CN113138323B - Partial discharge type recognition device - Google Patents
Partial discharge type recognition device Download PDFInfo
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- CN113138323B CN113138323B CN202110271555.XA CN202110271555A CN113138323B CN 113138323 B CN113138323 B CN 113138323B CN 202110271555 A CN202110271555 A CN 202110271555A CN 113138323 B CN113138323 B CN 113138323B
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- 230000036961 partial effect Effects 0.000 title claims abstract description 148
- 238000001514 detection method Methods 0.000 claims abstract description 135
- 238000012545 processing Methods 0.000 claims abstract description 43
- 239000003990 capacitor Substances 0.000 claims description 42
- 239000000725 suspension Substances 0.000 claims description 5
- 230000035945 sensitivity Effects 0.000 abstract description 6
- 238000005259 measurement Methods 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- 238000007667 floating Methods 0.000 description 6
- 230000007547 defect Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 239000004020 conductor Substances 0.000 description 4
- 230000005684 electric field Effects 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 230000002238 attenuated effect Effects 0.000 description 3
- 230000015556 catabolic process Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
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- 239000002184 metal Substances 0.000 description 2
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- 230000005540 biological transmission Effects 0.000 description 1
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- 239000003973 paint Substances 0.000 description 1
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Classifications
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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
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
- G01R1/02—General constructional details
- G01R1/04—Housings; Supporting members; Arrangements of terminals
- G01R1/0408—Test fixtures or contact fields; Connectors or connecting adaptors; Test clips; Test sockets
Abstract
The application relates to a partial discharge type identification device, which comprises a detection circuit and a processing module; the access end of the detection circuit is connected with the switch cabinet shell, and the output end of the detection circuit is connected with the processing module; the detection circuit is used for determining the equivalent impedance of the detection circuit according to electromagnetic waves generated by partial discharge of the switch cabinet; the processing module is used for identifying the output voltage waveform of the detection circuit and adjusting the equivalent impedance of the detection circuit according to the identification result until the output voltage waveform of the detection circuit reaches a peak value; and the processing module is also used for determining the type of partial discharge of the switch cabinet according to the output voltage of the detection circuit and the frequency of the output voltage waveform under the condition that the output voltage waveform reaches the peak value. The device has high sensitivity, the processor can obtain relatively stable and clear waveforms when the waveforms of the output voltages reach the peak values, and can obtain accurate voltage values of the output voltages and frequencies of the waveforms according to the waveforms, so that the accuracy of identifying the partial discharge types is improved.
Description
Technical Field
The application relates to the technical field of partial discharge testing, in particular to a partial discharge type identification device.
Background
The switch cabinet is an important component of the power system and plays a double role of controlling a circuit and protecting the safety of the system. However, partial discharge is very easy to occur on the surfaces of components such as cable terminals, lightning arresters, insulating struts and the like in the switch cabinet, and effective identification of the type of the partial discharge is a precondition for accurately evaluating the hazard degree of the partial discharge degree of the switch cabinet and selecting a correct treatment scheme.
At present, the local discharge capacity of a switch cabinet is detected by mostly depending on an ultrahigh frequency current detection technology, an ultrasonic detection technology, a transient voltage detection technology, an ultraviolet and infrared detection technology and the like, and then the type of the local discharge is judged according to the size of the local discharge capacity.
However, since partial discharge is a very weak electrical phenomenon, the sensitivity of the above technique for detecting partial discharge is not high, resulting in a low accuracy in identifying the type of partial discharge.
Disclosure of Invention
The embodiment of the application provides a partial discharge type identification device, which has high sensitivity when partial discharge detection is carried out, so that the partial discharge type can be accurately identified.
A partial discharge type recognition device comprises a detection circuit and a processing module; the access end of the detection circuit is connected with the switch cabinet shell, and the output end of the detection circuit is connected with the processing module;
The detection circuit is used for determining the equivalent impedance of the detection circuit according to electromagnetic waves generated by partial discharge of the switch cabinet;
The processing module is used for identifying the output voltage waveform of the detection circuit and adjusting the equivalent impedance of the detection circuit according to the identification result until the output voltage waveform of the detection circuit reaches a peak value;
And the processing module is also used for determining the type of partial discharge of the switch cabinet according to the output voltage of the detection circuit and the frequency of the output voltage waveform under the condition that the output voltage waveform reaches the peak value.
