Industry News

How to interpret the electrical parameters of surge arresters?

2022-06-29

1. Uc:277v, which refers to the maximum rated voltage applicable to lightning arrester products during long-term operation;

The household voltage in Europe and China is 220V, but this is not constant. There is a fluctuation error, but the maximum voltage is generally 277v. Within this maximum voltage, the lightning arrester can be used normally for a long time without damage.


2. Up value, which refers to the protection voltage of lightning arrester products after lightning strike, that is, the residual voltage after lightning strike; American gauge calls the residual pressure value MLV value;

In case of lightning strike, the maximum voltage generated after the lightning passes through the lightning arrester shall not exceed 1500V, that is, the voltage on the light source shall not exceed 1500V after lightning strike; However, there is also an error of 20% up and down, that is, the lowest voltage after lightning current passes through this lightning arrester may be only 1200V, while the highest voltage through this lightning arrester may reach 1800V;

Note: the smaller the up value, the better! The smaller the up value is, the smaller the residual voltage generated during lightning stroke is, so the impact on the product is smaller, but it also means that the higher the technical level of the lightning arrester manufacturer is required!

If the customer does not put forward specific requirements for up value, the residual voltage value of our company for European and American Certification is ≤ 1500V, but in fact, we can customize lightning arresters with different up values according to the customer's specific requirements.


3. In (8/20us): This refers to the current intensity of standard discharge of lightning arrester within 8-20 microseconds;

That is, within this time, the product can withstand the current impact strength without damage; Why 8 microseconds - 20 microseconds? This is because the lightning strike process in nature usually takes such a long time;

According to the available data, Malaysia requires an in value of 3.5ka, China, Europe and the Americas require an in value of 5ka, while Japan requires an in value of 6ka.


4. IMAX (8/20us):10ka, which refers to the maximum power on flow intensity of lightning arrester

That is, the product can withstand 10kA current without damage within 8-20 microseconds; IMAX value required around the world is generally 10kA; Special places, such as strong lightning strike areas, also require 20KA.


5. UOC 10kV, which refers to the open circuit voltage of the product

That is, the lightning strike voltage that the protected appliance can withstand when it is closed and not in use.

In our common cognition, we think that although the plug of the electrical appliance is inserted into the socket, as long as the electrical appliance is not used, even if it thunders, it will not be damaged by lightning, but in fact, this concept is wrong! As long as the lightning strike is strong enough, even if the electrical appliance is turned off and not in use, it may still be damaged by the lightning!

When the street lamp light source is not turned off and is still in the power on state, the maximum withstand voltage of the street lamp light source can still reach 10kV due to the protection of lightning arrester, which effectively improves the high voltage impact resistance of the whole street lamp.


6. Mcov 320v refers to the maximum voltage that the lightning arrester can maintain normal operation in a short time:

That is, during power on, the lightning arrester can maintain normal operation in a short time under the maximum voltage of 320v;

(1) when the mains cable connected to the street lamp is 220V, the mcov value of the lightning arrester product is 320v;

⑵ when the mains cable connected to the street lamp is 380V, the mcov value of the lightning arrester product is 420v;


7. T2, T3: This indicates the protection grade of lightning arrester products;

(1) T2 means that the lightning arrester is a secondary lightning arrester; Each electrical parameter of the secondary lightning arrester is relatively large, so its volume is also relatively large. It is generally applicable to the incoming circuit of electrical products, such as the distribution box installed under the street lamp pole, and under normal circumstances, the parallel circuit design is adopted;

(2) T3 means that the lightning arrester is a class III lightning arrester; The volume of the three-level lightning arrester is relatively small, so it is suitable to be installed in the narrow space inside the electrical products. Under normal circumstances, the series circuit design is adopted.




8. American gauge has a very special type 5ca lightning arrester, which is not equipped with tripping protection device, and the shell is made of heat shrinkable sleeve, so the unit price is very low. But there will be a hidden danger: when lightning strikes the lightning arrester, the lightning arrester will catch fire! However, many company technicians do not know this, or deliberately ignore it, because many of them believe that:

Since the product has been certified according to American regulations, there should be no problem. Therefore, in order to reduce the cost, we often choose to use this low-level and low-cost product. When used alone, if the lightning strike intensity exceeds the withstand value of the lightning arrester, there is more than 90% probability of fire!

This low-level product is not accepted by European regulations and Chinese standards, and will not be certified. Therefore, we strongly recommend that customers choose to use lightning arresters with tripping protection parts!