Ylijännitetasain

Ylijännitetasain, known in English as an overvoltage limiter or surge arrester, is a device designed to protect electrical equipment from damage caused by voltage spikes or surges. These surges can be caused by various sources, including lightning strikes, switching operations within the power grid, or faults in the electrical system. The primary function of an ylijännitetasain is to conduct excessive voltage away from sensitive equipment and safely to the ground.

The operation of an ylijännitetasain typically involves a non-linear resistance element. Under normal operating voltages, the resistance of this element is very high, effectively isolating the protected equipment from the grounding path. However, when the voltage exceeds a predetermined threshold, the resistance of the element rapidly decreases. This low resistance path allows the surge current to flow to the ground, bypassing the equipment and preventing it from experiencing the damaging overvoltage. Once the surge has passed and the voltage returns to normal, the resistance of the ylijännitetasain returns to its high state, re-establishing normal operation.

Ylijännitetasaimet are crucial components in electrical distribution and transmission systems, as well as in the protection of electronic devices. They are installed at various points, such as substations, along power lines, and directly on or near the equipment they are intended to safeguard. Their use significantly enhances the reliability and longevity of electrical infrastructure and electronic devices by mitigating the destructive effects of transient overvoltages.