CN112526405B - Fault diagnosis method and related device for capacitor switching-out system - Google Patents
Fault diagnosis method and related device for capacitor switching-out system Download PDFInfo
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Abstract
The application discloses a fault diagnosis method and a related device for a capacitor switching-out system, wherein the waveform amplitude of a three-phase terminal voltage of a capacitor basically keeps a stable state and always keeps a three-phase symmetrical relation with a neutral point potential when the capacitor is not in fault, so that whether the capacitor is in fault or not is judged according to the three-phase load terminal voltage of the capacitor when the capacitor is switched off and exits the system; if the capacitor fails, removing the high-frequency harmonic component and the direct-current component of the correction quantity of the end voltage of the three-phase load, calculating the correction quantity of the end voltage of the three-phase load according to the average value of the envelope curves of the high-frequency harmonic component and the direct-current component, and setting the phase with the maximum correction quantity as a failure phase; then, judging the current direction of the determined fault phase capacitor; and finally, determining the specific capacitance of the fault bridge arm according to the current direction of the fault capacitance bridge arm, so that whether the capacitor is in a fault state or not can be diagnosed under the condition that the internal fuse protection and the bridge difference current protection cannot normally act, and the specific fault position of the capacitor can be diagnosed.
Description
Technical Field
The present disclosure relates to the field of capacitor fault diagnosis technologies, and in particular, to a fault diagnosis method and related apparatus for switching out a system of a capacitor.
Background
The state of the capacitors in the substation plays a critical role in the operation of the grid system. The traditional parallel capacitor generally adopts a protection mode that internal fuse protection is used as main protection and bridge type current differential protection is used as backup protection, but has larger defects.
When the capacitor element breaks down, the internal fuse wire is blown out in an overcurrent mode, so that the fault capacitor element is isolated, and when the broken parallel capacitor elements reach a certain number, the internal fuse wire cannot normally isolate the fault, so that the short circuit accident of the whole string section is caused. Further when the capacitor breaks down, the current flowing through the bridge difference current transformer is large, the transformer is easily damaged, the fault occurrence condition cannot be judged normally, and the probability of misoperation and operation rejection is large. Even when the capacitor in a normal working state exits from the system through the opening of the circuit breaker, overvoltage can be generated on the first opening phase to threaten the insulation of the capacitor, and the inrush current and the overvoltage can cause the capacitor to be damaged in more serious insulation when the circuit breaker is switched on.
Therefore, it is of great research interest to provide a method for diagnosing capacitor faults.
Disclosure of Invention
The embodiment of the application provides a fault diagnosis method and a related device when a capacitor is switched out of a system, and the fault diagnosis method and the related device are used for diagnosing whether the capacitor is in a fault state or not and diagnosing the specific fault position of the capacitor under the condition that internal fuse protection and bridge differential current protection cannot normally act.
In view of the above, the present application provides, in a first aspect, a fault diagnosis method for a capacitor cut-out system, the method including:
s1, when the capacitor is opened and exits the system, acquiring the voltage of a three-phase load end and the voltage of a three-phase neutral point of the capacitor;
s2, subtracting the three-phase load end voltage from the three-phase neutral point voltage to obtain a first correction quantity of the three-phase load end voltage, substituting the first correction quantity into a three-phase symmetric relation discriminant to calculate, and if the value of the three-phase symmetric relation discriminant is not zero, the capacitor is in fault;
s3, filtering the high-frequency harmonic component and the direct-current component of the first correction quantity to obtain a second correction quantity;
s4, substituting the weighted mean value of the upper half cycle envelope curve of the second correction quantity and the weight value of the harmonic attenuation time constant into a voltage correction quantity calculation formula for calculation to obtain the three-phase load end voltage correction quantity, and setting the phase with the maximum correction quantity in the three-phase load end voltage correction quantity as a fault phase;
and S5, acquiring the current direction of each bridge arm capacitor in the fault phase, wherein the bridge arm capacitors are fault bridge arm capacitors when the current direction of the bridge arm capacitors is the inflow direction.
