CN107797031A - The detection method and device of arc fault - Google Patents

The detection method and device of arc fault Download PDF

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Publication number
CN107797031A
CN107797031A CN201610776328.1A CN201610776328A CN107797031A CN 107797031 A CN107797031 A CN 107797031A CN 201610776328 A CN201610776328 A CN 201610776328A CN 107797031 A CN107797031 A CN 107797031A
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load model
domain load
time domain
updating
time
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CN107797031B (en
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邬佳希
陈献民
赵晓冬
赵韬敏
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Shanghai Fudan Microelectronics Group Co Ltd
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Shanghai Fudan Microelectronics Group Co Ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
    • G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials

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  • General Physics & Mathematics (AREA)
  • Emergency Protection Circuit Devices (AREA)

Abstract

A kind of detection method and device of arc fault.Methods described includes：Using default time domain load module, the electric signal of circuit to be detected is sampled, and calculates the electric signal residual values of the sampled point in current calculation cycle；According to the electric signal residual values of the sampled point of the current calculation cycle, judge whether the slowdown monitoring circuit current time to be checked occurs arc fault；When arc fault does not occur for the slowdown monitoring circuit to be checked, according to the electric signal actual value of the current time sampled point and the parameter more new state of the time domain load module, the parameter of the time domain load module is updated, including：Exponent number and coefficient；Using the time domain load module after renewal, the electric signal of circuit to be detected is sampled again, and judges whether the slowdown monitoring circuit to be checked occurs arc fault in subsequent time.Using such scheme, the accuracy of detection of the detection method based on time domain load module can be improved.

Description

Arc fault detection method and device
Technical Field
The invention relates to the technical field of electric arcs, in particular to a method and a device for detecting an electric arc fault.
Background
The UL1699 standard defines arcing as the generation of luminescence by the passage of current through an insulating medium, usually accompanied by local volatilization of the electrodes. Meanwhile, the UL1699 standard defines an arc fault as an unintentional arcing in the circuit, and the arc generated when the switch is closed and opened and the load is switched is not an arc fault.
Arc faults are accompanied by the generation of significant amounts of heat which can burn the circuit, cause a fire, and even cause injury or death. Relevant research studies show that the arc faults cause huge economic losses every year in China. In general, the reasons for the occurrence of an arc fault include: aging of the insulation of the wires on the circuit, damage to the wires, and loose wire connections.
At present, there is an arc fault detection method based on a time domain load model. The method mainly judges whether the electric signal is an arc or not under certain conditions, otherwise, the electric signal is the arc, accumulates the number of the arcs, and judges whether the arc fault is generated according to an accumulated result.
However, the detection accuracy of the existing detection method based on the time domain load model still cannot meet the requirements of users.
Disclosure of Invention
The invention solves the technical problem of how to improve the detection precision of the detection method based on the time domain load model.
In order to solve the above technical problem, an embodiment of the present invention provides a method for detecting an arc fault, where the method includes: sampling an electric signal of a circuit to be detected by adopting a preset time domain load model to obtain an electric signal actual value of the electric signal at a sampling point at the current moment, and calculating an electric signal residual value of the sampling point in the current calculation period according to the electric signal actual value of the sampling point of the electric signal in the current calculation period; judging whether the current moment of the circuit to be detected has an arc fault according to the residual value of the electric signal of the sampling point of the current calculation period; when the circuit to be detected has no arc fault, updating the parameters of the time domain load model according to the actual values of the electric signals of the sampling points at the current moment and the parameter updating state of the time domain load model, wherein the updating state comprises the following steps: the order and coefficient; and sampling the electric signal of the circuit to be detected again by adopting the updated time domain load model, and judging whether the circuit to be detected has an arc fault at the next moment.
Optionally, the determining, according to the residual value of the electrical signal at the sampling point in the current calculation period, whether an arc fault occurs at the current time of the circuit to be detected includes: judging whether the current moment of the circuit to be detected generates an electric arc or not according to the residual value of the electric signal of the sampling point in the current calculation period; and updating the value of the arc counter according to the judgment result, and judging whether the current moment of the circuit to be detected has the arc fault according to the updated value of the arc counter.
Optionally, the updating the parameter of the time-domain load model according to the actual value of the electrical signal of the current time sampling point and the parameter update state of the time-domain load model includes: updating the order of the time domain load model according to the actual value of the electric signal of the sampling point at the current moment and the parameter updating state of the time domain load model; and updating the coefficient of the time domain load model according to the updated order of the time domain load model.
Optionally, the updating the order of the time-domain load model according to the actual value of the electrical signal of the current time sampling point and the parameter update state of the time-domain load model includes: detecting whether the circuit to be detected carries out load switching at the current moment according to the actual value of the electric signal of the sampling point at the current moment; detecting whether the time domain load model is in a parameter updating process; and updating the order of the time domain load model according to the detection results of the parameter updating states of the circuit to be detected and the time domain load model.
Optionally, the detecting whether the circuit to be detected performs load switching at the current time includes: and when the residual value of the electric signal at the sampling point of the current moment is larger than the preset maximum residual value, determining that the circuit to be detected performs load switching at the current moment, otherwise, determining that the circuit to be detected does not perform load switching at the current moment.
Optionally, the detecting whether the time-domain load model is in a parameter updating process includes: and reading the value of a first register, and detecting whether the time domain load model is in the parameter updating process according to the read value of the first register, wherein the first register is suitable for storing the value of the identification bit of whether the time domain load model is in the parameter updating process.
Optionally, the updating the order of the time-domain load model according to the detection result of the parameter update state of the circuit to be detected and the time-domain load model includes: when the circuit to be detected is subjected to load switching at the current moment and the time domain load model is not in the parameter updating process, selecting a corresponding order from N preset orders as the order of the time domain load model according to a preset rule, triggering an interrupt timer to start timing, and updating the values of a first register and a second register; the second register is suitable for storing the value of the identification bit of the parameter updating stage where the time domain load model is located in the current parameter updating process, wherein N is more than or equal to 2 and is a positive integer.
Optionally, the updating the order of the time-domain load model according to the detection result of the parameter update state of the circuit to be detected and the time-domain load model further includes: when the circuit to be detected is not subjected to load switching at the current moment or the time domain load model is in the parameter updating process, reading the value of the second register, and determining whether the order of the time domain load model is updated or not according to the value of the second register; when the order of the time domain load model is determined to be updated, reading the value of the interrupt timer, and determining whether the updating time length of the latest order updating reaches the preset time length; and when the updating time length of the latest order updating reaches a preset time length, selecting a corresponding order from the N orders as the order of the time domain load model according to the preset rule, triggering an interrupt timer to start timing, and updating the value of a corresponding register.
