Ylijännitteisiin

Ylijännitteisiin refers to overvoltages, which are electrical potentials that exceed the normal operating level of a system. These events can be transient or sustained and can have damaging effects on electrical equipment. Transient overvoltages are short-lived but can reach very high magnitudes, often caused by lightning strikes or the switching of electrical loads. Sustained overvoltages are longer-lasting and occur when the voltage remains above the rated level for an extended period, typically due to faults in the power system or issues with voltage regulation.

The causes of overvoltages are varied. External sources, such as atmospheric discharges (lightning), are a significant concern, especially in overhead power lines. Internal sources include switching surges, which occur when electrical devices like circuit breakers or capacitors are turned on or off, creating sudden changes in voltage. Resonance phenomena within a power system can also lead to amplified voltages.

The consequences of overvoltages can range from minor performance degradation to catastrophic failure of electrical components. Insulation breakdown is a common result, leading to short circuits and equipment damage. Sensitive electronic devices are particularly vulnerable to even brief overvoltage events. To mitigate these risks, various protection methods are employed. Surge protective devices (SPDs), lightning arresters, and proper grounding techniques are essential for safeguarding electrical systems against the harmful effects of overvoltages.