T&D World Magazine

Voltage Testers Protect Field Workers

Commonwealth Edison is continually searching for new technology to make its linemen more efficient and safer in the field. Like other utilities, it’s essential for the company to equip its linemen with the proper tools to get the job done.

Oftentimes, the ideas for new products arise from needs in the field. For example, the utility partnered with HD Electric to create one device to detect downed lines and another to test voltage.

Detecting Downed Lines

During storm restoration activities, engineers and other non-field workers would go out with the linemen on patrol during storm restoration, and without a strong field background, they were at risk for contacting a downed wire. As linemen know, if an energized line falls on a wire fence, then it can energize the entire fence, putting anyone near it in danger of a severe injury or fatality.

To protect linemen and other employees, ComEd helped develop a product called a V Watch, which is now being used by utilities nationwide. For about a year, the utility and the manufacturer went back and forth to tweak and modify the device for field use.

Through the beta testing, the utility helped HD Electric to pinpoint the proper sensitivity for the live voltage indicator. In addition, ComEd also advised the company to make the product available to wear on a lanyard rather than clipped on a belt. That way, when the workers bent over to work, the device wouldn’t fall off to the ground. Also, the workers had a tendency to move it to the side of their belt, where it was more comfortable. The problem with this positioning, however, was that it needed to be in front so nothing would influence the integrity of the reading.

Now all employees, whether they work in the office or out in the field, are required to wear the device around their necks when they go out on patrol following a storm.

As soon as they arrive on site, they open up the shield on the device, push a button to test it, and then it is ready to detect energized objects. When they get near an energized fence or downed wire, it will beep and light up. Then if the user is a lineman, he or she will conduct a contact inspection and switch it off. If the worker who detects the energized line is a non-field employee, then he or she will contact the dispatch office about the wire down, give the location and a lineman will then de-energize the wire.

In the last few years, ComEd engineers have come across an energized wire in a backyard in a tree or bush. By wearing the V Watch, it alerted them before they got too close to the downed wire.

Reading Line Voltages

ComEd also helped to develop voltage indicators called the DV100 and DV500. Before using these single-point voltage indicators from HD Electric, the linemen were using a tester that beeped if the line was in a certain voltage range. If the linemen weren’t able to get the device down fast enough to lock in the reading, they would have to test the line all over again. Other times, the old tester would beep, and then the linemen wouldn’t know the exact voltage, so they would then need to return back up to the line with phasing sticks or a voltmeter. The lines also had a tendency to backfeed or show induction, which also disrupted the voltage readings.

With the newer tools, however, the linemen can pinpoint the exact voltage of the line and read the measurement from the ground. Instead of having to set up a truck to take the reading, they can attach the device to the end of a 30-ft extendo stick and check the voltage reading on the large digital screen.

When the product was first launched, HD Electric only had it available to read 100,000 V. The transmission linemen, however, needed a tool that could check higher voltages, so the manufacturer came out with the DV 500, which goes up to 500,000 V. In addition, the company added attachments for testing underground and elbow bushings.

Not long ago, the DV 100 and DV 500 were primarily used by troubleshooting crews. Today, the DV 100 and DV 500 are used as the single-point voltage indicators of choice for all field professionals, including linemen.

By partnering with HD Electric, ComEd has been able to improve its linemen’s productivity in the field and to protect them from accidental contact with live lines during storm restoration. The utility is always keeping its eye on new tools, and as a result, the company has been able to improve efficiency and minimize injuries in the field.

Edward Bengson ([email protected]) is a senior specialist in ComEd’s methods department, where he works on finding tools that make linemen safer and more productive.

Companies mentioned:

Commonwealth Edison | www.comed.com

HD Electric Co. | www.hdelectriccompany.com






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