Optionally, after step S2, the method further includes:
and acquiring the fault time of the capacitor according to the oscillogram corresponding to the three-phase load terminal voltage.
Optionally, the filtering out the high-frequency harmonic component and the direct-current component of the first correction amount to obtain a second correction amount specifically includes:
and taking the periodic average value of the high-frequency harmonic component as a third correction amount of the voltage of the three-phase load, and obtaining the second correction amount when the envelope average value of the third correction amount is within a preset threshold interval.
Optionally, the three-phase symmetric relation discriminant is as follows:
xA(n)+xB(n)+xC(n)＝0；
wherein the content of the first and second substances,
in the formula, xA(n)、xB(n)、xC(n) a-phase, B-phase, and C-phase correction amounts of a first correction amount of the three-phase load terminal voltage, respectively; u shapeA(n)、UB(n)、UC(n) the voltages of the A phase, the B phase, the C phase and the U phase of the three-phase load terminal voltage are respectivelyNAnd (n) is a three-phase neutral point voltage.
Optionally, the voltage correction amount calculation formula is:
in the formula, y3(n) is the correction amount of the three-phase load terminal voltage, kiIs the weight of the harmonic decay time constant, T is the harmonic decay time, e(+)And n voltage sampling points are the upper half-cycle envelope curve of the second correction, and i is a voltage sampling point.
A second aspect of the present application provides a fault diagnosis apparatus for capacitor tap-out system, the apparatus comprising:
the device comprises an acquisition unit, a control unit and a control unit, wherein the acquisition unit is used for acquiring the voltage of a three-phase load end and the voltage of a three-phase neutral point of a capacitor when the capacitor is switched off and exits a system;
a first judging unit, configured to subtract the three-phase load terminal voltage from the three-phase neutral point voltage to obtain a first correction amount of the three-phase load terminal voltage, substitute the first correction amount into a three-phase symmetric relation discriminant to calculate, and if a value of the three-phase symmetric relation discriminant is not zero, cause the capacitor to malfunction;
the calculation unit is used for filtering out the high-frequency harmonic component and the direct-current component of the first correction quantity to obtain a second correction quantity;
the second judgment unit is used for substituting the weighted mean value of the envelope curve of the upper half cycle of the second correction quantity and the weight value of the harmonic attenuation time constant into a voltage correction quantity calculation formula for calculation to obtain the voltage correction quantity of the three-phase load end, and setting the phase with the maximum correction quantity in the voltage correction quantity of the three-phase load end as a fault phase;
and the third judging unit is used for acquiring the current direction of each bridge arm capacitor in the fault phase, and when the current direction of the bridge arm capacitor is the inflow direction, the bridge arm capacitor is the fault bridge arm capacitor.
Optionally, the method further comprises: a fourth judgment unit;
and the time for the capacitor to break down is obtained according to the oscillogram corresponding to the three-phase load terminal voltage.
Optionally, the computing unit is specifically configured to:
and taking the periodic average value of the high-frequency harmonic component as a third correction amount of the voltage of the three-phase load, and obtaining the second correction amount when the envelope average value of the third correction amount is within a preset threshold interval.
A third aspect of the present application provides a fault diagnosis apparatus for capacitor switching-out system, the apparatus including a processor and a memory:
the memory is used for storing program codes and transmitting the program codes to the processor;
the processor is adapted to perform the steps of the method for fault diagnosis in a capacitor switching-out system as described in the first aspect above, according to instructions in the program code.
A fourth aspect of the present application provides a computer-readable storage medium for storing program code for executing the method for diagnosing a fault when a capacitor is switched out of a system according to the first aspect.
