CN113555885A - Method and device for determining amplitude limiting coefficient of three-phase unbalanced current and storage medium - Google Patents

Method and device for determining amplitude limiting coefficient of three-phase unbalanced current and storage medium Download PDF

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CN113555885A
CN113555885A CN202110856550.3A CN202110856550A CN113555885A CN 113555885 A CN113555885 A CN 113555885A CN 202110856550 A CN202110856550 A CN 202110856550A CN 113555885 A CN113555885 A CN 113555885A
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current
phase
current data
phase current
unbalanced
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张洪涛
杨宗丰
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Langfang In Power Electric Co ltd
BEIJING IN-POWER ELECTRIC CO LTD
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Langfang In Power Electric Co ltd
BEIJING IN-POWER ELECTRIC CO LTD
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/26—Arrangements for eliminating or reducing asymmetry in polyphase networks
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/04—Measuring peak values or amplitude or envelope of ac or of pulses
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
    • H02J2203/10—Power transmission or distribution systems management focussing at grid-level, e.g. load flow analysis, node profile computation, meshed network optimisation, active network management or spinning reserve management
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/50—Arrangements for eliminating or reducing asymmetry in polyphase networks

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Supply And Distribution Of Alternating Current (AREA)
  • Emergency Protection Circuit Devices (AREA)

Abstract

The application provides a method and a device for determining a three-phase unbalanced current amplitude limiting coefficient and a storage medium, which are used for correcting three-phase current data acquired at the acquisition time of each sampling point in a sampling control period through current load equipment to obtain actual current data of the sampling point; and performing coordinate transformation and low-pass filtering processing on the actual current data, extracting each unbalanced current component data from the actual current data, calculating to obtain the current amplitude of each unbalanced current of each phase current in the three-phase current passing through the current load equipment at the acquisition time of the sampling control period, and determining a target amplitude limiting coefficient for limiting the three-phase current passing through the current load equipment in the sampling control period by comparing the maximum current amplitude with the rated current value of the reactive compensation equipment. Therefore, given adjustment of three-phase unbalanced current can be achieved, the problem of frequent faults caused by overlarge unbalanced current can be avoided, and potential safety hazards of a client side can be reduced.

Description

Method and device for determining amplitude limiting coefficient of three-phase unbalanced current and storage medium
Technical Field
The present disclosure relates to the field of current limiting technologies, and in particular, to a method and an apparatus for determining a three-phase unbalanced current limiting coefficient, and a storage medium.
Background
In actual life, when three-phase load power in a used power grid is different or a large number of single-phase loads exist, imbalance of three-phase current in the power grid is easily caused, and then, a large zero-sequence current flows through a zero line, and the zero-sequence current on the zero line can often reach three times of the zero-sequence current on a phase line under the condition. In the use process of a power grid, if the current flowing through the zero line is too large, the zero line is heated, the insulating layer is aged, and the line loss is increased; if the transmission line is too long, a large zero-sequence voltage drop is generated on the zero line, so that the problem of unbalanced three-phase voltage of the user side occurs, the serious problem of electric energy quality and the potential safety hazard of the user side are caused, and therefore, how to reasonably adjust the three-phase current in the power grid becomes a problem to be solved urgently.
Disclosure of Invention
In view of this, an object of the present application is to provide a method, an apparatus, and a storage medium for determining a three-phase unbalanced current amplitude limiting coefficient, which can accurately determine a target amplitude limiting coefficient for adjusting a three-phase current, so as to achieve a given adjustment of the three-phase current, avoid a frequent fault problem caused by an excessive unbalanced current, and help to reduce potential safety hazards of a client.
The embodiment of the application provides a method for determining a three-phase unbalanced current amplitude limiting coefficient, which comprises the following steps:
acquiring three-phase current data of the overcurrent load equipment acquired in each sampling control period;
correcting the three-phase current data to obtain actual current data corresponding to the three-phase current data;
carrying out coordinate transformation and low-pass filtering processing on the actual current data, and calculating to obtain the current amplitude of the unbalanced current of each phase current in the three-phase current passing through the current load equipment at the acquisition time of the sampling control period;
and comparing the maximum current amplitude in the three-phase current with the rated current value of the reactive compensation equipment, and calculating to obtain an amplitude limiting coefficient for limiting the unbalanced current of each phase current in the three-phase current passing through the current load equipment in the sampling control period.
In a possible embodiment, the performing the correction processing on the three-phase current data to obtain actual current data corresponding to the three-phase current data includes:
acquiring a correction coefficient of a sampling channel used for acquiring the three-phase current data;
checking whether the three-phase current data are correct or not;
if the three-phase current data are correct, filtering zero drift data in the three-phase current data to obtain the three-phase current data with the zero drift filtered;
and calculating actual current data corresponding to the three-phase current data based on the three-phase current data subjected to zero drift filtering and the correction coefficient.
