A method and device for detecting single-phase open-circuit faults in medium-voltage distribution lines

Abstract

The present invention discloses a method and device for detecting single-phase open-circuit faults in medium-voltage distribution lines. The method includes: obtaining the three-phase current values and / or three-phase voltage values of the distribution line; sorting the three-phase current values and / or three-phase voltage values according to the numerical magnitudes; when the minimum-phase current is less than the first preset proportional value of the intermediate-phase current, the maximum-phase current is less than the second preset proportional value of the intermediate-phase current, and the intermediate-phase current is greater than the preset current value, it is determined that a single-phase open-circuit fault has occurred in the distribution line, wherein the preset current value is the third preset proportional value of the rated current of the distribution line. By identifying and locating faults through the characteristics of the three-phase current or three-phase voltage collected by the distribution terminal or the device itself, the position of the single-phase open-circuit fault point in the distribution line can be accurately identified, and then the protection action of tripping or alarming can be selected without relying on the communication between the distribution terminals or devices.

Description

Technical Field

[0001] The present invention relates to the technical field of power network fault detection, and particularly to a method and device for detecting single-phase open-circuit faults in medium-voltage distribution lines. Background Art

[0002] Single-phase open-circuit faults in distribution lines are a typical fault type in the distribution network. Since the 10kV distribution network is generally a small-current grounding system, single-phase open-circuit faults do not generate a large fault current like interphase short-circuit faults, and have not received much attention. However, a single-phase open-circuit falling to the ground in the distribution line may cause single-phase grounding faults and electric shock safety accidents. With the continuous increase in the proportion of such accidents, single-phase open-circuit faults have received more and more attention. In addition, after a single-phase open-circuit in the distribution line, the three-phase voltages on the load side are abnormal, affecting the power supply to the load. Summary of the Invention

[0003] The purpose of the embodiments of the present invention is to provide a method and device for detecting single-phase open-circuit faults in medium-voltage distribution lines. By collecting the three-phase current or three-phase voltage characteristics through a distribution terminal or the device itself for fault identification and location, the position of the single-phase open-circuit fault point in the distribution line can be accurately identified, and then the protection action can be selected to trip or alarm, without relying on the communication between distribution terminals or devices.

[0004] To solve the above technical problems, the first aspect of the embodiments of the present invention provides a method for detecting single-phase open-circuit faults in medium-voltage distribution lines, including the following steps:

[0005] Obtain the three-phase current values and / or three-phase voltage values of the distribution line;

[0006] Sort the three-phase current values and / or three-phase voltage values according to the numerical magnitude;

[0007] When the minimum phase current is less than the first preset ratio value of the intermediate phase current, the maximum phase current is less than the second preset ratio value of the intermediate phase current, and the intermediate phase current is greater than the preset current value, it is determined that the distribution line has a single-phase open-circuit fault, where the preset current value is the third preset ratio value of the rated current of the distribution line.

[0008] Further, after determining that the distribution line has a single-phase open-circuit fault, it further includes:

[0009] When the phase of the minimum phase current is the same as the phase of the maximum phase voltage, it is determined as a downstream single-phase open circuit;

[0010] When the phase of the minimum phase current is the same as the phase of the minimum phase voltage, it is determined as an upstream single-phase open circuit.

[0011] Further, the numerical range of the first preset ratio value is 10% - 40%.

[0012] Further, the numerical range of the second preset ratio value is 110% - 120%.

[0013] Further, the numerical range of the third preset ratio value is 1% - 4%.

[0014] Correspondingly, a second aspect of the embodiments of the present invention provides a single-phase open-circuit fault detection device for a medium-voltage distribution line, including:

[0015] A data acquisition module, which is used to acquire the three-phase current value and / or three-phase voltage value of the distribution line;

[0016] A data sorting module, which is used to sort the three-phase current value and / or three-phase voltage value according to the numerical magnitude;

[0017] A first determination module, which is used to determine that the distribution line has a single-phase open-circuit fault when the minimum phase current is less than the first preset ratio value of the intermediate phase current, the maximum phase current is less than the second preset ratio value of the intermediate phase current, and the intermediate phase current is greater than the preset current value, wherein the preset current value is the third preset ratio value of the rated current of the distribution line.

[0018] Further, the single-phase open-circuit fault detection device for the medium-voltage distribution line further includes: a second determination module, and the second determination module includes:

[0019] A first phase discrimination unit, which is used to determine downstream single-phase open circuit when the phase of the minimum phase current is the same as the phase of the maximum phase voltage;

[0020] A second phase discrimination unit, which is used to determine upstream single-phase open circuit when the phase of the minimum phase current is the same as the phase of the minimum phase voltage.

[0021] Further, the numerical range of the first preset ratio value is 10% - 40%.

[0022] Further, the numerical range of the second preset ratio value is 110% - 120%.

