Single-phase ground fault detection processing device using voltage and current time series information

Abstract

The application provides a single-phase ground fault detection processing device using voltage and current time sequence information. The single-phase ground fault detection processing device using voltage and current time sequence information comprises a fault detection module, a control module, and a fault detection module. The fault detection module is used for detecting whether a power distribution line has a single-phase ground fault. The control module is used for controlling a first switch in a plurality of switches to be turned off when the power distribution line has the single-phase ground fault, and controlling the first switch to be reclosed after a first time delay. The fault detection module is used for determining that the single-phase ground fault is a transient fault when the first switch is reclosed and the power distribution line does not have the single-phase ground fault. The fault detection module is used for determining that the single-phase ground fault is a permanent fault when the first switch is reclosed and the power distribution line has the single-phase ground fault. The fault detection module is used for determining a fault section in a plurality of to-be-tested sections. The control module is used for controlling a second switch to be turned off and a third switch to be turned off.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power systems, in particular to a single-phase grounding fault detection processing device using voltage and current time series information. BACKGROUND

[0002] A power system includes power generation, power transmission, power distribution and power consumption, etc. The power is received from a power transmission network and supplied and distributed to various users through power distribution lines.

[0003] During the operation of the power distribution line, a single-phase grounding fault may occur. In the related art, the power distribution line is difficult to accurately handle the single-phase grounding fault. SUMMARY

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

[0005] To this end, the present application provides a single-phase grounding fault detection processing device using voltage and current time series information.

[0006] Therefore, the present application provides a single-phase grounding fault detection processing device using voltage and current time series information. The device is applied to a power distribution line. The power distribution line is provided with a plurality of measuring points and a plurality of switches. The plurality of measuring points divide the power distribution line into a plurality of to-be-tested sections. Each measuring point is provided with a switch. The single-phase grounding fault detection processing device using voltage and current time series information comprises: a fault detection module configured to detect whether a single-phase grounding fault exists in the power distribution line; a control module configured to, in the case that the single-phase grounding fault exists in the power distribution line, control a first switch in the plurality of switches to be opened, and control the first switch to be reclosed after a first time delay, wherein the first switch is the switch closest to the power supply side in the power distribution line; the fault detection module is configured to, after the first switch is reclosed and in the case that the single-phase grounding fault does not exist in the power distribution line, determine that the single-phase grounding fault is a transient fault; the fault detection module is configured to, after the first switch is reclosed and in the case that the single-phase grounding fault exists in the power distribution line, determine that the single-phase grounding fault is a permanent fault; the fault detection module is configured to determine a fault section in the plurality of to-be-tested sections; and the control module is configured to control a second switch and a third switch to be opened to isolate the fault section, wherein the second switch is the switch on the power supply side of the fault section, and the third switch is the switch on the load side of the fault section.

[0007] In the technical solution, the fault detection module is configured to detect whether a single-phase grounding fault exists in the power distribution line. The control module is configured to control the plurality of switches based on whether the single-phase grounding fault exists in the power distribution line.

[0008] When detecting that there is a single-phase ground fault on the power distribution line, the first switch on the power distribution line is controlled to be opened, and the first switch is controlled to reclose after a first time length. The first switch is the switch closest to the power supply side in the power distribution line, that is, the first switch at the outlet of the power distribution line.

[0009] By opening the first switch closest to the power supply side in the power distribution line, the power supply can be isolated from the power distribution line with a single-phase ground fault, so that the part of the power distribution line on the load side of the first switch is in a power-off state. After the first switch is controlled to be opened, timing is started, and after the timing reaches the first time length, the first switch is controlled to reclose, so that the part of the power distribution line on the load side of the first switch is re-powered.

[0010] It should be noted that after the first switch is reclosed, it is continued to monitor whether there is a single-phase ground fault on the power distribution line, and the fault type of the single-phase ground fault on the power distribution line is judged accordingly.

[0011] After the first switch is reclosed, it is judged again whether there is still a single-phase ground fault on the power distribution line, and when it is detected that there is no longer a single-phase ground fault on the power distribution line, it is determined that the single-phase ground fault on the power distribution line has disappeared in the process of opening and reclosing the first switch for the first time length, that is, the single-phase ground fault is eliminated by the action of opening and reclosing the first switch. At this time, the power distribution line returns to normal operation, and it is determined that the single-phase ground fault occurring on the power distribution line is a transient fault.

[0012] After the first switch is reclosed, it is judged again whether there is still a single-phase ground fault on the power distribution line, and when it is detected that there is still a single-phase ground fault on the power distribution line, it is determined that the single-phase ground fault on the power distribution line still exists after the first switch is opened and reclosed for the first time length, and it is determined that the single-phase ground fault on the power distribution line is a permanent fault, and the fault section on the power distribution line needs to be located and isolated.

[0013] The plurality of measurement points divide the power distribution line into a plurality of to-be-measured sections. When it is determined that there is a permanent single-phase ground fault on the power distribution line, the fault section in the plurality of to-be-measured sections is located. After the fault section is located, the second switch on the power supply side of the fault section is controlled to be opened, and the third switch on the load side of the fault section cooperating with the second switch is controlled to be opened in succession, so as to quickly isolate the fault section.

[0014] In the technical solution of the application, a plurality of measuring points are arranged on the power distribution line, and a switch capable of being controlled to be on or off is arranged at each measuring point. When a fault occurs in the power distribution line, the first switch closest to the power supply side is controlled to be off and time-delay reclosing is performed, so that a transient single-phase ground fault can be quickly cleared and the power supply of the power distribution line can be quickly restored. When the single-phase ground fault still exists after time-delay reclosing of the first switch, it is determined that the single-phase ground fault is a permanent fault, and the second switch on the power supply side and the third switch on the load side of the fault section are controlled to be off, so that the fault section in the power distribution line can be quickly isolated. The application improves the accuracy of single-phase ground fault processing, and the process of processing the single-phase ground fault does not depend on external communication, but only uses the electrical quantity time sequence sensed by different measuring points after the occurrence of the single-phase ground fault, thereby improving the reliability and economy.