Optionally, the preset rule includes: in the same parameter updating process, when the order of the time domain load model is updated for the 1 st time, the minimum order of the N orders is selected as the order of the time domain load model, and when the order of the time domain load model is updated for the 2 nd to N times, the selected orders are sequentially increased.
Optionally, the updating the order of the time-domain load model according to the detection result of the parameter update state of the circuit to be detected and the time-domain load model further includes: and when the order of the time domain load model is determined to be not updated according to the value of the second register, keeping the current order of the time domain load model unchanged.
Optionally, the updating the order of the time-domain load model according to the detection result of the parameter update state of the circuit to be detected and the time-domain load model further includes: and when the updating time length of the latest order updating does not reach the preset time length, keeping the current order of the time domain load model unchanged.
Optionally, the method further comprises: when the actual values of the electric signals of all sampling points of the electric signals in the current calculation period are not obtained, updating the order and the coefficient of the time domain load model according to the actual values of the electric signals of the sampling points at the current moment and the parameter updating state of the time domain load model, and judging whether the circuit to be detected has the arc fault at the next moment according to the updated time domain load model.
Optionally, the time domain load model is an ARMA model.
Optionally, the electrical signal is a voltage signal or a current signal.
The embodiment of the invention also provides a device for detecting the arc fault, which comprises: the sampling unit is suitable for sampling the electric signal of the circuit to be detected by adopting a preset time domain load model to obtain the actual value of the electric signal of the sampling point of the electric signal at the current moment; the computing unit is suitable for computing the residual value of the electric signal of the sampling point in the current computing period according to the actual value of the electric signal of the sampling point of the electric signal in the current computing period; the judging unit is suitable for judging whether the current moment of the circuit to be detected has an arc fault according to the residual value of the electric signal of the sampling point of the current calculation period; the first updating unit is suitable for updating the parameters of the time domain load model according to the actual values of the electric signals of the sampling points at the current moment and the parameter updating state of the time domain load model when the circuit to be detected has no arc fault, and comprises the following steps: the sampling unit and the calculating unit sample and calculate the electric signal of the circuit to be detected again by adopting the updated time domain load model, and the judging unit judges whether the circuit to be detected has the arc fault at the next moment.
Optionally, the determining unit includes: the first judgment subunit is suitable for judging whether the current moment of the circuit to be detected generates electric arcs according to the electric signal residual value of the sampling point in the current calculation period; and the second judgment subunit is suitable for updating the value of the arc counter according to the judgment result and judging whether the current moment of the circuit to be detected has the arc fault according to the updated value of the arc counter.
Optionally, the first updating unit includes: the first updating subunit is suitable for updating the order of the time domain load model according to the actual value of the electric signal of the current sampling point and the parameter updating state of the time domain load model; and the second updating subunit is suitable for updating the coefficient of the time domain load model according to the updated order of the time domain load model.
Optionally, the first updating subunit includes: the first detection module is suitable for detecting whether the circuit to be detected carries out load switching at the current moment according to the actual value of the electric signal of the sampling point at the current moment; the second detection module is suitable for detecting whether the time domain load model is in a parameter updating process; and the updating module is suitable for updating the order of the time domain load model according to the detection results of the parameter updating states of the circuit to be detected and the time domain load model.
Optionally, the first detection module is adapted to determine that the circuit to be detected performs load switching at the current time when an electrical signal residual value of the electrical signal at a current time sampling point is greater than a preset maximum residual value, and otherwise determine that the circuit to be detected does not perform load switching at the current time.
Optionally, the second detecting module is adapted to read a value of a first register, and detect whether the time-domain load model is in a parameter updating process according to the read value of the first register, where the first register is adapted to store a value of an identification bit of whether the time-domain load model is in the parameter updating process.
Optionally, the update module includes: the first updating submodule is suitable for selecting a corresponding order from N preset orders as the order of the time domain load model according to a preset rule when the load of the circuit to be detected is switched at the current moment and the time domain load model is not in the parameter updating process, triggering an interrupt timer to start timing and updating the values of the first register and the second register; the second register is suitable for storing the value of the identification bit of the parameter updating stage where the time domain load model is located in the current parameter updating process, wherein N is more than or equal to 2 and is a positive integer.
Optionally, the update module further includes: the first reading submodule is suitable for reading the value of the second register when the circuit to be detected is not subjected to load switching at the current moment or the time domain load model is in a parameter updating process, and determining whether the order of the time domain load model is updated or not according to the value of the second register; the second reading submodule is suitable for reading the value of the interrupt timer when the order of the time domain load model is determined to be updated, and determining whether the updating time length of the latest order updating reaches the preset time length; and the first processing submodule is suitable for selecting a corresponding order from the N orders as the order of the time domain load model according to the preset rule when the updating time length of the latest order updating reaches the preset time length, triggering an interrupt timer to start timing and updating the value of a corresponding register.
Optionally, the preset rule includes: in the same parameter updating process, when the order of the time domain load model is updated for the 1 st time, the minimum order of the N orders is selected as the order of the time domain load model, and when the order of the time domain load model is updated for the 2 nd to N times, the selected orders are sequentially increased.
Optionally, the update module further includes: and the second processing submodule is suitable for keeping the current order of the time domain load model unchanged when the order of the time domain load model is determined not to be updated according to the value of the second register.
Optionally, the update module further includes: and the third processing submodule is suitable for keeping the current order of the time domain load model unchanged when the updating time length of the latest order updating does not reach the preset time length.
Optionally, the apparatus further comprises: and the second updating unit is suitable for updating the order and the coefficient of the time domain load model according to the electric signal actual value of the sampling point at the current moment and the parameter updating state of the time domain load model when the electric signal actual values of all the sampling points of the electric signal in the current computing period are not obtained, so as to judge whether the circuit to be detected has the arc fault at the next moment according to the updated time domain load model.
Optionally, the time domain load model is an ARMA model.
Optionally, the electrical signal is a voltage signal or a current signal.
Compared with the prior art, the embodiment of the invention has the advantages that:
by adopting the arc fault detection method, when the circuit to be detected has no arc fault, the order and the coefficient of the time domain load model are updated according to the actual value of the electric signal of the sampling point at the current moment and the parameter updating state of the time domain load model, so that the electric signal of the circuit to be detected can be sampled again according to the updated time domain load model, and whether the circuit to be detected has the arc fault at the next moment is judged. Because the order and the coefficient of the time domain load model change along with the change of the actual value of the electric signal of the sampling point at the current moment, compared with the time domain load model with a fixed order, the order of the time domain load model is reasonably set, the convergence time of the residual value of the electric signal of the sampling point in the current calculation period can be effectively shortened, the misjudgment of the electric arc fault is avoided, and the detection precision of the electric arc fault is improved.
