Gridding protection method and apparatus for power distribution network, and device, medium and program product

Abstract

A gridding protection method and apparatus for a power distribution network, and a device, a medium and a program product. The method comprises: determining boundary switches from among switches in a power distribution network line (S110); on the basis of the boundary switches, dividing the power distribution network line, so as to determine load grids, branch line grids and main line grids (S120); on the basis of a preset load grid rule, determining a two-stage over-current protection mechanism for a boundary switch in each load grid (S130); on the basis of first protection configuration information in a power distribution network region corresponding to each branch line grid, determining a branch line protection action duration for boundary switches in the branch line grid (S140); on the basis of the branch line protection action duration, determining a two-stage over-current protection mechanism for the boundary switches in the branch line grid (S150); on the basis of second protection configuration information in a power distribution network region corresponding to each main line grid, determining a main line protection action duration for boundary switches in the main line grid (S160); and on the basis of the main line protection action duration, determining a directional pilot protection mechanism for the boundary switches in the main line grid (S170).

Description

Power grid mesh protection method, device, equipment, medium and program product

[0001] The present application claims priority to the Chinese patent application No. 202410909759.5 filed on July 5, 2024 with the China Patent Office, the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the field of power system relay protection, for example to a power grid mesh protection method, device, equipment, medium and program product. BACKGROUND

[0003] Relay protection is an important measure for detecting faults or abnormal conditions in a power system, thereby issuing an alarm signal, or directly isolating and removing the fault part. Therefore, corresponding relay protection is configured at each level of switch in the power grid, so that when a fault occurs in the power grid, each level of switch can be disconnected in time to reliably isolate the fault.

[0004] The traditional power grid is a single power source radial network. In the case of configuring corresponding relay protection for the traditional power grid, the substation outlet switch, branch switch and user boundary switch are usually configured with stage overcurrent protection according to a three-level coordination mode. That is, by setting corresponding overcurrent protection at the substation outlet switch, branch switch and user boundary switch, and setting the protection setting values and action times of each switch in coordination with each other. When the current reaches the protection setting value and the corresponding action time is experienced, each switch is disconnected to remove the fault.

[0005] However, with the rapid development of photovoltaic power generation, a large number of distributed power sources are also connected to the power grid, making the power grid change from a single power source radial network to a multi-power source network. After the power grid changes to a multi-power source network, the original short-circuit current distribution characteristics of the power grid are changed, making the original stage overcurrent protection less effective.

[0006] For example, distributed power sources can make the short-circuit current in the power grid larger, causing the switch to act out of turn, or make the short-circuit current smaller, making it difficult for the switch to remove the fault in time, or produce a reverse short-circuit current, causing the switch to malfunction.

[0007] At the present stage, in order to solve the problem of poor effect of relay protection in the multi-power source power grid line, protection devices are usually installed at each switch, and communication channels need to be established between each protection device to configure differential protection or longitudinal protection at each switch.

[0008] For example, the protection device corresponding to each switch needs to collect current information of all branches in the protection area to determine whether a short circuit occurs in the protection area. In the case of a short circuit in a branch, the switch corresponding to the branch timely cuts off the fault, and the switch of the branch timely feeds back a blocking signal to the upper-level switch, for example, a blocking signal to the switch on the main line to indicate that the switch corresponding to the branch has been disconnected, and the switch on the main line no longer performs a disconnection action in response to the blocking signal, and only the switch corresponding to the branch is disconnected to isolate the fault area; in the case where the switch on the main line does not receive the blocking signal, the switch on the main line is disconnected to isolate the fault area.

[0009] However, the method in the related art needs to establish a communication channel between each protection device so that the protection device of a lower-level switch can transmit a communication signal to the protection device of an upper-level switch, for example, a blocking signal from the protection device of a branch line switch to the protection device of a main line switch.

[0010] In the case where a new branch line is added in the power distribution network line, the protection on the main line needs to be reconfigured and set, so that the topology of this method has poor adaptability. SUMMARY

[0011] The present application aims to provide a power distribution network grid protection method, device, equipment, medium and program product.

[0012] According to an aspect of the present application, a power distribution network grid protection method is provided, which includes determining boundary switches from each switch of a power distribution network line. The power distribution network line is divided according to the boundary switches to determine a load grid, a branch line grid and a main line grid. The two-section overcurrent protection mechanism of the boundary switches in the load grid is determined according to a preset load grid rule. The branch line protection action time of the boundary switches of the branch line grid is determined according to first protection configuration information in the power distribution network area corresponding to the branch line grid. The two-section overcurrent protection mechanism of the boundary switches of the branch line grid is determined according to the branch line protection action time. The main line protection action time of the boundary switches of the main line grid is determined according to second protection configuration information in the power distribution network area corresponding to the main line grid. The directional pilot protection mechanism of the boundary switches of the main line grid is determined according to the main line protection action time.

[0013] The first protection configuration information is information of the protection mechanism of the boundary switches in the power distribution network area corresponding to the branch line grid whose protection mechanism has been determined; and the second protection configuration information is information of the protection mechanism of the boundary switches in the power distribution network area corresponding to the main line grid whose protection mechanism has been determined.

[0014] According to an aspect of the present application, a power distribution network grid protection device is provided, which comprises a boundary switch determination module, a grid division module, a load mechanism determination module, a branch line protection time determination module, a branch line mechanism determination module, a main line protection time determination module, and a main line mechanism determination module.

[0015] The boundary switch determination module is configured to determine boundary switches from each switch of the power distribution network line.

[0016] The grid division module is configured to divide the power distribution network line according to the boundary switches to determine a load grid, a branch line grid, and a main line grid.

[0017] The load mechanism determination module is configured to determine a two-section overcurrent protection mechanism of the boundary switches in the load grid according to a preset load grid rule; the branch line protection time determination module is configured to determine a branch line protection action time of the boundary switches of the branch line grid according to first protection configuration information in a power distribution network region corresponding to the branch line grid; the branch line mechanism determination module is configured to determine a two-section overcurrent protection mechanism of the boundary switches of the branch line grid according to the branch line protection action time; the main line protection time determination module is configured to determine a main line protection action time of the boundary switches of the main line grid according to second protection configuration information in a power distribution network region corresponding to the main line grid; and the main line mechanism determination module is configured to determine a directional pilot protection mechanism of the boundary switches of the main line grid according to the main line protection action time.

[0018] The first protection configuration information is information of protection mechanisms of the boundary switches in the power distribution network region corresponding to the branch line grid which have been determined; and the second protection configuration information is information of protection mechanisms of the boundary switches in the power distribution network region corresponding to the main line grid which have been determined.

[0019] According to an aspect of the present application, an electronic device is provided, which comprises one or more processors, a storage device configured to store one or more programs, and when the one or more programs are executed by the one or more processors, the one or more processors implement the method as described above.

[0020] According to an aspect of the present application, a computer readable medium is provided, which stores a computer program, and when the computer program is executed by a processor, the method as described above is implemented.

[0021] According to an aspect of the present application, a computer program product is provided. The computer program product comprises a computer program stored on a computer readable storage medium, and the computer program comprises program instructions, and when the program instructions are executed by a computer, the computer executes the method as described above. Advantages

[0022] By adopting the power distribution network gridding protection method described above, the power distribution network line is divided into a load grid, a branch line grid and a main line grid. And the protection mechanism corresponding to the boundary switch of each grid is set in turn. For the branch line grid, the branch line protection action time length of the boundary switch of the branch line grid is determined according to the first protection configuration information in the power distribution network region of the branch line grid; for the main line grid, the main line protection action time length of the boundary switch of the main line grid is determined according to the second protection configuration information in the power distribution network region of the main line grid.

