CN117330884A - Early fault positioning method and system for direct-current line of intelligent power distribution room - Google Patents

Early fault positioning method and system for direct-current line of intelligent power distribution room Download PDF

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Publication number
CN117330884A
CN117330884A CN202311024557.4A CN202311024557A CN117330884A CN 117330884 A CN117330884 A CN 117330884A CN 202311024557 A CN202311024557 A CN 202311024557A CN 117330884 A CN117330884 A CN 117330884A
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China
Prior art keywords
response time
early
distribution room
power distribution
fault
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CN202311024557.4A
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Chinese (zh)
Inventor
辛明勇
徐长宝
林呈辉
高吉普
王宇
杨婧
冯起辉
何雨旻
祝健杨
徐玉韬
范强
吕黔苏
古庭赟
汪明媚
李博文
张后谊
毛钧毅
代奇迹
张宣
王林波
王元峰
马文磊
曾惜
张轶灵
王恩伟
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Guizhou Power Grid Co Ltd
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Guizhou Power Grid Co Ltd
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Priority to CN202311024557.4A priority Critical patent/CN117330884A/en
Publication of CN117330884A publication Critical patent/CN117330884A/en
Pending legal-status Critical Current

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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
    • G01R31/08—Locating faults in cables, transmission lines, or networks
    • G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
    • G01R31/085—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution lines, e.g. overhead
    • 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
    • G01R31/08—Locating faults in cables, transmission lines, or networks
    • G01R31/088—Aspects of digital computing
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
    • H02H7/268—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured for dc systems
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
    • Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
    • Y04S10/52—Outage or fault management, e.g. fault detection or location

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Mathematical Physics (AREA)
  • Theoretical Computer Science (AREA)
  • Remote Monitoring And Control Of Power-Distribution Networks (AREA)

Abstract

The invention relates to the technical field of power systems, in particular to an early fault positioning method and system for a direct current line of an intelligent power distribution room, comprising the steps of acquiring data of a monitoring system in the intelligent power distribution room and terminal power electronic equipment in a range of jurisdiction, and injecting an initiating instruction for current and disturbance injection of each branch in the intelligent power distribution room; solving the system response time, obtaining the system response time by using the filtered measurement result, and comparing the system response time with the normal system response time of the system to obtain an early fault region; after the early fault area is identified, a trip instruction is sent to the circuit breaker through logic operation. The invention can detect the early faults in the power system on the premise of no power failure, and locate and isolate the risk areas before the faults develop into short-circuit faults, thereby ensuring the safe and stable operation of the whole system.

