Fault channel selection method and system for aligning multiple homologous asynchronous waveforms

Abstract

The present invention discloses a fault channel selection method and system for aligning multiple homologous asynchronous waveforms, the method comprising: collecting homologous waveforms wave1 and wave2 after a power grid fault occurs, selecting analog channels with the same physical meaning therefrom, calculating the amplitude of the analog channels, obtaining the analog amplitude, calculating the amplitude mutation amount at each sampling moment, forming amplitude mutation amount data, thereby screening the fault moments of waveforms wave1 and wave2; comparing the analog amplitude difference of waveform segments commonly included in waveforms wave1 and wave2 before and after their respective fault moments, and when the difference criterion is met, selecting the current analog channel as the fault channel for waveform alignment, otherwise reselecting the analog channel. The present invention correctly selects the fault channel for aligning multiple homologous asynchronous waveforms in complex situations where there may be a voltage transformer or a current transformer disconnection and there are disturbances and faults coexisting in the analog channel.

Description

Technical Field

[0001] The present invention belongs to the technical field of power system operation and maintenance, and relates to a fault channel selection method and system for aligning multiple homologous asynchronous waveforms. Background Art

[0002] The correctness of the voltage and current collected by the relay protection device and the fault recorder in the substation is an important concern of the relay protection. The automatic verification of voltage and current has become an important task of intelligent operation and maintenance of substations. The fault recordings generated by the relay protection device and the fault recorder when the power system is disturbed or fails can be compared to verify whether there are any abnormalities in the analog quantity sampling. Different fault recordings are asynchronous sampling recordings, and the waveforms need to be aligned before comparing the analog quantities.

[0003] The criterion input used for waveform alignment is the analog sampling channel data in the waveform. Since the analog sampling of the power system is periodic, if the analog channel does not change in all cycles of the entire waveform, then the analog channel does not meet the conditions for alignment. Therefore, the existing technology uses the method of calculating the sudden change of the sampling value to find the fault point, and then continues the alignment step based on the fault point.

[0004] Since the waveforms of the relay protection device and the fault recorder are different in startup and the recording length of the fault recorder is much longer than that of the relay protection device, it is actually difficult to find the fault point for waveform alignment, especially when a fault occurs when there is a certain disturbance in the analog quantity of the power system itself. In particular, the recording may also be accompanied by the disconnection of the voltage transformer or the current transformer and other analog quantity sampling situations, which may lead to errors in the selection of the fault point and the selection of the analog quantity channel, resulting in the failure of waveform alignment. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the present invention provides a method and system for selecting a fault channel for aligning multiple homologous asynchronous waveforms, which can correctly select the fault channel for aligning multiple homologous asynchronous waveforms in complex situations where a voltage transformer or a current transformer may be broken and disturbances and faults coexist in analog channels.

[0006] The present invention adopts the following technical solution.

[0007] A first aspect of the present invention provides a method for selecting a fault channel for aligning a plurality of homologous asynchronous waveforms, comprising:

[0008] Step 1: Collect a set of waveforms wave1 and wave2 of the same source after a power grid fault occurs;

[0009] Step 2: Select analog channels with the same physical meaning from waveform wave1 and waveform wave2, and calculate the amplitudes of the analog channels of waveform wave1 and waveform wave2 respectively to obtain the analog amplitudes of waveform wave1 and waveform wave2;

[0010] Step 3: Calculate the amplitude mutation amount of the analog amplitude of waveform wave1 and waveform wave2 at each sampling moment, and form the amplitude mutation amount data of waveform wave1 and waveform wave2;

[0011] Step 4: Filter the fault moments of waveforms wave1 and wave2 according to the amplitude mutation data of waveforms wave1 and wave2;

[0012] Step 5: Compare the difference in analog amplitude of the waveform segments commonly contained in waveform wave1 and waveform wave2 before and after their respective fault moments. When the difference criterion is met, select the current analog channel as the fault channel for homologous asynchronous waveform alignment, otherwise return to step 2 to reselect the analog channel.

[0013] Preferably, in step 1, the waveform wave1 is collected by a relay protection device, and the waveform wave2 is collected by an intelligent recorder.