[0023] In this way, it is not necessary to establish a communication channel for communication between each switch in the power distribution network line, and it is not necessary to transmit a blocking signal between each switch, but only the directional pilot protection needs to be configured at the boundary switch of the main line grid, and the original protection configuration of the branch line in the main line grid does not need to be modified, which greatly improves the adaptability of the protection to the frequent changes of the power distribution network topology, and only the switch quantity signal for judging the fault direction needs to be transmitted between the boundary switches of the main line grid, which greatly reduces the requirement for communication performance. BRIEF DESCRIPTION OF DRAWINGS

[0024] Fig. 1 is a flowchart of the power distribution network gridding protection method provided by the embodiment of the present application;

[0025] Fig. 2 is an example diagram of a power distribution network line after the grid division provided by the embodiment of the present application;

[0026] Fig. 3 is a flowchart of determining the boundary switch in step S110 provided by the embodiment of the present application;

[0027] Fig. 4 is a flowchart of determining the branch line boundary switch in step S112 provided by the embodiment of the present application;

[0028] Fig. 5 is a flowchart of dividing the grid in step S120 provided by the embodiment of the present application;

[0029] Fig. 6 is a flowchart of determining the branch line protection action time length in step S140 provided by the embodiment of the present application;

[0030] Fig. 7 is an example diagram of the respective protection mechanisms corresponding to each grid of the power distribution network line example provided by the embodiment of the present application;

[0031] Fig. 8 is a flowchart of determining the overcurrent protection mechanism of the branch line grid in step S150 provided by the embodiment of the present application;

[0032] Fig. 9 is a flowchart of determining the main line protection action time length in step S160 provided by the embodiment of the present application;

[0033] Fig. 10 is a flowchart of determining the protection mechanism of the substation outgoing switch provided by the embodiment of the present application;

[0034] Fig. 11 is a flow diagram of determining the length of the line protection action according to an embodiment of the present application;

[0035] Fig. 12 is a block diagram of a power distribution network meshed protection device according to an embodiment of the present application;

[0036] Fig. 13 is a schematic diagram of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0037] Example embodiments now will be described more fully hereinafter with reference to the accompanying drawings. Example embodiments, however, can be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of example embodiments to those skilled in the art. Like reference numerals refer to like elements throughout the several views.

[0038] The described features, structures, or characteristics can be combined in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the disclosure. One skilled in the relevant art will recognize, however, that the technology can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In these instances, well-known structures, methods, devices, implementations, materials, and so forth can not be described in detail.

[0039] In addition, the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting; it will be apparent that the technology can be practiced in other embodiments that are within the scope of the technology. For example, the steps recited in any of the methods can be ordered in different sequences, or additional steps can be added or removed as appropriate. In addition, the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting; it will be apparent that the technology can be practiced in other embodiments that are within the scope of the technology. For example, the steps recited in any of the methods can be ordered in different sequences, or additional steps can be added or removed as appropriate.

[0040] The terms "first", "second", and the like, in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of use in either order.

[0041] The technical solutions of the present application will be described clearly and completely below with reference to the drawings of the embodiments of the present application. The described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of the present application.

[0042] The embodiment of the present application provides a power distribution network grid protection method. Referring to FIG. 1, the power distribution network grid protection method is executed by an electronic device, and the method comprises the following steps: step S110, step S120, step S130, step S140, step S150, step S160 and step S170.

[0043] In step S110, a boundary switch is determined from each switch of a power distribution network line.

[0044] According to an example embodiment, the power distribution network line is a power network that accepts electric energy from a power transmission network or a regional power plant, and then distributes the electric energy to various users through power distribution facilities or step by step according to voltage.

[0045] The power distribution network line is usually a tree-shaped radial network, as shown in FIG. 2. Electric energy is output from a transformer substation bus, and then transmitted to users through a main line, a branch line and an end load line. The main line in the power distribution network line is equivalent to a trunk. The trunk can be connected to a branch, which is equivalent to a branch line. The branch can be connected to other small branches, which are equivalent to end load lines.

[0046] Switches are usually arranged on the main line, the branch line and the end load line of the power distribution network line. For example, as shown in FIG. 2, the transformer substation outgoing line switch, the sectionalizing switch and the tie switch are usually arranged on the main line of the power distribution network; the branch switch is usually arranged on the branch line of the power distribution network; and the user boundary switch is usually arranged on the end load line of the power distribution network.

[0047] The transformer substation outgoing line switch refers to a switch at the first end of the main line in the transformer substation. The sectionalizing switch is used to divide the main line into several power supply areas. The tie switch is a switch that transfers line load to other power grid power sources in the case of power failure. It is worth noting that the tie switch is usually in an open state in the normal operation, and is closed to connect the line load to other power grid power sources in the case of transformer substation failure.

[0048] In the embodiment of the present application, in step S110, the electronic device determines the boundary switch from each switch of the power distribution network line. Specifically, the electronic device can directly determine the transformer substation outgoing line switch, the sectionalizing switch, the tie switch, the branch switch and the user boundary switch as the boundary switch; or the electronic device can screen the boundary switch from the transformer substation outgoing line switch, each sectionalizing switch, each tie switch, each branch switch and each user boundary switch.

[0049] Exemplarily, in step S110, for the power distribution network circuit shown in FIG. 2, the electronic device can determine the substation outgoing line switch, the sectionalizing switch 1, the tie switch, the user boundary switch 1, the branch switch 2, the user boundary switch 2, the user boundary switch 3, the user boundary switch 4, the branch switch 3, the user boundary switch 5, and the user boundary switch 6 as the boundary switches respectively.

[0050] In step S120, the power distribution network circuit is divided according to the boundary switches to determine the load grid, the branch line grid, and the main line grid.

[0051] According to an example embodiment, in step S120, the electronic device can divide the power distribution network circuit according to the selected boundary switches to divide the power distribution network circuit into the load grid, the branch line grid, and the main line grid.

[0052] According to an example embodiment, in step S120, the load grid is a power distribution network region corresponding to the boundary switch closest to the load and the downstream region of the boundary switch. The downstream region is a region determined according to the current flow direction of the power grid power source. Exemplarily, the user boundary switch 1 in FIG. 2 is the boundary switch closest to the load 1, and the current in the power grid power source flows from the user boundary switch 1 to the load 1. The downstream region of the user boundary switch 1 is a region including all the loads connected by the user boundary switch and the circuit.

[0053] According to an example embodiment, in step S120, the branch line grid includes a power distribution network region corresponding to the branch line boundary switch and the downstream region of the boundary switch. The branch line boundary switch is used to control the connection and disconnection between the branch line and the main line. Exemplarily, the branch switch 2 in FIG. 2 is used to control whether the branch line is connected to the main line, and is the branch line boundary switch. The branch switch 2 and the downstream region of the branch switch 2 are divided into a branch line grid.

[0054] According to an example embodiment, in step S120, the branch line grid further includes a power distribution network circuit corresponding to the boundary switch closest to the distributed power source and the downstream region of the boundary switch. For example, the user boundary switch 6 shown in FIG. 2 is connected to the distributed power source, and the circuit between the user boundary switch 6 and the distributed power source is divided into a branch line grid by the electronic device.

[0055] According to an example embodiment, in step S120, the main line grid is a power distribution network region corresponding to two adjacent main line boundary switches. The main line boundary switch is a boundary switch located on the main line. For example, as shown in FIG. 2, the electronic device divides the substation outgoing line switch and the sectionalizing switch 1 into a main line grid, and divides the sectionalizing switch 1 and the tie switch into a main line grid.

[0056] In step S130, two-section overcurrent protection mechanisms of boundary switches in the load grid are determined according to preset load grid rules.

[0057] According to an example embodiment, for a load grid, two-section overcurrent protection can be configured for boundary switches in the load grid. The two-section overcurrent protection includes I-section overcurrent protection and II-section overcurrent protection.

[0058] According to an example embodiment, the preset load grid rules are preset protection configuration rules, specifically including setting the I-section overcurrent protection of the load grid as non-delay overcurrent protection, and setting the II-section overcurrent protection of the load grid as preset load delay time length.

[0059] The I-section overcurrent protection is used for short-circuit fault in the load grid, and the fault is cut off without delay; the II-section overcurrent protection is used for abnormal disturbance in the load grid, and the abnormal disturbance can disappear by itself within the II-section load action time length, so that the II-section overcurrent protection does not act, and the load can continue to operate normally.

[0060] According to an example embodiment, in step S130, for the load grid, the electronic device can directly determine the two-section overcurrent protection mechanism of each load grid according to the preset load grid rules. The two-section overcurrent protection mechanism includes the I-section load action time length of the I-section overcurrent protection and the II-section load action time length of the II-section overcurrent protection. It is worth noting that the I-section load action time length of the load grid is 0, and the II-section load action time length is preset load delay time length.

[0061] Then, the electronic device can feed back the two-section overcurrent protection mechanism of the load grid to the worker, and the worker can configure corresponding relay protection for the boundary switches of each load grid.

[0062] In step S140, the branch line protection action time length of the boundary switches of the branch line grid is determined according to the first protection configuration information in the power distribution grid area corresponding to the branch line grid.

[0063] The first protection configuration information is the protection mechanism information of the boundary switches in the power distribution grid area corresponding to the branch line grid, whose protection mechanism has been determined.

[0064] For example, for the branch line grid corresponding to branch switch 2, the branch line grid includes the load grid corresponding to user boundary switch 2, the load grid corresponding to user boundary switch 3, and the load grid corresponding to user boundary switch 4. The protection mechanisms of user boundary switch 2, user boundary switch 3, and user boundary switch 4 have been determined by the electronic device in step S130.

