Feeder automatic short-circuit fault interval detection method and system

Abstract

The present invention discloses a method and system for detecting short-circuit fault intervals in feeder automation. When a short-circuit fault occurs in a line, the substation outgoing line circuit breaker trips due to overcurrent protection. The switch at this level selects to exchange data with any switch at the next level based on the overcurrent signal detected by itself, and determines the fault interval based on the data interaction. The first switch determines the fault interval based on the overcurrent signal detected by itself, thus solving the problem that existing slow-acting distributed feeder automation lines cannot locate faults between the substation outgoing line circuit breaker and the first switch. Compared with existing slow-acting distributed feeder automation, the present invention has higher data exchange efficiency between switches, simpler fault interval location logic, and faster fault interval location. It is particularly suitable for the construction and renovation of feeder automation lines using wireless communication.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid line fault detection, and in particular to a feeder automation short-circuit fault interval detection method and system. Background Art

[0002] At present, distributed feeder automation mostly adopts slow-acting distributed feeder automation in 10kV overhead lines of distribution networks. Fast-acting distributed feeder automation has not been widely used due to the high cost of optical fiber investment and the difficulty of operation and maintenance. After a short circuit fault occurs in the slow-acting distributed feeder automation, the fault location, isolation and automatic power supply restoration of the feeder are achieved through communication between distribution terminals. The distribution terminals report the processing process and results to the distribution automation master station.

[0003] Distribution terminals under slow-acting distributed feeder automation mostly use wireless communication to achieve information exchange between distribution terminals and between distribution terminals and distribution master stations. Substation outgoing circuit breakers mostly use dedicated optical fibers to communicate with the dispatching automation master station. However, substation outgoing circuit breakers and the first switch in the line are usually unable to communicate. Therefore, the slow-acting distributed feeder automation line cannot locate the fault between the substation outgoing circuit breaker and the first switch.

[0004] In view of this, when the first switch cannot communicate with the substation outgoing circuit breaker, the existing slow-acting distributed feeder automation line cannot locate the fault between the substation outgoing circuit breaker and the first switch. It is necessary to improve the method for determining the short-circuit fault interval of the existing slow-acting distributed feeder automation line to enhance the adaptability of the fault handling method. Summary of the Invention

[0005] The present invention provides a feeder automation short-circuit fault interval detection method and system. When a short-circuit fault occurs in a line, the substation outlet circuit breaker trips due to overcurrent protection. The switch at this level selects to exchange data with any level switch based on the overcurrent signal detected by itself, and determines the fault interval based on the data interaction. The first switch determines the fault interval based on the overcurrent signal detected by itself, thereby solving the problem that the existing slow-acting distributed feeder automation line cannot locate the fault between the substation outlet circuit breaker and the first switch, and solving the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a feeder automation short-circuit fault interval detection method, comprising the following steps: after the outgoing circuit breaker of the substation trips, the switch at this level selects to perform data exchange and fault interval location with any switch at the next level according to the overcurrent signal detected by itself;

[0008] The first switch determines the fault section based on the overcurrent signal detected by itself.

[0009] Preferably, when the first switch detects an overcurrent signal, it determines the overcurrent signal status of the switch at this stage;

[0010] When the primary switch does not detect an overcurrent signal and the communication with the substation outgoing line circuit breaker is normal, the overcurrent signal condition of the switch at this level is determined;

[0011] When the first switch does not detect an overcurrent signal and cannot communicate with the substation outgoing circuit breaker, the first switch remains in the closed state and waits for the substation outgoing circuit breaker to reclose. The fault interval is determined based on the voltage signal on the power supply side of the first switch after the substation outgoing circuit breaker is reclosed for the first time.

[0012] Preferably, the switch at this level detects an overcurrent signal and inquires about the situation of the switch at the next level detecting an overcurrent signal;

[0013] If the switch at this level does not detect an overcurrent signal, it will inquire about whether the switch at the previous level detects an overcurrent signal.

[0014] Preferably, when the next-stage switch detects an overcurrent signal, it is determined that the fault point is not between the current-stage switch and the next-stage switch;

[0015] When the next-stage switch does not detect an overcurrent signal, it is determined that the fault point is between the current-stage switch and the next-stage switch.

[0016] Preferably, when the upper-level switch detects an overcurrent signal, it is determined that the fault point is between the current-level switch and the upper-level switch;

[0017] When the upper-level switch does not detect an overcurrent signal, it is determined that the fault point is not between the current-level switch and the upper-level switch.

[0018] Preferably, when the voltage signal is detected on the power supply side of the first switch, the fault interval is determined according to the change of the voltage signal within the set time X time limit.

[0019] Preferably, if the voltage signal disappears within the set time X time limit, it is judged that the fault section is between the substation outgoing line circuit breaker and the first switch; if the voltage signal does not disappear within the set time X time limit, it is judged that the fault section is not between the substation outgoing line circuit breaker and the first switch.

[0020] Preferably, the calculation of the single reclosing time T of the substation outgoing circuit breaker includes: calculating the maximum time T1 of the line automation switch opening, calculating the communication time T2 for data interaction between switches, and calculating the redundancy time T3, then T=T1+T2+T3.

