Summary
IEEE 519 is a key standard for harmonic control in electrical power systems. It is especially relevant in installations with drives, UPS, rectifiers, chargers, solar inverters and BESS.
What are harmonics
In an ideal system, the voltage and current have a sinusoidal shape. In real systems, especially with power electronics, the waveform can be deformed.
Harmonics are frequency components that are multiples of the fundamental. In a 50 Hz system, for example, the fifth harmonic is at 250 Hz and the seventh at 350 Hz.
Harmonic sources
The main sources are non-linear loads, such as:
- Frequency drives.
- UPS.
- Rectifiers.
- Battery chargers.
- Electric ovens.
- Welders.
- Electronic lighting.
- Solar inverters.
- BESS.
- Industrial electronic equipment.
What is THD
THD means Total Harmonic Distortion, or total harmonic distortion. It can be applied to voltage or current. It expresses as a percentage how much a signal has been distorted with respect to its fundamental component.
A high voltage THD may indicate that the power quality in a bus is affected. A high current THD may indicate that a load is injecting relevant harmonics.
What is TDD
TDD means Total Demand Distortion. It is especially used to evaluate current distortion in relation to a base demand current.
The difference between THD and TDD is important. A small current with high THD does not necessarily represent a major problem for the network. Therefore, the evaluation criteria consider the magnitude of the current with respect to the demand.
Common docking point
The PCC, or common point of coupling, is one of the most important concepts of IEEE 519. Compliance is not always evaluated within any internal board. The standard focuses on the point where the interface occurs between the user and the electrical system or between electrical responsibilities.
Correctly defining the CCP is essential to avoid erroneous interpretations.
Problems caused by harmonics
Harmonics can cause:
- Transformer heating.
- Neutral overload.
- Additional losses.
- Resonance with capacitor banks.
- Protection firing.
- Vibration in engines.
- Measurement errors.
- Premature damage to capacitors.
- Interference in control systems.
How to study
A harmonic study normally considers:
- Electrical model of the system.
- harmonic sources.
- Impedances of transformers and cables.
- Capacitor banks.
- Connection point.
- Operation scenarios.
- Existing measurements.
- Applicable limits.
- Filter evaluation.
common mistake
A common misconception is that complying with IEEE 519 means eliminating all harmonics. That's not realistic. The standard seeks to keep the distortion within acceptable limits at the corresponding evaluation point.
Conclusion
IEEE 519 helps organize harmonic analysis and establish compliance criteria. It is especially relevant in modern systems with a high presence of power electronics.
The harmonics review allows us to understand how loads, converters and infrastructure interact, especially when drives, UPS, inverters or BESS systems are incorporated.
If you need to measure harmonics, check distortion or diagnose power quality, check out our service. maintenance and commissioning tests and measurements.