CN114636883A - Alternating current based power system fault determination method and device and storage medium - Google Patents
Alternating current based power system fault determination method and device and storage medium Download PDFInfo
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Abstract
The invention discloses a method, a device and a storage medium for determining faults of a power system based on alternating current, wherein the method comprises the following steps: determining the acquisition interval of the alternating current quantity sampling points according to the period of the alternating current quantity periodic wave; acquiring alternating current of a first preset number of sampling points based on the acquisition interval, and calculating according to a full-wave Fourier algorithm to obtain a plurality of first alternating current effective values; determining whether the alternating current quantity has a signal mutation point based on the relation among the plurality of first alternating current quantity effective values; when the signal mutation point exists, continuously acquiring the alternating current quantity of a second preset number of sampling points based on the acquisition interval, and calculating according to a half-wave Fourier algorithm to obtain a second alternating current quantity effective value; and determining whether the power system has faults or not based on the relationship between the second alternating current quantity effective value and the preset effective value. Therefore, the method provides a more accurate fault judgment method when the operation data exceeds the limit value from the aspect of customer through the signal catastrophe point and the two judgments with the preset effective value.
Description
Technical Field
The invention relates to the technical field of electronics, in particular to a method and a device for determining a power system fault based on an alternating current and a storage medium.
Background
In recent years, in a 10-35 kV medium-voltage power distribution network of a power system, with the rapid increase of electric loads, the power distribution network is increasingly complex, and the installation number of intelligent equipment is rapidly increased.
Because the requirements of power users on the stability and reliability of power supply are further improved, in the existing power distribution network relay protection method, the method with high sensitivity is too simple, is easy to be interfered, is misjudged and has low accuracy, the method with high accuracy is too complex, and tripping processing is not easy to be performed in time. Therefore, the relay protection device is required to accurately judge the operation state change of the power equipment, and when the operation data exceeds the limit value, the trip processing can be rapidly and accurately carried out, so that the power supply reliability of the power system is guaranteed.
Disclosure of Invention
In view of this, the present invention provides a method, an apparatus, and a storage medium for determining a fault of an electric power system based on an ac traffic, so as to solve the problem that the fault cannot be accurately determined when a fault occurs in a protected object.
The technical scheme provided by the invention is as follows:
a first aspect of an embodiment of the present invention provides a method for determining a fault of an electric power system based on an ac traffic, including: determining the acquisition interval of the alternating current quantity sampling points according to the period of the alternating current quantity periodic wave; acquiring alternating current of a first preset number of sampling points based on the acquisition interval, and calculating according to a full-wave Fourier algorithm to obtain a plurality of first alternating current effective values; determining whether the alternating current quantity has a signal mutation point based on the relation among the plurality of first alternating current quantity effective values; and when the signal mutation point exists, continuously acquiring the alternating current quantity of a second preset number of sampling points based on the acquisition interval, and calculating to obtain a second alternating current quantity effective value according to a half-wave Fourier algorithm.
Optionally, determining an acquisition interval of the ac traffic sampling point according to a cycle of the ac traffic cycle includes: collecting the frequency of each cycle of the alternating current; determining the period of the next cycle according to the frequency change rate obtained by calculating the frequency of each cycle and the frequency of the current power system; and determining the acquisition interval of the alternating flow sampling points according to the period and the third preset number.
Optionally, the acquiring an alternating current amount of a first preset number of sampling points based on the collecting interval, and calculating according to a full-wave fourier algorithm to obtain a plurality of first alternating current amount effective values, includes: acquiring the alternating current quantity of a first preset number of sampling points based on the acquisition interval, and calculating to obtain a first alternating current quantity effective value at a first time according to a full-wave Fourier algorithm; and continuously acquiring the alternating current of the first preset number of sampling points based on the acquisition interval, and calculating to obtain a first alternating current effective value at a second time according to a full-wave Fourier algorithm.
Optionally, determining whether the traffic volume has a signal discontinuity based on a relationship between the plurality of first traffic volume effective values includes: judging the relation between the first alternating current quantity effective value at the second time and the first alternating current quantity effective value at the first time of a first preset multiple; and when the first alternating current quantity effective value at the second time is larger than the first alternating current quantity effective value at the first time of a first preset multiple, determining that a signal mutation point exists in the alternating current quantity.