[0023] Further, the numerical range of the third preset ratio value is 1% - 4%.

[0024] Correspondingly, a third aspect of the embodiments of the present invention provides an electronic device, including: at least one processor; and a memory connected to the at least one processor; wherein, the memory stores instructions executable by the one processor, and the instructions are executed by the one processor to enable the at least one processor to execute the single-phase open-circuit fault detection method for the medium-voltage distribution line as described in any one of the above.

[0025] Accordingly, a fourth aspect of the embodiments of the present invention provides a computer-readable storage medium, on which computer instructions are stored, and when the instructions are executed by a processor, the above-mentioned single-phase open-circuit fault detection method for medium-voltage distribution lines is implemented.

[0026] The above technical solutions of the embodiments of the present invention have the following beneficial technical effects:

[0027] By using the three-phase current or three-phase voltage characteristics collected by the distribution terminal or device itself for fault identification and location, the position of the single-phase open-circuit fault point in the distribution line can be accurately identified, and then the protection action tripping or warning can be selected, without relying on the communication between the distribution terminals or devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is the logic diagram of the single-phase open-circuit fault detection method for medium-voltage distribution lines provided by the embodiments of the present invention;

[0029] Figure 2 is the schematic diagram of the phase current numerical value judgment provided by the embodiments of the present invention;

[0030] Figure 3 is the schematic diagram of the phase discrimination provided by the embodiments of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with the specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0032] Please refer to Figure 1 and Figure 2 A first aspect of the embodiments of the present invention provides a single-phase open-circuit fault detection method for medium-voltage distribution lines, including the following steps:

[0033] Step S100, obtaining the three-phase current values and / or three-phase voltage values of the distribution line.

[0034] Step S200, sorting the three-phase current values and / or three-phase voltage values according to the numerical magnitudes.

[0035] Step S300, when the minimum phase current is less than the first preset ratio value of the intermediate phase current, the maximum phase current is less than the second preset ratio value of the intermediate phase current, and the intermediate phase current is greater than the preset current value, it is determined that a single-phase open-circuit fault occurs in the distribution line, where the preset current value is the third preset ratio value of the rated current of the distribution line.

[0036] Further, please refer to Figure 3, after step S300 of determining that a single-phase disconnection fault has occurred in the distribution line, it further includes:

[0037] Step S410, when the phase of the minimum phase current is the same as the phase of the maximum phase voltage, it is determined as a downstream single-phase disconnection;

[0038] Step S420, when the phase of the minimum phase current is the same as the phase of the minimum phase voltage, it is determined as an upstream single-phase disconnection.

[0039] Furthermore, the numerical range of the first preset ratio value is 10%-40%.

[0040] Furthermore, the numerical range of the second preset ratio value is 110%-120%.

[0041] Furthermore, the numerical range of the third preset ratio value is 1%-4%.

[0042] Correspondingly, a second aspect of the embodiments of the present invention provides a device for detecting single-phase disconnection faults in medium-voltage distribution lines, including:

[0043] A data acquisition module, which is used to acquire the three-phase current values and / or three-phase voltage values of the distribution line;

[0044] A data sorting module, which is used to sort the three-phase current values and / or three-phase voltage values according to the numerical magnitude;

[0045] A first determination module, which is used to determine that a single-phase disconnection fault has occurred in the distribution line when the minimum phase current is less than the first preset ratio value of the intermediate phase current, the maximum phase current is less than the second preset ratio value of the intermediate phase current, and the intermediate phase current is greater than the preset current value, where the preset current value is the third preset ratio value of the rated current of the distribution line.

[0046] Furthermore, the device for detecting single-phase disconnection faults in medium-voltage distribution lines further includes: a second determination module, and the second determination module includes:

[0047] A first phase determination unit, which is used to determine as a downstream single-phase disconnection when the phase of the minimum phase current is the same as the phase of the maximum phase voltage;

[0048] A second phase determination unit, which is used to determine as an upstream single-phase disconnection when the phase of the minimum phase current is the same as the phase of the minimum phase voltage.

[0049] Furthermore, the numerical range of the first preset ratio value is 10%-40%.

[0050] Furthermore, the numerical range of the second preset ratio value is 110%-120%.

[0051] Furthermore, the numerical range of the third preset ratio value is 1%-4%.

[0052] Correspondingly, a third aspect of the embodiments of the present invention provides an electronic device, including: at least one processor; and a memory connected to the at least one processor; wherein the memory stores instructions executable by one processor, and when the instructions are executed by one processor, the at least one processor is enabled to execute the single-phase open-circuit fault detection method for medium-voltage distribution lines as described in any of the above.

[0053] Correspondingly, a fourth aspect of the embodiments of the present invention provides a computer-readable storage medium, on which computer instructions are stored, and when the instructions are executed by a processor, the single-phase open-circuit fault detection method for medium-voltage distribution lines as described in any of the above is implemented.