In a possible embodiment, the performing coordinate transformation and low-pass filtering processing on the actual current data to calculate a current amplitude of an unbalanced current of each phase current in three-phase currents flowing through a load device at a collection time of the sampling control period includes:
carrying out coordinate transformation and low-pass filtering processing on the actual current data, and extracting a plurality of unbalanced components from the actual current data;
and calculating the current amplitude of the unbalanced current of each phase current in the three-phase current passing through the load equipment at the acquisition time of the sampling control period by using the plurality of unbalanced components.
In a possible embodiment, the unbalance components comprise the active and reactive components of the negative sequence current and the active and reactive components of the zero sequence current.
In a possible embodiment, after the calculating obtains the clipping coefficient for limiting the unbalanced current of each phase current in the three-phase currents flowing through the load device in the sampling control period, the determining method further includes:
correcting the three-phase current data acquired in the sampling control period by using the amplitude limiting coefficient, and calculating to obtain a plurality of unbalanced components to obtain a plurality of corrected unbalanced components;
and superposing the corrected unbalanced components according to the original phase of each unbalanced component in each phase of current respectively to obtain corrected three-phase current data corresponding to the sampling control period.
In one possible embodiment, the coordinate transformation and low-pass filtering process performed on the actual current data to extract a plurality of imbalance components from the actual current data includes:
respectively carrying out negative sequence rotation coordinate transformation and zero sequence rotation coordinate transformation on the actual current data, and converting the actual current data from a static coordinate system to a negative sequence rotation coordinate system and a zero sequence rotation coordinate system;
respectively converting actual current data under the negative sequence rotating coordinate system and the zero sequence rotating coordinate system from a three-phase coordinate system to a two-phase coordinate system to respectively obtain negative sequence current data and zero sequence current data under the two-phase coordinate system;
and respectively carrying out low-pass filtering processing on the negative sequence current data and the zero sequence current data to obtain a plurality of unbalanced components.
The embodiment of the application further provides a device for determining the three-phase current amplitude limiting coefficient, wherein the device for determining the three-phase current amplitude limiting coefficient comprises:
the data acquisition module is used for acquiring the three-phase current data of the overcurrent load equipment acquired in each sampling control period;
the correction processing module is used for correcting the three-phase current data to obtain actual current data corresponding to the three-phase current data;
the amplitude calculation module is used for carrying out coordinate transformation and low-pass filtering processing on the actual current data and calculating to obtain the current amplitude of the unbalanced current of each phase current in the three-phase current passing through the current load equipment at the acquisition time of the sampling control period;
and the coefficient calculation module is used for comparing the maximum current amplitude in the three-phase current with the rated current value of the reactive compensation equipment, and calculating to obtain the amplitude limiting coefficient for limiting the unbalanced current of each phase in the three-phase current passing through the current load equipment in the sampling control period.
In a possible implementation manner, when the correction processing module is configured to perform correction processing on the three-phase current data to obtain actual current data corresponding to the three-phase current data, the correction processing module is configured to:
acquiring a correction coefficient of a sampling channel used for acquiring the three-phase current data;
checking whether the three-phase current data are correct or not;
if the three-phase current data are correct, filtering zero drift data in the three-phase current data to obtain the three-phase current data with the zero drift filtered;
and calculating actual current data corresponding to the three-phase current data based on the three-phase current data subjected to zero drift filtering and the correction coefficient.
In a possible embodiment, when the amplitude calculation module is configured to perform coordinate transformation and low-pass filtering on the actual current data to calculate a current amplitude of an unbalanced current of each phase current in three-phase currents flowing through a load device at a collection time of the sampling control period, the amplitude calculation module is configured to:
carrying out coordinate transformation and low-pass filtering processing on the actual current data, and extracting a plurality of unbalanced components from the actual current data;
and calculating the current amplitude of the unbalanced current of each phase current in the three-phase current passing through the load equipment at the acquisition time of the sampling control period by using the plurality of unbalanced components.
In a possible embodiment, the unbalance components comprise the active and reactive components of the negative sequence current and the active and reactive components of the zero sequence current.
In a possible implementation, the determining apparatus further includes a current correction module, and the current correction module is configured to:
correcting the three-phase current data acquired in the sampling control period by using the amplitude limiting coefficient, and calculating to obtain a plurality of unbalanced components to obtain a plurality of corrected unbalanced components;
and superposing the corrected unbalanced components according to the original phase of each unbalanced component in each phase of current respectively to obtain corrected three-phase current data corresponding to the sampling control period.
In a possible embodiment, when the amplitude calculation module is configured to perform coordinate transformation and low-pass filtering on the actual current data to extract a plurality of imbalance components from the actual current data, the amplitude calculation module is configured to:
respectively carrying out negative sequence rotation coordinate transformation and zero sequence rotation coordinate transformation on the actual current data, and converting the actual current data from a static coordinate system to a negative sequence rotation coordinate system and a zero sequence rotation coordinate system;
respectively converting actual current data under the negative sequence rotating coordinate system and the zero sequence rotating coordinate system from a three-phase coordinate system to a two-phase coordinate system to respectively obtain negative sequence current data and zero sequence current data under the two-phase coordinate system;
and respectively carrying out low-pass filtering processing on the negative sequence current data and the zero sequence current data to obtain a plurality of unbalanced components.
