CN115308541A - Insulation fault judgment method and device for low-voltage alternating-current long cable - Google Patents
Insulation fault judgment method and device for low-voltage alternating-current long cable Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials
- G01R31/1263—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation
- G01R31/1272—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation of cable, line or wire insulation, e.g. using partial discharge measurements
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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
- G01R31/086—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution networks, i.e. with interconnected conductors
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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
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
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- 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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Abstract
The application provides a method and a device for judging insulation faults of a low-voltage alternating-current long cable, which relate to the field of power equipment fault detection and comprise the following steps: determining the maximum current error threshold value of each long cable according to the obtained residual current value of each long cable in the transformer station area; determining a corresponding residual current correction coefficient according to the characteristic parameters of the long cable; determining a real-time residual current value of the long cable according to the residual current correction coefficient and the residual current value; and judging whether the long cable has an insulation fault or not according to the real-time residual current value and the maximum current error threshold value. This application can monitor the residual current of low pressure long cable to judge it and whether have insulation fault.
Description
Technical Field
The application relates to the field of power equipment fault detection, in particular to a method and a device for judging insulation faults of a low-voltage alternating-current long cable.
Background
The reasons for fire caused by the cable fault of the alternating current system for the transformer substation can be generally divided into metal short circuit and insulation damage. If a fire disaster caused by metal short circuit occurs, protection can be carried out through short circuit protection; if the fire that cable insulation damage arouses, because the existence of creepage arc impedance, arc fault current is less, can't protect through traditional short-circuit protection. In the current industry standard, the residual current monitoring device is recommended to be used for electric fire protection, but at present, the residual current monitoring device is mostly used in the industrial and civil building field, and no mature monitoring means exists in an alternating current system for a low-voltage station.
Disclosure of Invention
The method and the device for judging the insulation fault of the low-voltage alternating-current long cable can monitor the residual current of the low-voltage alternating-current long cable so as to judge whether the insulation fault exists.
In order to solve the technical problem, the application provides the following technical scheme:
in a first aspect, the present application provides a method for determining an insulation fault of a low-voltage ac long cable, including:
determining the maximum current error threshold value of each long cable according to the obtained residual current value of each long cable in the transformer station area;
determining a corresponding residual current correction coefficient according to the characteristic parameters of the long cable;
determining a real-time residual current value of the long cable according to the residual current correction coefficient and the residual current value;
and judging whether the long cable has an insulation fault or not according to the real-time residual current value and the maximum current error threshold value.
Further, the step of obtaining the background mean value of the residual current in the transformer station area comprises:
determining corresponding weight according to the operation load value of each long cable;
and determining a background mean value of the residual current according to the weight and the residual current value.
Further, the characteristic parameters include: the voltage grade of the transformer substation, the length of the long cable, the historical operation fault frequency and the historical operation age limit; the determining of the corresponding residual current correction coefficient according to the characteristic parameters of the long cable comprises:
determining the importance degree of the long cable according to the voltage grade of the transformer substation;
determining the influence range of the long cable according to the length of the long cable;
and determining the residual current correction coefficient according to the historical operation failure times, the historical operation age, the importance degree and the influence range of the long cable.
Further, the residual current values include: the vector numerical value of the head end of the cable and the vector numerical value of the tail end of the cable; the determining the real-time residual current value of the long cable according to the residual current correction coefficient and the residual current value comprises the following steps:
determining the vector sum of the residual current according to the vector numerical value of the head end of the cable and the vector numerical value of the tail end of the cable;
determining the vector difference of the residual current according to the vector sum of the residual current and the background mean value of the residual current;
and determining the real-time residual current value according to the vector difference of the residual current and the residual current correction coefficient.
Further, the determining whether the long cable has an insulation fault according to the real-time residual current value and the maximum current error threshold value includes:
when the real-time residual current value is larger than the maximum current error threshold value, determining that the long cable has the insulation fault;
and when the real-time residual current value is less than or equal to the maximum current error threshold value, determining that the insulation fault does not exist in the long cable.
In a second aspect, the present application provides an insulation fault determination device for a low-voltage ac long cable, comprising:
the error threshold value determining unit is used for determining the maximum current error threshold value of each long cable according to the obtained residual current value of each long cable in the transformer station area;
the correction coefficient determining unit is used for determining a corresponding residual current correction coefficient according to the characteristic parameters of the long cable;
the real-time current determining unit is used for determining a real-time residual current value of the long cable according to the residual current correction coefficient and the residual current value;
and the fault judgment unit is used for judging whether the long cable has an insulation fault according to the real-time residual current value and the maximum current error threshold value.
