RU44888U1 - CABLE FITTINGS - Google Patents

Abstract

The utility model relates to electrical engineering and can be used in protection devices of electrical installations and humans in three-phase (multiphase) networks with isolated neutral. The purpose of the utility model is to increase reliability and facilitate troubleshooting of the device. The cable armature contains a power source 1, two or more junction boxes 2, connected to each other and to a power source 1 through connecting cables 3. Each box 2 has sockets 4. Each junction box 2 is equipped with its own protective shutdown device, and each trip delay time the next box, counted in the direction from the power source, is smaller than the previous one. A sequential protective shutdown of junction boxes 2 is ensured, which in the event of an insulation defect leads to shutdown, first of all, of power tools that are not critical to power outages.

Description

The utility model relates to electrical engineering and can be used in cable accessories to protect electrical installations and humans in three-phase (multiphase) networks with isolated neutral.

Known cable accessories that implements a method of controlling a residual current device, in which the delay time of a trip is changed (Method of controlling a residual current device. RU, patent 2001122598. A, M7. Cl. MKI N 02 H 3/16. Publ. 2003.06.27).

In a known design, when the insulation resistance decreases below an acceptable level, all consumers are disconnected.

Cable reinforcement is also known, containing two or more junction boxes with sockets for supplying and distributing electricity from a mobile power station or a pick-up point, a residual current device that provides insulation control in three-phase current networks with an insulated neutral and has a delay circuit for the operation of the protective disconnection (Decision on the grant of a utility model patent dated October 15, 2004 by application No. 200412504/22 (027478). Device for monitoring insulation resistance and protecting electrical equipment eskoy installation).

The disadvantage of this design is the complexity of troubleshooting.

Closest to the claimed device is a cable armature containing two or more junction boxes with sockets for supplying and distributing electricity from a mobile power station or a pick-up point, a protective shutdown device that provides insulation control in three-phase current networks with an insulated neutral and having a protective response time delay circuit shutdowns (Koptev A.A. Installation of workshop electrical networks

voltage up to 1 kV. Directory of electrician. Ed. A.D.Smirnova et al. - M. Energoatomizdat, 1988.p. 92-93).

In this design, when the insulation resistance decreases below the permissible level, all consumers are disconnected. Identification of a defective tool is carried out by turning off the tools one by one until the protection devices are no longer triggered. The disadvantage of this design is the complexity of troubleshooting. In addition, consumers may find power tools both non-critical and critical to power outages, such as drilling and milling machines, the cutting tool of which may break if it suddenly stops. In the known solution, each group of tools can be connected to a separate cable fitting containing its own protective device, but such a solution does not have the properties of selectively disconnecting various groups of power tools.

The purpose of the utility model is to increase reliability and facilitate troubleshooting of the device.

The solution to the problem is achieved by the fact that the cable fittings containing two or more junction boxes with sockets

for supplying and distributing electric power from a mobile power station or a pick-up point, a protective shutdown device that provides insulation control in three-phase current networks with an isolated neutral and has a protective shutdown delay circuit, each junction box equipped with its own protective shutdown device with a subsequent shutdown delay time for each subsequent boxes, counted in the direction from the source of electricity, smaller than the previous one.

Figure 1 presents a schematic diagram of a device.

Cable accessories include a power source 1 in the form of a mobile power station or a pick-up point, two or more junction boxes 2 connected to each other and to a power source 1 through connecting cables 3. Each box 2 has sockets 4 for distributing and supplying electricity to mechanized traveling power tools with the current maintenance and repair of the track, the construction of railway lines. Each junction box 2 is equipped with its own device.

protective shutdown, and the delay time for disconnecting each subsequent box, counted in the direction from the power source, is less than the previous one.

The device depicted in figure 1, operates as follows.

In normal operation, i.e. if there is insulation resistance between any of the phases and the grounding bus, within the established standards, the current through the protective shutdown device of each junction box 2 does not reach a threshold value, the make contact of its actuator is in the off state, connected to the power source 1, through sockets 4 junction boxes 2, working power tools.

In emergency modes, both asymmetric (i.e., a change in the insulation resistance of each of the phases is different) is possible, as well as symmetrical modes (a change in the resistance of all phases is the same). The leakage current flows through the circuit: phase - leakage resistance (or human body) - making contact of the actuating element of the protective disconnect device of junction box 2, to which the defective

tool. At the same time, the closing contact of the actuator, when it is on, de-energizes all the power tools connected to this junction box 2. To the outlets 4 of junction box 2, which is located closest to the power source 1, power tools critical to power outages are connected. This ensures a sequential protective shutdown of junction boxes 2, which in the event of an insulation defect leads to shutdown, first of all, of power tools that are not critical to power outages. When several protection devices are triggered, the junction boxes 2 are sequentially inspected in the direction from the power source 1. The defect is searched for in the loads of the first disconnected junction box 2 detected in this direction.

Cable fittings are assembled on a modern elemental base. At SKTBR OJSC, cable fittings were tested at a network voltage of 360 V. The fittings have greater sensitivity compared to the prototype, they control a significantly wider range of changes in insulation resistance

and reliably protects both the generator of the network and the person with an asymmetric and symmetric decrease in insulation resistance. The fittings are operable in a wide range of temperatures and electrical noise, possesses the properties of selective shutdown of various groups of power tools.

Claims (1)

Cable fittings, containing two or more junction boxes with sockets for supplying and distributing electricity from a mobile power station or a pick-up point, a residual current circuit breaker that provides insulation monitoring in three-phase current networks with an insulated neutral and has a residual current circuit delay circuit, characterized in that each junction box is equipped with its own residual current circuit breaker with a delay time of each subsequent short circuit the bar, measured in the direction from the electric power source, is smaller than the previous one.