A transient disturbance voltage measuring device

Abstract

The application discloses a kind of measuring devices of transient disturbance voltage, it is related to electric signal measurement field, including high voltage probe, three-channel adapter and digital oscilloscope;Wherein, three-channel adapter first output end is electrically connected with the first input channel of digital oscilloscope;First input channel is used to trigger the second input channel of digital oscilloscope to enter measurement state when input voltage is greater than threshold value, does not trigger the second input channel to enter measurement state when input voltage is not greater than threshold value;First input channel is used to measure tens of volts voltage;Second input channel is used for the measurement of disturbance electric signal, and second input channel is used to measure thousands of volts voltage.The application is according to the size of voltage input first input channel, based on the thought of not making background noise false triggering oscilloscope, to control whether second input channel enters measurement state, avoids the problem of oscilloscope false triggering caused by background noise being amplified.

Description

Technical Field

[0001] This invention relates to the field of electrical signal measurement, and in particular to a transient disturbance voltage measuring device. Background Technology

[0002] When conducting transient disturbance voltage tests in substations, oscilloscope channels typically require high-voltage probes with a turns ratio of 100:1 or 1000:1 at the measurement front end, and the oscilloscope internally needs to amplify the signal strength by 100 or 1000 times for signal strength compensation. However, in actual testing environments, especially in the complex environment of substations, the background noise bandwidth is usually very wide. Some background noise can couple directly from the cable or housing at the rear of the high-voltage probe into the oscilloscope. This background noise is amplified by the oscilloscope by 100 or 1000 times for signal strength compensation, resulting in a very large voltage amplitude, which can easily cause false triggering of the oscilloscope. Summary of the Invention

[0003] The purpose of this invention is to provide a transient disturbance voltage measurement device that can effectively trigger disturbance voltage.

[0004] To achieve the above objectives, the present invention provides the following solution:

[0005] A device for measuring transient disturbance voltage, the device comprising a high-voltage probe, a three-channel adapter, and a digital oscilloscope;

[0006] The high-voltage probe, with its high-voltage end used to measure interference signals;

[0007] The high-voltage probe has its low-voltage end electrically connected to the input end of the three-channel adapter.

[0008] The three-channel adapter has its first output terminal electrically connected to the first input channel of the digital oscilloscope. The first input channel is used to trigger the second input channel of the digital oscilloscope to enter the measurement state when the input voltage of the first input channel is greater than a threshold, and not to trigger the second input channel of the digital oscilloscope to enter the measurement state when the input voltage is not greater than the threshold. The first input channel is used to measure voltages of tens of volts.

[0009] The three-channel adapter has its second output terminal connected to the second input channel of the digital oscilloscope. The second input channel is used to measure the interference signal and to measure a voltage of several kilovolts.

[0010] Optionally, the first input channel is provided with a first compensation module, which is used to adjust the first compensation attenuation ratio to compensate the input voltage, so as to control the measurement state of the second input channel of the digital oscilloscope.

[0011] Optionally, the first input channel is used to adjust a first compensation attenuation ratio to make the input voltage greater than the trigger threshold based on the input voltage and the trigger threshold of the second input channel when the input voltage is greater than the threshold, so as to trigger the second input channel of the digital oscilloscope to enter the measurement state.

[0012] Optionally, the first input channel is used to adjust a first compensation attenuation ratio to make the input voltage less than the trigger threshold based on the input voltage and the trigger threshold of the second input channel when the input voltage is not greater than the threshold, so as not to trigger the second input channel of the digital oscilloscope to enter the measurement state.

[0013] Optionally, the second input channel is provided with a second compensation module, which is used to compensate the input voltage according to the second compensation attenuation ratio to restore the interference signal measured at the high voltage end of the high voltage probe.

[0014] Optionally, the second compensation attenuation ratio is matched with the transformation ratio of the high-voltage probe.

[0015] Optionally, the measurement range of the second input channel is set according to the historical values ​​of the substation disturbance signals.

[0016] Optionally, the high-voltage probe has a voltage amplitude of 40kV, a bandwidth of DC-220MHz, and an input impedance of 900Ω. The Pintech 6039A high-voltage probe has an attenuation ratio of 1000:1.

[0017] Optionally, the digital oscilloscope is a RIGOL MSO5074 digital oscilloscope with a sampling rate of 8GS / s, a measurement bandwidth of 70MHz, and a maximum storage depth of 200Mpts.

