can also identify overloaded circuits and find tie switches that allow them to manually shift load.