Description

Early fault positioning method and system for direct-current line of intelligent power distribution room
Technical Field
The invention relates to the technical field of power systems, in particular to an early fault positioning method and system for a direct current line of an intelligent power distribution room.
Background
The intelligent power distribution room is used as a bridge for connecting source-load-storage, so that electric energy is collected and distributed, and meanwhile, abundant measurement and control and operation units provide conditions for intelligent operation and maintenance. The early faults of the cable are hidden and are not easy to detect and identify, and once the short circuit faults occur, the circuit is tripped, so that load loss is caused, and impact is brought to other units in the system. In order to detect early faults of cables, some detection methods have been proposed, and one type of detection method is to complete detection and discrimination according to non-electrical quantity information, such as sensing signals of sound waves, images, light and the like. However, the method has poor detection sensitivity, and simultaneously, a large number of non-electrical quantity sensors are arranged at high cost, so that the method is not beneficial to large-area popularization and application. Another type of method is to use an injection voltage wave signal and detect a reflected wave, to generate wave reflection at an early failure by setting the amplitude and period of the injection voltage wave, and then to determine whether an early failure occurs by detecting the amplitude, wave head time, and frequency domain information of the reflected wave. The method has wide application range at present, but the detection can be completed only by power failure, and the additionally injected high-frequency voltage signal is also an impact to the cable, so that the service life of the cable is reduced to a certain extent. Therefore, how to fully utilize the measurement and control units and the operation units arranged in the construction process of the intelligent power distribution room, and combine the increasingly-increased power electronic power units in the novel power system by adopting an advanced communication means, and detect the early faults of the cable by adopting a disturbance injection mode on the premise of no power failure is the key of the technology.
Disclosure of Invention
The present invention has been made in view of the above-described problems.
Therefore, the technical problems solved by the invention are as follows: in consideration of measurement and control units and operation units arranged in the construction process of the intelligent power distribution room and the combined power electronic type power unit, the method and the system for positioning the early faults of the direct current line of the intelligent power distribution room are provided, the early faults in the power system can be detected on the premise of no power failure, and the risk areas are positioned and isolated before the faults develop into short-circuit faults, so that the safe and stable operation of the whole system is ensured.
In order to solve the technical problems, the invention provides the following technical scheme: acquiring data of a monitoring system in an intelligent power distribution room and terminal power electronic equipment in a governed range, and injecting an initiating instruction for current and disturbance injection of each branch in the intelligent power distribution room; solving the system response time, obtaining the system response time by using the filtered measurement result, and comparing the system response time with the normal system response time of the system to obtain an early fault region; after the early fault area is identified, a trip instruction is sent to the circuit breaker through logic operation.
As a preferable scheme of the intelligent power distribution room direct current line early fault positioning method, the invention comprises the following steps: the terminal power electronic equipment data comprise current data, voltage data and fluctuation amplitude data of current and voltage in a terminal monitoring system; the disturbance injection initiating instruction comprises an instruction for introducing a specific external disturbance signal into the power system, the system response time after the disturbance injection is recorded, and the response and stability of the power system are tested according to the recorded response time.
As a preferable scheme of the intelligent power distribution room direct current line early fault positioning method, the invention comprises the following steps: the disturbance injection initiating instruction further comprises disturbance injectionSelecting power electronic equipment adopting voltage type control and giving a voltage command u ref Superimposed disturbance injection value a in After entering the voltage control loop, obtaining a current instruction value I ref ：
I ref ＝G(s)[u ref +a in (u(t-t ins )-u(t-t end ))-u mea ]
Wherein G(s) is the transfer coefficient of the voltage outer loop, u (t-t) ins ) And u (t-t) end ) Respectively indicate the start t ins And end t end Step function of time, u mea Is the output voltage value.
As a preferable scheme of the intelligent power distribution room direct current line early fault positioning method, the invention comprises the following steps: : the response time of the solving system comprises the steps of monitoring current change in the power system by using a sensor after disturbance instructions are injected, collecting current data changed in the power system, and carrying out mean filtering denoising processing on the collected current data, wherein the mean filtering processing is as follows:
wherein y N is the denoised current signal sample, x N is the original current signal sample, and N is the window size;