An embodiment of the present application further provides an electronic device, including: a processor, a memory and a bus, the memory storing machine readable instructions executable by the processor, the processor and the memory communicating via the bus when the electronic device is operating, the machine readable instructions when executed by the processor performing the steps of the method of determining a three-phase unbalanced current clipping coefficient as described above.
The embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored, where the computer program is executed by a processor to perform the steps of the method for determining a three-phase unbalanced current clipping coefficient as described above.
The method, the device and the storage medium for determining the amplitude limiting coefficient of the three-phase unbalanced current provided by the embodiment of the application acquire the three-phase current data of the load equipment which is acquired in each sampling control period; correcting the three-phase current data to obtain actual current data corresponding to the three-phase current data; carrying out coordinate transformation and low-pass filtering processing on the actual current data, and calculating to obtain the current amplitude of the unbalanced current of each phase current in the three-phase current passing through the current load equipment at the acquisition time of the sampling control period; and comparing the maximum current amplitude in the three-phase current with the rated current value of the reactive compensation equipment, and calculating to obtain an amplitude limiting coefficient for limiting the unbalanced current of each phase current in the three-phase current passing through the current load equipment in the sampling control period. Therefore, the amplitude limiting coefficient for adjusting the three-phase current can be accurately determined, the given adjustment of the three-phase current is realized, the problem of frequent faults caused by overlarge unbalanced current can be avoided, and the potential safety hazard of a client side is favorably reduced.
In order to make the aforementioned objects, features and advantages of the present application more comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.
Fig. 1 is a flowchart of a method for determining a three-phase unbalanced current clipping coefficient according to an embodiment of the present disclosure;
fig. 2 is a schematic diagram illustrating a three-phase current data calibration process according to an embodiment of the present disclosure;
fig. 3 is a schematic flowchart of another method for determining a three-phase unbalanced current clipping coefficient according to an embodiment of the present disclosure;
fig. 4 is a schematic structural diagram of an apparatus for determining a three-phase current clipping coefficient according to an embodiment of the present disclosure;
fig. 5 is a second schematic structural diagram of an apparatus for determining a three-phase current clipping coefficient according to an embodiment of the present disclosure;
fig. 6 is a schematic structural diagram of an electronic device according to an embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, 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 the embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. Every other embodiment that can be obtained by a person skilled in the art without making creative efforts based on the embodiments of the present application falls within the protection scope of the present application.
Research shows that in actual life, when three-phase load power is different or a large amount of single-phase loads exist in a used power grid, imbalance of three-phase current in the power grid is easily caused, and then, a large zero-sequence current flows through a zero line, and the zero-sequence current on the zero line can reach three times of the zero-sequence current on a phase line under the condition. In the use process of a power grid, if the current flowing through the zero line is too large, the zero line is heated, the insulating layer is aged, and the line loss is increased; if the transmission line is too long, a large zero-sequence voltage drop is generated on the zero line, so that the problem of unbalanced three-phase voltage of the user side occurs, the serious problem of electric energy quality and the potential safety hazard of the user side are caused, and therefore, how to reasonably adjust the three-phase current in the power grid becomes a problem to be solved urgently.
Based on this, the embodiment of the application provides a method for determining a three-phase unbalanced current amplitude limiting coefficient, which can determine a target amplitude limiting coefficient for adjusting a three-phase current, can avoid the problem of frequent faults caused by excessive unbalanced current, and is beneficial to reducing the potential safety hazard of a client.
Referring to fig. 1, fig. 1 is a flowchart illustrating a method for determining a three-phase unbalanced current clipping coefficient according to an embodiment of the present disclosure. As shown in fig. 1, a method for determining a three-phase unbalanced current clipping coefficient according to an embodiment of the present application includes:
s101, acquiring three-phase current data of the current passing load equipment acquired in each sampling control period.
And S102, correcting the three-phase current data to obtain actual current data corresponding to the three-phase current data.
And S103, carrying out coordinate transformation and low-pass filtering processing on the actual current data, and calculating to obtain the current amplitude of the unbalanced current of each phase current in the three-phase current passing through the current load equipment at the acquisition time of the sampling control period.
And S104, comparing the maximum current amplitude in the three-phase current with the rated current value of the reactive compensation equipment, and calculating to obtain an amplitude limiting coefficient for limiting the unbalanced current of each phase in the three-phase current flowing through the load equipment in the sampling control period.
In step S101, three-phase current data passing through the load device in each acquisition cycle is acquired at an acquisition frequency. Here, since the hardware device introduces a zero drift during the acquisition process, the acquired three-phase current data needs to be corrected to filter out the zero drift amount in the three-phase current data.
In step S102, the three-phase current data acquired for each sampling control period is corrected to obtain actual current data corresponding to the three-phase current data.
In one implementation, as shown in fig. 2, fig. 2 is a schematic diagram of a correction process of three-phase current data according to an embodiment of the present application. As shown in fig. 2, step S101 includes: and step S1011, acquiring a correction coefficient of a sampling channel used for acquiring the three-phase current data. And step S1012, verifying whether the three-phase current data is correct. And S1013, if the three-phase current data are correct, filtering zero drift data in the three-phase current data to obtain the three-phase current data with the zero drift filtered. And S1014, calculating actual current data corresponding to the three-phase current data based on the three-phase current data subjected to the zero drift filtering and the correction coefficient.
