Harmonics Calculator

Harmonics Calculator (THD)

Fundamental Current/Voltage (I₁ or V₁) Sum of Squares of Harmonics (I₂² + I₃² + ...)

Result will appear here

Harmonics Calculator – Total Harmonic Distortion (THD) Tool

The Harmonics Calculator helps determine Total Harmonic Distortion (THD) in electrical systems. Harmonics are unwanted frequency components that distort the ideal sinusoidal waveform, affecting power quality and system performance.

THD is one of the most important parameters used in power systems, industrial installations, and renewable energy systems to evaluate waveform distortion caused by non-linear loads such as inverters, UPS systems, and variable frequency drives (VFDs).

THD Formula

Total Harmonic Distortion is calculated using:

THD (%) = √(I₂² + I₃² + I₄² + ...) / I₁ × 100

Where:

• I₁ = Fundamental current or voltage
• I₂, I₃, ... = Harmonic components

Higher THD indicates greater waveform distortion and poor power quality.

How to Use This Calculator

Enter the fundamental component value and the sum of squares of harmonic components. Click calculate to instantly get THD percentage.

Example

Fundamental = 100, Harmonic squares sum = 2500

THD = √2500 / 100 × 100 = 50%

Effects of Harmonics

Harmonics cause overheating in electrical equipment, increased losses, insulation stress, and malfunction of sensitive devices. They also reduce system efficiency and can lead to premature failure of transformers and motors.

In industrial systems, excessive harmonics may result in power factor issues, capacitor bank failures, and interference with communication systems.

Sources of Harmonics

Common sources of harmonics include non-linear loads such as computers, LED lighting, rectifiers, inverters, UPS systems, and VFDs. Renewable energy systems, especially solar inverters, also contribute to harmonic distortion.

Harmonic Standards

Standards like IEEE 519 specify acceptable harmonic limits to maintain power quality. Maintaining THD within permissible limits ensures reliable operation of electrical systems.

Reduction of Harmonics

Harmonics can be reduced using filters (passive and active), proper system design, phase balancing, and use of high-quality equipment. Engineers carefully design systems to minimize harmonic distortion.