Knowledge graph-based single-phase earth fault detection processing method

Abstract

The invention provides a single-phase earth fault detection processing method based on a knowledge graph. The knowledge graph-based single-phase earth fault detection processing method comprises the following steps: under the condition that a single-phase earth fault exists in a distribution line, controlling a first switch in a plurality of switches to be switched off, and controlling the first switch to be switched on after delaying for a first time length, the first switch being a switch closest to a power supply side in the distribution line; after the first switch is switched on, under the condition that the distribution line does not have the single-phase earth fault, determining that the single-phase earth fault is an instantaneous fault; after the first switch is switched on, under the condition that the distribution line has a single-phase earth fault, determining that the single-phase earth fault is a permanent fault; a fault section in the multiple sections to be detected is determined, a second switch and a third switch are controlled to be switched off so as to isolate the fault section, and the second switch is a switch on the power side of the fault section. According to the invention, the accuracy of single-phase earth fault processing is improved.

Description

Technical Field

[0001] The present application relates to the technical field of power systems, and in particular to a single-phase grounding fault detection and processing method based on a knowledge graph. Background Art

[0002] The distribution network adopts the method of ungrounding the neutral point to improve the reliability of power supply. Single-phase grounding is the most common fault. If not handled properly, single-phase grounding can cause fire.

[0003] In the related art, when the distribution network detects that there is a single-phase grounding fault in the distribution line, it is difficult to distinguish whether the single-phase grounding fault is a transient fault or a permanent fault, resulting in low accuracy in handling the single-phase grounding fault. Summary of the invention

[0004] The present application aims to solve one of the technical problems existing in the prior art or related technology.

[0005] To this end, this application proposes a single-phase grounding fault detection and processing method based on knowledge graph.

[0006] In view of this, according to the present application, a single-phase grounding fault detection and processing method based on a knowledge graph is proposed, which is applied to a distribution line. A plurality of measuring points and a plurality of switches are arranged on the distribution line. The plurality of measuring points divide the distribution line into a plurality of sections to be tested. Each measuring point is provided with a switch. The single-phase grounding fault detection and processing method based on the knowledge graph includes: in the case where a single-phase grounding fault exists in the distribution line, controlling a first switch among a plurality of switches to be disconnected, and controlling the first switch to be reclosed after a first delay, wherein the first switch is the switch closest to the power supply side in the distribution line; after the first switch is reclosed, and in the case where there is no single-phase grounding fault in the distribution line, determining that the single-phase grounding fault is a transient fault; after the first switch is reclosed, and in the case where there is a single-phase grounding fault in the distribution line, determining that the single-phase grounding fault is a permanent fault; determining a faulty section among a plurality of sections to be tested, and controlling the second switch to be disconnected and the third switch to be disconnected to isolate the faulty section, wherein the second switch is a switch on the power supply side of the faulty section, and the third switch is a switch on the load side of the faulty section.

[0007] In this technical solution, a single-phase grounding fault detection and processing method based on knowledge graph is applied to the distribution line. Multiple measuring points are arranged on the distribution line, and each measuring point is provided with a switch. By controlling the switch action at each measuring point, the distribution line can be cut off at the measurement point.

[0008] In this technical solution, when a single-phase grounding fault is detected on the distribution line, the first switch on the distribution line is controlled to be disconnected, and the first switch is controlled to be reclosed after a first delay. The first switch is the switch closest to the power supply side in the distribution line, that is, the first switch at the outlet of the distribution line.

[0009] By disconnecting the first switch closest to the power supply side in the distribution line, the power supply can be isolated from the distribution line with a single-phase grounding fault, so that part of the distribution line on the load side of the first switch is in a power-off state. After the first switch is controlled to be disconnected, timing starts, and after the timing reaches a first time length, the first switch is controlled to be reclosed, so that part of the distribution line on the load side of the first switch is re-energized.

[0010] It should be noted that after the first switch is reclosed, the distribution line is continuously monitored for single-phase grounding faults, and the fault type of the single-phase grounding fault on the distribution line is determined accordingly.

[0011] In this technical solution, after the first switch is reclosed, it is determined again whether a single-phase grounding fault still exists in the distribution line. When it is detected that the single-phase grounding fault no longer exists in the distribution line, it is determined that the single-phase grounding fault in the distribution line has disappeared during the process of the first switch being disconnected and delayed for the first time to be reclosed, that is, the single-phase grounding fault is eliminated by the action of disconnecting and reclosing the first switch. At this time, the distribution line resumes normal operation, and it is determined that the single-phase grounding fault occurring in the distribution line is a transient fault.

[0012] In this technical solution, after the first switch is reclosed, it is determined again whether a single-phase grounding fault still exists in the distribution line. When it is detected that a single-phase grounding fault still exists in the distribution line, it is determined that after the first switch is disconnected and reclosed with a delay of the first time, the single-phase grounding fault in the distribution line still exists. It is determined that the single-phase grounding fault in the distribution line is a permanent fault, and it is necessary to locate the faulty section in the distribution line and isolate the faulty section.

[0013] In this technical solution, multiple measuring points divide the distribution line into multiple sections to be tested. When it is determined that there is a permanent single-phase grounding fault on the distribution line, the faulty section among the multiple sections to be tested is located. After the faulty section is located, the second switch on the power supply side of the faulty section is controlled to be disconnected, and the third switch on the load side of the faulty section coordinated with it is controlled to be disconnected successively and quickly, so as to quickly isolate the faulty section.

[0014] It should be noted that the knowledge graph is a knowledge graph formed based on the operation conditions of the first switch, the second switch, and the third switch on the distribution line, and combined with the current and voltage conditions on the distribution line.

