2024 Electrical circuits and receivers in hotel facilities.

pure capacitive circuit

• For its explanation, the ohmic resistance offered by the cables is not considered and only the effect caused by the capacitors.
• The sine wave is not distorted either in voltage or current.
• Passing the current through the capacitor causes a shift between the applied voltage and current.
• The sinusoidal component of the current is 90º in advance with respect to that of the applied voltage.
• When the instantaneous voltage is maximum, the current is 0.
• When the instantaneous voltage is 0, the current is maximum.

https://www.areatechnology.com/electricidad/circuitos-de-corriente-alterna.html

Circuit with nonlinear loads

• They are those that cause disturbances in the electrical network.
• As a consequence of these disturbances the wave ceases to be sinusoidal.
• Distortions caused by receptors are called harmonics.
• Harmonics are non-sinusoidal periodic functions.
• The Fourier theorem indicates that any non-sine periodic function can be represented as:
  • a sinusoidal term that is the fundamental frequency
  • harmonic sinusoidal terms

http://automata.cps.unizar.es/bibliotecaschneider/bt/guia/5_armonicos

At the top of the graph Real wave caused by the receiver

Next, the fundamental (in Europe 50 Hz.)

Then the decomposition according to Fourier in harmonics of order 3,5,7,9

Basics

1

In any electrical installation, the ideal is that the voltage and the current go in phase, with which the powers of generators and transformers are fully used.

Each receiver is manufactured for a power.

Power = Voltage * Current

Power is the work developed in the unit of time.

Energy = Power * Time

The cables offer resistance to the passage of electrical current. (R)

When the electrical current circulates through the cables, (i) losses occur due to Joule effect.

Power lost in the cable = V * i = (i * r) * i = r * i^2

These power losses in the cables are transformed into heat.

It is important to note that they are proportional to the square of the intensity.

In resistive receptors (pure ohmic resistance), all the intensity that circulates through the cable is necessary to produce work and therefore the energy losses in the cable are minimal.

In receivers equipped with coils such as motors, the intensity that circulates along the line is greater than that required by the receiver to develop its active power.

Therefore, the energy losses in the lines are higher than those strictly necessary.

The same thing happens in a capacitive circuit. Although capacitors are used in electrical networks to improve the power factor.

As with inductive currents, in circuits with non-linear loads, harmonics cause an increase in circulating intensity and an increase in power loss due to joule effect, with a series of complementary aggravating factors due to harmonic distortions, which cause deficiencies in the operation of the installation.