Electricity is perhaps one of the greatest inventions of modern times just as fire was that of ancient times. We are so used to using electricity and it has such a deep effect on our lives that we literally take it for granted. Whenever we need to use electricity, we simply throw a switch in the ON position without ever bothering that exactly how does this magic vibration get across to us from where it is actually generated. The journey of electricity from the power station to your home is really an interesting and exciting one. It falls under the purview of electrical power system studies and includes power transmission as well as distribution, which we shall study in detail as well progress in this journey.
Electric Transmission and Distribution
Even if you don’t know much about the technicalities involved in transmission and distribution, I am sure we have all seen huge transmission lines whenever we are cruising leisurely across the road in your car. Just see the adjacent picture to know what I am talking about. These towers are but a part of the entire network of equipment and paraphernalia which are used to transport bulk electrical energy from the power house to the final consumer point.
Basically the above process consists of two different parts. The process of transporting the power from the generating station to the sub-station comes under transmission, while the process of distribution of power from the sub-station to individual consumers comes under power distribution. Hence you can see that they are both extensions of the same process. Do not worry if you do not fully understand the various terms and equipments mentioned here for we will be dealing with them in detail in our later articles.
Basic Supply System Setup
Electricity mainly comes in two forms namely alternating current and direct current. Each of these has their own distinct uses. We will study about the transmission and distribution of both these types of current. Yet there are a few basic concepts which hold true for either of them and these have been defined as follows.
Since power is a precious and scarce resource, it must be ensured that the losses in the transmission and distribution system are kept to a minimum level. Of course some losses are unavoidable since it is not possible to have a totally loss-free transmission.
Since cost of power generation, transmission and distribution are passed on to the consumers; it should be ensured that the techniques and materials used for transmission are not overly expensive so that electricity costs are maintained within reasonable levels.
Transmission lines pass through various locations including roadsides, fields and so forth. There are human beings at most of these places and their safety from high voltages should be ensured by keeping the system at optimum insulation level.
The current in the transmission system should be maintained within reasonable levels since heat produced is proportional to current and it could result in overheating of the conductors apart from increasing power loss.
A schematic of a simple transmission/distribution system is shown in the adjoining figure which clearly shows the various steps involved transferring power from generation point to the point where it finally gets consumed. The main components such as generators, transformers and grounding are shown which will be discussed at later stages.
In our next article we will study about overhead and underground transmission systems and other aspects of power distribution.
Images from Living on Earth Website