CN112327235A - Current transformer fault detection method and device, electronic equipment and storage medium - Google Patents
Current transformer fault detection method and device, electronic equipment and storage medium Download PDFInfo
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- G01R35/02—Testing or calibrating of apparatus covered by the other groups of this subclass of auxiliary devices, e.g. of instrument transformers according to prescribed transformation ratio, phase angle, or wattage rating
Abstract
The application discloses a current transformer fault detection method and device, electronic equipment and a storage medium. The method comprises the following steps: under the condition that the power grid has no load, enabling the filter to inject reactive current into the power grid; acquiring sampling current sampled by the current transformer at the power grid side; and determining whether the current transformer has a fault according to the difference degree of the effective values of the reactive current and the sampling current and/or according to the difference degree of the phase sequence of the reactive current and the sampling current. The method realizes effective detection of the fault of the current transformer, avoids the problem that the normal compensation effect cannot be realized due to the fault of the current transformer when the filter works, and ensures the normal work of the filter. In addition, the method can be realized by using a filter working circuit without increasing extra cost, and the detection cost is saved.
Description
Technical Field
The application relates to the technical field of power electronics, in particular to a current transformer fault detection method and device, electronic equipment and a storage medium.
Background
When compensation filters such as Active Power Filters (APFs) work, an external Current Transformer (CT) is required to collect an external current signal for calculating a command current. If the external CT responsible for current sampling breaks down, the current sampling is abnormal, and further the APF cannot realize the normal compensation effect. Before the APF works, whether the external CT has faults or not is detected, and the method is of great importance for realizing the normal compensation effect of the APF. However, in the prior art, external CT fault detection is not performed, the filter directly performs grid-connected operation, and after a CT fault occurs, the filter may not normally operate and specific reasons cannot be known.
Disclosure of Invention
In view of the above, the present application is proposed to provide a current transformer fault detection method, apparatus, electronic device and storage medium that overcome or at least partially solve the above-mentioned problems.
According to an aspect of the present application, there is provided a current transformer fault detection method, the method including:
under the condition that the power grid has no load, enabling the filter to inject reactive current into the power grid;
acquiring sampling current sampled by the current transformer at the power grid side;
and determining whether the current transformer has a fault according to the difference degree of the effective values of the reactive current and the sampling current and/or according to the difference degree of the phase sequence of the reactive current and the sampling current.
Optionally, the determining whether the current transformer has a fault according to the difference between the effective values of the reactive current and the sampling current and/or according to the difference between the phase sequence of the reactive current and the sampling current comprises:
determining the effective value of each phase of reactive current and determining the effective value of each phase of sampling current;
determining the difference of effective values of each phase of reactive current and sampling current;
and when the accumulated times of the difference of the effective values of at least one phase being greater than or equal to the first threshold value reach a second threshold value, determining that the current transformer has a fault.
Optionally, the fault is specifically a sampling fault between the current transformer and the filter.
Optionally, the determining whether the current transformer has a fault according to the difference between the effective values of the reactive current and the sampling current and/or according to the difference between the phase sequence of the reactive current and the sampling current comprises:
and under the condition that the difference of the effective values of all the phases is smaller than a first threshold value, determining whether the current transformer has a fault according to the phase sequence difference degree of the reactive current and the sampling current.
Optionally, when the difference between the effective values of the phases is smaller than a first threshold, determining whether the current transformer has a fault according to the phase sequence difference degree of the sampling current includes:
respectively determining Q-axis components of the sampling current and the reactive current;
and determining the phase sequence difference degree of the sampling current and the reactive current according to the consistency of the symbol of the Q-axis component of the sampling current and the symbol of the Q-axis component of the reactive current.
Optionally, the determining the phase sequence difference degree of the sampled current and the reactive current according to the consistency of the sign of the Q-axis component of the sampled current and the sign of the Q-axis component of the reactive current comprises:
and when the times that the difference of the effective values of all the phases is smaller than the first threshold value reach a third threshold value, determining the phase sequence difference degree of the reactive current according to the times that the symbol of the Q-axis component of the sampling current is consistent with the symbol of the Q-axis component of the reactive current and the times that the symbol of the Q-axis component of the sampling current is inconsistent with the symbol of the Q-axis component of the reactive current at the moment.
Optionally, the method according to any of the preceding claims, wherein the fault is in particular a phase sequence error fault of a current transformer.
