CN115856528A - Switch cabinet local discharge pulse current detection positioning method - Google Patents
Switch cabinet local discharge pulse current detection positioning method Download PDFInfo
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- CN115856528A CN115856528A CN202211468598.8A CN202211468598A CN115856528A CN 115856528 A CN115856528 A CN 115856528A CN 202211468598 A CN202211468598 A CN 202211468598A CN 115856528 A CN115856528 A CN 115856528A
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Abstract
The invention relates to a detection and positioning method for local discharge pulse current of a switch cabinet, which comprises the steps of establishing a 3D simulation model containing the switch cabinet and a local discharge pulse current sensor, and establishing a simulation circuit diagram of the switch cabinet; setting different types of partial discharge pulse current sources at each part in the switch cabinet one by one, obtaining the simulated pulse signal waveform amplitude of each part of a plurality of measuring points, and establishing a database; acquiring time domain waveforms of partial discharge pulse current signals in a switch cabinet on site to obtain time domain waveform amplitudes of a plurality of measurement points; determining the position of the partial discharge based on a digital twinning simulation waveform amplitude calculation method; the precision of partial discharge positioning can be greatly improved, and a positioning result can be accurate to a certain component in the switch cabinet. The accuracy and the working efficiency of equipment insulation defect diagnosis prediction and operation and maintenance are greatly improved by realizing accurate positioning, and the safety and the reliability of the switch cabinet are greatly improved.
Description
Technical Field
The invention relates to a method for detecting and positioning local discharge pulse current of a switch cabinet, and belongs to the technical field of power distribution networks.
Background
The high-voltage switch cabinet is used as an important electrical device in a power distribution network of a power system. The main function of the switch cabinet is to open and close, control and protect electric equipment in the process of power generation, power transmission, power distribution and electric energy conversion of an electric power system. The components in the switch cabinet mainly comprise a circuit breaker, an isolating switch, a load switch, an operating mechanism, a mutual inductor, various protection devices and the like.
In the production, transportation, installation and maintenance processes of the high-voltage switch cabinet, defects such as cracks, metal burrs, scattered metal impurities and the like inevitably exist, and along with the long-term operation of the switch cabinet, the defects cause the local field intensity on the insulating surface or inside to be higher than the critical field intensity of the insulating medium, so that local discharge is caused. Meanwhile, the partial discharge phenomenon existing for a long time can also cause further deterioration of insulation and accelerate insulation failure.
The generation of partial discharge is accompanied by various physical phenomena such as sound, electricity, light, heat, and the like, and various partial discharge detection methods have been developed by monitoring these physical quantities reflecting the discharge phenomenon. At home and abroad, the commonly used detection methods mainly comprise an ultrasonic method, an ultrahigh frequency method and a transient-state to ground voltage method, and the local discharge positioning is generally carried out by the amplitude in the methods. The methods are external detection methods, and due to the fact that the local discharge signal propagation process is complex and the field interference is complex, the positioning accuracy of the methods is low and the errors are large. In the case of good detection conditions, it is also possible with these methods to determine only the side of the switch cabinet on which the partial discharge is located, but not which part of the interior of the switch cabinet the partial discharge is located. Inaccurate positioning and inaccurate guidance and maintenance decision.
The existing switch cabinet partial discharge positioning technology adopts a time domain positioning method to perform positioning according to the amplitude and time delay of a time domain waveform, but the method has extremely high requirement on the resolution of a measuring instrument, and due to the existence of interference, misjudgment and missed judgment are possibly caused to the information such as the amplitude, the first wave arrival time and the like of the waveform, so that the positioning precision is reduced.
Disclosure of Invention
The invention aims to provide a method for detecting and positioning the current of a local discharge pulse of a switch cabinet, so as to solve the problems in the background technology.
The technical scheme of the invention is as follows:
a local discharge pulse current detection positioning method for a switch cabinet comprises the following steps:
s1, establishing a 3D simulation model comprising a switch cabinet and a local discharge pulse current sensor, and acquiring capacitance of each part in the switch cabinet through electric field simulation, thereby establishing a switch cabinet simulation circuit diagram;
setting different types of partial discharge pulse current sources at each part in the switch cabinet one by one, obtaining the simulated pulse signal waveform amplitude of each part of a plurality of measuring points, and establishing a database;
s2, carrying out partial discharge signal detection on site, and acquiring a time domain waveform of a partial discharge pulse current signal in the switch cabinet to obtain time domain waveform amplitudes of a plurality of measurement points;
and S3, calculating the actually measured time domain waveform amplitude and the simulated pulse signal waveform amplitude based on a digital twin simulation waveform amplitude calculation method, and determining the position of the partial discharge.