In one embodiment, the detection circuit includes: a first tunable inductor and a first tunable capacitor;
the first end of the first adjustable inductor is attached to the switch cabinet shell; the second end of the first adjustable inductor is connected with the first end of the first adjustable capacitor; the second end of the first adjustable capacitor is grounded, and the first end of the first adjustable inductor is an access end of the detection circuit.
In one embodiment, the detection circuit further includes: the second adjustable inductor is connected in parallel with the first adjustable capacitor and then connected in series with the first adjustable inductor.
In one embodiment, adjusting the equivalent impedance of the detection circuit until the output voltage waveform of the detection circuit reaches a peak value according to the identification result includes:
and adjusting the first adjustable inductor, the first adjustable capacitor or the second adjustable inductor according to the identification result until the output voltage waveform of the detection circuit reaches a peak value.
In one embodiment, determining the type of partial discharge of the switchgear from the output voltage of the detection circuit and the frequency of the output voltage waveform includes:
under the condition that the frequency of the output voltage waveform is smaller than a first preset threshold value, calculating according to the voltage value when the output voltage waveform reaches the peak value to obtain the local discharge capacity of the switch cabinet;
And determining the type of the partial discharge of the switch cabinet according to the form of the output voltage waveform and the partial discharge quantity of the switch cabinet.
In one embodiment, determining the type of partial discharge of the switchgear based on the morphology of the output voltage waveform and the partial discharge amount of the switchgear includes:
When the waveform of the output voltage is stable and the partial discharge capacity of the switch cabinet is within a first preset range, determining that the type of partial discharge of the switch cabinet is corona discharge;
And when the waveform of the output voltage is stable and the partial discharge capacity of the switch cabinet is within a second preset range, determining that the type of the partial discharge of the switch cabinet is air gap discharge.
In one embodiment, determining the type of partial discharge of the switchgear from the output voltage of the detection circuit and the frequency of the output voltage waveform includes:
under the condition that the frequency of the output voltage waveform is larger than a first preset threshold value, calculating according to the voltage value when the output voltage waveform reaches the peak value to obtain the local discharge capacity of the switch cabinet;
and determining the type of the partial discharge of the switch cabinet according to the partial discharge quantity of the switch cabinet.
In one embodiment, determining the type of partial discharge of the switchgear according to the amount of partial discharge of the switchgear includes:
when the partial discharge amount of the switch cabinet is within a third preset range, determining that the type of partial discharge of the switch cabinet is creeping discharge;
when the partial discharge capacity of the switch cabinet is in a fourth preset range, the type of the partial discharge of the switch cabinet is determined to be suspension point discharge.
In one embodiment, the first preset threshold of frequency is 200MHZ.
In one embodiment, the apparatus further comprises: and the display module is used for displaying the waveform of the output voltage.
The application provides a partial discharge type identification device, which comprises a detection circuit and a processing module; the access end of the detection circuit is connected with the switch cabinet shell, and the output end of the detection circuit is connected with the processing module; the detection circuit is used for determining the equivalent impedance of the detection circuit according to electromagnetic waves generated by partial discharge of the switch cabinet; the processing module is used for identifying the output voltage waveform of the detection circuit and adjusting the equivalent impedance of the detection circuit according to the identification result until the output voltage waveform of the detection circuit reaches a peak value; and the processing module is also used for determining the type of partial discharge of the switch cabinet according to the output voltage of the detection circuit and the frequency of the output voltage waveform under the condition that the output voltage waveform reaches the peak value. Because electromagnetic waves appear when the switch cabinet generates partial discharge phenomenon, one part of the electromagnetic waves can be shielded by a metal shell of the switch cabinet, the rest part of the electromagnetic waves can leak from holes on the shell of the switch cabinet to the surface of the shell of the switch cabinet to generate voltage signals on the surface of the shell, and then the voltage signals are converted into current signals through the shell of the switch cabinet and enter an input end of receiving equipment; the voltage signal is very weak, the value of the voltage signal is in the range of a few millivolts to a few volts, and the voltage signal can be attenuated due to the output impedance on the shell of the switch cabinet, so that the waveform of the voltage signal is distorted, distorted and the like, the current signal received by receiving equipment such as a sensor in the prior art is weaker, the receiving equipment cannot obtain relatively stable and clear output waveform, accurate measurement data cannot be obtained, and the recognized partial discharge type has larger error. According to the application, the equivalent impedance of the detection circuit connected with the switch cabinet shell is regulated, so that the equivalent impedance is equal to the output impedance on the switch cabinet shell, the output impedance on the switch cabinet shell is counteracted, the voltage signal on the switch cabinet shell cannot generate excessive attenuation due to the output impedance on the switch cabinet shell, so that the detection circuit can better distinguish the current signal, further, the current signal with the strongest amplitude and generated by partial discharge in the switch cabinet is detected, a relatively stable and clear waveform is output at the output end, the measurement sensitivity of the detection circuit is high, and the optimal partial discharge detection effect is realized. And the processing module can acquire accurate measurement values according to stable and clear waveforms, so that the accuracy of partial discharge type identification is improved.