According to another aspect of the present application, there is provided a current transformer fault detection apparatus, the apparatus including:
the current injection unit is used for enabling the filter to inject reactive current into the power grid under the condition that the power grid has no load;
the sampling unit is used for acquiring sampling current sampled by the current transformer at the power grid side;
and the fault detection unit is used for determining whether the current transformer has faults or not according to the difference degree of the effective values of the reactive current and the sampling current and/or according to the difference degree of the phase sequence of the reactive current and the sampling current.
In accordance with yet another aspect of the present application, there is provided an electronic device including: a processor; and a memory arranged to store computer executable instructions that, when executed, cause the processor to perform a method as any one of the above.
According to a further aspect of the application, there is provided a computer readable storage medium, wherein the computer readable storage medium stores one or more programs which, when executed by a processor, implement a method as in any above.
According to the technical scheme, under the condition that the power grid is not loaded, the filter injects reactive current into the power grid, sampling current obtained by sampling the current transformer at the power grid side is obtained, whether the current transformer has faults or not can be determined according to the difference degree of the effective values of the reactive current and the sampling current and/or the difference degree of the phase sequence of the reactive current and the sampling current, effective detection of the faults of the current transformer is achieved, the situation that normal compensation effect cannot be achieved due to the faults of the current transformer when the filter works is avoided, and normal work of the filter is guaranteed. In addition, the fault detection method can be realized by using the working circuit of the filter, the additional cost is not required to be added, and the detection cost is saved.
The foregoing description is only an overview of the technical solutions of the present application, and the present application can be implemented according to the content of the description in order to make the technical means of the present application more clearly understood, and the following detailed description of the present application is given in order to make the above and other objects, features, and advantages of the present application more clearly understandable.
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Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the application. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:
fig. 1 shows a schematic diagram of the basic principle of operation of an active power filter according to an embodiment of the present application;
FIG. 2 illustrates a flow diagram of a current transformer fault detection method according to one embodiment of the present application;
FIG. 3 illustrates a flow diagram of another current transformer fault detection method according to one embodiment of the present application;
fig. 4 is a schematic structural diagram illustrating a current transformer fault detection apparatus according to an embodiment of the present application;
FIG. 5 shows a schematic structural diagram of an electronic device according to an embodiment of the present application;
FIG. 6 shows a schematic structural diagram of a computer-readable storage medium according to an embodiment of the present application.
Detailed Description
Exemplary embodiments of the present application will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
Fig. 1 shows a schematic diagram of the basic principle of operation of an active power filter according to an embodiment of the present application. As shown in FIG. 1, UsIs an alternating voltage isFor grid current, iLIs negativeCurrent carrying icTo compensate for the current, s1The load switch is adopted, and the CT is a current transformer and is connected in series outside the APF.
When the APF works, the load switch is closed, the nonlinear load generates harmonic wave and reactive current, the external CT collects the current of the power grid and the load current and is used for calculating the instruction current, the APF generates compensation current with the direction opposite to the direction of the instruction current and the same magnitude, and the reactive and harmonic current is compensated through a reactive and harmonic detection method, so that the power factor of the power grid side is improved, and the current distortion of the power grid side is reduced. If the external CT fails, current sampling is abnormal, and further the APF cannot realize normal compensation effect. The fault detection is carried out on the external CT before the APF works, so that the fault existing in the external CT can be found in time and repaired, the current sampling is ensured to be normal, and the APF realizes the normal compensation effect.
It should be noted that, this embodiment is only described by taking an APF as an example, and other filters that need to use an external CT to perform current sampling all have the same or similar problems, and the method of the present application may be used to perform fault detection on the external CT.
Fig. 2 shows a schematic flow chart of a current transformer fault detection method according to an embodiment of the present application. As shown in fig. 2, the method includes:
step S210, in the case of no load on the grid, causes the filter to inject reactive current into the grid.
In this embodiment, the CT fault detection is performed under the condition of no load on the power grid. At the moment, the external CT can be connected to the power grid side, the working mode of the filter is set to be the power grid side, the filter is manually set to inject reactive current into the power grid, a loop is formed between the filter and the external CT, whether the fault exists in the CT is detected through the current condition in the loop, the fault type is judged, the external CT is ensured to have no fault when the filter works normally, and the normal compensation function of the filter is not influenced.
