What is induced voltage and what is its danger
Dec 31, 2020
Induced voltage on overhead power lines and associated electrical installations is much more dangerous than operating voltage. And in the home network, the manifestation of induced voltage is also possible.
In this article, I want to talk about what a "targeting" is and how this phenomenon is being fought.
What are the reasons for the induced voltage
Induced voltage is formed on a power line that is disconnected or taken out for repair due to the impact exerted on it by another power line running in parallel that remains energized.
And the formed potential poses a real threat to the personnel who serve this power transmission line.
In this case, the amount of "aiming" depends on:
- The length of the section where the two lines run parallel.
- From what voltage is on the line remaining in the work.
- Ambient conditions.
- Current strength and distance between wires of adjacent lines.
At the same time, the formed potential contains two types of influence at once: electromagnetic and electrostatic.
- The electromagnetic part is formed due to the action of the magnetic field formed in the course of the current flowing through the power lines remaining in operation. The main feature is that no matter how many groundings you put on a disconnected power line, the electromagnetic component will remain unchanged. And with grounding you can only change the zero point of the potential and no more.
- Electrostatic component. Unlike the electromagnetic component, this component is leveled by installing grounding at the ends of the line and directly at the place of repair and restoration work. Even the installation of one grounding system significantly reduces the electrostatic component.
Let's take a close look at the following photo:
The photo shows the conductor AA. During the flow of an alternating current along the conductor, an electromagnetic field is formed around, the intensity of which gradually fades away from the conductor. So, by placing another conductor in the area affected by the electromagnetic field, an induced voltage is necessarily induced in it.
Moreover, if the value of the induced voltage does not exceed 25 Volts, then additional protective measures are not required for repair work. If the induced voltage is more than 25 Volts, then a whole a number of additional measures: additional grounding of the workplace on both sides, wire cut, etc. P.
Why is induced voltage so dangerous?
The most important danger of "pointing" is that if a person falls under its influence, then the protective the equipment will not react in any way, and the person will be energized until it is de-energized manually.
Note. By the way, if a short circuit occurs on a nearby line that remains energized, then at that moment in the line, it was removed from operation, the induced voltage was not more than 25 Volts, it will be under the induced potential much more than the threshold value. And if at that moment repair personnel worked on a de-energized line, then people can receive significant damage.
Therefore, the most important thing is the strictest adherence to absolutely all safety requirements and strict adherence to the PPR.
Induced voltage in the home network
But do not think that "pointing" is found only on overhead lines. Induced voltage can also be encountered in your apartment or house.
The supply wires in the home network are always laid in a rather dense bundle, and this inevitably leads to "pointing". And if, for example, on the lighting line through the switch you have a zero break, and not a phase, then the induced voltage in this line will be quite enough for the LEDs in the lamp to start a little shine.
To get rid of this is quite simple, just put a phase on the breaker on the switch. And the LEDs will stop glowing.
Since the pointing can have rather dangerous values, especially on overhead lines or in existing electrical installations, the following protection measures must be taken for safety:
1. Apply voltage alarms.
2. Ensure an acceptable voltage level by installing additional grounding and other measures.
3. It is imperative to use specialized clothing, dielectric rugs, etc.
4. Be sure to use electrical insulating rods, voltage indicators to control and monitor the magnitude of the induced voltage.
Induced voltage is almost everywhere and if it is higher than 25 Volts, then special measures must be taken to ensure the safety of working personnel.
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