Optionally, before continuing to acquire the ac quantity of the second preset number of sampling points based on the collection interval, the method further includes: when signal catastrophe points exist, continuously acquiring the alternating current of a first preset number of sampling points based on the acquisition interval, and calculating to obtain a first alternating current effective value at a third time according to a full-wave Fourier algorithm; judging the relation between the first alternating current quantity effective value at the third time and the first alternating current quantity effective value at the second time of a second preset multiple; and when the first alternating current quantity effective value at the third time and the first alternating current quantity effective value at the second time of a second preset multiple are obtained, determining that a signal mutation point exists in the alternating current quantity.
Optionally, the alternating current quantity includes a multi-channel voltage alternating current quantity, a multi-channel current alternating current quantity, and a multi-channel power alternating current quantity; determining whether the power system has a fault based on the relationship between the second alternating current quantity effective value and the preset effective value, wherein the method comprises the following steps: and when any two channel alternating current quantity effective values in the voltage alternating current quantity effective value, the current alternating current quantity effective value and the power alternating current quantity effective value are larger than a preset effective value of a third preset multiple, determining that the power system has a fault.
Optionally, the method for determining a fault of an electric power system based on an alternating current amount further includes: when the power system is determined to have a fault, a tripping instruction is sent out; judging whether a switch of an object to be protected is tripped after preset time; if the tripping operation is not carried out, a tripping instruction is continuously sent out; and if the power system is tripped, uploading the fault existing in the power system to the power monitoring system.
A second aspect of the embodiments of the present invention provides an apparatus for determining a fault of an electric power system based on an ac traffic, including: the data processing module is used for determining the acquisition interval of the alternating current quantity sampling points according to the period of the alternating current quantity periodic wave; the data acquisition module is used for acquiring alternating current quantity frequency and obtaining alternating current quantity of a first preset number of sampling points based on the acquisition interval, and calculating to obtain a plurality of first alternating current quantity effective values according to a full-wave Fourier algorithm; the data judgment module is used for determining whether the alternating current quantity has signal mutation points or not based on the relation among the plurality of first alternating current quantity effective values; the information communication module is used for continuously acquiring the alternating current quantity of a second preset number of sampling points based on the acquisition interval when the signal mutation points exist, and calculating to obtain a second alternating current quantity effective value according to a half-wave Fourier algorithm; and the judging and monitoring module is used for determining whether the power system has faults or not based on the relationship between the second alternating current effective value and the preset effective value.
A third aspect of the embodiments of the present invention provides a computer-readable storage medium, where computer instructions are stored, where the computer instructions are configured to cause a computer to execute the method for determining a fault of an electric power system based on an alternating current amount according to any one of the first aspect and the first aspect of the embodiments of the present invention.
A fourth aspect of an embodiment of the present invention provides an electronic device, including: the power system fault determination method based on the alternating current amount comprises a memory and a processor, wherein the memory and the processor are connected in a communication mode, the memory stores computer instructions, and the processor executes the computer instructions so as to execute the power system fault determination method based on the alternating current amount according to the first aspect and any one of the first aspect of the embodiments of the invention.
The technical scheme provided by the invention has the following effects:
according to the method, the device and the storage medium for determining the fault of the power system based on the alternating current, the multiple first alternating current effective values are obtained through calculation according to a full-wave Fourier algorithm, whether the alternating current has a signal mutation point or not is determined according to the relation between the multiple first alternating current effective values, when the signal mutation point exists, the alternating current of the second preset number of sampling points is continuously obtained based on the acquisition interval, the second alternating current effective value is obtained through calculation according to the half-wave Fourier algorithm, and whether the fault exists in the power system is determined based on the relation between the second alternating current effective value and the preset effective value. Therefore, the method provides a more accurate fault judgment method when the operation data exceeds the limit value from the aspect of customer through the signal catastrophe point and the two judgments with the preset effective value.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a flow chart of a method of determining a fault in an electrical power system based on an amount of alternating current in accordance with an embodiment of the present invention;
FIG. 2 is a flow chart of a method of determining a fault in an electrical power system based on an amount of alternating current in accordance with another embodiment of the present invention;
FIG. 3 is a flow chart of a method of determining a fault in an electrical power system based on an amount of alternating current in accordance with another embodiment of the present invention;
FIG. 4 is a flow chart of a method of determining a fault in an electrical power system based on an amount of alternating current in accordance with another embodiment of the present invention;
FIG. 5 is a flow chart of a method of determining a fault in an electrical power system based on an amount of alternating current in accordance with another embodiment of the present invention;
fig. 6 is a block diagram of a structure of an ac flow-based power system fault determination apparatus according to an embodiment of the present invention;
FIG. 7 is a schematic structural diagram of a computer-readable storage medium provided in accordance with an embodiment of the present invention;
fig. 8 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The embodiment of the invention provides a power system fault determination method based on alternating current, which comprises the following steps as shown in figure 1:
step S101: determining the collection interval of the alternating current quantity sampling points according to the period of the alternating current quantity periodic wave; specifically, the ac amount includes a voltage ac amount, a current ac amount, a power ac amount, and the like. The cycle represents a wave of one cycle of the alternating current quantity, the sampling points of the alternating current quantity are positions for selecting sampling in the cycle of the alternating current quantity, the number of the sampling points of the alternating current quantity is not limited, and for example, the number of the sampling points can be 8, 16 and the like. The sampling interval is the time interval between sampling points at intervals, the interval of the sampling points can be determined according to the period of the periodic wave and the number of the sampling points, the alternating flow is assumed to be stable, the interval of the sampling points is the same as long as the number of the sampling points is unchanged, if the alternating flow is unstable, the period is changed, the number of the sampling points is unchanged, and the interval of the sampling points is different.
