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South Side ComEd substation gets digital upgrade

Updated: April 28, 2013 7:13AM



When a circuit blows on the ComEd system, workers often have to “walk the line,” following the electric cable on foot from a substation until they find the fault.

A newly-upgraded substation near 81st and Wallace on Chicago’s South Side will make that job easier by identifying the location of a problem to within about 600 feet.

This year, the substation, which serves 28,000 customers, became the first such station in Chicago to be upgraded from electromechanical to digital technology.

As a result, electric service will be more reliable and when problems occur they will be fixed faster, the utility said.

The substation serves customers on the South Side, an area which has had more frequent and longer power outages than the North Side.

That’s one of the reasons the Wallace substation was chosen for an upgrade.

“We want to improve the overall reliability of the South Side of Chicago,” said Richard Gordus, ComEd’s Smart Grid Manager.

Instead of mechanical circuit breakers similar to those in most homes and apartments, the new substation was outfitted with microprocessor-controlled relays.

Connected to a central computer, the new relays can provide enough information for software to figure out where a short circuit or fault occurred. The new technology also monitors its own performance and can give warnings of problems about to happen.

“This allows us to be more proactive than reactive,” said ComEd’s Gordus during a recent tour of the substation. “These devices are giving us loads of information. We’re using it to be able to improve our processes, reduce our costs, understand what’s going on in the substation and improve its overall reliability.”

It is the second substation in ComEd’s system to get the digital upgrade. The first was in Oak Park and unlike the one in Chicago, is connected to residential “smart meters” as part of a pilot project.

Smart meters eliminate the need for meter readers, immediately report power outages at the customer level and allow users to pay less for off-peak power usage.

Customers this year started paying more on their bills to cover the cost for smart meters, but systemwide installation has been delayed until 2015 because ComEd says it not getting enough money to pay for the program.

However, the utility is going forward with a program to perform digital upgrades to 10 more substations over the next five years at a cost of $7 million each. The next two upgrades will be in west suburban Franklin Park and in the Clearing neighborhood near Midway Airport.

The digital substations can work with or without smart meters, but their performance improves when linked to smart meters. Likewise smart meters can work with or without digital substations.

ComEd has more than 250 substations similar to Wallace, so it will likely be many years before they are all upgraded.

“The [older] electromechanical relays work fine, but the question is now is at some point you have to start modernization,” said ComEd’s chief operating officer Terry Donnelly. “We’re committed to have a year-over-year program to modernize our stations to improve reliability.”



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