Taking fig. 1 as an example, when the load switch is turned off, the load is not connected in the power grid, at this time, the external CT is connected to the power grid side, the APF is manually set to inject reactive current into the power grid, a loop is formed between the APF and the external CT, and by the current condition in the loop, whether the CT has a fault or not can be detected, and the fault type can be judged.
And step S220, obtaining sampling current sampled by the current transformer at the power grid side.
In this embodiment, since a loop is formed between the filter and the external CT, the reactive current injected into the power grid by the filter flows through the current transformer, and the current transformer samples the flowing reactive current to obtain the sampled current.
And step S230, determining whether the current transformer has faults or not according to the difference degree of the effective values of the reactive current and the sampling current and/or according to the difference degree of the phase sequence of the reactive current and the sampling current.
In this embodiment, the effective values of the reactive current and the sampling current are calculated, the difference between the effective value of the reactive current and the effective value of the sampling current is calculated, and whether a fault exists in the current transformer is determined according to the difference. And when the current transformer cannot be determined to have faults according to the difference degree, determining whether the current transformer has faults or not by combining the phase sequence difference degree of the sampling current. The two-stage criterion of the difference degree of the effective value and the difference degree of the phase sequence is used for fault detection, so that whether the current transformer has faults or not can be detected, the fault type can be judged, the troubleshooting time is saved, and the labor cost is reduced.
To sum up, according to the fault detection method for the current transformer of the embodiment, under the condition that the power grid has no load, the filter injects reactive current into the power grid to perform external CT fault detection, so that the external CT does not have faults when the filter works normally, and the problem that the filter cannot realize normal compensation effect due to the external CT faults is avoided. By acquiring sampling current obtained by sampling the current transformer at the power grid side and performing fault detection according to the two-stage criterion of the effective value difference degree and the phase sequence difference degree, whether the current transformer has a fault or not can be detected, the fault type can also be judged, the fault troubleshooting time is saved, and the labor cost is reduced.
In an embodiment of the application, the determining whether the current transformer has a fault according to the difference between the effective values of the reactive current and the sampling current and/or according to the difference between the phase sequences of the reactive current and the sampling current includes: determining the effective value of each phase of reactive current and determining the effective value of each phase of sampling current; determining the difference of effective values of each phase of reactive current and sampling current; and when the accumulated times of the difference of the effective values of at least one phase being greater than or equal to the first threshold value reach a second threshold value, determining that the current transformer has a fault.
In this embodiment, the reactive current may be a capacitive or inductive reactive current. Assuming that the reactive current and the sampling current are three-phase currents, the effective values of three-phase alternating current components corresponding to the reactive current are Iaref_rms、Ibref_rms、Icref_rmsThe effective values of the three-phase alternating current components corresponding to the sampling current are ISa_rms、ISb_rms、ISc_rmsCalculating the effective value I of each phase of the reactive current according to the formula (1-1)rms。
Where T is the cycle time of the alternating current, I(t)Is the ac current transient at time t.
And calculating the difference value of the reactive current component effective value of each phase and the sampling current component effective value according to the calculated three-phase alternating current component effective value corresponding to the reactive current and the three-phase alternating current component effective value corresponding to the sampling current, if the absolute value of the difference value of at least one phase current in the three-phase current is greater than or equal to a first threshold value, the counting of a corresponding counter is increased, and when the accumulated counting reaches a second threshold value, the current transformer is determined to have a fault. The first threshold value can be set as the percentage of the reactive current given by the filter according to the actual situation, and the second threshold value can also be set according to the actual situation.
If the absolute value of the difference value of the effective values of at least one phase of current in the three-phase current is larger than or equal to the first threshold value, namely the current transformer is judged to have a fault, the judgment is likely to be wrong. In the embodiment, the condition that the absolute value of the difference value of at least one phase current effective value in the three-phase current is greater than or equal to the first threshold value is counted, and the threshold value is set, so that the current transformer is determined to have a fault only when the number of times of occurrence of the condition that the absolute value of the difference value of at least one phase current effective value in the three-phase current is greater than or equal to the first threshold value reaches the preset threshold value, the judgment error can be effectively avoided, and the accuracy of the judgment result is ensured.