Here, the correction coefficient is set in advance according to the sampling channel of the data acquisition device, and the correction coefficient is set for the purpose of performing amplification processing on the acquired three-phase current data. In order to facilitate data transmission in the data transmission process, firstly, the acquired analog signals of the three-phase current are converted into digital signals of the three-phase current; then, in order to save the transmission amount of data, when the digital signal of the three-phase current is transmitted as the three-phase current data, the three-phase current data is reduced as a whole by sampling the correction coefficient of the channel; therefore, after the receiving end receives the three-phase current data, in order to accurately obtain the amplitude limiting coefficient of the three-phase current, the received three-phase current data needs to be amplified and restored through the correction coefficient of the sampling channel.
Therefore, in step S1011, while the three-phase current data of each sampling control period is acquired, the correction coefficient of the sampling channel for transmitting the three-phase current data of the sampling control period can also be acquired to perform the amplification reduction of the three-phase current data in the subsequent process.
Here, in the data transmission process, there may be an error in the data transmission process due to problems such as interference on a channel, and in the case that the received data itself has a problem, even if zero drift data in the three-phase current data is effectively filtered, the amplitude limiting coefficient of the three-phase current is calculated, and the obtained amplitude limiting coefficient is still inaccurate, so that it is undoubtedly invalid to perform imbalance correction on the three-phase current using the inaccurate amplitude limiting coefficient, and therefore, when the obtained data itself is incorrect, subsequent processing is performed on the obtained data, which increases unnecessary data processing amount, and cannot perform effective correction on the three-phase current.
Therefore, in step S1012, in order to avoid performing subsequent processing on the three-phase current data when the error data is received, after the three-phase current data is received, first, whether the received three-phase current data is correct is verified, specifically, a first check value of the three-phase current data may be calculated according to the received three-phase current data, and whether the received first check value is consistent with a second check value of the three-phase current data calculated before the transmission of the three-phase current data is compared; and if the three-phase current data are consistent, the received three-phase current data can be confirmed to be correct data, and the correct three-phase current data are written into a buffer area so as to be filtered out the zero drift data in the three-phase current data.
The second check value is calculated by the data sending end according to the collected three-phase current data before the three-phase current data is sent, and can be transmitted to the receiving end together with the three-phase current data, and specifically, the second check value can be transmitted at the end of the three-phase current data; or the three-phase current data and the three-phase current data can form a data packet, the data packet is transmitted to a receiving end in the form of the data packet, and the data packet can be set according to actual conditions without limitation.
In step S1013, if it is determined that the acquired three-phase current data is correct, the zero drift data in the three-phase current data of the sampling control period is filtered.
The method for filtering the zero drift data can filter the zero drift data in a mode of finding out a drift rule, and can also filter the zero drift data in a mode of digital filtering, physical filtering and the like, and the method is not limited in the process, so that the filtered three-phase current data is obtained.
In step S1014, after the three-phase current data with the zero drift filtered out is obtained, the received current data may be amplified and reduced by multiplying the correction coefficient of the acquisition channel, so as to obtain actual current data used for calculating the unbalanced component in the three-phase current data in the subsequent process.
In one embodiment, step S103 includes: carrying out coordinate transformation and low-pass filtering processing on the actual current data, and extracting a plurality of unbalanced components from the actual current data; and calculating the current amplitude of the unbalanced current of each phase current in the three-phase current passing through the load equipment at the acquisition time of the sampling control period by using the plurality of unbalanced components.
Here, since the current fundamental wave data is obtained by conversion, a plurality of unbalanced components of each phase current can be extracted from the current fundamental wave data by calculation, wherein the unbalanced components include an active component and a reactive component of the negative sequence current and an active component and a reactive component of the zero sequence current.
In one embodiment, the coordinate transformation and low-pass filtering process on the actual current data to extract a plurality of imbalance components from the actual current data includes: respectively carrying out negative sequence rotation coordinate transformation and zero sequence rotation coordinate transformation on the actual current data, and converting the actual current data from a static coordinate system to a negative sequence rotation coordinate system and a zero sequence rotation coordinate system; respectively converting actual current data under the negative sequence rotating coordinate system and the zero sequence rotating coordinate system from a three-phase coordinate system to a two-phase coordinate system to respectively obtain negative sequence current data and zero sequence current data under the two-phase coordinate system; and respectively carrying out low-pass filtering processing on the negative sequence current data and the zero sequence current data to obtain a plurality of unbalanced components.
In the step, because the detected current is alternating current, actual current data obtained after processing three-phase current data of the alternating current is vector data and is in a static coordinate system, and the actual current data comprises a negative sequence component, a zero sequence component and a harmonic component, negative sequence rotation coordinate transformation and zero sequence rotation coordinate transformation can be respectively carried out on the actual current data according to the rotation rate of the alternating current in the step, and the actual current data is converted into a negative sequence rotation coordinate system and a zero sequence rotation coordinate system from the static coordinate system; and converting actual current data in the negative sequence rotating coordinate system and the zero sequence rotating coordinate system from the three-phase coordinate system to the two-phase coordinate system to respectively obtain negative sequence current data and zero sequence current data in the two-phase coordinate system.
