Sensor system for determining the arc burning duration, and load stage switching apparatus

Abstract

The invention relates to a sensor system (20) for determining the arc burning duration in a vacuum interruptor (4), comprising - a measurement apparatus (5) having a receiver (16) and a measurement 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 an emitter (15); wherein - the sensor unit (10) can be connected to a first contact (4.1) and a second contact (4.2) of a vacuum interruptor (4); - the sensor unit (10) is connected via a signal transmitter (17) to the measurement apparatus (5).

Description

[0001] Sensor system for determining the arc burning time and on-load tap-changer device

[0002] The invention relates to a sensor system for determining the arc burning duration and on-load tap changer device.

[0003] On-load tap-changers are used for uninterrupted switching between different winding taps of an electrical device, such as a power transformer or a variable-voltage reactor. Due to the fact that the switching elements, such as vacuum interrupters and selector arms, are always at high-voltage potential, monitoring of these components is generally not required. However, means and methods for monitoring these components are desirable.

[0004] It is therefore an object of the present invention to provide a sensor system which enables accurate and cost-effective monitoring of vacuum interrupters.

[0005] This object is achieved by the respective subject matter of the independent claims. Further embodiments are the subject matter of the dependent claims.

[0006] The invention proposes a sensor system for determining the arc burning duration in a vacuum interrupter, comprising a measuring device with a receiver and a measuring unit; a sensor unit with a voltage divider, an energy generator, an energy conversion unit, an evaluation unit, and a transmitter; wherein the sensor unit is connectable to a first contact and a second contact of a vacuum interrupter; the sensor unit is connected to the measuring device via a signal transmitter.

[0007] By connecting the sensor unit directly to a vacuum interrupter, it is possible to determine the arc burning duration. The sensor unit's voltage divider detects the voltage applied to the vacuum interrupter when an arc occurs in the vacuum interrupter, or taps the voltage applied to the vacuum interrupter. A detected arc is transmitted as an output signal to the measuring device via the evaluation unit and the transmitter, and the signal is evaluated by the measuring device. Depending on the duration of the output signal, the duration of the arc burning duration can be determined. The sensor unit is independently powered by the energy generator. This is particularly advantageous because the sensor unit is at the high-voltage potential. Complex cabling for a power supply is not necessary.

[0008] The transmitter and receiver can be configured in any way; for example, the transmitter can be a diode and the receiver a photodiode. In such an embodiment, the signal transmitter is then configured as an optical fiber. Furthermore, depending on the configuration of the transmitter, receiver, and signal transmitter, the signal transmission can be carried out in any way, for example, via radio, Bluetooth, Wi-Fi, etc.

[0009] The energy generator can, for example, be a current transformer, a voltage transformer, or a converter based on the energy harvesting principle. This is preferably located within the tap-change transformer, preferably at the high-voltage potential.

[0010] The evaluation unit can also be designed as a rectifier network. The evaluation unit is preferably connected to the energy generator via the energy conversion unit to supply the sensor unit with energy. The voltage divider of the sensor unit is connected to the first contact and the second contact of the vacuum interrupter to detect the arc burning duration.

[0011] The sensor unit is designed and configured to be connected to a vacuum interrupter of an on-load tap-changer, in particular the sensor unit is designed and configured to be connected to a first and a second contact of the vacuum interrupter.

[0012] The vacuum interrupter can be designed in any desired manner and can have a first contact and a second contact. The contacts extend from the interior of the vacuum interrupter to the outside. The sensor unit can be connected directly to the contacts of the vacuum interrupter or to conductive elements such as cables connected to the contacts.

[0013] The invention further proposes an on-load tap-changer device, comprising an on-load tap-changer with a vacuum interrupter; a sensor system with a measuring device and a sensor unit for determining the arc burning duration in the vacuum interrupter; wherein the sensor unit is connected to a first contact and to a second contact of the vacuum interrupter; and the measuring device is connected to the sensor unit via a signal transmitter. The on-load tap-changer device makes it possible to determine the arc burning duration within a vacuum interrupter of the on-load tap-changer. This ensures that arcs within the on-load tap-changer are extinguished during actuation. Furthermore, based on this information, the on-load tap-changer actuation can be adjusted via the drive so that the arc burning duration is as short as possible.By locating the sensor unit in close proximity to the vacuum interrupter, the on-load tap-changer device is particularly compact. Furthermore, the sensor unit is powered independently by its own power generator.

