EP3074998A2

EP3074998A2 - Earthing switch for traction power supply systems and method for earthing a part of a traction power supply system using an earthing switch

Info

Publication number: EP3074998A2
Application number: EP15700853.3A
Authority: EP
Inventors: Andre DÖLLING; Sonja Leistner; Philippe Leray
Original assignee: Siemens AG
Current assignee: Siemens Mobility GmbH
Priority date: 2014-01-31
Filing date: 2015-01-09
Publication date: 2016-10-05
Anticipated expiration: 2035-01-09
Also published as: DE102014201809A1; WO2015113794A2; WO2015113794A3; CN206274500U; EP3074998B1

Abstract

The invention relates to an earthing switch (1) for traction power supply systems (2), comprising a first main contact (3) and a movable second main contact (4), wherein the movable second main contact (4) can move away from the first main contact (3) to create a clearance, characterised in that the main contacts (3, 4) have a pre-ignition arrangement (5, 6) which is suitable for ensuring the short-circuit making capacity of the earthing switch (1). The invention also relates to a method for earthing a part of a traction power supply system using an earthing switch according to the invention.

Description

description

Earthing switch for traction current systems and method for grounding a part of a traction current system by means of a grounding switch

Earthing switches are special switching devices that in the simplest case connect an electrical line to ground and thus establish a safe state. In overhead catenary systems, earthing switches are mainly used in halls and factories and automated grounding systems for tunnel rescue. An automated grounding system is known, for example, from the SBB CFF FFS Specifications Manual of 18 April 2012 on page 5. Another system for automated grounding is Sicat AES from the journal article "Catenary Grounding - Automated with Sicat AES It is from the product description of the outdoor circuit-breaker of the FLaV 25-2000-16-1B and 2B series, on page 9 of the "Operating, Installation and Maintenance Instructions for Driescher Freiluft Schaltgeräte für Bahnanlagen ", order number 3-811201068.05-04 by Elektrotechnische Werke Fritz Driescher & Söhne GmbH, 85366 Moosburg, Germany, is known to use so-called pre-ignition horns for switch-disconnectors to improve the short-circuit breaking strength. Fig. 11 on page 12 of the same product description shows that the pre-ignition horns are equipped with a tip that is particularly temperature-stable. Such temperature-resistant tips have a particularly low wear during operation and thus reduce maintenance and repair costs. The temperature stable tips are well known in the art and are often fabricated from tungsten alloys and welded to the pre-ignition horns made of copper.

Earthing switch 8WL6144-1A for AC 25 kV traction current systems of Siemens AG, known from "ProductInformation / Version 1.2.0 / No. A6Z00029955871 "from 2013 on page 3, is a grounding switch for railway power plants having a first main contact and a movable second main contact, the movable second main contact being movable away from the first main contact to establish an air gap The earthing switch 8WL6144-1A is a grounding switch whose design is only then closed and thus produces a grounded state if the catenary was previously switched off, secured against being switched on again and tested for absence of voltage These measures prevent the earthing switch from switching to a short circuit - which would damage or destroy it.

It is also known from the same product information of the SICAT 8WL6144 series of Siemens AG circuit breakers, in which arc horns made of copper are provided. In the relatively complex Magna Flash welding process, burn-off elements are welded from a tungsten copper alloy. The butt welded to the arcing horns consumables must be replaced during erosion of the material in the course of maintenance. The entire arc horns are exchanged and realigned so that the envisaged switching arc quenching is ensured.

Earthing switches, which are used for AC and DC traction power supply and are to be connected to a live line, must, in contrast to the known earthing switch 8WL6144-1A, be short-circuited. These switches are characterized today primarily by the fact that the switching blade enters the contact at a high speed and thus in connection with the preheating an inlet into the contact at a low instantaneous value of

Electricity takes place. Examples are z. B. switches of the series FES 3-20-1 B Fa. Driescher. The rapid entry or the rapid closing of the main contacts results in the known effect of the current increase, because the closing process must remain in the time range of the lower portion of the current rise, so as not to be hindered by the current forces at the inlet of the switch blade. However, the switches mentioned are compared to the switch series

8WL6144-1 Siemens AG built by the higher requirements comparatively robust and therefore more expensive. Although the voltage test according to the five safety rules according to EN 50110 is standard today before the earthing switch is inserted, earthing switches of the higher category with short-circuit breaking capacity are nevertheless required (for example AEE of the Swiss Federal Railways). This is justified by the fact that in cases of emergency shutdown there would be no time for a voltage test and within a few seconds a safe state must be established. Other reasons could be incorrect operation.

