Power quality is the ability of the electricity supply company to provide the networks and their consumers with optimal service without interruptions, surges, erratic equipment operations, voltage variations and deformations caused by harmonics in the network.
Types of Disturbances
In practice, electrical networks present a series of alterations or disturbances that alter the quality of the service, among which the following stand out:
- Power Interruptions
- Voltage depression (SAG)
- Voltage dilation (SWELL)
- Peak Voltage
- Electromagnetic interference
How can you evaluate the Quality of Electric Power?
In order to evaluate the quality of electrical energy, it is necessary to use complex, precise and high-resolution electrical measurement analyzers.
The advantage of having an electrical measurement analyzer that stores information before and after an event is that later it is possible to analyze in detail all the measured variables and reach relevant conclusions that generate solutions to prevent some events.
What are Harmonics?
In power systems, harmonics are a mathematical way of interpreting periodic distortion in the waveform of voltage and current.
Harmonics are defined as sinusoidal voltages or currents with frequencies that are integral multiples of the fundamental or supply frequency.
They are generally not produced by the energy company, they are rather generated by consumers as industrial loads and if these harmonics are of sufficient magnitude, they can move towards the power system and affect other consumers.
- They lower the power factor.
- Overvoltage’s in the capacitors.
- They increase the RMS value of the current and / or voltage.
- They produce measurement errors.
- Malfunction of protections.
- Damage to insulation.
- Decrease in the useful life of the equipment.
- They increase losses in motors, transformers and conductors due to overheating.
- Excessive currents in neutral.
- In the presence of capacitors, they produce series and / or parallel resonance.
Harmonic Producing Equipment
- Transformer saturation.
- Rotating machines.
- Electric and induction arc furnaces.
- Static power converters.
- Rectifiers (Battery chargers).
- Static reactive power compensators (Facts).
- Fluorescent lamps (with electronic ballast).
Harmonic reduction techniques
- Know the design of the power system.
- In-line inductance (AC).
- DC controlled inductances.
- Rectifiers of 12, 18, etc.
- Tuned filters (for 5th, 7th, 13th harmonics…) / detuned.
- Active filters.
- Neutralization transformers.