Power Quality & Harmonics Analysis
THD assessment, harmonic filter design, resonance analysis, and power quality issue mitigation for inverter-based and nonlinear load systems.
What is Power Quality & Harmonics Analysis?
Power quality and harmonics analysis evaluates voltage and current waveform distortion caused by inverters, drives, and other nonlinear loads. The study quantifies Total Harmonic Distortion (THD), assesses compliance with IEEE 519 and utility interconnection limits, and identifies resonance risks that can amplify harmonic content.
Results inform filter design, equipment selection, control tuning, and interconnection strategy. The analysis identifies whether harmonics may cause equipment overheating, nuisance tripping, metering errors, or interference with controls and communication systems.
This study is critical for solar PV, BESS, wind, data centers, industrial facilities, and any system with significant inverter penetration or nonlinear load content. It supports utility interconnection approval and ensures long-term system reliability.
When This Study Is Required
Inverter-Based Generation
Solar PV, BESS, wind requiring harmonic compliance verification
Industrial Facilities
VFDs, rectifiers, arc furnaces, data centers
Power Quality Problems
Equipment failures, unexplained trips, heating issues
Utility Requirements
Interconnection application harmonic assessment
What eGridSync Delivers
Harmonic spectrum analysis (voltage and current THD by frequency)
IEEE 519 compliance assessment (TDD limits at PCC)
Resonance analysis and frequency scan
Filter design recommendations (passive, active, or hybrid)
Inverter control optimization suggestions
Flicker assessment (if applicable per IEEE 1453)
Equipment impact evaluation (capacitor banks, transformers)
Mitigation strategy options and trade-offs
Final report with harmonic plots and recommendations
Inputs Required (Data Request Checklist)
| Item | Examples | Why Required |
|---|---|---|
| System one-line & topology | Inverters, transformers, capacitors, filters | Define harmonic sources and paths |
| Inverter/drive data | Type, ratings, switching frequency, controls | Harmonic emission characteristics |
| Load profile | MW/MVA, operating modes, nonlinear content | Determines harmonic levels |
| Utility source impedance | Short-circuit level, X/R ratio | Affects voltage distortion and resonance |
| Existing measurements (optional) | Power quality meter data | Validation and calibration |
| Compliance limits | Utility or IEEE 519 requirements | Pass/fail criteria |
Key Power Quality Concepts
THD vs TDD
THD measures total distortion; TDD normalizes to demand load
Resonance
Capacitance and inductance creating amplification at specific frequencies
Harmonic Filters
Passive or active devices to reduce harmonic content
IEEE 519 Limits
Industry standard for acceptable harmonic distortion levels
Common Power Quality Issues
Harmonic Resonance
Capacitor banks amplifying harmonics causing equipment damage or failures
Exceeded IEEE 519 Limits
TDD violations requiring mitigation before utility interconnection approval
Equipment Overheating
Transformers, cables, or capacitors experiencing excess losses from harmonics
Control or Metering Interference
Harmonics affecting relay performance, meters, or communication systems
Frequently Asked Questions
What is harmonic distortion?
Non-sinusoidal waveforms from inverters and nonlinear loads creating voltage/current distortion.
What are THD and TDD?
THD is Total Harmonic Distortion; TDD is Total Demand Distortion normalized to load level.
Do inverters cause harmonics?
Yes—modern inverters are designed to limit harmonics but interactions can occur.
Can you design filters?
Yes—passive or active filter recommendations based on requirements.
What causes resonance?
Capacitors and system inductance creating resonant frequencies that amplify harmonics.
Do you assess voltage quality?
Yes—flicker, sags, swells, and transient behavior as needed.
What standards apply?
IEEE 519 for harmonics; IEEE 1453 for flicker; utility interconnection requirements.
Can measurements validate models?
Yes—field data improves accuracy if available.
What if limits are exceeded?
We recommend mitigation: filters, control changes, or system modifications.
How long does this study take?
Typically 3-5 weeks depending on complexity and data availability.
Ready for Power Quality Analysis?
Contact eGridSync for harmonics assessment and IEEE 519 compliance support.