It is forgotten that a grounding switch triggers and subsequently carries the short-circuit, but this earthing switch can withstand this load only if the supplying circuit-breaker switches off the voltage and thus the short-circuit current in the substation or substations via its short-circuit detection.

Starting from the well-known earthing switch for type 8WL6144-1A traction current systems, it is an object of the invention to provide a grounding switch which is suitable for repeated short-circuit closing and which can be produced inexpensively.

This object is achieved according to the invention by a earthing switch for traction current systems having a first main contact and a movable second main contact, the movable second main contact being movable away from the first main contact for producing an air gap, characterized in that the main contacts comprise a pre-ignition arrangement. which is suitable for a short-circuit closing of the earthing switch.

It is an advantage of the earthing switch according to the invention that the functionality of the earthing switch is widened in comparison to conventional earthing switches, because the short-circuit breaking capability of the earthing switch according to the invention is considerably increased. This is achieved because the short circuit is not ignited through the main contacts, which extends the life of the main contacts while ensuring relative integrity and, associated therewith, a relative low maintenance of the main contacts. The current transfer via the Vorzündanordnung during the

Closing movement / switch-on movement ensures that the pre-ignition arrangement triggers the short-circuit as a "victim element". The Vorzündanordnung can easily be repaired depending on the wear, which offers cost advantages in terms of operation and maintenance of the earthing switch. The earthing switch is comparatively simple in design, uses the same platform concept for existing disconnectors and earthing switches and is inexpensive to manufacture. During operation, the earthing switch is particularly low maintenance because it is not damaged or destroyed in the event of a short circuit (in emergency situations).

The earthing switch according to the invention is suitable for applications in both DC and AC operation.

In a preferred embodiment of the earthing switch according to the invention, the pre-ignition arrangement is arranged above the main contacts. This is advantageous because a protection of the main contacts is ensured because the main contacts are not in the range of thermal buoyancy occurring

Arc column lie. This ensures via the minimum principle of the arc, that its bases always on the appropriate, provided for this purpose tips Vorzundanordnung.

In a further preferred embodiment of the earthing switch according to the invention, the preheating arrangement has a pre-ignition device for each main contact.

The Vorzündeinrichtungen do not touch, but are designed so constructive that an ignition is done safely by exceeding a critical field strength and leads to the formation of an arc. The distance between the pre-ignition devices is selected as a function of the voltage system and the rated voltage. This embodiment of the pre-ignition arrangement is advantageous because corresponding wear due to arcing in the region of both main contacts only occurs at the pre-ignition devices provided for this purpose.

In another preferred embodiment of the earthing switch according to the invention, the pre-ignition devices are designed as pre-ignition horns. This is advantageous because pre-ignition horns are designed and designed only for short circuit switching. This pre-ignition horns are well designed for the loads acting and especially suitable for use with earthing switches.

According to a preferred development of the aforementioned embodiment, the pre-ignition horns are mounted essentially in horizontal alignment and assigned to the respective main contact. This is an advantage because arcing in this way occurs only in the area of the pre-ignition horns.

In a further preferred embodiment of the earthing switch according to the invention, the pre-ignition devices are designed as arcing horns.

This is an advantage because arcing horns, when used with circuit breakers, schaltstrombelastbarkeit have long been known and tested. The use of arcing horns is particularly useful if a short-circuit withstand voltage is required for load-break switches. A high breaking current capacity can not be afforded by the pre-ignition horns in comparison, so that this embodiment is particularly suitable for earthing switches with a particularly high short-circuit resistance. In another preferred embodiment of the earthing switch according to the invention, the arc horns are mounted substantially in vertical alignment and associated with the respective main contact. This is an advantage because arcs are created exclusively in the area of the arcing horns. These arcs are driven by the thermal buoyancy up along the arc horns and eventually reach the ends of the arc horns that are intended for wear. In a further preferred embodiment of the earthing switch according to the invention, the earthing switch is suitable for making a short-circuit closing several times. A grounding switch according to the invention can withstand single or multiple switching on of a short circuit, which is an advantage over known earthing switches, which are usually damaged by short-circuit closing. The grounding switch according to the invention is therefore particularly low maintenance and short-circuit protection. In a further preferred embodiment of the grounding switch according to the invention, the turn-on speed of the earthing switch is selected such that a short circuit with arcing at the Vorzündanordnung by means of a power switch assigned to the earthing switch in the traction current switch can be seen and switched off before the

Touch the main contacts of the earthing switch. Instead of a circuit breaker and a so-called quick switch can be used. This effect is achieved by virtue of the fact that circuit breakers present in a traction current network can detect a short circuit, as it exists at the pre-ignition arrangement when an arc occurs. The circuit breakers would then break the short circuit accordingly, so that when

