Export circuit for shortening non-full-phase operation time in single-phase mode of substation line

Abstract

The present invention provides an outlet circuit for shortening the non-full-phase operation time under the single-phase mode of a transformer substation line, comprising a first series circuit, a second series circuit and a third series circuit arranged in parallel; the first series circuit comprises a first set of intelligent terminal fault normally open contacts, a first parallel circuit and a starting coil of a first relay, and the first parallel circuit comprises a second set of intelligent terminal A-phase second tripping outlets, a second set of intelligent terminal B-phase second tripping outlets and a second set of intelligent terminal C-phase second tripping outlets arranged in parallel. In the present invention, when the first set of intelligent terminals fails and a single-phase grounding fault happens to occur in the line, the first fault normally open contact of the first set of intelligent terminals and the first fault normally open contact are closed, and when any phase outlet of the second set of intelligent terminals is actuated, the first relay and the second relay are activated, and the first relay and the second relay are actuated and the permanent trip relay of the second set of intelligent terminals is activated, so that the three-phase outlet of the second set of intelligent terminals is tripped.

Description

Technical Field

[0001] The invention belongs to the technical field of relay protection of electric power system, and in particular relates to an outlet circuit for shortening non-full-phase operation time in a single-phase mode of a transformer substation line. Background Art

[0002] Since the single-phase grounding fault rate of 220kV and above transmission lines is high, the single-phase reclosing method can effectively improve the power supply reliability and system stability. At present, the 220kV and above lines of smart substations are equipped with two sets of line protection, each of which includes independent protection functions and reclosing functions.

[0003] Each set of line protection is equipped with a corresponding intelligent terminal. The line protection transmits the tripping and reclosing information to the corresponding intelligent terminal (the first set of line protection corresponds to the first set of intelligent terminals; the second set of line protection corresponds to the second set of intelligent terminals), and the intelligent terminal realizes the tripping and closing of the line circuit breaker.

[0004] In order to simplify the opening and closing reclosing circuit between the two sets of line protection, some substations only use the first set of line protection reclosing function. Under normal circumstances, when there is a single-phase grounding fault in the line (such as phase A), both sets of protection can correctly select the fault phase (phase A) and trip the corresponding phase (phase A) circuit breaker of the line through the corresponding intelligent terminal; at this time, the single-phase reclosing function of the first set of line protection is started, and after the setting delay, it will act and reclose the phase A circuit breaker. If the fault has been eliminated at this time, the line will resume normal operation.

[0005] However, the above solution has the following problems:

[0006] When only the first set of line protection single-phase reclosing function is put into use, if the first set of intelligent terminals fails and a single-phase grounding fault occurs in the line, the first set of line protection can be activated, but it cannot be tripped because the first set of intelligent terminals has failed; the second set of line protection can correctly select the faulty phase and operate, and the second set of intelligent terminals can also trip; at this time, regardless of whether the first set of line protection single-phase reclosing can operate, it cannot be closed because the first set of intelligent terminals has failed. This will cause the system to operate in non-full phases until the circuit breaker's non-full phase protection operates and trips the remaining two phase switches. When the line is in non-full phase operation for a long time, the negative sequence current will generate additional losses, increase line losses and voltage drops, and may cause other protections to malfunction, threatening the safety of the power grid. Summary of the invention

[0007] The purpose of the present invention is to make up for the deficiencies of the prior art and provide an export circuit that shortens the non-full-phase operation time in a single-phase mode of a transformer substation line.

[0008] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0009] An outlet circuit for shortening non-full-phase operation time in a single-phase mode of a transformer substation line comprises a first series circuit, a second series circuit and a third series circuit arranged in parallel;

[0010] The first series circuit includes a first set of intelligent terminal first fault normally open contacts, a first parallel circuit and a starting coil of a first relay connected in series between positive electricity and negative electricity, and the first parallel circuit includes a second set of intelligent terminal A-phase second tripping outlets, a second set of intelligent terminal B-phase second tripping outlets and a second set of intelligent terminal C-phase second tripping outlets arranged in parallel;

[0011] The second series circuit includes a first set of intelligent terminal second fault normally open contacts, a second parallel circuit and a starting coil of a second relay connected in series between positive electricity and negative electricity, and the second parallel circuit includes a second set of intelligent terminal A phase third tripping outlet, a second set of intelligent terminal B phase third tripping outlet and a second set of intelligent terminal C phase third tripping outlet arranged in parallel;

[0012] The third series circuit includes a normally open output contact of a first relay connected in series between positive electricity and negative electricity, a normally open output contact of a second relay, and a second set of permanent trip relays of the intelligent terminal.

