Mind Your Safety

Entering Outdoor Substations, Part 2 of 8

Look for other workers. If you see vehicles inside and work is going on, then perhaps you don’t need to be there. No one ever plans an accident, and many accidents happen because of human intervention... so if humans are already in there intervening, why be there if you don’t have to?

To be in an outdoor substation, you must understand the dangers of induction. When you do not understand electrostatic and electromagnetic induction, you are not qualified to enter a substation. The system is continuously trying to energize everything metallic for as far away as it can. One of our Ohio farmer students parked his combine under a high line and, when he went to grab the rail to step in the next morning, he said the electrostatic inductive discharge flattened him.

A western utility lost a senior lineman several years ago when grounds installed the afternoon prior had current induced on them electromagnetically by the next morning. Even though he had remarked on several tingles, a direct contact electrocuted him.

I have an excellent video from a client’s site showing electrostatic induction on an unused messenger line attached from an insulator inside their substation to an insulator 7 feet up on the eaves of their administration building outside the substation. I had 21 electricians, including the supervisor, in absolute amazement at my tic tester beeping 18 in. away from this unused line they had all been walking under for years. Be very aware of induction: it’s deadly, but hard to recognize potential instances of it.  Tingling is only one clue.

Do a closer visual inspection, especially at the transformer insulators, for any signs of loose connections, heating or any other noticeable problems. When you are experienced in substations, you turn on your gut: it is well proved that our gut is part of our radar system and, when something doesn’t feel right in our gut, then it may very well not be. Evolved over millennia, your gut instinct is your early warning system. Listen to it.

Look for lines that are going into the substation and connecting to insulators but are isolated. A particular client’s substation was de-energized, and two workers went up the substructure to work; when they completed their work, the first worker retraced the path he came up. The second worker, thinking he would take a shortcut, came down the side of the substructure, and stepped onto an insulator on the side of the structure. The cable feeding into this insulator was dead-ended, yet still energized, and nobody had realized it during the lockout procedure. The resulting electrocution and fall were fatal. So, choose your path in carefully, and follow your steps out exactly as you came in.

Stay away from equipment and lines. If you don’t have to walk under any lines, don’t. If you do, walk exactly in the centre of all substructure equipment and not under any of the lines. If you are following an experienced worker and they are not following this practice, then follow exactly behind them. They may want you beside them to discuss things but, if they don’t, follow behind them by 10 to 15 paces. Use them as a voltmeter; if there is a problem, they’ll encounter it first.

But know this: should a problem arise, you will be unable to help. However, it is incredibly rare for problems to occur in a well-maintained substation. Should an accident occur, retrace your steps exactly, keeping your feet close together.

Until next time, be ready, be careful and be safe.