[0015] In the technical solution of the present application, by setting multiple measuring points on the distribution line, and setting switches that can independently control the on and off states at each measuring point, when a fault occurs in the distribution line, by controlling the first switch closest to the power supply side to disconnect and delay reclosing, the instantaneous single-phase grounding fault can be quickly cleared, and the power supply of the distribution line can be quickly restored. When the single-phase grounding fault still exists after the first switch delays reclosing, it can be determined that the single-phase grounding fault is a permanent fault, and the faulty section in the distribution line can be quickly isolated by disconnecting the second switch on the power supply side and the third switch on the load side of the faulty section. The present application improves the accuracy of single-phase grounding fault processing, and the process of processing single-phase grounding faults does not rely on external communication, but is only implemented by using the time series of electrical quantities sensed by different measuring points after the single-phase grounding fault occurs, thereby improving reliability and economy.

[0016] In some technical solutions, optionally, controlling the second switch to be disconnected and the third switch to be disconnected includes: Controlling the second switch to be disconnected; When it is detected that the first measurement point is in a three-phase voltage loss and three-phase current loss state, the third switch is controlled to be disconnected, and the first measurement point is the measurement point corresponding to the third switch.

[0017] In this technical solution, when the single-phase grounding fault is determined to be a permanent fault, the second switch is first controlled to be disconnected. After the second switch is disconnected, when it is monitored that the first measurement point is in a three-phase voltage loss and three-phase current loss state, the third switch is controlled to be disconnected.

[0018] It should be noted that the first measurement point is a measurement point on the load side of the fault section, and the third switch is a switch arranged on the load side of the fault section.

[0019] In the technical solution of the present application, after determining that the single-phase grounding fault is a permanent fault, the third switch on the power supply side of the fault section is controlled to be disconnected, and by monitoring that the first measurement point on the power supply side of the fault section is in a three-phase voltage loss and three-phase current loss state, it can be determined that the fault section needs to be isolated at this time, so the third switch on the load side of the fault section is controlled to be disconnected. The present application only uses the change in electrical quantity sensed by the first measurement point after the permanent single-phase grounding fault occurs, controls the third switch to be disconnected to isolate the fault section, and further improves the reliability and economy.

[0020] In some technical schemes, optionally, a plurality of measuring devices are provided on the distribution line, and the plurality of measuring devices are respectively provided at a plurality of measuring points; when a single-phase grounding fault exists in the distribution line, before the first switch among the plurality of switches is controlled to be disconnected, it also includes: obtaining a zero-sequence voltage value collected by the measuring device; when the zero-sequence voltage value is greater than the voltage setting value, determining that a grounding fault exists in the distribution line; obtaining a three-phase current value collected by the measuring device; and determining whether a single-phase grounding fault exists in the distribution line according to the three-phase current value.

[0021] In this technical solution, corresponding measuring devices are set at multiple measuring points of the distribution line. The measuring devices can collect the zero-sequence voltage value at the measuring point and transmit the collected zero-sequence voltage value to the corresponding controller. The controller can compare the zero-sequence voltage with the voltage setting value. When the zero-sequence voltage value is greater than the voltage setting value, it is determined that there is a ground fault in the distribution line. When the ground fault in the distribution line is detected, it is further determined whether there is a single-phase ground fault in the distribution line.

[0022] The measuring device can also collect the three-phase current value at the measuring point and transmit the collected three-phase current value to the controller. The controller can analyze the collected three-phase current value and determine whether the ground fault is a single-phase ground fault.

[0023] In the technical solution of the present application, by setting a corresponding measuring device at a measuring point on the distribution line, the zero-sequence voltage value and the three-phase current value at the measuring point can be collected by the measuring device, and the collected zero-sequence voltage value can be used to determine whether there is a ground fault on the distribution line. In the case of a ground fault, the three-phase current value can be used to further determine whether the ground fault on the distribution line is a single-phase ground fault, thereby improving the accuracy of fault judgment and reducing hardware costs.

[0024] In some technical solutions, optionally, determining whether a single-phase grounding fault exists in a distribution line according to the three-phase current value includes: When each phase current value among the three-phase current values ​​is less than or equal to the current setting value, it is determined that a single-phase grounding fault exists in the distribution line; When any phase current value among the three-phase current values ​​is greater than the current setting value, it is determined that there is no single-phase grounding fault in the distribution line.

[0025] In the technical solution of the present application, after the three-phase current values ​​are collected, the numerical relationship between each current value in the three-phase current value and the current setting value is compared, and based on the comparison result, it can be determined whether there is a single-phase grounding fault in the distribution line, thereby improving the accuracy of the single-phase grounding fault judgment.

[0026] In some technical solutions, optionally, the measuring device includes a voltage transformer; obtaining the zero-sequence voltage value collected by the measuring device includes: obtaining the voltage measurement value collected by the voltage transformer; and determining the zero-sequence voltage value according to the voltage measurement value.

[0027] In this technical solution, the measuring device includes a voltage transformer, through which the voltage measurement value at the measuring point can be collected and transmitted to the controller. The controller can calculate the zero-sequence voltage value at the corresponding measuring point according to the voltage measurement value.

[0028] In the technical solution of the present application, a voltage transformer is provided in the measuring device, and the voltage measurement value at the measuring point can be collected through the voltage transformer, and the zero-sequence voltage value can be determined based on the voltage measurement value, and the ground fault can be judged by the zero-sequence voltage value, thereby improving the accuracy of judging the fault type and further reducing the hardware cost.

