Harmonic Analysis a Root Cause Finder for Repetitive Failure

How NLL affect today's electrical power system? A study of electrical power harmonic analysis helps to know the root cause of equipment and drive failure for correctional power-related steps. Today's Engineers are finding a power quality problem that is becoming increasingly apparent is the harmonic distortions of the fundamental waveform. The problem has arisen due to extensive use of Non-Linear Loads (NLL) in today's electrical power system, which alter sinusoidal shape of the sine wave, and thereby cause harmonic generations and distortion power factor (PF) in the power System.

Measurement units of Power Quality Harmonics are defined by Total Voltage Harmonic Distortion THDv and Total Current Harmonic Distortion THDi. THD values are calculated as the sum of square root of individual harmonics namely 2nd, 3rd, 4th, 5th, 6th, 7th, ... nth divided by fundamental current/voltage. The fundamental harmonics are the 50hz/ 60hz values for voltage and current.

Harmonics are as old a phenomenon as the introduction of the AC System. Mercury Arc Rectifier (MAR) developed in 1920's and Semiconductor Controlled Rectifiers (SCR) and Thyristors developed in 1950's created harmonics due to their nature of non-linear-load. Its usage was much lesser then, typically 5% in 1960, that could not have created any significant impact on the power system. However, economic prosperity coupled with technological advancements have mandated today's comfort conditions those necessitate employing matching controls which are increasingly introducing nonlinear loads which are altering the very sinusoidal characteristic of current and voltage waveforms and creating Harmonics and bad Power Quality.