Close the main contacts already the arc extinguished and the main contacts are de-energized. Circuit breakers, as well as special high-speed switches, are generally capable of maintaining a tripping and power-off time of typically less than 100 ms. A current load of the main contacts of the earthing switch would therefore only occur in the event of a switching failure of the power circuit breakers. If a switching failure of a circuit breaker occurs, a backup protection is activated. In the substations, this usually causes the circuit breaker to trip on the input side. Although their switching times are only 20 ms, the total current flow time can be extended by further processing or transfer times. These errors are to be set for an already unlikely event of a Kurzschlusseinschaltung by the earthing switch with an extremely low probability and play little role in everyday life. In the DC voltage range are shutdown times for high

Short circuit currents of, for example, more than 20 kA in the range of 20 to 30 ms. Frequently, even currents are switched off within less than 20 ms. Even in the AC voltage range today is spoken in an emergency shutdown for high short-circuit currents over shutdown times in the range of 20 to 60 ms with a mean turn-off of 40 ms. The turn-off time of a power circuit-breaker depends not only on the current amplitude but also on the direction of current flow, the current increase and the measured loop impedance. These additional measurement processing algorithms will be but effective only for lower amplitudes. Otherwise, the short circuit with high amplitudes would cause greater damage. The aim of the impedance measurements is the safe short-circuit detection in the entire associated switching group, also for lower short-circuit currents and the distinctiveness of high operating currents. These impedance stages generally entail between 20 and 30 ms delay time, so that the short-circuit current flow duration up to max. 100 ms (20 ms to 60 ms + 30 ms).

From this simple rough calculation results the aforementioned estimate of less than 100 ms shutdown time of a circuit breaker. The earthing switch is therefore designed in this embodiment that its closing speed is relatively slow so that a corresponding arc is already safely shut down by a circuit breaker before the main contacts close. Closing of the main contacts is preferably achieved after about 200 to 250 ms. It is therefore essential for this embodiment, the combination of the properties of the earthing switch according to the invention with the properties of common circuit breakers. Thus, a simpler and more cost-effective solution for applications of a grounding switch with Kurzschlusseinschaltung is possible with the grounding switch according to the invention by a simple design solution over previous earthing switches. Another advantage of this design is to be relatively simple in design from the drive, because in particular no snap-action function of the earthing switch is required based on spring drives to accelerate the closing operation of the main contacts and thus reduce the burden of an occurring arc. In a further preferred embodiment of the earthing switch according to the invention, the burn-up elements that can be detachably attached to the pre-ignition arrangement have. This is an advantage because the Abbrandelemente can be attached to a Vorzündanordnung and easily replaced without the corresponding arc horns of Vorzündanordnung must be replaced. As a result, both in the production of Abbrandelemente and in the maintenance of Vorzündanordnung costs, since now only the Abbrandelemente must be replaced.

Another advantage is that when replacing the Abbrandelemente no readjustment of the entire Vorzündanordnung must be done, which saves time and costs in maintenance. Furthermore, the technical availability of the catenary system is increased.

In a preferred development of the abovementioned embodiment, the burn-off elements have an internal thread and can be attached to the pre-ignition arrangement in the manner of a screw connection. Such a screw connection is advantageous in that on the one hand a long-term secure locking of the Abbrandele- ment is ensured on the Vorzündanordnung by the screw and on the other hand, the Abbrandelement can be easily replaced.

In another preferred embodiment of the grounding switch according to the invention, the length of the burn-off elements is dimensioned according to an expected short-circuit turn-on frequency of the grounding switch. This is an advantage because depending on customer or project requirements with respect to the switching frequency of Vorzündanordnung a Abbrandelement suitable length can be selected to comply, for example, a predetermined maintenance interval even with heavy use of Abbrandelemente without additional maintenance. In another preferred embodiment of the earthing switch according to the invention, the burn-off elements comprise as material a dispersion-hardened copper material. This is an advantage because it can optimize the switching off of operating currents. The Abbrandelemnte from dispersion-strengthened copper material have compared to pure copper on a higher temperature and thus arc resistance, resulting in a longer usability of the Vorzündanordnung without maintenance costs. Another advantage is that the Abbrandelemente of dispersion strengthened copper material compared to known tips made of tungsten are also priced significantly cheaper in purchasing.

The preparation of this material is powder metallurgically by reaction times; For example, CEP DISCOP high-performance copper materials from Compound Extrusion Products GmbH in Freiberg are known (application brochure 09/09). The use of this refractory material is advantageous because it reduces the frequency of maintenance of the consumable elements.