Fig. 3 shows a schematic flow diagram of another current transformer fault detection method according to an embodiment of the present application. As shown in fig. 3, in the present embodiment, the first threshold is preset to be 30% of the given reactive current, the second threshold is 100, and the counter Timer3 is used for counting. Respectively calculating the difference value of the three-phase alternating component effective value of the reactive current and the sampling current, namely the a-phase current effective value Iaref_rmsAnd ISa_rmsDifference value of (I)aEffective value of b-phase current Ibref_rmsAnd ISb_rmsDifference value of (I)bEffective value of c-phase current Icref_rmsAnd ISc_rmsDifference value of (I)cIf I isa、Ib、IcIf the absolute value of at least one of the absolute values of (a) is greater than or equal to 30% of the reactive current, the counter Timer3 counts up by 1; if Ia、Ib、IcIs less than 30% of the reactive current, the counter Timer3 does not count up, and the counter Timer2 counts up. I.e. if IaIs greater than 30% of the reactive current, IbAnd IcIf the absolute values of the current values are less than 30% of the reactive current, the Timer3 counts and adds 1; if IaAnd IbAre all greater than 30% of the reactive current, IcIs less than 30% of the reactive current, the Timer3 count is also incremented by 1; if Ia、Ib、IcIs less than 30% of the reactive current, the Timer3 count is not incremented and the counter Timer2 count is incremented. When the accumulated count of the Timer3 reaches 100, it is determined that a fault exists in the current transformer, and the fault is specifically a sampling fault, such as a disconnection of a connection, a short circuit of a connection, and the like, between the current transformer and the filter.
In an embodiment of the application, the determining whether the current transformer has a fault according to the difference between the effective values of the reactive current and the sampling current and/or according to the difference between the phase sequences of the reactive current and the sampling current includes: and under the condition that the difference of the effective values of all the phases is smaller than a first threshold value, determining whether the current transformer has faults or not according to the phase sequence difference degree of the reactive current and the sampling current.
In this embodiment, when the difference between the effective values of the phases is smaller than the first threshold, it is indicated that the current transformer has no sampling fault, but whether the current transformer has other faults cannot be determined. In this case, whether other faults exist in the current transformer, such as a phase sequence error fault, is determined by judging the phase sequence difference degree of the reactive current and the sampling current.
In an embodiment of the application, in the method, when the difference between the effective values of the phases is smaller than the first threshold, determining whether the current transformer has a fault according to the phase sequence difference degree of the sampling current includes: respectively determining Q-axis components of the sampling current and the reactive current; and determining the phase sequence difference degree of the sampling current and the reactive current according to the consistency of the symbol of the Q-axis component of the sampling current and the symbol of the Q-axis component of the reactive current.
In this embodiment, the instantaneous reactive theory is adopted to perform coordinate transformation on the reactive current given by the filter to obtain the Q-axis component I thereofq. Performing abc-dq coordinate transformation on the sampling current by adopting a synchronous rotation coordinate transformation harmonic detection method (dq method) to obtain a Q-axis component I of the sampling currentSqThe abc-dq coordinate transformation method specifically comprises the following steps:
firstly, Clark conversion is carried out by adopting an equation (1-2), three-phase currents are converted into an alpha beta coordinate system from an a coordinate system, a b coordinate system and a c coordinate system, and then park conversion is carried out by adopting an equation (1-3), and the alpha beta coordinate system is converted into a dq rotation coordinate system.
Where ω t is the grid voltage phase.
After the Q-axis component of the reactive current and the sampling current is obtained, whether the sign of the Q-axis component of the sampling current is the same as that of the Q-axis component of the reactive current in positive and negative is judged, and the phase sequence difference degree of the sampling current and the reactive current is determined according to the consistency condition of the sign of the Q-axis component of the sampling current and the sign of the Q-axis component of the reactive current.
In an embodiment of the application, the determining the phase sequence difference degree of the sampled current and the reactive current according to the consistency of the sign of the Q-axis component of the sampled current and the sign of the Q-axis component of the reactive current includes: and when the times that the difference of the effective values of all the phases is smaller than the first threshold value reach a third threshold value, determining the phase sequence difference degree of the reactive current according to the times that the symbol of the Q-axis component of the sampling current is consistent with the symbol of the Q-axis component of the reactive current and the times that the symbol of the Q-axis component of the sampling current is inconsistent with the symbol of the Q-axis component of the reactive current at the moment.
