CN113917297A - Cable detection device and cable detection system - Google Patents
Cable detection device and cable detection system Download PDFInfo
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- CN113917297A CN113917297A CN202111183093.2A CN202111183093A CN113917297A CN 113917297 A CN113917297 A CN 113917297A CN 202111183093 A CN202111183093 A CN 202111183093A CN 113917297 A CN113917297 A CN 113917297A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials
- G01R31/1263—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation
- G01R31/1272—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation of cable, line or wire insulation, e.g. using partial discharge measurements
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Abstract
The present invention relates to a cable detection device and a cable detection system. The cable detection device comprises a partial discharge detection module, a grounding circulation detection module and a combining module, wherein the partial discharge detection module is used for detecting a partial discharge signal of a cable and outputting a corresponding first voltage, the grounding circulation detection module is used for detecting a grounding circulation signal of the cable and outputting a corresponding second voltage, the combining module comprises a low-frequency isolation unit and a high-frequency isolation unit, the low-frequency isolation unit effectively ensures the output effect of the second voltage, the high-frequency isolation unit effectively ensures the output result of the first voltage, therefore, the cable detection device can obtain the superposed signal of the first voltage and the second voltage at the common end of the high-frequency isolation unit and the low-frequency isolation unit, therefore, only one group of lines is needed to obtain the partial discharge signal and the grounding circulating current signal of the cable, and therefore the monitoring cost of the cable is reduced.
Description
Technical Field
The present invention relates to power cable insulation state detection, and more particularly, to a cable detection device and a cable detection system.
Background
The partial discharge is a discharge phenomenon caused by the breakdown of a local area in an insulating medium, is a main cause of insulation degradation, is an important sign and expression form of the insulation degradation, is closely related to the degradation of an insulating material and the breakdown process of an insulator, and can effectively reflect latent defects and faults of the internal insulation of equipment.
The grounding circulation monitoring is that circulation data is used as monitoring quantity, circulation is generally formed on a metal sheath, when a cable core transmits current, corresponding electromagnetic fields exist around the cable core, and according to the electromagnetic induction principle, induction voltage appears on the metal sheath of the cable, so that circulation is obtained. In the normal state, the metal sheath cannot form an effective path with the ground due to the existence of the grounding resistance, so the circulating current is very small and can be ignored. The circulating current in the case of a fault is larger than the circulating current in the case of normal operation, and therefore, the operation monitoring of the cable line can be realized by monitoring the grounding circulating current.
At present, in order to monitor the operation of a cable line, at least two groups of lines need to be separately installed to obtain a partial discharge signal and a ground circulating signal of the cable, and then analysis is performed according to the partial discharge signal and the ground circulating signal of the cable, which results in higher monitoring cost of the cable.
Disclosure of Invention
Accordingly, there is a need for a cable detection device and a cable detection system with low cable monitoring cost.
In a first aspect, a cable detection apparatus is provided, including:
the partial discharge detection module is used for detecting a partial discharge signal of the cable and outputting a corresponding first voltage; the grounding loop detection module is used for detecting a grounding loop signal of the cable and outputting a corresponding second voltage; the combiner module comprises a low-frequency isolation unit and a high-frequency isolation unit; the input end of the low-frequency isolation unit is connected with the partial discharge detection module, the input end of the high-frequency isolation unit is connected with the grounding circulating current detection module, and the output end of the high-frequency isolation unit is connected with the output end of the low-frequency isolation unit and used for combining and outputting a superposed signal of the first voltage and the second voltage.
In one embodiment, the partial discharge detection module includes a first magnetic core and a first winding, the first winding is sleeved on the periphery of the first magnetic core, and the first magnetic core is used for being sleeved on the ground wire of the cable.
In one embodiment, the partial discharge detection module further includes a metal housing, and the first magnetic core and the first winding are disposed inside the metal housing.
In one embodiment, the ground circulating current detection module includes a second magnetic core and a second winding, the second winding is sleeved on the periphery of the second magnetic core, and the second magnetic core is used for being sleeved on the ground wire of the cable.
In one embodiment, the low frequency isolation unit includes a first capacitor.
In one embodiment, the high frequency isolation unit includes an inductor.
