Filter for partial discharge monitoring and partial discharge monitoring system

Abstract

The invention relates to a filter for partial discharge monitoring and a partial discharge monitoring system, and belongs to the technical field of power equipment detection. The filter comprises an input terminal, a sensor identification unit used for identifying the type of the partial discharge sensor, a filtering channel switching circuit and more than two filtering channels located in different working frequency bands, and the input terminal of the filter is used for being connected with the output end of the partial discharge sensor. The filtering channel switching circuit comprises an input end and output ends connected with all filtering channels, the input end of the filtering channel switching circuit and an I / O port of the sensor identification unit are both connected with an input terminal of the filter, and the filtering channel switching circuit is in communication connection with the sensor identification unit. And the filtering channel switching circuit is used for only conducting a filtering channel matched with the partial discharge sensor according to the type of the partial discharge sensor transmitted by the sensor identification unit. According to the invention, the generalization of the partial discharge monitoring filtering function is realized, the filter does not need to be manually designed, and the configuration efficiency is high.

Description

Technical Field

[0001] The invention belongs to the technical field of power equipment detection, and in particular relates to a filter for partial discharge monitoring and a partial discharge monitoring system. Background Art

[0002] Partial discharge is an important parameter to ensure the insulation performance of high-voltage electrical equipment, and it is also a precursor to insulation failure. Therefore, high-voltage electrical equipment (such as GIS) is usually monitored for partial discharge to determine whether insulation failure occurs. Common partial discharge monitoring methods include high-frequency current method, ultra-high frequency method, ultrasonic method, transient ground wave method, etc. Each monitoring method is implemented using a corresponding partial discharge sensor. The detection of partial discharge is usually affected by various interferences, but the spectrum characteristics and interference noise of partial discharge signals are different. Commonly used partial discharge monitoring methods each have their own working frequency bands that their partial discharge sensors respond to, such as the monitoring frequency band of ultrasonic partial discharge sensors is 20K~200KHz, the monitoring frequency band of ultra-high frequency partial discharge sensors is 300M~1500MHz, and the monitoring frequency band of transient ground wave partial discharge sensors is 3M~100MHz. Therefore, when filtering the partial discharge signals collected by different types of partial discharge sensors, it is necessary to configure filters that are compatible with their working frequency bands.

[0003] At present, when configuring filters for partial discharge monitoring systems, the filter is usually manually set according to the type of partial discharge sensor configured. This configuration method has the following problems: 1) low efficiency; 2) once the filter is fixed, if the site conditions change and the configured filter is not suitable for the site conditions, it is inconvenient to change the filter. Summary of the invention

[0004] The object of the present invention is to provide a filter for partial discharge monitoring and a partial discharge monitoring system, so as to solve the problems of low configuration efficiency and poor filter versatility when configuring the filter in the partial discharge monitoring system.

[0005] The filter for partial discharge monitoring provided by the present invention to solve the above technical problems includes an input terminal, a sensor identification unit for identifying the type of partial discharge sensor, a filter channel switching circuit and more than two filter channels in different working frequency bands, the input terminal of the filter is used to connect the output end of the partial discharge sensor, the filter channel switching circuit includes an input end and an output end connected to each filter channel, the input end of the filter channel switching circuit and the I / O port of the sensor identification unit are both connected to the input terminal of the filter, the filter channel switching circuit is communicatively connected to the sensor identification unit, and the filter channel switching circuit is used to only conduct the filter channel adapted to the partial discharge sensor according to the type of the partial discharge sensor transmitted by the sensor identification unit.

[0006] Furthermore, the sensor identification unit includes a processor and a pulse signal generator and a signal receiving circuit connected to the processor, the pulse signal generator is used to send a pulse signal of a fixed amplitude to the partial discharge sensor, the signal receiving circuit is used to receive a reflected signal reflected from the partial discharge sensor, and the processor is used to calculate the characteristic impedance of the partial discharge sensor based on the sent pulse signal and the reflected signal, and determine the type of the partial discharge sensor based on the characteristic impedance of the partial discharge sensor.

[0007] Furthermore, the filter channel switching circuit includes a controller and a switch switching unit. The controller controls the switch switching unit. The controller communicates with the sensor identification unit. The controller is used to control the switch switching unit according to the type of partial discharge sensor transmitted by the sensor identification unit to achieve that only the filter channel compatible with the partial discharge sensor is turned on.