[0065] That is, the first protection configuration information corresponding to the branch switch 2 includes the one-phase load action time and the two-phase load action time of the user boundary switch 2, the one-phase load action time and the two-phase load action time of the user boundary switch 3, and the one-phase load action time and the two-phase load action time of the user boundary switch 4.

[0066] For the case where there is no load grid in the branch grid, the first protection configuration information corresponding to the branch grid is an empty set.

[0067] In step S150, according to the branch protection action time, the two-phase overcurrent protection mechanism of the boundary switch of the branch grid is determined.

[0068] According to the example embodiment, the load grid determines the corresponding protection mechanism in the manner of step S130 described above. In step S140, the electronic device can determine the branch protection action time of the boundary switch of the branch grid according to the first protection configuration information; and in step S150, the electronic device can determine the protection mechanism of the boundary switch of the branch grid according to the branch protection action time.

[0069] According to the example embodiment, the boundary switch of the branch grid is configured with two-phase overcurrent protection. The branch protection action time corresponds to the one-phase branch action time and the two-phase branch action time. When the current reaches the setting value of the I-phase overcurrent protection, the boundary switch of the branch grid performs the disconnecting action after the one-phase branch action time. When the current reaches the setting value of the II-phase overcurrent protection, the boundary switch of the branch grid performs the disconnecting action after the two-phase branch action time.

[0070] In order to reduce the power outage range during a fault and ensure that the fault can be reliably removed, in the case where a fault occurs in the branch grid, the boundary switch of the branch grid needs to be disconnected in time to remove the fault point in the case where the boundary switch of the load grid or other lower-level switches cannot timely disconnect to remove the fault.

[0071] Therefore, in the embodiment of the present application, the one-phase branch action time and the two-phase branch action time can be determined according to the first protection configuration information in the branch grid. For example, referring to FIG. 2, for the branch switch 2, the electronic device can set, in step S130, the one-phase branch action time of the branch switch 2 to be greater than the one-phase load action time of each lower-level boundary switch, and the two-phase branch action time to be greater than the two-phase load action time of each lower-level boundary switch.

[0072] In this way, in the case of a fault occurring in the load grid corresponding to the user boundary switch 2, the two-section overcurrent protection devices of the user boundary switch 2 can cut off the fault in the branch line protection action time; in the case that the user boundary switch 2 does not cut off the fault in time after the branch line protection action time, the branch switch 2 can act to reliably cut off the fault.

[0073] In step S160, the main line protection action time of the boundary switch of the main line grid is determined according to the second protection configuration information in the power distribution grid area corresponding to the main line grid.

[0074] The second protection configuration information is information of the protection mechanism of the boundary switch in the power distribution grid area corresponding to the main line grid, which has been determined.

[0075] In the above steps S130, S140 and S150, the electronic device determines the protection mechanism corresponding to the boundary switch of the load grid and the boundary switch of the branch line grid, respectively. That is, the second protection configuration information corresponding to the main line grid includes the load protection action time of the boundary switch of each load grid and the branch line protection action time of the boundary switch of each branch line grid in the power distribution grid area.

[0076] For example, referring to FIG. 2, for the main line grid between the substation outgoing switch and the section switch 1, the power distribution grid area corresponding to the main line grid includes the load grid corresponding to the user boundary switch 1. Therefore, the first protection configuration information corresponding to the main line grid includes the one-section protection action time and the two-section protection action time of the user boundary switch 1.

[0077] For the case that there is no load grid and no branch line grid in the main line grid, the second protection configuration information corresponding to the main line grid is an empty set.

[0078] In step S170, the directional pilot protection mechanism of the boundary switch of the main line grid is determined according to the main line protection action time.

[0079] According to the example embodiment, in step S160, the electronic device can determine the main line protection action time of each main line grid according to the protection mechanism set by the boundary switch of each load grid and the boundary switch of each branch line grid. In step S170, the electronic device can determine the directional pilot protection mechanism of the boundary switch of the main line grid according to the main line protection action time.

[0080] According to the example embodiment, the directional pilot protection is a protection device that causes both sides of the switch to trip quickly when a fault occurs in the line. It uses a specific relationship between the two sides of the line as a criterion. That is, both sides transmit the discriminant to the opposite side through the channel, and then both sides respectively determine the intra-zone fault or the extra-zone fault according to the relationship between the discriminant of the opposite side and the discriminant of the local side.

[0081] For the case that there is a lower-level grid such as a load grid and / or a branch grid in the main-line grid, in the case that the two boundary switches of the main-line grid judge that it is a zone fault, the fault can be first removed by the lower-level boundary switch in the main-line grid. In the case that the lower-level boundary switch does not timely remove the fault, the two boundary switches of the main-line grid are then disconnected to remove the entire zone, wherein the lower-level boundary switch in the main-line grid refers to the boundary switch of the lower-level grid.

[0082] Therefore, in order to facilitate reducing the outage range in the case of a fault, in the embodiment of the present application, the main-line action time length of the boundary switch of the main-line grid is determined according to the protection action time length of the lower-level boundary switch in the main-line grid, so that the scheme of preferentially removing the fault by the lower-level boundary switch is realized by utilizing the cooperation of the protection action time lengths between the boundary switches.

[0083] For example, referring to FIG. 2, for the main-line grid between the substation outgoing switch and the sectionalizing switch 1, in the case that there is only the load grid corresponding to the user boundary switch 1 in the main-line grid, in step S160, the electronic device can set the main-line protection action time length of the directional pilot protection of the substation outgoing switch and the sectionalizing switch 1, so that the main-line protection action time length is greater than the one-section load action time length of the user boundary switch 1.

[0084] For example, in the case that a fault occurs in the load grid corresponding to the user boundary switch 1, within the main-line protection action time length, the fault is removed by the user boundary switch 1, after the user boundary switch 1 acts, the fault is isolated from other grids, the enable signals of the substation outgoing switch and the sectionalizing switch 1 are returned immediately, and the main-line grid protection does not act. For the case that the user boundary switch 1 does not act within the main-line protection action time length, that is, the user boundary switch 1 does not timely remove the fault, the fault time length reaches the main-line protection action time length of the directional pilot protection device set by the substation outgoing switch and the sectionalizing switch 1, and the fault in the load grid corresponding to the user boundary switch 1 is removed by the substation outgoing switch and the sectionalizing switch 1, so that the fault of the load grid corresponding to the user boundary switch 1 does not affect the devices in other main-line grids in the power distribution network line, nor does it affect the substation.

[0085] In the related art, in order to reduce the outage range in the case of a fault and ensure that the fault can be reliably removed, the boundary switch of the branch grid needs to communicate with the boundary switch of the main-line grid and send a blocking signal to the main-line grid.

[0086] However, in the embodiments of the present application, only the protection action time length of the boundary switches of the main line grid and the protection action time length of each boundary switch of the lower level (for example, in the case where the main line grid comprises a branch line grid and a load grid, the protection action time length of each boundary switch of the lower level comprises the branch line protection action time length of the boundary switches of the branch line grid and the load protection action time length of the boundary switches of the load grid) are matched to automatically remove the fault by the boundary switches of the main line grid in the case where the fault occurs in the lower level line and the boundary switches of the lower level do not timely remove the fault, without the need to establish communication between each switch and without the need to transmit the blocking signal between each switch.

[0087] According to some embodiments, the directional pilot protection can employ a permissive directional pilot protection. Specifically, determining the directional pilot protection mechanism of the main line grid in step S170 further comprises determining a signal sending mechanism of the main line grid and an action mechanism of the main line grid, and determining the directional pilot protection mechanism of the main line grid according to the signal sending mechanism of the main line grid and the action mechanism of the main line grid.

[0088] According to example embodiments, the electronic device can determine a preset signal sending mechanism as the signal sending mechanism of the main line grid. The preset signal sending mechanism comprises: sending a first permissive signal to each boundary switch in the main line grid in the case where the boundary switches of the main line grid satisfy the flow criterion and the fault direction points to the main line grid; sending a second permissive signal to each boundary switch in the main line grid in the case where the boundary switches of the main line grid do not satisfy the flow criterion; and not sending a permissive signal in the case where the boundary switches of the main line grid satisfy the flow criterion and the fault direction does not point to the main line grid, the permissive signal comprising the first permissive signal and the second permissive signal.

[0089] According to example embodiments, when the current flowing through the boundary switches of the main line grid reaches a preset value, it is indicated that the boundary switches of the main line grid satisfy the flow criterion.