noise is reduced by calculating the average value of data in a current signal window, interference values in the acquired current data are reduced, a system response starting point and a system response ending point after disturbance injection are found out in the current signal data after filtering and denoising, and the time difference between the response starting point and the response ending point is calculated:
ΔT＝T I -T i
wherein T is I For the system response end point time, T i The time difference deltat is the system response time, which is the system response start point time.
As a preferable scheme of the intelligent power distribution room direct current line early fault positioning method, the invention comprises the following steps: the fault area comprises a plurality of subareas, the whole power system and each subarea have response time ranges, step response time in current sampling of subarea nodes in a disturbance process is separated, the structure of a power system network can be changed when early faults occur in the power system, the response speed of the power system can be obviously slowed down when the structure of the power system network is changed, and when the response speed in the power system after disturbance is injected is obviously greater than the intrinsic response speed of the power system, the early faults of insulation occur in the power system area.
As a preferable scheme of the intelligent power distribution room direct current line early fault positioning method, the invention comprises the following steps: when detecting that the response time in the power system area changes, if the change range of the response change time exceeds a change time threshold value, judging that an early fault occurs in the power system, checking the response time of a partition range in the power system, issuing a tripping instruction to the partition with the increased response time, and isolating the early fault in the partition; if the response time in the power system area is detected to change, but the change range of the response time does not exceed the change time threshold, judging that no early fault occurs in the power system, and not issuing a tripping instruction.
As a preferable scheme of the intelligent power distribution room direct current line early fault positioning method, the invention comprises the following steps: the tripping instruction comprises that after judging the power system fault result according to the change of the response time of the power system, the power system outputs the fault result, the fault partition in the power system is found out, the circuit breakers on the two sides of the fault partition are tripped, and the fault area is isolated before the early fault evolves into a permanent fault.
The invention further aims to provide an intelligent power distribution room direct current line early fault positioning system which can realize detection and positioning of early faults in a power system area by constructing a fault positioning system, realize automatic processing of the early faults in the power system area and prevent the early faults from developing into permanent faults.
As a preferable scheme of the intelligent power distribution room direct current line early fault positioning system, the invention comprises the following steps: the system comprises a data communication module, a data processing module and a logic execution module; the data communication module is used for acquiring data of a monitoring system in the intelligent power distribution room and terminal power electronic equipment in the range of the intelligent power distribution room, and injecting an initiating instruction to each branch current and disturbance in the intelligent power distribution room; the data processing module is used for solving the system response time, obtaining the system response time by using the filtered measurement result, and comparing the system response time with the normal system response time of the system to obtain an early fault area; and the logic execution module is used for executing a tripping instruction on an early fault area when judging that the early fault of the area exists in the power system.
The invention also provides computer equipment, which comprises a memory and a processor, wherein the memory stores a computer program, and is characterized in that the processor realizes the steps of the intelligent power distribution room direct current line early fault positioning method when executing the computer program.
The invention also provides a computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when executed by a processor, implements the steps of the method for locating early faults of a direct current line of an intelligent power distribution room.
The invention has the beneficial effects that: the method provided by the invention has the advantages that power failure is not needed in the detection process, the detection can be completed only by adding a micro-weak disturbance instruction into the power electronic type power unit control unit, the influence in the detection process is low, and other loads and loads in a power grid are not influenced; the method provided by the invention is independent of the establishment of the accurate model of the equipment in the intelligent power distribution room in terms of data processing, and meanwhile, the consumed computing resources are small, the method can be completed by using the existing computing platform, the implementation cost is low, and the equipment is not required to be newly added.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art. Wherein:
fig. 1 is a flow chart of an early fault positioning method for a direct current line of an intelligent power distribution room.
Fig. 2 is a system structure diagram of an intelligent power distribution room direct current line early fault positioning system provided by the invention.
Fig. 3 is a schematic diagram of an electric power system architecture of an intelligent power distribution room dc line early fault positioning method provided by the invention.
Fig. 4 is a diagram of an example network structure of a method for positioning early faults of a direct current line of an intelligent power distribution room.
