Linemen can learn about bonding and grounding techniques by reading books, watching PowerPoint presentations, participating in classroom discussions and on-the-job training. Now a new simulator built by a SaskPower lineman offers SaskPower’s field workforce a hands-on approach to learning.
SaskPower is currently revising its bonding and grounding training, and needed a visual to train its crews. Rather than working on another slide show, Quinn Dubnick, a live-line methods training coordinator and journeyman lineman for SaskPower, took his own initiative to design and build a parallel line induction simulator in his home garage to help demonstrate some of the principles and theories.
The interactive display sits on a 10-ft mobile table and encompasses both a three-phase and a single-phase line with various structure models. To emulate the real world, the three-phase wood poles are made of a semi-conductive material, as is the model for the earth, says Jay Beattie, a senior high-voltage and power systems engineer for the Technical Services and Research Department of SaskPower.
"Just as airplane pilots both fly real airplanes and practice on flight simulators, linemen can use this tool in a hands-on mode," Beattie says. "This simulator is a valuable addition to SaskPower’s training resources — an effective learning instrument. By playing out actual work procedures and seeing how to ameliorate potentially lethal hazards, our crews will be safer."
By training the field crews on the simulators, SaskPower can raise awareness of the hazards associated with parallel line electrostatic and magnetic induction, which can be encountered during high-voltage work procedures, Beattie says. For example, to demonstrate body currents, doll figures were outfitted with LED lights — with one for step and touch potentials encountered on the ground, and another as a climber on a pole.
"By setting up various scenarios that are potentially dangerous on structures and on the ground, Quinn shows how creating an equipotential zone eliminates the hazard and that multiple grounds do not make things safer," Beattie says. "For this, he makes use of jumpers, pole bands, ground electrodes and a bond mat."
Kevin Schwing, director of health and safety for SaskPower, says the demonstration teaches crews how to bond properly to both steel structures and wood poles, and how to use the proper jumpers to make the body at the same potential as the work zone.
"It’s innovative and a great visual," Schwing says. "It helps the staff understand induction and how it works as well as the proper bonding and grounding techniques."
The table is set up with a transmission line and a single-phase distribution line. As such, it can demonstrate how much induction goes to the single-phase line. In addition, it can show crews how to create different circulating current scenarios by placing multiple grounds along a section of line. It also shows what happens if there is a downed line or step potential hazards exist around ground points.
In this situation, a bond mat can provide protection to the linemen.
"The display is energized, and if any of the figures light up, it shows that bonding techniques weren’t applied correctly," Schwing says. "It illustrates how to do things properly if the line is up in the air or on the ground."
In the past, SaskPower employees have set up scenarios to illustrate induction out in the field. The challenge with this approach, however, was that the utility had to bring all of its crews to that particular location.
So far, a number of field personnel have seen the demo and walked through several different scenarios at one of the larger service centers in Sasketoon in Saskatchewan, Canada. Because of the interactive nature of the simulator, the trainer can ask the linemen what they are having problems with and then answer their questions. Schwing remembers that when he showed induction in one particular moment, there was an "aha" moment amongst the crew members.
"Induction is an invisible killer in our industry, and the crew couldn’t believe it when the simulator illustrated it," Schwing says. "They stopped and took notice right away. We have been discussing it for a long time, but when they saw the LED lights go off, they got to see why they have to do what they are doing to stay safe."
SaskPower plans to take the prototype and develop it into a hands-on simulator to train employees on the principles of bonding and grounding. The utility can then use the simulator to educate the distribution crews and crew foremen, and demonstrate at its Safety Days.
Schwing says in the future, the display will become a big part of the utility’s training program on bonding and grounding. "We are going to expand and use it as part of our discussions to illustrate how to do things properly and safely," Schwing says. ♦