[0021] The present invention provides a feeder automation short-circuit fault interval detection system, comprising: a first unit, after the substation outgoing line circuit breaker trips, the switch at this level selects to exchange data and locate the fault interval with any switch at the next level according to the overcurrent signal detected by itself; a second unit, the first switch determines the fault interval according to the overcurrent signal detected by itself.

[0022] The beneficial effects of the present invention are:

[0023] 1. Compared with the existing slow-acting distributed feeder automation, the present invention determines the overcurrent signal of the switch at this level by detecting the overcurrent signal of the first switch, so that the switch at this level can exchange data with the switch at any level, and judge the fault range based on the data interaction. This solves the problem of locating the fault between the substation outgoing circuit breaker and the first switch when the first switch cannot communicate with the substation outgoing circuit breaker.

[0024] 2. The data exchange efficiency between the first switch, the current-level switch and any-level switch is higher, the fault interval positioning logic is simpler, and the fault interval positioning is faster. It is particularly suitable for the construction and transformation of feeder automation lines using wireless communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a working principle diagram of a feeder automatic short-circuit fault interval detection method of the present invention;

[0026] Figure 2 Another working principle diagram of a feeder automatic short-circuit fault interval detection method of the present invention;

[0027] Figure 3 This is a step diagram of a method for automatically detecting a short-circuit fault interval of a feeder according to the first embodiment of the present invention;

[0028] Figure 4 This is a step diagram of a method for automatically detecting short-circuit fault intervals in feeders according to a second embodiment of the present invention;

[0029] Figure 5 This is a schematic diagram of a feeder automatic short-circuit fault interval detection system of the present invention. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0031] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0032] It should also be understood that the terms used in the present specification are only for the purpose of describing particular embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0033] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0034] The present invention provides Figure 5 A feeder automatic short-circuit fault interval detection system is shown, comprising:

[0035] The first unit 11, after the substation outgoing line circuit breaker trips, the switch at this level chooses to exchange data and locate the fault section with any level switch according to the overcurrent signal detected by itself; the second unit 12, the first switch determines the fault section according to the overcurrent signal detected by itself.

[0036] Example 1:

[0037] The present invention provides a feeder automatic short circuit fault interval detection method, combined with Figure 3 To further describe, the following steps are included:

[0038] Step S101: After the outgoing circuit breaker of the substation trips, the switch at this level selects any switch at the next level to exchange data and locate the fault area based on the overcurrent signal detected by itself.

[0039] Step S102: After the outgoing circuit breaker of the substation trips, the primary switch determines the fault zone based on the overcurrent signal detected by itself;

[0040] Step S103: When the first switch detects an overcurrent signal, the overcurrent signal status of the switch at this level is determined; when the first switch does not detect an overcurrent signal and the communication with the substation outgoing line circuit breaker is normal, the overcurrent signal status of the switch at this level is determined; when the switch at this level detects an overcurrent signal, the status of the overcurrent signal detected by the switch at the next level is inquired; when the switch at this level does not detect an overcurrent signal, the status of the overcurrent signal detected by the switch at the previous level is inquired;

[0041] In step S104, when the next-level switch detects an overcurrent signal, it is determined that the fault point is not between the switch at this level and the switch at the next level, and the switch at this level maintains the switch closed position unchanged; when the next-level switch does not detect an overcurrent signal, it is determined that the fault point is between the switch at this level and the switch at the next level, and the switch at this level automatically opens and locks the switch closed; when the previous-level switch detects an overcurrent signal, it is determined that the fault point is between the switch at this level and the switch at the previous level, and the switch at this level automatically opens and locks the switch closed; when the previous-level switch does not detect an overcurrent signal, it is determined that the fault point is not between the switch at this level and the switch at the previous level, and the switch at this level maintains the switch closed position unchanged.

[0042] In step S105, when the first switch does not detect an overcurrent signal and cannot communicate with the substation outgoing circuit breaker, the first switch remains in the closed state and waits for the substation outgoing circuit breaker to reclose. The fault interval is determined based on the voltage signal on the power supply side of the first switch after the substation outgoing circuit breaker is reclosed for the first time.

[0043] In step S106, when a voltage signal is detected on the power supply side of the primary switch, the fault section is determined based on the change in the voltage signal within the set time X time limit. If the voltage signal disappears within the set time X time limit, the fault section is determined to be between the substation outgoing circuit breaker and the primary switch, and the primary switch automatically opens. If the voltage signal does not disappear within the set time X time limit, the fault section is determined not to be between the substation outgoing circuit breaker and the primary switch, and the primary switch remains in the closed position.

[0044] Example 2:

[0045] The present invention provides a feeder automatic short circuit fault interval detection method, combined with Figure 4 The following further describes the calculation of the time for one reclosing of the outgoing circuit breaker of the substation, including the following steps:

[0046] Step S201, calculating the maximum opening time T1 of the line automation switch;

[0047] Step S202, calculating the data exchange communication time T2 between switches;

[0048] Step S203, ensuring that before the outgoing circuit breaker in the substation is reclosed once, the line automation switch completes the line fault processing according to a feeder automation short-circuit fault interval detection method, and calculating the redundancy time T3;

[0049] Step S204: Calculate the primary reclosing time parameter T=T1+T2+T3 of the outgoing circuit breaker of the substation.

