CN112666490A - Method and device for rapidly detecting multipoint ground fault of direct current system - Google Patents
Method and device for rapidly detecting multipoint ground fault of direct current system Download PDFInfo
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- 238000010617 multipoint ground Methods 0.000 title claims abstract description 29
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- 239000011159 matrix material Substances 0.000 claims abstract description 66
- 238000001514 detection method Methods 0.000 claims abstract description 18
- 230000008030 elimination Effects 0.000 claims description 18
- 238000003379 elimination reaction Methods 0.000 claims description 18
- 238000009413 insulation Methods 0.000 description 4
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Abstract
The invention discloses a method and a device for rapidly detecting multipoint ground faults of a direct current system, wherein the method comprises the following steps: determining key nodes of N branches in a direct current system loop, and correspondingly installing a detection sensor terminal at each key node to form an NxN matrix L for describing the branches; considering system interference, setting a difference flow threshold value, constructing a difference flow description matrix D, if the difference flow of the ith branch exceeds the difference flow threshold value, setting 1 to the ith row and ith column element of the NxN dimension difference flow description matrix D, and otherwise, setting 0 to other elements of the difference flow description matrix D, wherein the ith row and ith column element of the NxN dimension difference flow description matrix D are all set to 0; multiplying the matrix L by a difference flow description matrix D to obtain a fault judgment matrix F ═ F (L × D) ═ F (F '), wherein F represents output misjudgment removal operation, and F' represents a variable of the output misjudgment removal operation; the invention has the advantages that: the branch circuits and the fault of the branch circuits are described in a matrix mode, and the multipoint ground fault of the direct current system can be quickly judged and found out.
Description
Technical Field
The invention relates to the field of ground fault detection, in particular to a method and a device for rapidly detecting multipoint ground faults of a direct current system.
Background
In a transformer substation and a converter station, power supplies of equipment such as a signal system, a relay protection device, an automatic device and the like are provided by a direct current power supply in a power supply system, the reliability of the direct current system plays a crucial role in the safe operation of the transformer substation and the converter station, once the direct current system fails, the safe and economic operation of the power system is seriously damaged, and particularly, when the direct current ground fails, the automatic protection device may be mistakenly operated or refused to operate. Because the direct current system is a complex multi-branch network, the distribution range is wide, and the probability of generating the ground fault is higher. If one point of the direct current system is not timely grounded, and when another point of the direct current system is grounded, the system fault is enlarged, and the safe and reliable operation of the power system is seriously influenced.
At present, direct current systems in a transformer substation and a converter station are both provided with direct current insulation detection devices, which can detect out poor insulation or direct current grounding branches, but if the system has two or more grounding faults, finding and judging the fault branches are very difficult.
Chinese patent publication No. CN210270042U discloses a dc defect eliminating device, which includes an ac power supply, a rectifier, a bus, a load, a voltage detecting device, and a balancing resistor, wherein the ac power supply is connected to the rectifier through a wire, three output terminals of the ac power supply are connected to three input terminals of the rectifier, an output terminal of the rectifier is connected to a bus circuit, the bus is further connected to the load and the voltage detecting device, and the bus is further connected to the balancing resistor. The load is connected between the bus M +, the bus M, and the voltage between the bus M +, the bus PE and the bus M can be changed no matter whether the load is grounded at one point or a plurality of points, and the voltage change between the buses can be reflected through the first voltage detection device, the second voltage detection device and the third voltage detection device, so that whether the loop of the load has a ground fault or not is judged, and the problems that the fault finding is difficult, the time consumption is long and the efficiency is low when the load is grounded at a plurality of points are effectively solved. The patent can detect the branch with poor insulation or direct current grounding, but if the system has two or more grounding faults, the fault branch can be very difficult to find and judge, so that the development of a method for rapidly detecting the multipoint grounding fault of the direct current system is necessary.
Disclosure of Invention
The invention aims to solve the technical problem that although the direct current fault detection device in the prior art can detect the branch with poor insulation or direct current grounding, if the system has the grounding fault condition of two points or more, the fault branch can be very difficult to search and judge.
The invention solves the technical problems through the following technical means: a method for rapidly detecting a multipoint ground fault of a dc system, the method comprising:
the method comprises the following steps: determining key nodes of N branches in a direct current system loop, and correspondingly installing a detection sensor terminal at each key node to form an NxN matrix L for describing the branches;
step two: considering system interference, setting a difference flow threshold value, constructing a difference flow description matrix D, if the difference flow of the ith branch exceeds the difference flow threshold value, setting 1 to the ith row and ith column element of the NxN dimension difference flow description matrix D, and otherwise, setting 0 to other elements of the difference flow description matrix D, wherein the ith row and ith column element of the NxN dimension difference flow description matrix D are all set to 0;
step three: multiplying the matrix L by a difference flow description matrix D to obtain a fault judgment matrix F ═ F (L × D) ═ F (F '), wherein F represents output misjudgment elimination operation, F' represents a variable of the output misjudgment elimination operation, and the output misjudgment elimination operation is as follows: if the element fijXORfji in F is 1, a ground fault occurs in a section between the ith node and the jth node on the line, and the direct-current ground fault section is reflected by a fault judgment matrix F, wherein XOR is an exclusive or operator.