In one embodiment, the high-frequency isolation device further comprises a filtering module, an input end of the filtering module is connected with an output end of the ground circulating current detection module, and an output end of the filtering module is connected with an input end of the high-frequency isolation unit.
In one embodiment, the ground circulating current detection module includes a second voltage output terminal and a first ground terminal, the input terminals of the high-frequency isolation unit include a second voltage input terminal and a second ground terminal, the filtering module includes a resistor and a second capacitor, a first terminal of the resistor is connected to the second voltage output terminal and the second voltage input terminal, a first terminal of the second capacitor is connected to the second voltage output terminal and the second voltage input terminal, and the first ground terminal, the second ground terminal, a second terminal of the resistor, and a second terminal of the second capacitor are grounded.
In one embodiment, the resistance of the resistor is 1 ohm, and the capacitance of the second capacitor is 150 microfarads.
In a second aspect, a cable detection system is provided, comprising: a cable detection device as claimed in any one of the above first aspects; and the signal processing device is connected with the output end of the high-frequency isolation unit or the output end of the low-frequency isolation unit and is used for acquiring and displaying the superposed signals.
The cable detection device comprises a partial discharge detection module, a grounding circulation detection module and a combining module, wherein the partial discharge detection module is used for detecting a partial discharge signal of the cable and outputting a corresponding first voltage, the grounding circulation detection module is used for detecting a grounding circulation signal of the cable and outputting a corresponding second voltage, the combining module comprises a low-frequency isolation unit and a high-frequency isolation unit, the low-frequency isolation unit effectively ensures the output effect of the second voltage, the high-frequency isolation unit effectively ensures the output result of the first voltage, therefore, the cable detection device can obtain the superposed signal of the first voltage and the second voltage at the common end of the high-frequency isolation unit and the low-frequency isolation unit, therefore, only one group of lines is needed to obtain the partial discharge signal and the grounding circulating current signal of the cable, and therefore the monitoring cost of the cable is reduced.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments or the conventional technologies of the present application, the drawings used in the descriptions of the embodiments or the conventional technologies will be briefly introduced below, it is obvious that the drawings in the following descriptions are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic structural view of a cable detection device of a first embodiment;
FIG. 2a is a schematic structural diagram of a housing according to an embodiment;
FIG. 2b is a schematic structural diagram of the first magnetic ring and the second magnetic ring inside the housing according to an embodiment;
FIG. 3 is a schematic structural diagram of a cable inspection device according to a second embodiment;
FIG. 4 is a schematic structural diagram of a cable inspection device according to a third embodiment;
FIG. 5 is a schematic structural diagram of a cable inspection device according to a fourth embodiment;
fig. 6 is a schematic structural diagram of a cable detection device according to an embodiment.
Detailed Description
To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Embodiments of the present application are set forth in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
It will be understood that, as used herein, the terms "first," "second," and the like may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, a first resistance may be referred to as a second resistance, and similarly, a second resistance may be referred to as a first resistance, without departing from the scope of the present application. The first resistance and the second resistance are both resistances, but they are not the same resistance.
It is to be understood that "connection" in the following embodiments is to be understood as "electrical connection", "communication connection", and the like if the connected circuits, modules, units, and the like have communication of electrical signals or data with each other.
As used herein, the singular forms "a", "an" and "the" may include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises/comprising," "includes" or "including," etc., specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Also, as used in this specification, the term "and/or" includes any and all combinations of the associated listed items.
In practical application, generally, a circulating current sensor is used for detecting a grounding circulating current signal of a cable, a partial discharge sensor is used for detecting a partial discharge signal of the cable, the circulating current sensor and the partial discharge sensor are both provided with independent signal transmission loops, output signals of the two sensors are directly connected in parallel to a signal output port, and the signal output port cannot output signals because the impedance of the signal output port is larger than the self impedance of the parallel loop.
For the above reasons, the present invention provides a cable detection device. Referring to fig. 1, a cable detection apparatus according to a first embodiment of the present disclosure is shown, which may include a partial discharge detection module 120, a ground circulating current detection module 140, and a combining module 160.