[0008] Furthermore, the filter channel switching circuit is also used to cyclically turn on each filter channel in a time period after the partial discharge monitoring system starts to work and before the filter channel matching is completed.

[0009] Furthermore, the switch switching unit is a radio frequency switch.

[0010] The beneficial effect of the present invention is that the filter of the present invention automatically selects a filter frequency band suitable for real-time working conditions according to the type of partial discharge sensor, so it can be used in various types of partial discharge monitoring systems, realizing the universalization of partial discharge monitoring filter functions. In addition, it is no longer necessary to manually design the filter, and the configuration efficiency is high.

[0011] The partial discharge monitoring system provided by the present invention to solve the above technical problems includes a partial discharge sensor, and the system also includes a filter, wherein the filter includes an input terminal, a sensor identification unit for identifying the type of the partial discharge sensor, a filter channel switching circuit and more than two filter channels in different working frequency bands, the input terminal of the filter is connected to the output end of the partial discharge sensor, the filter channel switching circuit includes an input end and an output end connected to each filter channel, the input end of the filter channel switching circuit and the I / O port of the sensor identification unit are both connected to the input terminal of the filter, the filter channel switching circuit is communicatively connected to the sensor identification unit, and the filter channel switching circuit is used to only conduct the filter channel adapted to the partial discharge sensor according to the type of the partial discharge sensor transmitted by the sensor identification unit.

[0012] Furthermore, the sensor identification unit includes a processor and a pulse signal generator and a signal receiving circuit connected to the processor, the pulse signal generator is used to send a pulse signal of a fixed amplitude to the partial discharge sensor, the signal receiving circuit is used to receive a reflected signal reflected from the partial discharge sensor, and the processor is used to calculate the characteristic impedance of the partial discharge sensor based on the sent pulse signal and the reflected signal, and determine the type of the partial discharge sensor based on the characteristic impedance of the partial discharge sensor.

[0013] Furthermore, the filter channel switching circuit includes a controller and a switch switching unit. The controller controls the switch switching unit. The controller communicates with the sensor identification unit. The controller is used to control the switch switching unit according to the type of partial discharge sensor transmitted by the sensor identification unit to achieve that only the filter channel compatible with the partial discharge sensor is turned on.

[0014] Furthermore, the filter channel switching circuit is also used to cyclically turn on each filter channel in a time period after the partial discharge monitoring system starts to work and before the filter channel matching is completed.

[0015] Furthermore, the switch switching unit is a radio frequency switch.

[0016] The beneficial effect of the present invention is that the filter of the present invention automatically selects a filter frequency band suitable for real-time working conditions according to the type of partial discharge sensor, so it can be used in various types of partial discharge monitoring systems, realizing the universalization of partial discharge monitoring filter functions. In addition, it is no longer necessary to manually design the filter, and the configuration efficiency is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure of a filter for partial discharge monitoring according to an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings.

[0019] The basic idea of ​​the present invention is to enable the filter to adapt to the on-site working conditions, automatically select the filtering frequency band suitable for the real-time working conditions, and realize the universalization of the partial discharge monitoring filtering function.

[0020] Filter embodiment of the present invention for partial discharge monitoring Based on the above basic ideas, Figure 1As shown, the filter for partial discharge monitoring of the present invention includes an input terminal, an output terminal, a sensor identification unit for identifying the type of partial discharge sensor, a filter channel switching circuit and more than two filter channels in different working frequency bands, the input terminal of the filter is used to connect the output end of the partial discharge sensor, the filter channel switching circuit includes an input end and an output end, the input end of the filter channel switching circuit and the I / O port of the sensor identification unit are both connected to the input terminal of the filter, the output end of the filter channel switching circuit is connected to the input end of each filter channel, the output end of each filter channel is connected to the output terminal of the filter, the filter channel switching circuit is communicatively connected to the sensor identification unit, and the filter channel switching circuit is used to only conduct the filter channel adapted to the partial discharge sensor according to the type of partial discharge sensor transmitted by the sensor identification unit.