[0015] In some technical solutions, the control module includes a first sub-control module and a second sub-control module, the first sub-control module corresponds to the second switch, and the second sub-control module corresponds to the third switch.

[0016] The process of the control module controlling the second switch to be off and the third switch to be off includes:

[0017] The first sub-control module is configured to control the second switch to be off.

[0018] The second sub-control module is configured to control the third switch to be off when the first measuring point is in a three-phase voltage loss and three-phase current loss state, the first measuring point being the measuring point corresponding to the third switch.

[0019] In this technical solution, the control module includes a first sub-control module and a second sub-control module for controlling the actions of different switches, the first sub-control module is configured to control the on-off state of the second switch, and the second sub-control module is configured to control the on-off state of the third switch.

[0020] It should be noted that the control module includes a plurality of sub-control modules, the plurality of sub-control modules correspond to the plurality of switches one by one, and the plurality of sub-control modules are configured to control the on-off states of the plurality of switches, respectively.

[0021] In this technical solution, when it is determined that the single-phase ground fault is a permanent fault, the second switch is first controlled to be off. After the second switch is off, the third switch is controlled to be off when it is monitored that the first measuring point is in a three-phase voltage loss and three-phase current loss state.

[0022] It should be noted that the first measuring point is a measuring 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.

[0023] In the technical solution, after determining that the single-phase grounding fault is a permanent fault, the third switch on the power side of the fault section is controlled to be turned off, and the first measuring point on the power side of the fault section is monitored to be in a three-phase voltage loss and three-phase current loss state, so that it is determined that the fault section needs to be isolated at this time, and the third switch on the load side of the fault section is controlled to be turned off. The third switch is controlled to be turned off to isolate the fault section by using only the change of the electrical quantity sensed by the first measuring point after the occurrence of the permanent single-phase grounding fault, thereby further improving the reliability and economy.

[0024] In some technical solutions, a plurality of measuring devices are arranged on the power distribution line, and the plurality of measuring devices are arranged at the plurality of measuring points, respectively.

[0025] The single-phase grounding fault detection processing device using voltage and current time series information further comprises:

[0026] The first sampling module is configured to acquire the zero sequence voltage value collected by the measuring device.

[0027] The fault detection module is configured to determine that the power distribution line has a grounding fault when the zero sequence voltage value is greater than the voltage setting value.

[0028] The first sampling module is configured to acquire the three-phase current value collected by the measuring device.

[0029] The fault detection module is configured to determine whether the power distribution line has a single-phase grounding fault according to the three-phase current value.

[0030] In the technical solution, the first sampling module is in communication connection with the measuring device, and the measuring device transmits the sampled voltage and current information to the fault detection module or the control module through the first sampling module, so that the fault detection module and the control module perform corresponding actions based on the voltage and current information.

[0031] In the technical solution, the corresponding measuring device is arranged on each measuring point of the power distribution line, the measuring device can collect the zero sequence voltage value at the measuring point and transmit the collected zero sequence voltage value to the corresponding controller, and the controller can compare the zero sequence voltage with the voltage setting value and determine that the power distribution line has a grounding fault when the zero sequence voltage value is greater than the voltage setting value. After detecting that the power distribution line has a grounding fault, it is further determined whether the power distribution line has a single-phase grounding fault.

[0032] 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, and the controller can analyze the collected three-phase current value and determine whether the grounding fault is a single-phase grounding fault.

[0033] In the technical scheme of the present application, the corresponding measuring device is arranged at the measuring point on the power distribution line, the zero sequence voltage value and the three-phase current value at the measuring point can be collected by the measuring device, whether there is a grounding fault on the power distribution line can be determined by the collected zero sequence voltage value, and whether the grounding fault on the power distribution line is a single-phase grounding fault can be further determined by the three-phase current value in the case of the grounding fault, so that the accuracy of fault determination is improved, and the hardware cost is also reduced.

[0034] In some technical schemes, the fault detection module is configured to determine that the power distribution line has a single-phase grounding fault in the case that each of the three-phase current values is less than or equal to the current setting value.

[0035] The fault detection module is configured to determine that the power distribution line does not have a single-phase grounding fault in the case that any of the three-phase current values is greater than the current setting value.

[0036] In the technical scheme of the present application, after the three-phase current values are collected, the numerical relationship between each of the three-phase current values and the current setting value is compared, and whether the power distribution line has a single-phase grounding fault can be determined based on the comparison result, so that the accuracy of single-phase grounding fault determination is improved.

[0037] In some technical schemes, the measuring device comprises a voltage transformer.

[0038] The first sampling module is configured to obtain the voltage measurement value collected by the voltage transformer.

[0039] The fault detection module comprises:

[0040] The first processing module is configured to determine the zero sequence voltage value according to the voltage measurement value.

[0041] In the technical scheme, the first processing module is included in the fault detection module, the first processing module can receive the voltage measurement value from the first sampling module, and the zero sequence voltage value can be calculated based on the voltage measurement value.

[0042] In the technical scheme, the measuring device comprises a voltage transformer, the voltage measurement value at the measuring point can be collected by the voltage transformer, and the voltage measurement value is transmitted to the controller. The controller can calculate the corresponding zero sequence voltage value at the measuring point according to the voltage measurement value.

[0043] In the technical scheme of the present application, the voltage transformer is arranged in the measuring device, the voltage measurement value at the measuring point can be collected by the voltage transformer, the zero sequence voltage value can be determined according to the voltage measurement value, and the grounding fault can be determined by the zero sequence voltage value, so that the accuracy of fault type determination is improved, and the hardware cost is further reduced.