[0014] Preferably, in step 2, the analog channels with the same physical meaning refer to voltage channels with the same phase or current channels with the same phase, and if there are voltage channels in the waveform, the voltage channels with the same phase are preferentially selected.

[0015] Preferably, in step 3, the amplitude mutation calculation formula is:

[0016] (1)

[0017] Where: for The amplitude mutation at the moment;

[0018] for The analog amplitude at the moment;

[0019] for The analog amplitude of the previous cycle;

[0020] is the number of sampling points in one cycle.

[0021] Preferably, in step 4, the time t1 satisfying the following formula is selected as the waveform The fault moment, t2 is selected as the waveform The moment of failure:

[0022] (2)

[0023] Where: For waveform exist The amplitude mutation at the moment;

[0024] For waveform exist The amplitude mutation at the moment;

[0025] Set the value of the difference in amplitude mutation amount;

[0026] Set the amplitude mutation threshold.

[0027] Preferably, is 0.1, is 0.05.

[0028] Preferably, in step 5, the difference criterion is:

[0029] (3)

[0030] Where: For waveform exist The analog amplitude at the moment;

[0031] For waveform exist The analog amplitude at the moment;

[0032] Set the value for the analog amplitude difference;

[0033] Set the analog value amplitude comparison threshold;

[0034] is the waveform sampling period;

[0035] t1 and t2 represent the fault moments of waveform wave1 and waveform wave2 respectively.

[0036] Preferably, for the voltage channel, is 1, is 1;

[0037] For the current channel, is 0.1, is 0.1.

[0038] A second aspect of the present invention provides a fault channel selection system for aligning multiple homologous asynchronous waveforms, comprising:

[0039] A waveform acquisition module, used for acquiring a set of waveforms wave1 and waveform wave2 of the same source after a power grid fault occurs;

[0040] The amplitude calculation module is used to select analog channels with the same physical meaning from waveform wave1 and waveform wave2, and calculate the amplitudes of the analog channels of waveform wave1 and waveform wave2 respectively, so as to obtain the analog amplitudes of waveform wave1 and waveform wave2;

[0041] The mutation amount calculation module is used to calculate the amplitude mutation amount of the analog amplitude of the waveform wave1 and the waveform wave2 at each sampling moment, so as to form the amplitude mutation amount data of the waveform wave1 and the waveform wave2;

[0042] A fault time screening module is used to screen the fault time of waveform wave1 and waveform wave2 according to the amplitude mutation amount data of waveform wave1 and waveform wave2;

[0043] The fault channel selection module is used to compare the difference in analog amplitude of the waveform segments commonly contained in waveform wave1 and waveform wave2 before and after their respective fault moments. When the difference criterion is met, the current analog channel is selected as the fault channel for homologous asynchronous waveform alignment. Otherwise, it returns to the amplitude calculation module to reselect the analog channel.

[0044] A terminal comprises a processor and a storage medium; the storage medium is used to store instructions; the processor is used to operate according to the instructions to execute the steps of the method.

[0045] A computer-readable storage medium stores a computer program, which implements the steps of the method when executed by a processor.

[0046] Compared with the prior art, the beneficial effects of the present invention include at least:

[0047] The present invention calculates and compares a plurality of analog quantity mutations that may exist in a waveform, and can adapt to the situation where disturbance exists in the waveform and fault characteristics coexist, and correctly select the fault moment of the analog quantity.

[0048] The present invention can adapt to the situation where a voltage transformer or a current transformer may be disconnected in the waveform by calculating and comparing the analog quantities before and after the selected fault moment, and prevent the waveform from being misaligned due to selecting an erroneous analog quantity channel during alignment.