In this embodiment, when the difference between the effective values of the phases is smaller than the first threshold, the corresponding counter counts up, and simultaneously, whether the sign of the Q-axis component of the sampled current is consistent with the sign of the Q-axis component of the reactive current is determined, if the signs are consistent, the corresponding counter counts up, and if the signs are not consistent, the corresponding counter counts down. And when the accumulated times that the difference of the effective values of all the phases is smaller than the first threshold value reach a third threshold value, and the times that the symbol of the Q-axis component of the sampling current is consistent with the symbol of the Q-axis component of the reactive current reach a fourth threshold value, determining that the phase sequence of the current transformer is correct and the current transformer has no fault. When the accumulated times that the difference of the effective values of all the phases is smaller than the first threshold value reach a third threshold value, and the times that the symbols of the Q-axis component of the sampling current are consistent with the symbols of the Q-axis component of the reactive current do not reach a fourth threshold value, it is determined that the phase sequence of the current transformer is wrong, and the current transformer has a fault, and the fault is specifically a fault of the phase sequence of the current transformer, such as a phase sequence connection fault and the like.
In the embodiment, the situation that the difference of the effective values of all phases is smaller than the first threshold value and the situation that the symbol of the Q-axis component of the sampling current is consistent with the symbol of the Q-axis component of the reactive current are counted respectively, corresponding threshold values are set, the difference degree of the phase sequence of the sampling current and the reactive current is reflected according to the counting situation, and when the difference degree reaches the preset threshold value, it is determined that the phase sequence of the current transformer is wrong, and the current transformer has faults. The current transformer fault detection method has the advantages that fault detection can be carried out on the current transformer, judgment errors can be effectively avoided, and the accuracy of judgment results is guaranteed. As shown in fig. 3, the counter Timer1 is used to count the number of phases with effective value differences smaller than the first threshold, and the counter Timer2 is used to count the number of phases with the Q-axis component sign of the sampling current consistent with the Q-axis component sign of the reactive current. The first threshold value is set to 30% of the given reactive current, the third threshold value is 100 and the fourth threshold value is 90. When the difference in the effective values of the phases is less than the first threshold, the counter Timer1 is incremented. And under the condition, judging whether the symbol of the Q-axis component of the sampling current is consistent with the symbol of the Q-axis component of the reactive current, if so, increasing the count of the counter Timer2, and if not, decreasing the count of the counter Timer 2. When the Timer1 count accumulation reaches 100, if the Timer2 count accumulation is greater than or equal to 90, the current transformer phase sequence is determined to be correct and no fault exists. If the count accumulation of the Timer2 is less than 90 when the Timer1 count accumulation reaches 100, it is determined that a phase sequence error fault exists in the current transformer.
It should be noted that the specific values of the third threshold and the fourth threshold are only specific examples in one embodiment, and a user may set specific values of the third threshold and the fourth threshold according to actual situations.
Fig. 4 shows a schematic structural diagram of a current transformer fault detection apparatus according to an embodiment of the present application. As shown in fig. 4, the current transformer fault detection apparatus 400 includes:
a current injection unit 410, configured to enable the filter to inject a reactive current into the power grid when the power grid is not loaded;
the sampling unit 420 is configured to obtain a sampling current sampled by the current transformer at a power grid side;
and a fault detection unit 430, configured to determine whether a fault exists in the current transformer according to the difference between the effective values of the reactive current and the sampling current and/or according to the difference between the phase sequences of the reactive current and the sampling current.
In an embodiment of the present application, in the above apparatus, the fault detection unit 430 is specifically configured to determine an effective value of a reactive current of each phase, and determine an effective value of a sampled current of each phase; determining the difference of effective values of each phase of reactive current and sampling current; and when the accumulated times of the difference of the effective values of at least one phase being greater than or equal to the first threshold value reach a second threshold value, determining that the current transformer has a fault, wherein the fault is a sampling fault between the current transformer and the filter.
In an embodiment of the present application, in the above apparatus, the fault detection unit 430 is specifically configured to determine whether the current transformer has a fault according to a phase sequence difference degree between the reactive current and the sampling current when the difference between the effective values of the phases is smaller than the first threshold. The fault is specifically a phase sequence error fault of the current transformer.
In one embodiment of the present application, in the above apparatus, the fault detection unit 430 includes a phase sequence detection unit for determining Q-axis components of the sampled current and the reactive current, respectively; and determining the phase sequence difference degree of the sampling current and the reactive current according to the consistency of the symbol of the Q-axis component of the sampling current and the symbol of the Q-axis component of the reactive current.
