RU2647108C1 - Method of partly non-selective protection of a threshold ac network - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention relates to power supply for electric networks contacting with current collectors of vehicles. Method of partially non-selective protection of an AC traction network is that the absence of a short circuit in the accidentally disconnected contact network is verified by means of a short-circuit monitoring device for induced voltage, and in the absence of a short circuit, a command is given to turn on the emergency-off supply line with a minimum time delay by automatic restart. Traction AC network contains a post-section with circuit breakers, voltage and current transformers for each supply line of the contact network and intelligent terminals with a protection device and automatic re-activation of the emergency power supply line of the contact network of the partitioning station. And the basic protections are carried out with zero time delay.

EFFECT: technical result of the invention consists in a significant reduction of the voltage recovery time in the contact network in emergency situations.

1 cl, 1 dwg

Description

FIELD OF THE INVENTION

First of all, the invention relates to a method for partially non-selective protection of a traction AC network. In general, the invention relates to an electric power supply system for traction AC networks, namely, to automation of sections for sectioning a contact AC network.

State of the art

In [1], a variant of partially non-selective protection of the supply lines of the contact network of AC section posts was proposed, when the main protections were made with zero time delay in order to significantly reduce the number of contact network burnouts. It is assumed that the sections of the contact network on the circuit breakers are made by NIIEFA-ENERGO [2], that is, each contact network feeder is equipped with voltage and current transformers connected to the circuit breakers, and the protection and automation (automatic reconnection) are carried out on InTer smart terminals. In [3, 4], it was proposed to introduce a device for determining the presence (absence) of a short circuit (KZ) in an emergency-disconnected contact network for monitoring induced voltage in the traction network in order to realize automatic re-activation (AR) of the contact line supply circuit breaker.

Thus, in accordance with the prototype [1], a method of partially non-selective protection of an alternating current traction network with a sectioning station (PS) with switches, voltage and current transformers for each supply line of the contact network and Inter smart terminals with a protection and emergency automation device is considered, moreover Basic protections are performed with zero time delay.

The disadvantages of the prototype are determined by existing regulatory documents [5 and 6]. According to the standard [6], the automatic reclosure of circuit breakers of a sectioning station is made dependent on the incoming voltage from a traction substation, and since the automatic reclosure of supply lines of a contact network of a traction substation is performed with a time delay of at least 5 seconds, the automatic reclosure of supply lines of a section post will be more than 5 sec. This means that during emergency shutdowns of switches in the traction network and their subsequent automatic reclosure, the voltage in the contact network will be absent for more than 5 seconds. For this reason, for example, when working in the traction network of VL-80 electric locomotives with (with a machine phase splitter), whose circuits are “disassembled” after 1.5-2 sec., The restoration of the traction mode can occur after a time of at least 1-2 minutes [ four]. This situation is currently observed in most parts of the network of domestic railways, which use electric rolling stock with engine phase splitters [4]. With a heavy train on a rise of more than 6%, under the indicated circumstances, the train may stop with negative consequences. The same picture occurs with selective methods of protecting traction AC networks.

Thus, for reliable power supply, it is necessary after an emergency shutdown of the circuit breaker to determine whether the short circuit has disappeared, and for short-circuit short circuits (that is, disappearing after disconnecting the voltage on the contact network), an automatic reclosure with a reduced reclosure time of at least 1-1 2 sec

Disclosure of invention

The objective of the invention is to minimize the absence of voltage in the contact network during emergency outages and undergoing short circuit.

The technical result of the present invention is to significantly reduce the time of voltage recovery in the contact network in emergency situations, and, in particular, in the exclusion of cases of stopping heavy trains when passing short-circuit. In addition, in contrast to the installation of a short circuit search device (UPC) at a traction substation, the installation of a UPC at a sectioning station does not require the installation of voltage transformers, since they are installed according to the design on all supply lines of the sectioning station, and this reduces the capital cost of implementing the invention.

To implement the above technical result, a method is proposed for partially non-selective protection of an alternating current traction network, comprising a sectioning station with switches, voltage and current transformers for each supply line of the contact network and smart terminals with a protection device and automatic restart of the emergency disconnected supply line of the contact network of the sectioning station, moreover, the main protections are carried out with a zero time delay, while checking the absence of a short circuit Puts in the emergency-disconnected contact network by means of the short-circuit monitoring device for the induced voltage and in the absence of a short-circuit, a command is issued to turn on the emergency-disconnected supply line with a minimum delay time by automatically reconnecting.

In [3], it was proposed to set the AR delay time to set 3 seconds to tune out the operation of the circuit breaker failure backup device (CBD). However, such a solution was developed for the general case of power supply to the traction network. In particular, if sectioning posts are installed on the disconnectors, the automatic reclosure time delay of 3 seconds is necessary to reliably determine the absence (presence) of short circuit after disconnecting all circuit breakers supplying the short circuit, even if the backup circuit breaker backup device (CBD) is operating. If the posts are on switches with individual protections, then the automatic reclosure time can be significantly reduced, since in this case it is necessary to control the disconnected state of only one traction substation switch that supplies the contact network section with a short circuit. For this option, we determine the setting of the reclosure of the supply line of the contact network of the sectioning station. We believe that the short circuit is switched off by the second stage of the distance protection of the supply line of the contact network of the traction substation, the time delay of which is 0.5 seconds (the maximum possible by standard [5]). Even taking into account the implementation of the redundancy function of the circuit breaker (CBD), it will turn off after a time of no more than 0.5 seconds [6]. Thus, taking into account the stock time (0.3 sec), the automatic reclosure setting of the supply line of the contact network of the sectioning post will be 0.5 + 0.3 = 0.8 sec. If we take the time delay of the second stage of distance protection of the traction substation 0.3-0.4 sec, as it is practically done, then the automatic reclosure time of the supply line of the contact network of the sectioning post can be reduced to 0.6-0.7 sec.