Furthermore, when the load of the circuit to be detected is switched, corresponding transient pulses are more easily generated on the electrical signals, so that when the load of the circuit to be detected is switched, the order of the time domain load model is updated, the electrical signal residual value of the sampling point in the current calculation period is calculated by using the updated time domain load model, the convergence time of the electrical signal residual value of the sampling point can be effectively shortened, the misjudgment of the arc fault is avoided, and the detection precision of the arc fault is improved.
Further, in the same parameter updating process, when the order of the time domain load model is updated for the 1 st time, the minimum order of the N orders is selected as the order of the time domain load model, and when the order of the time domain load model is updated for the 2 nd to N times, the selected orders are sequentially increased, so that the convergence time of the residual value of the electric signals of the sampling point can be effectively shortened, and the detection precision of the arc fault is further improved.
Furthermore, an ARMA model is used as a time domain load model, so that the residual value of the electric signal of the sampling point can be more accurately calculated, and the detection precision of the arc fault is further improved.
Drawings
FIG. 1 is a flow chart of a method of detecting an arc fault in an embodiment of the invention;
FIG. 2 is a flow chart of another method of arc fault detection in an embodiment of the present invention;
FIG. 3 is a flow chart of a method for updating the order of a time-domain load model according to an embodiment of the present invention;
FIG. 4 is a flow chart of another method for updating the order of a time-domain load model in an embodiment of the invention;
FIG. 5 is a schematic diagram illustrating the residual convergence effect obtained by the arc fault detection method according to the prior art and the embodiment of the present invention;
FIG. 6 is a schematic structural diagram of an arc fault detection apparatus according to an embodiment of the present invention;
fig. 7 is a schematic structural diagram of an update subunit according to an embodiment of the present invention.
Detailed Description
At present, when an arc fault is detected by adopting a method based on a time domain load model, the order of the time domain load model is fixed and unchanged. The time domain load model has poor ability to follow the change of the electric signal, so that the residual error value between the actual value of the electric signal and the estimated value obtained by using the time domain load model is very large, and the convergence speed is slow. Therefore, when it is determined whether or not a failure has occurred at the present time based on the residual value, erroneous determination often occurs, resulting in a decrease in detection accuracy.
In view of the above problems, embodiments of the present invention provide a method for detecting an arc fault, where when no arc fault occurs in a circuit to be detected, the method may update an order and a coefficient of a time domain load model according to an actual value of an electrical signal at a sampling point at a current time and a parameter update state of the time domain load model, so that an electrical signal of a circuit to be detected may be sampled again according to the updated time domain load model, and whether an arc fault occurs in the circuit to be detected at a next time is determined. Because the order and the coefficient of the time domain load model change along with the change of the actual value of the electric signal of the sampling point at the current moment, the convergence time of the residual value of the electric signal of the sampling point in the current calculation period can be effectively shortened by reasonably setting the order of the time domain load model, the misjudgment of the arc fault is avoided, and the detection precision of the arc fault is improved.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
Referring to fig. 1, an embodiment of the present invention provides a method for detecting an arc fault, which may include the following steps:
and step 11, sampling the electric signal of the circuit to be detected by adopting a preset time domain load model, and calculating the electric signal residual value of the sampling point in the current calculation period.
In specific implementation, a preset time domain load model is adopted to sample an electric signal of a circuit to be detected, an electric signal actual value of the electric signal at a sampling point at the current moment can be obtained, and then an electric signal residual value of the sampling point in the current calculation period can be calculated according to the electric signal actual value of the sampling point of the electric signal in the current calculation period.
In specific implementation, a plurality of time domain load models can be adopted to sample the electrical signal of the circuit to be detected and calculate corresponding residual values, and the details are not limited. In an embodiment of the present invention, in order to more accurately calculate the residual value of the electrical signal at the sampling point and improve the detection accuracy of the arc fault, an Auto-regressive Moving Average Model (ARMA) may be used as a time domain load Model to sample the electrical signal of the circuit to be detected and calculate the corresponding residual value. In the embodiment of the present invention, in order to clearly describe the method for detecting an arc fault, an ARMA model is taken as an example to be described as a time domain load model.
In specific implementation, when the electrical signal of the circuit to be detected is sampled, the current signal of the circuit to be detected can be sampled, the voltage signal of the circuit to be detected can be sampled, and other signals of the circuit to be detected can be sampled without limitation.
In the specific implementation, the actual value of the electric signal of the sampling point at the current moment is taken as xtFor example, the residual value e of the electrical signal corresponding to the sampling point at the current time can be calculated by using the formula (1)t：
et＝|xt-xt′| (1)
Wherein x ist' is the electrical signal estimation value of the sampling point at the current moment obtained according to the ARMA model. Specifically, x can be calculated by formula (2)t′：
Wherein,the column vector is a column vector consisting of the actual values and residual values of the electric signals corresponding to the previous p moments of the current moment and can be obtained by calculation through a formula (3); p is the order of the ARMA model; phi is atThe coefficient vector of the ARMA model can be calculated by the formulas (4) and (5).
Mt T＝[xt-1,…,xt-p,et-1,…,et-p]T(3)
Wherein M istIs composed ofThe transposed matrix of (2).
Referring to the above-mentioned residual value e of the electrical signal corresponding to the sampling point at the current timetAnd in the calculating process, the residual value of the electric signal of each sampling point in the current calculating period is obtained. The current calculation cycle may be a half cycle of the electrical signal, may also be one cycle of the electrical signal, and may also be two cycles of the electrical signal, and the like, which is not limited specifically. It is understood that the shorter the current calculation cycle, the higher the detection accuracy of the arc fault, but the larger the calculation amount in the detection process.
And step 12, judging whether the current moment of the circuit to be detected has the arc fault according to the residual value of the electric signal of the sampling point of the current calculation period.
In an embodiment of the present invention, it may be determined whether the current time of the circuit to be detected generates an arc or not according to the residual value of the electrical signal at the sampling point in the current calculation period, and then the value of the arc counter is updated according to the determination result, and whether the current time of the circuit to be detected generates an arc fault or not is determined according to the updated value of the arc counter.
Specifically, the current calculation cycle includes M sampling points, and the residual value of the electrical signal corresponding to the ith sampling point is eiFor example, i ═ 1, M]. In an embodiment of the present invention, when determining whether the current time of the circuit to be detected generates an arc, a performance parameter value J corresponding to each sampling point in the current calculation period may be calculated according to formula (6)iThen, calculating the performance parameter value J corresponding to each sampling point in the current calculation periodiAnd finally, comparing the sum J 'with a preset performance parameter threshold value Jy according to the J', and judging whether the current moment of the circuit to be detected generates the electric arc or not according to a comparison result.