In an embodiment of the application, in the above apparatus, the phase sequence detecting unit is specifically configured to, when the number of times that the difference in the effective values of the phases is smaller than the first threshold reaches a third threshold, determine the degree of difference in the phase sequence of the reactive current according to the number of times that the sign of the Q-axis component of the sampled current coincides with the sign of the Q-axis component of the reactive current at that time and the number of times that the sign of the Q-axis component of the sampled current does not coincide with the sign of the Q-axis component of the reactive current.
It should be noted that, for the specific implementation of each apparatus embodiment, reference may be made to the specific implementation of the corresponding method embodiment, which is not described herein again.
To sum up, the technical scheme of this application makes the wave filter inject reactive current to the electric wire netting through under the unloaded condition of electric wire netting, carries out external CT fault detection, guarantees that the external CT of wave filter normal during operation does not have the trouble, avoids leading to the unable normal compensation effect of realizing of wave filter because of external CT trouble. By acquiring the sampling current sampled by the current transformer at the power grid side and performing fault detection according to the two-stage criterion of the difference degree of the effective value and the difference degree of the phase sequence of the sampling current and the reactive current, whether the current transformer has a fault or not can be detected, the fault type can be judged, the fault type is displayed in monitoring, the fault troubleshooting time can be saved, and the labor cost is reduced. And when fault detection is carried out according to the two-stage criterion of the difference degree of the effective value and the difference degree of the phase sequence of the sampling current and the reactive current, the corresponding situation is counted and the corresponding threshold value is set, so that misjudgment can be effectively avoided, the accuracy of the detection result is ensured, and the waste of time cost and labor cost caused by misjudgment is avoided.
It should be noted that:
the algorithms and displays presented herein are not inherently related to any particular computer, virtual machine, or other apparatus. Various general purpose devices may be used with the teachings herein. The required structure for constructing such a device will be apparent from the description above. In addition, this application is not directed to any particular programming language. It will be appreciated that a variety of programming languages may be used to implement the teachings of the present application as described herein, and any descriptions of specific languages are provided above to disclose the best modes of the present application.
In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the application may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.
Similarly, it should be appreciated that in the foregoing description of exemplary embodiments of the application, various features of the application are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the application and aiding in the understanding of one or more of the various inventive aspects. However, the disclosed method should not be interpreted as reflecting an intention that: this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this application.
Those skilled in the art will appreciate that the modules in the device in an embodiment may be adaptively changed and disposed in one or more devices different from the embodiment. The modules or units or components of the embodiments may be combined into one module or unit or component, and furthermore they may be divided into a plurality of sub-modules or sub-units or sub-components. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and all of the processes or elements of any method or apparatus so disclosed, may be combined in any combination, except combinations where at least some of such features and/or processes or elements are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.
Furthermore, those skilled in the art will appreciate that while some embodiments described herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the application and form different embodiments. For example, in the following claims, any of the claimed embodiments may be used in any combination.
The various component embodiments of the present application may be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. Those skilled in the art will appreciate that a microprocessor or Digital Signal Processor (DSP) may be used in practice to implement some or all of the functions of some or all of the components in a current transformer fault detection apparatus according to embodiments of the present application. The present application may also be embodied as apparatus or device programs (e.g., computer programs and computer program products) for performing a portion or all of the methods described herein. Such programs implementing the present application may be stored on a computer readable medium or may be in the form of one or more signals. Such a signal may be downloaded from an internet website or provided on a carrier signal or in any other form.
For example, fig. 5 shows a schematic structural diagram of an electronic device according to an embodiment of the present application. The electronic device 500 comprises a processor 510 and a memory 520 arranged to store computer executable instructions (computer readable program code). The memory 520 may be an electronic memory such as a flash memory, an EEPROM (electrically erasable programmable read only memory), an EPROM, a hard disk, or a ROM. The memory 520 has a storage space 530 storing computer readable program code 531 for performing any of the method steps in the above described method. For example, the storage space 530 for storing the computer readable program code may include respective computer readable program codes 531 for respectively implementing various steps in the above method. The computer readable program code 531 may be read from or written to one or more computer program products. These computer program products comprise a program code carrier such as a hard disk, a Compact Disc (CD), a memory card or a floppy disk. Such a computer program product is typically a computer readable storage medium such as described in fig. 6. FIG. 6 shows a schematic diagram of a computer-readable storage medium according to an embodiment of the present application. The computer readable storage medium 600 has stored thereon a computer readable program code 531 for performing the steps of the method according to the application, readable by the processor 510 of the electronic device 500, which computer readable program code 531, when executed by the electronic device 500, causes the electronic device 500 to perform the steps of the method described above, in particular the computer readable program code 531 stored on the computer readable storage medium may perform the method shown in any of the embodiments described above. The computer readable program code 531 may be compressed in a suitable form.