Drawings
FIG. 1 is a schematic diagram of a partial discharge type recognition device according to an embodiment;
FIG. 2 is a schematic diagram of a partial discharge type recognition device according to another embodiment;
FIG. 3 is a schematic diagram of a partial discharge type recognition device according to another embodiment;
FIG. 4 is a schematic diagram of partial discharge type identification flow in one embodiment.
FIG. 5 is a schematic diagram of a partial discharge type recognition device according to another embodiment;
Reference numerals illustrate:
11. a detection circuit; 12. a processing module; 101. a first adjustable inductance;
102. a first tunable capacitor; 103. a second adjustable inductance; 13. and a display module.
Detailed Description
The present application will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present application more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.
In one embodiment, as shown in fig. 1, there is provided a partial discharge type recognition apparatus including a detection circuit 11 and a processing module 12; the access end of the detection circuit 11 is connected with the switch cabinet shell, and the output end of the detection circuit 11 is connected with the processing module 12;
A detection circuit 11 for determining an equivalent impedance of the detection circuit 11 according to electromagnetic waves generated by partial discharge of the switch cabinet;
a processing module 12, configured to identify an output voltage waveform of the detection circuit 11, and adjust an equivalent impedance of the detection circuit 11 according to the identification result until the output voltage waveform of the detection circuit 11 reaches a peak value;
The processing module 12 is further configured to determine a type of partial discharge of the switch cabinet according to the output voltage of the detection circuit 11 and the frequency of the output voltage waveform when the output voltage waveform reaches a peak value.
The detection circuit 11 may include components such as a resistor, an inductor, a capacitor, and a switch, and the components are combined in a certain connection manner to form the detection circuit 11, where the number of the resistor, the inductor, the capacitor, and the switch in the detection circuit 11 may be only one, or may include a plurality of resistors, inductors, capacitors, and switches; the connection method may be, for example, a connection method of series connection, parallel connection, a combination of series connection and parallel connection, or the like. The detection circuit 11 may include only a capacitor and an inductor, and the number of the capacitor and the inductor may be one or more, and the connection may be, for example, a series connection, a parallel connection, a combination of series connection and parallel connection, or the like. The capacitance may be an adjustable capacitance, the inductance may be an adjustable inductance, and the plurality of capacitances in the detection circuit 11 may be all or part of the adjustable capacitance; the plurality of inductors in the detection circuit 11 may be all or part of the adjustable inductors, which is not limited in the present application. The processing module 12 may include an oscilloscope and a computer device, where the detection circuit 11 is connected to the oscilloscope and the computer device, respectively, the oscilloscope is also connected to the computer device, and is capable of displaying a waveform of an output voltage of the detection circuit 11 and corresponding data, and the computer device is capable of reading the data on the oscilloscope, performing processing such as calculation and judgment on the data, determining how to adjust the detection circuit 11 and control the detection circuit 11 to perform corresponding adjustment according to the results of calculation and judgment, so that the waveform displayed on the oscilloscope reaches a peak value. The processor may also be an oscilloscope with a processing chip, which not only can display the waveform of the output voltage of the detection circuit 11 and the corresponding data, but also can perform processing such as calculation, judgment, etc. on the data, so that the oscilloscope can determine how to adjust the detection circuit 11 and control the detection circuit 11 to perform corresponding adjustment according to the results of calculation, judgment, etc. so as to make the waveform displayed on the oscilloscope reach the peak value. The processor may be a computer device, which may obtain the waveform of the output voltage and the data corresponding to the waveform according to the detection result of the detection circuit 11, and perform processing such as calculation, judgment, etc. on the data, so that the computer device may determine how to adjust the detection circuit 11 and control the detection circuit 11 to perform corresponding adjustment according to the calculation, judgment, etc. result, so that the waveform of the output voltage reaches the peak value, and the computer device may further include a display unit, which may display the waveform of the output voltage and the corresponding data, which is not limited in the present application.
