SU1485352A1 - Device for power supply of low-voltage electrical apparatus - Google Patents

Description

The invention relates to electrical engineering, the Purpose of the invention is to improve the reliability of low-voltage electrical apparatus by reducing the amount of overvoltage. Cases 2 and 4 of devices connected to the line from two sides are each connected to their own earthing switch 3 and 5. Capacitors 7 and 8 are connected to different wires of the line from its two sides. Overvoltage that occurs between different earthing switches when closed to grounding conductor 3 or 5, divided equally by capacitors 7 and 8 of the same capacity. 5 or .. □

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1485352

The invention relates to electrical engineering, in particular, to devices for overvoltage protection of low-voltage electrical devices, metal cases of which are connected to different earthing, with one of the earthing switches used in an electrical or traction network with a high ground fault current, to devices for protection against overvoltage of low-voltage electrical devices for automatic blocking of electrified railways in case of a short circuit of the contact network χ on rails and overvoltage protection devices Nij automatic low-voltage lines and substations and distribution control devices when a short circuit, the ground network 20 with a large current circuit (earthed neutral).

The purpose of the invention is to improve the reliability of low-voltage electrical devices by reducing the amount of overvoltage.

Figure 1 presents the scheme of the proposed device; Fig.2 schematic diagram of the replacement of the proposed device; figure 3-5 - 30

options schemes of the proposed device.

A device for power supply of low-voltage electric devices (figure 1) includes line 1, at one end of which metal cases 2 connected to it electric devices are connected to one earthing switch 3 and at the other end of which metal cases 4 are connected to it electrical devices are connected to another earthing switch 5, a voltage source 6 (and ^) connected in parallel with the wires of line 1, a capacitor 7 connected at one end of the line between one of the passages and a grounding conductor 5, and a capacitor 8 one at the other end of the line between the other of the wires and the ground connection 3.

The basic electrical circuit of the proposed device (FIG. 2) includes a capacitive voltage divider consisting of a series-connected capacitor with a parallel-connected insulation resistance Ζ between the wires and a grounding conductor, a voltage source (C ₂ ) and a capacitor with a parallel

connected insulation resistance Ζ _Μ between the wires and another grounding conductor.

Overvoltage and, arising between earthing 3 and 5 when short-circuited to earthing 3 or 5 of the network with a high current circuit to earth, and voltage and? source divided in half (equally) on the capacitors 7 and 8 of the same capacity. Capacitors 7 and 8 are selected with such a capacity (for example, 0.5-4 μF) so that the condition Ζ ₇ = "Ζ _c and insulation resistance Ζ is satisfied _and practically does not affect the division of overvoltages with the help of capacitors 7 and 8 of the divider.

Reduction of overvoltages at the ends of the line between the wires and ground is achieved by using capacitors 7 and 8 of the same capacity of the overvoltage divider at Ζ _Η ) έΖ ^. The decrease in overvoltage at one end of the line can be reduced up to two times with Ζ _and <. <Ζ ' _and or Ζ “ _Μ .

A device for power supply of low-voltage electric devices (Fig. 3) of an automatic blocking of a single signal point of electrified railways includes line 1, at one end of which a relay cabinet is connected, the metal body 2 of which is connected to the midpoint of a rail choke transformer, and at the other end a cable box, the metal case 4 of which is connected to the earthing switch 5. Parallel to the wires of line 1, a voltage source 6 is connected in the cable box (Ъ = 220 V). The capacitor 8 is connected between one of the wires of line 1 and the case of the relay cabinet, and the capacitor 7 is connected between the other of the wires of line 1 and the case of the cable box.

Overvoltage C ,, arising between different earthing 3 and 5 (the enclosures of the relay cabinet and the box), divided in half (equally) at the ends of the line between the wires and the grounding with capacitors 7 and 8. same capacity "

Figure 4 presents the use of the invention for automatic blocking schemes of a single signal point of electrified railways in the presence of two ways. As grounding use droop.1485352

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sel - transformers corresponding paths.

Figure 5 shows the use of the invention of the automatic blocking of the paired signal point of electrified railways, in which line 1 is connected at one end to the relay end to power the automatic blocking device on one path, and at the other end to the relay cabinet to power the automatic blocking devices another way.

Claims (1)

Claims and A device for power supply of low-voltage electric devices, including a line at the ends of which metal shells connected to the line of devices are connected to different grounds, and a voltage source connected in parallel to the wires of the line, characterized in that, in order to increase the reliability of low-voltage electric devices by reducing the value overvoltage, it is provided with capacitors of the same capacity, with one capacitor connected at one end of the line between one of the wires and the ground iem and the other capacitor is connected at the other end between the other conductor and the other grounded. fig.Z 1485352 1P ιπ