[0090] Exemplarily, in the case that the staff configures the directional pilot protection on the boundary switches of the main line grid according to the signal sending mechanism of the boundary switches of the main line grid, for the main line grid corresponding to the substation outgoing switch and the sectionalizing switch 1, the protection device corresponding to the substation outgoing switch determines in real time whether the substation outgoing switch satisfies the current criterion and whether the fault direction is directed to the grid. The protection device corresponding to the sectionalizing switch 1 also determines in real time. In the case that the protection device corresponding to the substation outgoing switch determines that the boundary switch satisfies the current criterion and the fault direction is directed to the main line grid, the protection device sends the first permission signal to the sectionalizing switch 1; in the case that the protection device corresponding to the substation outgoing switch determines that the current criterion of the boundary switch is not satisfied, the protection device sends the second permission signal to the sectionalizing switch 1; in the case that the protection device corresponding to the substation outgoing switch determines that the current criterion of the boundary switch is satisfied and the fault direction is not directed to the grid, neither the first permission signal nor the second permission signal is sent.

[0091] According to an example embodiment, the electronic device can determine a preset action mechanism as the action mechanism of the boundary switch of the main line grid. The preset action mechanism includes that the boundary switch of the main line grid determines whether a first preset action exit condition is satisfied and whether a second preset action exit condition is satisfied; in the case that the first preset action exit condition is satisfied or the second preset action exit condition is satisfied, the directional pilot protection device acts, that is, the boundary switch of the main line grid is opened to remove the fault.

[0092] The first preset action exit condition includes that the protection starting element of the boundary switch satisfies the starting condition; and the boundary switch sends the first permission signal; and permission signals sent by all other boundary switches in the main line grid are received; and the fault duration reaches the main line protection action duration corresponding to the boundary switch. It is worth noting that in the case that the first permission signal sent by any boundary switch is received or the second permission signal sent by the any boundary switch is received, it means that the permission signal sent by the any boundary switch is received.

[0093] The second preset action exit condition includes that the protection starting element of the boundary switch satisfies the starting condition; and the boundary switch sends the second permission signal; and permission signals sent by all other boundary switches in the main line grid are received; and at least one first permission signal exists in the received permission signals; and the fault duration reaches the main line protection action duration corresponding to the boundary switch.

[0094] The starting element of the directional pilot protection can specifically include an overcurrent starting element and / or a low-voltage starting element.

[0095] For the case that the starting element corresponding to the boundary switch configured with directional longitudinal protection includes both overcurrent starting element and low voltage starting element, in the case that the overcurrent starting element meets the preset current starting element and / or the low voltage starting element meets the preset voltage starting element, that is, the protection starting element of the boundary switch meets the starting condition.

[0096] By adopting the power distribution network meshing protection method described above, the power distribution network line is divided into a load mesh, a branch line mesh and a main line mesh. And the protection mechanism corresponding to the boundary switch of each mesh is sequentially set. For the branch line mesh, the branch line protection action time length of the boundary switch of the branch line mesh is determined according to the first protection configuration information in the power distribution network region of the branch line mesh; for the main line mesh, the main line protection action time length of the boundary switch of the main line mesh is determined according to the second protection configuration information in the power distribution network region of the main line mesh.

[0097] In this way, it is not necessary to establish a communication channel for communication between each switch in the power distribution network line, and it is not necessary to transmit a blocking signal between each switch, but only the direction longitudinal protection is configured at the boundary switch of the main line mesh, and the switch quantity signal for judging the fault direction is transmitted, and the requirement for communication performance is low.

[0098] The embodiment of the present application also does not need to transmit a blocking signal or current information between each boundary switch, but only through the protection action time length of the boundary switch between each mesh to cooperate with each other, so that in the case of line fault, the boundary switch of the mesh to which the fault line belongs is sequentially removed according to the order of load mesh, branch line mesh and main line mesh.

[0099] Therefore, for the technical solution of the embodiment of the present application, in the case of increasing or reducing branches of the main line mesh, each boundary switch with determined protection mechanism does not need to be reconfigured and set, but only the protection of the increased or reduced branch needs to be configured and set, and the topology adaptation ability is strong.

[0100] In addition, by dividing the power distribution network line into a main line mesh, a branch line mesh and a load mesh, in the case of line fault, only the fault mesh needs to be isolated, so that the fault isolation range is small.

[0101] Moreover, in the embodiment of the present application, no matter how long or short the power distribution network line is, only three levels of main line mesh, branch line mesh and load mesh are divided in the power distribution network line, so that the cooperation level of the protection action time length of the boundary switch of each mesh is limited to not higher than three levels, thereby facilitating the shortening of the fault removal time length.

[0102] According to some embodiments, referring to FIG. 3, in the step S110, the boundary switches are determined from the switches of the power distribution network line, which can specifically include a step S111, a step S112 and a step S113.

[0103] In the step S111, the main line boundary switches are determined according to the main line switches on the main line of the power distribution network line.

[0104] According to the example embodiments, the boundary switches can be divided into the main line boundary switches, the branch line boundary switches and the load boundary switches according to the setting positions of the switches. The electronic device can determine the boundary switches along the main line, the branch lines and the terminal load lines in sequence. The switches determined on the main line are the main line boundary switches, the switches determined on the branch lines are the branch line boundary switches, and the switches determined on the load boundary switches are the load boundary switches.

[0105] According to the example embodiments, the main line switches on the main line of the power distribution network line can specifically include the substation outgoing line switches, the sectionalizing switches and the tie switches. As shown in FIG. 2.

[0106] According to some embodiments, in the step S111, the electronic device can determine each main line switch as a boundary switch.

[0107] According to some embodiments, in the step S111, the electronic device determining the main line boundary switches can further include determining, from the main line switches along the main line of the power distribution network line, the main line switches satisfying the preset threshold condition as the main line boundary switches, starting from the substation outgoing line switch.

[0108] The preset threshold condition is that the total load capacity of the power distribution line section between the two adjacent main line boundary switches exceeds a preset load capacity value, or the number of branch lines connected in the power distribution line section is not less than a preset branch line number.

[0109] Exemplarily, the substation outgoing line switch, the sectionalizing switch 1, the sectionalizing switch 2, the sectionalizing switch 3, …, the sectionalizing switch n are sequentially arranged on the main line along the current flow direction. The electronic device determines the substation outgoing line switch as the main line boundary switch, starting from the substation outgoing line switch. Then, the electronic device determines whether the sectionalizing switch 1 and the current boundary switch satisfy the preset threshold condition according to the current boundary switch, that is, whether the total load capacity between the substation outgoing line switch and the sectionalizing switch 1 exceeds the preset load capacity value, and whether the number of branch lines connected in the power distribution line section between the substation outgoing line switch and the sectionalizing switch 1 is not less than the preset branch line number. In the case that the current boundary switch and the sectionalizing switch 1 do not satisfy the preset threshold condition, the electronic device determines whether the current boundary switch and the sectionalizing switch 2 satisfy the preset threshold condition, that is, whether the substation outgoing line switch and the sectionalizing switch 2 satisfy the preset threshold condition.

[0110] In the case that the preset threshold condition is met between the substation outgoing switch and the section switch 2, the section switch 2 is set as the main line boundary switch. Then the electronic device judges whether the preset threshold condition is met between the section switch 3 and the current boundary switch (i.e. the section switch 2), and so on. Until the electronic device judges whether the preset threshold condition is met between the section switch n and the current boundary switch, the section switch n is directly determined as the main line boundary switch regardless of whether the preset threshold condition is met between the section switch n and the current boundary switch.

[0111] In step S112, the branch switches on the branch lines of the distribution network line and the boundary switches connected with the distributed power sources are determined as the branch line boundary switches.

[0112] The branch switch is a switch for controlling the connection between the branch line and the main line.

[0113] According to the example embodiment, in step S112, the electronic device can determine each branch switch on the branch line of the distribution network line as the branch line boundary switch, and determine the boundary switch connected with the distributed power source as the branch line boundary switch.

[0114] For example, in the distribution network line shown in FIG. 2, the electronic device can determine the user boundary switch 6 as the branch line boundary switch, and determine the branch switch 1, the branch switch 2 and the branch switch 3 as the branch line boundary switches.

[0115] According to some embodiments, referring to FIG. 4, in step S112, the electronic device determining the branch line boundary switch can further include step S1121 and step S1122.

[0116] In step S1121, a target branch line is determined from each branch line.

