# IEEE 3002.8-2018 pdf download

IEEE 3002.8-2018 pdf download.Recommended Practice for Conducting Harmonic Studiesand Analysis of Industrial and Commercial Power Systems.

The software can also help in sizing and locating capacitors or passive filters for minimizing the effect of’ harmonics and optimizing system performance.

In cases where a system cannot be easily or accurately modeled in the frequency domain, time-domain simulation programs such as the Electro Magnetics Transients Program (EMTP) are used for harmonic analysis. The output waveforms of’these simulations are then post-processed using the Fast Fourier Transform (FFT) to yield the calculated harmonic spectrum.

System modeling details described here particularly apply to industrial and commercial systems at low and medium voltages, but the basics arc also applicable to other systems and higher voltages. This standard does not deal with active filters as part of the filter design; however, some reference is made to their applications.

It may be said at the outset that harmonic filter design is very closely linked to power factor (PF) requirements of the system (often based on minimizing utility tariffs) and both must be considered at the same time. PF compensation capacitors are also used for a variety of other purposes, such as transformer and conductor sizing, motor starting, and voltage support. PF compensation studies will always take into account the shift in system resonance points and the absorption of harmonics associated with introduction of’ power factor capacitors.

The current revision of’ IEEE Std 519 should be referred to for general information and particularly for harmonic generation from static power converters and other harmonic sources. An exhaustive reference list is provided in Annex A, which should be referred to for details in specific areas.

5. Background

In the context of’ power system harmonic concerns, a nonlinear load or device is one that does not draw a sinusoidal current when excited by a sinusoidal voltage. The most common nonlinear devices are switching devices, such as solid-state converters, which force the conduction of currents for only certain periods and, to a lesser extent, saturatabic impedance devices such as transformers with nonlinear voltage versus impedance characteristics. In computer modeling and simulation, a nonlinear load or device is considered a source of harmonic currents, where harmonic frequencies are generally integer multiples of the system frequency. However, certain nonlinear loads, such as an arc furnace or a cycloconverter, may also have non-integer harmonic frequencies in addition to the expected integer harmonics.

Harmonics, by definition, occur in every cycle of the fundamental component and are calculated as part of the steady-state solution. However, exceptions exist, and harmonics may vary from cycle to cycle. These are termed thne-varing harmonics. Also, harmonics may appear in quasi-steady-state or transient situations, such as in magnetization inrush current of a transf’ormer. This standard does not deal with transient harmonics or time-varying harmonics, which require harmonic source models as a function of time and involve time domain simulations.

The generated harmonic frequencies are dependent upon the type of nonlinear load or device. Most nonlinear loads or devices produce odd harmonics with small even harmonics. However, loads such as arc furnaces produce the entire spectrum of harmonics: odd, even, and non-integer harmonics in between (non-integer harmonics are also referred to as interharinonics). Generally, the amplitude of’the harmonics decreases as the frequency (or the harmonic order) increases.

An ideal current source is one that provides a constant current irrespective of the system impedance seen by the source. In most studies for industrial applications, the nonlinear load or the harmonic source is considered an ideal current source without a Norton’s impedance across the source (i.e., Norton impedance is assumed to be infInite). This approximation is generally reasonable and yields satisfactory results. When the nonlinear device acts like a voltage source, meaning that it has relative fixed voltage wavefbrm distortion rather than fixed current waveform distortion (e.g., a pulse-width-modulated [PWM] inverter, or an arc furnace, or a utility connection), a Thevenin equivalent voltage source model can be used.