Further, the insulation fault determination device for the low-voltage ac long cable further comprises:
the load weight determining unit is used for determining corresponding weight according to the running load value of each long cable;
and the background mean value determining unit is used for determining the background mean value of the residual current according to the weight and the residual current value.
Further, the correction coefficient determination unit includes:
the importance degree determining module is used for determining the importance degree of the long cable according to the voltage grade of the transformer substation;
the influence range determining module is used for determining the influence range of the long cable according to the length of the long cable;
and the correction coefficient determining module is used for determining the residual current correction coefficient according to the historical operation failure frequency, the historical operation age, the importance degree and the influence range of the long cable.
Further, the residual current values include: the vector numerical value of the head end of the cable and the vector numerical value of the tail end of the cable; the real-time current determination unit includes:
the vector sum determining module is used for determining the vector sum of the residual current according to the vector numerical value of the head end of the cable and the vector numerical value of the tail end of the cable;
the vector difference determining module is used for determining the vector difference of the residual current according to the vector sum of the residual current and the background mean value of the residual current;
and the real-time current determining module is used for determining the real-time residual current value according to the vector difference of the residual current and the residual current correction coefficient.
Further, the failure determination unit includes:
the fault determination module is used for determining that the insulation fault exists in the long cable when the real-time residual current value is larger than the maximum current error threshold value;
and the fault elimination module is used for determining that the long cable has no insulation fault when the real-time residual current value is less than or equal to the maximum current error threshold value.
In a third aspect, the present application provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor, where the processor implements the steps of the method for determining an insulation fault of a low-voltage ac long cable when executing the program.
In a fourth aspect, the present application provides a computer-readable storage medium having stored thereon a computer program which, when being executed by a processor, realizes the steps of the insulation fault determination method for a long, low-voltage ac cable.
In a fifth aspect, the present application provides a computer program product comprising computer programs/instructions which, when executed by a processor, perform the steps of the method for insulation fault determination of a long low voltage ac cable.
Aiming at the problems in the prior art, the method and the device for judging the insulation fault of the low-voltage alternating-current long cable can be used for calculating the residual current of the low-voltage alternating-current long cable by combining the factors such as the background mean value of the residual current of a transformer substation, the voltage grade, the length of the long cable, the historical operation fault frequency, the historical operation age limit and the like, effectively monitoring the operation state of the alternating-current cable of the transformer substation, timely finding out a fault line when the long cable in the transformer substation has the insulation fault, and ensuring the operation safety of a low-voltage system for the substation.
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, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a flowchart of a method for determining an insulation fault of a low-voltage ac long cable according to an embodiment of the present application;
fig. 2 is a second flowchart of a method for determining an insulation fault of a low-voltage ac long cable according to an embodiment of the present application;
FIG. 3 is a flow chart of determining a residual current correction factor in an embodiment of the present application;
FIG. 4 is a flow chart of determining a real-time residual current value according to an embodiment of the present application;
FIG. 5 is a flowchart illustrating an embodiment of the present invention for determining an insulation fault;
fig. 6 is one of the structural diagrams of an insulation fault determination apparatus of a low-voltage ac long cable in the embodiment of the present application;
fig. 7 is a second structural diagram of an insulation fault determination apparatus for a low-voltage ac long cable according to an embodiment of the present application;
fig. 8 is a structural diagram of a correction coefficient determination unit in the embodiment of the present application;
FIG. 9 is a block diagram of a real-time current determination unit in an embodiment of the present application;
fig. 10 is a structural diagram of a failure determination unit in the embodiment of the present application;
fig. 11 is a schematic structural diagram of an electronic device in an embodiment of the present application;
fig. 12 is a wiring diagram of a residual current detection device of an ac system for a substation in an embodiment of the present application;
fig. 13 is a data diagram of a monitoring device according to an embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without making any creative effort belong to the protection scope of the present application.
In one embodiment, referring to fig. 1, in order to monitor a residual current of a long low-voltage ac cable and determine whether an insulation fault exists, the present application provides an insulation fault determining method for a long low-voltage ac cable, including:
s101: determining the maximum current error threshold value of each long cable according to the obtained residual current value and the obtained residual current background mean value of each long cable in the transformer station area;
it can be understood that, in order to determine the maximum current error threshold of each long cable, it is first required to obtain a background mean value of residual currents in a substation area, and referring to fig. 2, the specific steps include: determining corresponding weights according to the operation load values of the long cables (S201); and determining the background mean value of the residual current according to the weight and the value of the residual current (S202).