[0117] According to the example embodiment, the target branch line is the branch line in which there are at least two main line switches on the main line section between the branch line and the substation bus. For example, the branch line corresponding to the branch switch 1 shown in FIG. 2, there is only one substation outgoing switch on the main line between the branch line and the substation bus, and the branch line corresponding to the branch switch 1 does not belong to the target branch line. For the branch line corresponding to the branch switch 2 and the branch switch 3, both belong to the target branch line.

[0118] In step S1122, the branch switch in the target branch line and the boundary switch connected with the distributed power source are determined as the branch line boundary switch.

[0119] According to an example embodiment, the electronic device determines the target branch line in step S1121, and then determines the branch switch corresponding to each target branch line as the branch line boundary switch and determines the interface switch connected with the distributed power supply as the branch line boundary switch in step S1122.

[0120] In this way, the branch switch of the branch line closest to the transformer substation is not provided with a corresponding protection, so that the protection action time of the outgoing switch of the transformer substation is shortened, and in the case that the power distribution line closest to the transformer substation fails, the transformer substation can timely cut off the fault by the outgoing switch of the transformer substation, thereby reducing the probability of the impact of short-circuit current on the transformer in the transformer substation.

[0121] In step S113, the load boundary switch is determined according to each load switch connected with the load in the power distribution network line.

[0122] According to an example embodiment, the electronic device determines the boundary switch on the branch line and the boundary switch on the main line in steps S111 and S112. For the switch connected with the load, that is, for the user interface switch in the terminal load line, the electronic device determines each user interface switch as the load boundary switch in step S113.

[0123] According to some embodiments, for the branch line with a complex topology of the power distribution network line, a plurality of terminal load lines can also be merged to determine the upstream common branch switch of the plurality of terminal load lines as the load boundary switch. For example, the branch line a is connected with a small branch line a1, the small branch line a1 is connected with a plurality of terminal load lines, and the small branch line a1 is configured with a branch switch a1 at the first end, and the branch switch a1 is the upstream common branch switch of the plurality of terminal load lines. Therefore, in step S113, the electronic device can determine the branch switch a1 as the load boundary switch of the terminal load lines.

[0124] According to some embodiments, referring to FIG. 5, in the above step S120, the power distribution network line is divided according to the boundary switch to determine the load grid, the branch line grid and the main line grid, which can specifically include steps S121, S122, S123, S124, S125 and S126.

[0125] In step S121, the first boundary switch is determined from the boundary switches.

[0126] According to an example embodiment, the first boundary switch is a boundary switch in a downstream power distribution network region without other boundary switches, and a boundary switch in the downstream power distribution network region without a large-capacity distributed power supply. For example, referring to FIG. 2, in the power distribution network circuit shown in FIG. 2, there is no other boundary switch in the downstream power distribution network region corresponding to each of the user boundary switch 1, the user boundary switch 2, the user boundary switch 3, the user boundary switch 4, and the user boundary switch 5, and there is no large-capacity distributed power supply in the downstream power distribution network region, and thus the user boundary switch 1, the user boundary switch 2, the user boundary switch 3, the user boundary switch 4, and the user boundary switch 5 are first boundary switches.

[0127] According to an example embodiment, in step S121, the electronic device can determine the first boundary switch, and then the electronic device can determine the load grid according to the first boundary switch.

[0128] In step S122, the first boundary switch and the downstream power distribution network region of the first boundary switch are divided into the load grid.

[0129] For example, as shown in FIG. 2, in step S122, the electronic device can divide the user boundary switch 1 and the downstream power distribution network region of the user boundary switch 1 into the load grid 1, divide the user boundary switch 2 and the downstream power distribution network region of the user boundary switch 2 into the load grid 2, divide the user boundary switch 3 and the downstream power distribution network region of the user boundary switch 3 into the load grid 3, divide the user boundary switch 4 and the downstream power distribution network region of the user boundary switch 4 into the load grid 4, and divide the user boundary switch 5 and the downstream power distribution network region of the user boundary switch 5 into the load grid 5.

[0130] In step S123, a second boundary switch is determined from the boundary switches, and the second boundary switch is a boundary switch satisfying a preset division condition.

[0131] In step S124, the second boundary switch and the downstream power distribution network region of the second boundary switch are divided into the branch line grid.

[0132] According to an example embodiment, in step S123, the preset division condition includes a first preset division condition and a second preset division condition. The first preset division condition is that the boundary switch is located on a non-main line in the power distribution network circuit, and there is a load grid in the downstream power distribution network region of the boundary switch.

[0133] The second preset division condition is that the boundary switch is located on a non-main line in the power distribution network circuit, and there is a large-capacity distributed power supply in the downstream power distribution network region of the boundary switch.

[0134] According to the example embodiment, in step S123, the electronic device can determine the boundary switches located on the non-main line, and then screen the boundary switches from the non-main line, in which the downstream power distribution network region has a load grid or a large-capacity distributed power source, to determine the second boundary switch.

[0135] For example, as shown in FIG. 2, the branch switch 2, the branch switch 3, the user boundary switch 1, the user boundary switch 2, the user boundary switch 3, the user boundary switch 4, the user boundary switch 5, and the user boundary switch 6 are located on the non-main line of the power distribution network line. The downstream power distribution network region of the branch switch 2 and the branch switch 3 has a load grid, and the downstream power distribution network region of the user boundary switch 6 has a large-capacity distributed power source.

[0136] Therefore, in step S123, the electronic device determines the branch switch 2, the branch switch 3, and the user boundary switch 6 as the second boundary switch.

[0137] According to the example embodiment, in step S124, the electronic device determines the second boundary switch and the downstream power distribution network region of the second boundary switch as the branch line grid.

[0138] In step S125, the third boundary switch is determined from the boundary switches.

[0139] According to the example embodiment, the third boundary switch is the boundary switch located on the main line. For example, the substation outlet switch, the sectionalizing switch 1, and the tie switch shown in FIG. 2. In step S125, the electronic device determines the boundary switch located on the main line as the third boundary switch.

[0140] In step S126, the power distribution network region between the adjacent two third boundary switches in the power distribution network is divided into the main line grid.

[0141] According to the example embodiment, in step S126, the electronic device divides the power distribution network region between the adjacent two second boundary switches into one main line grid. For example, as shown in FIG. 2, the power distribution network region between the substation outlet switch and the sectionalizing switch 1 is divided into one main line grid, and the power distribution network region between the sectionalizing switch 1 and the tie switch is divided into one main line grid.

[0142] Based on the above embodiment, after the electronic device divides the load grid, the branch line grid, and the main line grid according to the boundary switches in step S120, the protection mechanism of the respective boundary switches corresponding to each grid can be set.

[0143] According to some embodiments, for the branch grid, referring to FIG. 6, in step S140, according to the first protection configuration information in the power distribution network area corresponding to the branch grid, the branch protection action time length of the branch boundary switch is determined, including step S141, step S142a and step S142b.

[0144] In step S141, it is judged whether there is a branch lower-level grid in the branch grid.

[0145] According to example embodiments, the branch lower-level grid is other grid contained in the power distribution network area corresponding to the branch grid.

[0146] Exemplarily, as shown in FIG. 2 and FIG. 7, for the branch grid corresponding to branch switch 2, the power distribution network area corresponding to the branch grid contains the load grid corresponding to user boundary switch 2, the load grid corresponding to user boundary switch 3 and the load grid corresponding to user boundary switch 4, so the branch lower-level grid of the branch grid corresponding to branch switch 2 includes the load grid corresponding to user boundary switch 2, the load grid corresponding to user boundary switch 3 and the load grid corresponding to user boundary switch 4.

[0147] According to some embodiments, in step S141, the electronic device can directly identify whether there is a branch lower-level grid in the branch grid according to the power distribution network circuit after the grid division, or can judge whether there is a branch lower-level grid in the branch grid according to the first protection configuration information. For example, in the case of empty first protection configuration information, it means that there is no branch lower-level grid in the branch grid; in the case of non-empty first protection configuration information, it means that there is a branch lower-level grid in the branch grid.

[0148] In step S141, when the electronic device judges that there is no branch lower-level grid in the branch grid, the electronic device determines the one-segment branch action time length and the two-segment branch action time length of the boundary switch of the branch grid, which can specifically include step S142a.

[0149] In step S142a, the first preset time length is determined as the one-segment branch action time length, and the second preset time length is determined as the two-segment branch action time length.

[0150] According to example embodiments, the second preset time length is greater than the first preset time length, and the difference between the second preset time length and the first preset time length is the first preset delay time length.

[0151] According to example embodiments, the first preset time length can be specifically 0s. The first preset delay time length can be specifically any value in 0.1s-0.6s, and the value of the first preset delay time length can be set by the user as needed.