According to the technical scheme, the embodiment of the application has the following advantages:
in an embodiment of the present application, a fault diagnosis method for a capacitor switching-out system is provided, including: s1, when the capacitor is opened and exits the system, acquiring the voltage of a three-phase load end and the voltage of a three-phase neutral point of the capacitor; s2, subtracting the three-phase load end voltage from the three-phase neutral point voltage to obtain a first correction quantity of the three-phase load end voltage, substituting the first correction quantity into a three-phase symmetric relation discriminant to calculate, and if the value of the three-phase symmetric relation discriminant is not zero, enabling the capacitor to be in fault; s3, filtering the high-frequency harmonic component and the direct-current component of the first correction quantity to obtain a second correction quantity; s4, substituting the weighted mean value of the envelope curve of the upper half cycle of the second correction quantity and the weight value of the harmonic attenuation time constant into a voltage correction quantity calculation formula for calculation to obtain the correction quantity of the end voltage of the three-phase load, and setting the phase with the maximum correction quantity in the correction quantity of the end voltage of the three-phase load as a fault phase; and S5, acquiring the current direction of each bridge arm capacitor in the fault phase, wherein the bridge arm capacitors are fault bridge arm capacitors when the current direction of the bridge arm capacitors is the inflow direction.
The application is used for the fault diagnosis method when the capacitor is switched out of the system, the capacitor is used as a diagnosis environment when the capacitor is switched off and exits the system, and the basic characteristics of the breaker when the breaker is switched off are utilized: the three-phase end voltage waveform amplitude of the capacitor basically keeps a stable state, and the three-phase symmetrical relation with the neutral point potential is always kept when the capacitor is not in fault, so that whether the capacitor is in fault or not is judged according to the three-phase load end voltage of the capacitor when the capacitor is switched off and exits the system; if the capacitor fails, removing the high-frequency harmonic component and the direct-current component of the correction quantity of the end voltage of the three-phase load, calculating the correction quantity of the end voltage of the three-phase load according to the average value of the envelope curves of the high-frequency harmonic component and the direct-current component, and setting the phase with the maximum correction quantity as a failure phase; and then judging the current direction of the determined fault phase capacitor, wherein the discharging current of the fault capacitor bridge arm only flows through the capacitor bridge arm connected in parallel with the fault capacitor bridge arm, and the direction of the discharging current flows from the non-fault bridge arm to the fault bridge arm, so that the specific fault bridge arm capacitor is determined according to the current direction, and whether the capacitor is in a fault state or not can be diagnosed and the specific fault position of the capacitor can be diagnosed under the condition that the internal fuse protection and the bridge difference current protection cannot normally act.
Drawings
Fig. 1 is a schematic flowchart of a first embodiment of a fault diagnosis method for a capacitor switching-out system according to an embodiment of the present application;
fig. 2 is a schematic flowchart of a second embodiment of a fault diagnosis method for a capacitor switching-out system according to an embodiment of the present application;
fig. 3 is a schematic structural diagram of an embodiment of a fault diagnosis device for a capacitor switching-out system provided in an embodiment of the present application.
Detailed Description
In order to make the technical solutions of the present application better understood, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Referring to fig. 1, a first embodiment of a fault diagnosis method for a capacitor switching-out system according to the present application includes:
The three-phase load terminal voltage of the capacitor, that is, the load terminal voltage of A, B, C three phases, and the neutral point refers to the common point of the star connection in the three-phase or multi-phase ac system.
And 102, subtracting the three-phase load terminal voltage from the three-phase neutral point voltage to obtain a first correction quantity of the three-phase load terminal voltage, substituting the first correction quantity into a three-phase symmetric relation discriminant to calculate, and if the value of the three-phase symmetric relation discriminant is not zero, enabling the capacitor to be in fault.
In the embodiment, the capacitor is used as a diagnosis environment when the capacitor is opened and exits the system, and the basic characteristics of the breaker when the breaker is opened are utilized: the three-phase terminal voltage waveform amplitude of the capacitor basically keeps a stable state, and the three-phase terminal voltage waveform amplitude and the neutral point potential always keep a three-phase symmetrical relation when the capacitor is not in fault, so that whether the capacitor is in fault or not is judged according to the three-phase load terminal voltage and the three-phase neutral point voltage of the capacitor based on the three-phase symmetrical relation when the capacitor is switched off and exits the system.