The partial discharge detection module 120 is configured to detect a partial discharge signal of the cable and output a corresponding first voltage. The partial discharge detection module 120 can sense a partial discharge signal of the cable, and can convert the sensed signal into a first voltage corresponding to the partial discharge signal according to a certain rule and output the first voltage. It should be noted that the frequency information of the first voltage output by the partial discharge detection module 120 corresponds to the frequency of the partial discharge signal. In one embodiment, the frequency of the first voltage output by the partial discharge detection module 120 is the same as the frequency of the current flowing through the core of the cable. In one embodiment, the partial discharge detection module 120 is a Rogowski coil (HFCT). It will be appreciated that the rogowski coil is a toroidal coil uniformly wound on a non-ferromagnetic material, in use, with the earth wire of the cable passing through the toroidal coil. The Rogowski coil has the characteristics of real-time measurement of current, high response speed and no saturation, and is suitable for measuring partial discharge signals.
The ground loop detection module 140 is configured to detect a ground loop signal of the cable and output a corresponding second voltage. The ground loop detection module 140 can sense a ground loop signal of the cable, and can convert the sensed signal into a second voltage corresponding to the ground loop signal according to a certain rule to output the second voltage. It should be noted that the signal transmitted by the core of the cable is a low-frequency signal, and the ground circulating signal corresponds to the signal transmitted by the core of the cable, so that the second voltage output by the ground circulating detection module 140 is also a low-frequency signal. In one embodiment, the frequency of the second voltage output by the ground circulating current detecting module 140 is consistent with the frequency of the current flowing through the cable core. In one embodiment, the ground circulating current detection module 140 may include a ground circulating current sensor for measuring a metal sheath ground circulating current signal of the cable, and determining the operation condition of the cable by measuring a low frequency current.
The combining module 160 includes a low frequency isolation unit 162 and a high frequency isolation unit 164. The input end of the low-frequency isolation unit 162 is connected to the partial discharge detection module 120, the input end of the high-frequency isolation unit 164 is connected to the ground circulating current detection module 140, and the output end of the high-frequency isolation unit 164 is connected to the output end of the low-frequency isolation unit 162, and is configured to output a superimposed signal of the first voltage and the second voltage in a combined manner. It should be noted that the low frequency isolation unit 162 is used for isolating low frequency signals, since the core of the cable transmits a low frequency signal (e.g. 50Hz), the ground circulating signal corresponds to the signal transmitted by the core, and the second voltage corresponds to the ground circulating signal, so that the second voltage is also a low frequency signal, and the low frequency isolation unit 162 can isolate the second voltage. The high frequency isolation unit 164 is used for isolating the high frequency signal, since the frequency band of the partial discharge signal is in the range of 0.3MHz to 30MHz, the partial discharge signal is a high frequency signal, and the first voltage corresponds to the partial discharge signal, so the first voltage is a high frequency signal, and the high frequency isolation unit 164 can isolate the first voltage. The combination module 160 enables the first voltage to be output from the output terminal of the low frequency isolation unit 162 and the output terminal of the second voltage high frequency isolation unit 164, and since the output terminal of the high frequency isolation unit 164 is connected to the output terminal of the low frequency isolation unit 162, the combination module 160 can output a superimposed signal of the first voltage and the second voltage.
The cable detection device provided by the embodiment of the application comprises a partial discharge detection module, a grounding circulation detection module and a combining module, wherein the partial discharge detection module is used for detecting a partial discharge signal of a cable and outputting a corresponding first voltage, the grounding circulation detection module is used for detecting a grounding circulation signal of the cable and outputting a corresponding second voltage, the combining module comprises a low-frequency isolation unit and a high-frequency isolation unit, the low-frequency isolation unit effectively ensures the output effect of the second voltage, the high-frequency isolation unit effectively ensures the output result of the first voltage, therefore, the cable detection device can obtain the superposed signal of the first voltage and the second voltage at the common end of the high-frequency isolation unit and the low-frequency isolation unit, therefore, only one group of lines is needed to obtain the partial discharge signal and the grounding circulating current signal of the cable, and the detection cost of the cable is reduced.
Meanwhile, the cable detection device provided by the embodiment ensures that the partial discharge signal and the grounding circulating current signal are not distorted and have no phase deviation, and completely maintains the integrity of the partial discharge signal and the grounding circulating current signal. Furthermore, the cable detection device has high reliability and can be widely applied to various detection environments.