The invention describes the branch and the branch fault in a matrix mode, can quickly judge and find out the multipoint ground fault of the direct current system when the direct current system has two or more ground faults, and the fault branch searching and judging process is relatively simple, thereby providing reliable direct current power supply for equipment such as a signal system, a relay protection device, an automatic device and the like, improving the working efficiency of operation and maintenance personnel and having greater economic and social benefits.
Further, the detection sensor is a current transformer.
Furthermore, the method for rapidly detecting the multipoint ground fault of the direct current system further comprises a controller, wherein the controller receives current signals of the current transformers of all key nodes.
Furthermore, the method for rapidly detecting the multipoint ground fault of the direct current system further comprises an upper computer, wherein the upper computer is connected with the controller and displays the branch current and the branch fault condition.
Further, for the nth branch, the current flowing into the nth branch from the positive bus is I1, the current flowing back into the negative bus from the nth branch is I2, and the differential current of the nth branch is I ═ I1-I2 |.
The invention also provides a device for rapidly detecting the multipoint earth fault of the direct current system, which comprises:
the branch description module is used for determining key nodes of N branches in a direct-current system loop, and correspondingly installing a detection sensor terminal at each key node to form an NxN matrix L for describing the branches;
the differential flow description module is used for setting a differential flow threshold value in consideration of system interference and constructing a differential flow description matrix D, if the differential flow of the ith branch exceeds the differential flow threshold value, setting 1 to the ith row and ith column element of the NxN dimensional differential flow description matrix D, and otherwise, setting 0 to the ith row and ith column element of the differential flow description matrix D, and setting 0 to other elements of the differential flow description matrix D;
a fault determination module, configured to multiply the matrix L by the difference flow description matrix D to obtain a fault determination matrix F (F) (L × D) (F '), where F represents an output misjudgment elimination operation, and F' represents a variable of the output misjudgment elimination operation, where the output misjudgment elimination operation is: if the element fijXORfji in F is 1, a ground fault occurs in a section between the ith node and the jth node on the line, and the direct-current ground fault section is reflected by a fault judgment matrix F, wherein XOR is an exclusive or operator.
Further, the detection sensor is a current transformer.
Furthermore, the device for rapidly detecting the multipoint ground fault of the direct current system further comprises a controller, wherein the controller receives current signals of current transformers of all key nodes.
Furthermore, the device for rapidly detecting the multipoint ground fault of the direct current system further comprises an upper computer, wherein the upper computer is connected with the controller and displays the branch current and the branch fault condition.
Further, for the nth branch, the current flowing into the nth branch from the positive bus is I1, the current flowing back into the negative bus from the nth branch is I2, and the differential current of the nth branch is I ═ I1-I2 |.
The invention has the advantages that: the invention describes the branch and the branch fault in a matrix mode, can quickly judge and find out the multipoint ground fault of the direct current system when the direct current system has two or more ground faults, and the fault branch searching and judging process is relatively simple, thereby providing reliable direct current power supply for equipment such as a signal system, a relay protection device, an automatic device and the like, improving the working efficiency of operation and maintenance personnel and having greater economic and social benefits.
Drawings
Fig. 1 is a flowchart of a method for rapidly detecting a multipoint ground fault of a dc system according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
As shown in fig. 1, a method for rapidly detecting a multipoint ground fault of a dc system includes:
step S1: determining key nodes of N branches in a direct current system loop, and correspondingly installing a detection sensor terminal at each key node to form an NxN matrix L for describing the branches; wherein, the detection sensor is a current transformer.
Step S2: considering system interference, setting a difference flow threshold value, constructing a difference flow description matrix D, if the difference flow of the ith branch exceeds the difference flow threshold value, setting 1 to the ith row and ith column element of the NxN dimension difference flow description matrix D, and otherwise, setting 0 to other elements of the difference flow description matrix D, wherein the ith row and ith column element of the NxN dimension difference flow description matrix D are all set to 0; for the nth branch, the current flowing into the nth branch from the positive bus is I1, the current flowing back into the negative bus from the nth branch is I2, and the differential current of the nth branch is I | I1-I2 |.
Step S3: multiplying the matrix L by a difference flow description matrix D to obtain a fault judgment matrix F ═ F (L × D) ═ F (F '), wherein F represents output misjudgment elimination operation, F' represents a variable of the output misjudgment elimination operation, and the output misjudgment elimination operation is as follows: if the element fijXORfji in F is 1, a ground fault occurs in a section between the ith node and the jth node on the line, and the direct-current ground fault section is reflected by a fault judgment matrix F, wherein XOR is an exclusive or operator.