[0049] The present invention can effectively prevent the problem of incorrect selection of fault time during waveform alignment and failure to align waveforms due to the presence of multiple fault characteristic moments in a certain waveform by screening the fault moment and judging the difference of analog quantities before and after the fault moment. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 The present invention is a flow chart of a method for selecting a fault channel for aligning multiple homologous asynchronous waveforms. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only embodiments of a part of the present invention, rather than all embodiments. Based on the spirit of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0052] Embodiment 1 of the present invention provides a method for selecting a fault channel for aligning multiple same-source asynchronous waveforms, such as Figure 1 As shown, including:

[0053] Step 1: Use a relay protection device and an intelligent recorder to collect a set of waveforms wave1 and wave2 of the same source after a power grid fault occurs;

[0054] Collect the waveform of the relay protection device of the same source after a power grid fault occurs And intelligent recorder waveform ;

[0055] Step 2: Select analog channels with the same physical meaning from waveform wave1 and waveform wave2, and calculate the amplitudes of the analog channels of waveform wave1 and waveform wave2 respectively to obtain the analog amplitudes of waveform wave1 and waveform wave2;

[0056] This step extracts analog channels with the same physical meaning in waveform wave1 and waveform wave2, and uses a full-cycle Fourier algorithm to respectively calculate the amplitudes of the analog channels.

[0057] Further preferably, the analog channels with the same physical meaning refer to the same-phase voltage channels or the same-phase current channels. If there are voltage channels in the waveform, the voltage channel is preferentially selected for judgment. If there is no voltage channel, the current channel is selected for judgment.

[0058] For example, if you obtain the A phase voltage channel and , the full-cycle Fourier algorithm is used to calculate the analog amplitude of the voltage channel respectively.

[0059] Step 3: Calculate the amplitude mutation amount of the analog amplitude of waveform wave1 and waveform wave2 at each sampling moment, and form the amplitude mutation amount data of waveform wave1 and waveform wave2;

[0060] This step calculates the amplitude mutation of the analog channel at each sampling moment. Specifically:

[0061] The mutation amount at each sampling moment is calculated for the two sets of analog amplitudes obtained in step 2 to form two sets of mutation amount data. and ;

[0062] The calculation formula of amplitude mutation is:

[0063] (1)

[0064] Where: for The amplitude mutation at the moment;

[0065] for The analog amplitude at the moment;

[0066] for The analog amplitude of the previous cycle;

[0067] is the number of sampling points in one cycle.

[0068] Step 4: Filter the fault moments of waveforms wave1 and wave2 according to the amplitude mutation data of waveforms wave1 and wave2;

[0069] This step compares the amplitude mutation of the analog value and selects the moment with the same mutation characteristics as the fault moment. Specifically:

[0070] right and Calculate according to formula (2);

[0071] (2)

[0072] Where: For waveform exist The amplitude mutation at the moment;

[0073] For waveform exist The amplitude mutation at the moment;

[0074] Set the value of the difference in amplitude mutation amount;

[0075] Set the amplitude mutation threshold.

[0076] As a preferred embodiment of the present invention, Set to 0.1, Set to 0.05;

[0077] The time t1 that satisfies formula (2) is taken as the waveform The fault moment, t2 moment is the waveform The moment of failure.

[0078] Step 5: Compare the difference in analog amplitude of the waveform segments commonly contained in waveform wave1 and waveform wave2 before and after their respective fault moments. When the difference criterion is met, select the current analog channel as the fault channel for homologous asynchronous waveform alignment, otherwise return to step 2 to reselect the analog channel.

[0079] This step compares the analog amplitude difference of the waveform segments commonly included in waveform wave1 and waveform wave2 before and after their respective fault moments. If the analog amplitude difference comparison is satisfied, the analog channel is selected as the fault channel for homologous asynchronous waveform alignment, otherwise, the next group of analog channels is judged. and In the waveform segments that are commonly included before and after the respective fault moments, the difference in analog amplitude of the waveform segment is compared point by point using formula (3);

[0080] (3)

[0081] Where: For waveform exist The analog amplitude at the moment;

[0082] For waveform exist The analog amplitude at the moment;

[0083] Set the value for the analog amplitude difference;

[0084] Set the analog value amplitude comparison threshold;

[0085] is the waveform sampling period.

[0086] As a preferred solution of the present invention, when the channel is a voltage channel, the formula (3) Set to 1, Set to 1;

[0087] When the channel is a current channel, the Set to 0.1, Set to 0.1.