Preferably, the database is an n × m matrix, n represents the number of components in the switchgear, and m represents the number of measurement points.
Preferably, the database is viewed as a set of n vectors, each vector containing M elements, denoted M i Marking:
M i ＝(U th1i ，U th2i …U thmi )，i＝1，2……n；
and (2) regarding the actually measured pulse current waveform amplitude of the switch cabinet at each measuring point as a vector, wherein each vector comprises m elements and is represented by S:
S＝(U ts1 ，U ts2 …U tsm )
calculating the S and Mi one by the following formula to calculate the maximum point as the positioning result:
D i ＝U th1i ·U ts1 +U th2i ·U ts2 +…+U thmi ·U tsm 。
the invention has the following beneficial effects:
the precision of partial discharge positioning can be greatly improved, and the positioning result can be accurate to a certain component in the switch cabinet. And the robustness of the positioning method is higher. After accurate positioning is realized based on the method, the accuracy and the working efficiency of equipment insulation defect diagnosis prediction and operation and maintenance are greatly improved, and the safety and reliability of the switch cabinet are greatly improved.
Drawings
FIG. 1 is a diagram of electrical connections in a switchgear cabinet of the present invention;
FIG. 2 is a schematic diagram of a technical scheme of the present invention;
FIG. 3 is an internal structure view of the high voltage switch cabinet of the present invention;
FIG. 4 is a circuit diagram of the high voltage switch cabinet simulation of the present invention;
fig. 5 is a database of local discharge pulse current signal waveform parameters of the high-voltage switch cabinet of the invention.
The reference numbers in the figures denote:
1. a busbar; 2. a circuit breaker; 3. a current transformer; 4. a lightning arrester; 5. a charged display; 6. a grounding disconnecting link; 7. a high voltage cable; 8. a coupling capacitor; 9. a pulse current coupling unit; 10. a high pressure sensor; 11. and (4) an isolating switch.
Detailed Description
The invention is described in detail below with reference to the figures and the specific embodiments.
The technical principle of the invention is as follows: when a certain component in the switch cabinet generates partial discharge and a pulse current signal reaches the detection coupling device, the transfer function of the pulse current signal depends on the impedance characteristics of lines and components in a propagation path; the time domain waveform amplitude of the signal obtained by the coupling device is directly related to the partial discharge position; and the component where the partial discharge is positioned can be mapped by performing time domain waveform correlation calculation by using the measured time domain waveform amplitude and the simulation waveform amplitude of the partial discharge pulse current signal.
Example (b):
the electrical wiring diagrams of the internal components of the high-voltage switch cabinet are respectively shown in fig. 1, and the high-voltage switch cabinet mainly comprises a busbar 1, a circuit breaker 2, a current transformer 3, a lightning arrester 4, an electrified display 5, a grounding disconnecting link 6 and a high-voltage cable 7. In order to couple the partial discharge pulse signal, a coupling capacitor 8 and a pulse current coupling unit 9 are arranged at the core phase hole of the switch cabinet.
The flow chart is shown in FIG. 2:
firstly, establishing a 3D simulation model comprising a switch cabinet and a partial discharge pulse current sensor, acquiring capacitance of each part through electric field simulation, calculating capacitance parameters by adopting two methods of parallel plate capacitance method calculation and electrostatic field finite element method calculation, thereby establishing a switch cabinet simulation circuit diagram, as shown in fig. 4, and successively setting different types of partial discharge pulse current sources at the positions of a busbar 1, a current transformer 3, a lightning arrester 4 and the like of the switch cabinet to obtain simulated time domain amplitude values of each part of a plurality of measurement points and establishing a database;
secondly, carrying out partial discharge signal detection on site, and acquiring a partial discharge pulse current signal time domain waveform in the switch cabinet to obtain signal amplitudes of a plurality of measurement points;
thirdly, waveform amplitude correlation calculation is carried out on the actually measured waveform and the simulated waveform, and the position of the partial discharge can be determined.