[0152] According to an example embodiment, in the case that there is no branch sub-grid in the branch grid, such as the branch grid corresponding to the user interface switch 6 shown in FIG. 2 and FIG. 7, the protection mechanism of the boundary switch corresponding to the branch grid does not need to cooperate with other boundary switches, and thus the electronic device can directly set the one-segment branch action duration to 0s and the two-segment branch action duration to a value equal to the first preset delay duration, such as 0.2s.

[0153] In the case that there is a branch sub-grid in the branch grid, the electronic device determines the one-segment branch action duration and the two-segment branch action duration of the boundary switch of the branch grid, which can include step S142b.

[0154] In step S142b, the one-segment maximum sub-action duration and the two-segment maximum sub-action duration are determined according to the first protection configuration information, and the second preset delay duration is added to the one-segment maximum sub-action duration to obtain the one-segment branch action duration, and the third preset delay duration is added to the two-segment maximum sub-action duration to obtain the two-segment branch action duration.

[0155] According to an example embodiment, in the case that there is a branch sub-grid in the branch grid, such as the branch grid corresponding to the branch switch 2 or the branch switch 3 shown in FIG. 2 and FIG. 7, the protection mechanism of the boundary switch corresponding to the branch grid needs to cooperate with the boundary switches of the branch sub-grid.

[0156] According to an example embodiment, the one-segment maximum sub-action duration is the maximum duration in the one-segment action durations corresponding to the branch sub-grid, and the two-segment maximum sub-action duration is the maximum duration in the two-segment action durations corresponding to the branch sub-grid. For example, referring to FIG. 2 and FIG. 7, in the branch grid corresponding to the branch switch 3, the branch sub-grid includes the load grid corresponding to the user interface switch 5 and the branch grid corresponding to the distributed power supply, and the one-segment maximum sub-action duration is the maximum value of the one-segment load action duration of the user interface switch 5 and the one-segment branch action duration of the user interface switch 6, and the two-segment maximum sub-action duration is the maximum value of the two-segment branch action duration of the user interface switch 5 and the two-segment branch action duration of the user interface switch 6.

[0157] According to an example embodiment, in step S142b, the electronic device adds the second preset delay duration to the one-segment maximum sub-action duration to obtain the one-segment branch action duration, and adds the third preset delay duration to the two-segment maximum sub-action duration to obtain the two-segment branch action duration.

[0158] The electronic device can determine the branch protection action duration of the boundary switch of the branch grid according to step S141, step S142a, and step S142b. Then, the electronic device can determine the two-section overcurrent protection mechanism configured by the boundary switch of the branch grid according to the branch protection action duration in step S150. Referring to FIG. 8, step S150 can specifically include step S151, step S152a, and step S152b.

[0159] In step S151, it is determined whether there is a large-capacity distributed power source in the power distribution network region corresponding to the branch grid.

[0160] According to some embodiments, the manner in which the electronic device determines whether there is a large-capacity distributed power source in step S151 can specifically include determining whether the upstream minimum short-circuit current is less than the downstream maximum short-circuit current. The upstream minimum short-circuit current is the minimum short-circuit current provided by all power sources in the upstream region of the boundary switch when a fault occurs in the downstream region of the boundary switch. The downstream maximum short-circuit current is the maximum short-circuit current provided by all distributed power sources in the downstream region of the boundary switch when a fault occurs in the upstream region of the boundary switch.

[0161] The electronic device can determine that there is a large-capacity distributed power source downstream of the boundary switch when it is determined that the upstream minimum short-circuit current is less than the downstream maximum short-circuit current.

[0162] In the case where there is a large-capacity distributed power source in the power distribution network region corresponding to the branch grid, the manner in which the electronic device determines the protection mechanism of the boundary switch corresponding to the branch grid includes step S152a.

[0163] In step S152a, in the case where there is a large-capacity distributed power source in the power distribution network region corresponding to the branch grid, the two-section directional overcurrent protection mechanism of the boundary switch of the branch grid is determined according to the branch protection action duration.

[0164] In the case where there is no large-capacity distributed power source in the power distribution network region corresponding to the branch grid, the manner in which the electronic device determines the protection mechanism of the boundary switch corresponding to the branch grid includes step S152b.

[0165] In step S152b, in the case where there is no large-capacity distributed power source in the power distribution network region corresponding to the branch grid, the two-section overcurrent protection mechanism of the boundary switch of the branch grid is determined according to the branch protection action duration.

[0166] By executing step S151, step S152a and step S152b by the electronic device, in the case that there is a large-capacity distributed power supply in the distribution network area of the branch grid, two-section directional overcurrent protection can be configured at the boundary switch of the branch grid, so as to avoid the problem of protection misoperation caused by the large-capacity distributed power supply in the case of short-circuit fault.

[0167] According to some embodiments, referring to FIG. 9, in step S160, the electronic device determines the main line protection action time length of the boundary switch of the main line grid according to the second protection configuration information in the distribution network area corresponding to the main line grid, which can include step S161, step S162a and step S162b.

[0168] In step S161, it is determined whether there is a main line subordinate grid in the distribution network area corresponding to the main line grid.

[0169] According to example embodiments, the main line subordinate grid includes a load grid and a branch grid.

[0170] According to example embodiments, in step S161, the electronic device determines whether there is a load grid and whether there is a branch grid in the distribution network area corresponding to the main line grid.

[0171] In the case that there is no load grid and no branch grid in the main line grid, the protection mechanism of the boundary switch of the main line grid can not be matched with other boundary switches. Therefore, in this case, the electronic device can determine the manner of the main line action time length of the main line grid, which can specifically include step S162a.

[0172] In step S162a, the main line action time length of the boundary switch of the main line grid is determined to be 0. That is, the electronic device determines the main line action time length to be 0, that is, no delay directional longitudinal protection is configured at the boundary switch of the main line grid.

[0173] In the case that there is a load grid and / or there is a branch grid in the main line grid, the protection mechanism of the boundary switch of the main line grid needs to be matched with the main line subordinate grid. Therefore, in this case, the electronic device can determine the main line action time length of the main line grid, which can specifically include step S162b.

[0174] In step S162b, according to the second protection configuration information, a maximum action time length is determined from the respective protection action time lengths of the main line subordinate grids; and a fourth preset delay time length is superimposed on the basis of the maximum action time length, to obtain the main line protection action time length of the boundary switch of the main line grid.

[0175] Exemplarily, referring to FIG. 2 and FIG. 7, for the main line grid 1 (the main line grid between the substation outgoing line switch and the sectionalizing switch 1), the main line grid 1 has a main line subordinate grid, which is the load grid corresponding to the user boundary switch 1. The electronic device determines the one-section load action time corresponding to the user boundary switch 1 as the one-section maximum action time. The one-section load action time corresponding to the user boundary switch 1 is 0, and thus the one-section maximum action time is 0.

[0176] The main line protection action time of the boundary switch of the main line grid can be obtained by superimposing the fourth preset delay time on the basis of the one-section maximum action time. Exemplarily, the fourth preset delay time is 0.3 s, and thus the main line protection action time corresponding to the main line grid between the substation outgoing line switch and the sectionalizing switch 1 is 0+0.3=0.3 s.

[0177] For example, referring to FIG. 2 and FIG. 7, for the main line grid between the sectionalizing switch 1 and the tie switch, the one-section maximum action time in the main line subordinate grid of the main line grid is the one-section branch action time of the branch switch 2 or the branch switch 3. The one-section branch action time of the branch switch 2 and the branch switch 3 is determined in the manner described in the above embodiment, and is the second preset delay time. The main line protection action time of the main line grid is the second preset delay time+the fourth preset delay time.

[0178] According to some embodiments, for the boundary switch of the main line grid, the directional pilot protection is set as the main protection. In the embodiments of the present application, for the substation outgoing line switch, a two-section overcurrent protection is further configured on the substation outgoing line switch as a backup protection.

[0179] The outgoing line protection action time of the two-section overcurrent protection needs to be coordinated with the protection action time of each downstream grid of the substation outgoing line switch, so that the substation outgoing line switch can act to remove the fault in the case that the fault occurs and none of the other downstream grids acts.

[0180] According to some embodiments, referring to FIG. 10, the method can further include step S180 and step S190.

[0181] In step S180, the outgoing line protection action time of the substation outgoing line switch in the power distribution network line is determined according to the protection action time of each boundary switch in the power distribution network line.

[0182] According to the example embodiments, the substation outgoing line switch is located at the outlet of the substation, and the entire power distribution network line connected to the substation outgoing line switch is the downstream area of the substation outgoing line switch. Each main line grid, branch line grid and load grid in the power distribution network line is the downstream grid of the substation outgoing line switch.