Wherein alpha ∈ (0,1), esIs a preset residual threshold. J. the design is a squareiInitial value of J0 is 0. When J' is not less than JyAnd if not, judging that the circuit to be detected does not generate the electric arc at the current moment.
In an embodiment of the present invention, when determining whether an arc fault occurs at the current time of the circuit to be detected according to the comparison result between J' and Jy, the value arc _ count of the arc counter may be updated by using a formula (7). When the arc _ count is larger than a preset arc number threshold value Cy, it is judged that the arc fault occurs at the current moment of the circuit to be detected, and when the arc _ count is smaller than or equal to the preset arc number threshold value Cy, it is judged that the arc fault does not occur at the current moment of the circuit to be detected.
It should be noted that, in the embodiment of the present invention, the ARMA model is taken as an example of a time domain load model, and a method for detecting the arc fault is described, but in a specific implementation, other time domain load models may also be used to detect the arc fault. When other time domain load models are used, reference may be made to the above description of the arc fault detection process, which is not further enumerated here.
Step 13, when the circuit to be detected has no arc fault, updating the parameters of the time domain load model according to the actual values of the electric signals of the sampling points at the current moment and the parameter update state of the time domain load model, including: the order and the coefficient.
In a specific implementation, when the circuit to be detected has no arc fault, for example, arc _ count is less than or equal to Cy, the parameter of the time-domain load model may be updated according to the actual value of the electrical signal at the current sampling point and the parameter update state of the time-domain load model.
In specific implementation, since the coefficient of the time domain load model is usually calculated according to the order of the time domain load model, when updating the parameter of the time domain load model, the order of the time domain load model may be updated according to the actual value of the electrical signal of the current time sampling point and the parameter update state of the time domain load model, and then the coefficient of the time domain load model may be updated according to the updated order of the time domain load model.
In an embodiment of the present invention, whether the circuit to be detected performs load switching at the current time and whether the time domain load model is in the parameter updating process may be respectively detected, and finally, the order of the time domain load model is updated according to the detection results of the parameter updating states of the circuit to be detected and the time domain load model. The electrical signal usually generates a corresponding transient pulse when the circuit to be detected is switched between loads. At the moment, the capacity of the time domain load model changing along with the electric signal can be improved by updating the order of the time domain load model, so that the detection precision of the arc fault is improved.
In specific implementation, whether the circuit to be detected performs load switching at the current moment can be detected according to the actual value of the electrical signal of the sampling point at the current moment. For example, the residual value e of the electrical signal at the current sampling pointtGreater than a predetermined maximum residual ehAnd if not, determining that the circuit to be detected does not carry out load switching at the current moment.
In a specific implementation, a first register may be preset, and the first register may store a value of the identification bit pf1 of whether the time-domain load model is in the parameter updating process. That is, each time the parameters of the time-domain load model are updated, the value of pf1 is modified accordingly. By reading the value of the first register, it can be detected whether the time-domain load model is in a parameter updating process. For example, pf1 may be set to 1 to identify that the time-domain load model is in the parameter update process, and pf1 may be set to 0 to identify that the time-domain load model is not in the parameter update process. When the value of the first register is read, if pf1 is equal to 1, it may be determined that the time-domain load model is in the parameter updating process, and if pf1 is equal to 0, it may be determined that the time-domain load model is not in the parameter updating process.
In specific implementation, according to the detection result of the parameter update state of the circuit to be detected and the time-domain load model, the order of the time-domain load model can be updated by various methods, and the details are not limited. The order of the time domain load model can be selected according to the convergence condition of the electric signal residual value of each sampling point, and the selected order can enable the electric signal residual value to be converged quickly.
In specific implementation, in order to further improve the detection accuracy of the arc fault and reduce the erroneous judgment, when the actual values of the electrical signals at all sampling points of the electrical signals in the current calculation period are not obtained, the parameters of the time-domain load model are updated according to the actual values of the electrical signals at the sampling points at the current moment and the parameter update state of the time-domain load model. For example, according to the sampling rate of the time domain load model, there should be 10 sampling points in the current calculation period, and if the sampling point at the current time is not the 10 th sampling point in the current calculation period, for example, the sampling point is the 5 th or 6 th sampling point, the parameter of the time domain load model may be updated according to the actual value of the electrical signal of the sampling point at the current time and the parameter update state of the time domain load model.
Referring to fig. 2, another arc fault detection method is provided in an embodiment of the present invention, which may include the following steps:
step 201, sampling an electrical signal of a circuit to be detected by using a preset time domain load model, and obtaining an electrical signal actual value x (t) of a sampling point of the electrical signal at the current moment.
Step 202, calculating the residual value e of the electrical signal of the sampling point in the current calculation period according to the actual value x (t) of the electrical signal of the sampling point in the current calculation periodt。
Step 203, calculating the performance parameter J of each sampling point in the current calculation periodi。
And 204, judging whether the actual values of the electric signals of all the sampling points of the electric signals in the current calculation period are obtained.
When the actual values of the electrical signals of all sampling points of the electrical signals in the current calculation period have been obtained, step 205 is executed, otherwise step 211 is executed.
Step 205, calculating the performance parameter J of each sampling point in the current calculation periodiThe sum J' of.
Step 206, judging the performance parameter J of each sampling point in the current calculation periodiIs greater than a preset performance parameter threshold Jy。
When J' > JyIf so, step 207 is performed, otherwise step 208 is performed.
In step 207, the arc number counter value arc _ count is incremented by 1.
In step 208, the arc number counter value arc _ count is decremented by 1.
Step 209, determine whether the value arc _ count of the arc number counter is greater than a preset arc number threshold Cy.
When arc _ count > Cy, step 210 is performed, otherwise step 211 is performed.
Step 210, determining that an arc fault has occurred.
Step 211, updating parameters of the time domain load model.
After updating the parameters of the time domain load model, step 201 is executed to continuously determine whether an arc fault occurs at the next moment.
For the steps 201 to 211, reference may be made to the above description of the steps 11 to 13, which is not described herein again.
Referring to fig. 3, an embodiment of the present invention provides a method for updating an order of the time-domain load model, where the method may include the following steps:
and step 31, judging whether the circuit to be detected is subjected to load switching at the current moment and whether the time domain load model is not in the parameter updating process.
For step 31, reference may be made to the above description of step 13, which is not described herein again.
And (3) when the circuit to be detected is subjected to load switching at the current moment and the time domain load model is not in the order updating process, executing the step 32, otherwise, executing the step 33.
Step 32, selecting the corresponding order, triggering the interrupt counter to start timing, and updating the value of the register.