In simulation, local discharge sources are respectively arranged on each part (part number i, i =1,2, … …, n) of the switch cabinet, pulse current signals are obtained through simulation, and the waveform amplitude (U) of the pulse signals of each measuring point is extracted th ) And (4) parameter, establishing a signal waveform amplitude database. As shown in fig. 5, the database is an n × m matrix.
Measuring partial discharge signals in the switch cabinet to obtain time domain waveform amplitude U of pulse current signals of each measuring point ts1 ，U ts2 …U tsi 。
The database is viewed as a set of n vectors, each vector containing M elements, with M i Identification, namely:
Mi＝(U th1i ,U th2i …U thmi )，i＝1，2……n
and (2) regarding the actually measured pulse current waveform amplitude of the switch cabinet at each measuring point as a vector, wherein each vector comprises m elements and is represented by S, namely:
S＝(U ts1 ，U ts2 …U tsm )
calculating S and M one by one through an amplitude correlation calculation formula i And selecting the point with the maximum correlation calculation as a positioning result. The amplitude correlation calculation is calculated as follows:
D i ＝U th1i ·U ts1 +U th2i ·U ts2 +…+U thmi ·U tsm 。
the invention greatly improves the accuracy and the working efficiency of on-site partial discharge test and switch cabinet operation and maintenance, avoids equipment with defects from being put into operation, and greatly promotes the progress of electrician equipment test and detection technology.
In the aspect of economic benefit, if the core technology of the invention is industrially grounded and popularized in the market, the accuracy and efficiency of the partial discharge diagnosis of the switch cabinet are greatly improved, the probability of insulation fault of the switch cabinet is reduced, and the direct and indirect economic benefit is obvious.
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present specification and drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (3)
1. A local discharge pulse current detection positioning method for a switch cabinet is characterized by comprising the following steps: the method comprises the following steps:
s1, establishing a 3D simulation model comprising a switch cabinet and a local discharge pulse current sensor, and acquiring capacitance of each part in the switch cabinet through electric field simulation, thereby establishing a switch cabinet simulation circuit diagram;
setting different types of partial discharge pulse current sources at each part in the switch cabinet one by one, obtaining the simulated pulse signal waveform amplitude of each part of a plurality of measuring points, and establishing a database;
s2, carrying out partial discharge signal detection on site, and acquiring a time domain waveform of a partial discharge pulse current signal in the switch cabinet to obtain time domain waveform amplitudes of a plurality of measurement points;
and S3, calculating the actually measured time domain waveform amplitude and the simulated pulse signal waveform amplitude based on a digital twin simulation waveform amplitude calculation method, and determining the position of the partial discharge.
2. The method for detecting and positioning the current of the local discharge pulse of the switch cabinet as claimed in claim 1, wherein: the database is an n x m matrix, n represents the number of components in the switch cabinet, and m represents the number of measuring points.
3. The switch cabinet local discharge pulse current detection positioning method according to claim 2, characterized in that:
the database is viewed as a set of n vectors, each vector containing m elements, identified by Mi:
M i ＝(U th1i ,U th2i …Ut hmi )，i＝1，2……n；
and (2) regarding the actually measured pulse current waveform amplitude of the switch cabinet at each measuring point as a vector, wherein each vector comprises m elements and is represented by S:
S＝(U ts1 ，U ts2 …Ut sm )
calculating S and M one by the following formula i And taking the point with the maximum calculation as a positioning result:
D i ＝U th1i ·U ts1 +U th2i ·U ts2 +…+U thmi ·U tsm 。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211468598.8A CN115856528A (en) | 2022-11-22 | 2022-11-22 | Switch cabinet local discharge pulse current detection positioning method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211468598.8A CN115856528A (en) | 2022-11-22 | 2022-11-22 | Switch cabinet local discharge pulse current detection positioning method |
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| CN115856528A true CN115856528A (en) | 2023-03-28 |
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| CN202211468598.8A Pending CN115856528A (en) | 2022-11-22 | 2022-11-22 | Switch cabinet local discharge pulse current detection positioning method |
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| CN (1) | CN115856528A (en) |
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- 2022-11-22 CN CN202211468598.8A patent/CN115856528A/en active Pending
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