[0044] In some embodiments, the measurement device comprises a current transformer.

[0045] The first sampling module is configured to acquire the current measurement value collected by the current transformer.

[0046] The fault detection module comprises:

[0047] The second processing module is configured to determine the three-phase current value based on the current measurement value.

[0048] In this embodiment, the second processing module is included in the fault detection module, and the second processing module can receive the current measurement value from the second sampling module and calculate the three-phase current value based on the current measurement value.

[0049] In this embodiment, the measurement device comprises a current transformer, and the current transformer can collect the current measurement value at the measurement point and transmit the current measurement value to the controller. The controller can calculate the three-phase current value at the corresponding measurement point based on the current measurement value.

[0050] In the present application, a current transformer is provided in the measurement device, and the current transformer can collect the current measurement value at the measurement point. The three-phase current value can be determined based on the current measurement value, and the single-phase grounding fault can be determined based on the three-phase current value. This improves the accuracy of fault type determination and further reduces the hardware cost.

[0051] In some embodiments, the single-phase grounding fault detection processing device using voltage and current time series information further comprises:

[0052] The second sampling module is configured to acquire the three-phase current variation of each measurement point before and after the first switch is opened.

[0053] The fault detection module further comprises:

[0054] The third processing module is configured to determine the relative position relationship between each measurement point and the fault point based on the three-phase current variation.

[0055] The third processing module is configured to determine the fault section based on the plurality of relative position relationships corresponding to the plurality of measurement points.

[0056] In this embodiment, the second sampling module is in communication connection with the measurement device, and the second sampling module can acquire the three-phase current variation of each measurement point before and after the first switch is opened through the measurement device. The third processing module is configured to determine the relative position relationship between each measurement point and the fault point based on the three-phase current variation collected by the second sampling module, and to locate the fault section in the plurality of to-be-tested sections based on the determined relative position relationship.

[0057] In the technical solution, the fault section needs to be located among the multiple to-be-tested sections before the second switch and the third switch are controlled to disconnect the isolation of the fault section. The criterion for locating the fault section is the three-phase current variation. When there is a ground fault in the power distribution line, the three-phase current values are collected by the measuring device of each measuring point and transmitted to the corresponding controller, and the controller can determine the three-phase current variation according to the three-phase current values. After the controller determines the three-phase current variation, the relative positional relationship between the measuring point where the controller is located and the fault point can be determined according to the three-phase current variation. After the relative positional relationship between each measuring point and the fault point is determined, the fault section among the multiple to-be-tested sections can be located according to the multiple relative positional relationships.

[0058] Specifically, the criterion for determining the fault section among the multiple to-be-tested sections 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 variation. Therefore, the three-phase current values at each measuring point are collected by the measuring device, the three-phase current variation is determined by the corresponding controller, and the positional relationship between each measuring point and the fault point is determined based on the three-phase current variation.

[0059] In the technical solution of the present application, the three-phase current variation at each measuring point is determined, the relative positional relationship between the corresponding measuring point and the fault point can be determined according to the three-phase current variation, and the fault section among the multiple to-be-tested sections is located based on the relative positional relationship between each measuring point and the fault point, thereby improving the accuracy of locating the fault section.

[0060] In some technical solutions, the third processing module is further configured to obtain the maximum variation and the second largest variation in the three-phase current variation.

[0061] The third processing module is further configured to determine that the measuring point is located on the power supply side of the fault point when the maximum variation is greater than or equal to twice the second largest variation.

[0062] The third processing module is further configured to determine that the measuring point is located on the load side of the fault point when the maximum variation is less than twice the second largest variation.

[0063] In the technical solution, after the controller obtains the three-phase current variation, the maximum variation and the second largest variation in the three-phase current variation are obtained, and the maximum variation and the second largest variation are compared in value, and the relative positional relationship between the measuring point and the fault point is determined based on the comparison result.

[0064] Specifically, in a case where the maximum change amount is greater than or equal to twice the second maximum change amount, it is determined that the measurement point is located on the power supply side of the fault point, and in a case where the maximum change amount is less than twice the second maximum change amount, it is determined that the measurement point is located on the load side of the fault point.

[0065] It should be noted that the measurement device and the controller are arranged at each measurement point of the power distribution line. After the three-phase current values are collected by the measurement device, the three-phase current values are transmitted to the corresponding controller. The controller determines the three-phase current change amounts based on the three-phase current values, extracts the maximum phase current change amount, i.e., the maximum change amount, from the three-phase current change amounts, and extracts the second maximum phase current change amount, i.e., the second maximum change amount, from the three-phase current change amounts. In a case where the maximum change amount is greater than or equal to twice the second maximum change amount, the measurement point is located on the power supply side of the single-phase grounding fault point, and in a case where the maximum change amount is less than twice the second maximum change amount, the measurement point is located on the load side of the single-phase grounding fault point.

[0066] In the technical solution of the present application, the maximum change amount and the second maximum change amount of the three-phase current change amounts at the measurement point are extracted, and the relative positional relationship between the measurement point and the fault point is determined by comparing the maximum change amount with the second maximum change amount, thereby improving the accuracy of determining the relative positional relationship and the accuracy of locating the fault section in the plurality of to-be-measured sections.

[0067] In some technical solutions, optionally, the third processing module is further configured to determine, in a case where one of the two adjacent measurement points is located on the power supply side of the fault point and the other measurement point is located on the load side of the fault point, that the to-be-measured section between the two adjacent measurement points is the fault section.

[0068] In the technical solution, after the relative positional relationship between each measurement point and the fault point is determined, the relative positional relationship between each adjacent two measurement points and the fault point is detected. When one of the two adjacent measurement points is located on the power supply side of the fault point and the other measurement point is located on the load side of the fault point, it is determined that the fault section is located between the two adjacent measurement points.