In specific implementation, N orders can be preset, N is more than or equal to 2, and N is a positive integer. The N orders may be set according to the fitting capability of the time domain load model. In general, the minimum order of the N orders is a minimum of orders corresponding to data that can be fitted by using the time domain load model. The other of the N orders is typically greater than the minimum order. In addition, the value of N can be set by those skilled in the art according to actual conditions, and it can be understood that the larger the value of N, the higher the detection accuracy of the arc fault, and the larger the calculation amount in the arc fault detection process.
In a specific implementation, when the circuit to be detected performs load switching at the current time and the time domain load model is not in the parameter updating process, a corresponding order may be selected from N preset orders according to a preset rule as the order of the time domain load model, and the values of the first register and the second register are updated. Wherein the preset rule can be determined by those skilled in the art according to the convergence time of the residual value of the electrical signal in the current calculation cycle.
In an embodiment of the present invention, the preset rule may include: in the same order updating process, when the order of the time domain load model is updated for the 1 st time, the minimum order of the N orders is selected as the order of the time domain load model, and when the order of the time domain load model is updated for the 2 nd to N times, the selected orders are sequentially increased.
In a specific implementation, for example, the value pf1 of the first register is 1 to identify that the time-domain load model is in a parameter updating process, and pf1 is 0 to identify that the time-domain load model is not in a parameter updating process, the same order updating process is a process between two adjacent times of pf1 and 0. When the time-domain load model is in the parameter updating process, the value of pf1 changes from 0 to 1. When the parameter updating process of the time-domain load model is finished, the value of pf1 is changed from 1 to 0.
Taking N as 3, the orders are p1, p2 and p3, respectively, and p1 < p2 < p3 as an example, in the same order updating process, when the order of the time-domain load model is updated for the 1 st time, p1 is selected as the order of the time-domain load model. And when the order of the time domain load model is updated for the 2 nd time, selecting p2 as the order of the time domain load model. And when the order of the time domain load model is updated for the 3 rd time, selecting p3 as the order of the time domain load model.
In the same order updating process, when the order of the time domain load model is updated for the Nth time, the selected order is the maximum order of the N orders, and after the order of the time domain load model is updated for the Nth time, the order updating process is finished. Therefore, in the initial stage of the next parameter update, the order of the time-domain load model is the maximum order of the N orders, so that in the initial stage of each parameter update, the maximum order of the N orders can be selected as the initial order of the time-domain load model.
It should be noted that, in the specific implementation, other rules may also be used to update the order of the time domain load model, and the specific implementation is not limited as long as the convergence time of the electrical signal residual value of each sampling point in the current calculation period can be shortened.
In a specific implementation, the second register is adapted to store a value of an identification bit of a parameter update stage in which the time-domain load model is located in a current parameter update process. The number of the second registers may be only 1, or may be multiple, and is not particularly limited, as long as the parameter update stage where the time domain load model is located can be determined according to the value of the second register. For example, N-1 second registers may be set, and after the parameter of the time domain load model is updated each time, the value of the corresponding second register is updated, so that when the parameter of the time domain load model is updated next time, the parameter update stage of the time domain load model can be determined by reading the value of the second register.
In a specific implementation, after the parameters of the time-domain load model are updated each time, an interrupt timer may be triggered to start timing at the same time, so that when the parameters of the time-domain load model are updated next time, the parameter update stage where the time-domain load model is located may be determined more accurately. The time counted by the interrupt timer each time can be the same or different, and can be specifically set according to the time required by the circuit to be detected for load switching, the size of the N value and other factors.
And step 33, reading the value of the second register, and judging whether the order of the time domain load model is updated according to the value of the second register.
In a specific implementation, when the circuit to be detected is not switched to a load at the current time or the time-domain load model is in a parameter updating process, whether the order of the time-domain load model is updated or not can be determined by reading the value of the second register. For example, when N-1 registers are set, the 1 st second register may store the value of the flag bit for whether the 1 st update has been currently performed, the 2 nd second register may store the value of the flag bit for whether the 2 nd update has been currently performed, the 3 rd second register may store the value of the flag bit for whether the 3 rd update has been currently performed, … …, and the N-1 st second register may store the value of the flag bit for whether the N-1 st update has been currently performed.
When the parameters of the time-domain load model have been updated, step 34 is performed, otherwise step 35 is performed.
Step 34, reading the value of the interrupt timer, and determining whether the update time t of the latest order update reaches the preset time ts。
In a specific implementation, when it is determined that the parameter of the time-domain load model is updated according to the value of the second register, the value of the interrupt timer is read, so that the parameter update stage of the time-domain load model can be determined more accurately.
When it is most importantThe updating time t of the last order updating reaches the preset time tsThen, step 32 is executed, that is, according to the preset rule, a corresponding order is selected from the N orders as an order of the time domain load model, an interrupt timer is triggered to start timing, and a value of a corresponding register is updated. When the order of the time domain load model is updated for the Nth time, the register to be updated comprises the first register and the second register. And when the order of the time domain load model is updated for 2-N-1 times, the register to be updated only comprises a second register.
When the updating time length t of the latest order updating does not reach the preset time length tsThen step 35 is executed.
And step 35, keeping the current order of the time domain load model unchanged.
I.e. when the timing duration of the interrupt timer does not reach the preset duration tsAnd when the current order of the time domain load model is not updated.
Referring to fig. 4, an embodiment of the present invention provides another method for updating the order of the time-domain load model. In this embodiment, the time domain load model is an ARMA model. N is 3, the orders are p1, p2 and p3, respectively, and p1 < p2 < p 3. The data pf1 ═ 0 stored in the first register indicates that the time-domain load model is not in the parameter update process, and pf1 ═ 1 indicates that the time-domain load model is in the parameter update process. The 2 second registers store data pf2 and pf3 respectively. Wherein pf2 ═ 0 indicates that the time-domain load model has not been updated for the first time, and pf2 ═ 1 indicates that the time-domain load model has been updated for the first time. pf3 ═ 0 indicates that the time-domain load model has not been updated a second time, and pf2 ═ 1 indicates that the time-domain load model has been updated a second time. In the initial state, pf1, pf2 and pf3 were all 0.
The method may comprise the steps of:
step 401, determining the residual value e of the electrical signal at the sampling point at the current timetWhether or not it is greater than a preset valueMaximum residual value e ofhAnd determining whether the value of pf1 stored in the first register is 0.
When e ist＞ehAnd pf1 is 0, step 402 is performed, otherwise step 403 is performed.
Step 402, setting the order of the time domain load model to p1, triggering an interrupt timer to start timing, and updating pf1 to 1 and pf2 to 1.
At step 403, a determination is made as to whether pf2 is equal to 1.
When pf2 is 1, step 404 is executed, otherwise step 407 is executed.
Step 404, determining whether the timing duration t of the interrupt timer reaches a preset duration ts。
When t is equal to tsThen step 405 is performed, otherwise step 406 is performed.