Wherein the unbalance components comprise active and reactive components of the negative sequence current and active and reactive components of the zero sequence current.
And respectively carrying out low-pass filtering processing on the negative sequence current data and the zero sequence current data to obtain a plurality of unbalanced components, namely obtaining the active component and the reactive component of the negative sequence current and the active component and the reactive component of the zero sequence current.
Because the obtained negative sequence current data and zero sequence current data comprise fundamental wave components and harmonic components, the negative sequence current data and the zero sequence current data are subjected to mean value filtering processing to avoid interference of the harmonic components, and a plurality of unbalanced components are extracted while the harmonic components are filtered.
Specifically, the current amplitude of the unbalanced current of each phase current is calculated by the following steps:
decomposing the zero-sequence current in the three-phase current data into: i is0＝Ip0+Iq0(ii) a The positive sequence current is decomposed into: i is1＝Ip1+Iq1(ii) a The negative sequence current is decomposed into: i is2＝Ip2+Iq2(ii) a Thus, the three-phase current can then be expressed as:
Figure BDA0003184260340000111
where 0 represents a zero sequence component, 1 represents a positive sequence component, 2 represents a negative sequence component, p represents an active component, q represents a reactive component, and exemplary, Ip0The zero sequence active component is represented.
Here, the specific explanation is divided into two layers:
(1) the active or reactive components may be converted into each other by multiplying by "j", for example, the active component multiplied by j may be converted into a reactive component or a negative reactive component; similarly, the reactive component multiplied by j becomes the active component or the negative active component. Where multiplying by "j" represents a 90 degree counterclockwise rotation, multiplying by "-j" represents a 90 degree clockwise rotation.
(2) Phase relationship between active and reactive components: specifically, there are two types: firstly, the active component leads the reactive component by 90 degrees; secondly, the reactive component leads the active component by 90 degrees. For example:
ip＝Ipcoswt；
iq＝Iqsinwt；
indicating that the active component leads the reactive component by 90 degrees. If:
ip＝Ipsinwt；
iq＝Iqcoswt；
representing the real component lagging the reactive component by 90 degrees.
For the case where the active component leads the reactive component by 90 degrees:
according to the symmetrical component method, the formula for synthesizing the three-phase current by each sequence component comprises the following steps:
Figure BDA0003184260340000121
correspondingly:
Iasqrt (p component)2Component + q2)＝sqrt((IP0+IP1+IP2)2+(Iq0+Iq1+Iq2)2)；
Figure BDA0003184260340000122
Wherein, I0＝Ip0+Iq0，I1＝Ip1+Iq1，I2＝Ip2+Iq2；
Correspondingly:
Ibsqrt (p component)2Component + q2)＝sqrt((Ip0-0.5*Ip1-0.866*Iq1-0.5*Ip2+0.866*Iq2)2+(Iq0-0.5*Iq1+0.866*Ip1-0.5*Iq2-0.866*Ip2)2)；
The same principle is that:
Figure BDA0003184260340000131
correspondingly:
Icsqrt (p component)2Component + q2)＝sqrt((Ip0-0.5*Ip1+0.866*Iq1-0.5*Ip2-0.866*Iq2)2+(Iq0-0.5*Iq1-0.866*Ip1-0.5*Iq2+0.866*Ip2)2)；
For the case where the real component lags the reactive component by 90 degrees:
according to the symmetrical component method, the formula for synthesizing the three-phase current by each sequence component comprises the following steps:
Figure BDA0003184260340000132
correspondingly:
Iasqrt (p component)2Component + q2)＝sqrt((IP0+IP1+IP2)2+(Iq0+Iq1+Iq2)2)；
Figure BDA0003184260340000133
Wherein, I0＝Ip0+Iq0，I1＝Ip1+Iq1，I2＝Ip2+Iq2；
Correspondingly: i isbSqrt (p component)2Component + q2)
＝sqrt((Ip0-0.5*Ip1+0.866*Iq1-0.5*Ip2-0.866*Iq2)2+(Iq0-0.5*Iq1-0.866*Ip1-0.5*Iq2+0.866*Ip2)2)；
The same principle is that:
Figure BDA0003184260340000134
correspondingly:
Icsqrt (p component)2Component + q2)
＝sqrt((Ip0-0.5*Ip1-0.866*Iq1-0.5*Ip2+0.866*Iq2)2+(Iq0-0.5*Iq1+0.866*Ip1-0.5*Iq2-0.866*Ip2)2)；
Further, by the above calculation, the current amplitude of the unbalanced current of each phase current among the three-phase currents flowing through the load device at the acquisition time of the sampling control period can be obtained.
In step S104, the maximum current amplitude of the three-phase currents is compared with the rated current value of the reactive power compensation equipment, and the limiter coefficient for limiting the unbalanced current of each phase current of the three-phase currents flowing through the load equipment in the sampling control period is calculated.
