CN206274500U - Earthed switch for drawing emergency electric supply unit - Google Patents

Abstract

The utility model relates to a grounding switch (1) for traction power supply equipment, the grounding switch (1) has a first main contact (3) and a movable second main contact (4), wherein, A movable second main contact (4) can be moved away from the first main contact (3) to form an air gap, characterized in that said main contacts (3, 4) have a pre-arcing device (5, 6), the pre-arcing device (5, 6) is suitable for short-circuit connection of the grounding switch. Furthermore, the invention relates to a method for grounding components of a traction power supply system by means of a grounding switch according to the invention.

Description

Earthing switch for traction power supply equipment

The invention relates to a grounding switch for traction power supply equipment.

Earthing switches are special switching devices which, in the simplest case, connect an electrical circuit to earth and thereby create a safe state. In the trolley wire network, the earthing switch is mainly used in stations and factories, and the automatic earthing switch is used for tunnel rescue. A system for automatic earthing is known, for example, from the document "Specifications for Automatic Earthing Equipment (AEE)" dated 18 April 2012 of the Swiss Railways (SBB CFF FFS), page 5. Further systems for automatic earthing are known from the magazine article "Trolley wire earthing—automation with Sicat AES" published in "Electrified Railway Special Issue (Elektrischen Bahnen Sonderdruck) S3/2013".

By the electronics factory Fritz Driescher & GmbH, 85366 Moosburg, Order No. 3-811201068.05-04 Open air circuit breakers of the series FlaV 25-2000-16-1B and 2B in the "Instructions for operation, installation and maintenance of Driescher open air switchgear for rail installations" It is known on page 9 to use so-called pre-starting angles for circuit breakers in order to improve the short-circuit making stability. As can be seen from Figure 11 on page 12 of the product description, the pre-starting angle is provided with a tip with a high temperature stability. Such a temperature-resistant tip has a low degree of wear during operation and thus reduces maintenance and repair costs. Temperature-stabilized tips are generally known in the prior art and are often produced from a tungsten alloy and welded to a pre-starting horn made of copper.

From page 3 of the 2013 document "Product Information/Version 1.2.0/Nr.A6Z00029955871", it is known that Siemens AG's earthing switch for traction power supply equipment with AC 25kV 8WL6144-1A is a grounding switch for traction power supply equipment , which has a first main contact and a second movable main contact, wherein the second movable main contact can be moved away from the first main contact in order to form an air gap. The earthing switch itself is classified according to criteria with regard to its short-circuit making category. Here, the grounding switch 8WL6144-1A is designed to be closed and then to establish a grounding state when the trolley wire is cut off in advance to ensure that it will not be connected again and check for no voltage. These measures prevent the earthing switch from being switched into a short-circuit state and thus being damaged or destroyed.

Furthermore, from this product information, a circuit breaker of the design series SICAT 8WL6144 from Siemens AG is known, which is equipped with an arcing horn made of copper. The burner element made of tungsten-copper alloy is welded on by the rather laborious Magna-Flash welding method. Consumable elements welded end-on the arcing corners must be replaced during maintenance work in the event of material erosion. Here, a new complete arcing horn is replaced and installed to ensure that the specified closing arc is extinguished.

The grounding switches for the AC and DC traction load current supply and which are to be connected to the live conductors must be short-circuit proof, in contrast to the known grounding switch 8WL6144-1A. Today, the switch is mainly characterized by the fact that the switching blades enter the contacts at a higher speed and thus in connection with the pre-strike when the momentary value of the current is lower. An example for this is the FES 3-20-1 B series from the company Driescher.

Rapid entry or rapid closing of the main contacts results in the known current-increasing effect, since the closing process must be within the time range of the lower region of the current increase in order not to impede the entry of the switching blade due to electrodynamic forces. However, compared to the switch series 8WL6144-1 from Siemens AG, said switch is more robust in construction and therefore more expensive due to its higher requirements. Although voltage checks according to the five safety regulations of EN50110 are now the standard before installing earthing switches, higher-level earthing switches with short-circuit making performance (such as AEE of the Swiss Federal Railways) are required. The reason for this is that in the event of an emergency shutdown there is no time for a voltage check and a safe state must be established within a few seconds. Other reasons may be misuse.

It is ignored here that a grounding switch, although triggering a short-circuit, then also withstands the short-circuit, but only when the supply circuit breaker detects by its short-circuit that it switches off the voltage in one or more substations and thus cuts off the short-circuit current. this load.