Step 405, setting the order of the time domain load model to p2, triggering the interrupt timer to count again, and updating pf2 to 0 and pf3 to 1.
And step 406, keeping the current order of the time domain load model unchanged.
At step 407, a determination is made as to whether pf3 is equal to 1.
When pf3 is 1, step 408 is performed, otherwise step 410 is performed.
Step 408, judging whether the timing duration t of the interrupt timer reaches the preset duration t or nots。
When t is equal to tsIf so, step 409 is performed, otherwise step 406 is performed.
Step 409, setting the order of the time domain load model to p3, triggering the interrupt timer to count again, and updating pf3 to 0 and pf1 to 0.
Step 410, updating the coefficients of the time-domain load model.
It is to be noted thatIn one embodiment, after steps 405, 406, and 409 are performed, step 410 is performed. That is, no matter whether the parameters of the time domain load model are updated or not, when the time domain load model is used to judge whether the next time is failed or not, other coefficients of the time domain load model, including M, need to be updatedt TAnd phit。
The following further describes the application of the arc fault detection method in the embodiment of the present invention, taking the example of detecting whether the series current in the dehumidifier has the arc fault:
1) and setting the initial order p1 of the time-domain load model to be 8, and collecting the series current of the circuit where the load is located.
2) And (4) calculating the residual value of the electric signal corresponding to each sampling point from the initial sampling point, and judging whether the electric arc is generated at every half cycle. If the electric arcs are generated, adding 1 to the counter value of the number of the electric arcs; otherwise, the arc number counter value is decremented by 1 until it becomes 0.
3) And checking the counter value of the number of the electric arcs and judging whether the counter value exceeds a threshold value. If the threshold value is exceeded, setting the trip signal trip to 1, namely outputting an arc fault alarm signal; otherwise, entering a time domain load model variable-order process.
4) And when the value of the arc number counter does not exceed the threshold value, performing a variable order process on the time domain load model, namely comparing the residual value of the sampling point at the current moment with the maximum value of the preset residual, and updating the order of the time domain load model to p2 which is 4 or keeping the order p1 unchanged according to the comparison result.
Fig. 5 is a schematic diagram of residual convergence effects obtained by respectively using arc fault detection methods in the prior art and the embodiment of the present invention on a dehumidifier, that is, a comparison diagram of residual convergence effects of an ARMA model with a fixed order and an ARMA model with a variable order.
Fig. 5(a) shows the actual values of the current signals at the sampling points N obtained after sampling the series current I. Fig. 5(b) illustrates that when load switching occurs, an ARMA model with a fixed order is used to calculate a residual current value e1 at each sampling point N. Fig. 5(c) illustrates that the variable-order ARMA model is used to calculate the residual current e2 at each sampling point N when load switching occurs.
As can be seen by comparing fig. 5(b) and 5(c), when load switching occurs, the convergence rate of the current signal residual value e,2 using the variable-order ARMA model is faster than the convergence rate of the current signal residual value e1 using the fixed-order ARMA model, so that misjudgment of load switching as an arc fault can be avoided, and the arc fault detection accuracy can be improved.
As can be seen from the above, in the arc fault detection method in the embodiment of the present invention, when no arc fault occurs in the circuit to be detected, the order and the coefficient of the time domain load model are updated according to the actual value of the electrical signal of the sampling point at the current time and the parameter update state of the time domain load model, so that the convergence time of the residual value of the electrical signal of the sampling point in the current calculation period can be effectively shortened, the misjudgment of the arc fault is avoided, and the detection accuracy of the arc fault is improved.
In order to make the present invention better understood and realized by those skilled in the art, a detailed description is given below of a device corresponding to the above-described arc fault detection method.
Referring to fig. 6, an embodiment of the present invention provides an arc fault detection apparatus 60, and the apparatus 60 may include: a sampling unit 61, a calculating unit 62, a judging unit 63 and a first updating unit 64. Wherein:
the sampling unit 61 is adapted to sample an electrical signal of a circuit to be detected by using a preset time domain load model, and obtain an electrical signal actual value of a sampling point of the electrical signal at the current moment;
the calculating unit 62 is adapted to calculate an electrical signal residual value of a sampling point in the current calculating period according to an electrical signal actual value of the sampling point of the electrical signal in the current calculating period;
the judging unit 63 is adapted to judge whether the current moment of the circuit to be detected has an arc fault according to the residual value of the electrical signal at the sampling point of the current calculation period;
the first updating unit 64 is adapted to update the parameters of the time-domain load model according to the actual values of the electrical signals at the sampling points at the current time and the parameter updating state of the time-domain load model when the circuit to be detected has no arc fault, and includes: the sampling unit and the calculating unit sample and calculate the electric signal of the circuit to be detected again by adopting the updated time domain load model, and the judging unit judges whether the circuit to be detected has the arc fault at the next moment.
In a specific implementation, the determining unit 63 may include: a first judging sub-unit 631, and a second judging sub-unit 632. Wherein:
the first judging subunit 631 is adapted to judge whether the circuit to be detected generates an arc at the current moment according to the residual value of the electrical signal at the sampling point in the current calculation period;
the second judging subunit 632 is adapted to update the value of the arc counter according to the judgment result, and judge whether the arc fault occurs at the current time of the circuit to be detected according to the updated value of the arc counter.
In a specific implementation, the first updating unit 64 may include: a first update subunit 641 and a second update subunit 642. Wherein:
the first updating subunit 641 is adapted to update the order of the time-domain load model according to the actual value of the electrical signal of the current sampling point and the parameter updating state of the time-domain load model;
the second updating subunit 642 is adapted to update the coefficient of the time-domain load model according to the updated order of the time-domain load model.
In an embodiment of the present invention, the apparatus 60 may further include: a second updating unit 65. The second updating unit 65 is adapted to, when the actual values of the electrical signals at all sampling points of the electrical signals in the current calculation period are not obtained, update the parameters of the time-domain load model according to the actual values of the electrical signals at the sampling points at the current time and the parameter updating state of the time-domain load model.
In an embodiment of the present invention, referring to fig. 7, the first updating subunit 641 includes: a first detection module 71, a second detection module 72 and an update module 73. Wherein:
the first detection module 71 is adapted to detect whether the circuit to be detected performs load switching at the current moment according to the actual value of the electrical signal at the current moment sampling point;
the second detection module 72 is adapted to detect whether the time-domain load model is in a parameter updating process;
the updating module 73 is adapted to update the order of the time-domain load model according to the detection result of the parameter update state of the circuit to be detected and the time-domain load model.
In a specific implementation, the first detecting module 71 is adapted to determine that the circuit to be detected performs load switching at the current time when an electrical signal residual value of the electrical signal at a current time sampling point is greater than a preset maximum residual value, or determine that the circuit to be detected does not perform load switching at the current time.