The use of dispersion-strengthened copper material is furthermore advantageous in that it is characterized by high wear resistance and high temperature resistance. Examples of a heat resistant

Copper materials are dispersion-hardened copper materials, which in particular have a substantially reduced hardness at 20 ° C. after cooling only when the dispersion-strengthened copper material was previously heated to above 800 ° C. for 1 hour. Such a dispersion-hardened copper material with a particularly high heat resistance is known, for example, from the alloys CEP DISCOP C3 / 11 and C3 / 80 from Compound Extrusion Products GmbH in Freiburg (application brochure 09/09).

The dispersion-hardened copper material is suitable for machining. This is an advantage because such dispersion strengthened copper materials are excellent are machinable and can be formed by short and uniform chip formation. Known tungsten copper materials, by comparison, can not be machined due to their hardness. The machinability of the dispersion-strengthened copper materials allows, for example, in the production process, the formation of a cavity and possibly an internal thread in order to attach the Abbrandelement later detachable can. Furthermore, the subject of the present invention is a method for grounding a part of a traction current system by means of a grounding switch according to one of the preceding claims, comprising the steps:

- When voltage applied to the part of the traction current system, a short-circuit on the Vorzündanordnung forming arc is ignited when closing the earthing switch and

- The short circuit is switched off by existing in the traction current circuit breaker, so that the main contacts of the earthing switch are de-energized before their contact.

The same advantages as described in the introduction for the earthing switch according to the invention are obtained analogously for the method according to the invention.

Embodiments of the invention are shown schematically in the figures, in which shows

1 shows a first embodiment of the inventive earthing switch at different times of the switch-on and

2 shows an example of a traction current system with power and grounding switches.

FIG. 1 shows a grounding switch 1 for traction current systems with a first main contact 3 and a movable second main contact 4. The main contact 3 is at a Rod 9 spaced from a base plate 8 of the earthing switch 1. Above the first main contact 3, a pre-ignition horn 5 is arranged which points in a substantially horizontal orientation towards the second main contact 4. The movable second main contact 4 is arranged on a second rod 11 with an insulator element 7 and can be moved away from the first main contact 3 to produce an air gap by tilting it over a tilting joint 10. The tilting movement is carried out via a drive, not shown, which acts on a lever 11 to the second rod 11. Above the second main contact 4, a Vorzündhorn 5 is arranged, which points in a substantially horizontal orientation to the first main contact 3 out. The two pre-ignition horns 5, 6 together form the pre-ignition arrangement 5, 6 of the grounding switch 1.

In Figure la, the earthing switch 1 is opened, so that a

Air gap between the main contacts 3,4 and the Vorzünd- horns 5,6 is formed. The earthing switch 1 is turned off in this state.

In Figure lb the earthing switch 1 is shown at a time during the closing process, so that the air gap between the main contacts 3,4 and the Vorzündhörnern 5.6 is already significantly shortened. The main contacts 3,4 are still separated, but the pre-ignition horns 5,6 are already so close that an arc is formed between them in the event of a short circuit. The illustrated state with arcing is typically 100 ms after the beginning of the arc

Closing settled.

An existing arc typically causes an associated circuit breaker (not shown) to detect the short circuit and quickly shut down. In this way, an existing arc between the pre-ignition horns 5, 6 is already extinguished before the grounding switch 1 reaches the closed state of the main contacts 3, 4 shown in FIG. 1c. An induced by the arc wear is So only in the area of the pre-ignition horns 5.6 to be expected, so that after a multiple stress by Kurzschlusseinschaltungen the earthing switch 1, only the Vorzündhörner must be replaced, which can be comparatively cost-effective and quickly performed.

2 shows a traction current system 20 with a first contact line 21, which is associated with a first track, and a second contact line 22, which is assigned to a second track. The railway line is thus passable on both sides.

The two catenary lines 20,21 are each fed in sections by a substation 34, each having power or quick switch 36 for feeding a supply section of a catenary. Between performance or

Quick switch 36 and catenary 21,22 each disconnector 37 are connected; For example, 8WL8134-4 circuit breakers from Siemens AG are used. The feed sections are defined by separation points 41, whereby signs "working limit" 8 characterize these areas .Overhead earthing switches 39 according to FIG. 1 are furthermore provided for earthing the contact lines 20, 21.

One of the substations 35 has a data processing center 15 and is set up to exchange measurement data on the state of the electric traction current network and of the feed sections with the other substations 4 via communication lines 33.