[0069] In the technical solution of the present application, after the relative positional relationship between each measurement point and the fault point is obtained, when one of the two adjacent measurement points is located on the power supply side of the fault point and the other measurement point is located on the load side of the fault point, it is determined that the fault section is located between the two adjacent measurement points.

[0070] In some technical solutions, optionally, the first time length is 3 seconds to 8 seconds.

[0071] In the technical solution of the present application, the first time length is a delay time length after the first switch is turned off, by setting the value range of the first time length to be greater than or equal to 3 seconds, it can be ensured that the instantaneous single-phase ground fault can be cleared within the first time length, and by setting the value range of the first time length to be less than or equal to 8 seconds, it can be ensured that after the instantaneous single-phase ground fault is cleared, the power supply of the power distribution line is quickly restored.

[0072] Additional aspects and advantages of the present application will become apparent from the following description with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0073] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood by considering the following detailed description, including the accompanying drawings, in which:

[0074] Figure 1 A structural block diagram of a single-phase ground fault detection processing device using voltage and current time sequence information provided in some embodiments of the present application is shown;

[0075] Figure 2 One of the power distribution line schematic diagrams provided in some embodiments of the present application is shown;

[0076] Figure 3a The second power distribution line schematic diagram provided in some embodiments of the present application is shown;

[0077] Figure 3b The third power distribution line schematic diagram provided in some embodiments of the present application is shown;

[0078] Figure 3c The fourth power distribution line schematic diagram provided in some embodiments of the present application is shown;

[0079] Figure 3d The fifth power distribution line schematic diagram provided in some embodiments of the present application is shown;

[0080] Figure 4 The sixth power distribution line schematic diagram provided in some embodiments of the present application is shown.

[0081] Figure 2 The reference signs in the drawings are as follows:

[0082] 200 power distribution line, 201 switch, 202 section to be measured, 203 measurement device. DETAILED DESCRIPTION

[0083] In order to enable a clearer understanding of the above-mentioned purposes, features and advantages of the present application, the present application will be further described in detail below in combination with the drawings and specific embodiments. It should be noted that the features in the embodiments and the embodiments can be combined with each other without conflict.

[0084] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without the specific details set forth in this description.

[0085] The following description refers to the accompanying drawings. Figures 1 to 4 A single-phase ground fault detection processing device using voltage and current time series information according to some embodiments of the present application is described.

[0086] According to one embodiment of the present application, Figure 1 A structural block diagram of a single-phase ground fault detection processing device using voltage and current time series information according to some embodiments of the present application is shown, Figure 2 A schematic diagram of one of the distribution lines according to some embodiments of the present application is shown, as Figure 1 and Figure 2 A single-phase ground fault detection processing device using voltage and current time series information is proposed, which is applied to a distribution line, and the distribution line is provided with multiple measuring points and multiple switches. The multiple measuring points divide the distribution line into multiple to-be-measured sections, and each measuring point is provided with a switch.

[0087] In this embodiment, the single-phase ground fault processing method is applied to a distribution line, and the distribution line is provided with multiple measuring points, and each measuring point is provided with a switch. By controlling the action of the switch at each measuring point, the distribution line can be cut off at the measuring point position.

[0088] Exemplarily, a controller is arranged at each measuring point, and the controller can control the switch at each measuring point.

[0089] Exemplarily, the distribution line can be a 10kV medium-voltage distribution line, and the power source is from a 10kV voltage side bus of a transformer substation. A switch cabinet is configured at the outlet of the distribution line connected with the bus in the substation. A distribution transformer is connected to the line outside the substation, and the distribution transformer is of 10kV / 380V grade, which is used for load power supply. In order to meet the requirements of line operation and fault isolation, as Figure 2As shown, multiple switches 201 are installed on the power distribution line 200. These switches 201 are located at measurement points on the power distribution line 200, and divide the power distribution line into multiple test sections 202. Each switch 201 is equipped with a controller to control its operation. A power distribution line 200 is divided into main lines and branch lines based on the power it can distribute. Switches 201 and controllers can be configured on both main lines and branch lines. In a typical configuration, a main line of a power distribution line 200 is equipped with 5 sets of switches 201 and controllers, and a branch line outlet is equipped with 1 set of switches 201 and controllers. The core components of the switch 201 are the breaking element and the operating mechanism. The key to the breaking element is the arc-extinguishing medium. The arc-extinguishing medium of the switch 201 in the power distribution line 200 can be selected from vacuum, SF6 gas, and environmentally friendly gas. The switch operating mechanism can be selected from spring operating mechanism and magnetic control operating mechanism.

[0090] like Figure 1 As shown, the single-phase ground fault detection and processing device 100 utilizing voltage and current time series information includes:

[0091] Fault detection module 102 is used to detect whether there is a single-phase grounding fault in the power distribution line;

[0092] The control module 104 is used to control the first switch among multiple switches to open when there is a single-phase ground fault in the power distribution line, and to control the first switch to reclose after a first time delay. The first switch is the switch in the power distribution line that is closest to the power source side.

[0093] The fault detection module 102 is used to determine that the single-phase grounding fault is a transient fault after the first switch is reclosed and there is no single-phase grounding fault in the power distribution line.

[0094] The fault detection module 102 is used to determine that the single-phase grounding fault is a permanent fault when the first switch is reclosed and there is a single-phase grounding fault in the power distribution line.

[0095] Fault detection module 102 is used to identify faulty sections among multiple test sections;

[0096] The control module 104 is used to control the second switch and the third switch to disconnect in order to isolate the faulty section. The second switch is the power supply side switch of the faulty section, and the third switch is the load side switch of the faulty section.

[0097] In this embodiment, the fault detection module 102 is used to detect whether a single-phase ground fault exists in the power distribution line. The control module 104 is used to control multiple switches based on whether a single-phase ground fault exists in the power distribution line.