[0183] The protection action time length of the boundary switch of each downstream grid is the protection action time length of each boundary switch in the power distribution network line.

[0184] The electronic device can determine the outgoing line protection action time length of the substation outgoing line switch according to the protection action time length of each boundary switch, so as to match the protection mechanism of each boundary switch in the power distribution network.

[0185] In step S190, the two-section overcurrent protection mechanism of the substation outgoing line switch is determined according to the outgoing line protection action time length.

[0186] According to an example embodiment, in step S190, the electronic device can determine the two-section overcurrent protection mechanism of the substation outgoing line switch according to the outgoing line protection action time length, so as to configure the two-section overcurrent protection as backup protection on the substation outgoing line switch.

[0187] According to some embodiments, the outgoing line protection action time length includes a first outgoing line protection time length and a second outgoing line protection time length. The first outgoing line protection time length is the protection action time length corresponding to the I section of the overcurrent protection of the substation outgoing line switch. The second outgoing line protection time length is the protection action time length corresponding to the II section of the overcurrent protection of the substation outgoing line switch.

[0188] Referring to FIG. 11, in step S180, the outgoing line protection action time length of the substation outgoing line switch in the power distribution network line is determined according to the protection action time length of each boundary switch in the power distribution network line, which can specifically include steps S181, S182 and S183.

[0189] In step S181, the maximum one-section time length is determined as the maximum one-section time length from among the first branch line action time length, the first load action time length and the main line protection action time length.

[0190] According to an example embodiment, in step S181, the electronic device determines the maximum time length from among the first load action time length of each load grid, the first branch line action time length of each branch line grid and the main line protection action time length of each main line grid, and the maximum time length is the maximum one-section time length.

[0191] For example, in the power distribution network line shown in FIG. 2 and FIG. 7, the maximum time length among the first load action time length of each load grid, the first branch line action time length of each branch line grid and the main line protection action time length of each main line grid is the main line protection action time length of the sectionalizing switch 1 and the tie switch.

[0192] In step S182, the first preset delay time length is superimposed on the maximum one-section time length to determine the first outgoing line protection time length of the substation outgoing line switch.

[0193] In step S183, a sixth preset delay time length is superimposed on the basis of the first section outgoing line protection time length to determine the second section outgoing line protection time length of the substation outgoing line switch.

[0194] Exemplarily, in the distribution network line as shown in FIG. 2 and FIG. 7, the maximum first section time length is the main line protection action time length of the sectionalizing switch 1 and the tie switch. In step S182, the electronic device superimposes a fifth preset delay time length on the main line protection action time length of the sectionalizing switch 1 and the tie switch to determine the first section outgoing line protection time length of the substation outgoing line switch. Then in step S183, the electronic device superimposes a sixth preset delay time length on the basis of the first section outgoing line protection time length to determine the second section outgoing line protection time length of the substation outgoing line switch.

[0195] For example, referring to FIG. 7, in the case where the first preset delay time length, the second preset delay time length, the third preset delay time length, the fourth preset delay time length, the fifth preset delay time length and the sixth preset delay time length are all T, the main line protection action time length of the sectionalizing switch 1 and the tie switch is 2T, the first section outgoing line protection time length is 3T, and the second section outgoing line protection time length is 4T.

[0196] Those skilled in the art can understand that all or part of the steps of the above embodiments are implemented as a computer program executed by a CPU. When the computer program is executed by the CPU, the above functions defined by the above method provided by the present application are executed.

[0197] The above embodiments introduce a method for grid protection configuration of a distribution network from the perspective of method flow. The following embodiments introduce a device for grid protection of a distribution network from the perspective of virtual module or virtual unit. For details, please refer to the following embodiments.

[0198] The device embodiments of the present application described below can be used to execute the method embodiments of the present application. For details not disclosed in the device embodiments of the present application, please refer to the method embodiments of the present application.

[0199] As shown in FIG. 12, a device for grid protection of a distribution network includes a boundary switch determination module 1201, a grid division module 1202, a load mechanism determination module 1203, a branch line protection time length determination module 1204, a branch line mechanism determination module 1205, a main line protection time length determination module 1206 and a main line mechanism determination module 1207.

[0200] The boundary switch determination module 1201 is configured to determine boundary switches from each switch of the power distribution network line. The grid division module 1202 is configured to divide the power distribution network line according to the boundary switches to determine a load grid, a branch line grid and a main line grid. The load mechanism determination module 1203 is configured to determine a two-section overcurrent protection mechanism of the boundary switches in the load grid according to a preset load grid rule. The branch line protection time determination module 1204 is configured to determine a branch line protection action time of the boundary switches of the branch line grid according to first protection configuration information in a power distribution network region corresponding to the branch line grid. The branch line mechanism determination module 1205 is configured to determine a two-section overcurrent protection mechanism of the boundary switches of the branch line grid according to the branch line protection action time. The main line protection time determination module 1206 is configured to determine a main line protection action time of the boundary switches of the main line grid according to second protection configuration information in a power distribution network region corresponding to the main line grid. The main line mechanism determination module 1207 is configured to determine a directional pilot protection mechanism of the boundary switches of the main line grid according to the main line protection action time.

[0201] The first protection configuration information is information of protection mechanisms of the boundary switches in the power distribution network region corresponding to the branch line grid which have determined protection mechanisms. The second protection configuration information is information of protection mechanisms of the boundary switches in the power distribution network region corresponding to the main line grid which have determined protection mechanisms.

[0202] The apparatus performs similar functions to the method provided above, and other functions can be referred to the foregoing description, which will not be described here.

[0203] Embodiments of the present application also introduce an electronic device from the perspective of a physical device. Referring to FIG. 13, the electronic device 1300 shown in FIG. 13 includes a processor 1301 and a memory 1303. The processor 1301 and the memory 1303 are connected, for example, through a bus 1302. Optionally, the electronic device 1300 can also include a transceiver 1304. In actual applications, the transceiver 1304 is not limited to one, and the structure of the electronic device 1300 does not constitute a limitation on the embodiments of the present application.

[0204] The processor 1301 can be a Central Processing Unit (CPU), a general-purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, a transistor logic device, a hardware component, or any combination thereof. It can implement or execute the various exemplary logical blocks, modules and circuits described in connection with the disclosure. The processor 1301 can also be a combination of computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, and the like.

[0205] The bus 1302 can include a path that carries information between the aforementioned components. The bus 1302 can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, or the like. The bus 1302 can be divided into an address bus, a data bus, a control bus, and the like. For ease of representation, only one thick line is shown in FIG. 13, but it does not mean that there is only one bus or only one type of bus.

[0206] The memory 1303 can be a Read Only Memory (ROM) or other type of static storage device that can store static information and instructions, a Random Access Memory (RAM) or other type of dynamic storage device that can store information and instructions, an Electrically Erasable Programmable Read Only Memory (EEPROM), a Compact Disc Read Only Memory (CD-ROM) or other optical disk storage, a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer.

[0207] The memory 1303 is configured to store application program codes for implementing the solutions of the present application, and the processor 1301 is configured to control the execution of the application program codes. The processor 1301 is configured to execute the application program codes stored in the memory 1303 to implement the content shown in the foregoing method embodiments.

[0208] The electronic device includes a mobile terminal such as a mobile phone, a notebook computer, a digital broadcast receiver, a personal digital assistant (PDA), a tablet computer (PAD), a portable multimedia player (PMP), a car terminal (e.g., a car navigation terminal), and the like, and a stationary terminal such as a digital TV, a desktop computer, and the like, and can also be a server or the like. The electronic device shown in FIG. 13 is one example.

[0209] The embodiments of the present application provide a computer readable storage medium, which stores a computer program. When the computer program is run on a computer, the computer can execute the corresponding content in the foregoing method embodiments. The storage medium can be a read-only memory, a disk or an optical disk, etc.

[0210] The embodiments of the present application also provide a computer program product. The computer program product includes a computer program stored on a computer readable storage medium, and the computer program includes program instructions. When the program instructions are executed by a computer, the computer executes the corresponding content in the above method embodiments.