[0029] In some technical solutions, optionally, the measuring device includes a current transformer; obtaining the three-phase current value collected by the measuring device includes: obtaining the current measurement value collected by the current transformer; and determining the three-phase current value according to the current measurement value.

[0030] In this technical solution, the measuring device includes a current transformer, through which the current measurement value at the measuring point can be collected and transmitted to the controller. The controller can calculate the three-phase current value at the corresponding measuring point according to the current measurement value.

[0031] In the technical solution of the present application, a current transformer is arranged in the measuring device, and the current measurement value at the measuring point can be collected through the current transformer, and the three-phase current value can be determined based on the current measurement value, and whether the grounding fault is a single-phase grounding fault can be judged by the three-phase current value, thereby improving the accuracy of judging the fault type and further reducing the hardware cost.

[0032] In some technical schemes, optionally, determining a fault section among multiple sections to be tested includes: obtaining the change in three-phase current of each measurement point before and after the first switch is disconnected; determining the relative position relationship between each measurement point and the fault point based on the change in three-phase current; and determining the fault section based on multiple relative position relationships corresponding to multiple measurement points.

[0033] In this technical solution, before isolating the faulty section by controlling the second switch and the third switch to disconnect, it is necessary to locate the faulty section among the multiple sections to be tested. The criterion for locating the faulty section is the change in three-phase current. When there is a grounding fault in the distribution line, the three-phase current value is collected by the measuring device of each measuring point, and the three-phase current value is transmitted to the corresponding controller, and the controller can determine the change in the three-phase current according to the three-phase current value. After the controller determines the change in the three-phase current, the relative position relationship between the measuring point where the controller is located and the fault point can be determined according to the change in the three-phase current. After determining the relative position relationship between each measuring point and the fault point, the faulty sections among the multiple sections to be tested can be located according to multiple relative position relationships.

[0034] Specifically, the criterion for determining the fault section among multiple sections to be tested is the positional relationship between each measuring point and the fault point, and the criterion for the positional relationship between each measuring point and the fault point is the three-phase current change. Therefore, the three-phase current value at each measuring point is collected by a measuring device, the three-phase current change is determined by a corresponding controller, and then the positional relationship between each measuring point and the fault point is determined based on the three-phase current change.

[0035] In the technical solution of the present application, by determining the change in three-phase current at each measuring point, the relative position relationship between the corresponding measuring point and the fault point can be determined according to the change in three-phase current, and based on the relative position relationship between each measuring point and the fault point, the fault section can be located among multiple sections to be measured, thereby improving the accuracy of locating the fault section.

[0036] In some technical schemes, optionally, the relative position relationship between each measurement point and the fault point is determined based on the three-phase current change, including: obtaining the maximum change and the second largest change in the three-phase current change; when the maximum change is greater than or equal to twice the second largest change, determining that the measurement point is located on the power supply side of the fault point; when the maximum change is less than twice the second largest change, determining that the measurement point is located on the load side of the fault point.

[0037] In this technical solution, after the controller obtains the three-phase current change, it obtains the maximum change and the second largest change in the three-phase current change, and performs a numerical comparison on the maximum change and the second largest change, and determines the relative position relationship between the measurement point and the fault point based on the numerical comparison result.

[0038] Specifically, when the comparison shows that the maximum change is greater than or equal to twice the second largest change, it is determined that the measurement point is located on the power supply side of the fault point. When the comparison shows that the maximum change is less than twice the second largest change, it is determined that the measurement point is located on the load side of the fault point.

[0039] It should be noted that each measuring point of the distribution line is provided with a measuring device and a controller. After the measuring device collects the three-phase current value, it transmits the three-phase current value to the corresponding controller. The controller determines the three-phase current variation based on the three-phase current value, and extracts the largest phase current variation among the three-phase current variations, i.e., the maximum variation, and extracts the second largest phase current variation among the three-phase current variations, i.e., the second largest variation. When the maximum variation is greater than or equal to twice the second largest variation, the measuring point is located on the power supply side of the single-phase grounding fault point, and when the maximum variation is less than twice the second largest variation, the measuring point is located on the load side of the single-phase grounding fault point.

[0040] In the technical solution of the present application, the maximum change and the second largest change in the three-phase current changes at the measuring point are extracted, and by numerically comparing the maximum change with the second largest change, the relative position relationship between the measuring point and the fault point can be determined, thereby improving the accuracy of determining the relative position relationship, thereby improving the accuracy of locating the fault section among multiple sections to be measured.

[0041] In some technical solutions, optionally, determining the fault section according to a plurality of relative position relationships corresponding to a plurality of measurement points includes: When one of two adjacent measuring points is located at the power supply side of the fault point and the other measuring point is located at the load side of the fault point, the section to be measured between the two adjacent measuring points is determined to be the fault section.

[0042] In this technical solution, after determining the relative positional relationship between each measuring point and the fault point, the relative positional relationship between each two adjacent measuring points and the fault point is detected. When it is determined that one of the two adjacent measuring points is located on the power supply side of the fault point and the other measuring point is located on the load side of the fault point, it is determined that the fault section is located between the two adjacent measuring points.

[0043] In the technical solution of the present application, after obtaining the relative position relationship between each measurement point and the fault point, if there is a measurement point located on the power supply side of the fault point and a joint measurement point located on the load side of the fault point among two adjacent measurement points, it is determined that the fault section is located between the two adjacent measurement points.

[0044] In some technical solutions, optionally, the first duration ranges from 3 seconds to 8 seconds.

