Sensor system and on-load tap changer device for determining duration of arc combustion

Abstract

The invention relates to a sensor system (20) for determining an arc combustion duration in a vacuum interrupter (4), comprising: a measuring device (5) having a receiver (16) and a measuring device (18); a sensor unit (10) having a voltage divider (11), an energy generator (12), an energy conversion unit (13), an evaluation unit (14) and a transmitter (15); wherein the sensor unit (10) can be connected to a first contact (4.1) and a second contact (4.2) of the vacuum switching tube (4); the sensor unit (10) is connected to the measuring device (5) via a signal transmitter (17).

Description

Technical Field

[0001] The invention relates to a sensor system for determining the burning duration of an arc and to an on-load tap changer device. Background Art

[0002] On-load tap changers are used to switch between different winding taps of electrically operated components (e.g. power transformers or adjustable chokes) without interruption. Since switching elements, such as vacuum switching tubes and selector arms, are always at high voltage potential, these components are generally not monitored. However, devices and methods for monitoring these components are still desired. Summary of the invention

[0003] It is therefore an object of the present invention to provide a sensor system which allows precise and cost-effective monitoring of vacuum switching tubes.

[0004] This object is achieved by the respective subject matter of the independent claims. Further embodiments are the subject matter of the dependent claims.

[0005] The present invention proposes a sensor system for determining the arc burning duration in a vacuum switching tube, comprising:

[0006] - a measuring device having a receiver and a measuring device;

[0007] - a sensor unit having a voltage divider, an energy generator, an energy conversion unit, an evaluation unit and a transmitter;

[0008] in,

[0009] - the sensor unit can be connected to a first contact and a second contact of the vacuum interrupter;

[0010] - The sensor unit is connected to the measuring device via a signal transmitter.

[0011] By connecting the sensor unit directly to the vacuum switching tube, the arc burning duration can be determined. In this case, when an arc is generated in the vacuum switching tube, the voltage divider of the sensor unit detects the voltage applied to the vacuum switching tube or taps off the voltage applied to the vacuum switching tube. The detected arc is transmitted as an output signal to the measuring device via the evaluation unit and the transmitter and evaluated by the measuring device. From the duration of the output signal, the duration of the arc burning duration can be inferred. The sensor unit is autonomously powered by the energy generator. This is particularly advantageous because the sensor unit is at a high voltage potential. No expensive wiring for the energy supply is required.

[0012] The transmitter and the receiver can be designed in any manner, for example, the transmitter can be configured as a diode and the receiver can be configured as a photodiode. In this embodiment, the signal transmitter is configured as an optical waveguide. In addition, the signal transmission can be realized in any manner depending on the configuration of the transmitter, the receiver and the signal transmitter, for example by radio, Bluetooth, WLAN, etc.

[0013] The energy generator can be implemented as a current converter or voltage converter or a converter according to the energy harvesting principle, for example. It is preferably arranged within the tap transformer, preferably at a high voltage potential.

[0014] Furthermore, the evaluation unit can be designed as a rectifier network. The evaluation unit is preferably connected to the energy generator via the energy conversion unit in order to supply energy to the sensor unit. The voltage divider of the sensor unit is connected to the first contact and the second contact of the vacuum switching tube for detecting the arc burning duration.

[0015] The sensor unit is designed and provided for connection to a vacuum switching tube of the on-load tap changer, the sensor unit is in particular designed and provided for connection to a first and a second contact of the vacuum switching tube.

[0016] The vacuum switching tube can be designed in any manner and have a first contact and a second contact. These contacts extend outward from the interior of the vacuum switching tube. In this case, the sensor unit can be connected directly to the contacts of the vacuum switching tube or by means of a conducting element, such as a cable, which is connected to the contacts.

[0017] In addition, the present invention provides an on-load tap changer device, comprising:

[0018] - On-load tap-changers with vacuum switching tubes;

[0019] - a sensor system having a measuring device and a sensor unit for determining the burning duration of an arc in a vacuum interrupter;

[0020] in,

[0021] - the sensor unit is connected to a first contact and a second contact of the vacuum interrupter;

[0022] - The measuring device is connected to the sensor unit via a signal transmitter.

[0023] The on-load tap changer device makes it possible to determine the arc burning duration within the vacuum switching tube of the on-load tap changer. It can thus be ensured that the arc within the on-load tap changer is extinguished during actuation. In addition, the actuation of the on-load tap changer via the drive can be adjusted based on this information so that the arc burning duration is as short as possible. Due to the arrangement of the sensor unit in the immediate vicinity of the vacuum switching tube, the on-load tap changer device is particularly compact. In addition, the energy supply of the sensor unit is achieved in an autonomous manner by means of a dedicated energy generator.

