Several factors may cause AC voltage variations. These include Switched sources, Ripple, Noise, and Pole-to-neutral faults. However, it is essential to note that these variations will not harm your appliances. You can avoid them by taking the proper precautions. These tips can help minimize the risks associated with AC voltage variations.
Switched sources
AC voltage is the difference between the potentials at an alternating current’s positive and negative terminal (AC). It has the shape of a sine wave. It begins at zero, reaches a peak, and then falls back down. It is usually expressed as V pp, V P-P, or V_textpeak.
AC is the most common type of current in buildings. It is easier to generate and transport than DC electricity. Higher voltages reduce the amount of energy lost in the power line and the amount of heat generated. But lower voltages also reduce the heat emitted from the power lines.
Noise
AC voltage variations can cause noise to an electrical system. The noise of this type occurs in two distinct ways. The first type is called common-mode noise, which appears on both sides of the line as both lines are active. The second type is transverse-mode noise, measured between two active conductors. An external disturbance often generates common-mode noise.
AC voltage variations can produce a wide range of noise. Impulse noise is produced by transient electrical activity, including electric motors and telephone exchanges. It swamps the desired signal and corrupts data bits. This makes it difficult to decipher a message. A technique called cyclic redundancy checking can detect this type of noise.
Ripple
The ripple effect is a phenomenon caused by variations in the alternating current in an electrical circuit. The ripple voltage is typically small compared to the DC component but can reach thousands of volts. The ripple itself is a no-sinusoidal waveform, and its frequency is usually the same as the original AC line frequency, which can range from tens of kilohertz to several megahertz in switched-mode power supplies.
The ripple effect of AC voltage variations is often confused with noise, and undesirable electronic interference. Although both are similar, they have different causes. Noise can occur due to switching and electronic noise generated outside of the power supply. It is particularly undesirable because it occurs at high frequencies and is unpredictable.
Pole-to-neutral faults
Pole-to-neutral faults in the AC voltage variations of electric appliances are often complicated to detect. However, they can be accompanied by flickering lights or tingling taps. The resulting power failure can be fatal or cause serious injury if not addressed. Ideally, the voltage between neutral and ground should be two volts or less. Any more than this is considered an overload. However, in some cases, this can be up to 5 volts, which is still very dangerous.
The neutral conductor (or neutral current) is an essential circuit component in a three-phase system. Its role is to complete the circuit from the source to the load. It is usually connected to the ground at the main electrical panel, the street drop, the meter, and the final step-down transformer. When the neutral conductor is intact, it carries the residual current to the supply, which helps prevent unstable system conditions and dangerous voltages.
Nonlinear contribution to current
AC voltage variations cause a nonlinear contribution to the current flowing through a load. This is due to the waveform distortion a nonlinear load creates. This distortion comes from a DC offset, harmonics, and electric noise. These disturbances come from the power source, but they also come from nonlinear loads like electronic equipment. These nonlinear loads generate harmonics and voltage spikes, damaging the power system and cause equipment to overheat.
Because a nonlinear load creates voltage and current distortions, it pollutes the AC power system. A nonlinear pack can overheat if it is not adequately controlled. Therefore, it is vital to use equipment and installations with low impedance.
Overvoltage protection
Overvoltage protection circuits are useful devices to prevent power supply damage due to voltage variations. They are designed to display an LED that indicates when overvoltage or under voltage is detected. They are easy to install and implement. If unsure how to create a circuit, you can ask an electronics professional for assistance.
There are several overvoltage protection circuits, each with a different purpose. Some are used for protecting electronic assemblies with regulated DC power supplies. Others are designed for protecting electrical equipment against mains over-voltage caused by supply network disturbances. Protection circuits should generally shut down the power supply and divert any excess voltage to a capacitor. They should also be able to differentiate between overvoltage and normal voltage fluctuations. Moreover, they should be fast enough to shut down a power supply if an over-voltage condition occurs.