Furthermore, a person skilled in the art can also judge the initial phase according to the voltage wave amplitude of the three-phase load end of the capacitor; it should be noted that when the capacitor in the normal operating state exits the system, the capacitor needs to be opened and exited through the breaker connected to the capacitor. According to the circuit breaker separating brake principle, after the circuit breaker receives the separating brake signal, have certain looks sound contact at first to break in the three-phase, other two-phase later breaks off again, should break off at first the phase is first open phase, because the condenser under normal operating condition passes through the circuit breaker separating brake and withdraws from the system, produce the insulating of overvoltage threat condenser on first open phase, consequently can judge whether the condenser needs to be changed according to the first open phase of confirming, when avoiding putting into use again when insulating impaired condenser, switching-on surge and overvoltage can lead to the condenser to appear more serious insulating damage or even puncture and cause extensive trouble.
And 103, filtering the high-frequency harmonic component and the direct-current component of the first correction quantity to obtain a second correction quantity.
After a fault occurs, a high-frequency harmonic component which appears when the capacitor is switched off and a direct-current component which is stable finally after the capacitor is temporarily increased or decreased remain in the first correction quantity of the voltage of the three-phase load end; therefore, in the present embodiment, the high-frequency harmonic component and the dc component of the correction amount of the terminal voltage of the three-phase load are removed.
And 104, substituting the weighted mean value of the upper half cycle envelope curve of the second correction quantity and the weight value of the harmonic attenuation time constant into a voltage correction quantity calculation formula for calculation to obtain the voltage correction quantity of the three-phase load end, and setting the phase with the maximum correction quantity in the voltage correction quantity of the three-phase load end as a fault phase.
It should be noted that, for the weight of the harmonic attenuation time constant, a person skilled in the art can set the weight after experimental analysis, which is not limited herein; it can be understood that, in this embodiment, the weighted average of the upper half cycle envelope of the second correction is obtained, and the final correction at the three-phase load end of the capacitor is calculated according to the weighting value of the harmonic attenuation time constant obtained through experiments, where the phase with the largest amplitude among the three phases is the fault phase.
And 105, acquiring the current direction of each bridge arm capacitor in the fault phase, wherein when the current direction of each bridge arm capacitor is the inflow direction, the bridge arm capacitor is the fault bridge arm capacitor.
When a certain bridge arm of the capacitor fails, the discharging current of the failed capacitor only flows through the capacitor bridge arm connected in parallel with the failed capacitor, and the discharging current flows from the failed bridge arm to the failed bridge arm; therefore, after the fault phase is determined, the fault bridge arm capacitor is determined by obtaining the current direction of each bridge arm capacitor in the fault phase.
Therefore, a person skilled in the art can repair or replace the bridge arm capacitive element according to the bridge arm capacitance where the fault is located.
The application is used for the fault diagnosis method when the capacitor is switched out of the system, the capacitor is used as a diagnosis environment when the capacitor is switched off and exits the system, and the basic characteristics of the breaker when the breaker is switched off are utilized: the three-phase end voltage waveform amplitude of the capacitor basically keeps a stable state, and the three-phase symmetrical relation with the neutral point potential is always kept when the capacitor is not in fault, so that whether the capacitor is in fault or not is judged according to the three-phase load end voltage of the capacitor when the capacitor is switched off and exits the system; if the capacitor fails, removing the high-frequency harmonic component and the direct-current component of the correction quantity of the end voltage of the three-phase load, calculating the correction quantity of the end voltage of the three-phase load according to the average value of the envelope curves of the high-frequency harmonic component and the direct-current component, and setting the phase with the maximum correction quantity as a failure phase; and then judging the current direction of the determined fault phase capacitor, wherein the discharging current of the fault capacitor bridge arm only flows through the capacitor bridge arm connected in parallel with the fault capacitor bridge arm, and the direction of the discharging current flows from the non-fault bridge arm to the fault bridge arm, so that the specific fault bridge arm capacitor is determined according to the current direction, and whether the capacitor is in a fault state or not can be diagnosed and the specific fault position of the capacitor can be diagnosed under the condition that the internal fuse protection and the bridge difference current protection cannot normally act.