[0021] Preferably, if Figure 1 As shown, the sensor identification unit includes a processor and a pulse signal generator and a signal receiving circuit connected to the processor. The pulse signal generator is used to send a pulse signal with a fixed amplitude to the partial discharge sensor. The signal receiving circuit is used to receive a reflected signal reflected from the partial discharge sensor and send it to the processor. The processor analyzes the received reflected signal and calculates the characteristic impedance of the partial discharge sensor in combination with the sent pulse signal, and determines the type of the partial discharge sensor according to the characteristic impedance of the partial discharge sensor.

[0022] When a pulse signal is transmitted to the partial discharge sensor, the pulse signal propagates on the transmission line and is reflected at a place where the impedance mismatch occurs (such as the end or connection point of the sensor). The amplitude and phase of the reflected signal depend on the characteristic impedance of the transmission line and the impedance of the reflection point. By measuring the amplitude and phase of the incident signal and the reflected signal, the reflection coefficient λ can be calculated, which represents the proportional relationship between the reflected signal and the incident signal. The reflection coefficient λ, the impedance of the reflection point, and the characteristic impedance of the transmission line have a specific relationship, and the characteristic impedance of the transmission line is known, so by measuring the reflection coefficient λ, the characteristic impedance of the partial discharge sensor can be calculated.

[0023] Preferably, the filter channel switching circuit includes a controller and a switch switching unit. The controller controls the switch switching unit. The controller communicates with the sensor identification unit. The controller is used to control the switch switching unit according to the type of partial discharge sensor transmitted by the sensor identification unit, thereby turning on the filter channel adapted to the partial discharge sensor and disconnecting the remaining other filter channels.

[0024] Preferably, after the partial discharge monitoring system starts working, but during the period before the filter channel matching is completed, the filter channel switching circuit cyclically turns on each filter channel, that is, only one filter channel is connected per unit time. After the sensor identification unit determines the frequency band of the interference signal under the working condition, the filter channel switching circuit automatically turns on the filter channel corresponding to the interference frequency band and disconnects other filter channels, thereby filtering the partial discharge signal collected by the partial discharge sensor with the filter channel corresponding to the interference frequency band.

[0025] Preferably, the switch switching unit in the filter channel switching circuit of this embodiment is a radio frequency switch, and the radio frequency switch structure is a prior art and is not described in detail here. The input pin of the radio frequency switch chip is connected to the filter input port through a cable, and each output pin of the chip is respectively connected to the input end of each filter channel, and the controller is connected to the control pin of the radio frequency switch. Of course, as other implementations, the switch switching unit can also be a single-pole multi-throw switch, the moving contact of the single-pole multi-throw switch is connected to the input terminal of the filter, and each static contact is respectively connected to each filter channel. When a certain filter channel needs to be turned on, it is only necessary to control the moving contact to contact the static contact connected to the filter channel. For example, when the filter has four filter channels, a single-pole four-throw switch can be used to achieve this.

[0026] Preferably, the filter channel of this embodiment is composed of an LTCC chip with a corresponding frequency band and impedance matching wiring on a circuit board. The filter uses 100KHz as a bandwidth unit in the KHz frequency band and 100MHz as a bandwidth unit in the MHz frequency band, covering a frequency range of 100KHz to 1.5GHz.

[0027] Preferably, the input terminal and the output terminal of the filter in this embodiment both use 360-degree fully shielded RF connectors.

[0028] Preferably, the power module that provides power to various parts of the filter in this embodiment has a wide power input, supports DC110V / DC220V / AC220V input, and 5V / 12V / 24V output.

[0029] Preferably, the controller in the filter channel switching circuit of this embodiment adopts FPGA.

[0030] Preferably, the filter of this embodiment supports four filtering frequency bands and can be adapted to high-frequency current partial discharge sensors, ultra-high frequency partial discharge sensors, ultrasonic partial discharge sensors, and transient ground wave partial discharge sensors.

[0031] Partial discharge monitoring system embodiment of the present invention The partial discharge monitoring system of the present invention comprises a partial discharge sensor and a filter, the input port of the filter is connected to the output end of the partial discharge sensor, and the filter is referred to the above filter embodiment and will not be described in detail here.

[0032] The advantages of the present invention are: the filter can automatically identify the type of partial discharge monitoring sensor (high-frequency CT, ultrasonic, ultra-high frequency, etc.), can quickly switch the filter channel during the monitoring process, and automatically select the filter frequency band suitable for the real-time working conditions. The filter exists in the form of an independent module, which can greatly improve the electromagnetic shielding effect. The filter can realize the universalization of the partial discharge monitoring filter function, greatly enhance the anti-interference ability, effectively improve the detection reliability of the partial discharge monitoring system, reduce the risk of failure of high-voltage electrical equipment (such as GIS), and save costs. In addition, it is no longer necessary to manually design the filter, and the configuration efficiency is high.

