Surge Protector Selection - Spd Current Value Selection

Publish Time: 02/27 2025 Author: Site Editor Visit: 120

Surge protectors are generally connected in parallel to the main circuit. They usually have high impedance properties. When TOV appears in the circuit, they will conduct and discharge surge current. The selection basis of the current value (flow rate) of the SPD surge protection device is the lightning protection level of the building and the lightning protection zone (the location of the distribution box in the building). Yizao Xiaobian will introduce the relevant provisions of the national standard:

1. Lightning protection level of buildings

National standard GB 50343-2012 Section 4.3.1: The electronic information system of the building can be selected according to Table 4.3.1 to determine the lightning protection level of the building based on its importance, economy and value.

Electronic information systems for buildings

Grade A

1. Electronic information systems for national computing centers, national communication hubs, special and first-class financial facilities, large and medium-sized airports, national and provincial radio and television centers, hub ports, railway hubs, and important urban public facilities such as water, electricity, gas, and heat in provincial cities;

2. First-class security units, such as closed-circuit television monitoring and alarm systems for national cultural relics and archives;

3. Electronic medical equipment for tertiary hospitals

Grade B

1. Electronic information systems for medium-sized computing centers, second-class financial facilities, medium-sized communication hubs, mobile communication base stations, large stadiums (halls), small airports, large ports, and large railway stations;

2. Second-class security units, such as closed-circuit television monitoring and alarm systems for provincial cultural relics and archives;

3. Electronic information systems for radar stations and microwave stations, and highway monitoring and toll collection systems;

4. Electronic medical equipment for second-class hospitals;

5. Electronic information systems for five-star and higher-star hotels

Grade C

1. 1. Electronic information systems of third-level financial facilities and small communication hubs;

2. Large and medium-sized cable TV systems;

3. Electronic information systems of hotels of four stars and below

Class D

General-purpose electronic information equipment that needs protection, except for the above-mentioned Class A, B, and C

2. Lightning protection zoning

Lightning protection zoning is the theoretical basis of lightning protection. Various forms of lightning protection measures are based on the theory of lightning protection zoning, and are also the theoretical basis for the selection of surge protectors.

National Standard GB50343-2012 Section 3.2: Buildings that need to protect and control the lightning electromagnetic pulse environment should be divided into different lightning protection zones according to the provisions of this specification.

GB50343 Table 4.3.1 Lightning protection zoning division

LPZ0A zone

Areas threatened by direct lightning strikes and all lightning electromagnetic fields. The internal systems in this area may be affected by

all or part of the lightning surge current;

LPZ0B zone

A protection area for direct lightning strikes, the threat in this area is still all lightning electromagnetic fields.

The internal system of this area may be affected by some lightning surge currents;

LPZ1 area

The area where surge current is limited due to the shunt at the boundary and the action of surge protective device.

The spatial shielding of this area can attenuate lightning electromagnetic fields;

LPZ2 ~ n subsequent lightning protection zone

The area where surge current is further limited due to the shunt at the boundary and the action of surge protectors.

The spatial shielding of this area can further attenuate lightning electromagnetic fields.

Building lightning protection zone plan

Surge protector selection-building lightning protection zone plan

National standard 50343 5.4.3-3:

Recommended values of impulse current and nominal discharge current parameters of power line surge protector

The above figure is the recommended value of the surge protector flow rate specified by the national standard according to the building protection level and lightning protection zone. Users can select the impulse current and nominal discharge current of the surge protector according to the actual situation of the project.

To facilitate your direct selection, the following are the product models of Yizao surge protectors. I hope it will be helpful for your SPD surge protector selection. If you need more information, please call: 133-8651-1449

Surge Protector Selection - Spd Current Value Selection