The first embodiment of the method for diagnosing the fault when the capacitor is switched out of the system is provided in the embodiment of the present application, and the second embodiment of the method for diagnosing the fault when the capacitor is switched out of the system is provided in the embodiment of the present application.
Referring to fig. 2, a second embodiment of a fault diagnosis method for a capacitor switching-out system according to the present application includes:
Step 201 is the same as step 101 of the embodiment, please refer to step 101 for description, which is not described herein.
And 202, subtracting the three-phase load terminal voltage from the three-phase neutral point voltage to obtain a first correction quantity of the three-phase load terminal voltage, substituting the first correction quantity into a three-phase symmetric relation discriminant to calculate, and if the value of the three-phase symmetric relation discriminant is not zero, enabling the capacitor to be in fault.
Step 202 is the same as step 102 of the embodiment, please refer to step 102 for description, which is not described herein.
The three-phase symmetric relation discriminant is as follows:
xA(n)+xB(n)+xC(n)＝0；
wherein the content of the first and second substances,
in the formula, xA(n)、xB(n)、xC(n) a-phase, B-phase, and C-phase correction amounts of a first correction amount of the three-phase load terminal voltage, respectively; u shapeA(n)、UB(n)、UC(n) three-phase load terminal voltages of A phase, B phase, C phase, and U phaseNAnd (n) is a three-phase neutral point voltage.
And step 203, acquiring the fault time of the capacitor according to the waveform diagram corresponding to the three-phase load terminal voltage.
It can be understood that, since the capacitor has the three-phase load terminal voltages corresponding to the capacitor at different times, the present embodiment can obtain the time when the capacitor fails according to the waveform diagram corresponding to the three-phase load terminal voltages.
And 204, taking the periodic average value of the high-frequency harmonic component as a third correction amount of the voltage of the three-phase load, and obtaining a second correction amount when the envelope average value of the third correction amount is within a preset threshold interval.
It can be understood that, for the high-frequency harmonic component of each period, the average value of the periods is obtained as a new terminal voltage correction quantity signal, and the brake-off harmonic is filtered out under the condition of not losing the harmonic component generated due to the fault. The present embodiment first uses the periodic average value of the high-frequency harmonic component as the third correction amount of the terminal voltage of the three-phase load.
And after the fault, the potential of the three-phase load terminal voltage of the capacitor can drop or rise to a certain degree, and the upper envelope mean value and the lower envelope mean value cannot be zero, so that a threshold interval is set, when the envelope mean value is positioned in the threshold interval, the envelope mean value is considered to be zero, and for the terminal voltage correction quantity for filtering out the high-frequency component, the upper envelope mean value and the lower envelope mean value are utilized to filter out the direct-current component to obtain a second correction quantity.
And step 205, substituting the weighted average of the envelope curve of the upper half cycle of the second correction and the weight of the harmonic attenuation time constant into a voltage correction calculation formula to calculate to obtain the correction of the end voltage of the three-phase load, and setting the phase with the maximum correction in the correction of the end voltage of the three-phase load as a fault phase.
Step 205 is the same as step 104 of the embodiment, please refer to step 104 for description, which is not described herein.
Wherein, the voltage correction quantity calculation formula is as follows:
in the formula, y3(n) is a correction amount of the terminal voltage of the three-phase load, kiIs the weight of the harmonic decay time constant, T is the harmonic decay time, e(+)And n voltage sampling points are the upper half-cycle envelope curve of the second correction, and i is a voltage sampling point.
And step 206, acquiring the current direction of each bridge arm capacitor in the fault phase, wherein when the current direction of the bridge arm capacitor is the inflow direction, the bridge arm capacitor is the fault bridge arm capacitor.
Step 206 is the same as step 105 in the embodiment, please refer to step 105 for description, which is not described herein.
In the second embodiment of the method for diagnosing a fault when a capacitor is switched out of a system according to the second embodiment of the present application, an embodiment of a device for diagnosing a fault when a capacitor is switched out of a system according to the second embodiment of the present application is provided below.