[0045] In the technical solution of the present application, the first time duration is the delay duration for reclosing after the first switch is disconnected. By setting the value range of the first time duration to be greater than or equal to 3 seconds, it can be ensured that the instantaneous single-phase grounding fault can be cleared within the first time duration, and by setting the value range of the first time duration to be less than or equal to 8 seconds, it can be ensured that after the instantaneous single-phase grounding fault is cleared, the power supply of the distribution line can be quickly restored.

[0046] Additional aspects and advantages of the present application will become apparent in the following description or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 A flow chart of a single-phase grounding fault detection and processing method based on a knowledge graph provided in some embodiments of the present application is shown; Figure 2 One of the power distribution line schematic diagrams provided in some embodiments of the present application is shown; Figure 3a A second schematic diagram of a power distribution line provided in some embodiments of the present application is shown; Figure 3b A third schematic diagram of a power distribution line provided in some embodiments of the present application is shown; Figure 3c A fourth schematic diagram of a power distribution line provided in some embodiments of the present application is shown; Figure 3d A fifth schematic diagram of a power distribution line provided in some embodiments of the present application is shown; Figure 4 FIG. 6 shows a sixth schematic diagram of a power distribution line provided in some embodiments of the present application.

[0048] Figure 2 The reference numerals in the figures are as follows: 200 distribution line, 201 switch, 202 section to be measured, 203 measuring device, 204 measuring point, V voltage transformer, I current transformer. DETAILED DESCRIPTION

[0049] In order to more clearly understand the above-mentioned objectives, features and advantages of the present application, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, in the absence of conflict, the present embodiment and the features in the embodiment can be combined with each other.

[0050] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited to the specific embodiments disclosed below.

[0051] Refer to the following Figures 1 to 4 A single-phase grounding fault detection and processing method based on a knowledge graph according to some embodiments of the present application is described.

[0052] According to one embodiment of the present application, Figure 1 A flow chart of a single-phase grounding fault detection and processing method based on a knowledge graph provided in some embodiments of the present application is shown. Figure 2 One of the power distribution line schematic diagrams provided in some embodiments of the present application is shown, such as Figure 1 and Figure 2 As shown, a single-phase grounding fault detection and processing method based on knowledge graph is proposed, which is applied to the distribution line. A plurality of measuring points and a plurality of switches are arranged on the distribution line. The plurality of measuring points divide the distribution line into a plurality of sections to be measured, and each measuring point is provided with a switch; In this embodiment, a single-phase grounding fault detection and processing method based on a knowledge graph is applied to a distribution line. Multiple measuring points are arranged on the distribution line, and a switch is arranged at each measuring point. By controlling the switch action at each measuring point, the distribution line can be cut off at the measuring point.

[0053] It should be noted that the knowledge graph is a knowledge graph formed based on the operation conditions of the first switch, the second switch, and the third switch on the distribution line, and combined with the current and voltage conditions on the distribution line.

[0054] Exemplarily, a controller is provided at each measuring point, and the controller can control the switch at each measuring point.

[0055] For example, the distribution line can be selected as a 10kV medium voltage distribution line, the power supply comes from the 10kV voltage side bus of the substation, and the switch cabinet is configured at the outlet of the distribution line connected to the bus in the station. The line outside the station is connected to a distribution transformer with a rating of 10kV / 380V for load power supply. In order to meet the requirements of line operation and fault isolation. Figure 2 As shown, a plurality of switches 201 are arranged on the distribution line 200, and the plurality of switches 201 are arranged on the measuring point 204 of the distribution line 200, and the plurality of switches 201 divide the distribution line into a plurality of sections 202 to be measured, and a controller for controlling the action of the switch 201 is arranged at each switch 201. A distribution line 200 is divided into a trunk line and a branch line according to the size of the power that can be distributed. Switches 201 and controllers can be arranged on both the trunk line and the branch line. In a typical configuration, a distribution line 200 trunk line is equipped with 5 sets of switches 201 and controllers, and a set of switches 201 and controllers are arranged at the outlet of the branch line. The core components of the switch 201 are the breaking element and the operating structure. The key to the breaking element is the arc extinguishing medium. The arc extinguishing medium of the switch 201 in the distribution line 200 can be selected as vacuum, SF6 gas and environmental protection gas. The operating mechanism of the switch 201 can be selected as a spring operating mechanism and a magnetic control operating mechanism.

[0056] like Figure 1As shown, the single-phase grounding fault detection and processing method based on the knowledge graph includes: Step 102, when a single-phase grounding fault occurs in the power distribution line, control a first switch among the multiple switches to be disconnected, and control the first switch to be reclosed after a first delay, wherein the first switch is the switch closest to the power supply side in the power distribution line; In this embodiment, when a single-phase grounding fault is detected on the distribution line, the first switch on the distribution line is controlled to be disconnected, and the first switch is controlled to be reclosed after a first delay. The first switch is the switch closest to the power supply side in the distribution line, that is, the first switch at the outlet of the distribution line.

[0057] By disconnecting the first switch closest to the power supply side in the distribution line, the power supply can be isolated from the distribution line with a single-phase grounding fault, so that part of the distribution line on the load side of the first switch is in a power-off state. After the first switch is controlled to be disconnected, timing starts, and after the timing reaches a first time length, the first switch is controlled to be reclosed, so that part of the distribution line on the load side of the first switch is re-energized.

[0058] Figure 3a The second schematic diagram of the power distribution line provided in some embodiments of the present application is shown. Figure 3b FIG. 3 shows a third schematic diagram of a power distribution circuit provided in some embodiments of the present application, such as Figure 3a As shown in FIG, five switches are set on the distribution line, namely PU1, PU2, PU3, PU4 and PU5. After a single-phase grounding fault is detected on the distribution line, PU1 is controlled to be disconnected. Figure 3b As shown, after PU1 is disconnected, PU1 is delayed for a first time and then closed. PU1 is the first switch.