Claims

1. A filter for partial discharge monitoring, characterized in that: The filter includes an input terminal, a sensor identification unit for identifying the type of a partial discharge sensor, a filter channel switching circuit and more than two filter channels in different working frequency bands. The input terminal of the filter is used to connect the output end of the partial discharge sensor. The filter channel switching circuit includes an input end and an output end connected to each filter channel. The input end of the filter channel switching circuit and the I / O port of the sensor identification unit are both connected to the input terminal of the filter. The filter channel switching circuit is communicatively connected to the sensor identification unit. The filter channel switching circuit is used to only conduct the filter channel adapted to the partial discharge sensor according to the type of the partial discharge sensor transmitted by the sensor identification unit.

2. The filter for partial discharge monitoring according to claim 1, characterized in that: The sensor identification unit includes a processor and a pulse signal generator and a signal receiving circuit connected to the processor. The pulse signal generator is used to send a pulse signal of a fixed amplitude to the partial discharge sensor. The signal receiving circuit is used to receive a reflected signal reflected from the partial discharge sensor. The processor is used to calculate the characteristic impedance of the partial discharge sensor based on the sent pulse signal and the reflected signal, and determine the type of the partial discharge sensor based on the characteristic impedance of the partial discharge sensor.

3. The filter for partial discharge monitoring according to claim 1, characterized in that: The filter channel switching circuit includes a controller and a switch switching unit. The controller controls the switch switching unit. The controller communicates with the sensor identification unit. The controller is used to control the switch switching unit according to the type of partial discharge sensor transmitted by the sensor identification unit to achieve that only the filter channel compatible with the partial discharge sensor is turned on.

4. The filter for partial discharge monitoring according to claim 1, characterized in that: The filter channel switching circuit is also used to cyclically conduct each filter channel in a time period after the partial discharge monitoring system starts to work and before the filter channel matching is completed.

5. The filter for partial discharge monitoring according to claim 3, characterized in that: The switch switching unit is a radio frequency switch.

6. A partial discharge monitoring system, the system comprising a partial discharge sensor, characterized in that: The system also includes a filter, which includes an input terminal, a sensor identification unit for identifying the type of partial discharge sensor, a filter channel switching circuit and more than two filter channels in different working frequency bands, the input terminal of the filter is connected to the output end of the partial discharge sensor, the filter channel switching circuit includes an input end and an output end connected to each filter channel, the input end of the filter channel switching circuit and the I / O port of the sensor identification unit are both connected to the input terminal of the filter, the filter channel switching circuit is communicatively connected to the sensor identification unit, and the filter channel switching circuit is used to only conduct the filter channel adapted to the partial discharge sensor according to the type of partial discharge sensor transmitted by the sensor identification unit.

7. The partial discharge monitoring system according to claim 6, characterized in that: The sensor identification unit includes a processor and a pulse signal generator and a signal receiving circuit connected to the processor. The pulse signal generator is used to send a pulse signal of a fixed amplitude to the partial discharge sensor. The signal receiving circuit is used to receive a reflected signal reflected from the partial discharge sensor. The processor is used to calculate the characteristic impedance of the partial discharge sensor based on the sent pulse signal and the reflected signal, and determine the type of the partial discharge sensor based on the characteristic impedance of the partial discharge sensor.

8. The partial discharge monitoring system according to claim 6, characterized in that: The filter channel switching circuit includes a controller and a switch switching unit. The controller controls the switch switching unit. The controller communicates with the sensor identification unit. The controller is used to control the switch switching unit according to the type of partial discharge sensor transmitted by the sensor identification unit to achieve that only the filter channel compatible with the partial discharge sensor is turned on.

9. The partial discharge monitoring system according to claim 6, characterized in that: The filter channel switching circuit is also used to cyclically conduct each filter channel in a time period after the partial discharge monitoring system starts to work and before the filter channel matching is completed.

10. The partial discharge monitoring system according to claim 8, characterized in that: The switch switching unit is a radio frequency switch.

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