Referring to fig. 3, an embodiment of a fault diagnosis apparatus for a capacitor switching-out system according to the present application includes:
the obtaining unit 301 is configured to obtain a three-phase load terminal voltage and a three-phase neutral point voltage of the capacitor when the capacitor is opened and exits the system.
The first determining unit 302 is configured to subtract the three-phase load terminal voltage from the three-phase neutral point voltage to obtain a first correction amount of the three-phase load terminal voltage, substitute the first correction amount into the three-phase symmetric relation discriminant to calculate, and if a value of the three-phase symmetric relation discriminant is not zero, cause the capacitor to malfunction.
The calculating unit 303 is configured to filter the high-frequency harmonic component and the direct-current component of the first correction amount to obtain a second correction amount.
The second determination unit 304 is configured to substitute the weighted average of the upper half-cycle envelope of the second correction amount and the weight of the harmonic attenuation time constant into the voltage correction amount calculation formula to calculate, so as to obtain the three-phase load terminal voltage correction amount, and set the phase with the largest correction amount in the three-phase load terminal voltage correction amount as the fault phase.
The third determining unit 305 is configured to obtain a current direction of each bridge arm capacitor in the fault phase, and when the current direction of the bridge arm capacitor is an inflow direction, the bridge arm capacitor is the fault bridge arm capacitor.
Further, the present application also provides a fault diagnosis apparatus for capacitor switching-out system, the apparatus including a processor and a memory:
the memory is used for storing the program codes and transmitting the program codes to the processor;
the processor is used for executing any one of the above method embodiments for fault diagnosis when the capacitor is switched out of the system according to instructions in the program code.
Further, the present application also provides a computer-readable storage medium for storing program code for executing the fault diagnosis method in any one of the above method embodiments for the capacitor switching-out system.
It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
The terms "first," "second," "third," "fourth," and the like in the description of the present application and in the above-described drawings are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
It should be understood that in the present application, "at least one" means one or more, "a plurality" means two or more. "and/or" for describing an association relationship of associated objects, indicating that there may be three relationships, e.g., "a and/or B" may indicate: only A, only B and both A and B are present, wherein A and B may be singular or plural. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship. "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single item(s) or plural items. For example, at least one (one) of a, b, or c, may represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", wherein a, b, c may be single or plural.
In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other manners. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be substantially implemented or contributed to by the prior art, or all or part of the technical solution may be embodied in a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: a U disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
The above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.
Claims (10)
1. A fault diagnosis method for capacitor switching-out system, comprising:
s1, when the capacitor is opened and exits the system, acquiring the voltage of a three-phase load end and the voltage of a three-phase neutral point of the capacitor;
s2, subtracting the three-phase load end voltage from the three-phase neutral point voltage to obtain a first correction quantity of the three-phase load end voltage, substituting the first correction quantity into a three-phase symmetric relation discriminant to calculate, and if the value of the three-phase symmetric relation discriminant is not zero, the capacitor is in fault;
s3, filtering the high-frequency harmonic component and the direct-current component of the first correction quantity to obtain a second correction quantity;
s4, substituting the weighted mean value of the upper half cycle envelope curve of the second correction quantity and the weight value of the harmonic attenuation time constant into a voltage correction quantity calculation formula for calculation to obtain the three-phase load end voltage correction quantity, and setting the phase with the maximum correction quantity in the three-phase load end voltage correction quantity as a fault phase;
and S5, acquiring the current direction of each bridge arm capacitor in the fault phase, wherein the bridge arm capacitors are fault bridge arm capacitors when the current direction of the bridge arm capacitors is the inflow direction.
2. The method for diagnosing the fault in the capacitor switching-out system according to claim 1, further comprising, after step S2:
and acquiring the fault time of the capacitor according to the oscillogram corresponding to the three-phase load terminal voltage.
3. The method according to claim 1, wherein the filtering out a high-frequency harmonic component and a direct-current component of the first correction amount to obtain a second correction amount includes:
and taking the periodic average value of the high-frequency harmonic component as a third correction amount of the voltage of the three-phase load, and obtaining the second correction amount when the envelope average value of the third correction amount is within a preset threshold interval.