[0098] When detecting that there is a single-phase ground fault on the power distribution line, a first switch on the power distribution line is controlled to be opened, and the first switch is controlled to reclose after a first time length. The first switch is the switch closest to the power supply side in the power distribution line, that is, the first switch at the outlet of the power distribution line.

[0099] By opening the first switch closest to the power supply side in the power distribution line, the power supply can be isolated from the power distribution line with a single-phase ground fault, so that the part of the power distribution line on the load side of the first switch is in a power-off state. After the first switch is controlled to be opened, timing is started, and after the timing reaches the first time length, the first switch is controlled to reclose, so that the part of the power distribution line on the load side of the first switch is re-powered.

[0100] Figure 3a Fig. 2 shows a schematic diagram of a power distribution line provided in some embodiments of the present application, Figure 3b Fig. 3 shows a schematic diagram of a power distribution line provided in some embodiments of the present application, as Figure 3a As shown in Fig. 3, five switches PU1, PU2, PU3, PU4 and PU5 are arranged on the power distribution line, and PU1 is controlled to be opened after detecting that a single-phase ground fault occurs on the power distribution line. As Figure 3b shown, PU1 recloses after being opened for a first time length. PU1 is the first switch.

[0101] It should be noted that after the first switch recloses, it is still necessary to monitor whether there is a single-phase ground fault on the power distribution line, and to determine the fault type of the single-phase ground fault on the power distribution line according to the monitoring result.

[0102] After the first switch recloses, it is determined again whether there is still a single-phase ground fault on the power distribution line. When it is detected that there is no longer a single-phase ground fault on the power distribution line, it is determined that the single-phase ground fault on the power distribution line has disappeared during the process of opening and reclosing the first switch for the first time length, that is, the single-phase ground fault is eliminated by the action of opening and reclosing the first switch. At this time, the power distribution line returns to normal operation, and it is determined that the single-phase ground fault occurring on the power distribution line is a transient fault.

[0103] After the first switch recloses, it is determined again whether there is still a single-phase ground fault on the power distribution line. When it is detected that there is still a single-phase ground fault on the power distribution line, it is determined that the single-phase ground fault on the power distribution line still exists after the first switch is opened and reclosed for the first time length, and it is determined that the single-phase ground fault on the power distribution line is a permanent fault. It is necessary to locate the fault section on the power distribution line and isolate the fault section.

[0104] Multiple measurement points divide the power distribution line into multiple test sections. If a permanent single-phase ground fault is determined to exist on the power distribution line, the faulty section among the multiple test sections is located. After locating the faulty section, the second switch on the power supply side of the faulty section is opened, and the third switch on the load side of the corresponding faulty section is opened in quick succession to quickly isolate the faulty section.

[0105] Figure 3c The fourth illustration shows a power distribution line diagram provided in some embodiments of this application. Figure 3d The fifth illustration shows a schematic diagram of a power distribution line provided in some embodiments of this application, such as... Figure 3c and Figure 3d As shown, when a permanent fault is confirmed in the power distribution line and the faulty section is located, the switch PU3 on the power supply side of the faulty section is disconnected, and then the switch PU4 on the load side of the grounding point, which is paired with it, is simultaneously disconnected to isolate the faulty section. PU3 is the second switch, and PU4 is the third switch.

[0106] In this embodiment, by setting multiple measurement points on the power distribution line and installing a switch at each measurement point that can be individually controlled for on / off states, when a fault occurs in the power distribution line, the transient single-phase ground fault can be quickly cleared and the power supply to the power distribution line can be quickly restored by controlling the first switch closest to the power supply side to open and then reclosing it after a delay. If the single-phase ground fault still exists after the first switch reclosing after a delay, it can be determined that the single-phase ground fault is a permanent fault. By opening the second switch on the power supply side and the third switch on the load side of the faulty section, the faulty section in the power distribution line can be quickly isolated. This application improves the accuracy of single-phase ground fault handling, and the process of handling single-phase ground faults does not rely on external communication, but only utilizes the time series of electrical quantities sensed by different measurement points after the occurrence of a single-phase ground fault, thus improving reliability and economy.

[0107] In some embodiments, the control module 104 may optionally include a first sub-control module 104 and a second sub-control module 104, wherein the first sub-control module 104 corresponds to a second switch and the second sub-control module 104 corresponds to a third switch;

[0108] The process of the second switch and the third switch of the control module 104 being turned off includes:

[0109] The first sub-control module 104 is used to control the second switch to open;

[0110] The second sub-control module 104 is used to control the third switch to open when the first measurement point is in a state of three-phase undervoltage and three-phase undercurrent. The first measurement point is the measurement point corresponding to the third switch.

[0111] In this embodiment, the control module 104 includes a first sub-control module 104 and a second sub-control module 104 for controlling the actions of different switches. The first sub-control module 104 is used to control the on / off state of the second switch, and the second sub-control module 104 is used to control the on / off state of the third switch.

[0112] It should be noted that the control module 104 includes multiple sub-control modules 104, each of which corresponds to a multiple switch. The multiple sub-control modules 104 are used to control the on / off state of the multiple switches respectively.

[0113] In this embodiment, if the single-phase ground fault is determined to be a permanent fault, the second switch is first controlled to open. After the second switch is opened, if the first measuring point is detected to be in a state of three-phase voltage and three-phase current loss, the third switch is controlled to open.

[0114] It should be noted that the first measurement point is the measurement point on the load side of the fault section, and the third switch is the switch set on the load side of the fault section.