In practice, the low voltage in the area of power station is changedBackground residual current is present in an alternating current cable (also called a long cable) during normal operation. This value will fluctuate widely as the line load changes. These fluctuations interfere with the determination of the insulation state of the cable (whether or not an insulation fault is present), and therefore, the background current value of each long cable should be checked first. In engineering, CT monitoring devices can be arranged at the head end and the tail end of each long cable, and the background value I of the residual current of each long cable at each time of normal operation can be obtained through measurement 1 ，I 2 ，........I N . Wherein, I n The value of the background current of the nth long cable is shown, and the value can be generally the average value of the values measured by arranging CT monitoring devices at the first end and the last end of the cable, wherein N =1 \8230; N.
And then the weighting p is carried out by combining the current line load current or the in-station operation load.
If the load supplied by the line is an important load, selecting p as 1.2; for a heavier load, p is selected to be 1.1; the normal load is 1.
Obtaining the background mean value I of the residual current of each long cable in the transformer (power generation) station area 0 。
According to a calculation formula
σ＝|I n -I 0 | (2)
And solving the maximum error value sigma between the residual current background value of each long cable and the residual current background mean value.
S102: determining a corresponding residual current correction coefficient according to the characteristic parameters of the long cable;
in specific implementation, referring to fig. 3, the characteristic parameters include: the voltage grade of the transformer substation, the length of the long cable, the historical operation fault frequency and the historical operation age limit; the determining of the corresponding residual current correction coefficient according to the characteristic parameters of the long cable comprises:
s301: determining the importance degree of the long cable according to the voltage grade of the transformer substation;
s302: determining the influence range of the long cable according to the length of the long cable;
s303: and determining the residual current correction coefficient according to the historical operation failure times, the historical operation age, the importance degree and the influence range of the long cable.
It can be understood that the operating conditions and the surrounding environment are different for different lengths of cable. These differences can affect the residual current monitoring of the cable. In the embodiment of the application, the operation states of the long cables can be divided, and the weight can be determined. And determining a residual current correction coefficient by combining the aspects of the running mode, the region, the load current, the fault probability and the like of the long cable.
In the formula (I), the compound is shown in the specification,
a1 is the importance of the substation where the long cable is located. The division can be made according to the voltage class of the substation. In one embodiment, the value ranges are as follows: 0.6 at 500kV or above, 0.5 at 220kV and 0.4 at 110kV or below;
a2 is the range of influence of a long cable. The division may be made according to the cable length. In one embodiment, the value ranges are as follows: the length is more than 300m and is 0.65, 300m to 200m is 0.55, 200m to 150m is 0.5, and less than 150m is 0.45;
B m is a historical case of long cables. The division can be made according to historical failure conditions (several failures have occurred historically). In one embodiment, the number of cable faults occurring in the substation every year in the last 10 years can be counted. If no fault occurs in the year, recording as 0; if the fault occurs in the year, recording as 0.05; if the fault occurs more than once in the year, the number is recorded as 0.08, and the counting summation is carried out on the last 10 years.
And C is the operating life condition of the long cable. In one embodiment, when the cable with the operation age of more than 10 years takes on a value of 0.98, the cable with the operation age of 10 years to 5 years takes on a value of 0.99, and the cable with the operation age of less than 5 years takes on a value of 1.
S103: determining a real-time residual current value of the long cable according to the residual current correction coefficient, the residual current background mean value and the residual current value;
in one embodiment, referring to fig. 4, the residual current values include: the vector numerical value of the head end of the cable and the vector numerical value of the tail end of the cable; the determining the real-time residual current value of the long cable according to the residual current correction coefficient and the residual current value comprises the following steps:
s401: determining the vector sum of the residual currents according to the vector numerical values of the head end of the cable and the vector numerical values of the tail end of the cable;
s402: determining the vector difference of the residual current according to the vector sum of the residual current and the background mean value of the residual current;
s403: and determining the real-time residual current value according to the vector difference of the residual current and the residual current correction coefficient.
It can be understood that residual current monitoring devices are installed at two ends of a long cable, and are respectively connected to the A-phase, B-phase, C-phase and N-phase cables through monitoring CT (computed tomography) measuring pliers to monitor residual currents at two ends of the long cable and obtain a head-end residual current vector I A 、I B . Calculating in the residual current detection slave device according to a calculation formula
Obtaining the real-time residual current value of each long cable
Wherein, the first and the second end of the pipe are connected with each other,
may be considered as the actual measured real-time residual current value.