[0018] Optionally, the sampling rate of the first input channel is 1 GS / s, the sampling rate of the second input channel is 200 MS / s, and the sampling time of the digital oscilloscope is 1 ms.

[0019] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0020] This invention provides a device for measuring transient disturbance voltage. The device includes a high-voltage probe, a three-channel adapter, and a digital oscilloscope. The high-voltage probe has a high-voltage end for measuring the disturbance signal. The low-voltage end of the high-voltage probe is electrically connected to the input end of the three-channel adapter. The first output end of the three-channel adapter is electrically connected to the first input channel of the digital oscilloscope. The first input channel is used to trigger the second input channel of the digital oscilloscope to enter the measurement state when the input voltage of the first input channel is greater than a threshold, and not to trigger the second input channel of the digital oscilloscope to enter the measurement state when the input voltage is not greater than the threshold. The first input channel is used to measure an input voltage of tens of volts. The second output end of the three-channel adapter is electrically connected to the second input channel of the digital oscilloscope. The second input channel is used to measure the disturbance signal and is used to measure an input voltage of several kilovolts. This invention controls whether the second input channel enters the measurement state based on the voltage magnitude of the first input channel, avoiding the problem of oscilloscope false triggering caused by amplified background noise. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of a transient disturbance voltage measuring device provided in an embodiment of the present invention;

[0023] Figure 2 This is a test result diagram of the first input channel provided in an embodiment of the present invention;

[0024] Figure 3 This is a test result diagram of the second input channel for a 2kV disturbance voltage provided in an embodiment of the present invention;

[0025] Figure 4 The diagram shows the test results of the second input channel for the 4kV disturbance voltage provided in this embodiment of the invention. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] The purpose of this invention is to provide a transient disturbance voltage measurement device that accurately triggers disturbance voltage.

[0028] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] This invention provides a device for measuring transient disturbance voltage, such as... Figure 1 As shown, the measuring device includes a high-voltage probe, a three-channel adapter, and a digital oscilloscope.

[0030] The high-voltage probe is used to measure interference signals at its high-voltage end.

[0031] The high-voltage probe has its low-voltage end electrically connected to the input end of the three-channel adapter.

[0032] The three-channel adapter has its first output terminal electrically connected to the first input channel of the digital oscilloscope. The first input channel is used to trigger the second input channel of the digital oscilloscope to enter the measurement state when the input voltage of the first input channel is greater than a threshold, and not to trigger the second input channel of the digital oscilloscope to enter the measurement state when the input voltage is not greater than the threshold. The first input channel is used to measure voltages of tens of volts.

[0033] The three-channel adapter has its second output terminal connected to the second input channel of the digital oscilloscope. The second input channel is used to measure the interference signal and to measure a voltage of several kilovolts.

[0034] When measuring interference signals, the high-voltage end of the high-voltage probe is inserted into the interference signal port or the interference signal cable.

[0035] Specifically, the low-voltage end of the high-voltage probe is connected to the input end of the three-channel adapter via a coaxial cable, the first output end of the three-channel adapter is connected to the first input channel of the oscilloscope via a coaxial cable, and the second output end of the three-channel adapter is connected to the second input channel of the oscilloscope via a coaxial cable.

[0036] Specifically, the transformation ratio of the high-voltage probe is 100:1 or 1000:1.

[0037] In the process of measuring transient interference signals, due to the complex environment of the substation, there is a lot of background noise. This background noise can be directly coupled from the cable or shell at the back end of the high voltage probe into the oscilloscope. The voltage amplitude of the background noise is generally within 1 volt, and as the interference signal increases, the voltage amplitude of the background noise approaches 1 volt.

[0038] According to the electromagnetic compatibility immunity assessment standard at the most severe level in GB / T 20840.7-2007 Instrument Transformers Part 7: Electronic Voltage Transformers, the most severe level of interference signal is level 4 with a voltage of 4kV.

