Mobile substations keep electricity flowing so crews can safely work on equipment

EnergyLines March 2018

It isn’t often that you see these big vehicles out in the field, but when you do, they are doing their fair share of work. A mobile substation is a large piece of equipment, replicating the job of a stand-alone substation, that can be transported to a designated location, set up and then used for an undetermined amount of time (usually one to seven days) so that service is not interrupted while work is performed on the substation.


Hoosier Energy has six functioning mobile substations, the first one dating back to the 1970’s. Each mobile substation has a designated voltage and current rating. These mobile substations range in voltage to match the substations’ transmission voltage (34.5, 69, 138, 161kV). When needed, each mobile station is transported to the designated location by a semi and then set up to maintain uninterrupted service. The equipment is designed and dispatched to eliminate or minimize any perceived performance differences by end consumers.


Each mobile substation is ready to be deployed. They are protected in designated bays – out of the weather at the Operations Center. Maintenance is performed at scheduled times to ensure each mobile substation is performing as designed. This maintenance can take anywhere from a couple of days to a little over a week, depending on the amount of work planned. Maintenance is routinely done during periods when their use is minimized due to system conditions. It is important to perform preventative maintenance because these mobile substations are doing the same work that the full substation is providing, but in a much smaller area, with the added risk of being physically transported.


In addition to the mobile substations, there are also accessory trailers with equipment that may be required for each individual job. A regulator trailer is available to assist with voltage control. This device monitors the voltage, watching for when it goes up or down and then adjusts accordingly. There is also a trailer with breakers set up for individual use when a mobile substation has a need for more than two breakers. In some cases, all three trailers (mobile substation, regulator and breaker trailers) may need to go out for one job.


Hoosier Energy has a complete mobile workforce to ensure that the 18-member co-ops have the proper tools at their disposal to make sure their members stay connected.


These substations receive maintenance at scheduled times to ensure each is performing as designed.


Download PDF