Undervoltage in the network, how it will affect the meter readings

Hello everyone who came to my channel and decided to read this article. In today's article, I want to tell you what will be primarily affected by a not very pleasant moment like undervoltage in your home network. So, let's begin.

First of all, I want to rather briefly go over the electricity metering algorithm. And I want to start with the time-tested disk counters, which probably still remain in the shields of many of us.

So, in a disk-type electric meter there is a pair of coils:

1. Current. It is easy to distinguish it from a voltage coil, since it is implemented with a thick single-core copper wire. It is included in the chain in a sequential manner.

2. Voltage coil. It is realized with a thin copper wire and connected in parallel in a chain.

Moreover, these two coils are positioned relative to each other at an angle of 90 degrees.

An aluminum disc is placed between the coils. When the meter is turned on, an electric current begins to flow through it. Also, due to the electromagnetic effect of the current coil and the voltage coil, induced eddy currents occur in the aluminum disk.

And further interaction of eddy currents with an electromagnetic field makes the aluminum disk rotate. Thus, the electricity consumed by you is counted.

Digital electricity meters differ from old meters in that they are undergoing a transformation process analog signals into pulses, which are then sent to the microcontroller, where they occur count. And the display shows all the information.

So, as you already understood, parameters such as current and voltage are important for the calculation. Well, now let's figure out what effect the undervoltage has on the readings of the electricity meter.

How the load behaves at reduced voltage

According to GOST 29322-2014, our sockets should have a voltage equal to 230 V, and the permissible long deviation allows up to 5%, and in the short term a deviation of 10% (up or down) is allowed.

Now there will be a little simple and boring calculations, but they are very important for understanding the essence.

So, let's say the voltage in the network is equal to the prescribed 230 V, and you decided to drink hot tea. And for this they turned on an electric kettle with a capacity of 2 kW. If we apply the following formula: I = P / V, then we will find out that the current consumption of the kettle will be equal to 8.7A. But this formula will in no way help us know what will happen to consumption when the voltage changes.

But, as they say, no one canceled Ohm's law and, according to it, the current is directly proportional to the voltage and inversely proportional to the resistance: I = U / R.

So, we are considering with you the case of the teapot. You and I became aware of the current from the above calculation, now we will find the resistance of the spiral from Ohm's law by simple transformations: R = U / I and it turns out R = 230 / 8.7 = 26.44 ohms.

So, you and I know that the current depends on the resistance, which in our case is constant and the voltage, which just dropped.

Let's say you measured the voltage, and its value was 200 volts. What will happen to the consumption of the kettle?

And it turns out that our kettle will consume I = 200 / 26.44 = 7.56 Ampere. And it turns out that the power of the kettle in this case will be P = 200 * 7.56 = 1.512 kW.

From this it follows that, in spite of the fact that our tension "subsided" with you, this practically will not affect the readings of the device directly. Yes, the kettle will take longer to heat up, and the counter will count longer, but at the same time less current.

This will be reflected indirectly. After all, you and I do not like to wait, and if we have low voltage on an ongoing basis, then in order to heat the kettle, we will need to buy a more powerful one. Well, to make the room brighter, we will install more powerful lamps. And this is exactly what will be reflected. After all, we will increase our load, which means that in the end we will pay more for light.

Attention. With this calculation, thermal dissipation is not taken into account, which, of course, will affect the readings of the meter, but insignificantly.

It turns out that the metering device at a reduced voltage will not wind up extra kilowatt * hours, but if it (voltage) below the limits indicated in GOST, then you should complain to the appropriate authorities in order for this situation to be corrected.

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