[0013] Furthermore, the condition for closing the fault normally open contacts of the first set of intelligent terminals is that a fault occurs in the first set of intelligent terminals.

[0014] Furthermore, the second tripping output of the second intelligent terminal A phase, the second tripping output of the second intelligent terminal B phase and the second tripping output of the second intelligent terminal C phase are used to start the first relay;

[0015] The second set of intelligent terminal A phase third tripping output, the second set of intelligent terminal B phase third tripping output and the second set of intelligent terminal C phase third tripping output are used to start the second relay.

[0016] Furthermore, the normally open output contact of the first relay and the normally open output contact of the second relay are actuated to start the permanent trip relay of the second set of intelligent terminals.

[0017] Furthermore, two relay circuits are used to improve redundancy.

[0018] The embodiments of the present invention bring the following beneficial effects:

[0019] The present invention adds the following circuits without changing the original tripping and closing circuit: the first fault normally open contact of the first set of intelligent terminals is connected in series with a parallel circuit consisting of the second tripping outlet of the second phase A of the second intelligent terminal, the second tripping outlet of the second phase B of the second intelligent terminal, and the second tripping outlet of the second phase C of the second intelligent terminal, and then the starting coil of the first relay is connected in series; the second fault normally open contact of the first set of intelligent terminals is connected in series with a parallel circuit consisting of the third tripping outlet of the second phase A of the second intelligent terminal, the third tripping outlet of the second phase B of the second intelligent terminal, and the third tripping outlet of the second phase C of the second intelligent terminal, and then the starting coil of the second relay is connected in series; in addition, the normally open outlet contact of the first relay and the normally open outlet contact of the second relay are used to start the permanent tripping relay of the second set of intelligent terminals. When the first set of intelligent terminals fails and a single-phase grounding fault occurs in the line, the first fault normally open contact and the second normally open contact of the first set of intelligent terminals are closed, and when any phase outlet of the second set of intelligent terminals is actuated, the first relay and the second relay are actuated and the permanent tripping relay of the second set of intelligent terminals is actuated, so as to realize the tripping of the three-phase outlet of the second set of intelligent terminals.

[0020] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0021] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The present invention provides a schematic diagram of an export circuit for shortening the non-full-phase operation time in a substation line single-phase mode according to an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] like Figure 1 As shown, an embodiment of the present invention provides an export circuit for shortening the non-full-phase operation time in a single-phase mode of a substation line, comprising a first series circuit, a second series circuit and a third series circuit arranged in parallel;

[0025] The first series circuit includes a first set of intelligent terminal first fault normally open contacts, a first parallel circuit and a starting coil of a first relay connected in series between positive electricity and negative electricity, and the first parallel circuit includes a second set of intelligent terminal A-phase second tripping outlets, a second set of intelligent terminal B-phase second tripping outlets and a second set of intelligent terminal C-phase second tripping outlets arranged in parallel;

[0026] The second series circuit includes a first set of intelligent terminal second fault normally open contacts, a second parallel circuit and a starting coil of a second relay connected in series between positive electricity and negative electricity, and the second parallel circuit includes a second set of intelligent terminal A phase third tripping outlet, a second set of intelligent terminal B phase third tripping outlet and a second set of intelligent terminal C phase third tripping outlet arranged in parallel;

[0027] The third series circuit includes a normally open output contact of a first relay connected in series between positive electricity and negative electricity, a normally open output contact of a second relay, and a second set of permanent trip relays of the intelligent terminal.

[0028] Furthermore, the condition for the first fault normally open contact and the second fault normally open contact of the first set of intelligent terminals to be closed is that a fault occurs in the first set of intelligent terminals.

[0029] Furthermore, the second tripping output of the second intelligent terminal A phase, the second tripping output of the second intelligent terminal B phase and the second tripping output of the second intelligent terminal C phase are used to start the first relay;

[0030] The second set of intelligent terminal A phase third tripping output, the second set of intelligent terminal B phase third tripping output and the second set of intelligent terminal C phase third tripping output are used to start the second relay.

[0031] Furthermore, the normally open output contact of the first relay and the normally open output contact of the second relay are actuated to start the permanent trip relay of the second set of intelligent terminals.