In this embodiment, the method for rapidly detecting a multipoint ground fault of a dc system further includes a controller, where the controller receives current signals of current transformers of all key nodes.
In this embodiment, the method for rapidly detecting the multipoint ground fault of the dc system further includes an upper computer, which is connected to the controller and displays the branch current and the branch fault condition.
According to the technical scheme, the method for rapidly detecting the multipoint ground fault of the direct current system, which is provided by the invention, describes the branch and the branch fault in a matrix mode, can be used for rapidly judging and finding out the multipoint ground fault of the direct current system when the direct current system has the ground fault of two points or more, and the branch with the fault can be searched and judged simply, so that a reliable direct current power supply is provided for equipment such as a signal system, a relay protection device, an automatic device and the like, the working efficiency of operation and maintenance personnel is improved, and great economic and social benefits are achieved.
Example 2
Corresponding to embodiment 1 of the present invention, embodiment 2 of the present invention further provides a device for rapidly detecting a multipoint ground fault of a dc system, where the device includes:
the branch description module is used for determining key nodes of N branches in a direct-current system loop, and correspondingly installing a detection sensor terminal at each key node to form an NxN matrix L for describing the branches;
the differential flow description module is used for setting a differential flow threshold value in consideration of system interference and constructing a differential flow description matrix D, if the differential flow of the ith branch exceeds the differential flow threshold value, setting 1 to the ith row and ith column element of the NxN dimensional differential flow description matrix D, and otherwise, setting 0 to the ith row and ith column element of the differential flow description matrix D, and setting 0 to other elements of the differential flow description matrix D;
a fault determination module, configured to multiply the matrix L by the difference flow description matrix D to obtain a fault determination matrix F (F) (L × D) (F '), where F represents an output misjudgment elimination operation, and F' represents a variable of the output misjudgment elimination operation, where the output misjudgment elimination operation is: if the element fijXORfji in F is 1, a ground fault occurs in a section between the ith node and the jth node on the line, and the direct-current ground fault section is reflected by a fault judgment matrix F, wherein XOR is an exclusive or operator.
Specifically, the detection sensor is a current transformer.
Specifically, the device for rapidly detecting the multipoint ground fault of the direct current system further comprises a controller, and the controller receives current signals of current transformers of all key nodes.
Specifically, the device for rapidly detecting the multipoint ground fault of the direct current system further comprises an upper computer, wherein the upper computer is connected with the controller and displays the branch current and the branch fault condition.
Specifically, for the nth branch, the current flowing into the nth branch from the positive bus is I1, the current flowing back into the negative bus from the nth branch is I2, and the differential current of the nth branch is I ═ I1-I2 |.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. A method for rapidly detecting multipoint ground faults of a direct current system is characterized by comprising the following steps:
the method comprises the following steps: determining key nodes of N branches in a direct current system loop, and correspondingly installing a detection sensor terminal at each key node to form an NxN matrix L for describing the branches;
step two: considering system interference, setting a difference flow threshold value, constructing a difference flow description matrix D, if the difference flow of the ith branch exceeds the difference flow threshold value, setting 1 to the ith row and ith column element of the NxN dimension difference flow description matrix D, and otherwise, setting 0 to other elements of the difference flow description matrix D, wherein the ith row and ith column element of the NxN dimension difference flow description matrix D are all set to 0;
step three: multiplying the matrix L by a difference flow description matrix D to obtain a fault judgment matrix F ═ F (L × D) ═ F (F '), wherein F represents output misjudgment elimination operation, F' represents a variable of the output misjudgment elimination operation, and the output misjudgment elimination operation is as follows: if the element fijXORfji in F is 1, a ground fault occurs in a section between the ith node and the jth node on the line, and the direct-current ground fault section is reflected by a fault judgment matrix F, wherein XOR is an exclusive or operator.
2. The method for rapidly detecting the multipoint ground fault of the direct current system according to claim 1, wherein the detection sensor is a current transformer.
3. The method for rapidly detecting the multipoint ground fault of the direct current system according to claim 2, further comprising a controller, wherein the controller receives current signals of the current transformers of all the key nodes.
4. The method for rapidly detecting the multipoint ground fault of the direct current system according to claim 3, further comprising an upper computer, wherein the upper computer is connected with the controller and displays branch current and branch fault conditions.
5. The method for rapidly detecting the multipoint ground fault of the direct current system according to claim 1, wherein for the nth branch, the current flowing into the nth branch from the positive bus is I1, the current flowing back to the negative bus from the nth branch is I2, and the differential current of the nth branch is I ═ I1-I2 |.