Starting from the known earthing switch of type 8WL6144-1A for traction power supply equipment, the technical problem to be solved by the present invention is to provide an earthing switch suitable for repeated short-circuit making, which can be manufactured at low cost .

According to the invention, the technical problem is solved by an earthing switch for a traction power supply system, which has a first main contact and a second movable main contact, wherein the second movable main contact can be moved from The first main contact is moved apart in order to form an air gap, which is characterized in that the main contact has a pre-arcing device which is suitable for short-circuit making of the earthing switch.

An advantage of the earthing switch according to the invention is that the functionality of the earthing switch is expanded compared to conventional earthing switches, since the short-circuit closing stability of the earthing switch according to the invention is greatly increased. This is achieved because the short circuit is not ignited via the main contacts, which prolongs the service life of the main contacts and at the same time ensures the relative integrity of the main contacts and the associated relatively reduced maintenance. The commutation via the pre-arcing device during the closing/switching-on movement ensures that the pre-arcing device triggers the short circuit as a "sacrificial element". The pre-arcing device can be easily repaired according to wear and tear, which provides cost advantages in the operation and maintenance of the earthing switch.

In this case, the earthing switch is relatively simple to construct, is based on the same platform concept as the disconnecting switch and the earthing switch and can be produced cost-effectively. Since the earthing switch is not damaged or damaged when the short-circuit is closed (in an emergency), it is particularly maintenance-free during operation.

The earthing switch according to the invention is suitable not only for direct current operation, but also for alternating current operation.

In a preferred embodiment of the earthing switch according to the invention, the pre-arcing device is arranged above the main contacts. This is advantageous because the protection of the main contacts is ensured because they are not located in the region of the thermal rise of the occurring arc column. This principle of minimization of the passing arc ensures that the bottom point of the arc always lies on the corresponding tip of the pre-starter provided for this purpose.

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

In this case, the pre-arcing device itself does not make contact, but is structurally designed in such a way that ignition caused by exceeding a critical field strength takes place reliably and leads to the formation of an arc. The distance between the pre-arcing installations is selected depending on the voltage system and the rated voltage. This embodiment of the pre-arcing device is advantageous because the corresponding losses due to the arcing in the area of the two main contacts occur only at the pre-arcing system provided for this.

In a further preferred embodiment of the earthing switch according to the invention, the pre-strike device is designed as a pre-strike angle. This is advantageous because the pre-starting angle is only designed and constructed for short-circuit making. In this way, the pre-starting angle is optimally configured for the acting load and is especially suitable for use on earthing switches.

According to a preferred refinement of the aforementioned embodiment, the pre-arcing angles are arranged substantially in a horizontal orientation and corresponding to the respective main contacts. This is advantageous because the arc generated in this way is only generated in the region of the pre-starting angle.

In a further preferred embodiment of the earthing switch according to the invention, the pre-arcing device is designed as an arcing corner.

This is advantageous because the striking angle is already known and proven from the use of circuit breakers which are supposed to simultaneously have a high breaking current carrying capacity. The use of the firing angle is particularly expedient when short-circuit switching stability is also required for load-break switches. In comparison, the pre-starting angle does not provide a high breaking current capability, so that this embodiment is particularly suitable for earthing switches with particularly high short-circuit stability.

In a further embodiment of the earthing switch according to the invention, the arcing horns are arranged in a substantially vertical orientation and assigned correspondingly to the main contacts. This is advantageous because the arc is thus only generated in the region of the striking angle. Due to the thermal floating effect, the arc is driven upwards along the striking angle and finally reaches the end of the striking angle intended for losses.

In a further preferred embodiment of the earthing switch according to the invention, the earthing switch is suitable for multiple short-circuit switching. The grounding switch according to the invention withstands one or more short-circuit closings, which is an advantage over known grounding switches, which are generally damaged due to short-circuiting. The earthing switch according to the invention is therefore particularly maintenance-free and short-circuit proof.

In a further preferred embodiment of the earthing switch according to the invention, the switching speed of the earthing switch is selected such that, before the main contact of the earthing switch contacts itself, the earthing A circuit breaker is provided capable of recognizing and breaking a short circuit formed by an arc on said pre-arcing device. So-called snap switches can also be used instead of circuit breakers.