[0054] The embodiments of the present invention aim to protect a single-phase open-circuit fault detection method and device for medium-voltage distribution lines. The method includes: obtaining three-phase current values and / or three-phase voltage values of a distribution line; sorting the three-phase current values and / or three-phase voltage values according to numerical magnitudes; when the minimum-phase current is less than a first preset proportional value of the intermediate-phase current, the maximum-phase current is less than a second preset proportional value of the intermediate-phase current, and the intermediate-phase current is greater than a preset current value, it is determined that a single-phase open-circuit fault occurs in the distribution line, where the preset current value is a third preset proportional value of the rated current of the distribution line. The above technical solution has the following effects:

[0055] By identifying and locating faults through the three-phase current or three-phase voltage characteristics collected by the distribution terminal or the device itself, the position of the single-phase open-circuit fault point in the distribution line can be accurately identified, and then the protection action tripping or warning can be selected without relying on the communication between the distribution terminals or devices.

[0056] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0057] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, as well as the combination of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to the processors of general-purpose computers, special-purpose computers, embedded processors, or other programmable data processing devices to generate a machine, so that the instructions executed by the processors of the computer or other programmable data processing devices generate for implementation in the processFigure 1 one process or multiple processes and / or blocks Figure 1 a device for the functions specified in one block or multiple blocks.

[0058] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory produce a manufactured article including an instruction device that implements the functions in the process Figure 1 one process or multiple processes and / or blocks Figure 1 specified in one block or multiple blocks.

[0059] These computer program instructions may also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are performed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide for implementing the functions in the process Figure 1 one process or multiple processes and / or blocks Figure 1 steps of the functions specified in one block or multiple blocks.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent replacements can still be made to the specific implementation manners of the present invention, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A single-phase open-circuit fault detection method for medium-voltage distribution lines, characterized in that, Including the following steps: Obtain the three-phase current value and / or three-phase voltage value of the distribution line; Sort the three-phase current value and / or three-phase voltage value according to the numerical magnitude; When the minimum-phase current is less than the first preset ratio value of the intermediate-phase current, the maximum-phase current is less than the second preset ratio value of the intermediate-phase current, and the intermediate-phase current is greater than the preset current value, it is determined that a single-phase disconnection fault occurs in the distribution line, where the preset current value is the third preset ratio value of the rated current of the distribution line; Wherein, the numerical range of the first preset ratio value is 10%-40%, the numerical range of the second preset ratio value is 110%-120%, and the numerical range of the third preset ratio value is 1%-4%.

2. The single-phase open-circuit fault detection method for medium-voltage distribution lines according to claim 1, wherein After determining that a single-phase disconnection fault occurs in the distribution line, it further includes: When the phase of the minimum-phase current is the same as the phase of the maximum-phase voltage, it is determined as a downstream single-phase disconnection; When the phase of the minimum-phase current is the same as the phase of the minimum-phase voltage, it is determined as an upstream single-phase disconnection.

3. A single-phase open-circuit fault detection device for medium-voltage distribution lines, characterized in that, Including: A data acquisition module, which is used to obtain the three-phase current value and / or three-phase voltage value of the distribution line; A data sorting module, which is used to sort the three-phase current value and / or three-phase voltage value according to the numerical magnitude; A first determination module, which is used to determine that a single-phase disconnection fault occurs in the distribution line when the minimum-phase current is less than the first preset ratio value of the intermediate-phase current, the maximum-phase current is less than the second preset ratio value of the intermediate-phase current, and the intermediate-phase current is greater than the preset current value, where the preset current value is the third preset ratio value of the rated current of the distribution line; Wherein, the numerical range of the first preset ratio value is 10%-40%, the numerical range of the second preset ratio value is 110%-120%, and the numerical range of the third preset ratio value is 1%-4%.

4. The single-phase open-circuit fault detection device for medium-voltage distribution lines according to claim 3, characterized in that, It further includes: A second determination module, and the second determination module includes: A first phase determination unit, which is used to determine as a downstream single-phase disconnection when the phase of the minimum-phase current is the same as the phase of the maximum-phase voltage; A second phase determination unit, which is used to determine as an upstream single-phase disconnection when the phase of the minimum-phase current is the same as the phase of the minimum-phase voltage.

5. An electronic device, characterized in that, Including: At least one processor; And a memory connected to the at least one processor; wherein, the memory stores instructions executable by the one processor, and the instructions are executed by the one processor to enable the at least one processor to execute the medium-voltage distribution line single-phase disconnection fault detection method as described in claim 1 or 2.

6. A computer-readable storage medium, characterized in that, Stored thereon are computer instructions, which when executed by a processor implement the medium-voltage distribution line single-phase disconnection fault detection method as described in claim 1 or 2.

Images