Harmonics Study
In electrical power distribution system, a harmonic is a periodic non-sinusoidal waveform, which can be represented as the summation of a sine wave having an integer multiple of the fundamental frequency (60Hz or 50Hz). If there is a superposition between the fundamental frequency wave and a harmonic frequency wave, a distorted wave is formed. Main sources of harmonic waves are non-linear loads. The use of semi-conductor components causes interference in the form of distortion of current and voltage signals that flow back into the electrical power system. This disturbance is known as a harmonic.
The Harmonic Study is performed by using SKM Power Tools. The power system model and the initial input data is derived from the short circuit, coordination and arc flash study results. Load flow study is performed before running the harmonic study. The motor and panel load in the model are taken from motor and panel schedules. The load flow study provides a close approximation of the bus voltages, the current flowing in each branch circuits.
The harmonic current sources are identified and Case Studies are developed to find the results as required in the study specification. THD voltage and current waveforms are analysed in time domain and frequency response to determine the impact to the bus voltage at specific locations in the power system. The worst-case results are compared to the recommended IEEE limits.
