Recently, many customers asked us how to choose a surge protector? How to determine the site of the distribution box to install a surge protector? Some basic functions and parameters to determine how? Today, easy to create a small editor to give you a detailed introduction to the first level of surge protector in the end how to choose.
I. What is a surge protector?
A level of surge protection refers to the 10/350µs waveform impact current T1 class test SPD, so it is also called T1 level surge protector, the power transmission line suffered a direct lightning strike when the huge energy to discharge, effectively protect the building’s internal electrical equipment from the damage of the surge current, therefore, the assessment of the first level of surge protector is mainly the ability to discharge.
GB 50343 -2012 Article 3 of 5.4.3 states that: AC power lines into the building, in the line of the total distribution box, such as LPZ 0A or LPZ 0B and LPZ 1 zone junction, should be set up as the first level of protection of class I test surge protector; that is to say, the first level of surge protector is usually installed in the higher risk of direct lightning in the area, such as the building’s external power lines, the independent locations such as the main distribution box, the main inlet of the main distribution cabinet, and the low-voltage side of the transformer.
II. How to properly purchase a surge protector?
The key parameters of one-level surge protector are inrush current Iimp, maximum continuous voltage Uc, voltage protection level Up and so on.
GB 50057-2012 Article 8 of 4.2.3: In the power supply introduction of the total distribution box should be installed at the level I test surge protector. The voltage protection level of the surge protector shall be ≤2.5kV, and the inrush current of each protection mode shall be ≥12.5kA when it cannot be determined.
NO.1
limp inrush discharge current, refers to the T1 class surge protector throughput, that is, discharge capacity. Class I surge protector, inrush discharge current Iimp commonly used 15kA, 25kA these two specifications;
NO.2
Requirements Up voltage protection level ≤ 2.5kV, because the total distribution box is protected equipment voltage withstand value is generally in the 2.5kV or 4kV, 230/400V distribution system on the market at present, a level of surge protector Iimp value of 12.5kA ~ 50kA, most of which are able to meet the Up ≤ 2.5kV, the lower the value of the level of voltage protection, the better the protection performance. But like high voltage system such as 690VAC, 800VAC, etc., the voltage protection level Up>2.5kV, which is also normal, as long as the effective protection level Up/f on the line is less than the withstand voltage value of the protected equipment;
NO.3
The maximum continuous operating voltage Uc of the surge protector should be selected according to the system voltage, the maximum continuous operating voltage Uc should be greater than the system operating voltage, for 220V/380V three-phase distribution system, Uc is often selected 385V. the national standard inside the preferred value of Uc has:
2、How to choose a safe and reliable surge protector?
NO.1
When there is no surge in the power system, SPD should not have any influence on the working characteristics of the system it is applied to;
NO.2
Fault indication: because the failure of the SPD has almost no effect on the system, so it is difficult to be found, there is a need to have a fault indication function to ensure that the next surge arrives before the replacement of the failure of the SPD, to protect the system from the impact of the lightning current (switching-type one level of surge protector is usually not this function);
NO.3
No working renewal: due to historical reasons, there are three kinds of primary surge protection in our market at present, which are switching type, voltage limiting type and composite type. Among them, the composite type has the advantages of switching type high discharge capacity and voltage-limiting type low residual voltage, there is no switching type has a renewal current and voltage-limiting type has a leakage current short life defects. The emergence of composite type one-level surge protector, on behalf of China’s lightning protection production level has been and the world lightning protector brand stood at the same height, greatly improving the power distribution box on the surge protection ability, while ensuring that the surge protector in the line does not affect the normal power supply, so that the power distribution system stable operation.
In the three-phase power distribution system of the total distribution box at the installation of the surge protector, easy to build recommended YSPD-25HA-385-R/3PN level of surge protector, composite, with energy automatic coordination function, simple installation, no renewal, no leakage current, but also has a fault indication Telecom alarm and other advantages, will be better for the protection of your power distribution system.