[0059] It should be noted that after the first switch is reclosed, the distribution line is continuously monitored for single-phase grounding faults, and the fault type of the single-phase grounding fault on the distribution line is determined accordingly.

[0060] Step 104, after the first switch is reclosed and there is no single-phase grounding fault on the distribution line, determining that the single-phase grounding fault is a transient fault; In this embodiment, after the first switch is reclosed, it is determined again whether a single-phase grounding fault still exists in the distribution line, and when it is detected that the single-phase grounding fault no longer exists in the distribution line, it is determined that during the process of the first switch being disconnected and delayed for the first time period to reclose, the single-phase grounding fault in the distribution line has disappeared, that is, the single-phase grounding fault is eliminated by the action of disconnecting and reclosing the first switch. At this time, the distribution line resumes normal operation, and it is determined that the single-phase grounding fault occurring in the distribution line is a transient fault.

[0061] like Figure 3bAs shown, after PU1 is reclosed, the single-phase grounding fault on the distribution line disappears, and it is determined that the single-phase grounding fault is a transient fault. At this time, the distribution line resumes normal operation.

[0062] Step 106, after the first switch is reclosed, and in the case that a single-phase grounding fault exists in the distribution line, determining that the single-phase grounding fault is a permanent fault; In this embodiment, after the first switch is reclosed, it is determined again whether a single-phase grounding fault still exists in the distribution line. When it is detected that a single-phase grounding fault still exists in the distribution line, it is determined that after the first switch is disconnected and reclosed with a delay of the first time length, the single-phase grounding fault in the distribution line still exists, and the single-phase grounding fault in the distribution line is determined to be a permanent fault, and it is necessary to locate the faulty section in the distribution line and isolate the faulty section.

[0063] Step 108, determining the faulty section among the multiple sections to be tested, and controlling the second switch and the third switch to be disconnected to isolate the faulty section, wherein the second switch is a switch on the power supply side of the faulty section, and the third switch is a switch on the load side of the faulty section.

[0064] In this embodiment, the multiple measuring points divide the distribution line into multiple sections to be tested. When it is determined that there is a permanent single-phase grounding fault on the distribution line, the faulty section among the multiple sections to be tested is located. After the faulty section is located, the second switch on the power supply side of the faulty section is controlled to be disconnected, and the third switch on the load side of the faulty section coordinated with it is controlled to be disconnected quickly one after another, so as to quickly isolate the faulty section.

[0065] Figure 3c FIG4 shows a fourth schematic diagram of a power distribution line provided in some embodiments of the present application. Figure 3d FIG. 5 shows a fifth schematic diagram of a power distribution line provided in some embodiments of the present application, such as Figure 3c and Figure 3d As shown, when it is determined that there is a permanent fault in the distribution line and the fault section is located, the switch PU3 on the power supply side of the fault section is disconnected, and then the switch PU4 on the load side of the grounding point coordinated with it is controlled to be disconnected quickly in succession to isolate the fault section. Among them, PU3 is the second switch and PU4 is the third switch.

[0066] In the embodiment of the present application, by setting a plurality of measuring points on the distribution line, and setting a switch that can independently control the on / off state at each measuring point, when a fault occurs in the distribution line, by controlling the first switch closest to the power supply side to disconnect and delay reclosing, the instantaneous single-phase grounding fault can be quickly cleared, and the power supply of the distribution line can be quickly restored. When the single-phase grounding fault still exists after the first switch delays reclosing, it can be determined that the single-phase grounding fault is a permanent fault, and the faulty section in the distribution line can be quickly isolated by disconnecting the second switch on the power supply side and the third switch on the load side of the faulty section. The present application improves the accuracy of single-phase grounding fault processing, and the process of processing single-phase grounding fault does not rely on external communication, but is realized only by using the time series of electrical quantities sensed by different measuring points after the single-phase grounding fault occurs, thereby improving reliability and economy.

[0067] In some embodiments, optionally, controlling the second switch to be disconnected and the third switch to be disconnected includes: Controlling the second switch to be disconnected; When it is detected that the first measurement point is in a three-phase voltage loss and three-phase current loss state, the third switch is controlled to be disconnected, and the first measurement point is the measurement point corresponding to the third switch.

[0068] In this embodiment, when the single-phase grounding fault is determined to be a permanent fault, the second switch is first controlled to be disconnected. After the second switch is disconnected, when it is monitored that the first measurement point is in a three-phase voltage loss and three-phase current loss state, the third switch is controlled to be disconnected.

[0069] It should be noted that the first measurement point is a measurement point on the load side of the fault section, and the third switch is a switch arranged on the load side of the fault section.

[0070] Exemplarily, a controller is provided corresponding to each switch, that is, the controller is provided in a one-to-one correspondence with the switch, and the controller is only used to control the on / off state of the corresponding switch. The controller at the second switch determines that there is a permanent single-phase grounding fault in the fault section, and controls the second switch to disconnect. The controller at the third switch detects the three-phase loss of voltage and the three-phase loss of current through the measuring device of the measuring point, and determines that the single-phase grounding fault is a permanent fault, so the third switch is controlled to disconnect and isolate the fault section. Specifically, after the first switch is disconnected and reclosed, the controller at the third switch can obtain the corresponding voltage value and current value. After the second switch is disconnected, the three-phase loss of voltage and the three-phase loss of current are detected again at the third switch in a short time, and it is determined that there is a permanent single-phase grounding fault in the fault section, so the third switch is controlled to disconnect.