6. An apparatus for rapidly detecting multipoint ground faults of a direct current system, the apparatus comprising:
the branch description module is used for determining key nodes of N branches in a direct-current system loop, and correspondingly installing a detection sensor terminal at each key node to form an NxN matrix L for describing the branches;
the differential flow description module is used for setting a differential flow threshold value in consideration of system interference and constructing a differential flow description matrix D, if the differential flow of the ith branch exceeds the differential flow threshold value, setting 1 to the ith row and ith column element of the NxN dimensional differential flow description matrix D, and otherwise, setting 0 to the ith row and ith column element of the differential flow description matrix D, and setting 0 to other elements of the differential flow description matrix D;
a fault determination module, configured to multiply the matrix L by the difference flow description matrix D to obtain a fault determination matrix F (F) (L × D) (F '), where F represents an output misjudgment elimination operation, and F' represents a variable of the output misjudgment elimination operation, where the output misjudgment elimination operation is: if the element fijXORfji in F is 1, a ground fault occurs in a section between the ith node and the jth node on the line, and the direct-current ground fault section is reflected by a fault judgment matrix F, wherein XOR is an exclusive or operator.
7. The apparatus for rapidly detecting multipoint ground fault of DC system according to claim 6, wherein said detecting sensor is a current transformer.
8. The apparatus of claim 7, further comprising a controller, wherein the controller receives current signals of the current transformers of all the key nodes.
9. The device for rapidly detecting the multipoint ground fault of the direct current system according to claim 8, further comprising an upper computer, wherein the upper computer is connected with the controller and displays branch current and branch fault conditions.
10. The apparatus of claim 6, wherein for the nth branch, the current flowing from the positive bus to the nth branch is I1, the current flowing from the nth branch to the negative bus is I2, and the differential current of the nth branch is I ═ I1-I2 |.
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4068275A (en) * | 1976-06-09 | 1978-01-10 | Westinghouse Electric Corporation | Ground fault protective apparatus and method |
| JP2003222650A (en) * | 2002-01-30 | 2003-08-08 | Tohoku Electric Power Co Inc | Method and system for locating wiring failure point |
| US20100008000A1 (en) * | 2008-07-14 | 2010-01-14 | General Electric Company | Ground fault protection circuit for multi-source electrical distribution system |
| CN104198884A (en) * | 2014-08-06 | 2014-12-10 | 国网山东省电力公司 | Differential principle based large-scale power grid intelligent trouble diagnosis method |
| CN106443293A (en) * | 2016-08-15 | 2017-02-22 | 国家电网公司 | Direct current ground fault online detection and alarm device |
| CN110346678A (en) * | 2019-07-17 | 2019-10-18 | 南京钢铁股份有限公司 | A kind of method of quick lookup direct current system multipoint earth faults |
| CN111766475A (en) * | 2020-07-14 | 2020-10-13 | 国网江苏省电力有限公司泗洪县供电分公司 | Disconnection fault positioning matrix algorithm |
-
2021
- 2021-01-11 CN CN202110033989.6A patent/CN112666490A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4068275A (en) * | 1976-06-09 | 1978-01-10 | Westinghouse Electric Corporation | Ground fault protective apparatus and method |
| JP2003222650A (en) * | 2002-01-30 | 2003-08-08 | Tohoku Electric Power Co Inc | Method and system for locating wiring failure point |
| US20100008000A1 (en) * | 2008-07-14 | 2010-01-14 | General Electric Company | Ground fault protection circuit for multi-source electrical distribution system |
| CN104198884A (en) * | 2014-08-06 | 2014-12-10 | 国网山东省电力公司 | Differential principle based large-scale power grid intelligent trouble diagnosis method |
| CN106443293A (en) * | 2016-08-15 | 2017-02-22 | 国家电网公司 | Direct current ground fault online detection and alarm device |
| CN110346678A (en) * | 2019-07-17 | 2019-10-18 | 南京钢铁股份有限公司 | A kind of method of quick lookup direct current system multipoint earth faults |
| CN111766475A (en) * | 2020-07-14 | 2020-10-13 | 国网江苏省电力有限公司泗洪县供电分公司 | Disconnection fault positioning matrix algorithm |
Non-Patent Citations (4)
| Title |
|---|
| QINGHUA YIN等: "Analysis and Treatment in More Than One Grounding Points on the Clamping Piece of Power Transformer", 《2020 IEEE 2ND INTERNATIONAL CONFERENCE ON POWER DATA SCIENCE (ICPDS)》 * |
| 冯卓明等: "基于差流检测的直流接地探测方法及装置研究", 《华中理工大学学报》 * |
| 刘会家等: "一种基于FTU的馈线故障定位优化算法", 《继电器》 * |
| 许磊等: "基于差流检测法的直流接地故障定位装置", 《科技传播》 * |
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