Claims

1. A power distribution network mesh protection method, the method comprising: determining boundary switches from each switch of a power distribution network line; dividing the power distribution network line according to the boundary switches to determine a load mesh, a branch mesh and a main line mesh; determining a two-section overcurrent protection mechanism of the boundary switches in the load mesh according to preset load mesh rules; determining a branch protection action duration of the boundary switches of the branch mesh according to first protection configuration information in a power distribution network region corresponding to the branch mesh; determining a two-section overcurrent protection mechanism of the boundary switches of the branch mesh according to the branch protection action duration; determining a main line protection action duration of the boundary switches of the main line mesh according to second protection configuration information in a power distribution network region corresponding to the main line mesh; determining a directional pilot protection mechanism of the boundary switches of the main line mesh according to the main line protection action duration; wherein the first protection configuration information is information of protection mechanisms of the boundary switches in the power distribution network region corresponding to the branch mesh which have already been determined; the second protection configuration information is information of protection mechanisms of the boundary switches in the power distribution network region corresponding to the main line mesh which have already been determined.

2. The method of claim 1, wherein, The boundary switches comprise main line boundary switches, branch boundary switches and load boundary switches, The determining of the boundary switches from each switch of the power distribution network line comprises: determining the main line boundary switches according to main line switches on a main line of the power distribution network line; determining the branch boundary switches according to branch switches on a branch of the power distribution network line and interface switches connected to a distributed power supply, the branch switches being switches controlling connection between the branch and the main line; determining the load boundary switches according to each load switch connected to a load in the power distribution network line.

3. The method of claim 2, wherein, The determining of the main line boundary switches according to the main line switches on the main line of the power distribution network line comprises: starting from a substation outgoing line switch, sequentially determining, from each main line switch along the main line of the power distribution network line, a main line switch meeting a preset threshold condition as a main line boundary switch; wherein the preset threshold condition is that total load capacity of a power distribution line section between two adjacent main line boundary switches exceeds a preset load capacity value or the number of branches connected in the power distribution line section is not less than a preset branch number.

4. The method of claim 2, wherein, The determining of the branch boundary switches according to the branch switches on the branch of the power distribution network line and the interface switches connected to the distributed power supply comprises: determining a target branch from each branch, wherein the target branch is a branch in which there are at least two main line switches on a main line section between a substation bus; determining the branch switches in the target branch and the interface switches connected to the distributed power supply as branch boundary switches.

5. The method of claim 1, wherein, The dividing of the power distribution network line according to the boundary switches to determine the load mesh, the branch mesh and the main line mesh comprises: From the boundary switches, a first boundary switch is determined, the first boundary switch is a boundary switch without other boundary switches in a downstream power distribution network region and without a large-capacity distributed power supply in the downstream power distribution network region; The first boundary switch and the downstream power distribution network region of the first boundary switch are divided into a load grid; From the boundary switches, a second boundary switch is determined, the second boundary switch is a boundary switch satisfying a preset division condition; The second boundary switch and the downstream power distribution network region of the second boundary switch are divided into a branch line grid; From the boundary switches, a third boundary switch is determined, the third boundary switch is a boundary switch located on a main line; A power distribution network region between two adjacent third boundary switches in the power distribution network is divided into a main line grid; The preset division condition includes a first preset division condition and a second preset division condition; The first preset division condition is that the boundary switch is located on a non-main line in the power distribution network line, and there is a load grid in the downstream power distribution network region of the boundary switch; The second preset division condition is that the boundary switch is located on a non-main line in the power distribution network line, and there is a large-capacity distributed power supply in the downstream power distribution network region of the boundary switch.

6. The method of claim 1 or 5, wherein, The branch line protection action time length includes a first branch line action time length and a second branch line action time length; The branch line protection action time length of the branch line boundary switch is determined according to the first protection configuration information in the power distribution network region corresponding to the branch line grid, including: It is judged whether there is a branch line subordinate grid in the branch line grid, the branch line subordinate grid is other grid contained in the power distribution network region corresponding to the branch line grid; If not, including: A first preset time length is determined as the first branch line action time length; and A second preset time length is determined as the second branch line action time length, wherein the second preset time length is greater than the first preset time length, and the difference between the second preset time length and the first preset time length is a first preset delay time length; If yes, including: According to the first protection configuration information, a first maximum subordinate action time length and a second maximum subordinate action time length are determined, the first maximum subordinate action time length is the maximum time length in the first action time length corresponding to the branch line subordinate grid, and the second maximum subordinate action time length is the maximum time length in the second action time length corresponding to the branch line subordinate grid; and A second preset delay time length is superimposed on the basis of the first maximum subordinate action time length to obtain the first branch line action time length; A third preset delay time length is superimposed on the basis of the second maximum subordinate action time length to obtain the second branch line action time length.

7. The method of claim 1, wherein, The two-section overcurrent protection mechanisms of the boundary switch of the branch line grid are determined according to the branch line protection action time length, including: It is judged whether there is a large-capacity distributed power supply in the power distribution network region corresponding to the branch line grid; If yes, the two-section directional overcurrent protection mechanisms of the boundary switch of the branch line grid are determined according to the branch line protection action time length; If not, the two-section overcurrent protection mechanisms of the boundary switch of the branch line grid are determined according to the branch line protection action time length.

8. The method of claim 1, wherein, The main line protection action time length of the boundary switch of the main line grid is determined according to second protection configuration information in a power distribution network region corresponding to the main line grid, and the method comprises the following steps: It is judged whether there is a main line sub-grid in the power distribution network region corresponding to the main line grid, and the main line sub-grid comprises a load grid and a branch line grid; If not, the main line action time length of the boundary switch of the main line grid is determined to be 0; If yes, the method comprises the following steps: According to the second protection configuration information, a maximum action time length is determined from the protection action time lengths corresponding to the main line sub-grids respectively; and A fourth preset delay time length is superimposed on the basis of the maximum action time length, so as to obtain the main line protection action time length of the boundary switch of the main line grid.

9. The method according to claim 1, further comprising: According to the protection action time lengths of the boundary switches in the power distribution network line, the outgoing line protection action time length of the outgoing line switch of the transformer substation in the power distribution network line is determined; According to the outgoing line protection action time length, the two-section over-current protection mechanisms of the outgoing line switch of the transformer substation are determined.

10. The method of claim 9, wherein, The load protection action time length corresponding to the boundary switch of each load grid comprises a first load action time length and a second load action time length; The branch line protection action time length corresponding to the boundary switch of each branch line grid comprises a first branch line action time length and a second branch line action time length; The outgoing line protection action time length comprises a first outgoing line protection time length and a second outgoing line protection time length; The outgoing line protection action time length of the outgoing line switch of the transformer substation in the power distribution network line is determined according to the protection action time lengths of the boundary switches in the power distribution network line, and the method comprises the following steps: The maximum one-section time length is determined by taking the maximum time length among the first branch line action time length, the first load action time length and the main line protection action time length; The fifth preset delay time length is superimposed on the basis of the maximum one-section time length, so as to determine the first outgoing line protection time length of the outgoing line switch of the transformer substation; The sixth preset delay time length is superimposed on the basis of the first outgoing line protection time length, so as to determine the second outgoing line protection time length of the outgoing line switch of the transformer substation.

11. A power distribution network grid protection device, comprising: A boundary switch determination module is arranged to determine the boundary switches from the switches in the power distribution network line; A grid division module is arranged to divide the power distribution network line according to the boundary switches, so as to determine the load grid, the branch line grid and the main line grid; A load mechanism determination module is arranged to determine the two-section over-current protection mechanisms of the boundary switches in the load grid according to preset load grid rules; A branch line protection time length determination module is arranged to determine the branch line protection action time length of the boundary switch of the branch line grid according to first protection configuration information in a power distribution network region corresponding to the branch line grid; A branch line mechanism determination module is arranged to determine the two-section over-current protection mechanisms of the boundary switches of the branch line grid according to the branch line protection action time length; A main line protection time length determination module is arranged to determine the main line protection action time length of the boundary switch of the main line grid according to second protection configuration information in a power distribution network region corresponding to the main line grid. The main line mechanism determination module is configured to determine a directional pilot protection mechanism of the boundary switch of the main line grid according to the main line protection action time length; The first protection configuration information is information of a protection mechanism of a boundary switch in a power distribution grid area corresponding to the branch line grid, for which the protection mechanism has been determined; The second protection configuration information is information of a protection mechanism of a boundary switch in a power distribution grid area corresponding to the main line grid, for which the protection mechanism has been determined. 12.An electronic device, comprising: one or more processors; a storage device for storing one or more programs; when the one or more programs are executed by the one or more processors, the one or more processors implement the method of any one of claims 1-10. 13.A computer readable medium having stored thereon a computer program, the program being executed by a processor to implement the method of any one of claims 1-10. 14.A computer program product comprising a computer program stored on a computer readable storage medium, the computer program comprising program instructions that when executed by a computer cause the computer to perform the method of any one of claims 1-10.

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