Step S102: acquiring alternating current of a first preset number of sampling points based on the acquisition interval, and calculating to obtain a plurality of first alternating current effective values according to a full-wave Fourier algorithm; specifically, the first preset number is the number of the first type of sampling points selected for calculating the effective value of the alternating current quantity, and may be selected according to the total number of sampling points and the actual situation, the value of the first preset number is not limited, and may be, for example, 2, 3, 4, and the like, and the first effective value of the alternating current quantity is the effective value calculated by the full-wave fourier algorithm on the alternating current quantity of the sampling points of the first preset number. The full-wave fourier algorithm adopts the following formula:
wherein X*.RThe real part of a full-wave Fourier of the AC flow, X*.SThe imaginary part, X, of a full-wave Fourier of the alternating flow*The amplitude of the full-wave fourier of the alternating flow is shown, N is the number of points sampled per wave, x (k) is the sample value when k is N-N +1, and N is the current sample point.
Specifically, assume that the selected AC current is current, X*.RThe real part of a full-wave Fourier of the AC flow, X*.SThe imaginary part, X, of a full-wave Fourier of the alternating flow*The amplitude of the full-wave fourier of the alternating flow is shown, N is the number of points sampled per wave, x (k) is the sample value when k is N-N +1, and N is the current sample point.
The real part and the imaginary part of the full-wave Fourier of the alternating flow can be calculated by using a full-wave Fourier algorithm, the first alternating-current quantity effective value is an effective value calculated by aiming at the alternating-current quantity of the selected first preset number of sampling points, and the first alternating-current quantity effective value can be obtained according to the real part and the imaginary part of the full-wave Fourier of the alternating flow of the first preset number of sampling points. And continuously selecting the alternating current quantities of the first preset number of sampling points to calculate a second first alternating current quantity effective value, wherein a plurality of first alternating current quantity effective values can be obtained through analogy, and therefore, the effective value calculated by the first preset number of sampling points adopts the following formula:
wherein, XtRepresenting the significance calculated from the first predetermined number of sample points,
the real part of the full-wave Fourier of the selected first preset number of sampling points of the alternating current quantity is shown,
and the imaginary part of the full-wave Fourier of the selected first preset number of the alternating current quantity sampling points is represented. For the collected multiple groups of first preset number sampling points, the calculation can be carried out according to the formula, and the first alternating current quantity effective value corresponding to each group of first preset number sampling points is determined, so that multiple first alternating current quantity effective values are obtained.
Step S103: determining whether the alternating current quantity has a signal mutation point based on the relation among the plurality of first alternating current quantity effective values; specifically, the relationship between the plurality of first effective values of the alternating current amount is directed to a numerical value magnitude relationship. Judging the relationship between the plurality of first ac value may determine whether the ac flow has a signal discontinuity, in an embodiment, assuming that there are two first ac value collected and calculated according to a time sequence, judging the relationship between the plurality of first ac value includes: and judging whether the effective value of the first alternating current quantity at the second time is greater than a certain multiple of the effective value of the first alternating current quantity at the first time, and determining that a signal catastrophe point exists when the effective value of the first alternating current quantity at the second time is greater than the effective value of the first alternating current quantity at the first time, wherein the multiple can be selected according to actual conditions, such as 0.5, 3, 4 and the like. When less than, step S101 may be re-executed.
