Author name: Engr. Aneel Kumar

Rotating machines also act as source of harmonics in power system. Causes of harmonics generation in rotating electrical machines are classified into following categories: 1. MAGNETIC NONLINEARITIES OF THE CORE MATERIAL: Nonlinear magnetization characteristics of the core material cause harmonic generation. 2. NON UNIFORM FLUX DISTRIBUTION IN AIR GAP: often it is assumed that the […]

Following is the summary of how harmonics affect on power system components. GENERATOR: Production of pulsating or oscillating torques which involve torsional oscillations of rotor elements of TG set and rotor heating MOTOR: Stator and rotor copper losses increase due to harmonic current flow, leakage flux created by harmonic currents causes additional stator and rotor

EFFECTS OF HARMONICS ON GENERATORS In comparison with utility power supplies, the effects of harmonic voltages and harmonic currents are significantly more pronounced on generators (esp. stand-alone generators used a back-up or those on the ships or used in marine applications) due to their source impedance being typically three to four times that of utility

a) Power factor correction capacitors are generally installed in industrial plants and commercial buildings. Fluorescent lighting used in these facilities also normally has capacitors fitted internally to improve the individual light fittings own power factor. The harmonic currents can interact with these capacitances and system inductances, and occasionally excite parallel resonance which can over heat,

There are different causes for power system transients. For example, lightning strokes to the wires in the power system or to ground and component switching either of network components or end user equipment can produce transients. Nature of power system transients are very much event dependent. Short duration events can be classified into three classes:

In electrical power system, harmonics are not desirable in most of the applications and operations. Harmonics have adverse effect on power system equipment as well as on its operation. Harmonics can create resonance in power system network. Damping property may change due to the presence of harmonics. Also it has some adverse effects on performance

IEEE Task Force on the Effects of Harmonics on Equipment has made a wide study on this matter. The result can be summarized as follows: 1. TELEVISION RECEIVERS: Harmonics changes in TV picture size and brightness. Inter-harmonics changes amplitude modulation of the fundamental frequency. For example, even a 0.5% inter-harmonic level can produce periodic enlargement

Harmonics has effect on Capacitor Banks in various ways 1. DIELECTRIC LOSS: Harmonic voltage increases the dielectric loss in capacitors. 2. THERMAL STRESS: Harmonic voltage increases the stress on capacitor bank and the system connected to the bank. 3. RESONANCE: Harmonics cause series and parallel resonances between the capacitors and the rest of the system.

1. Harmonics degrade the operating characteristics of protective relays. Effect of harmonics on relay depends on the design features and principles of operation. 2. Some digital relays and algorithms operate on sample data and zero crossing moment. Harmonic distortion creates error on such operation. 3. Harmonics make higher di/dt at zero crossings and the current