[0088] if and When the analog quantity comparisons all satisfy formula (3), the A-phase voltage channel can be selected as the fault channel for waveform alignment; if there is a situation that does not satisfy formula (3), continue to judge the next group of analog quantity channels in steps 2 to 4.

[0089] Embodiment 2 of the present invention provides a fault channel selection system for aligning multiple homologous asynchronous waveforms, including:

[0090] A waveform acquisition module, used for acquiring a set of waveforms wave1 and waveform wave2 of the same source after a power grid fault occurs;

[0091] The amplitude calculation module is used to select analog channels with the same physical meaning from waveform wave1 and waveform wave2, and calculate the amplitudes of the analog channels of waveform wave1 and waveform wave2 respectively, so as to obtain the analog amplitudes of waveform wave1 and waveform wave2;

[0092] The mutation amount calculation module is used to calculate the amplitude mutation amount of the analog amplitude of the waveform wave1 and the waveform wave2 at each sampling moment, so as to form the amplitude mutation amount data of the waveform wave1 and the waveform wave2;

[0093] A fault time screening module is used to screen the fault time of waveform wave1 and waveform wave2 according to the amplitude mutation amount data of waveform wave1 and waveform wave2;

[0094] The fault channel selection module is used to compare the difference in analog amplitude of the waveform segments commonly contained in waveform wave1 and waveform wave2 before and after their respective fault moments. When the difference criterion is met, the current analog channel is selected as the fault channel for homologous asynchronous waveform alignment. Otherwise, it returns to the amplitude calculation module to reselect the analog channel.

[0095] Embodiment 3 of the present invention provides a terminal, including a processor and a storage medium; the storage medium is used to store instructions; the processor is used to operate according to the instructions to execute the steps of the method.

[0096] Embodiment 4 of the present invention provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of the method when executed by a processor.

[0097] Compared with the prior art, the beneficial effects of the present invention include at least:

[0098] The present invention calculates and compares a plurality of analog quantity mutations that may exist in a waveform, and can adapt to the situation where disturbance exists in the waveform and fault characteristics coexist, and correctly select the fault moment of the analog quantity.

[0099] The present invention can adapt to the situation where a voltage transformer or a current transformer may be disconnected in the waveform by calculating and comparing the analog quantities before and after the selected fault moment, and prevent the waveform from being misaligned due to selecting an erroneous analog quantity channel during alignment.

[0100] The fault moment screening and analog quantity difference judgment before and after the fault moment of the present invention can effectively prevent the existence of multiple fault characteristic moments in a certain waveform, which leads to the problem of wrong fault moment selection during waveform alignment and inability to align the waveforms.

[0101] The present disclosure may be a system, a method and / or a computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present disclosure.

[0102] A computer-readable storage medium may be a tangible device that can hold and store instructions used by an instruction execution device. A computer-readable storage medium may be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the above. More specific examples (a non-exhaustive list) of computer-readable storage media include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, such as a punch card or a raised structure in a groove on which instructions are stored, and any suitable combination of the above. The computer-readable storage medium used herein is not to be interpreted as a transient signal itself, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., a light pulse through a fiber optic cable), or an electrical signal transmitted through a wire.

[0103] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to each computing / processing device, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical fiber transmissions, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in the computer-readable storage medium in each computing / processing device.