[0071] In the embodiment of the present application, after determining that the single-phase grounding fault is a permanent fault, the third switch on the power supply side of the fault section is controlled to be disconnected, and by monitoring that the first measurement point on the power supply side of the fault section is in a three-phase voltage loss and three-phase current loss state, it can be determined that the fault section needs to be isolated at this time, so the third switch on the load side of the fault section is controlled to be disconnected. The present application only uses the change in electrical quantity sensed by the first measurement point after the permanent single-phase grounding fault occurs to control the disconnection of the third switch to isolate the fault section, further improving the reliability and economy.

[0072] In some embodiments, optionally, a plurality of measuring devices are provided on the distribution line, and the plurality of measuring devices are respectively provided at a plurality of measuring points; when a single-phase grounding fault exists in the distribution line, before the first switch among the plurality of switches is controlled to be disconnected, it also includes: obtaining a zero-sequence voltage value collected by the measuring device; when the zero-sequence voltage value is greater than the voltage setting value, determining that a grounding fault exists in the distribution line; obtaining a three-phase current value collected by the measuring device; and determining whether a single-phase grounding fault exists in the distribution line according to the three-phase current value.

[0073] In this embodiment, corresponding measuring devices are provided at multiple measuring points of the distribution line, and the measuring devices can collect zero-sequence voltage values ​​at the measuring points and transmit the collected zero-sequence voltage values ​​to the corresponding controllers, and the controllers can compare the zero-sequence voltage with the voltage setting value, and determine that there is a ground fault in the distribution line when the zero-sequence voltage value is greater than the voltage setting value. When the ground fault in the distribution line is detected, it is further determined whether there is a single-phase ground fault in the distribution line.

[0074] The measuring device can also collect the three-phase current value at the measuring point and transmit the collected three-phase current value to the controller. The controller can analyze the collected three-phase current value and determine whether the ground fault is a single-phase ground fault.

[0075] like Figure 2 As shown, measuring devices 203 are respectively provided at multiple measuring points of the distribution line 200. Each measuring device 203 includes a voltage transformer V and a current transformer I. The measuring device 203 can collect current and voltage information and transmit the collected current and voltage information to the controller. The controller can determine whether a single-phase grounding fault exists in the distribution line 200 by analyzing the current and voltage information.

[0076] In the embodiment of the present application, by setting a corresponding measuring device at the measuring point on the distribution line, the zero-sequence voltage value and the three-phase current value at the measuring point can be collected by the measuring device, and the collected zero-sequence voltage value can be used to determine whether there is a ground fault on the distribution line. In the case of a ground fault, it is further determined whether the ground fault on the distribution line is a single-phase ground fault through the three-phase current value, thereby improving the accuracy of fault judgment and reducing hardware costs.

[0077] In some embodiments, optionally, determining whether a single-phase grounding fault exists in the power distribution line according to the three-phase current value includes: When each phase current value among the three-phase current values ​​is less than or equal to the current setting value, it is determined that a single-phase grounding fault exists in the distribution line; When any phase current value among the three-phase current values ​​is greater than the current setting value, it is determined that there is no single-phase grounding fault in the distribution line.

[0078] In an embodiment of the present application, after the three-phase current values ​​are collected, the numerical relationship between each current value in the three-phase current value and the current setting value is compared, and based on the comparison result, it can be determined whether there is a single-phase grounding fault in the distribution line, thereby improving the accuracy of the single-phase grounding fault judgment.

[0079] In some embodiments, optionally, the measuring device includes a voltage transformer; obtaining the zero-sequence voltage value collected by the measuring device includes: obtaining the voltage measurement value collected by the voltage transformer; and determining the zero-sequence voltage value according to the voltage measurement value.

[0080] In this embodiment, the measuring device includes a voltage transformer, through which the voltage measurement value at the measuring point can be collected and transmitted to the controller. The controller can calculate the zero-sequence voltage value at the corresponding measuring point according to the voltage measurement value.

[0081] In an embodiment of the present application, a voltage transformer is provided in the measuring device, and the voltage measurement value at the measuring point can be collected through the voltage transformer, and the zero-sequence voltage value can be determined based on the voltage measurement value, and the ground fault can be judged by the zero-sequence voltage value, thereby improving the accuracy of judging the fault type and further reducing the hardware cost.

[0082] In some embodiments, optionally, the measuring device includes a current transformer; obtaining the three-phase current value collected by the measuring device includes: obtaining the current measurement value collected by the current transformer; and determining the three-phase current value according to the current measurement value.

[0083] In this embodiment, the measuring device includes a current transformer, through which the current measurement value at the measuring point can be collected and transmitted to the controller. The controller can calculate the three-phase current value at the corresponding measuring point according to the current measurement value.

[0084] In an embodiment of the present application, a current transformer is provided in the measuring device, and the current measurement value at the measuring point can be collected through the current transformer, and the three-phase current value can be determined based on the current measurement value, and whether the grounding fault is a single-phase grounding fault can be judged by the three-phase current value, thereby improving the accuracy of judging the fault type and further reducing the hardware cost.

[0085] In some embodiments, optionally, determining a fault section among multiple sections to be tested includes: obtaining the change in three-phase current of each measurement point before and after the first switch is disconnected; determining the relative position relationship between each measurement point and the fault point based on the change in three-phase current; and determining the fault section based on multiple relative position relationships corresponding to multiple measurement points.