Step S104: when the signal mutation point exists, continuously acquiring the alternating current quantity of a second preset number of sampling points based on the acquisition interval, and calculating according to a half-wave Fourier algorithm to obtain a second alternating current quantity effective value; specifically, when it is determined in step S103 that the signal discontinuity point exists, the alternating current amount of the second preset number of sampling points needs to be continuously obtained based on the acquisition interval, and then the second alternating current amount effective value is obtained by calculating using a half-wave fourier algorithm, where the second preset number is the number of sampling points selected for calculating the second alternating current amount effective value, and the second preset number may be different from the first preset number. The half-wave fourier algorithm adopts the following formula:
wherein, X'*.RReal part of half-wave Fourier representing alternating flow, X'*.SRepresenting the imaginary part, X ', of a half-wave Fourier of the alternating flow'*The amplitude of the half-wave fourier of the alternating current is shown, N/2 is the number of points sampled per cycle, x (k) is the sample value when k is N-N/2 +1, and N is the current sample point.
Specifically, assume the select alternating current is current, X'*.RRepresenting the real part of the half-wave Fourier of the current, X'*S denotes the imaginary part of the half-wave Fourier of the current, X'*Denotes the amplitude of the current in the form of a half-wave fourier, N/2 denotes the number of points sampled per cycle, x (k) denotes the sample value at which k is N-N/2 +1, and N denotes the current sample point.
The second effective value of the alternating current quantity may be calculated by combining the half-wave fourier transform, and the calculation is performed by analogy with the formula for calculating the first effective value of the alternating current quantity in step S102, which is not described herein again.
Step S105: and determining whether the power system has faults or not based on the relationship between the second alternating current quantity effective value and the preset effective value. Specifically, the relationship between the second ac value and the preset effective value is a numerical value size relationship. And judging the relationship between the second alternating current quantity effective value and the preset effective value to determine whether the power system has faults or not, and determining that the faults exist when the second alternating current quantity effective value is greater than a certain multiple of the preset effective value, wherein the preset effective value and the multiple can be selected according to actual conditions. And re-executing the step S101 when the second ac value is less than or equal to the preset effective value.
According to the method for determining the fault of the power system based on the alternating current, provided by the embodiment of the invention, through collecting multi-channel alternating current data, each channel calculates the effective value of the alternating current for multiple times, firstly, the relation between the effective values is judged, and then, the relation between the finally calculated effective value and the preset effective value is judged to determine whether the power system has the fault. The method considers the alternating current quantities of different sampling channels, and simultaneously judges the relationship between the effective values and the preset effective value for a plurality of times, so that the method provides a more accurate fault judgment method when the operation data exceeds the limit value objectively through the signal catastrophe point and the two judgments of the effective value and the preset effective value. Therefore, the power system fault determination method based on the alternating current amount can better maintain the stability of the power system.
In one embodiment, as shown in fig. 2, the step of determining the sampling interval of the ac current sampling points according to the period of the ac current cycle may be as follows:
step S201: collecting the frequency of each cycle of the alternating current; in an embodiment, a frequency measurement circuit may be used to collect the frequency of each cycle of the ac power, where the frequency measurement circuit is not limited and may be selected according to actual situations.
Step S202: determining the period of the next cycle according to the frequency change rate obtained by calculating the frequency of each cycle and the frequency of the current power system; in an embodiment, assuming that the collection time is T, the frequency of the current power system, i.e. the frequency of the first collected cycle is Fo, and the frequency of the last collected cycle is Fp, an expression Fp + td/dt can be obtained, according to which the frequency change rate df/dt can be calculated, according to 1/T1＝Fp+T1The df/dt calculates the period T of the next cycle1。
Step S203: determining the collection interval of the alternating flow sampling points according to the period and the third preset number; in one embodiment, according to T1And a third preset number c to obtain a next sampling time interval T1And c, the ratio of the total weight to the total weight of the product. The third preset number can be larger than the first preset number and the second preset number。
In an embodiment, as shown in fig. 3, the alternating current of a first preset number of sampling points is obtained based on the collection interval, and a plurality of first alternating current effective values are obtained through calculation according to a full-wave fourier algorithm; determining whether the signal discontinuity point exists in the alternating current quantity based on the relationship between the plurality of first alternating current quantity effective values may be according to the following steps:
step S301: acquiring the alternating current of a first preset number of sampling points based on the acquisition interval, and calculating to obtain a first alternating current effective value at a first time according to a full-wave Fourier algorithm; in a specific embodiment, assuming that the third predetermined number is 32, the first predetermined number is 3, the frequency of the collected periodic wave is 50Hz, the period can be calculated to be 0.02 sec, the collection time interval is 0.000625 sec, the ac flow of the first predetermined number at the first time is collected according to the time interval, the real part and the imaginary part of the full-wave fourier of the ac flow are calculated by using a full-wave fourier algorithm, and then the first ac flow effective value X at the first time is calculated by using the calculation average effective value formula0。
Step S302: continuously acquiring the alternating current of a first preset number of sampling points based on the acquisition interval, and calculating to obtain a first alternating current effective value X at a second time according to a full-wave Fourier algorithm1(ii) a Collecting a first preset number of alternating current flows at a second time according to the sampling time interval in the step S301, calculating a corresponding real part and an imaginary part of a full-wave Fourier through the alternating current flows by utilizing a full-wave Fourier algorithm, and then calculating a first alternating current effective value X at the second time by utilizing a calculation average effective value formula1. The second time may be a time next to the first time.