S104: and judging whether the long cable has an insulation fault or not according to the real-time residual current value and the maximum current error threshold value.
In an embodiment, referring to fig. 5, the determining whether there is an insulation fault in the long cable according to the real-time residual current value and the maximum current error threshold includes:
s501: comparing the real-time residual current value with the maximum current error threshold value, and determining that the insulation fault exists in the long cable when the real-time residual current value is larger than the maximum current error threshold value;
s502: and comparing the real-time residual current value with the maximum current error threshold value, and determining that the long cable has no insulation fault when the real-time residual current value is less than or equal to the maximum current error threshold value.
It will be appreciated that the determination is made as to the value of the residual current. Under normal operating conditions (i.e. when no insulation fault occurs)
The value should be less than or equal to the maximum error σ, i.e.
When the cable insulation is damaged, fault current flows into the ground and does not flow through the N line, and unbalanced current, namely residual current exceeds the maximum error, namely
After the judgment, the cable state can be monitored and displayed in a centralized way:
and according to the judgment result, displaying the running state of the cable at the centralized monitoring position, and displaying the residual current value. By means of a pre-warning value alpha, t set in advance 1 And an alarm value beta, t 2 And comparing and judging the running state of the cable. When the temperature is higher than the set temperature
And the duration t is more than or equal to t 1 When the cable is detected, a pre-warning signal is sent out to prompt a worker to carry out cable inspection; when in use
And the duration t is more than or equal to t 2 And sending an alarm signal, and making emergency preparation work by the staff. In general, α and β are both greater than σ.
From the above description, the method for judging the insulation fault of the low-voltage alternating-current long cable can be used for calculating the residual current of the low-voltage alternating-current long cable and effectively monitoring the operation state of the alternating-current cable of the transformer substation by combining the factors such as the background mean value of the residual current, the voltage grade, the length of the long cable, the number of times of historical operation faults and the historical operation age of the transformer substation, and can be used for timely finding out a fault line when the long cable in the transformer substation has the insulation fault and ensuring the operation safety of a low-voltage system for the transformer substation.
To better illustrate the methods and apparatus provided herein, specific embodiments of the present application are described below with reference to the accompanying drawings.
(1) Checking background mean value of residual current in substation
Referring to fig. 12, the background value of the 24h residual current is shown in the following table, taking the low-voltage ac 35KV switch cabinet electric heating power cable as an example.
The weight of the residual current at each moment is divided according to the load polarity, in this example, the total load current ratio.
The average load current is 397.833A, and the specific gravity is 340/397.83=0.855 in 0h as an example.
According to the formulas (1) and (2), the background mean value of the residual current can be calculated as follows:
the maximum deviation value is:
σ＝|21-15.25|＝5.75mA
(2) calculating the residual current correction coefficient
The basic information of the transformer substation and the cable is as follows:
obtained according to the formula (3)
(3) CT monitoring device measures
And (2) taking the background value of the residual current of the cable measured in the step (1) within 24h as a reference, and carrying out residual current monitoring work of a CT monitoring device, wherein the measurement data are shown in figure 13, wherein the maximum value is 20mA, and the minimum value is 11mA.
According to the formula (4), the maximum value of the actual residual current can be calculated as
i. Background data determination
According to the judgment, it can know
The cable is in a normal operating state.
Centralized monitoring and displaying cable status
Setting a pre-warning value alpha, t 1 And an alarm value beta, t 2 5mA and 10s respectively; 40mA,10s. Due to the fact that
The centralized monitoring shows that the cable is in a normal running state and no alarm is given.
Based on the same inventive concept, the embodiment of the present application further provides an insulation fault determination apparatus for a low-voltage ac long cable, which can be used to implement the method described in the above embodiment, as described in the following embodiment. Because the principle of solving the problems of the insulation fault judgment device of the low-voltage alternating-current long cable is similar to that of the insulation fault judgment method of the low-voltage alternating-current long cable, the implementation of the insulation fault judgment device of the low-voltage alternating-current long cable can refer to the implementation of a software performance reference determination method, and repeated parts are not described again. As used hereinafter, the term "unit" or "module" may be a combination of software and/or hardware that implements a predetermined function. While the system described in the embodiments below is preferably implemented in software, implementations in hardware, or a combination of software and hardware are also possible and contemplated.