[0115] For example, each switch is associated with a controller, meaning there is a one-to-one correspondence between the controller and the switch. The controller is only used to control the on / off state of the corresponding switch. If the controller at the second switch determines that a permanent single-phase ground fault exists in the faulty section, it will control the second switch to open. If the controller at the third switch detects three-phase voltage and current loss through the measuring devices at the measuring points, it will determine that the single-phase ground fault is permanent and will therefore control the third switch to open, isolating the faulty section. Specifically, after the first switch is opened and reclosed, the controller at the third switch can obtain the corresponding voltage and current values. If, after the second switch is opened, the third switch detects three-phase voltage and current loss again within a short period, it will determine that a permanent single-phase ground fault exists in the faulty section and will therefore control the third switch to open.

[0116] In this embodiment, after determining that the single-phase ground fault is a permanent fault, the third switch on the power supply side of the faulty section is opened. By monitoring the first measuring point on the power supply side of the faulty section to determine if it is in a state of three-phase voltage and three-phase current loss, it can be determined that the faulty section needs to be isolated. Therefore, the third switch on the load side of the faulty section is opened. This application utilizes only the electrical quantity changes sensed by the first measuring point after a permanent single-phase ground fault occurs to control the third switch to open and isolate the faulty section, further improving reliability and economy.

[0117] In some embodiments, optionally, a plurality of measuring devices are provided on the power distribution line, and the plurality of measuring devices are respectively provided at a plurality of measuring points;

[0118] The single-phase ground fault detection and processing device 100, which utilizes voltage and current time series information, further includes:

[0119] The first sampling module is used to acquire the zero-sequence voltage value collected by the measuring device;

[0120] The fault detection module 102 is used to determine that there is a grounding fault in the power distribution line when the zero-sequence voltage value is greater than the voltage setting value;

[0121] The first sampling module is used to acquire the three-phase current values ​​collected by the measuring device;

[0122] The fault detection module 102 is used to determine whether a single-phase grounding fault exists in the power distribution line based on the three-phase current value.

[0123] In this embodiment, the first sampling module is communicatively connected to the measuring device. The measuring device transmits the sampled voltage and current information to the fault detection module 102 or the control module 104 through the first sampling module, so that the fault detection module 102 and the control module 104 can perform corresponding actions based on the voltage and current information.

[0124] In this embodiment, corresponding measuring devices are installed at multiple measuring points on the power distribution line. These devices can collect the zero-sequence voltage value at each measuring point and transmit it to a corresponding controller. The controller compares the zero-sequence voltage with a voltage setting value. If the zero-sequence voltage value is greater than the voltage setting value, a grounding fault is determined in the power distribution line. Upon detecting a grounding fault, the system further determines whether a single-phase grounding fault exists.

[0125] The measuring device can also collect the three-phase current values ​​at the measuring point and transmit the collected three-phase current values ​​to the controller. The controller can analyze the collected three-phase current values ​​and determine whether the grounding fault is a single-phase grounding fault.

[0126] like Figure 2 As shown, a measuring device 203 is installed at multiple measuring points of the power distribution line 200. The measuring device 203 can collect current and voltage information and transmit the collected current and voltage information to the controller. The controller analyzes the current and voltage information and can determine that there is a single-phase grounding fault in the power distribution line 200.

[0127] In this embodiment, by setting corresponding measuring devices at the measurement points on the power distribution line, the measuring devices can collect the zero-sequence voltage value and three-phase current value at the measurement points. The collected zero-sequence voltage value can be used to determine whether there is a grounding fault on the power distribution line. If there is a grounding fault, the three-phase current value can be used to further determine whether the grounding fault on the power distribution line is a single-phase grounding fault, which improves the accuracy of fault judgment and also reduces hardware costs.

[0128] In some embodiments, the fault detection module 102 is optionally configured to determine that a single-phase grounding fault exists in the power distribution line when the current value of each phase in the three-phase current values ​​is less than or equal to the current setting value.

[0129] The fault detection module 102 is used to determine that there is no single-phase grounding fault in the power distribution line when any phase current value in the three-phase current values ​​is greater than the current setting value.

[0130] In this embodiment of the application, after the three-phase current values ​​are collected, the numerical relationship between each current value and the current setting value in the three-phase current values ​​is compared, and based on the comparison results, it can be determined whether there is a single-phase grounding fault in the power distribution line, thereby improving the accuracy of the single-phase grounding fault judgment.

[0131] In some embodiments, the measuring device may optionally include a voltage transformer;

[0132] The first sampling module is used to acquire the voltage measurement value collected by the voltage transformer;

[0133] Fault detection module 102 includes:

[0134] The first processing module is used to determine the zero-sequence voltage value based on the voltage measurement value.

[0135] In this embodiment, the fault detection module 102 includes a first processing module, which can receive voltage measurement values ​​from the first sampling module and calculate the zero-sequence voltage value based on the voltage measurement values.

[0136] In this embodiment, the measuring device includes a voltage transformer, which can collect voltage measurements at the measuring point and transmit these measurements to the controller. The controller can then calculate the zero-sequence voltage value at the corresponding measuring point based on the voltage measurements.

[0137] In this embodiment of the application, a voltage transformer is set in the measurement device. The voltage transformer can collect the voltage measurement value at the measurement point, determine the zero-sequence voltage value based on the voltage measurement value, and judge the ground fault through the zero-sequence voltage value, thereby improving the accuracy of the fault type judgment and further reducing the hardware cost.

[0138] In some embodiments, the measuring device includes a current transformer;

[0139] The first sampling module is used to acquire the current measurement value collected by the current transformer;

[0140] Fault detection module 102 includes:

[0141] The second processing module is used to determine the three-phase current values ​​based on the current measurement values.

[0142] In this embodiment, the fault detection module 102 includes a second processing module, which can receive current measurement values ​​from the second sampling module and calculate the three-phase current values ​​based on the current measurement values.

[0143] In this embodiment, the measuring device includes a current transformer, which can collect the current measurement value at the measuring point and transmit the current measurement value to the controller. The controller can calculate the corresponding three-phase current value at the measuring point based on the current measurement value.