4. The method according to claim 1, wherein the three-phase symmetric relation criterion is:
xA(n)+xB(n)+xC(n)＝0；
wherein the content of the first and second substances,
in the formula, xA(n)、xB(n)、xC(n) a-phase, B-phase, and C-phase correction amounts of a first correction amount of the three-phase load terminal voltage, respectively; u shapeA(n)、UB(n)、UC(n) the voltages of the A phase, the B phase, the C phase and the U phase of the three-phase load terminal voltage are respectivelyNAnd (n) is a three-phase neutral point voltage.
5. The method according to claim 1, wherein the voltage correction amount calculation formula is:
in the formula，y3(n) is the correction amount of the three-phase load terminal voltage, kiIs the weight of the harmonic decay time constant, T is the harmonic decay time, e(+)The number of n voltage sampling points is the upper half cycle envelope curve of the second correction, and i is a voltage sampling point.
6. A fault diagnosis apparatus for capacitor cut-out system, comprising:
the device comprises an acquisition unit, a control unit and a control unit, wherein the acquisition unit is used for acquiring the voltage of a three-phase load end and the voltage of a three-phase neutral point of a capacitor when the capacitor is switched off and exits a system;
a first judging unit, configured to subtract the three-phase load terminal voltage from the three-phase neutral point voltage to obtain a first correction amount of the three-phase load terminal voltage, substitute the first correction amount into a three-phase symmetric relation discriminant to calculate, and if a value of the three-phase symmetric relation discriminant is not zero, cause the capacitor to malfunction;
the calculation unit is used for filtering out the high-frequency harmonic component and the direct-current component of the first correction quantity to obtain a second correction quantity;
the second judgment unit is used for substituting the weighted mean value of the envelope curve of the upper half cycle of the second correction quantity and the weight value of the harmonic attenuation time constant into a voltage correction quantity calculation formula for calculation to obtain the voltage correction quantity of the three-phase load end, and setting the phase with the maximum correction quantity in the voltage correction quantity of the three-phase load end as a fault phase;
and the third judging unit is used for acquiring the current direction of each bridge arm capacitor in the fault phase, and when the current direction of the bridge arm capacitor is the inflow direction, the bridge arm capacitor is the fault bridge arm capacitor.
7. The fault diagnosis device for capacitor cut-out system according to claim 6, further comprising: a fourth judgment unit;
and the time for the capacitor to break down is obtained according to the oscillogram corresponding to the three-phase load terminal voltage.
8. The device according to claim 6, wherein the computing unit is specifically configured to:
and taking the periodic average value of the high-frequency harmonic component as a third correction amount of the voltage of the three-phase load, and obtaining the second correction amount when the envelope average value of the third correction amount is within a preset threshold interval.
9. A fault diagnosis device for capacitor switching-out system, characterized in that the device comprises a processor and a memory:
the memory is used for storing program codes and transmitting the program codes to the processor;
the processor is used for executing the fault diagnosis method for the capacitor switching-out system according to any one of claims 1 to 5 according to the instructions in the program code.
10. A computer-readable storage medium characterized in that the computer-readable storage medium stores a program code for executing the fault diagnosis method for a capacitor cut-out system according to any one of claims 1 to 5.