When the partial discharge phenomenon occurs in the switch cabinet, electromagnetic waves are generated in the switch cabinet, a part of the electromagnetic waves can leak to the surface of the shell of the switch cabinet through a hole in the shell of the switch cabinet, a voltage signal is generated on the surface of the shell, and then the voltage signal is converted into a current signal through the shell of the switch cabinet and enters an input end of receiving equipment; wherein the value of the voltage signal is very weak in the range of a few millivolts to a few volts. And the voltage signal can be attenuated due to the output impedance on the switch cabinet shell, so that the current signal transmitted to the input end of the receiving equipment is weaker. The output impedance on the switch cabinet shell can comprise an equivalent capacitor and an equivalent inductor, wherein the equivalent capacitor is mainly the equivalent capacitor of a paint film represented by the switch cabinet shell and the shell, and the equivalent capacitor is larger than the equivalent inductor, so that the switch cabinet shell externally presents capacitance characteristics, and the application enables the detection circuit 11 to externally present inductance characteristics by adjusting the adjustable inductor, the adjustable capacitor or the resistor in the detection circuit 11, namely, the impedance of the detection circuit 11 and the switch cabinet shell are equal in size and opposite in direction, the output impedance on the switch cabinet shell is counteracted, the detection circuit 11 can detect a current signal with the strongest amplitude, at the moment, the voltage waveform output by the output end of the detection circuit 11 reaches a peak value, so that the processing module 12 can obtain a relatively stable and clear waveform, and the voltage value of the output voltage of the detection circuit 11 and the frequency of the waveform can be obtained according to the waveform. And finally, determining the partial discharge type of the switch cabinet according to the frequency and the discharge quantity characteristics of different partial discharge types. The adjustment detection circuit 11 may be all components in the adjustment detection circuit 11, or may be part of components in the adjustment detection circuit 11; the frequencies and discharge amounts of different partial discharge types are characterized by: the frequency of corona discharge is in the range of 100-250 MHz, the discharge capacity is in the range of 50-65 pC, and the like; the frequency of the suspension potential discharge is within the range of 200-900 MHz, and the discharge capacity is within the range of 280-320 pC; creeping discharge: the frequency is within the range of 200-900 MHz, and the discharge capacity is within the range of 12-25 pC; air gap discharge: the frequency is in the range of 150-1500 MHz, and the discharge capacity is in the range of 55-300 pC. It should be noted that, the determination of the frequency of different partial discharge types and the range of the discharge amount is based on experimental results, and is common knowledge of those skilled in the art, which is not described in detail herein.
The application provides a partial discharge type identification device, which comprises a detection circuit and a processing module; the access end of the detection circuit is connected with the switch cabinet shell, and the output end of the detection circuit is connected with the processing module; the detection circuit is used for determining the equivalent impedance of the detection circuit according to electromagnetic waves generated by partial discharge of the switch cabinet; the processing module is used for identifying the output voltage waveform of the detection circuit and adjusting the equivalent impedance of the detection circuit according to the identification result until the output voltage waveform of the detection circuit reaches a peak value; and the processing module is also used for determining the type of partial discharge of the switch cabinet according to the output voltage of the detection circuit and the frequency of the output voltage waveform under the condition that the output voltage waveform reaches the peak value. Because electromagnetic waves appear when the switch cabinet generates partial discharge phenomenon, one part of the electromagnetic waves can be shielded by a metal shell of the switch cabinet, the rest part of the electromagnetic waves can leak from holes on the shell of the switch cabinet to the surface of the shell of the switch cabinet to generate voltage signals on the surface of the shell, and then the voltage signals are converted into current signals through the shell of the switch cabinet and enter an input end of receiving equipment; the voltage signal is very weak, the value of the voltage signal is in the range of a few millivolts to a few volts, and the voltage signal can be attenuated due to the output impedance on the shell of the switch cabinet, so that the waveform of the voltage signal is distorted, distorted and the like, the current signal received by receiving equipment such as a sensor in the prior art is weaker, the receiving equipment cannot obtain relatively stable and clear output waveform, accurate measurement data cannot be obtained, and the recognized partial discharge type has larger error. According to the application, the equivalent impedance of the detection circuit connected with the switch cabinet shell is regulated, so that the equivalent impedance is equal to the output impedance on the switch cabinet shell, the output impedance on the switch cabinet shell is counteracted, the voltage signal on the switch cabinet shell cannot generate excessive attenuation due to the output impedance on the switch cabinet shell, so that the detection circuit can better distinguish the current signal, further, the current signal with the strongest amplitude and generated by partial discharge in the switch cabinet is detected, a relatively stable and clear waveform is output at the output end, the measurement sensitivity of the detection circuit is high, and the optimal partial discharge detection effect is realized. And the processing module can acquire accurate measurement values according to stable and clear waveforms, so that the accuracy of partial discharge type identification is improved.