[0086] In this embodiment, before isolating the faulty section by controlling the second switch and the third switch to be disconnected, it is necessary to locate the faulty section among the multiple sections to be tested. The criterion for locating the faulty section is the change in three-phase current. When there is a grounding fault in the distribution line, the three-phase current value is collected by the measuring device of each measuring point, and the three-phase current value is transmitted to the corresponding controller, and the controller can determine the change in the three-phase current according to the three-phase current value. After the controller determines the change in the three-phase current, the relative position relationship between the measuring point where the controller is located and the fault point can be determined according to the change in the three-phase current. After determining the relative position relationship between each measuring point and the fault point, the faulty section among the multiple sections to be tested can be located according to multiple relative position relationships.

[0087] Specifically, the criterion for determining the fault section among multiple sections to be tested is the positional relationship between each measuring point and the fault point, and the criterion for the positional relationship between each measuring point and the fault point is the three-phase current change. Therefore, the three-phase current value at each measuring point is collected by a measuring device, the three-phase current change is determined by a corresponding controller, and then the positional relationship between each measuring point and the fault point is determined based on the three-phase current change.

[0088] In an embodiment of the present application, by determining the change in three-phase current at each measurement point, the relative position relationship between the corresponding measurement point and the fault point can be determined based on the change in three-phase current, and based on the relative position relationship between each measurement point and the fault point, the fault section can be located among multiple sections to be measured, thereby improving the accuracy of locating the fault section.

[0089] In some embodiments, optionally, the relative position relationship between each measurement point and the fault point is determined based on the three-phase current change, including: obtaining the maximum change and the second largest change in the three-phase current change; when the maximum change is greater than or equal to twice the second largest change, determining that the measurement point is located on the power supply side of the fault point; when the maximum change is less than twice the second largest change, determining that the measurement point is located on the load side of the fault point.

[0090] In this embodiment, after the controller obtains the three-phase current change, it obtains the maximum change and the second largest change among the three-phase current changes, and performs numerical comparison on the maximum change and the second largest change, and determines the relative position relationship between the measurement point and the fault point based on the numerical comparison result.

[0091] Specifically, when the comparison shows that the maximum change is greater than or equal to twice the second largest change, it is determined that the measurement point is located on the power supply side of the fault point. When the comparison shows that the maximum change is less than twice the second largest change, it is determined that the measurement point is located on the load side of the fault point.

[0092] It should be noted that each measuring point of the distribution line is provided with a measuring device and a controller. After the measuring device collects the three-phase current value, it transmits the three-phase current value to the corresponding controller. The controller determines the three-phase current variation based on the three-phase current value, and extracts the largest phase current variation among the three-phase current variations, i.e., the maximum variation, and extracts the second largest phase current variation among the three-phase current variations, i.e., the second largest variation. When the maximum variation is greater than or equal to twice the second largest variation, the measuring point is located on the power supply side of the single-phase grounding fault point, and when the maximum variation is less than twice the second largest variation, the measuring point is located on the load side of the single-phase grounding fault point.

[0093] In an embodiment of the present application, the maximum change and the second largest change in the three-phase current changes at the measuring point are extracted, and by numerically comparing the maximum change with the second largest change, the relative position relationship between the measuring point and the fault point can be determined, thereby improving the accuracy of determining the relative position relationship, thereby improving the accuracy of locating the fault section among multiple sections to be measured.

[0094] In some embodiments, optionally, determining the fault section according to a plurality of relative position relationships corresponding to a plurality of measurement points includes: When one of two adjacent measuring points is located at the power supply side of the fault point and the other measuring point is located at the load side of the fault point, the section to be measured between the two adjacent measuring points is determined to be the fault section.

[0095] In this embodiment, after the relative positional relationship between each measuring point and the fault point is determined, the relative positional relationship between each two adjacent measuring points and the fault point is detected. When it is determined that one of the two adjacent measuring points is located on the power supply side of the fault point and the other measuring point is located on the load side of the fault point, it is determined that the fault section is located between the two adjacent measuring points.

[0096] In an embodiment of the present application, after obtaining the relative position relationship between each measurement point and the fault point, if there is a measurement point located on the power supply side of the fault point and a joint measurement point located on the load side of the fault point among two adjacent measurement points, it is determined that the fault section is located between the two adjacent measurement points.

[0097] In some embodiments, optionally, the first duration ranges from 3 seconds to 8 seconds.

[0098] In the embodiment of the present application, the first time duration is the delay duration for reclosing after the first switch is disconnected. By setting the value range of the first time duration to be greater than or equal to 3 seconds, it can be ensured that the instantaneous single-phase grounding fault can be cleared within the first time duration, and by setting the value range of the first time duration to be less than or equal to 8 seconds, it can be ensured that after the instantaneous single-phase grounding fault is cleared, the power supply of the distribution line can be quickly restored.

[0099] like Figure 4 As shown, there are 5 switches on the distribution line, namely PU1, PU2, PU3, PU4 and PU5. The first action delay of the outlet protection of the distribution line is 10 seconds, and the outlet protection reclosing delay is 5 seconds. The power supply side protection delay of PU1 is 60 seconds. The power supply side protection delay of PU2 is 50 seconds, and the window position of the load side protection camera action is 59 seconds to 61 seconds. The power supply side protection delay of PU3 is 40 seconds, and the window position of the load side protection camera action is 49 seconds to 51 seconds. The power supply side protection delay of PU4 is 30 seconds, and the window position of the load side protection camera action is 39 seconds to 41 seconds. The power supply side protection delay of PU5 is 20 seconds, and the window position of the load side protection camera action is 29 seconds to 31 seconds.