In one embodiment, referring to fig. 6, in order to monitor a residual current of a low-voltage ac long cable and determine whether an insulation fault exists, the present application provides an insulation fault determining apparatus for a low-voltage ac long cable, including: an error threshold determination unit 601, a correction coefficient determination unit 602, a real-time current determination unit 603, and a fault determination unit 604.
An error threshold determining unit 601, configured to determine a maximum current error threshold of each long cable according to the obtained residual current value of each long cable in the substation area;
a correction coefficient determining unit 602, configured to determine a corresponding residual current correction coefficient according to the characteristic parameter of the long cable;
a real-time current determining unit 603, configured to determine a real-time residual current value of the long cable according to the residual current correction coefficient and the residual current value;
and a fault judgment unit 604, configured to judge whether there is an insulation fault in the long cable according to the real-time residual current value and the maximum current error threshold.
In one embodiment, referring to fig. 7, the insulation fault determination apparatus for a low-voltage ac long cable further includes: load weight determination section 701 and background mean value determination section 702.
A load weight determining unit 701, configured to determine a corresponding weight according to the operation load value of each long cable;
a background mean value determining unit 702, configured to determine a background mean value of the residual current according to the weight and the residual current value.
In an embodiment, referring to fig. 8, the correction factor determining unit 602 includes: an importance level determination module 801, an influence range determination module 802, and a correction coefficient determination module 803.
An importance level determining module 801, configured to determine an importance level of the long cable according to the voltage class of the substation;
an influence range determining module 802, configured to determine an influence range of the long cable according to the length of the long cable;
and a correction coefficient determining module 803, configured to determine the residual current correction coefficient according to the historical operation failure frequency, the historical operation age, the importance level, and the influence range of the long cable.
In one embodiment, referring to fig. 9, the residual current values include: the vector numerical value of the head end of the cable and the vector numerical value of the tail end of the cable; the real-time current determining unit 603 includes: vector sum determination module 901, vector difference determination module 902, and real-time current determination module 903.
A vector sum determining module 901, configured to determine a vector sum of residual currents according to the cable head end vector numerical value and the cable tail end vector numerical value;
a vector difference determining module 902, configured to determine a vector difference of a residual current according to the vector sum of the residual current and the background mean value of the residual current;
and a real-time current determining module 903, configured to determine the real-time residual current value according to the vector difference of the residual current and the residual current correction coefficient.
In an embodiment, referring to fig. 10, the failure determining unit 604 includes: a fault determination module 1001 and a fault clearance module 1002.
A fault determining module 1001, configured to determine that the insulation fault exists in the long cable when the real-time residual current value is greater than the maximum current error threshold;
a troubleshooting module 1002, configured to determine that the insulation fault does not exist in the long cable when the real-time residual current value is less than or equal to the maximum current error threshold.
In terms of hardware, in order to monitor a residual current of a long low-voltage ac cable and determine whether an insulation fault exists, the present application provides an embodiment of an electronic device for implementing all or part of contents in a method for determining an insulation fault of a long low-voltage ac cable, where the electronic device specifically includes the following contents:
a Processor (Processor), a Memory (Memory), a communication Interface (Communications Interface) and a bus; the processor, the memory and the communication interface complete mutual communication through the bus; the communication interface is used for realizing information transmission between the insulation fault judgment device of the low-voltage alternating-current long cable and relevant equipment such as a core service system, a user terminal, a relevant database and the like; the logic controller may be a desktop computer, a tablet computer, a mobile terminal, and the like, but the embodiment is not limited thereto. In this embodiment, the logic controller may refer to an embodiment of the method for determining an insulation fault of a low-voltage ac long cable and an embodiment of the apparatus for determining an insulation fault of a low-voltage ac long cable in the embodiments, and the contents thereof are incorporated herein, and repeated details are not repeated herein.
It is understood that the user terminal may include a smart phone, a tablet electronic device, a network set-top box, a portable computer, a desktop computer, a Personal Digital Assistant (PDA), a vehicle-mounted device, a smart wearable device, and the like. Wherein, intelligence wearing equipment can include intelligent glasses, intelligent wrist-watch, intelligent bracelet etc..
In practical applications, part of the insulation fault determination method for the long low-voltage ac cable may be performed on the electronic device side as described above, or all operations may be performed in the client device. The selection may be specifically performed according to the processing capability of the client device, the limitation of the user usage scenario, and the like. This is not a limitation of the present application. The client device may further include a processor if all operations are performed in the client device.