[0014] The on-load tap-changer device further comprises a drive for actuating the on-load tap-changer, wherein the drive is controlled via the measuring device of the sensor system. The drive is arranged externally on the tap-changer. The measuring device can be arranged externally on the tap-changer or inside the tap-changer. Furthermore, the measuring device can be arranged in the on-load tap-changer head. However, the measuring device and the drive are always connected to earth potential. The sensor unit is arranged inside the tap-changer or inside the on-load tap-changer in the immediate vicinity of the vacuum interrupter. Inside the tap-changer or inside the on-load tap-changer means in the housing of the tap-changer or in or on the housing of the on-load tap-changer. In particular, the sensor unit is arranged in the oil compartment of the diverter switch.The diverter switch is part of the on-load tap-changer and is also located inside a tap-changer, i.e., in its housing. The sensor unit and the vacuum interrupter are always connected to the high-voltage potential. This also applies to the diverter switch.

[0015] In the following, the invention is explained in detail using exemplary embodiments with reference to the drawings.

[0016] It shows

[0017] Figure 1 shows a tap-changer with an on-load tap-changer device;

[0018] Figure 2 shows a sensor unit. Figure 1 shows a tap-changer 1 with an on-load tap-changer device 30. 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 latter. The on-load tap-changer 2 has a diverter switch and a selector (not shown). Furthermore, the diverter switch and thus also the on-load tap-changer 2 has at least one vacuum interrupter 4, which is used for switching under load. A sensor unit 10 is connected to the vacuum interrupter 4. The sensor unit is used to detect or determine the arc burning duration during actuation, in particular when opening the vacuum interrupter 4. The sensor unit 10 is preferably arranged in the on-load tap-changer 4, in particular in the diverter switch or in the immediate vicinity of the vacuum interrupter 4.Furthermore, 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.

[0019] Figure 2 shows a detailed view of the sensor unit 10. The sensor unit 10 is connected to the vacuum interrupter 4 of the on-load tap-changer 2 via a first contact 4.1 and a second contact 4.2 of the vacuum interrupter 4. The sensor unit 10 has a voltage divider 11, which is designed and configured to reduce the high voltage across the vacuum interrupter 10 to a lower voltage. In particular, the voltage divider 11 of the sensor unit is connected to the first contact 4.1 and to the second contact 4.2 of the vacuum interrupter 4.

[0020] Furthermore, an energy generator 12 is provided. This provides the energy required to operate the sensor unit 10. The energy generator 12 can be designed, for example, as a current transformer, a voltage transformer, or another transformer that functions according to the energy harvesting principle (by tapping temperature, mechanical vibrations, electrical or magnetic fields). The energy generator 12 is either an integral part of the sensor unit 10, i.e., integrated, or is electrically connected to it.

[0021] Furthermore, an energy conversion unit 13 is provided. This adapts the energy received from the energy generator 12 to the needs and requirements of the evaluation unit 14 and the transmitter 15 in accordance with the specifications of the other components, i.e. voltage and current. The energy conversion unit 13 also generates a reference voltage. The energy conversion unit 13 can be designed, for example, as a rectifier network and can also comprise, for example, capacitors or coils for intermediate energy storage. The evaluation unit 14, which is designed, for example, as a comparator network, is connected to the voltage divider 11 and the energy conversion unit 13. The evaluation unit 14 is designed and configured to evaluate the voltage detected or tapped by the voltage divider 11. Here, based on the voltage tapped by the voltage divider 11, it is determined whether an arc is present in the vacuum interrupter 4 during a switching operation.For example, if the voltage tapped is between 15 mV and 25 mV, an arc is present in the vacuum interrupter. This voltage range is given here as an example. The tapped voltage range depends, among other things, on the properties of the individual components of the vacuum interrupter 4. The evaluation unit 14 is configured and designed to detect a specific voltage value or a voltage range, process or compare it with a reference voltage, and generate an output signal therefrom.

