RU25117U1 - DEVICE FOR PROTECTING LOW VOLTAGE FEEDERS OF ELECTRICAL SUPPLY OF POSTS OF ELECTRIC CENTRALIZATION ON RAILWAYS - Google Patents

Abstract

Device for protecting low-voltage feeders for power supply of electric centralization stations on railways, consisting of a transformer substation to which a power feeder is connected, connected via a circuit breaker to the input panel of the electric centralization station, characterized in that the device is equipped with current sensors in each of the phase wires (A , B, C) and neutral wire (N), differential current protection sensor, control unit for circuit breaker, protection executive unit, an electronic information conversion unit and an emergency mode registration and warning unit, the outputs of the current sensors and the differential current protection sensor are connected to the corresponding inputs of the information conversion electronic unit, the outputs of which are connected respectively through the control unit of the circuit breaker to the executive protection unit, and through the registration and notification unit emergency modes - with an introductory panel installed at the electric centralization station.

Description

DEVICE FOR PROTECTING LOW VOLTAGE FEEDERS

ELECTRICAL POST SUPPLIES

CENTRALIZATION OF RAILWAYS

The device relates to the field of railway automation, telemechanics and communications (ZHATS) and, in particular, to power supply systems of electric centralization (EC) posts, in railway transport, powered by transformer substations (VT) or various power supply points located at railway stations.

Power supply devices for EC posts are known, in which protection under various emergency conditions (for example, during short circuit and overvoltage) is carried out on the side of low-voltage feeders (usually at EC and VT posts) with circuit breakers or fuses for a rated current equal to the rated current of the low-voltage winding transformer in accordance with the design parameters of power supply circuits 1.2. In addition, in order to exclude cases of overheating and damage to linear transformers with a stable short circuit on the low side, time intervals are provided for the operation of circuit breakers 2, 3. This in some cases leads to fires at EC posts and reduces electrical safety requirements, as well as to long delays in the movement of trains.

In addition, the protection methods used under unauthorized conditions on all existing power supply systems for EC posts are not selective and universal for various possible connections: a three-phase 380 V network with isolated neutral, a two-phase 380/220 V network, a single-phase 380 V network and a single-phase 220 V network Known protection devices cannot be used with DC power supply systems. There are also known devices for protecting consumers' power supply circuits, developed according to the requirements of GOST R 50571.1-93 Electrical installations of buildings. However, these protection devices are not multifunctional. For power supply systems of EC posts, it is necessary that the protection devices disconnect the protected object in various accidents both on the load side: with a direct contact of a person with live parts, overloads and short-circuit, leakage currents to the ground through deteriorated insulation, dangerous voltage between the ground and the ground open conductive parts, as well as on the supply side (TP): in case of phase or neutral wire breakage, phase voltage asymmetry (for three-phase version) and phase closure to neutral wire.

In addition, for EC posts, it is necessary to monitor and record emergency conditions, as well as the possibility of prompt notification of electrical consumer services and power supply.

A block diagram of a device for protecting low-voltage feeders for power supply of electric centralization stations is shown in Fig. 1, where it is shown: 1 - transformer substation (power point), 2 - current sensors in each of the phase wires A, B, C and neutral wire N, 3 - differential current protection sensor, 4 - block of the circuit breaker, disconnector, 5 - input panel installed at the EC station, 6 - electronic information conversion unit, 7 - control unit of the circuit breaker, 8 - executive protection unit, 9 - regis block Traction and emergency alerts.

The proposed device for protecting feeders for power supply of EC posts is a low-voltage complete device of external or internal design, installed in the immediate vicinity of transformer substations (TP). Protection is carried out by the magnitude of the currents of both the phase conductors (A, B., C) and the neutral wire of the feeder N by switching on the current sensors 2, as well as by the differential current from the differential current protection sensor 3 (included in the feeder wires according to the project), usually arising from a decrease in insulation in the feeder-load system, or when unauthorized connection of consumer loads (from phase to ground instead of neutral), or in case of violation in the grounding and power supply system of objects that have several feeders from different iders (in Fig. 1, grounding devices are shown at the transformer substation (ZUtp) and at the EC station (ZUets), through which leakage currents 1u can flow). Protection is usually carried out in two stages:

- by means of current sensors 2, an electronic information conversion unit 6 and an independent trip unit 4, high-precision and stable settings of protective shutdowns and high-speed settings of the control unit of the circuit breaker 7 are set by the consumer using the setpoint setpoint of the electronic information conversion unit 6;

- by means of differential and current sensors, as well as four-pole circuit breakers, the limit values of the feeder disconnection settings are provided regardless of the operability of the electronic information conversion unit 6, the logical construction scheme of which combines the above protection levels. At the same time, through the recording and warning unit of emergency modes 9, an alarm is made about the operation of both the power supply system at the EC station and the registration of all emergency and unauthorized modes of power circuits.

The proposed device can be used with all known power supply systems: a three-phase 380 V network with insulated neutral, a two-phase 380/220 V network, a single-phase 380 V network and a single-phase 220 V network, as well as at all voltages with a DC system. At the same time, the required number of versions for the permissible operating current is provided. In addition, the protection in question has the following features: Wach goth cyo - a wide range of switching of protection settings and protection speed (provides selectivity of protection and maximum consideration of the specifics of the power supply object); -the presence of the functions of early detection of feeder currents and early detection of deterioration of the insulation resistance of the feeder (by differential current); - the availability of redundant current and differential current electromagnetic releases to the upper values of the current settings; - availability of non-volatile memory of the reasons of the previous protective shutdowns; -the ability to quickly diagnose and verify by means of a small portable remote control (supplied by request with a batch of devices); -the possibility of subsequent modernization of the power supply of the facility (from two-wire to three-, four- and five-wire) without replacing the device itself. Considering that the need for such devices on the railway network is at least 60 thousand sets, the requirements for minimum cost and low operating costs were taken into account during the development and mass production.

RSHFORMASCHI sources

1. Instructions for the maintenance and repair of power supply devices for signaling and interlocking (CE-4430, 1988).

2. GOST R 50571.1-93 Electrical installations of buildings.

3. Instructions for grounding power supply devices on electrified railways (CE-191, 1993).

The authors:

A.V. Naumov A.A. Naumov .A.V. Nikitin; ; i i --- A.B. Kuzmenko

Claims (1)

Device for protecting low-voltage feeders for power supply of electric centralization stations on railways, consisting of a transformer substation to which a power feeder is connected, connected via a circuit breaker to the input panel of the electric centralization station, characterized in that the device is equipped with current sensors in each of the phase wires (A , B, C) and neutral wire (N), differential current protection sensor, control unit for a circuit breaker, protection executive unit, an electronic information conversion unit and an emergency mode registration and warning unit, the outputs of the current sensors and the differential current protection sensor are connected to the corresponding inputs of the information conversion electronic unit, the outputs of which are connected respectively through the control unit of the circuit breaker to the executive protection unit, and through the registration and notification unit emergency modes - with an introductory panel installed at the electric centralization station.