It should be noted that the above-mentioned embodiments illustrate rather than limit the application, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The application may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The usage of the words first, second and third, etcetera do not indicate any ordering. These words may be interpreted as names.
Claims (10)
1. A method of current transformer fault detection, the method comprising:
under the condition that the power grid has no load, enabling the filter to inject reactive current into the power grid;
acquiring sampling current sampled by the current transformer at the power grid side;
and determining whether the current transformer has a fault according to the difference degree of the effective values of the reactive current and the sampling current and/or according to the difference degree of the phase sequence of the reactive current and the sampling current.
2. The method of claim 1, wherein the determining whether the current transformer has a fault according to the difference in the effective values of the reactive current and the sampled current and/or according to the difference in the phase sequence of the reactive current and the sampled current comprises:
determining the effective value of each phase of reactive current and determining the effective value of each phase of sampling current;
determining the difference of effective values of each phase of reactive current and sampling current;
and when the accumulated times of the difference of the effective values of at least one phase being greater than or equal to the first threshold value reach a second threshold value, determining that the current transformer has a fault.
3. Method according to claim 2, characterized in that the fault is in particular a sampling fault between the current transformer and the filter.
4. The method of claim 3, wherein the determining whether the current transformer has a fault according to the difference between the effective values of the reactive current and the sampled current and/or according to the difference between the phase sequence of the reactive current and the sampled current comprises:
and under the condition that the difference of the effective values of all the phases is smaller than a first threshold value, determining whether the current transformer has a fault according to the phase sequence difference degree of the reactive current and the sampling current.
5. The method of claim 4, wherein the determining whether the current transformer has a fault according to the phase sequence difference degree of the sampling current when the effective value difference of each phase is smaller than the first threshold comprises:
respectively determining Q-axis components of the sampling current and the reactive current;
and determining the phase sequence difference degree of the sampling current and the reactive current according to the consistency of the symbol of the Q-axis component of the sampling current and the symbol of the Q-axis component of the reactive current.
6. The method of claim 5, wherein the determining the degree of phase-sequence disparity of the sampled current and the reactive current based on the coincidence of the sign of the Q-axis component of the sampled current with the sign of the Q-axis component of the reactive current comprises:
and when the times that the difference of the effective values of all the phases is smaller than the first threshold value reach a third threshold value, determining the phase sequence difference degree of the reactive current according to the times that the symbol of the Q-axis component of the sampling current is consistent with the symbol of the Q-axis component of the reactive current and the times that the symbol of the Q-axis component of the sampling current is inconsistent with the symbol of the Q-axis component of the reactive current at the moment.
7. Method according to any of claims 4-6, characterized in that the fault is in particular a phase sequence error fault of a current transformer.
8. A current transformer fault detection apparatus, the apparatus comprising:
the current injection unit is used for enabling the filter to inject reactive current into the power grid under the condition that the power grid has no load;
the sampling unit is used for acquiring sampling current sampled by the current transformer at the power grid side;
and the fault detection unit is used for determining whether the current transformer has faults or not according to the difference degree of the effective values of the reactive current and the sampling current and/or according to the difference degree of the phase sequence of the reactive current and the sampling current.
9. An electronic device, comprising: a processor; and a memory arranged to store computer-executable instructions that, when executed, cause the processor to perform the method of any one of claims 1-7.