[0022] Furthermore, the evaluation unit 14 is connected to a transmitter 15. This transmits the output signals generated by the evaluation unit 14 to the measuring device 5. The transmitter 15 is preferably designed as a diode. The measuring device 5, which is at ground potential, has a receiver 16 which is designed as a diode or photodiode. In the example shown here, the transmitter 15 and the receiver 16 are connected to one another via an optical fiber, which serves as a signal transmitter 17. Depending on the design of the transmitter 15, receiver 16 and signal transmitter 17, the signals can be transmitted in any desired manner, for example via radio, Bluetooth, WLAN, etc. The measuring device 5 can be arranged inside the tap-changer 1 below the on-load tap-changer cover or externally on the tap-changer 1, for example in the motor drive or voltage regulator.

[0023] The measuring device 5 also has a measuring device 18 with which the received output signal can be evaluated. The measuring device 18 is designed and configured to process and evaluate the output signal and can, for example, have a corresponding processor and a memory.

[0024] When the on-load tap-changer 2 is operated, a vacuum interrupter 4 of the on-load tap-changer 2 is opened by means of the drive 3. Since a sinusoidal current generally flows through the on-load tap-changer 2 and thus through the vacuum interrupter 4, arcs can occur between the contacts when the vacuum interrupter 4 opens. These arcs generally extinguish when the current next passes zero or when the contacts of the vacuum interrupter are far enough apart. If the current is at zero when the switch is opened, no arc will occur. The sensor unit 10 is used to record the arc duration. A voltage value or a 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 control device 5 measures the duration of the output signal and determines the arc duration from this.The duration of the output signal depends on or is predetermined by the arc burning time. The measuring device 18 is designed and configured to determine the arc burning time from the output signal of the sensor unit 10.

[0025] Reference symbol

[0026] 1 step transformer

[0027] 2 on-load tap-changers

[0028] 3 Drive

[0029] 4 vacuum interrupters

[0030] 4.1 First contact

[0031] 4.2 second contact

[0032] 5 Measuring device

[0033] 10 Sensor unit

[0034] 11 voltage divider

[0035] 12 energy producers

[0036] 13 Energy conversion unit

[0037] 14 Evaluation unit

[0038] 15 channels

[0039] 16 recipients

[0040] 17 signal transmitters

[0041] 18 Measuring device

[0042] 20 Sensor system

[0043] 30 On-load tap-changer device

Claims

Claims 1. Sensor system (20) for determining the arc burning duration in a vacuum interrupter (4), comprising a measuring device (5) with a receiver (16) and a measuring unit (18); a sensor unit (10) with 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) is connectable to a first contact (4.1) and a second contact (4.2) of a vacuum interrupter (4); the sensor unit (10) is connected to the measuring device (5) via a signal transmitter (17).

2. Sensor system (20) according to claim 1, wherein the transmitter (15) is designed as a diode; the signal transmitter (17) is designed as an optical fiber; the receiver (16) is designed as a photodiode.

3. Sensor system (20) according to one of claims 1 to 2, wherein the energy generator (12) is a current converter or voltage converter or a converter according to the energy harvesting principle.

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

5. Sensor system (20) according to 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 the sensor unit (10) with energy and to generate a reference voltage.

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

7. Sensor system (20) according to one of claims 1 to 6, wherein the voltage divider (11) taps a voltage applied to the vacuum interrupter (4).

8. Sensor system (20) according to one of claims 1 to 7, wherein the evaluation unit (14) generates an output signal based on the reference voltage from the energy conversion unit (13) and the voltage tapped from the voltage divider (11); the evaluation unit (14) transmits the output signal to the measuring device (5) via the transmitter (15).

9. On-load tap-changer device (30), comprising an on-load tap-changer (2) with a vacuum interrupter (4); a sensor system (20) with a measuring device (5) and a sensor unit (10) for determining the arc burning duration in the vacuum interrupter (4); wherein the sensor unit (10) is connected to a first contact (4.1) and to a second contact (4.2) of the vacuum interrupter (4); the measuring device (5) is connected to the sensor unit (10) via a signal transmitter (10).

10. On-load tap-changer device (30) according to claim 7, comprising a drive (3) for actuating the on-load tap-changer (2), wherein the drive (3) is controlled via the measuring device (5) of the sensor system (20).

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