kytkentäylijännitteiden

Kytkentäylijännitteet, often translated as switching overvoltages, refer to transient voltage spikes that occur in electrical power systems during switching operations. These operations include the energization or de-energization of lines, transformers, capacitors, or reactors, as well as fault clearing by circuit breakers. When a circuit is suddenly opened or closed, stored energy in inductive and capacitive elements can be released, leading to rapid fluctuations in voltage.

These overvoltages can be significantly higher than the normal operating voltage of the system. Their magnitude and duration depend on various factors, such as the system's configuration, the inductance and capacitance of the connected equipment, the characteristics of the switching device, and the presence of any nonlinear elements. In some cases, these overvoltages can propagate through the system and affect other connected equipment.

The primary concern with switching overvoltages is their potential to damage or degrade electrical insulation. If the overvoltage magnitude exceeds the insulation strength of equipment, it can lead to flashovers, partial discharges, or complete insulation breakdown, resulting in equipment failure and potentially widespread power outages.

Mitigation strategies for switching overvoltages include using surge arresters, which are devices designed to limit overvoltage by conducting excess current to ground. Other methods involve employing pre-insertion resistors in circuit breakers to reduce the initial rate of rise of voltage, or using controlled switching techniques to synchronize the closing or opening of contacts with specific points in the voltage waveform. Careful system design and analysis are crucial to predicting and controlling these transient phenomena.