ommon mode SPD between phase and PE or phase and PEN is installed whatever type of system earthing arrangement (see Fig. 1).
The neutral earthing resistor R1 used for the pylons has a lower resistance than the earthing resistor R2 used for the installation.
The lightning current will flow through circuit ABCD to earth via the easiest path. It will pass through varistors V1 and V2 in series, causing a differential voltage equal to twice the Up voltage of the SPD (Up1 + Up2) to appear at the terminals of A and C at the entrance to the installation in extreme cases.
To protect the loads between Ph and N effectively, the differential mode voltage (between A and C) must be reduced.
Another SPD architecture is therefore used (see Fig.2)
The lightning current flows through circuit ABH which has a lower impedance than circuit ABCD, as the impedance of the component used between B and H is null (gas filled spark gap). In this case, the differential voltage is equal to the residual voltage of the SPD (Up2).
Dc fuse is a very easy to use protection facilities, when the abnormal circuit is often accompanied by rising current, the rising current will not only damage some key equipment, but also burn the circuit, cause a fire and directly cause great economic losses. After the DC fuse is installed, when the current exceeds the current value that […]
In general, DC surge protection can provide significant benefits and advantages, especially in scenarios where the equipment is sensitive to voltage fluctuations or where there is a high risk of power surges. Benefits of DC Surge Protection Protection of Sensitive Equipment: Many electronic devices, especially those using DC power supplies, are sensitive to voltage fluctuations. Power surges […]
Operating voltage Uc Depending on the system earthing arrangement, the maximum continuous operating voltage Uc of SPD must be equal to or greater than the values shown in the table in Figure 1. Fig.1 – Stipulated minimum value of Uc for SPDs depending on the system earthing arrangement (based on Table 534.2 of the IEC […]
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