The partial discharge detection module in the above embodiment is configured to detect a partial discharge signal of the cable and output a corresponding first voltage, and the ground circulating current detection module is configured to detect a ground circulating current signal of the cable and output a corresponding second voltage.
In one embodiment, the partial discharge detection module may include a first magnetic core and a first winding, the first winding is sleeved on a periphery of the first magnetic core, and the first magnetic core is used for being sleeved on a ground wire of the cable to detect a partial discharge signal of the cable and output a corresponding first voltage. It should be noted that the winding refers to a combination of a plurality of coils wound with enamel wire or the like, and the ground wire of the cable is connected to the metal sheath and the ground terminal of the cable for discharging the induced voltage accumulated on the metal sheath. The first magnetic core can respond to a high-frequency signal with a frequency band ranging from 0.3MHz to 30MHz, and generally speaking, the frequency band of the partial discharge signal ranges from 0.3MHz to 30MHz, that is, the first magnetic core can respond to the partial discharge signal. In one embodiment, the first core is a core of high frequency soft magnetic material, which has good permeability in the frequency band from 0.3MHz to 30MHz and is insensitive to 50Hz current signals.
In one embodiment, a first magnetic core sheathed with a first winding may be placed in proximity to the cable. It should be noted that the first magnetic core is spaced from the cable by a distance that ensures that the first winding is able to output a voltage signal corresponding to the partial discharge signal. In one embodiment, the partial discharge detection module may further include a housing, and the first magnetic core and the first winding are disposed inside the housing. In one embodiment, the housing defines a through-hole sized to allow the electrical connection of the cable to pass therethrough. In one embodiment, the housing defines an output slot for the first winding such that the first winding is connectable to the input of the low frequency isolation unit.
In an embodiment, the ground circulating current detection module may include a second magnetic core and a second winding, the second winding is sleeved on a periphery of the second magnetic core, and the second magnetic core is used for being sleeved on a ground wire of the cable to detect a ground circulating current signal of the cable and output a corresponding second voltage. The frequency to which the second magnetic core can respond comprises the frequency corresponding to the current flowing through the cable core. In one embodiment, the second core has good sensitivity to a power frequency current signal of 50Hz but is insensitive to partial discharge signals of 0.3MHz to 30 MHz.
In one embodiment, a second magnetic core sheathed with a second winding may be placed near the cable. It should be noted that the second magnetic core is spaced from the cable by a distance that ensures that the second winding is able to output a voltage signal corresponding to the ground circulating signal. In one embodiment, the ground circulating current detection module may further include a housing, and the second magnetic core and the second winding are disposed inside the housing. In one embodiment, the housing defines a through-hole sized to allow a ground wire of the cable to pass therethrough. In one embodiment, the housing defines an output slot for the second winding such that the second winding is connectable to the input of the high frequency isolation unit.
In one embodiment, as shown in fig. 2a and 2b, the first magnetic core 202 peripherally sleeved with the first winding and the second magnetic core 204 peripherally sleeved with the second winding are disposed inside the same housing 206, so that the cable detection device can be more convenient. In one embodiment, the housing 206 is perforated with a through hole sized to allow a ground wire of a cable to pass through. In one embodiment, the housing 206 is slotted with output slots for the first winding and the second winding such that the first winding can be connected to the input of the low frequency isolation unit and the second winding can be connected to the input of the high frequency isolation unit.
In an embodiment, the housing in the above embodiments may be a metal housing, and the metal housing may avoid external magnetic field interference, so that the output first voltage and the output second voltage may more accurately reflect the partial discharge signal and the ground circulating signal of the cable. In one embodiment, the metal shell has better sealing property, wear resistance and mechanical strength, and can better protect the first magnetic core, the first winding, the second magnetic core and the second winding. In one embodiment, the surface of the metal shell is smooth and has no sharp corners, so that the risk of injury of detection personnel using the partial discharge detection module and the grounding circulation detection module can be reduced.
The low-frequency isolation unit of the above embodiment is used to isolate a low-frequency ground circulating current signal, and the high-frequency isolation unit is used to isolate a high-frequency partial discharge signal.
In one embodiment, the high frequency isolation unit may include an inductor. The first end of the inductor is connected with the output end of the grounding circulating current detection module, and the second end of the inductor is connected with the output end of the low-frequency isolation unit. The first voltage is isolated through the inductor, and the output effect of the second voltage is guaranteed.
