In the recent article, we read about the sources of surges in Industrial & Commercial Power Systems. In this article, we will analyse solutions to protect the electronic equipment from surges. Nowadays, many electronic equipment failures are mainly due to two main reasons mentioned below.
With availability of online harmonic analysers, it is made simple to study harmonics, which comes under AC Power quality. Once you find solution for harmonics but still the problem remains and equipment failure continues due to unknown reasons, then it is mainly attributed towards surges. Surges can be lightning surges and switching surges.
There are two types of lightning surges: radiated and conducted.
Surge protection devices, such as Faraday Cages, can reduce radiated surges, while SPDs, or Surge Protection Devices, and can reduce conducted surges that flow through power, data, and communication cables.
SPD will only conduct under surge situations, remaining in sleep mode or performing no function similar to a fuse within its presents rating during normal conditions.
A FUSE is a current-operated device connected in series with the load in most power line applications, while SPD is a voltage-operated device connected in parallel with the load. SPD can be drawn numerous times, depending on how much surge SPD absorbs over time.
Surge or over voltage exists only for few microseconds to few milliseconds and hence the total energy is not huge. SPD operates when the voltage across it exceeds a pre- determined level called MCOV- Maximum Continuous Operating Voltage.
Not just the selection of SPD for a particular application is needed, but its installation is also much more crucial. Improper installation can damage both the equipment and SPD. In some cases, equipment continues to fail while SPD is in good condition. Both are undesirable situations. In addition, most of the Electrical Engineers are well versed in the installation of fuses, MCBs, etc., that are current operated devices whereas SPD is a voltage-operated device, in which a short, straight run of wire is more important than the thickness of the wire.
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