[0144] In this embodiment of the application, a current transformer is set in the measuring device. The current transformer can collect the current measurement value at the measuring point, and the three-phase current value can be determined based on the current measurement value. The three-phase current value can be used to determine whether the grounding fault is a single-phase grounding fault, thereby improving the accuracy of fault type determination and further reducing hardware costs.

[0145] In some embodiments, the single-phase ground fault detection and processing apparatus 100 utilizing voltage and current time series information may optionally further include:

[0146] The second sampling module is used to acquire the change in three-phase current at each measurement point before and after the first switch is turned off;

[0147] The fault detection module 102 also includes:

[0148] The third processing module is used to determine the relative positional relationship between each measurement point and the fault point based on the changes in the three-phase current.

[0149] The third processing module is used to determine the fault section based on the relative positional relationships of multiple measurement points.

[0150] In this embodiment, the second sampling module is communicatively connected to the measuring device, and the second sampling module can acquire the three-phase current change at each measuring point before and after the first switch is turned off through the measuring device. The third processing module is used to determine the relative positional relationship between each measuring point and the fault point based on the three-phase current change acquired by the second sampling module, and then locate the fault section among multiple test sections based on the determined relative positional relationship.

[0151] In this embodiment, before isolating the faulty section by controlling the second and third switches to disconnect, it is necessary to locate the faulty section among multiple test sections. The criterion for locating the faulty section is the change in three-phase current. When a ground fault exists in the distribution line, the three-phase current value is collected by the measuring device at each measuring point and transmitted to the corresponding controller. The controller can determine the change in three-phase current based on the three-phase current value. After the controller determines the change in three-phase current, it can determine the relative positional relationship between the measuring point where the controller is located and the fault point based on the change in three-phase current. After determining the relative positional relationship between each measuring point and the fault point, the faulty section among multiple test sections can be located based on multiple relative positional relationships.

[0152] Specifically, the criterion for determining the fault section among multiple test sections is the positional relationship between each measurement point and the fault point. The criterion for the positional relationship between each measurement point and the fault point is the change in three-phase current. Therefore, the three-phase current value at each measurement point is collected by the measurement device, the change in three-phase current is determined by the corresponding controller, and the positional relationship between each measurement point and the fault point is determined based on the change in three-phase current.

[0153] In this embodiment, by determining the change in three-phase current at each measurement point, the relative positional relationship between the corresponding measurement point and the fault point can be determined based on the change in three-phase current. Based on the relative positional relationship between each measurement point and the fault point, the fault section can be located in multiple test sections, thereby improving the accuracy of locating the fault section.

[0154] In some embodiments, optionally, the third processing module is further configured to obtain the maximum and second largest changes in the three-phase current changes;

[0155] The third processing module is also used to determine that the measurement point is located on the power supply side of the fault point when the maximum change is greater than or equal to twice the second largest change.

[0156] The third processing module is also used to determine that the measurement point is located on the load side of the fault point when the maximum change is less than twice the second largest change.

[0157] In this embodiment, after the controller obtains the three-phase current change, it obtains the maximum and second-largest changes among the three-phase current changes, and compares the maximum and second-largest changes numerically. Based on the numerical comparison results, it determines the relative positional relationship between the measurement point and the fault point.

[0158] Specifically, if the maximum change is greater than or equal to twice the second largest change, the measurement point is determined to be located on the power supply side of the fault point; if the maximum change is less than twice the second largest change, the measurement point is determined to be located on the load side of the fault point.

[0159] It should be noted that each measurement point on the power distribution line is equipped with a measuring device and a controller. After the measuring device collects the three-phase current values, it transmits the three-phase current values ​​to the corresponding controller. The controller determines the change in three-phase current based on these values ​​and extracts the largest phase current change (the maximum change) and the second largest phase current change (the second largest change). If the maximum change is greater than or equal to twice the second largest change, the measuring point is located on the power supply side of the single-phase ground fault point. If the maximum change is less than twice the second largest change, the measuring point is located on the load side of the single-phase ground fault point.

[0160] In this embodiment, the maximum and second-largest changes in the three-phase current at the measurement point are extracted. By comparing the maximum and second-largest changes, the relative positional relationship between the measurement point and the fault point can be determined, which improves the accuracy of determining the relative positional relationship and thus improves the accuracy of locating the fault section in multiple test sections.

[0161] In some embodiments, optionally, the third processing module is further configured to determine the section to be measured between two adjacent measurement points as a fault section when one of the two adjacent measurement points is located on the power supply side of the fault point and the other measurement point is located on the load side of the fault point.

[0162] In this embodiment, after determining the relative positional relationship between each measurement point and the fault point, the relative positional relationship between each pair of adjacent measurement points and the fault point is detected. When it is determined that one of the two adjacent measurement points is located on the power supply side of the fault point and the other measurement point is located on the load side of the fault point, the fault section is determined to be located between the two adjacent measurement points.

[0163] In this embodiment of the application, after obtaining the relative positional 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 connection measurement point located on the load side of the fault point among two adjacent measurement points, then it is determined that the fault section is located between the two adjacent measurement points.

[0164] In some embodiments, the first duration may optionally range from 3 seconds to 8 seconds.

[0165] In this embodiment of the application, the first duration is the delay duration after the first switch is opened and then reclosed. By setting the value range of the first duration to be greater than or equal to 3 seconds, it can be ensured that the transient single-phase ground fault can be cleared within the first duration. Furthermore, by setting the value range of the first duration to be less than or equal to 8 seconds, it can be ensured that the power supply of the distribution line can be quickly restored after the transient single-phase ground fault is cleared.

