Ylijännitteitä

Ylijännitteitä, often translated as overvoltages, are temporary increases in voltage above the nominal or intended level within an electrical system. These events can be caused by a variety of factors, both internal and external to the power grid.

One common cause of ylijännitteitä is lightning strikes. When lightning hits a power line or nearby structure, it can induce significant voltage surges that propagate through the system. Switching operations, such as the opening or closing of circuit breakers or the energization of large loads, can also generate transient overvoltages. These are often referred to as switching surges.

Internal to a system, faults or short circuits can also lead to temporary overvoltages as protective devices operate to isolate the fault. Other less common causes include the sudden loss of a large load, which can cause generators to overspeed and temporarily increase voltage.

Ylijännitteitä can pose a significant threat to electrical equipment. Sensitive electronic components, insulators, and even larger machinery can be damaged or destroyed by the excessive voltage, leading to costly repairs and service interruptions.

To mitigate the risks associated with ylijännitteitä, various protective measures are employed. Surge arresters, also known as surge protective devices, are installed at critical points in the electrical system to divert excessive voltage to the ground. Proper grounding techniques are also essential for dissipating surge energy safely. Furthermore, careful system design and maintenance practices help to minimize the likelihood and impact of overvoltage events.