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).
Voltage protection is an important electrical protection method that aims to ensure that equipment in the power system can operate safely when the voltage is abnormal. When the voltage in the power system is too high or too low, exceeding the range that the equipment can withstand, the voltage protection will trigger the protection mechanism and […]
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 […]
When it comes to electrical safety, there’s nothing more important than having the proper circuit protection in place. Whether you’re dealing with a commercial or residential application, DC Mini Circuit Breakers (DC MCBs) can provide important benefits and peace of mind. DC Mini Circuit Breakers (DC MCBs) are widely used in solar system. DC power is commonly […]
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