[0024] In addition, the on-load tap changer device has a drive for operating the on-load tap changer, wherein the drive is controlled via a measuring device of a sensor system. The drive is arranged outside the tap transformer. The measuring device can be arranged outside the tap transformer or inside the tap transformer. In addition, the measuring device can be arranged in the on-load tap changer head. However, the measuring device and the drive are always at ground potential. The sensor unit is arranged in the tap transformer or in the on-load tap changer next to the vacuum switch tube. In the tap transformer or in the on-load tap changer means in the housing of the tap transformer or in or on the housing of the on-load tap changer. The sensor unit is particularly arranged in the oil reservoir of the load switching switch. The load switching switch is a part of the on-load tap changer and is also arranged in the interior of the tap transformer, that is, arranged in the housing of the tap transformer. The sensor unit and the vacuum switch tube are always at high voltage potential. This also applies to the load switching switch. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be described in detail below by means of exemplary embodiments with reference to the accompanying drawings.

[0026] In the figure:

[0027] Figure 1 A tap-changing transformer with an on-load tap-changer device is shown;

[0028] Figure 2 A sensor unit is shown. DETAILED DESCRIPTION

[0029] Figure 1A tap transformer 1 with an on-load tap changer device 30 is shown. The on-load tap changer device 30 has an on-load tap changer 2 and a sensor system 20. The on-load tap changer 2 is connected to a drive 3 and is actuated by the drive. The on-load tap changer 2 has a load changeover switch (not shown) and a selector. In addition, the load changeover switch has, and therefore the on-load tap changer 2 also has, at least one vacuum switching tube 4, which is used to switch under load. A sensor unit 10 is connected to the vacuum switching tube 4. The sensor unit is used to detect or determine the arc burning duration during actuation, in particular when the vacuum switching tube 4 is disconnected. The sensor unit 10 is preferably arranged in the on-load tap changer 4, in particular in the load changeover switch or arranged in the vicinity of the vacuum switching tube 4. In addition, the sensor unit 10 is connected to a measuring device 5. The sensor unit 10 and the measuring device 5 form a sensor system 20 for detecting or determining the arc burning duration.

[0030] Figure 2 A detailed view of a sensor unit 10 is shown. The sensor unit 10 is connected to the vacuum switching tube 4 of the on-load tap changer 2 at a first contact 4.1 and a second contact 4.2 of the vacuum switching tube 4. The sensor unit 10 has a voltage divider 11 which is arranged and designed to reduce a high voltage applied to the vacuum switching tube 10 to a lower voltage. In particular, the voltage divider 11 of the sensor unit is connected to the first contact 4.1 and the second contact 4.2 of the vacuum switching tube 4.

[0031] Furthermore, an energy generator 12 is provided. The energy generator provides the energy required for the operation of the sensor unit 10. The energy generator 12 can be designed, for example, as a current converter, a voltage converter or another converter that works according to the energy harvesting principle (by tapping temperature, mechanical vibrations, electric fields or magnetic fields). The energy generator 12 is either a fixed component of the sensor unit 10 (that is, integrated therein) or is electrically conductively connected to the sensor unit.

[0032] An energy conversion unit 13 is also provided. The energy conversion unit adapts the energy obtained by the energy generator 12 to the requirements and demands of the evaluation unit 14 and the transmitter 15 according to the specifications of the other components, namely the voltage and current. In addition, the energy conversion unit 13 generates a reference voltage. The energy conversion unit 13 can be designed, for example, as a rectifier network and can, for example, also include capacitors or coils for intermediate storage of energy.

[0033] An evaluation unit 14 (which is constructed as a comparator network, for example) is connected to the voltage divider 11 and the energy conversion unit 13. The evaluation unit 14 is constructed and arranged to evaluate the voltage detected or tapped from the voltage divider 11. Here, it is determined whether an arc exists in the vacuum switching tube 4 during switching by means of the voltage tapped from the voltage divider 11. Thus, for example, an arc exists in the vacuum switching tube when the tapped voltage is 15 mV to 25 mV. This voltage range is given here as an example. The tapped voltage range also depends on the characteristics of the individual components of the vacuum switching tube 4. The evaluation unit 14 is arranged and constructed to detect a specific voltage value or voltage range, process the specific voltage value or voltage range with a reference voltage or compare the specific voltage value or voltage range with a reference voltage and generate an output signal therefrom.

[0034] Furthermore, the evaluation unit 14 is connected to a transmitter 15. The transmitter transmits the output signal generated by the evaluation unit 14 to the measuring device 5. The transmitter 15 is preferably designed as a diode. The measuring device 5 at ground potential has a receiver 16, which is designed as a diode or a photodiode. In the example shown here, the transmitter 15 and the receiver 16 are connected to each other via an optical waveguide, which serves as a signal transmitter 17. Depending on the design of the transmitter 15, the receiver 16 and the signal transmitter 17, the signal transmission can be carried out in any desired manner, for example by radio, Bluetooth, WLAN, etc. The measuring device 5 can be arranged inside the tap transformer 1 under the on-load tap changer cover, or it can be arranged outside the tap transformer 1, for example in a motor drive or a voltage regulator.

