Keeping the wheels of industry turning… some more…
Back out at a client facility today, installing new system protection equipment, commonly termed “relays”, actually a whole new panel full of them, products of the march of technology.
From the beginnings of the electrical power business, equipment had to be protected from faults, things happening which should not happen. Faults usually result from, or can cause damage to equipment.
A fault resulting from damage would be the outage caused when some winehead drives his Beemer into a utility pole and brings the wires down. When the wires hit each other or the ground, they allow a lot more current to flow, and this current flows in an improper path. It results in fires caused by the intense heat, and can cause damage to transformers and other equipment, so it needs to be stopped.
A protective relay is what makes the decision to stop it. For a hundred years little coils of wire and pieces of metal were carefully crafted and placed in circuits to sense the current flow, and if the current flow went past a certain amount for a certain period of time, the pieces worked to close a set of contacts and trip the circuit breaker through which the current was flowing. And when it did this, a flag dropped, a little piece of colored metal that indicated that THIS relay had operated. That was it. Three conductors left the substation, and you knew that somewhere between the substation here and whatever was on the other end, something on THAT wire was a problem. But sometimes TWO relays would operate, or even ALL THREE. You had just a little bit of data. With that data, you just started walking, or driving, or whatever, looking for the fault. Sometimes you could look up the street and see flashing lights at the scene of the accident. That was a help. But sometimes there was no help…
On very important circuits like the transmission lines which feed huge amounts of power from one area to another, the utility company would put an oscillograph which would start recording if a fault occurred, and from the oscillograph chart, and careful calculations, a fault could be located fairly close: no small comfort if you’re talking about seaching fifty miles of right-of-way over swamp for a faulted line.
Enter the microprocessor. Now it’s easy. What used to take dozens of components to accomplish, and being semi-mechanical in nature, was subject to many different failures itself, that’s all now taken care of by one neat little box. Hook a few wires to it, and the knowledge of the universe (or at least, parts of your power system) is at your fingertips. And if you don’t want to put your fingertips on it in person, you can talk to it from remote locations via data links, Ethernet over copper wire, fiber optic, or various radio devices.
There you go. Most people go about their lives not knowing a bit about how the electricity keeps getting into those little holes in the wall, or why sometimes it stops… Now you know a little bit more…