Step S303: determining whether the alternating current quantity has a signal mutation point based on the relation among the plurality of first alternating current quantity effective values; specifically, the effective value X of the first alternating current amount at the second time needs to be determined first1And a first AC effective value X of a first preset multiple at a first time0The second time is the time for collecting the second predetermined number of sampling points, and in one embodiment, the effective value X of the first ac quantity at the second time is1Less than or equal to the first preset multipleA first time effective value X of the alternating current0Then, from step S101, the first effective value X of the AC amount at the second time is started again1First AC value X of first time larger than first preset multiple0And then, preliminarily judging the existence of signal mutation points in the collected quantity.
In order to make the judgment more accurate, when the signal catastrophe point exists, the alternating current of the first preset number of sampling points can be continuously acquired based on the acquisition interval, and the first alternating current effective value X at the third time is calculated according to the full-wave Fourier algorithm2(ii) a Judging the effective value X of the first alternating current quantity at the third time2And a second preset multiple of the effective value X of the first alternating current quantity at a second time1The relationship between; when the first AC value X of the third time is the effective value X2And a second preset multiple of the effective value X of the first alternating current quantity at a second time1And then determining that the alternating current quantity has a signal mutation point. Specifically, the full-wave fourier algorithm may be used to calculate the real part and the imaginary part of the full-wave fourier from the ac quantity at the third time, and then the mean effective value formula is used to calculate the effective value X of the first ac quantity at the third time2Then, the effective value X of the first AC quantity at the third time is judged2And a second preset multiple of the effective value X of the first alternating current quantity at a second time1The effective value X of the first alternating current quantity at the third time2The effective value X of the first alternating current quantity at the second time which is greater than the second preset multiple1If so, confirming that the traffic has a signal discontinuity point, executing step S104, otherwise, restarting from step S101.
In an embodiment, when it is determined in step S103 that the signal discontinuity point exists, the second effective value X of the alternating current quantity is determined3And a third preset multiple of the preset effective value Zn, wherein the relation between the second preset multiple and the third preset multiple can determine whether the power system has a fault, in a specific embodiment, the real part and the imaginary part of the alternating current flow are calculated by the alternating current quantity of the second preset number of sampling points by using a half-wave Fourier algorithm, and then the effective value X of the second alternating current quantity is calculated3. Comparing the second AC value X3And a third preset multiple relation of the preset effective value Zn when the second alternating current quantity effective value X3And when the sampling channel AC effective value is larger than a third preset multiple of the preset effective value Zn, judging that the sampling channel AC effective value is out of limit.
The steps S101 to S105 executed in a power system may be implemented to synchronously monitor a plurality of sampling channels (including different channels with the same ac flow rate and different channels with different ac flow rates), and when any two of the voltage ac quantity effective value, the current ac quantity effective value, and the power ac quantity effective value are greater than a preset effective value of a third preset multiple, determine that the power system has a fault, and determine that the protected object is in a fault state. And when the second alternating current effective value is smaller than or equal to a third preset multiple of the preset effective value, the step S101 is restarted.
As an alternative implementation manner of the embodiment of the present invention, as shown in fig. 4, when it is determined that the power system has a fault, it is necessary to detect whether the switch of the protection object is tripped and perform processing. In one embodiment, the following process may be implemented: when the power system is determined to have a fault, a tripping instruction is sent out; judging whether a switch of an object to be protected is tripped after preset time; if the tripping operation is not carried out, a tripping instruction is continuously sent out; and if the power system is tripped, uploading the fault existing in the power system to the power monitoring system.
According to the method for determining the fault of the power system based on the alternating current, provided by the embodiment of the invention, the effective value of the alternating current is calculated by adopting the full-wave Fourier algorithm and the half-wave Fourier algorithm, and the fault is determined by multi-channel sampling, so that the out-of-limit determination of two or more channels is met, the misjudgment caused by interference is avoided, the accuracy is improved, and the speed of protecting the power system is not influenced. Therefore, when the operation data exceeds the limit value, the trip processing can be accurately and sensitively performed by the method for determining the fault of the power system based on the alternating current, and the power supply stability of the power system is guaranteed.