[0104] The computer program instructions for performing the operations of the present disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages, such as Smalltalk, C++, etc., and conventional procedural programming languages, such as "C" language or similar programming languages. The computer-readable program instructions may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer, partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., using an Internet service provider to connect through the Internet). In some embodiments, by using the state information of the computer-readable program instructions to personalize an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), the electronic circuit may execute the computer-readable program instructions, thereby implementing various aspects of the present disclosure.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for selecting a fault channel for aligning multiple homologous asynchronous waveforms, characterized in that: The method comprises: Step 1: Collect a set of waveforms wave1 and wave2 of the same source after a power grid fault occurs; Step 2: Select analog channels with the same physical meaning from waveform wave1 and waveform wave2, and calculate the amplitudes of the analog channels of waveform wave1 and waveform wave2 respectively to obtain the analog amplitudes of waveform wave1 and waveform wave2, wherein the analog channels with the same physical meaning refer to the same-phase voltage channels or the same-phase current channels; Step 3: Calculate the amplitude mutation amount of the analog amplitude of waveform wave1 and waveform wave2 at each sampling moment, and form the amplitude mutation amount data of waveform wave1 and waveform wave2; Step 4: Filter the fault moments of waveforms wave1 and wave2 according to the amplitude mutation data of waveforms wave1 and wave2; Step 5: Compare the difference in analog amplitude of waveform segments commonly included in waveform wave1 and waveform wave2 before and after their respective fault moments. If the difference criterion is met, select the current analog channel as the fault channel for homologous asynchronous waveform alignment. Otherwise, return to step 2 to reselect the analog channel. The difference criterion is: （3） Where: For waveform exist The analog amplitude at the moment; For waveform exist The analog amplitude at the moment; Set the value for the analog amplitude difference; Set the analog value amplitude comparison threshold; is the waveform sampling period; t1 and t2 represent the fault moments of waveform wave1 and waveform wave2 respectively.

2. A method for selecting a fault channel for aligning multiple homologous asynchronous waveforms according to claim 1, characterized in that: In step 1, the waveform Wave1 is collected by using a relay protection device, and the waveform Wave2 is collected by using an intelligent recorder.

3. A method for selecting a fault channel for aligning multiple homologous asynchronous waveforms according to claim 1, characterized in that: In step 2, if there are voltage channels in the waveform, the voltage channel with the same phase is preferentially selected.

4. A method for selecting a fault channel for aligning multiple homologous asynchronous waveforms according to claim 1, characterized in that: In step 3, the calculation formula for the amplitude mutation is: （1） Where: for The amplitude mutation at the moment; for The analog amplitude at the moment; for The analog amplitude of the previous cycle; is the number of sampling points in one cycle.

5. The method for selecting a fault channel for aligning multiple homologous asynchronous waveforms according to claim 1, characterized in that: In step 4, the time t1 that satisfies the following equation is selected as the waveform The fault time, t2 is selected as the waveform The moment of failure: （2） Where: For waveform exist The amplitude mutation at the moment; For waveform exist The amplitude mutation at the moment; Set the value of the difference in amplitude mutation amount; Set the value of the amplitude mutation threshold.

6. A method for selecting a fault channel for aligning multiple homologous asynchronous waveforms according to claim 5, characterized in that: is 0.1, is 0.

05.

7. A method for selecting a fault channel for aligning multiple same-source asynchronous waveforms according to claim 1, characterized in that: For the voltage channel, is 1, is 1; For the current channel, is 0.1, is 0.

1.

8. A fault channel selection system for aligning multiple homologous asynchronous waveforms, using the method according to any one of claims 1 to 7, characterized in that: The system comprises: A waveform acquisition module, used for acquiring a set of waveforms wave1 and waveform wave2 of the same source after a power grid fault occurs; The amplitude calculation module is used to select analog channels with the same physical meaning from waveform wave1 and waveform wave2, and calculate the amplitudes of the analog channels of waveform wave1 and waveform wave2 respectively, so as to obtain the analog amplitudes of waveform wave1 and waveform wave2; The mutation amount calculation module is used to calculate the amplitude mutation amount of the analog amplitude of the waveform wave1 and the waveform wave2 at each sampling moment, so as to form the amplitude mutation amount data of the waveform wave1 and the waveform wave2; A fault time screening module is used to screen the fault time of waveform wave1 and waveform wave2 according to the amplitude mutation amount data of waveform wave1 and waveform wave2; The fault channel selection module is used to compare the difference in analog amplitude of the waveform segments commonly contained in waveform wave1 and waveform wave2 before and after their respective fault moments. When the difference criterion is met, the current analog channel is selected as the fault channel for homologous asynchronous waveform alignment. Otherwise, it returns to the amplitude calculation module to reselect the analog channel.

9. A terminal comprising a processor and a storage medium; characterized in that: The storage medium is used to store instructions; The processor is configured to operate according to the instructions to execute the steps of the method according to any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

Images