In one embodiment, as shown in fig. 2, this embodiment is one possible implementation of the detection circuit 11, and the detection circuit 11 includes a first tunable inductor 101 and a first tunable capacitor 102;
A first end of the first adjustable inductor 101 is attached to the switch cabinet housing; the second end of the first adjustable inductor 101 is connected with the first end of the first adjustable capacitor 102; the second terminal of the first tunable capacitor 102 is grounded.
The detection circuit 11 includes a first adjustable inductor 101 and a first adjustable capacitor 102, which are connected in series, where a first end of the first adjustable inductor 101 is an access end of the detection circuit 11, that is, the first end of the first adjustable inductor 101 is connected with a switch cabinet shell, and the connection may be contact connection, optionally, the detection circuit 11 further includes a patch, where the patch is attached to the switch cabinet shell, and the first adjustable inductor 101 is electrically connected with the patch through a wire, where the patch may be a magnetic patch, and then may be well attached to the switch cabinet shell without help of an external force, and may be optionally moved to a predetermined position, so that how to fix the detection circuit 11 on the switch cabinet shell is not needed to be considered too much, thereby improving convenience of use. The first adjustable inductor 101 and the first adjustable capacitor 102 form an LC oscillating circuit, and adjusting the size of the first adjustable inductor 101 and/or the first adjustable capacitor 102 can enable the detection circuit 11 to externally present an inductance characteristic, and resonate with the output impedance on the switch cabinet shell, that is, the impedance of the first adjustable inductor and the first adjustable capacitor is equal in size and opposite in direction, and the result can be represented by whether the waveform of the output voltage reaches a peak value or not. Therefore, during the adjustment, whether the waveform of the output voltage reaches the peak value or not can be detected by the processing module 12, so as to determine the adjustment mode of the first adjustable inductor 101 and the first adjustable capacitor 102, and the adjustment of the first adjustable inductor 101 and the first adjustable capacitor 102 is stopped until the processing module 12 detects that the waveform of the output voltage reaches the peak value. At this time, the amplitude of the current signal detected at the detection circuit 11 is maximum.
The application provides a partial discharge type identification device, wherein a detection circuit in the device comprises a first adjustable inductor and a first adjustable capacitor, the circuit is simple in structure, and the output impedance on a switch cabinet shell can be counteracted by adjusting the first adjustable inductor and the first adjustable capacitor, so that the detection circuit can easily detect weak voltage signals on the switch cabinet shell, and the sensitivity for detecting partial discharge is high.
In another embodiment, as shown in fig. 3, this embodiment is another possible implementation of the detection circuit, and the detection circuit further includes: the second adjustable inductor is connected in parallel with the first adjustable capacitor and then connected in series with the first adjustable inductor.
The frequency of the electromagnetic signal radiated to the switch cabinet shell is high or low after the partial discharge phenomenon occurs, so that the frequency of the voltage signal generated on the switch cabinet shell is high or low, and the frequency of the current signal converted by the switch cabinet shell is high or low. When most of the current signals are low-frequency current signals, a few high-frequency current signals will interfere with the low-frequency current signals, so that the detection circuit 11 cannot easily detect the current signals, and the output end of the detection circuit 11 cannot output a relatively clear and stable output voltage waveform, so that the high-frequency current signals need to be blocked, and the high-frequency current signals are prevented from interfering with the low-frequency current signals. The implementation mode can be that the second adjustable inductor 103 is turned up, the first adjustable capacitor 102 is turned down at the same time, so that few high-frequency voltage signals are blocked by the first adjustable capacitor 102, and most low-frequency current signals can pass through the first adjustable inductor 101 and the second adjustable inductor 103, so that the waveform of the output voltage at the output end of the detection circuit 11 reaches a peak value; similarly, when most of the current signals are high-frequency current signals, a few low-frequency current signals will interfere with the high-frequency current signals, so that the detection circuit 11 cannot easily detect the current signals, and the output end of the detection circuit 11 cannot output a relatively clear and stable output voltage waveform, so that the low-frequency current signals need to be blocked, and the low-frequency current signals are prevented from interfering with the high-frequency current signals. The implementation manner may be that by adjusting the second adjustable inductor 103 and simultaneously adjusting the first adjustable capacitor 102, a few low-frequency voltage signals are blocked by the second adjustable inductor 103, and most low-frequency current signals can pass through the first adjustable inductor 101 and the first adjustable capacitor 102, so that the waveform of the output voltage at the output end of the detection circuit 11 reaches a peak value. In turn, the processing module 12 is enabled to obtain accurate measurement values to identify the partial discharge type.