In an embodiment, as shown in fig. 5, the method for determining a fault of an electric power system based on an alternating current amount is implemented by the following steps: the collection time is t, the frequency of the current power system, namely the frequency of the first collected cycle is Fo, the frequency of the last collected cycle is Fp, the frequency change rate df/dt can be obtained by utilizing the conditions, and the frequency change rate df/dt is obtained according to the last cycleThe frequency Fp and the frequency change rate df/dt of the wave are used to obtain the period T of the next cycle1. Assuming that the third predetermined number is 32, according to T1And a third predetermined number 32 to obtain the next sampling time interval T1And/32, acquiring alternating current quantities A0, A1, A2 … … and A31 of 32 sampling points according to the time interval, calculating real parts and imaginary parts of (full-wave Fourier's) alternating current quantities A0-A2 and A3-A5 by using a full-wave Fourier algorithm on the assumption that the first preset number is 3, and then respectively calculating average effective values X of the sampling points A0-A2 and A3-A5 by using the calculation average effective value formula0(first effective value of AC quantity corresponding to first time in the above embodiment) and X1(corresponding to the first effective value of the alternating current amount at the second time in the above embodiment). Firstly, the effective value X is judged1And X0When X is1Less than or equal to 3X0When X is detected, the collection is performed again1Greater than 3X0And then preliminarily judging the signal mutation point existing in the collection amount.
Then utilizing full-wave Fourier algorithm to calculate real part and imaginary part of full-wave Fourier of corresponding sampling points from A6-A8 (alternating current of sampling points), then using said formula to calculate average effective value X2(corresponding to the first effective value of the AC quantity at the third time in the above embodiment), and then the first effective value X of the AC quantity at the third time is determined2And a second preset multiple of the effective value X of the first alternating current quantity at a second time1In relation to each other when X2Less than or equal to 0.7X1When X is detected, the collection is performed again2Greater than 0.7X1And if so, confirming that the alternating current quantity has a signal mutation point.
Then, the real part and the imaginary part of the alternating current quantity are calculated by the alternating current quantity of sampling points A3-A18 by utilizing a half-wave Fourier algorithm, and then the average effective value X of the alternating current quantity is calculated3(corresponding to the second effective value of the AC value in the above embodiment), compare X3Relation with the preset effective value Zn (corresponding to the preset effective value of the above-mentioned embodiment), when X3When the Zn content is less than or equal to 1.2Zn, collecting again, and when X is less than or equal to 1.2Zn3When the sampling channel is larger than 1.2Zn (1.2 times is a typical value, the times can be modified according to different use places), the out-of-limit effective value of the sampling channel alternating current can be judged。
Specifically, in order to judge more accurately, whether at least three alternating current sampling channels of current, voltage and power are out of limit or not can be monitored, when the alternating current sampling channels of any two channels are judged to have effective values larger than a preset effective value of a third preset multiple, the fact that a fault exists in the power system is determined, when the fact that the fault exists in the power system is determined, then a tripping instruction is sent out, fault information is written into an FRAM capable of being stored in a power failure mode, after 0.1 second of waiting, whether a switch of a protection object is tripped off or not is detected, if the switch is tripped off, the fault information is uploaded to the power monitoring system through a communication interface, and if not, the tripping instruction is sent out.
An embodiment of the present invention further provides an apparatus for determining a fault of an electric power system based on an ac flow, as shown in fig. 6, the apparatus includes:
the data processing module is used for determining the acquisition interval of the alternating current quantity sampling points according to the period of the alternating current quantity periodic wave; for details, refer to the related description of step S101 in the above method embodiment.
The data acquisition module is used for acquiring alternating current quantity frequency, acquiring alternating current quantity of a first preset number of sampling points based on the acquisition interval, and calculating to obtain a plurality of first alternating current quantity effective values according to a full-wave Fourier algorithm; for details, refer to the related description of step S102 in the above method embodiment.
The data judgment module is used for determining whether the alternating current quantity has signal mutation points or not based on the relation among the plurality of first alternating current quantity effective values; for details, refer to the related description of step S103 in the above method embodiment.
The information communication module is used for continuously acquiring the alternating current quantity of a second preset number of sampling points based on the acquisition interval when the signal mutation points exist, and calculating to obtain a second alternating current quantity effective value according to a half-wave Fourier algorithm; for details, refer to the related description of step S104 in the above method embodiment.