[0035] The measuring device 5 further comprises a measuring device 18 by which the received output signal can be evaluated. The measuring device 18 is designed and provided for processing and evaluating the output signal and can have, for example, a corresponding processor and a memory.

[0036] When the on-load tap changer 2 is operated, the vacuum switch tube 4 of the on-load tap changer 2 is disconnected by means of the drive 3. Since a sinusoidal current generally flows through the on-load tap changer 2 and thus through the vacuum switch tube 4, an arc is generated between the contacts when the vacuum switch tube 4 is disconnected. These arcs are generally extinguished at the next current zero crossing or when the contacts of the vacuum switch tube are sufficiently far from each other. If the current is exactly at its zero point when disconnected, no arc is generated. The sensor unit 10 is used to detect the arc burning duration. Here, the voltage value or voltage range from the voltage divider 11 is converted into an output signal in the evaluation unit 14 and transmitted to the measuring device 5 via the transmitter 15. The measuring device 18 in the measuring device 5 measures the duration of the output signal and determines the arc burning duration from it. The duration of the output signal depends on the arc burning duration or is given by the arc burning duration. The measuring device 18 is constructed and arranged to determine the arc burning duration from the output signal of the sensor unit 10. Reference numerals list

[0037] 1 tap transformer

[0038] 2On-load tap changer

[0039] 3. Drive

[0040] 4 Vacuum switch tube

[0041] 4.1 First contact

[0042] 4.2 Second contact part

[0043] 5. Measuring device

[0044] 10 sensor units

[0045] 11 Voltage Divider

[0046] 12 Energy Generator

[0047] 13Energy conversion unit

[0048] 14 evaluation units

[0049] 15 Transmitter

[0050] 16 Receivers

[0051] 17Signal Transmitter

[0052] 18. Measuring device

[0053] 20 sensor system

[0054] 30 On-load tap-changer

Claims

1. A sensor system (20) for determining the duration of an arc burning in a vacuum interrupter (4), comprising: - a measuring device (5) comprising a receiver (16) and a measuring device (18); - a sensor unit (10) comprising a voltage divider (11), an energy generator (12), an energy conversion unit (13), an evaluation unit (14) and a transmitter (15); in, - the sensor unit (10) can be connected to a first contact portion (4.1) and a second contact portion (4.2) of the vacuum switching tube (4); The sensor unit (10) is connected to the measuring device (5) via a signal transmitter (17).

2. The sensor system (20) according to claim 1, wherein: - the transmitter (15) is designed as a diode; - the signal transmitter (17) is configured as an optical waveguide; The receiver (16) is designed as a photodiode.

3. The sensor system (20) according to any one of claims 1 to 2, wherein: The energy generator (12) is implemented as a current converter or a voltage converter or as a converter based on the energy harvesting principle.

4. The sensor system (20) according to any one of claims 1 to 3, wherein: The evaluation unit (14) is designed as a rectifier network.

5. The sensor system (20) according to any one of claims 1 to 4, wherein: The evaluation unit (14) is connected to the energy generator (12) via the energy conversion unit (13) in order to supply power to the sensor unit (10) and to generate a reference voltage.

6. The sensor system (20) according to any one of claims 1 to 5, wherein: The voltage divider (11) of the sensor unit (10) can be connected to a first contact (4.1) and a second contact (4.2) of the vacuum switching tube (4).

7. The sensor system (20) according to any one of claims 1 to 6, wherein: The voltage divider (11) taps off the voltage applied to the vacuum switching tube (4).

8. The sensor system (20) according to any one of claims 1 to 7, wherein: - the evaluation unit (14) generates an output signal based on its reference voltage from the energy conversion unit (13) and the voltage tapped by the voltage divider (11); The evaluation unit (14) transmits the output signal to the measuring device (5) by means of a transmitter (15).

9. An on-load tap changer device (30), comprising: - On-load tap changer (2) with vacuum switching tube (4); - a sensor system (20) having a measuring device (5) and a sensor unit (10) for determining the burning duration of an arc in a vacuum interrupter (4); in, - the sensor unit (10) is connected to a first contact portion (4.1) and a second contact portion (4.2) of the vacuum switching tube (4); - The measuring device (5) is connected to the sensor unit (10) via a signal transmitter (10). 10 . The on-load tap changer device ( 30 ) according to claim 7 , comprising a drive ( 3 ) for actuating the on-load tap changer ( 2 ), the drive ( 3 ) being controlled via a measuring device ( 5 ) of the sensor system ( 20 ).

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