[0039] In some embodiments, a first compensation module is provided in the first input channel. The first compensation module is used to adjust a first compensation attenuation ratio to compensate the input voltage, thereby controlling the measurement state of the second input channel of the digital oscilloscope. Specifically, there are two adjustment scenarios:

[0040] (1) When the input voltage is greater than the threshold, the first compensation attenuation ratio is adjusted according to the input voltage and the trigger threshold of the second input channel to make the input voltage greater than the trigger threshold, so as to trigger the second input channel of the digital oscilloscope to enter the measurement state. For example: Setting the threshold to 1V (this value can be set according to requirements), and the trigger threshold to 10V, when the high-voltage probe measures a 1kV signal, the signal is attenuated by a high factor (1000:1) by the high-voltage probe, resulting in a 1V voltage signal. When this voltage signal is transmitted to the first input channel, due to background noise (e.g., 0.8V), the input voltage of the first input channel is approximately 1.8V. Since this input voltage is greater than the 1V threshold, the second channel should be triggered to measure the interference signal. Therefore, by adjusting the first compensation attenuation ratio of the first compensation module to reach or exceed the trigger threshold of 10V, the second channel is triggered to perform the measurement. Specifically, the first compensation attenuation ratio can be adjusted to 1:10. In this case, the compensated 1.8V reaches an intensity of 18V, which is higher than the trigger threshold of 10V, thus triggering the second input channel of the digital oscilloscope to enter the measurement state. Of course, the first compensation attenuation ratio can also be adjusted to 1:20, 1:30, etc.

[0041] (2) When the input voltage is not greater than the threshold, adjust the first compensation attenuation ratio according to the input voltage and the trigger threshold of the second input channel so that the input voltage is less than the trigger threshold, so as not to trigger the second input channel of the digital oscilloscope to enter the measurement state. For example: set the above threshold to 1V (this value can be set according to the requirements), and the trigger threshold to 10V. When there is no interference voltage, the signal voltage measured by the high voltage probe is 0. When the voltage signal is transmitted to the first input channel, due to the influence of background noise, for example, the background noise is 0.8V, the input voltage of the first input channel is about 0.8V. At this time, the input voltage is less than the threshold of 1V. According to the requirements, the second channel should not be triggered to measure the interference signal. Therefore, the first compensation attenuation ratio of the first compensation module should be adjusted to be less than the trigger threshold of 10V, so as not to trigger the second channel to measure. Specifically, the first compensation attenuation ratio can be adjusted to 1:1. At this time, 0.8V is lower than the trigger threshold of 10V, so as not to trigger the second input channel of the digital oscilloscope to enter the measurement state.

[0042] In some embodiments, a second compensation module is provided in the second input channel. The second compensation module is used to compensate the input voltage according to the second compensation attenuation ratio to restore the interference signal measured at the high voltage end of the high voltage probe.

[0043] The second compensation attenuation ratio is matched with the transformation ratio of the high-voltage probe. For example, when the high-voltage probe in the measuring device is a Pintech 6039A high-voltage probe with an attenuation ratio of 1000:1, an interference signal of approximately 2kV is reduced to a 2V voltage signal after being attenuated by a high factor by the high-voltage probe. In order to intuitively observe the magnitude of the interference signal, a second compensation module with an amplification factor of 1000 is provided in the second input channel for signal strength compensation and restoration.

[0044] In some embodiments, since background noise is coupled into the oscilloscope through the cable or housing at the rear end of the high-voltage probe, the voltage peak of the test result includes the voltage of both the interference signal and the background noise when performing interference signal testing. The measurement device proposed in this invention separates triggering from measurement, enabling accurate calculation of the measurement result of the interference signal. The specific measurement method is as follows:

[0045] After conducting transient disturbance signal tests, compare the data from the first input channel and the second input channel. If the first input channel is triggered and all waveforms from the second input channel remain within their ranges, the test is considered valid.

[0046] Specifically, such as Figure 2The moment when the waveform exceeds the range in the first input channel waveform is recorded as t0. The interference signal waveform before t0 is based on the first input channel (multiplied by the compensation factor corresponding to the high-voltage probe transformation ratio). For example, when the first compensation attenuation ratio of the first input channel is 1:1, the voltage value corresponding to the interference signal waveform of the first input channel before t0 is 0.2V, and the voltage amplitude of the background noise is 0.2V. Therefore, the signal input to the second input channel contains a noise signal of 0.2V. When the second input channel is equipped with a second compensation module with an amplification factor of 1000, the 0.2V noise signal is amplified to 200V. Therefore, subtracting the 200V noise signal from the peak voltage of the test result yields the accurate interference signal.

[0047] In some embodiments, the measurement range of the second input channel is set according to historical values ​​of substation disturbance signals.

[0048] Specifically, the range of the digital oscilloscope is set according to the electromagnetic compatibility immunity assessment standard at the most severe level (level 4, 4kV) in GB / T 20840.7-2007 Instrument Transformers Part 7: Electronic Voltage Transformers. At the same time, in order to leave an appropriate test margin, the range of the oscilloscope is set to 5kV.