The client device may have a communication module (i.e., a communication unit), and may be in communication connection with a remote server to implement data transmission with the server. The server may include a server on the side of the task scheduling center, and in other implementation scenarios, the server may also include a server on an intermediate platform, for example, a server on a third-party server platform that is communicatively linked to the task scheduling center server. The server may include a single computer device, or may include a server cluster formed by a plurality of servers, or a server structure of a distributed apparatus.
Fig. 11 is a schematic block diagram of a system configuration of an electronic device 9600 according to an embodiment of the present application. As shown in fig. 11, the electronic device 9600 can include a central processor 9100 and a memory 9140; the memory 9140 is coupled to the central processor 9100. It is noted that this FIG. 11 is exemplary; other types of structures may also be used in addition to or in place of the structures to implement telecommunications or other functions.
In one embodiment, the function of the insulation fault determination method for the low-voltage ac long cable may be integrated into the central processor 9100. The central processor 9100 may be configured to control as follows:
s101: determining the maximum current error threshold value of each long cable according to the obtained residual current value and the obtained residual current background mean value of each long cable in the transformer station area;
s102: determining a corresponding residual current correction coefficient according to the characteristic parameters of the long cable;
s103: determining a real-time residual current value of the long cable according to the residual current correction coefficient, the residual current background mean value and the residual current value;
s104: and judging whether the long cable has an insulation fault or not according to the real-time residual current value and the maximum current error threshold value.
From the above description, the method for judging the insulation fault of the low-voltage alternating-current long cable can be used for calculating the residual current of the low-voltage alternating-current long cable and effectively monitoring the operation state of the alternating-current cable of the transformer substation by combining the factors such as the background mean value of the residual current, the voltage grade, the length of the long cable, the number of times of historical operation faults and the historical operation age of the transformer substation, and can be used for timely finding out a fault line when the long cable in the transformer substation has the insulation fault and ensuring the operation safety of a low-voltage system for the transformer substation.
In another embodiment, the insulation fault determination device of the low-voltage ac long cable may be configured separately from the central processing unit 9100, for example, the insulation fault determination device of the low-voltage ac long cable of the data composite transmission device may be configured as a chip connected to the central processing unit 9100, and the function of the insulation fault determination method of the low-voltage ac long cable is implemented by the control of the central processing unit.
As shown in fig. 11, the electronic device 9600 may further include: a communication module 9110, an input unit 9120, an audio processor 9130, a display 9160, and a power supply 9170. It is noted that the electronic device 9600 also does not necessarily include all of the components shown in fig. 11; in addition, the electronic device 9600 may further include components not shown in fig. 11, which may be referred to in the prior art.
As shown in fig. 11, a central processor 9100, sometimes referred to as a controller or operational control, can include a microprocessor or other processor device and/or logic device, which central processor 9100 receives input and controls the operation of the various components of the electronic device 9600.
The memory 9140 can be, for example, one or more of a buffer, a flash memory, a hard drive, a removable media, a volatile memory, a non-volatile memory, or other suitable device. The information relating to the failure may be stored, and a program for executing the information may be stored. And the central processing unit 9100 can execute the program stored in the memory 9140 to realize information storage or processing, or the like.
The input unit 9120 provides input to the central processor 9100. The input unit 9120 is, for example, a key or a touch input device. Power supply 9170 is used to provide power to electronic device 9600. The display 9160 is used for displaying display objects such as images and characters. The display may be, for example, an LCD display, but is not limited thereto.
The memory 9140 can be a solid state memory, e.g., read Only Memory (ROM), random Access Memory (RAM), a SIM card, or the like. There may also be a memory that holds information even when power is off, can be selectively erased, and is provided with more data, an example of which is sometimes called an EPROM or the like. The memory 9140 could also be some other type of device. Memory 9140 includes a buffer memory 9141 (sometimes referred to as a buffer). The memory 9140 may include an application/function storage portion 9142, the application/function storage portion 9142 being used for storing application programs and function programs or for executing a flow of operations of the electronic device 9600 by the central processor 9100.
The memory 9140 can also include a data store 9143, the data store 9143 being used to store data, such as contacts, digital data, pictures, sounds, and/or any other data used by an electronic device. The driver storage portion 9144 of the memory 9140 may include various drivers of the electronic device for communication functions and/or for performing other functions of the electronic device (e.g., messaging applications, contact book applications, etc.).
The communication module 9110 is a transmitter/receiver 9110 that transmits and receives signals via an antenna 9111. The communication module (transmitter/receiver) 9110 is coupled to the central processor 9100 to provide input signals and receive output signals, which may be the same as in the case of a conventional mobile communication terminal.