[0050] In the present invention, the distribution automation switch can be a load switch or a circuit breaker, and the distribution automation switches can communicate with each other using a wireless network or optical fiber communication method. The communication protocol can adopt the DL / T634.5101-2002 balanced protocol or the DL / T634.5104-2002 protocol.

[0051] In the present invention, unless otherwise clearly specified and limited, the "previous level" and "next level" in the characteristics that represent the order of switches refer to when the line is normally powered, from the substation outgoing circuit breaker to the various automatic switches in the line, the switch through which the current flows first is the previous level switch, and the switch through which the current flows later is the next level switch.

[0052] In the present invention, unless otherwise specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed or detachable connections, or integration; mechanical or electrical connections, or communication; direct or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention.

Claims

1. A method for detecting feeder line short-circuit fault interval automatically, characterized in that: The following steps are involved: After the outgoing circuit breaker of the substation trips, the switch at this level will choose to exchange data and locate the fault area with any switch at the next level based on the overcurrent signal detected by itself. The first switch determines the fault range based on the overcurrent signal detected by itself; When the first switch detects an overcurrent signal, it determines the overcurrent signal status of the switch at this stage; When the primary switch does not detect an overcurrent signal and the communication with the substation outgoing line circuit breaker is normal, the overcurrent signal condition of the switch at this level is determined; When the primary switch does not detect an overcurrent signal and cannot communicate with the substation outgoing circuit breaker, the primary switch remains in the closed state and waits for the substation outgoing circuit breaker to reclose. The fault interval is determined based on the voltage signal on the power supply side of the primary switch after the substation outgoing circuit breaker is reclosed for the first time. When the switch at this level detects an overcurrent signal, it will inquire about the situation of the switch at the next level detecting an overcurrent signal; If the switch at this level does not detect an overcurrent signal, it will inquire about the situation where the switch at the previous level detects an overcurrent signal; When the next-stage switch detects an overcurrent signal, it determines that the fault point is not between the current-stage switch and the next-stage switch; When the next-stage switch does not detect an overcurrent signal, it is determined that the fault point is between the current-stage switch and the next-stage switch; When the upper switch detects an overcurrent signal, it is determined that the fault point is between the switch at this level and the switch at the upper level; When the upper-level switch does not detect an overcurrent signal, it is determined that the fault point is not between the current-level switch and the upper-level switch; When the voltage signal is detected on the power supply side of the first switch, the fault interval is determined according to the change of the voltage signal within the set time X time limit.

2. A feeder automation short-circuit fault interval detection method according to claim 1, characterized in that: If the voltage signal disappears within the set time X, the fault interval is determined to be between the outgoing circuit breaker and the primary switch of the substation; If the voltage signal does not disappear within the set time X, it is determined that the fault section is not between the substation outgoing line circuit breaker and the primary switch.

3. A feeder automation short-circuit fault interval detection method according to claim 1, characterized in that: The calculation of the reclosing time T of the substation outgoing circuit breaker includes: calculating the maximum time T1 of the line automatic switch opening, calculating the communication time T2 of the data interaction between the switches, and calculating the redundancy time T3, so T=T1+T2+T3 4. A feeder automation short circuit fault interval detection system, characterized in that: include: In the first unit, after the outgoing circuit breaker of the substation trips, the switch at this level selects any switch at the next level to exchange data and locate the fault area based on the overcurrent signal detected by itself; In the second unit, the first switch determines the fault interval based on the overcurrent signal detected by itself; When the first switch detects an overcurrent signal, it determines the overcurrent signal status of the switch at this stage; When the primary switch does not detect an overcurrent signal and the communication with the substation outgoing line circuit breaker is normal, the overcurrent signal condition of the switch at this level is determined; When the primary switch does not detect an overcurrent signal and cannot communicate with the substation outgoing circuit breaker, the primary switch remains in the closed state and waits for the substation outgoing circuit breaker to reclose. The fault interval is determined based on the voltage signal on the power supply side of the primary switch after the substation outgoing circuit breaker is reclosed for the first time. When the switch at this level detects an overcurrent signal, it will inquire about the situation of the switch at the next level detecting an overcurrent signal; If the switch at this level does not detect an overcurrent signal, it will inquire about the situation where the switch at the previous level detects an overcurrent signal; When the next-stage switch detects an overcurrent signal, it determines that the fault point is not between the current-stage switch and the next-stage switch; When the next-stage switch does not detect an overcurrent signal, it is determined that the fault point is between the current-stage switch and the next-stage switch; When the upper switch detects an overcurrent signal, it is determined that the fault point is between the switch at this level and the switch at the upper level; When the upper-level switch does not detect an overcurrent signal, it is determined that the fault point is not between the current-level switch and the upper-level switch; When the voltage signal is detected on the power supply side of the first switch, the fault interval is determined according to the change of the voltage signal within the set time X time limit.

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