In an implementation manner, as shown in fig. 3, fig. 3 is a schematic flowchart of another method for determining a three-phase unbalanced current clipping coefficient according to an embodiment of the present application. As shown in fig. 3, the determining method includes:
s301, acquiring three-phase current data of the current passing load equipment acquired in each sampling control period.
S302, correcting the three-phase current data to obtain actual current data corresponding to the three-phase current data.
And S303, performing coordinate transformation and low-pass filtering processing on the accumulated actual current data, and calculating to obtain the current amplitude of the unbalanced current of each phase current in the three-phase current passing through the current load equipment at the acquisition time of the sampling control period.
S304, comparing the maximum current amplitude in the three-phase current serving as a target current amplitude with the rated current value of the reactive compensation equipment, and calculating to obtain an amplitude limiting coefficient for limiting unbalanced current of each phase in the three-phase current passing through the current load equipment in the sampling control period.
The descriptions of S301 to S304 may refer to the descriptions of S101 to S104, and the same technical effects can be achieved, which are not described in detail.
S305, correcting the plurality of unbalanced components obtained by calculating the three-phase current data acquired in the sampling control period by using the amplitude limiting coefficient to obtain a plurality of corrected unbalanced components.
In this step, for each sampling control period, each unbalanced component in the three-phase current passing through the load device at the sampling time of the sampling control period is corrected by the limiter coefficient corresponding to the three-phase current in the sampling control period, so as to obtain a plurality of unbalanced components corrected in the sampling control period.
And S306, overlapping the corrected unbalanced components according to the original phase of each unbalanced component in each phase of current respectively to obtain corrected three-phase current data corresponding to the sampling control period.
In this step, the plurality of unbalanced components corrected in the sampling control period are used, and the plurality of unbalanced components corrected in the sampling control period are superimposed according to the original phase of each unbalanced component in each phase current, so that the three-phase current data corrected in the sampling control period corresponding to the three-phase current is corrected.
The method for determining the amplitude limiting coefficient of the three-phase unbalanced current provided by the embodiment of the application acquires the three-phase current data of the current passing load equipment acquired in each sampling control period; correcting the three-phase current data to obtain actual current data corresponding to the three-phase current data; carrying out coordinate transformation and low-pass filtering processing on the actual current data, and calculating to obtain the current amplitude of the unbalanced current of each phase current in the three-phase current passing through the current load equipment at the acquisition time of the sampling control period; comparing the maximum current amplitude value in the three-phase current with the rated current value of the reactive compensation equipment, and calculating to obtain an amplitude limiting coefficient for limiting the unbalanced current of each phase current in the three-phase current passing through the current load equipment in the sampling control period; correcting the three-phase current data acquired in the sampling control period by using the amplitude limiting coefficient, and calculating to obtain a plurality of unbalanced components to obtain a plurality of corrected unbalanced components; and superposing the corrected unbalanced components according to the original phase of each unbalanced component in each phase of current respectively to obtain corrected three-phase current data corresponding to the sampling control period. Therefore, the amplitude limiting coefficient for adjusting the three-phase current can be accurately determined, the given adjustment of the three-phase current is realized through the amplitude limiting coefficient, the problem of frequent faults caused by overlarge unbalanced current can be avoided, and the potential safety hazard of a client side is favorably reduced.
Referring to fig. 4 and 5, fig. 4 is a first schematic structural diagram of a device for determining a three-phase current clipping coefficient according to an embodiment of the present disclosure, and fig. 5 is a second schematic structural diagram of the device for determining a three-phase current clipping coefficient according to an embodiment of the present disclosure. As shown in fig. 4, the determining means 400 includes:
a data acquisition module 410, configured to acquire three-phase current data of the current-passing load device acquired in each sampling control period;
the correction processing module 420 is configured to perform correction processing on the three-phase current data to obtain actual current data corresponding to the three-phase current data;
the amplitude calculation module 430 is configured to perform coordinate transformation and low-pass filtering on the actual current data, and calculate a current amplitude of an unbalanced current of each phase current in three-phase currents flowing through the load device at the acquisition time of the sampling control period;
and the coefficient calculation module 440 is configured to compare the maximum current amplitude in the three-phase current with a rated current value of the reactive compensation equipment, and calculate an amplitude limiting coefficient for limiting an unbalanced current of each phase of the three-phase current flowing through the load equipment in the sampling control period.
Further, as shown in fig. 5, the determining apparatus 400 further includes a current correcting module 450, where the current correcting module 450 is configured to:
correcting the three-phase current data acquired in the sampling control period by using the amplitude limiting coefficient, and calculating to obtain a plurality of unbalanced components to obtain a plurality of corrected unbalanced components;
and superposing the corrected unbalanced components according to the original phase of each unbalanced component in each phase of current respectively to obtain corrected three-phase current data corresponding to the sampling control period.