All substations 34, 35 are connected via communication lines 33 to a communications network 32 which is connected to a higher-level control center, such as a Supervisory Control and Data Acquisition (SCADA) system 31.

The power or quick switches 36 must detect a short circuit on the basis of their own assigned protection and switch off the voltage. An entrainment circuit of one or more earthing switches 39 to one or more power circuit breakers 36 is not existent and necessary. Switches for which the short-circuit switching function is required must be designed differently. Characteristic of this switch is a kind of snap-action or quick-switching function to achieve a rapid contact movement. Constructive solutions are shown above switch type FES 3-20-1 B of the company Driescher. If a circuit breaker without such design requirements is used for requirements after short-circuit closing, the contact is usually thermally overloaded and destroyed. This is due to the fact that the drive of the switch as a crawl drive moves the movable switching contact too slowly and thus the resulting arc is too long and is often prevented in addition by the effective current forces at the entry. Type testing usually proves the function of the short-circuit withstand capability for the product. The current flow duration in these cases is between 250 ms for

DC traction current systems and 1000 ms for AC railway systems. However, these times do not correspond to the real practice conditions but contain security surcharges. As already stated, the connection of a live overhead line by interlocks is avoided and occurs only in emergencies or exceptional situations. It can be deduced that the frequency of such circuits is very low. A repeated or repeated function of more than two "faulty circuits" without maintenance is not given or necessary. The earthing switch 39 according to the invention offers a comparatively simply constructed solution which is inexpensive to manufacture and requires little maintenance.

Claims

claims

A grounding switch (1) for traction current installations having a first main contact (3) and a movable second main contact (4), wherein the movable second main contact (4) is movable away from the first main contact (3) to establish an air gap,

d a d u r c h e c e n c i n e s that

the main contacts (3, 4) have a pre-ignition arrangement (5, 6) which is suitable for a short-circuit closing of the grounding switch.

2. earthing switch (1) according to claim 1,

d a d u r c h e c e n c i n e s that

the Vorzündanordnung (5,6) is arranged above the main contacts.

3. earthing switch (1) according to claim 1 or 2,

d a d u r c h e c e n c i n e s that

the pre-ignition arrangement (5, 6) has a pre-ignition device (5, 6) for each main contact.

4. earthing switch (1) according to claim 3,

d a d u r c h e c e n c i n e s that

the pre-ignition devices (5, 6) are designed as pre-ignition horns (5, 6).

5. earthing switch (1) according to claim 4,

d a d u r c h e c e n c i n e s that

the pre-ignition horns (5, 6) are mounted essentially in a horizontal orientation and assigned to the respective main contact (3, 4).

6. earthing switch (1) according to claim 3,

d a d u r c h e c e n c i n e s that

the pre-ignition devices (5, 6) are designed as arcing horns.

7. earthing switch (1) according to claim 6,

d a d u r c h e c e n c i n e s that

the arcing horns are mounted essentially in vertical alignment and assigned to the respective main contact (3, 4).

8. Earthing switch (1) according to one of the preceding claims,

d a d u r c h e c e n c i n e s that

the earthing switch (1) is suitable for multiple short-circuit closing.

9. earthing switch (1) according to claim 8,

d a d u r c h e c e n c i n e s that

the turn-on speed of the earthing switch is selected such that a short circuit with arcing at the Vorzündanordnung (5,6) by means of a in the traction current network the earthing switch (1) associated circuit breaker can be recognized and switched off before the main contacts (3,4) of the earthing switch (1 ) touch.

10. Earthing switch (1) according to one of the preceding claims,

d a d u r c h e c e n c i n e s that

the Vorzündanordnung (5,6) releasably attachable Abbrandelemente.

11. earthing switch (1) according to claim 10,

d a d u r c h e c e n c i n e s that

the Abbrandelemente have an internal thread and can be attached to the Vorzündanordnung in the manner of a screw connection.

12. earthing switch (1) according to claim 10 or 11,

d a d u r c h e c e n c i n e s that

the length of the burn-off elements is dimensioned according to an expected short-circuit turn-on frequency.

13. Earthing switch (1) according to claim 10, wherein:

the burn-off elements comprise as material a dispersion-hardened copper material.

14. A method for grounding a part of a traction current system by means of a grounding switch (1) according to one of the preceding claims, comprising the steps:

- When voltage applied to the part of the traction current system when closing the earthing switch (1) a short circuit on the Vorzündanordnung (5.6) forming arc ignited and

- the short-circuit is switched off by circuit-breakers in the traction current system, so that the main contacts (3, 4) of the earthing switch (1) are de-energized before being touched.