10. A computer readable storage medium, characterized in that the computer readable storage medium stores one or more programs which, when executed by a processor, implement the method of any of claims 1-7.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117075027A (en) * | 2023-10-16 | 2023-11-17 | 江苏纳通能源技术有限公司 | CT transformer fault identification method and identification system thereof |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1414396A (en) * | 2002-05-21 | 2003-04-30 | 重庆龙源科技产业发展有限公司 | Method and device for real time on line detection of metering current mulual inductor malfunction |
| CN2579079Y (en) * | 2001-07-19 | 2003-10-08 | 松下电器产业株式会社 | Motor driver of washing machine |
| CN101017188A (en) * | 2007-02-12 | 2007-08-15 | 烟台东方电子信息产业股份有限公司 | Detecting method for line breaking and circuit shorting of CT |
| CN101046484A (en) * | 2007-04-23 | 2007-10-03 | 国电南京自动化股份有限公司 | Current transformer saturation detecting technology based on phase comparing method |
| CN102087347A (en) * | 2009-12-08 | 2011-06-08 | 张建 | Charged test method for current transformer and application thereof |
| CN104267368A (en) * | 2014-10-14 | 2015-01-07 | 国家电网公司 | Fault monitoring method for secondary circuit of metering current transformer |
| CN104865481A (en) * | 2015-06-18 | 2015-08-26 | 烟台东方威思顿电气股份有限公司 | Detecting method for load management to terminal external CT secondary side loop states |
| CN106226612A (en) * | 2016-07-04 | 2016-12-14 | 国家电网公司 | Secondary wiring of current mutual inductor method for diagnosing faults based on pincerlike phase meter |
| CN106451466A (en) * | 2016-11-01 | 2017-02-22 | 辽宁工程技术大学 | Grid power quality control system and method based on unified power quality conditioner |
| CN107861086A (en) * | 2017-12-27 | 2018-03-30 | 北京东方计量测试研究所 | A kind of in-orbit calibration method of current sensor applied to space and device |
-
2020
- 2020-09-23 CN CN202011008640.9A patent/CN112327235A/en active Pending
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2579079Y (en) * | 2001-07-19 | 2003-10-08 | 松下电器产业株式会社 | Motor driver of washing machine |
| CN1414396A (en) * | 2002-05-21 | 2003-04-30 | 重庆龙源科技产业发展有限公司 | Method and device for real time on line detection of metering current mulual inductor malfunction |
| CN101017188A (en) * | 2007-02-12 | 2007-08-15 | 烟台东方电子信息产业股份有限公司 | Detecting method for line breaking and circuit shorting of CT |
| CN101046484A (en) * | 2007-04-23 | 2007-10-03 | 国电南京自动化股份有限公司 | Current transformer saturation detecting technology based on phase comparing method |
| CN102087347A (en) * | 2009-12-08 | 2011-06-08 | 张建 | Charged test method for current transformer and application thereof |
| CN104267368A (en) * | 2014-10-14 | 2015-01-07 | 国家电网公司 | Fault monitoring method for secondary circuit of metering current transformer |
| CN104865481A (en) * | 2015-06-18 | 2015-08-26 | 烟台东方威思顿电气股份有限公司 | Detecting method for load management to terminal external CT secondary side loop states |
| CN106226612A (en) * | 2016-07-04 | 2016-12-14 | 国家电网公司 | Secondary wiring of current mutual inductor method for diagnosing faults based on pincerlike phase meter |
| CN106451466A (en) * | 2016-11-01 | 2017-02-22 | 辽宁工程技术大学 | Grid power quality control system and method based on unified power quality conditioner |
| CN107861086A (en) * | 2017-12-27 | 2018-03-30 | 北京东方计量测试研究所 | A kind of in-orbit calibration method of current sensor applied to space and device |
Non-Patent Citations (3)
| Title |
|---|
| 侯战斌;郭飞;闻志国;李岩;李胜芳;: "电流互感器二次侧接入状态在线监测装置技术", 科技和产业, no. 04, 25 April 2020 (2020-04-25) * |
| 张伟;李根富;张枫;: "IGBT整流器功率因数控制方法及CT损坏对整流器的影响", 变频器世界, no. 05, 15 May 2008 (2008-05-15) * |
| 王舒萍;刘变变;郭佳欢;: "配电网无功补偿相关研究", 科技经济导刊, no. 08, 15 March 2018 (2018-03-15) * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117075027A (en) * | 2023-10-16 | 2023-11-17 | 江苏纳通能源技术有限公司 | CT transformer fault identification method and identification system thereof |
| CN117075027B (en) * | 2023-10-16 | 2024-01-26 | 江苏纳通能源技术有限公司 | CT transformer fault identification method and identification system thereof |
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