In one embodiment, the low frequency isolation unit may include a first capacitor. The first end of the first capacitor is connected with the output end of the partial discharge detection module, and the second end of the first capacitor is connected with the output end of the high-frequency isolation unit. The second voltage can be isolated through the first capacitor, and the output effect of the first voltage is guaranteed.
Therefore, the second end of the inductor is connected with the second end of the first capacitor, and the superposed signal of the first voltage and the second voltage can be output, so that the partial discharge signal and the grounding circulating current signal of the cable can be obtained, and the operation condition of the cable can be analyzed and judged. The output of the superposed signal of the first voltage and the second voltage can be realized by arranging the first capacitor and the inductor, and the structure is simple, easy to realize and low in cost.
Referring to fig. 3, a cable detection apparatus according to a second embodiment of the present disclosure is shown, as shown in fig. 3, the cable detection apparatus may include a partial discharge detection module 120, a ground circulating current detection module 140, a combining module 160, and a filtering module 320. The partial discharge detection module 120, the ground circulating current detection module 140, and the combining module 160 are described in detail in the above embodiments, and are not described herein again. The input end of the filtering module 320 is connected to the output end of the ground circulating current detecting module 140, and the output end of the filtering module 320 is connected to the input end of the high frequency isolating unit 164. It should be noted that the filtering module 320 is used for filtering the interference signal carried by the second voltage.
Referring to fig. 4, a cable detection apparatus according to a third embodiment of the present disclosure is shown, as shown in fig. 4, the cable detection apparatus may include a partial discharge detection module 120, a ground circulating current detection module 140, a combining module 160, and a filtering module 320. The ground circulating current detection module 140 includes a second voltage output terminal OUT1 and a first ground terminal GND1, the input terminals of the high-frequency isolation unit 164 include a second voltage input terminal IN1 and a second ground terminal GND2, and the filter module 320 includes a resistor R1 and a second capacitor C2. Specifically, a first end of the resistor R1 is connected to the second voltage output terminal OUT1 and the second voltage input terminal IN1, a first end of the second capacitor C2 is connected to the second voltage output terminal OUT1 and the second voltage input terminal IN1, and the first ground terminal GND1, the second ground terminal GND2, a second end of the resistor and a second end of the capacitor are grounded. In one embodiment, the resistor R1 may have a resistance of 1 ohm, and the second capacitor C2 may have a capacitance of 150 microfarads.
IN one embodiment, as shown IN fig. 4, the partial discharge detection module 120 includes a first voltage output terminal OUT2 and a third ground terminal GND3, the input terminals of the low frequency isolation unit 162 include a first voltage input terminal IN2 and a fourth ground terminal GND4, the first voltage output terminal is connected to the first input terminal, and the third ground terminal and the fourth ground terminal are grounded.
As shown in fig. 5, which illustrates a cable test apparatus provided in the fourth embodiment of the present application, as shown in fig. 5, the cable test apparatus may include a high-frequency current sensor 502, a ground loop current sensor 504, a first capacitor C1, an inductor L1, a second capacitor C2, and a resistor R1. The first voltage output end of the high-frequency current sensor 502 is connected to the first end of the first capacitor C1, the second end of the first capacitor C2 is connected to the second end of the inductor L1, the first end of the inductor L1 is connected to the first end of the resistor R1, the first end of the second capacitor C2, the second voltage output end of the ground loop current sensor 504, the first ground end of the ground loop current sensor 504, the third ground end of the high-frequency current sensor 502, the second end of the resistor R1, and the first end of the second capacitor C2, respectively, and grounded. It should be noted that a second terminal of the first capacitor C1 is connected to a second terminal of the inductor L1, and is used for outputting a superimposed signal of the first voltage and the second voltage. In one embodiment, the output port Uo of the cable detection device is disposed at a communication position between the second end of the first capacitor C1 and the second end of the inductor L1, so as to output a superimposed signal of the first voltage and the second voltage.
According to the embodiment of the application, the direct parallel coupling output of the superposed signals by the high-frequency current sensor and the grounding circulating current sensor is realized, the distortion and the phase deviation of the partial discharge signals and the grounding circulating current signals are avoided, the integrity of the partial discharge signals and the grounding circulating current signals is completely reserved, the realization mode is simple, the reliability is high, and the method can be widely applied to the cable field detection environment.