The application provides a partial discharge type identification device, wherein a detection circuit in the device also comprises a second adjustable inductor, and the output path of a voltage signal is switched by adjusting the second adjustable inductor and the first adjustable capacitor so as to eliminate the interference of a low-frequency voltage signal on a high-frequency voltage signal or eliminate the interference of the high-frequency voltage signal on the low-frequency voltage signal, thereby ensuring the waveform quality of the output voltage of the detection circuit and providing guarantee for the follow-up accurate determination of the partial discharge type according to the waveform.
In one embodiment, the embodiment is a possible implementation of adjusting the equivalent impedance of the detection circuit until the output voltage waveform of the detection circuit reaches a peak value according to the identification result, including:
the first adjustable inductor 101, the first adjustable capacitor 102 or the second adjustable inductor 103 is adjusted according to the identification result until the output voltage waveform of the detection circuit 11 reaches a peak value.
For example, the first adjustable inductor 101, the first adjustable capacitor 102 and/or the second adjustable inductor may be adjusted independently, two components may be adjusted, all components may be adjusted, the adjustment may be increased or decreased, specifically, after the processing module 12 recognizes the output voltage waveform of the detecting circuit 11, how to adjust each component in the detecting circuit 11 is determined according to the waveform form, and the detecting circuit 11 may trigger the corresponding adjustment according to the adjustment signal sent by the processing module 12.
The application provides a partial discharge type identification device, wherein a detection circuit in the device adjusts a first adjustable inductor, a first adjustable capacitor and/or a second adjustable inductor according to an adjusting signal sent by a processing module, and the adjustment is stopped until the processing module detects that the waveform of output voltage reaches a peak, so that the identification process of the partial discharge type is more intelligent, manual participation is not needed, the identification efficiency is higher, meanwhile, identification errors caused by artificial factors are avoided, and the identification accuracy is high.
In one embodiment, shown in fig. 4, which is one possible implementation of determining the type of partial discharge of the switchgear according to the output voltage of the detection circuit 11 and the frequency of the output voltage waveform, comprises:
under the condition that the frequency of the output voltage waveform is smaller than a first preset threshold value, calculating according to the voltage value when the output voltage waveform reaches the peak value to obtain the local discharge capacity of the switch cabinet;
And determining the type of the partial discharge of the switch cabinet according to the form of the output voltage waveform and the partial discharge quantity of the switch cabinet.
The first preset threshold value of the frequency may be determined according to previous experimental data of partial discharges of different types, including corona discharge, floating potential discharge, creeping discharge and air gap discharge, each partial discharge has different characteristics of partial discharge frequency and discharge amount, and in the case that the frequency of the output voltage waveform is smaller than the first preset threshold value, the four types of partial discharges may be divided into two large categories, and then corona discharge and air gap discharge may be determined according to the form of the output voltage waveform and the partial discharge amount of the switch cabinet, wherein the discharge amounts under different pressure values may be determined according to a voltage value-discharge amount map pair, which may also be generated according to experimental data, which is not described in detail in the present application.
Optionally, continuing to refer to fig. 4, determining the type of the partial discharge of the switch cabinet according to the form of the output voltage waveform and the partial discharge amount of the switch cabinet includes:
When the waveform of the output voltage is stable and the partial discharge capacity of the switch cabinet is within a first preset range, determining that the type of partial discharge of the switch cabinet is corona discharge;
And when the waveform of the output voltage is unstable and the partial discharge capacity of the switch cabinet is within a second preset range, determining that the type of the partial discharge of the switch cabinet is air gap discharge.
