You’ve probably seen in-line manual switches on transmission lines and distribution lines.
Cleaveland price has gone a notch higher with a motorized version.
Although touted for use on transmission lines, I do not see any issues applying them inside substations too. This is because switches are normally operated as means to isolate after the breakers open. The best location for them would be on the line-exits.
Geotextile fabrics are quite common in lawn and garden applications. They allow water to pass through and block soil sediments from entering a corrugated drain pipe.
For substation application, a special fabric design allows rainwater to pass through but prevents oil from doing so. This feature makes it ideal for oil containment pits.
Traditional oil containment pits are expensive, requiring a concrete pit and a lift station (with oil separator valve) to contain oil, but discharge stormwater to a nearby culvert.
HICO – ProGIS Medium Voltage Gas Insulated Switchgear (GIS)
Got a critical facility? Short on space? Use this SF6 gas-insulated medium voltage gear.
The one shown in the video has a main and transfer bus configuration with one breaker and three line-disconnects. There are 3 additional ground switches. All this in a roughly 3feet by 6feet arc-resistant enclosure.
It isn’t cheap though. Each bay as shown is ~$150,000 (Gear only, excludes any building cost.)
Ever seen a faraday cage that clings to your body? Well, this is it. Do note that the “cage” is insulated from the body using an insulating layer.
This type of suit is useful in extra high voltage stations (230kV and above) where the electric fields are strong. A strong electric field builds a static charge on the unprotected body (similar to how you build a charge when you walk on a carpet in a dry condition). When you touch a grounded surface, like a breaker cabinet or structural steel, this built-up charge discharges – causing immense discomfort.
Unlike typical PPE where the boots are E-rated (i.e. electrically insulated from the earth), the boots for this application are conductive. There’s a separate pigtail attached to the jacket to connect to a reference, to create equipotential bonding.
These are also made for live line work – up to 1500V.
Copperweld – ArcAngel Ground Pigtails
Copperweld ArcAngel Ground Pigtail
Determining substation ground grid integrity is a grey area for many utilities i.e. some do it, others don’t. This is because the bare copper conductor is buried and when a transient does disperse through it, there’s no telling if the wire has fused (i.e. damaged itself). Unearthing a wire for inspection (for the sake of it) is out of the picture.
Copperweld’s team has produced a copper-clad wire that looks like aluminum but has a property where it discolors into a burnt look. This look is obtained when ~80% or above-rated fault current (it is designed to handle) flows through it. With this feature, you now know it’s almost time to replace it.
What you’re seeing (in the picture) is a ground pigtail or stinger that sticks out and grounds above-grade structural steel or equipment. For ground mesh, you still need to perform the typical integrity test (using the DC resistance test).
Air Insulated High Voltage Breakers
Clean air insulated high voltage circuit breaker from Siemens
Siemens circuit breaker ratings and availability
Saving the best for the last. We have only two vendors working to make high voltage circuit breakers that use air as an insulating medium inside their housing – MEPPI and Siemens.
It looks like only Siemens has the option to interrupt up to 63kA fault current (symmetrical) with a continuous current rating of 3150A inside a <245kV package.