[0049] In some embodiments, when measuring interference signals, the high-voltage probe in the measuring device uses a voltage amplitude of 40kV, a bandwidth of DC-220MHz, and an input impedance of 900Ω. The device features a Pintech 6039A high-voltage probe with an attenuation ratio of 1000:1; a RIGOL MSO5074 digital oscilloscope with a sampling rate of 8GS / s, a measurement bandwidth of 70MHz, a maximum storage depth of 200Mpts, and four analog signal channels that can operate simultaneously; a sampling rate of 1GS / s for the first input channel, a sampling rate of 200MS / s for the second input channel, a sampling time of 1ms for the digital oscilloscope, and a three-channel BNC adapter.

[0050] In summary, this invention has the following advantages: A three-way BNC connector is used on the connection channel between the output end of the high-voltage probe and the oscilloscope. The output signal of the high-voltage probe is split into two by the three-channel BNC adapter, and input to two different analog signal channels of the digital oscilloscope. By appropriately configuring the two channels of the digital oscilloscope, channel one (the first input channel) is used for effective triggering of the oscilloscope, while its internal channel two (the second input channel) is used for signal measurement. This configuration method improves the effectiveness of transient disturbance testing. By comparing the two pass / fail test results, a balance between effective triggering and range measurement of the oscilloscope is achieved.

Claims

1. A device for measuring transient disturbance voltage, characterized in that, The measuring device includes a high-voltage probe, a three-channel adapter, and a digital oscilloscope; The high-voltage probe has a high-voltage end used to measure interference signals, and a low-voltage end connected to the input signal of the three-channel adapter. The first output terminal of the three-channel adapter is connected to the first input channel of the digital oscilloscope for electrical signal transmission. The first input channel is used to trigger the second input channel of the digital oscilloscope to enter the measurement state when the input voltage of the first input channel is greater than a first threshold, and not to trigger the second input channel of the digital oscilloscope to enter the measurement state when the input voltage is not greater than the first threshold; the first input channel is used to measure a voltage of tens of volts; The three-channel adapter has its second output terminal connected to the second input channel of the digital oscilloscope; the second input channel is used to measure the interference signal and to measure a voltage of several kilovolts. The voltage amplitude of the background noise is within 1 volt, and the first threshold for triggering the second input channel from the first input channel is set to 1V.

2. The measuring device according to claim 1, characterized in that, The first input channel is provided with a first compensation module, which is used to adjust the first compensation attenuation ratio to compensate the input voltage, so as to control whether the second input channel of the digital oscilloscope enters the measurement state.

3. The measuring device according to claim 2, characterized in that, The first input channel is used to adjust the first compensation attenuation ratio according to the input voltage and the second trigger threshold of the second input channel when the input voltage is greater than the first threshold, so as to trigger the second input channel of the digital oscilloscope to enter the measurement state.

4. The measuring device according to claim 2, characterized in that, The first input channel is used to adjust the first compensation attenuation ratio so that the input voltage is less than the second trigger threshold according to the input voltage and the second trigger threshold of the second input channel when the input voltage is not greater than the first threshold, so as not to trigger the second input channel of the digital oscilloscope to enter the measurement state.

5. The measuring device according to claim 1, characterized in that, The second input channel is equipped with a second compensation module, which is used to compensate the input voltage according to the second compensation attenuation ratio to restore the interference signal measured at the high voltage end of the high voltage probe.

6. The measuring device according to claim 5, characterized in that, The second compensation attenuation ratio is matched with the transformation ratio of the high-voltage probe.

7. The measuring device according to claim 1, characterized in that, The measurement range of the second input channel is set according to the historical values ​​of the substation's disturbance signals.

8. The measuring device according to claim 1, characterized in that, The high-voltage probe has a voltage amplitude of 40kV, a bandwidth of DC-220MHz, and an input impedance of 900Ω. The Pintech 6039A high-voltage probe has an attenuation ratio of 1000:

1.

9. The measuring device according to claim 1, characterized in that, The digital oscilloscope used is a RIGOL MSO5074 digital oscilloscope with a sampling rate of 8GS / s, a measurement bandwidth of 70MHz, and a maximum storage depth of 200Mpts.

10. The measuring device according to claim 1, characterized in that, The sampling rate of the first input channel is 1 GS / s, the sampling rate of the second input channel is 200 MS / s, and the sampling time of the digital oscilloscope is 1 ms.

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