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Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE815935A (en) * | 1973-06-07 | 1974-09-30 | PROCEDURE AND DEVICE FOR RECOGNIZING A DANGER IN A THREE-PHASE CURRENT NETWORK | |
| CN102621449A (en) * | 2012-03-16 | 2012-08-01 | 河南理工大学 | Single phase ground fault section locating method in small current grounding system |
| CN102788926A (en) * | 2012-07-04 | 2012-11-21 | 河南理工大学 | Single-phase ground fault section positioning method of small-current ground system |
| WO2015139587A1 (en) * | 2014-03-16 | 2015-09-24 | 田京涛 | Method for detecting ground fault of distribution network area and system for positioning ground fault area of distribution network |
| CN107037279A (en) * | 2016-10-31 | 2017-08-11 | 华北电力大学 | A kind of shunt capacitor monitoring system and its method |
| CN108469573A (en) * | 2018-03-21 | 2018-08-31 | 国网河南省电力公司漯河供电公司 | A kind of method that small current neutral grounding system utilizes error component phase selection |
| CN110045232A (en) * | 2019-05-16 | 2019-07-23 | 长沙理工大学 | A kind of system with non effectively earth ed neutral ground fault phase discrimination method |
| CN110703015A (en) * | 2019-09-27 | 2020-01-17 | 西安西电物联技术有限公司 | Capacitor monitoring method based on differential pressure |
| CN111308244A (en) * | 2020-03-07 | 2020-06-19 | 西南交通大学 | Direct current filter high-voltage capacitor fault positioning method based on current characteristics |
| CN111650514A (en) * | 2020-06-15 | 2020-09-11 | 珠海万力达电气自动化有限公司 | Multi-parameter joint diagnosis method for typical faults of asynchronous motor |
| CN111948467A (en) * | 2019-05-15 | 2020-11-17 | 南京南瑞继保电气有限公司 | Capacitor bank internal fault detection method and capacitor protection device |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8208235B2 (en) * | 2009-09-04 | 2012-06-26 | Lutron Electronics Co., Inc. | Method of detecting a fault condition of a load control device |
| JP5401250B2 (en) * | 2009-10-06 | 2014-01-29 | 日立オートモティブシステムズ株式会社 | Ground fault detection device |
-
2020
- 2020-12-03 CN CN202011398549.2A patent/CN112526405B/en active Active
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE815935A (en) * | 1973-06-07 | 1974-09-30 | PROCEDURE AND DEVICE FOR RECOGNIZING A DANGER IN A THREE-PHASE CURRENT NETWORK | |
| CN102621449A (en) * | 2012-03-16 | 2012-08-01 | 河南理工大学 | Single phase ground fault section locating method in small current grounding system |
| CN102788926A (en) * | 2012-07-04 | 2012-11-21 | 河南理工大学 | Single-phase ground fault section positioning method of small-current ground system |
| WO2015139587A1 (en) * | 2014-03-16 | 2015-09-24 | 田京涛 | Method for detecting ground fault of distribution network area and system for positioning ground fault area of distribution network |
| CN107037279A (en) * | 2016-10-31 | 2017-08-11 | 华北电力大学 | A kind of shunt capacitor monitoring system and its method |
| CN108469573A (en) * | 2018-03-21 | 2018-08-31 | 国网河南省电力公司漯河供电公司 | A kind of method that small current neutral grounding system utilizes error component phase selection |
| CN111948467A (en) * | 2019-05-15 | 2020-11-17 | 南京南瑞继保电气有限公司 | Capacitor bank internal fault detection method and capacitor protection device |
| CN110045232A (en) * | 2019-05-16 | 2019-07-23 | 长沙理工大学 | A kind of system with non effectively earth ed neutral ground fault phase discrimination method |
| CN110703015A (en) * | 2019-09-27 | 2020-01-17 | 西安西电物联技术有限公司 | Capacitor monitoring method based on differential pressure |
| CN111308244A (en) * | 2020-03-07 | 2020-06-19 | 西南交通大学 | Direct current filter high-voltage capacitor fault positioning method based on current characteristics |
| CN111650514A (en) * | 2020-06-15 | 2020-09-11 | 珠海万力达电气自动化有限公司 | Multi-parameter joint diagnosis method for typical faults of asynchronous motor |
Non-Patent Citations (2)
| Title |
|---|
| A method to diagnose the property of single-phase fault on high-voltage transmission lines;Chongfu Leng et al.;《2014 China International Conference on Electricity Distribution (CICED)》;20141222;第547-550页 * |
| 并联补偿电容器组的保护配置与故障仿真;李春雷;《中国优秀硕士学位论文全文数据库 工程科技Ⅱ辑》;20130115(第01期);C042-038 * |
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