Protections: Overvoltage protection
2023-01-31
Storms can be both beautiful and exciting, as well as dangerous for people and buildings. potential difference (of the order of several thousand volts). Lack of proper protection against these phenomena results in serious damage or destruction electrical and electronic devices.
What are the most common causes of electrical surges?
- direct atmospheric discharges (lightning strikes) into the building's lightning protection system,
- atmospheric discharges into low voltage power grid cables,
- atmospheric overvoltages induced in building installations or other close objects,
- switching overvoltages and emergency states in the power grid.
Ewimar overvoltage protection
Modern devices based on spark gap technology provide both potential equalization in the lightning protection system and two- or three-stage surge protection.
In order to choose the right surge protection system, it is necessary to know many factors that affect the level of risk:
- Location install devices to be protected – inside or outside the building, metal construction
- Extension, structure, length and type of cabling, cable route
- Types of interfaces, types of signals, supply voltage and rated loads
Teletechnical devices, computer networks and its active elements, monitoring are particularly exposed to overvoltages. In addition to the standard, stepped surge protection system, local protection should be used. Their low cost will allow you to protect individual channels, lines and, consequently, avoid material losses and replacement of devices.
Surge protectors of the PTU and PTF series are modern solutions dedicated to the LAN used to protect against the effects of overvoltages and lightning discharges, as well as against attempts to deliberately immobilize the system . These high-class overvoltage protections, dedicated to gigabit LAN networks, based on 5, 5e and 6 category cables.
Surge Protection – 3 stage system.
Types of surge protectors:
- type 1 (class B) – first degree of protection. They allow current to flow to the ground in the form of a 10/350 μs wave, the closest in its characteristics to a surge current wave. That is why protectors of this type have a higher energy discharge efficiency. Used at the point of power supply to the building (main switchgear) and when the electrical installation is exposed to direct impact current, i.e. in cases where:
– the building is equipped with a lightning protection system (lightning rod);
– the building is powered by an overhead line;
– the building is powered from a short cable access (less than 150 m);
– the building has a common earth electrode with other buildings exposed to direct surge current.
- type 2 (class C) – second degree of protection. They allow current to flow to the ground in the form of an 8/20 μs wave, which is closest in its characteristics to current waves due to the indirect effects of a lightning strike. They are used inside the electrical installation behind the main switchgear (perimeter, floor and residential switchboards)
- type 3 (class D) – used for final protection, at the protected device (sockets and boxes).
The last type is often omitted, although it shouldn't be. Already designers and practitioners consider this a mistake, especially since network devices are quite an expensive investment. These and other storm protection devices and teletechnical installations can be found at: