9/2/15 Where Does It Come From?

The August malaise, having passed with its sweltering oppression, has me recovering my words and ready to write, or at least anxious to start back writing.

NM1Have you ever wondered just what happens when you flip the light switch at your home? What do you expect when you do? How do you feel when the expected does not occur?

I am a bit weary early this morning and not willing to write an entire treatise on just what monumental efforts are required so the expected thing happens when you flip your switch, but I am going to give you a glimpse of an urgent and extremely important part of that process: your nearby electrical substation. Having said that, let me go on to say that every part of the process must work correctly in its time and place, else the light will not shine. Each step further back up the source affects exponentially greater numbers of people and their activities.

NM3Substations are where long-distance transmission voltage power is stepped down into what is called distribution power, which is the power carried on the lines that reach your home, your school, your plant, or your office. If you look outside and see an overhead power line, its source is probably your closest electrical substation; if you don’t see a power line, it is underground but still has the same source. If you have no underground or overhead power line at your home, then you are off the grid and are viewing this through an elaborate system you have installed, or you are somewhere besides at your home, since none of this will work without electricity and you must be connected in some manner.

Substations don’t just spring up without some serious planning, expense, and hard work. Keeping them maintained and operating is a constant vigil. Talented and dedicated people plan and design them and their specific operational functions and protective schemes, and yet other talented and dedicated people operate and maintain them on a daily basis. We build them.

It takes years of planning and hard work to get to the point of flipping the switch and “turning on” the substation in exacNM4tly the way you flip the wall switch for the lights over your dining room table but the devices in your home are much smaller, since the voltages are much lower and the load, the connected devices that consume the power, is much lighter. Once flowing, electricity wants to continue to flow, so a load interrupting device is required to safely switch it off. The bigger the load, the more robust the device.

There are several predictable factors that influence this, such as available fault current, which does not interest the person flipping the switch in his dining room, but is of intense and immediate interest to the engineers designing the substation and those who operate and maintain it and the transmission line that feeds it and the distribution lines it feeds. I could go on for days, and have friends and colleagues who are design engineers I respect and admire who can yet teach me more than I already know. Like you and your wall switch, it’s not important that I know everything, nor is it prudent for me to think I know everything. What’s important is for me to know what I am supposed to be doing….and I do….I most surely do.

Building a substation is a glorious thing to me, though it is not easy. Life is filled with things that only come with great effort, through great obstacles, which only perseverance and determination will see through to the end: in this case, the flipping of the switch with the desired result. Starting out with a site that seemed below sea-nm5level, under a ten acre canopy of huge hardwood trees that Spanish explorer Hernando DeSoto himself must have made camp under as he passed through modern day Marshall County, Mississippi, making his way onward to the modern day Desoto county named for for him as he prepared to meet the father of waters for the first time….through rain, mud, freezing days and nights, sweltering summer heat, thunderstorms, lightning, and wind, scores of subcontractors and men all needing sometimes moment-by-moment direction and guidance, inspection and adjustment of key components furnished by vendors who seem have shipped you items they started assembling on Friday before a long holiday weekend and then completed in the throes of a Tuesday morning hangover…equipment that breaks down, more mud, more cold, more heat, and then again more mud. Did I mention the mud?

Then, the mud is gone. You are out of the mud, and the substation arises out of the ground as if by magic, arising overnight to the astonishment of passers-by who say to themselves, “They sure have put that up in a hurry,” though they are only seeing its steel framework, not the miles of ground wire and conduits in the ground, nor the hundreds of cubic yards of concrete and tons of reinforcing steel, all invisible, that it took months to install. The whole time this invisible work was going on, in the mud (there’s the mud again), those same passers-by wondered, “What are all those guys doing out there?”

Once the franm7me-work is up, the bus, the rigid, isolated, air-insulated conductors that carry the current is installed, then the dozens of switches, then the load-interrupting devices, then that most magic, efficient, and important part…the power transformer. After the transformer, then comes the individual circuit breakers, the voltage regulators, and all the relays and protective devices that operate and protect the equipment and the people who operate and maintain the system. These relays and logic schemes also help protect you and your home, just like the circuit breakers in your own power panel in your home. The annoyance of a tripped circuit breaker in your home, doing exactly the thing it was designed to do, is much less of an annoyance or inconvenience than a fire or an electrocution, which is a terrific understatement.

The power transformer, doing its job with no moving parts, efficiently, constantly, and reliably, is the device that the entire substation serves to support and protect. It is the very core and the reason for the substation; without the power transformer, the substation can do nothing. It is by a wide margin the single most expensive and massive part of the substation. A 25MVA (mega-volt-amp) transformer is not even a particularly large one, but they can easily cost half-a-million dollars or more, depending on their specification, and serve for 25 to 40 years, or longer, without so much as a blink, though if things go wrong this mass of copper, steel, and insulating oil can light up the night sky like a Saturn rNM2ocket and launch parts of itself into low-earth orbit just as fast.

I have written about this before, but it bears repeating.

After months of work, the magic moment arrives when it is time to flip the switch. The plan is for this to be uneventful since in our business, an “event” is a particularly undesirable thing. An “event” is an abhorrent thing. An “event” is loathed and despised above all things. Literally hundreds of people have worked diligently to make sure that what you see in the video below, uninspiring and pointless to some, was as uneventful as it was. The video might seem boring to you….but it is anything but boring to me. It is the culmination of months (years actually) of work by the owner, the design engineers, the general contractor (that would be us), earth and concrete contractors, environmental contractors, the power transmitter and supplier (TVA), the steel fabricator and packager, the many vendors furnishing switches, controls, cables, and other devices, down to the stores and local vendors where we purchased meals, lodging, and incidentals, and all of their employees. Everyone had a hand in the boring video below, allowing me to show you, the most desirable thing of all, the magic of an uneventful flipping of the switch.

Uneventful! My, oh, my…..after that, I sure could enjoy a cigarette.

Many thanks to you all.

Note: In the video, the big thing in the middle is the power transformer. The tall thing on the left, like three huge candles in a steel candelabra, is called a circuit switcher. It is a load interrupting device, similar to the main-breaker in your house power panel. It operates at 161,000 volts and will interrupt a tremendous load. The “WHAM” is the circuit switcher swiftly closing its internal contact parts, picking up only the charging current of the power transformer. The “Rrrrrrrrrrrrrrmmmmmmmmm” hum is the transformer itself, now energized. The “gittchy-gittchy-gittchy” sound is the circuit switcher re-arming itself for another operation should it be called on. All this? Uneventful.

The entire job? No recordable injuries. I did cut myself, small nicks and scrapes, more than once. My son, Canaan, would typically remark, almost daily, “Dad, you’re bleeding, again,” with me not having noticed. In spite of that, I never missed any work, nor needed anything more than a band-aid, with some judicious use of super-glue a couple of times. I did get stung eight times when attacked by guinea wasps which had built a nest in the cab of a piece of equipment that had been idle for several weeks, but that only resulted in immediate but short-lived pain and a long string of the most colorful expletives as I out-ran them after out initial encounter, of which they seemed to have upper hand, the element of surprise being on their side. I, though, had the last word in the overall exchange after having fared poorly in the first battle; unlike the wasps, I am still here. 🙂

In a word….thankful!

My brother and my son were rocks of support when the sands (mud, really) seemed to shift under my feet, as were Larry, Barry, Tom and Ed.

©2015 Mississippi Chris Sharp

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