Based on different communication technologies, a plurality of communication modules 9110, such as a cellular network module, a bluetooth module, and/or a wireless lan module, may be disposed in the same electronic device. The communication module (transmitter/receiver) 9110 is also coupled to a speaker 9131 and a microphone 9132 via an audio processor 9130 to provide audio output via the speaker 9131 and receive audio input from the microphone 9132, thereby implementing ordinary telecommunication functions. The audio processor 9130 may include any suitable buffers, decoders, amplifiers and so forth. In addition, the audio processor 9130 is also coupled to the central processor 9100, thereby enabling recording locally through the microphone 9132 and enabling locally stored sounds to be played through the speaker 9131.
An embodiment of the present application further provides a computer-readable storage medium capable of implementing all the steps in the method for determining an insulation fault of a low-voltage ac long cable with a server or a client as an execution subject in the foregoing embodiments, where the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the computer program implements all the steps in the method for determining an insulation fault of a low-voltage ac long cable with a server or a client as an execution subject, for example, when the processor executes the computer program, the processor implements the following steps:
s101: determining the maximum current error threshold value of each long cable according to the obtained residual current value and the obtained residual current background mean value of each long cable in the transformer station area;
s102: determining a corresponding residual current correction coefficient according to the characteristic parameters of the long cable;
s103: determining a real-time residual current value of the long cable according to the residual current correction coefficient, the residual current background mean value and the residual current value;
s104: and judging whether the long cable has an insulation fault or not according to the real-time residual current value and the maximum current error threshold value.
From the above description, the method for judging the insulation fault of the low-voltage alternating-current long cable can be used for calculating the residual current of the low-voltage alternating-current long cable and effectively monitoring the operation state of the alternating-current cable of the transformer substation by combining the factors such as the background mean value of the residual current, the voltage grade, the length of the long cable, the number of times of historical operation faults and the historical operation age of the transformer substation, and can be used for timely finding out a fault line when the long cable in the transformer substation has the insulation fault and ensuring the operation safety of a low-voltage system for the transformer substation.
As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, apparatus, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (devices), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The principle and the implementation mode of the invention are explained by applying specific embodiments in the invention, and the description of the embodiments is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.
Claims (15)
1. A method for judging insulation fault of a low-voltage alternating-current long cable is characterized by comprising the following steps:
determining a maximum current error threshold value of a long cable according to the obtained residual current value of the long cable in the transformer substation area;
determining a real-time residual current value of the long cable according to the characteristic parameters of the long cable and the residual current value;
and judging whether the long cable has an insulation fault or not according to the real-time residual current value and the maximum current error threshold value.
2. The method for determining an insulation fault of a long low-voltage alternating-current cable according to claim 1, wherein the step of determining a real-time residual current value of the long cable according to the characteristic parameters of the long cable and the residual current value comprises the following steps:
determining a corresponding residual current correction coefficient according to the characteristic parameters of the long cable;
and determining the real-time residual current value of the long cable according to the residual current correction coefficient and the residual current value.
3. The method for determining the insulation fault of the low-voltage alternating-current long cable according to claim 2, further comprising:
determining corresponding weight according to the operation load value of each long cable;
and determining a background mean value of the residual current according to the weight and the value of the residual current.
4. The method for judging the insulation fault of the low-voltage alternating-current long cable according to claim 3, wherein the characteristic parameters comprise: the voltage grade of the transformer substation, the length of the long cable, the historical operation fault frequency and the historical operation age limit; the determining of the corresponding residual current correction coefficient according to the characteristic parameters of the long cable comprises:
determining the importance degree of the long cable according to the voltage grade;
determining the influence range of the long cable according to the length;
and determining the residual current correction coefficient according to the historical operation fault frequency, the historical operation age, the importance degree and the influence range.
5. The method for judging the insulation fault of the low-voltage alternating-current long cable according to claim 4, wherein the residual current value comprises the following steps: the vector numerical value of the head end of the cable and the vector numerical value of the tail end of the cable; the determining of the real-time residual current value of the long cable according to the residual current correction coefficient and the residual current value comprises:
determining the vector sum of the residual current according to the vector numerical value of the head end of the cable and the vector numerical value of the tail end of the cable;
determining the vector difference of the residual current according to the vector sum of the residual current and the background mean value of the residual current;
and determining the real-time residual current value according to the vector difference of the residual current and the residual current correction coefficient.