For example, the above-mentioned four types of partial discharge are divided into two major categories, and then further identification is performed, where the identification may be determined according to the waveform form of the output voltage and the partial discharge amount of the switch cabinet. For example: when the waveform of the output voltage is stable and the partial discharge capacity of the switch cabinet is in the range of 50-65 pC, determining the type of partial discharge of the switch cabinet as corona discharge; when the waveform of the output voltage is unstable and the partial discharge capacity of the switch cabinet is in the range of 55-300 pC, the type of the partial discharge of the switch cabinet is determined to be air gap discharge. The corona discharge is often caused by high-voltage conductors around the gas, for example, high-voltage wires of equipment such as a high-voltage transmission line are exposed to the outside for a long time, so that the wires are aged, corona discharge is easy to cause, the corona discharge presents the characteristic of an uneven electric field, and a continuous discharge phenomenon is generated under the uneven electric field, so that when the partial discharge type of the switch cabinet is identified as corona discharge, the high-voltage wires in the switch cabinet can be inspected and corresponding treatment is performed according to the inspection result. The air gap discharge exists mainly in the solid insulating medium, and when the insulating medium is produced and processed, design defects such as materials, processes and the like can be avoided, so that quality defects exist in the insulating medium, such as doping air, other impurities and the like in the medium. When the insulating medium is subjected to high voltage, the internal defects of the insulating medium can directly cause the breakdown of a local area so as to generate air gap discharge, wherein the size of the air gap, the defect condition, the type of air gap gas and the like can have different influences on the air gap discharge. When the partial discharge type of the switch cabinet is identified as air gap discharge, the insulation medium in the switch cabinet can be checked and processed correspondingly according to the checking result.
In one embodiment, continuing with fig. 4, which is one possible implementation of determining the type of partial discharge of the switchgear from the output voltage of the detection circuit 11 and the frequency of the output voltage waveform, comprises:
under the condition that the frequency of the output voltage waveform is larger than a first preset threshold value, calculating according to the voltage value when the output voltage waveform reaches the peak value to obtain the local discharge capacity of the switch cabinet;
and determining the type of the partial discharge of the switch cabinet according to the partial discharge quantity of the switch cabinet.
For example, in case the frequency of the output voltage waveform is greater than the first preset threshold value, it may be determined that the type of partial discharge of the switchgear is a floating potential discharge or a creeping discharge based only on the partial discharge amount of the switchgear.
Optionally, continuing to fig. 4, determining the type of the partial discharge of the switchgear according to the partial discharge amount of the switchgear includes:
when the partial discharge amount of the switch cabinet is within a third preset range, determining that the type of partial discharge of the switch cabinet is creeping discharge;
when the partial discharge capacity of the switch cabinet is in a fourth preset range, the type of the partial discharge of the switch cabinet is determined to be suspension point discharge.
The method includes the steps that when the partial discharge capacity of the switch cabinet is in the range of 280-320 pC, the type of partial discharge of the switch cabinet is determined to be suspension potential discharge; when the partial discharge amount of the switch cabinet is in the range of 12-25 pC, the type of the partial discharge of the switch cabinet is determined to be creeping discharge. The floating discharge is mainly caused by the fact that one conductor part in the high-voltage equipment has certain design defects or poor contact in a certain place, the part is positioned between the high-voltage electrode and the low-voltage electrode, partial voltage is obtained according to the impedance ratio of the position of the part to generate the discharge, the potential on the conductor part is the floating potential, if the conductor has the potential, the fact that the field intensity exists in the vicinity is concentrated can indicate that certain damage is caused to an insulating medium, namely the fact that the floating discharge easily occurs to the high-potential part in the switch cabinet is indicated, and when the partial discharge type of the switch cabinet is identified as the floating discharge, the high-potential part in the switch cabinet can be checked and corresponding processing is carried out according to the checking result. A phenomenon which is generated on the surface of an insulating medium during creeping discharge is a special gas discharge phenomenon, and is common in places such as power cables, end parts of insulating sleeves, motor windings and the like. If the internal electric field intensity of the medium is not higher than the air gap at the edge of the electrode and the breakdown voltage of the medium along the surface is not very high, the phenomenon of surface discharge can be generated on the surface of the insulating medium, and the surface discharge can be influenced by voltage waveforms, electric field distribution, medium states and climatic conditions, so when the partial discharge type of the switch cabinet is identified as the surface discharge, the method can be used for checking the insulating medium such as a power cable, the end part of an insulating sleeve and the like in the switch cabinet and performing corresponding processing according to the checking result.
The application provides a partial discharge type recognition device which is used for recognizing four types of partial discharge according to different determining factors, so that the recognition is more targeted, and the recognition is more efficient by dividing the major types first and then carrying out recognition in different modes.
Optionally, the first preset threshold of frequency is 200MHZ. The first preset threshold is determined according to the frequency ranges of partial discharge of different types, the types of partial discharge can be divided into two main types by the first preset threshold, then each type of partial discharge type is respectively identified according to different factors, so that the classification of the four types of partial discharge according to the first preset threshold is more reasonable, a cut identification mode is avoided, and the identification efficiency of the partial discharge type can be improved.