The judging and monitoring module is used for determining whether the power system has faults or not based on the relation between the second alternating current quantity effective value and a preset effective value; for details, refer to the related description of step S105 in the above method embodiment.
According to the device for determining the fault of the power system based on the alternating current, provided by the embodiment of the invention, through collecting multi-channel alternating current data, each channel calculates the effective value of the alternating current for multiple times, firstly, the relation between the effective values is judged, and then, the relation between the finally calculated effective value and the preset effective value is judged to determine whether the power system has the fault. The method considers the alternating current quantities of different sampling channels, and simultaneously judges the relationship between the effective values and the preset effective values for a plurality of times, so that the method provides a more accurate fault judgment device when the operation data exceeds the limit value objectively through the signal catastrophe point and the two judgments of the effective values. . Therefore, the power system fault determination device based on the alternating current amount can better maintain the stability of the power system.
An embodiment of the present invention further provides a storage medium, as shown in fig. 7, on which a computer program 601 is stored, where the instructions, when executed by a processor, implement the steps of the power system fault determination method based on the ac traffic in the foregoing embodiment. The storage medium is also stored with audio and video stream data, characteristic frame data, interactive request signaling, encrypted data, preset data size and the like. The storage medium may be a magnetic Disk, an optical Disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a Flash Memory (Flash Memory), a Hard Disk (Hard Disk Drive, abbreviated as HDD) or a Solid State Drive (SSD), etc.; the storage medium may also comprise a combination of memories of the kind described above.
It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by a computer program, which can be stored in a computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. The storage medium may be a magnetic Disk, an optical Disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a Flash Memory (Flash Memory), a Hard Disk (Hard Disk Drive, abbreviated as HDD) or a Solid State Drive (SSD), etc.; the storage medium may also comprise a combination of memories of the kind described above.
An embodiment of the present invention further provides an electronic device, as shown in fig. 8, the electronic device may include a processor 51 and a memory 52, where the processor 51 and the memory 52 may be connected by a bus or in another manner, and fig. 8 takes the connection by the bus as an example.
The processor 51 may be a Central Processing Unit (CPU). The Processor 51 may also be other general purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs) or other Programmable logic devices, discrete Gate or transistor logic devices, discrete hardware components, or combinations thereof.
The memory 52, which is a non-transitory computer readable storage medium, may be used to store non-transitory software programs, non-transitory computer executable programs, and modules, such as the corresponding program instructions/modules in the embodiments of the present invention. The processor 51 executes various functional applications and data processing of the processor by running non-transitory software programs, instructions and modules stored in the memory 52, that is, implements the method for determining the fault of the power system based on the alternating current amount in the above method embodiment.
The memory 52 may include a storage program area and a storage data area, wherein the storage program area may store an operating device, an application program required for at least one function; the storage data area may store data created by the processor 51, and the like. Further, the memory 52 may include high speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, flash memory device, or other non-transitory solid state storage device. In some embodiments, the memory 52 may optionally include memory located remotely from the processor 51, and these remote memories may be connected to the processor 51 via a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.
The one or more modules are stored in the memory 52 and, when executed by the processor 51, perform a method of cross-flow based power system fault determination as in the embodiment shown in fig. 1.
The details of the electronic device may be understood with reference to the corresponding related description and effects in the embodiment shown in fig. 1, and are not described herein again.
Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations fall within the scope defined by the appended claims.
Claims (10)
1. A method for determining a fault of a power system based on an alternating current amount is characterized by comprising the following steps:
determining the acquisition interval of the alternating current quantity sampling points according to the period of the alternating current quantity periodic wave;
acquiring alternating current of a first preset number of sampling points based on the acquisition interval, and calculating according to a full-wave Fourier algorithm to obtain a plurality of first alternating current effective values;
determining whether the alternating current quantity has a signal mutation point based on the relation among the plurality of first alternating current quantity effective values;
when the signal mutation point exists, continuously acquiring the alternating current quantity of a second preset number of sampling points based on the acquisition interval, and calculating according to a half-wave Fourier algorithm to obtain a second alternating current quantity effective value;
and determining whether the power system has faults or not based on the relationship between the second alternating current quantity effective value and the preset effective value.
2. The method for determining the fault of the power system based on the alternating current quantity according to claim 1, wherein the step of determining the collection interval of the sampling point of the alternating current quantity according to the periodic collection of the periodic wave of the alternating current quantity comprises the following steps:
collecting the frequency of each cycle of the alternating current;
determining the period of the next cycle according to the frequency change rate obtained by calculating the frequency of each cycle and the frequency of the current power system;
and determining the acquisition interval of the alternating flow sampling points according to the period and the third preset number.
