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With power electronics, high voltage dc systems are available which
greatly decrease losses over long transmission lines. The ac generated
power is increased to very high voltages, rectified and transmitted
via a dc line and converted back to ac using inverters where it can be
transformed to any required voltage.
With very high dc voltages corona discharge becomes a problem
and the losses can offset the advantag-
es. Steps can be taken to reduce
the corona losses.
Illumination
We have progressed from sunlight and fire to candles to gas, arc,
incandescent and fluorescent lamps and now to LED lighting systems.
LED lighting saves power. It is expensive to install initially but costs
have come down and, as time goes by, they will come down further.
The life expectancy for these lamps is long and power savings large.
Conclusion
Looking to the future, generation of power is an area where the envi-
ronment is negatively affected if we continue with the old coal fired
boiler power stations. Yes, there is pollution control on these systems,
but it does not solve the problem.
Efficiency of motors and transformers is moving forward but it can-
not be looked at in isolation. The entire systemmust be considered. It
serves no purpose to use a premium efficiency motor in an application
where the motor runs on no – or very light – loads for 50 or 60% of the
time; an alternate solution must be found. In distribution transformers
that are loaded for short periods, iron losses become very important.
Evaluate loads using a systems approach. A piece of equipment
in isolation is not effective and the application and system must be
considered.
New materials are being developed but the challenge is how to
best use these materials in the machines.
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ENERGY EFFICIENCY MADE SIMPLE 2015