This effect is achieved in that the circuit breakers present in the electrical traction power supply network are able to detect a short circuit, which occurs, for example, when an arc is generated at the pre-strike device. The circuit breaker then correspondingly interrupts the short circuit, so that when the main contacts are closed the arc is extinguished and the main contacts are de-energized. Circuit breakers and special fast switches can usually keep the tripping time of the protection and the switching off time of the current generally less than 100ms. The current loading of the main contacts of the earthing switch can therefore only occur in the event of a switching failure of the supplying circuit breaker. If the on-off failure of the circuit breaker, the backup protection will play a role. Typically in substations this results in triggering of circuit breakers on the input side. Although its pickup time is only 20ms, the total current passing time can be extended through other processing or synchronization time. This error is considered to have a very small probability for the already impossible event of being connected by a short-circuit of the grounding switch and has little effect in daily operation.

In the DC voltage range for high short-circuit currents, for example greater than 20 kA, the turn-off time is in the range of 20 ms to 30 ms. Typically, the current is even switched off in less than 20 ms.

Even in the AC voltage range, rapid shutdown for high short-circuit currents is a shutdown time in the range of 20 ms to 60 ms with an average disconnection time of 40 ms.

The opening time of the supplied circuit breaker is related to the current direction, the current increase and the measured loop impedance in addition to the current magnitude itself. However, these additional measurement value processing algorithms are only valid for lower amplitudes. In contrast, short circuits with higher magnitudes cause greater damage. The purpose of the impedance measurement is to detect a reliable short circuit in the entire associated switching assembly even for smaller short circuit currents and in the case of high variations in operating currents. This impedance level is usually accompanied by a delay time between 20ms and 30ms, so that the short-circuit current duration can reach a maximum of 100ms (20ms to 60ms+30ms).

From this simple estimation, the aforementioned estimation of the opening time of the circuit breaker of less than 100 ms results.

In this embodiment, therefore, the grounding switch is designed such that its closing speed is comparatively so slow that the corresponding arc is already safely interrupted by the circuit breaker before the main contacts close. Closing of the main contacts is preferably achieved after approximately 200 ms to 250 ms. Important for this embodiment is therefore the combination of the properties of the earthing switch according to the invention with the properties of conventional circuit breakers.

In the case of the grounding switch according to the invention, a simple and cost-effective solution for using the grounding switch with short-circuit making is achieved by means of a simple design compared to conventional grounding switches. A further advantage of this design is that it can be installed relatively simply from the perspective of the drive, since in particular the momentary switching function of the earthing switch based on the spring energy drive is not required in order to accelerate the closing process of the main contacts and thereby reduce the The load caused by an arc occurring.

In a further preferred embodiment of the earthing switch according to the invention, the pre-arcing device has a detachably mountable burner element.

This is advantageous because the consumable element can be mounted on the pre-arcing device and can be replaced easily without having to change the corresponding arcing angle of the pre-arcing device. This reduces costs not only in the production of the burner element but also in the maintenance of the pre-arcing device, since now only the burner element has to be replaced.

A further advantage is that a recalibration of the entire pre-arcing device does not have to be carried out when replacing the burner element, which saves time and costs in maintenance. In addition, the technical availability of the trolley wire system is increased.

In a preferred refinement of the aforementioned embodiment, the burner element has an internal thread and can be mounted on the pre-arcing device by means of a screw connection. The advantage of this screw connection is that, on the one hand, the screwing ensures a long-term secure locking of the burner element on the pre-arcing device, and on the other hand, the burner element can be easily replaced.

In a further preferred embodiment of the earthing switch according to the invention, the length of the burner element is determined as a function of the expected short-circuit switching frequency of the earthing switch. This is advantageous because a suitable length of the burner element can be selected depending on the requirements of the customer or the project in terms of the closing rate of the pre-arcing device, so that the burner element can be maintained without additional maintenance even when the burner element is highly loaded. set maintenance cycle.

In a further preferred embodiment of the earthing switch according to the invention, the burner element comprises a dispersion-strengthened copper material as material. This is advantageous, since in this way the switching off of the operating current can be optimized. The burner element made of dispersion-strengthened copper has a higher temperature resistance and thus a higher arc resistance than pure copper, which allows the pre-arcing device to last longer without maintenance time availability. A further advantage is that the consumption element produced from the dispersion-strengthened copper material is also significantly cheaper to purchase than the known tip produced from tungsten.

The material is produced powder metallurgically by means of reactive coatings; for example, the CEP DISCOP high-performance copper material from the company Compound Extrusion Products GmbH in Freiberg (instruction manual 09/09) is known. The use of this heat-resistant material is advantageous because it reduces the frequency of maintenance on the burn-up element.