[0100] It should be clarified that in the claims, specification and drawings of the present application, the term "multiple" refers to two or more than two. Unless otherwise clearly defined, the orientation or position relationship indicated by the terms "upper" and "lower" is based on the orientation or position relationship shown in the drawings, which is only for the purpose of more conveniently describing the present application and making the description process easier, rather than indicating or implying that the device or element referred to must have the specific orientation described, be constructed and operated in a specific orientation, so these descriptions cannot be understood as limitations on the present application; the terms "connect", "install", "fix" and the like should be understood in a broad sense. For example, "connection" can be a fixed connection between multiple objects, or a detachable connection between multiple objects, or an integral connection; it can be a direct connection between multiple objects, or an indirect connection between multiple objects through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood based on the specific circumstances of the above data.

[0101] In the claims, specification and drawings of the present application, the description of the terms "one embodiment", "some embodiments", "specific embodiments" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the claims, specification and drawings of the present application, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0102] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A single-phase grounding fault detection and processing method based on knowledge graph, characterized in that: Applied to a distribution line, the distribution line is provided with a plurality of measuring points and a plurality of switches, the plurality of measuring points divide the distribution line into a plurality of sections to be measured, each of the measuring points is provided with the switch, and the single-phase grounding fault detection and processing method based on the knowledge graph includes: In the case where a single-phase grounding fault exists in the power distribution line, a first switch among the multiple switches is controlled to be disconnected, and the first switch is controlled to be reclosed after a first delay, wherein the first switch is the switch closest to the power supply side in the power distribution line; After the first switch is reclosed and the distribution line does not have the single-phase grounding fault, determining that the single-phase grounding fault is a transient fault; After the first switch is reclosed, and in the case that the single-phase grounding fault exists in the power distribution line, determining that the single-phase grounding fault is a permanent fault; A faulty section among multiple sections to be tested is determined, and a second switch and a third switch are controlled to be disconnected to isolate the faulty section, wherein the second switch is the switch on the power supply side of the faulty section, and the third switch is the switch on the load side of the faulty section.

2. The single-phase grounding fault detection and processing method based on knowledge graph according to claim 1 is characterized in that: The controlling the second switch to be disconnected and the third switch to be disconnected comprises: Controlling the second switch to be disconnected; When it is detected that the first measurement point is in a three-phase voltage loss and three-phase current loss state, the third switch is controlled to be disconnected, and the first measurement point is the measurement point corresponding to the third switch.

3. The single-phase grounding fault detection and processing method based on knowledge graph according to claim 1 is characterized in that: The power distribution line is provided with a plurality of measuring devices, and the plurality of measuring devices are respectively arranged at a plurality of measuring points; In the case where a single-phase grounding fault occurs in the power distribution line, before controlling the first switch among the plurality of switches to be disconnected, the method further comprises: Obtaining the zero-sequence voltage value collected by the measuring device; When the zero-sequence voltage value is greater than the voltage setting value, it is determined that a ground fault exists in the distribution line; Obtaining three-phase current values ​​collected by the measuring device; It is determined whether the distribution line has the single-phase grounding fault according to the three-phase current values.

4. The single-phase grounding fault detection and processing method based on knowledge graph according to claim 3 is characterized in that: The determining whether the power distribution line has the single-phase grounding fault according to the three-phase current value comprises: When each phase current value of the three-phase current values ​​is less than or equal to the current setting value, it is determined that the single-phase grounding fault exists in the power distribution line; When any phase current value among the three-phase current values ​​is greater than the current setting value, it is determined that the single-phase grounding fault does not exist in the distribution line.

5. The single-phase grounding fault detection and processing method based on knowledge graph according to claim 3 is characterized in that: The measuring device comprises a voltage transformer; The obtaining of the zero-sequence voltage value collected by the measuring device comprises: Obtaining a voltage measurement value collected by the voltage transformer; The zero-sequence voltage value is determined according to the voltage measurement value.

6. The single-phase grounding fault detection and processing method based on knowledge graph according to claim 3 is characterized in that: The measuring device comprises a current transformer; The obtaining of the three-phase current values ​​collected by the measuring device comprises: Obtaining a current measurement value collected by the current transformer; The three-phase current values ​​are determined according to the current measurement values.

7. The single-phase grounding fault detection and processing method based on knowledge graph according to any one of claims 1 to 6, characterized in that: The step of determining a faulty section among a plurality of sections to be tested comprises: Obtaining a three-phase current change at each of the measurement points before and after the first switch is disconnected; Determine the relative position relationship between each of the measuring points and the fault point according to the three-phase current variation; The fault section is determined according to the plurality of relative position relationships corresponding to the plurality of measurement points.

8. The single-phase grounding fault detection and processing method based on knowledge graph according to claim 7 is characterized in that: The determining the relative position relationship between each of the measuring points and the fault point according to the three-phase current variation comprises: Obtaining the maximum change amount and the second largest change amount among the three-phase current changes; When the maximum variation is greater than or equal to twice the second largest variation, determining that the measurement point is located at the power supply side of the fault point; When the maximum variation is less than twice the second largest variation, it is determined that the measurement point is located on the load side of the fault point.

9. The single-phase grounding fault detection and processing method based on knowledge graph according to claim 7 is characterized in that: The determining the fault section according to the plurality of relative position relationships corresponding to the plurality of measurement points comprises: When one of the two adjacent measuring points is located at the power supply side of the fault point and the other measuring point is located at the load side of the fault point, the section to be measured between the two adjacent measuring points is determined to be the fault section.

10. The single-phase grounding fault detection and processing method based on knowledge graph according to any one of claims 1 to 6, characterized in that: The first duration ranges from 3 seconds to 8 seconds.

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