Overvoltage is an electrical fault that can endanger equipment connected to a particular power system. It is defined as any instance of a voltage level exceeding the rated voltage of a circuit or circuit element.
Overvoltages can be distinguished by their cause, category of strength, and their duration. Different overvoltage durations have distinct wavelength forms and frequency ranges. This article explores temporary, slow-front, and fast-front overvoltages to outline their causes and effects on power systems.
Temporary Overvoltage
Temporary overvoltages (TOV) have a low magnitude of power above a circuit’s operating voltage but last for a relatively long time. They are undamped or weakly damped oscillatory waves measured either from phase-to-phase or phase-to-ground that can last a few seconds to several minutes. They typically originate from faults, suddenly switching loads, resonance/harmonics, or a combination of these irregularities. Temporary overvoltages stress insulation and equipment, leading to breakdowns and potential failures.
Slow-Front Overvoltage
Slow-front overvoltage (SFO), also known as switching overvoltage, is a type of transient overvoltage that takes between 20 and 5,000 microseconds to reach its peak. It is characterized by its high amplitude, unidirectional or high oscillation, and highly damped wavelength. Once it gradually rises to its peak voltage, the tail duration lasts fewer than 20 milliseconds. It is most often caused by switching power system operations routinely carried out in their testing process, but it also occurs due to lightning strikes and fault clearing.
Fast-Front Overvoltage
Fast-front overvoltage is another transient overvoltage with an even shorter duration than slow-front overvoltage. It is often caused by switching operations at a disconnector switch or faults in gas-insulated switchgear (GIS). It is unidirectional and has a total duration of fewer than three microseconds. Fast-front overvoltages can cause immediate and severe damage to electrical equipment, including insulators and transformers.
Understanding and mitigating these types of overvoltage is essential for maintaining power system reliability and safety. Frequency converters play a crucial role in preventing overvoltage by ensuring that electrical systems operate within their designated voltage specifications. Consider integrating a frequency converter 60hz to 50hz from Visicomm Industries to enhance the overall performance of your electrical infrastructure.