3. The method for determining the fault of the power system based on the alternating current according to claim 1, wherein the step of obtaining the alternating current of a first preset number of sampling points based on the collection interval and calculating a plurality of first alternating current effective values according to a full-wave fourier algorithm comprises:
acquiring the alternating current of a first preset number of sampling points based on the acquisition interval, and calculating to obtain a first alternating current effective value at a first time according to a full-wave Fourier algorithm;
and continuously acquiring the alternating current quantity of the first preset number of sampling points based on the acquisition interval, and calculating to obtain a first alternating current quantity effective value at a second time according to a full-wave Fourier algorithm.
4. The method of claim 3, wherein determining whether the signal discontinuity exists in the ac power system based on the relationship between the plurality of first ac power effective values comprises:
judging the relation between the first alternating current quantity effective value at the second time and the first alternating current quantity effective value at the first time of a first preset multiple;
and when the first alternating current quantity effective value at the second time is larger than the first alternating current quantity effective value at the first time of a first preset multiple, determining that a signal mutation point exists in the alternating current quantity.
5. The method for determining the fault of the power system based on the alternating current amount according to claim 4, before continuing to obtain the alternating current amount of the second preset number of sampling points based on the collection interval, further comprising:
when signal catastrophe points exist, continuously acquiring the alternating current quantity of a first preset number of sampling points based on the acquisition interval, and calculating to obtain a first alternating current quantity effective value at a third time according to a full-wave Fourier algorithm;
judging the relation between the first alternating current quantity effective value at the third time and the first alternating current quantity effective value at the second time of a second preset multiple;
and when the first alternating current quantity effective value at the third time and the first alternating current quantity effective value at the second time of a second preset multiple are obtained, determining that a signal mutation point exists in the alternating current quantity.
6. The method of claim 1, wherein the ac traffic comprises a multi-channel voltage ac traffic, a multi-channel current ac traffic, and a multi-channel power ac traffic;
determining whether the power system has a fault based on the relationship between the second alternating current quantity effective value and the preset effective value, wherein the determining comprises the following steps:
and when any two channel alternating current quantity effective values in the voltage alternating current quantity effective value, the current alternating current quantity effective value and the power alternating current quantity effective value are larger than a preset effective value of a third preset multiple, determining that the power system has a fault.
7. The ac-flow-based power system fault determination method as claimed in claim 1, further comprising:
when the power system is determined to have a fault, a tripping instruction is sent out;
judging whether a switch of an object to be protected is tripped after preset time;
if the tripping operation is not carried out, a tripping instruction is continuously sent out;
and if the power system is tripped, uploading the fault existing in the power system to the power monitoring system.
8. An electrical power system fault determination device based on an amount of alternating current, comprising:
the data processing module is used for determining the acquisition interval of the alternating current quantity sampling points according to the period of the alternating current quantity periodic wave;
the data acquisition module is used for acquiring alternating current quantity frequency and obtaining alternating current quantity of a first preset number of sampling points based on the acquisition interval, and calculating to obtain a plurality of first alternating current quantity effective values according to a full-wave Fourier algorithm;
the data judgment module is used for determining whether the alternating current quantity has signal mutation points or not based on the relation among the first alternating current quantity effective values;
the information communication module is used for continuously acquiring the alternating current quantity of a second preset number of sampling points based on the acquisition interval when signal catastrophe points exist, and calculating to obtain a second alternating current quantity effective value according to a half-wave Fourier algorithm;
and the judging and monitoring module is used for determining whether the power system has faults or not based on the relationship between the second alternating current effective value and the preset effective value.
9. A computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions for causing the computer to execute the safety state assessment method of the power internet of things terminal according to any one of claims 1 to 7.
10. An electronic device, comprising: the electric power internet of things terminal safety state evaluation method comprises a memory and a processor, wherein the memory and the processor are mutually connected in a communication mode, the memory stores computer instructions, and the processor executes the computer instructions so as to execute the electric power internet of things terminal safety state evaluation method according to any one of claims 1-7.
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| WO2024045100A1 (en) * | 2022-08-31 | 2024-03-07 | 清华大学 | Relaying protection method, apparatus and device for three-phase alternating-current system |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2024045100A1 (en) * | 2022-08-31 | 2024-03-07 | 清华大学 | Relaying protection method, apparatus and device for three-phase alternating-current system |
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