| 摘要 |
Invention herewith described refers to the device for protecting the single-phase consumers from bias caused by an interruption of the zero conductor in low voltage networks which is composed of FID current protective switch (S1) and an assembly of interconnected diodes (D), the zener diode (ZD) and the resistors (R). To one side of the zener diode (ZD) there is connected the diode (D), and to its other side there is connected the resistor (R). With its other side, the diode (D) is connected to the zero conductor (0), the resistor (R) is connected to the protective earthing (ZZ). So connected the diode (D), the zener diode (ZD), and the resistor (R) form a serial connection. At the moment of the zero conductor (0) termination, the zener diode (ZD) conducts the current to the ground and the circuit closes via the protective earthing (Zz) in the structure, through the ground and the operational earthing (ZP) at a nearby substation (TF). Since the sum of the currents is not zero, FID current protective switch (S1) switches off, so the network installation is also off, and consumers are protected because they are not exposed to the phase to phase voltage of 380 V. The FID current protective switch (S1) can not be switched on while the zero conductor (0) is terminated since the current flows to the ground through diode protection device (D), the zener diode (ZD) and the resistors (R1). The protection device is best installed into the switchboard between the zero conductor (0) rail and the rail for the ground, and can be integrated with FID current protective switch (S1) and mounted anywhere on the installation behind this switch. |