Fig. 5 is a diagram of a comparison detection result of an intelligent power distribution room direct current line early fault positioning method.
Detailed Description
So that the manner in which the above recited objects, features and advantages of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments, some of which are illustrated in the appended drawings. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways other than those described herein, and persons skilled in the art will readily appreciate that the present invention is not limited to the specific embodiments disclosed below.
Further, reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic can be included in at least one implementation of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.
While the embodiments of the present invention have been illustrated and described in detail in the drawings, the cross-sectional view of the device structure is not to scale in the general sense for ease of illustration, and the drawings are merely exemplary and should not be construed as limiting the scope of the invention. In addition, the three-dimensional dimensions of length, width and depth should be included in actual fabrication.
Also in the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper, lower, inner and outer", etc. are based on the orientation or positional relationship shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first, second, or third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
The terms "mounted, connected, and coupled" should be construed broadly in this disclosure unless otherwise specifically indicated and defined, such as: can be fixed connection, detachable connection or integral connection; it may also be a mechanical connection, an electrical connection, or a direct connection, or may be indirectly connected through an intermediate medium, or may be a communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
Example 1
Referring to fig. 1, for a first embodiment of the present invention, an intelligent power distribution room dc line early fault location method is provided.
S1: and acquiring data of a monitoring system in the intelligent power distribution room and terminal power electronic equipment in a range of the intelligent power distribution room, and injecting an initiating instruction for current and disturbance injection of each branch in the intelligent power distribution room.
Specifically, the terminal power electronic equipment data comprise current data, voltage data and fluctuation amplitude data of current and voltage in a terminal monitoring system;
the disturbance injection initiating instruction comprises an instruction for introducing a specific external disturbance signal into the power system, the system response time after the disturbance injection is recorded, and the response and stability of the power system are tested according to the recorded response time.
Further, the disturbance injection initiating instruction further comprises selecting a power electronic device controlled by a voltage type, and executing a voltage instruction u ref Superimposed disturbance injection value a in After entering the voltage control loop, obtaining a current instruction value I ref ：
I ref ＝g(s)[u ref +a in (u(t-t ins )-u(t-t end ))-u mea ]
Wherein G(s) is the transfer coefficient of the voltage outer loop, u (t-t) ins ) And u (t-t) end ) Respectively indicate the start t ins And end t end Step function of time, u mea Is the output voltage value.
S2: and solving the system response time, obtaining the system response time by using the filtered measurement result, and comparing the system response time with the normal system response time of the system to obtain an early fault region.
Specifically, the response time of the solving system includes that after a disturbance instruction is injected, a sensor is used for monitoring current change in the power system, current data of the change in the power system are collected, mean filtering denoising processing is carried out on the collected current data, and the mean filtering processing is as follows:
where y N is the denoised current signal sample, x N is the original current signal sample, and N is the window size.
Noise is reduced by calculating the average value of data in a current signal window, interference values in the acquired current data are reduced, a system response starting point and a system response ending point after disturbance injection are found out in the current signal data after filtering and denoising, and the time difference between the response starting point and the response ending point is calculated:
ΔT＝T I -T i
wherein T is I For the system response end point time, T i The time difference deltat is the system response time, which is the system response start point time.
The fault area comprises a plurality of subareas, the whole power system and each subarea have response time ranges, step response time in current sampling of subarea nodes in a disturbance process is separated, the structure of a power system network can be changed when early faults occur in the power system, the response speed of the power system can be obviously slowed down when the structure of the power system network is changed, and when the response speed in the power system after disturbance is injected is obviously greater than the intrinsic response speed of the power system, the early faults of insulation occur in the power system area.
S3: after the early fault area is identified, a trip instruction is sent to the circuit breaker through logic operation.
Specifically, when the response time in the power system area is detected to change, if the change range of the response change time exceeds a change time threshold, judging that an early fault occurs in the power system, checking the response time of a partition range in the power system, and issuing a tripping instruction to a partition with the increased response time to isolate the early fault in the partition; if the response time in the power system area is detected to change, but the change range of the response time does not exceed the change time threshold, judging that no early fault occurs in the power system, and not issuing a tripping instruction.