So, it is shown that the automatic reclosure of the supply line of the contact network of the sectioning station on circuit breakers with individual protection when controlling the presence (absence) of faults can be set within (0.3-0.4) + 0.3 = 0.6-0.7 sec., which will ensure minimal voltage absence in the contact network and stable operation of the electric rolling stock. The specified position is fundamental and will be used later in the invention for sections of the contact network, when the short circuit is switched off by switches and traction substation and section section. Indeed, when the reclosure time is reduced to 0.6-0.7 sec during passing short circuits, the locomotive circuitry will not be “disassembled” and, therefore, its traction mode will not be violated, which distinguishes the proposal according to the invention from the existing situation with “EPS circuit analysis” when AR delay by 3 sec. Thus, reducing the reclosure time to the minimum possible 0.6-0.7 sec solves the problem of preserving the EPS circuit during passing faults.

Brief Description of the Drawings

To explain the proposed method of partially non-selective protection of the traction AC network, the drawing shows a section post scheme.

"Implementation of the invention"

In the drawing, the following notation:

1 - Bus post sectioning; 2, 3, 4, 5 - switches; 6, 7 - contact network; 8 - current transformer; 9 - voltage transformer; 10 - intelligent terminal Inter connections; 11 - protection and automation unit BZA in Inter; 12 - block control device short circuit UKKZ; 13 - block device search short circuit UPKZ; 14 - automation unit of the feeder contact network to the switch 5; 15, 16, 17 - the same for switches 2, 3, 4; 18 - point short circuit (short circuit).

The sectioning station is equipped according to the scheme of NIIEFA-ENERGO [2] with four switches 2, 3, 4, 5. The transformers 8 and voltage 9 of the switch 5 are connected to the BZA 11 block of the intelligent interconnection terminal Inter 10, which gives a command in case of a short circuit in the contact network 6 to turn off the switch 5 with zero time delay. After disconnecting the latter, the UPKZ 13 unit connected to the voltage transformer, using the induced voltage, determines whether the short circuit disappeared in the disconnected contact network. If the short circuit disappeared, then the BZA 11 block executes a command to turn on the switch 5 with the shortest possible time delay. As indicated above, this is 0.6-0.7 seconds. Similarly, protection and automation work in case of short circuits in other parts of the contact network, while working similarly to the automation unit 14 of the switch 5, the automation units 15, 16, 17 of the switches 2, 3, 4.

Thus, with a short circuit at point 18, the circuit breaker 5 is disconnected from the protection without a time delay, the short circuit in the contact network is checked by the UPKZ 13 unit, and if the short circuit is passing, then a command is issued from the BZA 11 block to turn on the switch 5 by automatic reclosure with a minimum time delay of 0 , 6-0.7 sec. In this case, all electric locomotives will continue to move in the same mode.

As for the UKKZ 12 unit, it should also be included in the work together with the UPKZ 13 unit. If electric locomotives with phase splitters work, then when passing short circuit the reclosure will work from the UKKZ 12 block (usually the reclosure time from the UKPZ block is less than from the UKPZ block [ four]).

Note the distinctive features of the invention of alternating current:

1. The invention relates to a sectioning station with switches, individual protections and voltage transformers on the supply lines of the contact network.

2. The main protections are set to zero time delays.

3. When the monitoring devices detect a short circuit by induced voltage (CLC) of a passing short circuit (that is, the short circuit has disappeared), the Intel intelligent terminals issue a command to turn on the corresponding circuit breaker according to automatic reclosure after the minimum possible time of 0.6-0.7 sec.

Literature

1. German L.A., Zimakov V.A. Improvement of guidelines for relay protection of traction power supply of alternating current. Vestnik VNIIZHT, 2009 No. 5. S. 25-28.

2. Sectioning posts and parallel connection points. Schemes and technical parameters. NIIEFA-ENERGO. DIO Advertising Bureau, March 2011. 8 p.

3. Patent No. 160000 dated 10.28.2015. Section post for a contact AC network (German L.A. Korneev V.A., Popov D.S., Yakunin D.V.). Publ. 02/27/2016.

4. German L.A., German V.L. Automation of power supply of traction AC network M .: MIIT, 2014, 174 p.

5. STO RZD 07.021.1-2015. Protection of traction power supply systems of the railway from short circuits and overload. Part 1. General principles and rules for the construction of protections, interlocks and automation in traction power supply systems.

6. STO RZD 07.021.2-2015. Protection of traction power supply systems of the railway from short circuits and overload. Part 2. Methods for selecting action algorithms, lock settings and time delay automation in the traction power supply system.

Claims (1)

A method for partially non-selective protection of an alternating current traction network, comprising a sectioning station with switches, voltage and current transformers for each contact line supply line and smart terminals with a protection device and automatic reconnection of the emergency disconnected line supply of the sectioning station contact network, the main protections being zero time delay, characterized in that the absence of a short circuit is checked in the emergency disconnected contact network of means ohms of the short-circuit monitoring device according to the induced voltage, and in the absence of a short circuit, a command is issued to turn on the emergency-disconnected supply line with a minimum time delay by automatic restart.

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