A modern metropolis can not exist without electricity, and It powers most urban objects – from large industrial enterprises to public transportation, which in turn all generate significant amounts of electromagnetic radiation. Today the concentration and intensity of electromagnetic waves in cities where the population exceeds millions of people can lead to numerous, unpredictable technical malfunctions with electronic devices, disrupting work. Issues with automated electric trains, traffic control systems, banking systems, medical equipment, utility systems, in general, any device where electromagnetic waves can cause malfunctions. This phenomenon called radio frequency interference (RFI) or electromagnetic interference (EMI).
The effects of RFI has been know since the emergence of radio engineering, but since we become so dependent on electricity, we have become vulnerable to issues with electronic devices caused by RFI.
Essentially RFI is generated while powerful electronic devices operated, and the sources of which are quite often arbitrarily and randomly distributed in an urban space.
As experts say, the main source of interference is sparking that happens mostly when an electric circuit breaker is operated, causing sudden changes in the electric current. Unshielded overhead power lines can act as an antenna thus both generating and affected by RFI. Radio frequency interference can be impulsive and disruptive for telemechanical devices through antennas, power circuits, capacitive and inductive couplings. An other source of interference can be the metallic conduit of wires where the earth is used as grounding, the voltage in which arises from roaming ground currents. In dry regions interference often caused by air turbulence and high solar radiation as well. The interference level rises sharply when the transmission lines are faulty. Magnetic fields, radio emission and metal, which present all over in every city, only strengthen the effects of these spontaneous signals and the distance to which they propagate can reach to tens of meters.
The effects of RFI also stronger when telecommunications equipment closer their source and potentially can cause greater damage. Of course, modern electronic devices equipped with protection against such signals, but some interference effects appear in the same spectrum of frequencies where our devices operate. Automated control systems can be especially vulnerable when interference occurs at operating frequencies as it disrupts the transmitted information which in turn can not be processed and the equipment stops working or malfunctions. An example for this is when car keys won’t open or lock the vehicle remotely as the signal or information disrupted as it happened in one of the central regions of Kiev. Cars simply stop responding to the key fobs and can be opened only with the key, which nevertheless does not guarantee that It can start up as most cars equipped with additional security devices. Some car owners push their cars some 50 metres or so just out of the “dead zone”. There are often similar cases in industrial zones of other large cities.
The problems can only be of any concern when it comes to large amount of customers and users. This applies to either metallurgic entreprises that use huge inductive industrial furnaces for metal melting, or other high voltage sources for the purposes of electromagnetic effect. Those can be radio stations or some navigation systems, or even airports”, – says Alexander Repkin, the chairman of the advisory committee of “Tokmak Solar Energy”, energy expert.
RFI related issues can appear in all areas, disrupting work from secure banking systems to mass transportation. In some cases, it can even lead to a fire, as it happened a few years ago in Warsaw, on a new German built train. Experts investigating the incident couldn’t rule out the possibility that RFI caused the electric motor to overheat.
The reasons of the technical disruptions in equipment operation, similar to those mentioned earlier, were also expressed by Hungarian engineers while their investigation of the failures with doors and panto-graphs 10 years ago. Interestingly enough, that the trams were also German-made.
Electronic medical equipment is especially sensitive to radio frequency interference. For example, people who need to use pacemakers receive a list of strict recommendations to avoid certain devices, such as mobile phones should not be operated closer than 15 centimetres to the pacemaker device, where possible avoid security gates, etc. – in this case, RFI can lead to death.
Another victim of RFI is cellular communication networks. Interference caused by power lines, industrial enterprises, neon advertising, car ignition systems, computers, etc. In case the interference level is high it’s becoming increasingly difficult to use mobile networks. Intense RFI presence is the reason of “failure” of communication systems in those areas of Kiev, where, it would seem, everything should be normal.
According to Alexander Repkin, the cause of such failures should also be controlled by Ukrchastotnaglyad.
„The Ukranian electircal chain is in the impulse of 50 hertz. The rest of equipment is operated at 40-50 hertz. It is in this regard that arouse issues with mobile networks or inability to deactivate the alarm, or any other signal bleeds. Those are uncontrolled radiation sources with more than 2 Watt capacity. It is these sources that need to be controlled at the state level, ” – the expert believes.
A study made in Japan has shown that more than 50% of robot incidents (capable of operating by itself with minimal human interaction) caused by radio frequency interference within the control system.
photo: smartclever.com.ua
