Surge
protection devices (SPD) and surge arresters have the same function: they can
protect electrical equipment from overvoltage conditions, but what is the
difference between them? The following is a brief description of the
differences between them.
1.
Different Rated Voltages:
According
to NEC 2017 Sec 280 & 285, the rated voltage of the surge arrester is over
1KV. They can prevent very large fault currents, such as those caused by
lightning. The rated voltage of SPD does not exceed 1KV, for example. 380V,
220V. Surge arresters 1000 volts or less are also known as Type 1 SPDs.
2.
Different Applications:
Surge
arresters protect medium to high voltage equipment. Utility companies use surge
arresters in power transmission and distribution systems to protect their
electronic equipment and infrastructure. Surge arresters can also be found in
large industrial companies, such as mining, oil, or natural gas. SPD protects
low-voltage equipment for household and civil use, such as washing machines,
refrigerators, or entire houses.
3.
Different installation positions:
The
surge arrester is usually installed on the first system to prevent the direct
intrusion of lightning and protect overhead lines and electrical equipment; the
SPD is usually installed on the auxiliary system, which is a supplement after
the surge arresters eliminate the direct intrusion of lightning or the surge
arresters cannot directly eliminate all the intrusions Measures. Therefore, the
surge arresters are usually installed at the wire entrance, and the SPD is
installed at the terminal socket or signal circuit.
4.
Different Discharge Current Capacity:
Since
the main function of surge arresters is to prevent lightning overvoltage, the
discharge current capacity is relatively high. The discharge current capacity
of SPD is usually not high. The terminal usually uses SPD. It will not be
directly connected to overhead lines. After passing the primary current
limiting function, the lightning current has been limited to a very low value,
so that the SPD with low discharge current capacity can fully protect it. SPD
is suitable for the precise protection of low-voltage power supply systems.
5.
Different materials:
The
main material of surge arresters is Zinc oxide. The main material of SPD varies
according to the grade and classification protection of the torch resistance
(IEC61312). Besides, the design of the SPD is more precise than that of the
surge arresters. Further, from a technical point of view, the response time,
the effect of the pressure limiting aspect, a comprehensive protective effect,
anti-aging performance point of view, the surge arresters do not reach the
level of SPD.
6.
Different sizes:
As
the surge arresters are linked to the main electrical system, they must have
sufficient external insulation performance and a large appearance size. Since
the SPD is connected to the low-voltage system, the size of the SPD can be
small.
We
provides single-phase SPD, three-phase SPD, and DC SPD for solar PV systems
with high quality and the best service.
For more on this, or to learn about any of our other electrical services, contact us today.
