Elements of the protection system

Elements of the protection system

A SPD must always be installed at the origin of the electrical installation.

Location and type of SPD

The type of SPD to be installed at the origin of the installation depends on whether or not a lightning protection system is present. If the building is fitted with a lightning protection system (as per IEC 62305), a Type 1 SPD should be installed.

For SPD installed at the incoming end of the installation, the IEC 60364 installation standards lay down minimum values for the following 2 characteristics:

1. Nominal discharge current In = 5 kA (8/20) µs;

2. Voltage protection level Up (at In) < 2.5 kV.

The number of additional SPDs to be installed is determined by:

3. the size of the site and the difficulty of installing bonding conductors. On large sites, it is essential to install a SPD at the incoming end of each subdistribution enclosure.

4. the distance separating sensitive loads to be protected from the incoming end protection device. When the loads are located more than 10 meters away from the incoming-end protection device, it is necessary to provide for additional fine protection as close as possible to sensitive loads. The phenomena of wave reflection is increasing from 10 meters see Propagation of a lightning wave

5. the risk of exposure. In the case of a very exposed site, the incoming-end SPD cannot ensure both a high flow of lightning current and a sufficiently low voltage protection level. In particular, a Type 1 SPD is generally accompanied by a Type 2 SPD.

The table in Figure1 below shows the quantity and type of SPD to be set up on the basis of the two factors defined above.

Fig.1 – The 4 cases of SPD implementation

Protection distributed levels

Several protection levels of SPD allows the energy to be distributed among several SPDs, as shown in Figure 2 in which the three types of SPD are provided for:

1. Type 1: when the building is fitted with a lightning protection system and located at the incoming end of the installation, it absorbs a very large quantity of energy;

2. Type 2: absorbs residual overvoltages;

3. Type 3: provides “fine” protection if necessary for the most sensitive equipment located very close to the loads.

Related Posts

DC Isolator Switch

DC Isolator Switch

Application   L1 Series DC Isolator Switch is applied to 1-20KW residential or commercial photovoltaic system, pleced between photovoltage modules and inverters. Arcing time is less than 8ms, that keeps solar system more safe. To ensure its stability and long service life, our products are made by components with optimum quality. Max voltage is up […]

Technical Characteristics of SPDs

Technical Characteristics of SPDs

SPDs’ operating characteristics are defined by several technical characteristics. The following are some technical characteristics that should be considered: maximum continuous operating voltage, ac or dc application, nominal discharge current (defined by a magnitude and waveform), voltage-protection level (the terminal voltage that is present when the SPDs are discharging a specific current) and temporary overvoltage […]

​The development prospects of solar connectors

​The development prospects of solar connectors

As the world continues to shift towards cleaner and more sustainable energy sources, the development of solar connectors has become increasingly important. These small, yet essential components of solar panel systems are responsible for connecting the panels together and ensuring them operating at maximum efficiency. In this article, we will explore the current state of […]