Further, the tripping instruction comprises that after judging that the power system has a fault result according to the change of the response time of the power system, the fault result is output, the fault partition in the power system is found out, the circuit breakers on the two sides of the fault partition are tripped, and the fault area is isolated before the early fault evolves into a permanent fault.
Example 2
Referring to fig. 2, an intelligent power distribution room dc line early fault location system is provided for a second embodiment of the present invention.
Specifically, the system comprises a data communication module, a data processing module and a logic execution module;
the data communication module is used for acquiring data of a monitoring system in the intelligent power distribution room and terminal power electronic equipment in the range of the intelligent power distribution room, and injecting an initiating instruction to each branch current and disturbance in the intelligent power distribution room;
the data processing module is used for solving the system response time, obtaining the system response time by using the filtered measurement result, and comparing the system response time with the normal system response time of the system to obtain an early fault area;
and the logic execution module is used for executing a tripping instruction on an early fault area when judging that the early fault of the area exists in the power system.
Example 3
Referring to fig. 3 to 5, for a third embodiment provided by the present invention, an early fault location method for a dc line of an intelligent power distribution room is provided, and in order to verify the beneficial effects of the present invention, scientific demonstration is performed through a simulation experiment, so as to verify the effectiveness of the method.
Specifically, a power system architecture as shown in fig. 2 is constructed, and an example network architecture as shown in fig. 3 is constructed.
Further, branch current measurement data are obtained, disturbance injection is initiated by the voltage type power electronic device in the voltage control loop, and a short-term step type signal with a constant value is superimposed on the voltage reference value.
In this embodiment, a step signal of 0.03pu with a duration of 100ms is used to construct an embodiment.
Because the early fault is equivalent to connecting a resistor with a larger resistance in parallel in the electric network, when the measured disturbance response time of the system is obviously larger than the intrinsic response speed of the system, the early fault of insulation of the area can be judged, and the system response time is indirectly obtained by adopting a mode of subtracting the trough time from the peak time of the measured result after filtering.
Referring to the comparison of fig. 5, it can be derived that there is a change in the system response time when an early failure occurs in the power system.
And judging an early fault area through the response time of the power system, outputting a fault result, tripping off the circuit breakers at two sides of the fault area, and isolating the fault area before the early fault evolves into a permanent fault.
Example 4
A fourth embodiment of the present invention, which is different from the previous embodiment, is:
the functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention may be embodied essentially or in a part contributing to the prior art or in a part of the technical solution, in the form of a software product stored in a storage medium, comprising several instructions for causing a computer device (which may be a personal computer, a server, a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-only memory (ROM), a random access memory (RAM, random Access Memory), a magnetic disk, or an optical disk, or other various media capable of storing program codes.
Logic and/or steps represented in the flowcharts or otherwise described herein, e.g., a ordered listing of executable instructions for implementing logical functions, can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device.
More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or more wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). In addition, the computer readable medium may even be paper or other suitable medium on which the program is printed, as the program may be electronically captured, via, for instance, optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner, if necessary, and then stored in a computer memory.
It is to be understood that portions of the present invention may be implemented in hardware, software, firmware, or a combination thereof. In the above-described embodiments, the various steps or methods may be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, may be implemented using any one or combination of the following techniques, as is well known in the art: discrete logic circuits having logic gates for implementing logic functions on data signals, application specific integrated circuits having suitable combinational logic gates, programmable Gate Arrays (PGAs), field Programmable Gate Arrays (FPGAs), and the like.
Furthermore, in an effort to provide a concise description of the exemplary embodiments, all features of an actual implementation may not be described (i.e., those not associated with the best mode presently contemplated for carrying out the invention, or those not associated with practicing the invention).
It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.
It should be noted that the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present invention may be modified or substituted without departing from the spirit and scope of the technical solution of the present invention, which is intended to be covered in the scope of the claims of the present invention.