In a specific implementation, the second detecting module 72 is adapted to read a value of a first register, and detect whether the time-domain load model is in a parameter updating process according to the read value of the first register, where the first register is adapted to store a value of an identification bit of whether the time-domain load model is in the parameter updating process.
In an embodiment of the present invention, the updating module 73 may include: a first update submodule 731. The first updating sub-module 731 is adapted to select a corresponding order from N preset orders according to a preset rule as the order of the time domain load model when the circuit to be detected performs load switching at the current time and the time domain load model is not in the parameter updating process, and update the values of the first register and the second register. The second register is suitable for storing the value of the identification bit of the parameter updating stage where the time domain load model is located in the current parameter updating process, wherein N is more than or equal to 2 and is a positive integer.
In an embodiment of the present invention, the updating module 73 may further include: a first read sub-module 732, a second read sub-module 733, and a first processing sub-module 734. Wherein:
the first reading sub-module 732 is adapted to read a value of a second register when the circuit to be detected is not switched in load at the current time or the time-domain load model is in a parameter updating process, and determine whether the order of the time-domain load model is updated according to the value of the second register;
the second reading sub-module 733, configured to, when it is determined that the parameter of the time-domain load model has been updated, read the value of the interrupt timer, and determine whether the update duration of the latest order update reaches a preset duration;
the first processing sub-module 734 is adapted to, when the update duration of the last order update reaches a preset duration, select a corresponding order from the N orders as the order of the time domain load model according to the preset rule, trigger an interrupt timer to start timing, and update the value of the corresponding register.
In an embodiment of the present invention, the preset rule includes: in the same parameter updating process, when the order of the time domain load model is updated for the 1 st time, the minimum order of the N orders is selected as the order of the time domain load model, and when the order of the time domain load model is updated for the 2 nd to N times, the selected orders are sequentially increased.
In a specific implementation, the updating module 73 may further include: a second processing sub-module 735. The second processing sub-module 735 is adapted to, when it is determined that the order of the time-domain load model is not updated according to the value of the second register, keep the current order of the time-domain load model unchanged.
In a specific implementation, the updating module 73 may further include: the third processing sub-module 736 is adapted to keep the current order of the time-domain load model unchanged when the update duration of the latest order update does not reach the preset duration.
In a specific implementation, the time domain loading model is an ARMA model.
In a specific implementation, the electrical signal is a voltage signal or a current signal.
Those skilled in the art will appreciate that all or part of the steps in the methods of the above embodiments may be implemented by associated hardware instructed by a program, which may be stored in a computer-readable storage medium, and the storage medium may include: ROM, RAM, magnetic or optical disks, and the like.
Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (28)

1. A method of detecting an arc fault, comprising:
sampling an electric signal of a circuit to be detected by adopting a preset time domain load model to obtain an electric signal actual value of the electric signal at a sampling point at the current moment, and calculating an electric signal residual value of the sampling point in the current calculation period according to the electric signal actual value of the sampling point of the electric signal in the current calculation period;
judging whether the current moment of the circuit to be detected has an arc fault according to the residual value of the electric signal of the sampling point of the current calculation period;
when the circuit to be detected has no arc fault, updating the parameters of the time domain load model according to the actual values of the electric signals of the sampling points at the current moment and the parameter updating state of the time domain load model, wherein the updating state comprises the following steps: the order and coefficient;
and sampling the electric signal of the circuit to be detected again by adopting the updated time domain load model, and judging whether the circuit to be detected has an arc fault at the next moment.
2. The method for detecting arc faults as claimed in claim 1, wherein the determining whether the arc fault occurs at the current moment of the circuit to be detected according to the residual value of the electrical signal at the sampling point in the current calculation period includes:
judging whether the current moment of the circuit to be detected generates an electric arc or not according to the residual value of the electric signal of the sampling point in the current calculation period;
and updating the value of the arc counter according to the judgment result, and judging whether the current moment of the circuit to be detected has the arc fault according to the updated value of the arc counter.
3. The method for detecting arc faults as claimed in claim 1, wherein the updating the parameters of the time-domain load model according to the actual values of the electrical signals at the sampling points at the current time and the parameter updating states of the time-domain load model includes:
updating the order of the time domain load model according to the actual value of the electric signal of the sampling point at the current moment and the parameter updating state of the time domain load model;
and updating the coefficient of the time domain load model according to the updated order of the time domain load model.
4. The method according to claim 3, wherein the updating the order of the time-domain load model according to the actual value of the electrical signal at the current time sampling point and the parameter updating state of the time-domain load model comprises:
detecting whether the circuit to be detected carries out load switching at the current moment according to the actual value of the electric signal of the sampling point at the current moment;
detecting whether the time domain load model is in a parameter updating process;
and updating the order of the time domain load model according to the detection results of the parameter updating states of the circuit to be detected and the time domain load model.
5. The arc fault detection method of claim 4, wherein said detecting whether the circuit under test is performing a load switch at a current time comprises:
and when the residual value of the electric signal at the sampling point of the current moment is larger than the preset maximum residual value, determining that the circuit to be detected performs load switching at the current moment, otherwise, determining that the circuit to be detected does not perform load switching at the current moment.
6. The method of arc fault detection according to claim 4, wherein said detecting whether said time-domain load model is in a parameter update process comprises:
and reading the value of a first register, and detecting whether the time domain load model is in the parameter updating process according to the read value of the first register, wherein the first register is suitable for storing the value of the identification bit of whether the time domain load model is in the parameter updating process.
7. The arc fault detection method of claim 6, wherein updating the order of the time-domain load model according to the detection result of the parameter update status of the circuit under test and the time-domain load model comprises:
when the circuit to be detected is subjected to load switching at the current moment and the time domain load model is not in the parameter updating process, selecting a corresponding order from N preset orders as the order of the time domain load model according to a preset rule, triggering an interrupt timer to start timing, and updating the values of a first register and a second register; the second register is suitable for storing the value of the identification bit of the parameter updating stage where the time domain load model is located in the current parameter updating process, wherein N is more than or equal to 2 and is a positive integer.
8. The method according to claim 7, wherein the updating the order of the time-domain load model according to the detection result of the parameter update status of the circuit under test and the time-domain load model further comprises:
when the circuit to be detected is not subjected to load switching at the current moment or the time domain load model is in the parameter updating process, reading the value of the second register, and determining whether the order of the time domain load model is updated or not according to the value of the second register;
when the order of the time domain load model is determined to be updated, reading the value of the interrupt timer, and determining whether the updating time length of the latest order updating reaches the preset time length;
and when the updating time length of the latest order updating reaches a preset time length, selecting a corresponding order from the N orders as the order of the time domain load model according to the preset rule, triggering an interrupt timer to start timing, and updating the value of a corresponding register.
