High temperatures cause conductors to expand and hence increase in length. The converse is true for low temperature conditions. The change in length varies from one conductor to another depending on its thermal expansivity. The length of copper conductors, for instance, changes by 5 feet per 1000 feet of length when the conductor temperature changes from 100 – 0°, while aluminum changes by about 7 feet. The length increases with increase in temperature and reduces with reduction in temperature.

This increase or decrease in length is of great concern when installing power transmission lines between poles and towers, or when installing other power connectors. There must be an allowance for this change in length since it can cause catastrophes if it’s not there.

Weather changes are associated with increase and decrease in temperature and thus affect power transmission lines and other conductors. However, change in temperature is only one factor that affects power lines. Below are the changes that occur to power lines and other conductors as a result of weather changes:

The amount of heat dissipated from power conductors is reduced during hot and calm weather conditions. Basically, if the temperature of air around the cable is low, more heat is lost from the cable to the air. If the air is already hot, the exchange of heat is lesser. This low heat dissipation causes the lines to overheat. However, the rise in conductor temperature (overheating) worsens when cables are transmitting too much power than required. The first effect of this increased conductor temperature is snagging, which is the downward bulging of the cable between two poles, caused by the increase in the length of cables.

Snagging is largest during extreme hot weather (largest increase in temperature) conditions experienced in summer. The increase in length results to downward bulging of the cable due to the effect of gravity. Excessive sagging is dangerous if it goes below the accepted height clearance – cables could come into contact with trees, buildings and other structures underneath, causing electrocution and fires.

Excessive sagging represent an added weight on the power line and this increase may cause the line to fail or to pull down weak poles and towers. The effects can be small but gradual and so the poles and towers will finally come down or require some adjustment/replacement after some time, which is costly. This sagging can also cause the lines to short out. Excessive sagging is also costly since it leads to increased electrical resistance. This means that a sagged power line transmits lesser current than it normally does, thus causing under-feeding of electrical equipment and industries. It is also costly and time consuming to rectify a sag.

We’re already nearing the end of May. It’s hard to believe, I know. It can be a little uncomfortable to think about how quickly time passes. I’m here to help with a reminder that time’s rapid passing only means all the cool things about each season will reach your senses sooner.

This is an especially exciting time of year, at least for me. By this time, I have been spending a lot more time outdoors. Finally, the pallid, morose visage of a long winter has been touched by a little sun. Exercise has my energy levels up, and it seems like every evening, I’m exclaiming as if for the first time, “Man, it’s NICE outside.”

You’re like, “Where is this going?”

I want to show you some pictures of bugs! Fireflies, in particular. Even more specifically, I want to show you some long exposure digital photography of fireflies. Why? Because it’s really cool. Who doesn’t like chasing fireflies with a camera?

If you are one of our beloved regular readers, you might remember my posts about via audobonmagazine.org

Pretty cool, huh?

Electrical motors are devices that convert electrical energy into mechanical force. They operate on the principles of electromagnetism, using the interaction between winding currents and magnetic fields to generate force. Some motors, like those used in the transportation industry can reverse the effect and generate electricity too, converting force into electricity.

Many industrial plants attribute over 70% of their power consumption to motors, so even a slight increase in efficiency can dramatically cut energy spending and improve profits too.

The London Olympics are certainly on the tip of nearly everyone’s tongue (and Courtesy of FrenchArt-Deco.com

This piece, entitled “Swimming Pool” by French artist Albert Decaris won gold in the Engravings and Etchings competition.

In 1949, the International Olympic Committee decided to stop all art competitions, reasoning that it was illogical to let professional artists compete, while only amateur athletes were eligible. Instead, cultural festivals replaced the art competitions, and still do to this day. There’s still a chance for the best of the best artists and entertainers to showcase their stuff on an international stage, and for lighting designers, this is certainly a world class exhibition. 

LED is the light source that’s in it to win it this summer, wowing Olympic fans with spectacular light shows and festive monuments alike.

At the opening ceremony, LEDs were at the center of almost everything. The dove bikes used LEDs to light up their wings as they performed a circuit of the stadium.

LEDs lit the screen showing the Queen’s acting debut, with none other than James Bond.

Even on the sidewalk outside the main Olympic Stadium, there are 20 circular slabs that capture the kinetic energy of pedestrians’ footsteps to light up nearby LED lamps for 30 seconds at a time!