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SOURCES OF POWER DISTURBANCES. Impulsive:. Lightning,switching ,impulses , utility fault clearing. Oscillatory:. Switching of inductive/capacitive load. Interruption. Switching, utility faults, circuit breaker tripping, component failures. Sag. Startup loads, faults. Undervoltage.
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Impulsive: Lightning,switching ,impulses, utility fault clearing Oscillatory: Switching of inductive/capacitive load Interruption Switching, utility faults, circuit breaker tripping, component failures Sag Startup loads, faults Undervoltage Utility faults, load changes
Swell Load changes, utility faults Overvoltage Load changes, utility faults DC offset Faulty rectifiers, power supplies Harmonics Electronic loads (non-linear loads) Interharmonics Control signals, faulty equipment,cycloconverters, frequency converters, induction motors, arcing devices Notching Variable speed drives, arc welders, light dimmers
Noise Transmitters (radio), faulty equipment, ineffective grounding, proximity to EMI/RFI source Voltage fluctuations Transmitters (radio), faulty equipment, ineffective grounding, proximity to EMI/RFI source Power frequency variations Intermittent operation of load equipment