Further, when the correction processing module 420 is configured to perform correction processing on the three-phase current data to obtain actual current data corresponding to the three-phase current data, the correction processing module 420 is configured to:
acquiring a correction coefficient of a sampling channel used for acquiring the three-phase current data;
checking whether the three-phase current data are correct or not;
if the three-phase current data are correct, filtering zero drift data in the three-phase current data to obtain the three-phase current data with the zero drift filtered;
and calculating actual current data corresponding to the three-phase current data based on the three-phase current data subjected to zero drift filtering and the correction coefficient.
Further, when the amplitude calculation module 430 is configured to perform coordinate transformation and low-pass filtering on the actual current data, and calculate a current amplitude of an unbalanced current of each phase current in the three-phase current flowing through the load device at the acquisition time of the sampling control period, the amplitude calculation module 430 is configured to:
carrying out coordinate transformation and low-pass filtering processing on the actual current data, and extracting a plurality of unbalanced components from the actual current data;
and calculating the current amplitude of the unbalanced current of each phase current in the three-phase current passing through the load equipment at the acquisition time of the sampling control period by using the plurality of unbalanced components.
Further, the unbalanced components include active and reactive components of the negative sequence current, and active and reactive components of the zero sequence current.
Further, when the amplitude calculation module 430 is configured to perform coordinate transformation and low-pass filtering on the actual current data, and extract a plurality of imbalance components from the actual current data, the amplitude calculation module 430 is configured to:
respectively carrying out negative sequence rotation coordinate transformation and zero sequence rotation coordinate transformation on the actual current data, and converting the accumulated actual current data from a static coordinate system to a negative sequence rotation coordinate system and a zero sequence rotation coordinate system;
respectively converting actual current data under the negative sequence rotating coordinate system and the zero sequence rotating coordinate system from a three-phase coordinate system to a two-phase coordinate system to respectively obtain negative sequence current data and zero sequence current data under the two-phase coordinate system;
and respectively carrying out low-pass filtering processing on the negative sequence current data and the zero sequence current data to obtain a plurality of unbalanced components.
Data is transmitted between the modules in a parameter transmission mode, and information transmitted by the interface is transmitted between the modules in a structural body packaging mode. The operation control is realized strictly according to the function calling relation among the modules. A lot of semaphores are defined between modules for mutual exclusion and synchronization between modules. A state machine is also introduced in the part with process control, and the flow is strictly controlled. All the flows among the modules are strictly carried out according to the logic flow of the operation control.
The device for determining the three-phase current amplitude limiting coefficient, provided by the embodiment of the application, acquires the three-phase current data which are acquired in each sampling control period and pass through the current load equipment; correcting the three-phase current data to obtain actual current data corresponding to the three-phase current data; performing coordinate transformation and low-pass filtering processing on the actual current data, and calculating to obtain the current amplitude of the unbalanced current of each phase current in the three-phase current passing through the current load equipment at the acquisition time of the sampling control period; and comparing the maximum current amplitude in the three-phase current with the rated current value of the reactive compensation equipment, and calculating to obtain an amplitude limiting coefficient for limiting the unbalanced current of each phase current in the three-phase current passing through the current load equipment in the sampling control period. Therefore, the amplitude limiting coefficient for adjusting the three-phase current can be accurately determined, the given adjustment of the three-phase current is realized, the problem of frequent faults caused by overlarge unbalanced current can be avoided, and the potential safety hazard of a client side is favorably reduced.
Referring to fig. 6, fig. 6 is a schematic structural diagram of an electronic device according to an embodiment of the present disclosure. As shown in fig. 6, the electronic device 600 includes a processor 610, a memory 620, and a bus 630.
The memory 620 stores machine-readable instructions executable by the processor 610, when the electronic device 600 runs, the processor 610 communicates with the memory 620 through the bus 630, and when the machine-readable instructions are executed by the processor 610, the steps of the method for determining a three-phase unbalanced current clipping coefficient in the method embodiments shown in fig. 1 and fig. 2 may be executed.
An embodiment of the present application further provides a computer-readable storage medium, where a computer program is stored on the computer-readable storage medium, and when the computer program is executed by a processor, the step of the method for determining a three-phase unbalanced current clipping coefficient in the method embodiments shown in fig. 1 and fig. 2 may be executed.
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.
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 ways. The above-described embodiments of the apparatus are merely illustrative, and for example, the division of the units is only one logical division, and there may be other divisions when actually implemented, and 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 of devices or units through some communication interfaces, 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 functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a non-volatile computer-readable storage medium executable by a processor. Based on such understanding, the technical solution of the present application or portions thereof that substantially contribute to the prior art may be embodied in the form of a software product stored in a storage medium and including 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: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.