In one embodiment, as shown in fig. 5, which is one possible implementation of the partial discharge type identifying device, the device further includes: and a display module 13, wherein the display module 13 is used for displaying the waveform of the output voltage. Specifically, the partial discharge type recognition device displays the output voltage waveform output by the output end of the detection circuit 11 and the data corresponding to the waveform through the display module 13, so that the waveform and the data can be checked conveniently and manually, the accuracy of the partial discharge type recognition device in recognizing the partial discharge type can be verified conveniently, and the accuracy of the partial discharge type recognition is further improved.
The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.
Claims (10)
1. A partial discharge type recognition device, characterized in that the device comprises a detection circuit and a processing module; the access end of the detection circuit is connected with the switch cabinet shell, and the output end of the detection circuit is connected with the processing module; the detection circuit includes: a first tunable inductor and a first tunable capacitor; the first end of the first adjustable inductor is attached to the switch cabinet shell, the second end of the first adjustable inductor is connected with the first end of the first adjustable capacitor, the second end of the first adjustable capacitor is grounded, and the first end of the first adjustable inductor is an access end of the detection circuit; the detection circuit further includes: the second adjustable inductor is connected with the first adjustable capacitor in parallel and then connected with the first adjustable inductor in series;
the detection circuit is used for determining the equivalent impedance of the detection circuit according to electromagnetic waves generated by partial discharge of the switch cabinet;
The processing module is used for identifying the output voltage waveform of the detection circuit and adjusting the first adjustable inductor, the first adjustable capacitor or the second adjustable inductor according to the identification result until the output voltage waveform of the detection circuit reaches a peak value; the second adjustable inductor and the first adjustable capacitor are adjusted to eliminate interference of a low-frequency voltage signal to a high-frequency voltage signal or eliminate interference of the high-frequency voltage signal to the low-frequency voltage signal;
And the processing module is also used for determining the type of the partial discharge of the switch cabinet according to the output voltage of the detection circuit and the frequency of the output voltage waveform under the condition that the output voltage waveform reaches the peak value.
2. The device of claim 1, wherein the detection circuit further comprises a patch attached to the switch cabinet housing, the first adjustable inductance being electrically connected to the patch by a wire.
3. The device of claim 2, wherein the patch is a magnetic patch.
4. The apparatus of claim 1, wherein the processing module comprises an oscilloscope and a computer device, the detection circuit being coupled to the oscilloscope and the computer device, respectively, the oscilloscope being coupled to the computer device.
5. The apparatus of claim 1, wherein said determining the type of partial discharge of the switchgear based on the output voltage of the detection circuit and the frequency of the output voltage waveform comprises:
Calculating to obtain the local discharge capacity of the switch cabinet according to the voltage value when the output voltage waveform reaches the peak value under the condition that the frequency of the output voltage waveform is smaller than a first preset threshold value;
and determining the type of the partial discharge of the switch cabinet according to the form of the output voltage waveform and the partial discharge quantity of the switch cabinet.
6. The apparatus of claim 5, wherein said determining the type of partial discharge of the switchgear based on the morphology of the output voltage waveform and the partial discharge amount of the switchgear comprises:
When the waveform of the output voltage is stable and the partial discharge capacity of the switch cabinet is within a first preset range, determining that the type of the partial discharge of the switch cabinet is corona discharge;
and when the waveform of the output voltage is stable and the partial discharge capacity of the switch cabinet is within a second preset range, determining that the type of the partial discharge of the switch cabinet is air gap discharge.
7. The apparatus of claim 1, wherein said determining the type of partial discharge of the switchgear based on the output voltage of the detection circuit and the frequency of the output voltage waveform comprises:
Calculating to obtain the local discharge capacity of the switch cabinet according to the voltage value when the output voltage waveform reaches the peak value under the condition that the frequency of the output voltage waveform is larger than a first preset threshold value;
and determining the type of the partial discharge of the switch cabinet according to the partial discharge quantity of the switch cabinet.
8. The apparatus of claim 7, wherein the determining the type of the partial discharge of the switchgear based on the partial discharge amount of the switchgear comprises:
When the partial discharge amount of the switch cabinet is within a third preset range, determining that the type of the partial discharge of the switch cabinet is creeping discharge;
And when the partial discharge capacity of the switch cabinet is within a fourth preset range, determining that the type of the partial discharge of the switch cabinet is suspension point discharge.
9. The apparatus according to claim 5 or 7, wherein the first preset threshold value of the frequency is 200MHZ.
10. The apparatus of claim 1, wherein the apparatus further comprises: and the display module is used for displaying the waveform of the output voltage.
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