Referring to fig. 6, which illustrates a cable detection system provided in an embodiment of the present application, as shown in fig. 6, the cable detection device may include a cable detection device 602 and a signal processing device 604 provided in any of the above embodiments. The signal processing device 604 is connected to the output end of the high frequency isolation unit 164 or the output end of the low frequency isolation unit 162 of the cable detection device 602, and is used for acquiring and displaying the superimposed signal. The signal processing device 602 may be configured to process the superimposed signal and/or analyze the superimposed signal to determine whether the cable is damaged. In one embodiment, when the current threshold is 5% of the core current of the cable, the metal sheath insulation of the cable is considered damaged when the ground circulation current of the cable is greater than the current threshold. It can be understood that the method for determining whether the cable is damaged may be set according to actual situations, and the embodiment of the present application does not limit this.
In one embodiment, the signal processing apparatus may include one or more of an analog-to-digital conversion unit, a filtering unit, and a voltage adjusting unit. It will be appreciated that the appropriate functional block may be selected according to the processing operations to be performed on the superimposed signal.
In one embodiment, as shown in fig. 6, the cable detection system may further include a communication device 606, where the communication device 606 is connected to the output end of the signal processing device 604 and is used to transmit the data processed by the signal processing device 604 to the background, so that the background personnel may obtain and store the corresponding cable data.
In the description herein, references to the description of "some embodiments," "other embodiments," "desired embodiments," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, a schematic description of the above terminology may not necessarily refer to the same embodiment or example.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A cable testing device, comprising:
the partial discharge detection module is used for detecting a partial discharge signal of the cable and outputting a corresponding first voltage;
the grounding loop detection module is used for detecting a grounding loop signal of the cable and outputting a corresponding second voltage;
the combiner module comprises a low-frequency isolation unit and a high-frequency isolation unit; the input end of the low-frequency isolation unit is connected with the partial discharge detection module, the input end of the high-frequency isolation unit is connected with the grounding circulating current detection module, and the output end of the high-frequency isolation unit is connected with the output end of the low-frequency isolation unit and used for combining and outputting a superposed signal of the first voltage and the second voltage.
2. The cable detection device according to claim 1, wherein the partial discharge detection module includes a first magnetic core and a first winding, the first winding is disposed around the first magnetic core, and the first magnetic core is disposed around a ground wire of the cable.
3. The cable detection device of claim 2, wherein the partial discharge detection module further comprises a metal housing, and the first magnetic core and the first winding are disposed inside the metal housing.
4. The apparatus according to claim 1, wherein the ground circulating current detecting module includes a second magnetic core and a second winding, the second winding is disposed around the second magnetic core, and the second magnetic core is disposed around a ground wire of the cable.
5. The cable detection apparatus of claim 1, wherein the low frequency isolation unit comprises a first capacitor.
6. The cable detection apparatus of claim 1, wherein the high frequency isolation unit comprises an inductor.
7. The cable detection device according to claim 1, further comprising a filtering module, wherein an input end of the filtering module is connected to an output end of the ground circulating current detection module, and an output end of the filtering module is connected to an input end of the high frequency isolation unit.
8. The apparatus according to claim 7, wherein the ground circulating current detection module includes a second voltage output terminal and a first ground terminal, the input terminals of the high frequency isolation unit include a second voltage input terminal and a second ground terminal, the filtering module includes a resistor and a second capacitor, a first terminal of the resistor is connected to the second voltage output terminal and the second voltage input terminal, a first terminal of the second capacitor is connected to the second voltage output terminal and the second voltage input terminal, and a second terminal of the first ground terminal, the second terminal of the resistor, and a second terminal of the second capacitor are grounded.
9. The cable detection apparatus of claim 8, wherein the resistor has a resistance of 1 ohm and the second capacitor has a capacitance of 150 microfarads.
10. A cable detection system, comprising:
the cable detection device of any one of claims 1 to 9;
and the signal processing device is connected with the output end of the high-frequency isolation unit or the output end of the low-frequency isolation unit and is used for acquiring and displaying the superposed signals.
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