Finally, it should be noted that: the above-mentioned embodiments are only specific embodiments of the present application, and are used for illustrating the technical solutions of the present application, but not limiting the same, and the scope of the present application is not limited thereto, and although the present application is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: any person skilled in the art can modify or easily conceive the technical solutions described in the foregoing embodiments or equivalent substitutes for some technical features within the technical scope disclosed in the present application; such modifications, changes or substitutions do not depart from the spirit and scope of the exemplary embodiments of the present application, and are intended to be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (10)

1. A method for determining a three-phase unbalanced current clipping coefficient, the method comprising:
acquiring three-phase current data of the overcurrent load equipment acquired in each sampling control period;
correcting the three-phase current data to obtain actual current data corresponding to the three-phase current data;
carrying out coordinate transformation and low-pass filtering processing on the actual current data, and calculating to obtain the current amplitude of the unbalanced current of each phase current in the three-phase current passing through the current load equipment at the acquisition time of the sampling control period;
and comparing the maximum current amplitude in the three-phase current with the rated current value of the reactive compensation equipment, and calculating to obtain an amplitude limiting coefficient for limiting the unbalanced current of each phase current in the three-phase current passing through the current load equipment in the sampling control period.
2. The determination method according to claim 1, wherein the performing the correction processing on the three-phase current data to obtain actual current data corresponding to the three-phase current data includes:
acquiring a correction coefficient of a sampling channel used for acquiring the three-phase current data;
checking whether the three-phase current data are correct or not;
if the three-phase current data are correct, filtering zero drift data in the three-phase current data to obtain the three-phase current data with the zero drift filtered;
and calculating actual current data corresponding to the three-phase current data based on the three-phase current data subjected to zero drift filtering and the correction coefficient.
3. The method for determining according to claim 1, wherein the performing coordinate transformation and low-pass filtering processing on the actual current data to calculate a current amplitude of an unbalanced current of each phase current in three-phase currents flowing through a load device at a collection time of the sampling control period includes:
carrying out coordinate transformation and low-pass filtering processing on the actual current data, and extracting a plurality of unbalanced components from the actual current data;
and calculating the current amplitude of the unbalanced current of each phase current in the three-phase current passing through the load equipment at the acquisition time of the sampling control period by using the plurality of unbalanced components.
4. A method of determination according to claim 3, characterized in that the unbalance components comprise the active and reactive components of a negative sequence current and the active and reactive components of a zero sequence current.
5. The method of determining according to claim 3, wherein after said calculating a clipping coefficient for limiting an unbalanced current of each phase current among three phase currents flowing through the load device during the sampling control period, the method of determining further comprises:
correcting the three-phase current data acquired in the sampling control period by using the amplitude limiting coefficient, and calculating to obtain a plurality of unbalanced components to obtain a plurality of corrected unbalanced components;
and superposing the corrected unbalanced components according to the original phase of each unbalanced component in each phase of current respectively to obtain corrected three-phase current data corresponding to the sampling control period.
6. The method according to claim 3, wherein the coordinate transformation and low-pass filtering processing of the actual current data to extract a plurality of imbalance components from the actual current data includes:
respectively carrying out negative sequence rotation coordinate transformation and zero sequence rotation coordinate transformation on the actual current data, and converting the actual current data from a static coordinate system to a negative sequence rotation coordinate system and a zero sequence rotation coordinate system;
respectively converting actual current data under the negative sequence rotating coordinate system and the zero sequence rotating coordinate system from a three-phase coordinate system to a two-phase coordinate system to respectively obtain negative sequence current data and zero sequence current data under the two-phase coordinate system;
and respectively carrying out low-pass filtering processing on the negative sequence current data and the zero sequence current data to obtain a plurality of unbalanced components.
7. A device for determining a three-phase current clipping factor, said device comprising:
the data acquisition module is used for acquiring the three-phase current data of the overcurrent load equipment acquired in each sampling control period;
the correction processing module is used for correcting the three-phase current data to obtain actual current data corresponding to the three-phase current data;
the amplitude calculation module is used for carrying out coordinate transformation and low-pass filtering processing on the actual current data and calculating to obtain the current amplitude of the unbalanced current of each phase current in the three-phase current passing through the current load equipment at the acquisition time of the sampling control period;
and the coefficient calculation module is used for comparing the maximum current amplitude in the three-phase current with the rated current value of the reactive compensation equipment, and calculating to obtain the amplitude limiting coefficient for limiting the unbalanced current of each phase in the three-phase current passing through the current load equipment in the sampling control period.
8. The determination apparatus of claim 7, further comprising a current correction module to:
correcting the three-phase current data acquired in the sampling control period by using the amplitude limiting coefficient, and calculating to obtain a plurality of unbalanced components to obtain a plurality of corrected unbalanced components;
and superposing the corrected unbalanced components according to the original phase of each unbalanced component in each phase of current respectively to obtain corrected three-phase current data corresponding to the sampling control period.
9. An electronic device, comprising: a processor, a memory and a bus, the memory storing machine readable instructions executable by the processor, the processor and the memory communicating over the bus when an electronic device is operating, the machine readable instructions when executed by the processor performing the steps of the method of determining three-phase unbalanced current clipping coefficients as claimed in any one of claims 1 to 6.
10. A computer-readable storage medium, having stored thereon a computer program which, when being executed by a processor, carries out the steps of the method for determining a three-phase unbalance current limiting coefficient according to any one of claims 1 to 6.
CN202110856550.3A 2021-07-28 2021-07-28 Method and device for determining amplitude limiting coefficient of three-phase unbalanced current and storage medium Pending CN113555885A (en)

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