Claims (10)

1. An intelligent power distribution room direct current line early fault positioning method is characterized in that: comprising the steps of (a) a step of,
acquiring data of a monitoring system in an intelligent power distribution room and terminal power electronic equipment in a governed range, and injecting an initiating instruction for current and disturbance injection of each branch in the intelligent power distribution room;
solving the system response time, obtaining the system response time by using the filtered measurement result, and comparing the system response time with the normal system response time of the system to obtain an early fault region;
after the early fault area is identified, a trip instruction is sent to the circuit breaker through logic operation.
2. The method for locating early faults of a direct current circuit of an intelligent power distribution room as claimed in claim 1, wherein the method comprises the following steps: the terminal power electronic equipment data comprise current data, voltage data and fluctuation amplitude data of current and voltage in a terminal monitoring system; the disturbance injection initiating instruction comprises an instruction for introducing a specific external disturbance signal into the power system, the system response time after the disturbance injection is recorded, and the response and stability of the power system are tested according to the recorded response time.
3. The method for locating early faults of a direct current circuit of an intelligent power distribution room as claimed in claim 2, wherein the method comprises the following steps: the disturbance injection initiating instruction further comprises that the disturbance injection selects power electronic equipment adopting voltage type control and is controlled in a voltage instruction u ref Superimposed disturbance injection value a in After entering the voltage control loop, obtaining a current instruction value I ref ：
I ref ＝G(s)[u ref +a in (u(t-t ins )-u(t-t end ))-u mea ]
Wherein G(s) is the transfer coefficient of the voltage outer loop, u (t-t) ins ) And u (t-t) end ) Respectively indicate the start t ins And end t end Step function of time, u mea Is the output voltage value.
4. An intelligent power distribution room dc line early fault locating method as claimed in claim 3, wherein: the response time of the solving system comprises the steps of monitoring current change in the power system by using a sensor after disturbance instructions are injected, collecting current data changed in the power system, and carrying out mean filtering denoising processing on the collected current data, wherein the mean filtering processing is as follows:
wherein y N is the denoised current signal sample, x N is the original current signal sample, and N is the window size;
noise is reduced by calculating the average value of data in a current signal window, interference values in the acquired current data are reduced, a system response starting point and a system response ending point after disturbance injection are found out in the current signal data after filtering and denoising, and the time difference between the response starting point and the response ending point is calculated:
ΔT＝T I -T i
wherein T is I For the system response end point time, T i The time difference deltat is the system response time, which is the system response start point time.
5. The method for locating early faults of a direct current circuit of an intelligent power distribution room as claimed in claim 4, wherein the method comprises the following steps: the fault area comprises a plurality of subareas, the whole power system and each subarea have response time ranges, step response time in current sampling of subarea nodes in a disturbance process is separated, the structure of a power system network can be changed when early faults occur in the power system, the response speed of the power system can be obviously slowed down when the structure of the power system network is changed, and when the response speed in the power system after disturbance is injected is obviously greater than the intrinsic response speed of the power system, the early faults of insulation occur in the power system area.
6. The method for locating early faults of direct current lines of an intelligent power distribution room according to claim 5, wherein the logic operation comprises the steps of judging that early faults occur in a power system when the response time in a power system area is detected to change, if the change range of the response time exceeds a change time threshold value, checking the response time of a subarea range in the power system, giving a tripping command to the subarea with the enlarged response time, and isolating the early faults in the subarea; if the response time in the power system area is detected to change, but the change range of the response time does not exceed the change time threshold, judging that no early fault occurs in the power system, and not issuing a tripping instruction.
7. The method for locating early faults of a direct current circuit of an intelligent power distribution room as claimed in claim 6, wherein the method comprises the following steps: the tripping instruction comprises that after judging the power system fault result according to the change of the response time of the power system, the power system outputs the fault result, the fault partition in the power system is found out, the circuit breakers on the two sides of the fault partition are tripped, and the fault area is isolated before the early fault evolves into a permanent fault.
8. A system employing an intelligent distribution room dc line early fault locating method as claimed in any one of claims 1 to 7, wherein: the system comprises a data communication module, a data processing module and a logic execution module;
the data communication module is used for acquiring data of a monitoring system in the intelligent power distribution room and terminal power electronic equipment in the range of the intelligent power distribution room, and injecting an initiating instruction to each branch current and disturbance in the intelligent power distribution room;
the data processing module is used for solving the system response time, obtaining the system response time by using the filtered measurement result, and comparing the system response time with the normal system response time of the system to obtain an early fault area;
and the logic execution module is used for executing a tripping instruction on an early fault area when judging that the early fault of the area exists in the power system.
9. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor, when executing the computer program, implements the steps of a method for locating early faults in a direct current line of an intelligent power distribution room as claimed in any one of claims 1 to 7.
10. A computer readable storage medium having stored thereon a computer program, characterized in that the computer program when executed by a processor implements the steps of a method for early fault localization of a direct current line of an intelligent power distribution room as claimed in any one of claims 1 to 7.
CN202311024557.4A 2023-08-15 2023-08-15 Early fault positioning method and system for direct-current line of intelligent power distribution room Pending CN117330884A (en)

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