[0032] Furthermore, two relay circuits are used to improve redundancy and reliability.

[0033] In the present invention, under the premise of not changing the original tripping and closing circuit, the following circuit is added: the first fault normally open contact of the first set of intelligent terminals is connected in series with a parallel circuit consisting of the second tripping output of the second phase A of the second intelligent terminal, the second tripping output of the second phase B of the second intelligent terminal, and the second tripping output of the second phase C of the second intelligent terminal, and then the starting coil of the first relay is connected in series; the second fault normally open contact of the first set of intelligent terminals is connected in series with a parallel circuit consisting of the third tripping output of the second phase A of the second intelligent terminal, the third tripping output of the second phase B of the second intelligent terminal, and the third tripping output of the second phase C of the second intelligent terminal, and then the starting coil of the second relay is connected in series; in addition, the normally open output contact of the first relay and the normally open output contact of the second relay are used to start the permanent trip relay of the second set of intelligent terminals.

[0034] In this embodiment, a second relay circuit is added to start, and two relay circuits are used to improve redundancy. In addition, the starting circuit of the first relay is connected to the second tripping outlet of the second intelligent terminal ABC by the first fault outlet contact of the first intelligent terminal; the starting circuit of the second relay is connected to the third outlet of the second intelligent terminal ABC by the second fault outlet contact of the first intelligent terminal.

[0035] In this embodiment, when the first set of intelligent terminals fails and a single-phase grounding fault occurs in the line, the first fault normally open contact and the second fault normally open contact of the first set of intelligent terminals are closed, and when any phase output of the second phase A second trip output of the second set of intelligent terminals, the second phase B second trip output of the second set of intelligent terminals, and the second phase C second trip output of the second set of intelligent terminals is actuated, the first relay will be started; when any phase output of the third phase A third trip output of the second set of intelligent terminals, the third phase B third trip output of the second set of intelligent terminals, and the third phase C third trip output of the second set of intelligent terminals is actuated, the second relay will be started; the first relay and the second relay are actuated and the permanent trip relay of the second set of intelligent terminals is started, thereby realizing the tripping of the three-phase output of the second set of intelligent terminals.

[0036] It should be noted that, in this article, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0037] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An outlet circuit for shortening the non-full-phase operation time in a single-phase mode of a substation line, characterized in that: It includes a first series circuit, a second series circuit and a third series circuit arranged in parallel; The first series circuit includes a first set of intelligent terminal first fault normally open contacts, a first parallel circuit and a starting coil of a first relay connected in series between positive electricity and negative electricity, and the first parallel circuit includes a second set of intelligent terminal A-phase second tripping outlets, a second set of intelligent terminal B-phase second tripping outlets and a second set of intelligent terminal C-phase second tripping outlets arranged in parallel; The second series circuit includes a first set of intelligent terminal second fault normally open contacts, a second parallel circuit and a starting coil of a second relay connected in series between positive electricity and negative electricity, and the second parallel circuit includes a second set of intelligent terminal A phase third tripping outlet, a second set of intelligent terminal B phase third tripping outlet and a second set of intelligent terminal C phase third tripping outlet arranged in parallel; The third series circuit includes a normally open output contact of a first relay connected in series between positive electricity and negative electricity, a normally open output contact of a second relay, and a second set of permanent trip relays of the intelligent terminal.

2. The export circuit for shortening the non-full-phase operation time in the single-phase mode of the substation line according to claim 1 is characterized in that: The condition for closing the fault normally open contacts of the first set of intelligent terminals is that the first set of intelligent terminals fails.

3. The outlet circuit for shortening the non-full-phase operation time in the single-phase mode of the substation line according to claim 1 is characterized in that: The second tripping output of the second intelligent terminal A phase, the second tripping output of the second intelligent terminal B phase, and the second tripping output of the second intelligent terminal C phase are used to start the first relay; The second set of intelligent terminal A phase third tripping output, the second set of intelligent terminal B phase third tripping output and the second set of intelligent terminal C phase third tripping output are used to start the second relay.

4. The outlet circuit for shortening the non-full-phase operation time in the single-phase mode of the substation line according to claim 1 is characterized in that: The normally open output contact of the first relay and the normally open output contact of the second relay are actuated to start the permanent trip relay of the second set of intelligent terminals.

5. The export circuit for shortening the non-full-phase operation time in the single-phase mode of the substation line according to claim 1 is characterized in that: Two relay circuits are used to increase redundancy and reliability.

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