Do You Know About Surge Protection Device - [SPD] ⚔🌩

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Surge Protection Device [SPD]

 

SPD is another protective device that we have in this pile of electrical devices. Actually, it is not one that is meant to protect us when it hits us. An Electric Surge from lightning or something else, which means that if there is a temporary electrical surge, grounding it as best as possible. Now there are SPDs with a few more options. Such as smart SPD which can detect low voltage, control it, send out a signal and connect with the system.

 

REPSUN SPD

There are basically three types of SPDs, type 1, 2, and 3 (there are many more types and classes).

⚠️ Type 1 is, so simply put, one that needs to be loud outside the house.

⚠️ Type 2 means that inside the DB, you need to increase it in the sub DB.

⚠️ Type 3 is like a small fuse at the end and a small SPD. There is a fuse in the multi-plug around the top of the plug. It also belongs to this category.

 A surge often occurs when lightning strikes. The way that lightning comes from the sky to the ground is found in the graphs. There are two ways of lightning strikes: Direct and Indirect. Direct means hitting directly, indirect means like carrom. They come and stick to trees and rocks. Then, two common waveforms have been found for direct and indirect lightning.  

[10/350 microsecond | 8/20 microsecond]

 

Schneider Electric SPD
Schneider Electric SPD

Now that Type 1 SPD is designed to respond well to the 10/350 waveform. It is also said that can discharge the current at its maximum (maximum impulse discharge) at least five times without getting burned. The Type 2 SPD is designed to withstand indirect surges from the 8/20 waveform. But for him, he can do his maximum discharge only once. Impulse Discharge or Maximum Discharge Current is the maximum amperage it can discharge through the earth. Type 1 comes with a value called impulse discharge current. Type 2 is called Imax.

 A Type 1 SPD should be mounted in a box outside the house. Make sure to supply through HRC fuse or MCB. Before this SPD, there is an OCPD (Over current protective device). This SPD should be grounded with a thick earth wire (25mm/35mm). It would be better if there was at least one core in the supply wire. It cannot be too long. It should be grounded at a minimum distance Next Type 2 SPD should be put in every DB inside the house. Although not as much as the previous one, it needs a little thick earth. Put a little bigger than what is usually brought to the DB. It would be better if the SPD is supplied after the main MCB (don't put an isolator on the main) then a protective device will come before the SPD just like the previous one. The line protections (RCD, MCB) that come after that are installed anyway. After that, the type 3 SPD will be louder anyway. Fuse is everywhere. If you have some sensitive or expensive items, you can add an extra SPD. There is also a SPD that can be plugged into the base itself.

Shneider SPD
Shneider SPD

When putting SPD, don't just put it on live. Put 2 Pole or 4 Pole according to the place along with the neutral. Because there is no guarantee that the neutral will not be attacked. It is ok if you put 3 Pole or 3 Single Pole for those that work only with 3 phases. The SPD has a maximum discharge current (Type 2 has Imax, Type 1 has limp) and it is in kiloamperes. 20 is 20,000 amps. If you put it outside, it's okay to get a slightly higher Iimp (not too big, but one higher than the one inside). But if you put it inside, you have to put a lower Imax. Because when the Imax decreases, the sensitivity increases. If a machine is 6 or 10, About 10/20 per house A big one has 20, For buildings, put them above 40.

  • In - Nominal Discharge Current means the current that can grounded normally Imax - Maximum Discharge Current means the maximum amount. If it comes to this amount, you will not be able to get work from SPD again (type 2). 
  • Iimp - maximum impulse discharge current is the same as above. Direct lightning. A Type 1 can approach this maximum amount at least 5 times without getting burned. 
  • Uc - Maximum continuous operating voltage, the maximum number of volts that can be taken continuously. The rated voltage is 230. Even if it goes to 320, it can work continuously. Up - Voltage protection level. This is also in kA (kilo ampere).
You can more information get on via - https://bit.ly/3RL1KeG

Uditha C Amarasena
Electrical Engineer



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