Furthermore, the advantage of using dispersion-strengthened copper materials is that they are characterized by high damage strength and high temperature resistance. For example, the heat-resistant copper material is such a dispersion-strengthened copper material, only when the dispersion-strengthened copper material is heated at a temperature higher than 800 ° C for one hour beforehand, the dispersion-strengthened copper material has a particularly significant effect at 20 ° C after cooling. Reduced hardness. Such a dispersion-strengthened copper material with particularly high heat resistance is known, for example, from the alloys CEP DISCOPC3/11 and C3/80 of the company Compound Extrusion Products GmbH in Freiberg (instruction manual 09/09).

Here, dispersion-strengthened copper materials are suitable for machining. This is advantageous because such dispersion-strengthened copper materials can be machined very well and can be machined into short and uniform chip shapes. In contrast, known tungsten copper materials cannot be machined due to their hardness. The machinable machining of the dispersion-strengthened copper material makes it possible, for example, to form cavities and, if necessary, internal threads during the production process in order to be able to detachably mount the burner element afterwards.

Furthermore, the subject matter of the invention also includes a method for grounding components of a traction power supply system by means of the grounding switch according to the invention, the method comprising the steps of:

- under the voltage carried by the parts of the traction power supply equipment, the ignition switch is on when the earthing switch is closed

the arc that constitutes a short circuit through the pre-strike device, and

- The short circuit is switched off by means of the circuit breaker present in the traction power supply, de-energizing the main contacts of the earthing switch before they make contact.

Similarly, the method according to the invention has the same advantages as explained in the introduction for the earthing switch according to the invention.

Embodiments according to the invention are schematically shown in the drawings, where

FIG. 1 shows a first embodiment of an earthing switch according to the invention at different points in time during the closing process and

Figure 2 shows an example of a traction power supply with a circuit breaker and a grounding switch.

FIG. 1 shows an earthing switch 1 for a traction power supply system, which has a first main contact 3 and a second movable main contact 4 . The main contact 3 is at a distance from the base plate 8 of the earthing switch 1 on the lever 9 . Arranged above the first main contact 3 is a pre-starting angle 5 , which points in a substantially horizontal orientation in the direction of the second main contact 4 . The movable second main contact 4 is arranged on the second rod 11 with the insulator element 7 and can be moved away from the first main contact 3 in order to form an air gap by deflecting the second main contact 4 via the hinge 10 . In this case, the pivoting movement is carried out by a drive, not shown, which engages on the lever 11 with the second lever 11 . Arranged above the second main contact 4 is a pre-starting angle 5 which points in a substantially horizontal orientation in the direction of the first main contact 3 . The two pre-arcing angles 5 , 6 jointly form the pre-arcing devices 5 , 6 of the earthing switch 1 .

In FIG. 1A the grounding switch 1 is open, and an air gap is formed between the main contacts 3 , 4 and the pre-starting angles 5 , 6 . In this state the grounding switch 1 is open.

In FIG. 1B the grounding switch 1 is shown at a point in time during the closing process, the air gap between the main contacts 3 , 4 and the pre-starting angles 5 , 6 has become significantly shorter. The main contacts 3, 4 are still separated, but the pre-arcing angles 5, 6 themselves are already so close that an arc forms between them in the event of a short circuit. The state shown with arc formation is generally established 100 ms after the start of the closing process.

Generally, the presence of an arc causes the associated circuit breaker (not shown) to detect the short circuit and switch off immediately. In this way, the arc present between the pre-starting angles 5 , 6 is extinguished before the earthing switch 1 reaches the closed state of the main contacts 3 , 4 shown in FIG. 1C . The losses caused by the arc are only in the region of the pre-starting angles 5, 6, so that after repeated loads due to the short-circuit switching of the earthing switch 1 only the pre-starting angles have to be replaced, which is comparatively low cost and can be implemented quickly.

FIG. 2 shows a power supply device 20 for traction, which has a first trolley wire 21 corresponding to the first rail and a second trolley wire 22 corresponding to the second rail. The track section can thus be driven on both sides. The two conductor lines 20 , 21 are each supplied in sections by a substation 34 , which each has a circuit breaker or quick switch 36 for supplying the supply section of the conductor lines. A disconnect switch 37 is respectively connected between the circuit breaker or quick switch 36 and the trolley wires 21 , 22 ; a disconnect switch of the type 8WL8134-4 from Siemens AG, for example, is used here. The supply section is predetermined by a disconnection point 41 , wherein the symbol "operating limit" 8 marks this area. Furthermore, an earthing switch 39 according to FIG. 1 is provided for earthing the conductor lines 20 , 21 .