9. The method of arc fault detection according to claim 8, wherein said preset rules comprise:
in the same parameter updating process, when the order of the time domain load model is updated for the 1 st time, the minimum order of the N orders is selected as the order of the time domain load model, and when the order of the time domain load model is updated for the 2 nd to N times, the selected orders are sequentially increased.
10. The method according to claim 8, wherein the updating the order of the time-domain load model according to the detection result of the parameter update status of the circuit under test and the time-domain load model further comprises:
and when the order of the time domain load model is determined to be not updated according to the value of the second register, keeping the current order of the time domain load model unchanged.
11. The method according to claim 8, wherein the updating the order of the time-domain load model according to the detection result of the parameter update status of the circuit under test and the time-domain load model further comprises:
and when the updating time length of the latest order updating does not reach the preset time length, keeping the current order of the time domain load model unchanged.
12. The method of detecting an arc fault of claim 1, further comprising:
when the actual values of the electric signals of all sampling points of the electric signals in the current calculation period are not obtained, updating the order and the coefficient of the time domain load model according to the actual values of the electric signals of the sampling points at the current moment and the parameter updating state of the time domain load model, and judging whether the circuit to be detected has the arc fault at the next moment according to the updated time domain load model.
13. The method of arc fault detection according to claim 1, wherein the time domain load model is an ARMA model.
14. The method of arc fault detection according to claim 1, wherein said electrical signal is a voltage signal or a current signal.
15. An arc fault detection device, comprising:
the sampling unit is suitable for sampling the electric signal of the circuit to be detected by adopting a preset time domain load model to obtain the actual value of the electric signal of the sampling point of the electric signal at the current moment;
the computing unit is suitable for computing the residual value of the electric signal of the sampling point in the current computing period according to the actual value of the electric signal of the sampling point of the electric signal in the current computing period;
the judging unit is suitable for judging whether the current moment of the circuit to be detected has an arc fault according to the residual value of the electric signal of the sampling point of the current calculation period;
the first updating unit is suitable for updating the parameters of the time domain load model according to the actual values of the electric signals of the sampling points at the current moment and the parameter updating state of the time domain load model when the circuit to be detected has no arc fault, and comprises the following steps: the sampling unit and the calculating unit sample and calculate the electric signal of the circuit to be detected again by adopting the updated time domain load model, and the judging unit judges whether the circuit to be detected has the arc fault at the next moment.
16. The arc fault detection device of claim 15, wherein the judging unit comprises:
the first judgment subunit is suitable for judging whether the current moment of the circuit to be detected generates electric arcs according to the electric signal residual value of the sampling point in the current calculation period;
and the second judgment subunit is suitable for updating the value of the arc counter according to the judgment result and judging whether the current moment of the circuit to be detected has the arc fault according to the updated value of the arc counter.
17. The arc fault detection device of claim 15, wherein the first updating unit comprises:
the first updating subunit is suitable for updating the order of the time domain load model according to the actual value of the electric signal of the current sampling point and the parameter updating state of the time domain load model;
and the second updating subunit is suitable for updating the coefficient of the time domain load model according to the updated order of the time domain load model.
18. The arc fault detection device of claim 17, wherein the first update subunit comprises:
the first detection module is suitable for detecting whether the circuit to be detected carries out load switching at the current moment according to the actual value of the electric signal of the sampling point at the current moment;
the second detection module is suitable for detecting whether the time domain load model is in a parameter updating process;
and the updating module is suitable for updating the order of the time domain load model according to the detection results of the parameter updating states of the circuit to be detected and the time domain load model.
19. The arc fault detection device according to claim 18, wherein the first detection module is adapted to determine that the circuit to be detected performs load switching at the current time when the residual value of the electrical signal at the current time sampling point is greater than a preset maximum residual value, and otherwise determine that the circuit to be detected does not perform load switching at the current time.
20. The arc fault detection device of claim 18, wherein the second detection module is adapted to read a value of a first register and detect whether the time-domain load model is in a parameter update process according to the read value of the first register, and the first register is adapted to store a value of an identification bit of whether the time-domain load model is in the parameter update process.
21. The arc fault detection device of claim 20, wherein the update module comprises:
the first updating submodule is suitable for selecting a corresponding order from N preset orders as the order of the time domain load model according to a preset rule when the load of the circuit to be detected is switched at the current moment and the time domain load model is not in the parameter updating process, triggering an interrupt timer to start timing and updating the values of the first register and the second register; the second register is suitable for storing the value of the identification bit of the parameter updating stage where the time domain load model is located in the current parameter updating process, wherein N is more than or equal to 2 and is a positive integer.
22. The arc fault detection device of claim 21, wherein the update module further comprises:
the first reading submodule is suitable for reading the value of the second register when the circuit to be detected is not subjected to load switching at the current moment or the time domain load model is in a parameter updating process, and determining whether the order of the time domain load model is updated or not according to the value of the second register;
the second reading submodule is suitable for reading the value of the interrupt timer when the order of the time domain load model is determined to be updated, and determining whether the updating time length of the latest order updating reaches the preset time length;
and the first processing submodule is suitable for selecting a corresponding order from the N orders as the order of the time domain load model according to the preset rule when the updating time length of the latest order updating reaches the preset time length, triggering an interrupt timer to start timing and updating the value of a corresponding register.
23. The arc fault detection device of claim 22, wherein the preset rules comprise:
in the same parameter updating process, when the order of the time domain load model is updated for the 1 st time, the minimum order of the N orders is selected as the order of the time domain load model, and when the order of the time domain load model is updated for the 2 nd to N times, the selected orders are sequentially increased.
24. The arc fault detection device of claim 22, wherein the update module further comprises:
and the second processing submodule is suitable for keeping the current order of the time domain load model unchanged when the order of the time domain load model is determined not to be updated according to the value of the second register.
25. The arc fault detection device of claim 22, wherein the update module further comprises:
and the third processing submodule is suitable for keeping the current order of the time domain load model unchanged when the updating time length of the latest order updating does not reach the preset time length.
26. The arc fault detection device of claim 15, further comprising: and the second updating unit is suitable for updating the order and the coefficient of the time domain load model according to the electric signal actual value of the sampling point at the current moment and the parameter updating state of the time domain load model when the electric signal actual values of all the sampling points of the electric signal in the current computing period are not obtained, so as to judge whether the circuit to be detected has the arc fault at the next moment according to the updated time domain load model.
27. The arc fault detection device of claim 15, wherein the time domain load model is an ARMA model.
28. The arc fault detection device of claim 15, wherein the electrical signal is a voltage signal or a current signal.
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