[0166] like Figure 4 As shown, five switches are installed on the distribution line: PU1, PU2, PU3, PU4, and PU5. The first operation delay of the distribution line's outgoing protection is 10 seconds, and the reclosing delay of the outgoing protection 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 for load-side protection camera operation is 59 to 61 seconds. The power supply side protection delay of PU3 is 40 seconds, and the window position for load-side protection camera operation is 49 to 51 seconds. The power supply side protection delay of PU4 is 30 seconds, and the window position for load-side protection camera operation is 39 to 41 seconds. The power supply side protection delay of PU5 is 20 seconds, and the window position for load-side protection camera operation is 29 to 31 seconds.

[0167] It should be clarified that in the claims, description, and accompanying drawings of this application, the term "multiple" refers to two or more objects. Unless otherwise explicitly defined, the terms "upper," "lower," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description process, not to indicate or imply that the device or element referred to must have the described specific orientation, or be constructed and operated in a specific orientation. Therefore, these descriptions should not be construed as limitations on this application. The terms "connection," "installation," "fixing," etc., should be interpreted broadly. For example, "connection" can be a fixed connection between multiple objects, 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 those skilled in the art, the specific meaning of the above terms in this application can be understood based on the specific circumstances of the above data.

[0168] In the claims, description, and accompanying drawings of this application, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In the claims, description, and accompanying drawings of this application, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0169] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A single-phase grounding fault detection and processing device utilizing voltage and current time series information, characterized in that, Applied to power distribution lines, the power distribution lines are equipped with multiple measurement points and multiple switches. The multiple measurement points divide the power distribution lines into multiple test sections. Each measurement point is equipped with a switch. The single-phase grounding fault detection and processing device utilizing voltage and current time series information includes: The fault detection module is used to detect whether there is a single-phase grounding fault in the power distribution line; The control module is used to control the first switch among a plurality of switches to open when a single-phase ground fault exists in the power distribution line, and to control the first switch to reclose after a first time delay, wherein the first switch is the switch in the power distribution line that is closest to the power source side; The fault detection module is used to determine that the single-phase grounding fault is a transient fault after the first switch is reclosed and the power distribution line does not have the single-phase grounding fault. The fault detection module is used to determine that the single-phase grounding fault is a permanent fault when the first switch is reclosed and the single-phase grounding fault exists in the power distribution line. The fault detection module is used to identify faulty sections among the multiple test sections; The control module is used to control the second switch and the third switch to disconnect in order to isolate the fault section, wherein the second switch is the switch on the power supply side of the fault section, and the third switch is the switch on the load side of the fault section; The single-phase ground fault detection and processing device utilizing voltage and current time series information further includes: The second sampling module is used to acquire the change in three-phase current at each measurement point before and after the first switch is turned off; The fault detection module further includes: The third processing module is used to determine the relative positional relationship between each measurement point and the fault point based on the three-phase current change. The third processing module is used to determine the fault section based on the relative positional relationships between the multiple measurement points.

2. The single-phase grounding fault detection and processing device utilizing voltage and current time series information according to claim 1, characterized in that, The control module includes a first sub-control module and a second sub-control module, wherein the first sub-control module corresponds to the second switch and the second sub-control module corresponds to the third switch; The process by which the control module controls the second switch and the third switch to open includes: The first sub-control module is used to control the second switch to open; The second sub-control module is used to control the third switch to open when the first measurement point is in a state of three-phase undervoltage and three-phase undercurrent, where the first measurement point is the measurement point corresponding to the third switch.

3. The single-phase grounding fault detection and processing device utilizing voltage and current time series information according to claim 1, characterized in that, Multiple measuring devices are installed on the power distribution line, and the multiple measuring devices are respectively installed at multiple measuring points; The single-phase ground fault detection and processing device utilizing voltage and current time series information further includes: The first sampling module is used to acquire the zero-sequence voltage value collected by the measuring device; The fault detection module is used to determine that there is a grounding fault in the power distribution line when the zero-sequence voltage value is greater than the voltage setting value. The first sampling module is used to acquire the three-phase current values ​​collected by the measuring device; The fault detection module is used to determine whether the single-phase grounding fault exists in the power distribution line based on the three-phase current values.

4. The single-phase grounding fault detection and processing device utilizing voltage and current time series information according to claim 3, characterized in that, The fault detection module is used to determine that the power distribution line has a single-phase grounding fault when the current value of each phase in the three-phase current values ​​is less than or equal to the current setting value. The fault detection module is used to determine that the single-phase grounding fault does not exist in the power distribution line when any phase current value among the three-phase current values ​​is greater than the current setting value.

5. The single-phase grounding fault detection and processing device utilizing voltage and current time series information according to claim 3, characterized in that, The measuring device includes a voltage transformer; The first sampling module is used to acquire the voltage measurement value collected by the voltage transformer; The fault detection module includes: The first processing module is used to determine the zero-sequence voltage value based on the voltage measurement value.

6. The single-phase grounding fault detection and processing device utilizing voltage and current time series information according to claim 3, characterized in that, The measuring device includes a current transformer; The first sampling module is used to acquire the current measurement value collected by the current transformer; The fault detection module includes: The second processing module is used to determine the three-phase current value based on the current measurement value.

7. The single-phase grounding fault detection and processing device utilizing voltage and current time series information according to claim 1, characterized in that, The third processing module is also used to obtain the maximum and second largest changes in the three-phase current changes; The third processing module is also used to determine that the measurement point is located on the power supply side of the fault point when the maximum change is greater than or equal to twice the second largest change. The third processing module is also used to determine that the measurement point is located on the load side of the fault point when the maximum change is less than twice the second largest change.

8. The single-phase grounding fault detection and processing device utilizing voltage and current time series information according to claim 1, characterized in that, The third processing module is further configured to determine the section to be measured between two adjacent measurement points as the fault section when one of the two adjacent measurement points is located on the power supply side of the fault point and the other measurement point is located on the load side of the fault point.

9. The single-phase grounding fault detection and processing device utilizing voltage and current time series information 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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