6. The method for determining the insulation fault of the long low-voltage alternating-current cable according to claim 1, wherein the step of determining whether the long cable has the insulation fault according to the real-time residual current value and the maximum current error threshold value comprises:
comparing the real-time residual current value with the maximum current error threshold value, wherein if the real-time residual current value is larger than the maximum current error threshold value, the long cable has the insulation fault;
and comparing the real-time residual current value with the maximum current error threshold value, wherein if the real-time residual current value is less than or equal to the maximum current error threshold value, the long cable does not have the insulation fault.
7. An insulation fault judgment device of a low-voltage alternating-current long cable is characterized by comprising:
the error threshold value determining unit is used for determining the maximum current error threshold value of the long cable according to the obtained residual current value of the long cable in the transformer substation area;
the residual current determining unit is used for determining a real-time residual current value of the long cable according to the characteristic parameters of the long cable and the residual current value;
and the fault judgment unit is used for judging whether the long cable has an insulation fault according to the real-time residual current value and the maximum current error threshold value.
8. The insulation failure diagnosis device for a low-voltage ac long cable according to claim 7, wherein the residual current determination unit comprises:
the correction coefficient determining module is used for determining a corresponding residual current correction coefficient according to the characteristic parameters of the long cable;
and the real-time current determining module is used for determining the real-time residual current value of the long cable according to the residual current correction coefficient and the residual current value.
9. The apparatus for determining an insulation failure of a low-voltage ac long cable according to claim 7, further comprising:
the load weight determining unit is used for determining corresponding weight according to the running load value of each long cable;
and the background mean value determining unit is used for determining the background mean value of the residual current according to the weight and the residual current value.
10. The apparatus according to claim 8, wherein the characteristic parameters include: the voltage grade of the transformer substation, the length of the long cable, the historical operation fault frequency and the historical operation age limit; the correction coefficient determining module comprises:
the importance degree determining submodule is used for determining the importance degree of the long cable according to the voltage grade;
the influence range determining submodule is used for determining the influence range of the long cable according to the length;
and the correction coefficient determining submodule is used for determining the residual current correction coefficient according to the historical operation failure frequency, the historical operation age, the importance degree and the influence range.
11. The apparatus for determining insulation failure of low-voltage ac long cable according to claim 10, wherein the residual current value comprises: the vector value of the head end of the cable and the vector value of the tail end of the cable; the real-time current determination unit comprises:
the vector sum determining module is used for determining the vector sum of residual current according to the vector numerical value of the head end of the cable and the vector numerical value of the tail end of the cable;
the vector difference determining module is used for determining the vector difference of the residual current according to the vector sum of the residual current and the background mean value of the residual current;
and the real-time current determining module is used for determining the real-time residual current value according to the vector difference of the residual current and the residual current correction coefficient.
12. The insulation fault diagnosis apparatus for a low voltage ac long cable according to claim 7, wherein the fault diagnosis unit includes:
the fault determination module is used for comparing the real-time residual current value with the maximum current error threshold value, and if the real-time residual current value is larger than the maximum current error threshold value, the long cable has the insulation fault;
and the fault elimination module is used for comparing the real-time residual current value with the maximum current error threshold value, and if the real-time residual current value is less than or equal to the maximum current error threshold value, the long cable does not have the insulation fault.
13. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor implements the steps of the method for insulation fault determination of a low voltage ac long cable according to any one of claims 1 to 6 when executing the program.
14. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method for insulation fault diagnosis of a long low voltage alternating current cable according to any one of claims 1 to 5.
15. A computer program product comprising computer programs/instructions, characterized in that the computer programs/instructions, when executed by a processor, implement the steps of the method for insulation fault diagnosis of long low voltage ac cables according to any of claims 1 to 6.
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| CN202210917845.1A CN115308541A (en) | 2022-08-01 | 2022-08-01 | Insulation fault judgment method and device for low-voltage alternating-current long cable |
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| CN202210917845.1A CN115308541A (en) | 2022-08-01 | 2022-08-01 | Insulation fault judgment method and device for low-voltage alternating-current long cable |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117214587A (en) * | 2023-11-07 | 2023-12-12 | 国网浙江省电力有限公司象山县供电公司 | Detection method and detection system for cable equipment |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117214587A (en) * | 2023-11-07 | 2023-12-12 | 国网浙江省电力有限公司象山县供电公司 | Detection method and detection system for cable equipment |
| CN117214587B (en) * | 2023-11-07 | 2024-03-29 | 国网浙江省电力有限公司象山县供电公司 | Detection method and detection system for cable equipment |
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