One of the transformer substations 35 has a data processing center 15 and is provided for exchanging measured data of the state of the electric traction power supply network and the supply section with the other transformer substation 4 via a communication line 33 .

All substations 34 , 35 are connected to a communication network 32 via a communication line 33 , which is connected to a higher-level dispatcher such as a supervisory control and data acquisition (SCADA) system 31 .

The circuit breaker or snap switch 36 has to detect a short circuit and switch off the voltage on the basis of the protective device assigned to it. A synchronous circuit of one or more grounding switches 39 to one or more supplying circuit breakers 36 is absent and unnecessary.

Switches that require a short-circuit making function must be constructed differently.

The switch features a momentary switch or snap switch function for fast contact movement. The structural solution is a switch of the type FES 3-20-1 B from the company Driescher. If, for the requirement of short-circuit making, a disconnect switch which does not have this design requirement is used, the contacts will generally be thermally overloaded and destroyed. The reason for this is that the drive of the contacts is a slow-action drive, which moves the moving switching contact too slowly and thus makes the resulting arc stay too long and is often additionally blocked at the inlet by the electromotive forces acting on it. The function generally used for the short-circuit making stability of the product is demonstrated by type tests. In this case, the current duration is between 250 ms (for a DC voltage electrical traction supply network) and 1000 ms (for an AC voltage electrical traction supply network). However, this time does not correspond to actual actual conditions but includes a safety factor. As mentioned above, locking prevents live conductors from being switched on and only occurs in emergency or exceptional situations. One can infer that the switching frequency of this switch is very small. The repeated or multiple functions of "wrong switching" more than twice are not provided or are not necessary without maintenance.

The grounding switch 39 according to the invention provides a solution with a relatively simple design, which can be produced inexpensively and requires little maintenance.

Claims (13)

1. a kind of earthed switch (1) for drawing emergency electric supply unit, the earthed switch (1) with the first main contacts (3) and Movable second main contacts (4), wherein, movable second main contacts (4) can be removed to constitute from the first main contacts (3) The air gap, it is characterised in that the main contacts (3,4) with pre- arc starter (5,6), fit by the pre- arc starter (5,6) For the short circuit making of the earthed switch.

2. according to the earthed switch (1) described in claim 1, it is characterised in that the pre- arc starter (5,6) is arranged in described Main contacts top.

3. according to the earthed switch (1) described in claim 1 or 2, it is characterised in that the pre- arc starter (5,6) is for every Individual contact all has a pre- starting the arc facility.

4. according to the earthed switch (1) described in claim 3, it is characterised in that the pre- starting the arc facilities design plays arc angle for pre-.

5. according to the earthed switch (1) described in claim 4, it is characterised in that the pre- arc angle is substantially determined by horizontal To arrangement and arranging corresponding with each main contacts (3,4).

6. according to the earthed switch (1) described in claim 3, it is characterised in that the pre- starting the arc facilities design is arcing horn.

7. according to the earthed switch (1) described in claim 6, it is characterised in that the arcing horn substantially presses vertical orientation Arrangement and arranging corresponding with each main contacts (3,4).

8. according to the earthed switch (1) described in preceding claims 1, it is characterised in that the earthed switch (1) is suitable for repeatedly Carry out short circuit making.

9. according to the earthed switch (1) described in claim 8, it is characterised in that the selection of the closing speed of the earthed switch is, The earthed switch (1) the main contacts (3,4) contact before, by electric railway power supply network with the earthed switch (1) breaker that correspondence is arranged is capable of identify that and disconnects the short circuit formed by the electric arc on the pre- arc starter (5,6).

10. according to the earthed switch (1) described in preceding claims 1, it is characterised in that the pre- arc starter (5,6) has The burnup element that can removably install.

11. according to the earthed switch (1) described in claim 10, it is characterised in that the burnup element have internal thread and Can be arranged on the pre- arc starter according to bolted mode.

12. according to the earthed switch (1) described in claim 10 or 11, it is characterised in that short according to expected from earthed switch The length that frequency determines burnup element is connected on road.

13. according to the described earthed switch of one of claim 10 to 11 (1), it is characterised in that the burnup element is used as material Material includes the copper product of dispersion-strengtherning.