The control circuit of the automatic locking of the relevant protection output after the circuit stops running

Abstract

The utility model discloses a control circuit for automatically locking related protection outlets after a circuit is out of operation. The control circuit includes a detection circuit and an automatic locking circuit. The detection circuit is used to detect the position of the busbar side knife switch, and judge whether the line is in operation according to the position of the busbar side knife switch. The automatic locking circuit includes an auxiliary normally open contact FZJ1 connected in series in each tripping circuit of the line. When the detection circuit detects that the line is out of operation, the auxiliary normally open contact FZJ1 is disconnected, so that the tripping circuit cannot be turned on, and the protection outlets related to the line are automatically locked. The control circuit automatically judges whether each line is in operation by detecting the position of the busbar side knife switch, and when it is judged that a certain line has been out of operation, it can automatically lock the protection outlet function related to the line, which can effectively prevent the malfunction of the protection during the relevant experiments after the line is transferred for maintenance.

Description

Technical Field

[0001] The utility model relates to a control circuit for automatically locking a related protection outlet after a circuit stops running. Background Art

[0002] When the protection devices before the line are focused on the period when the system fails, they selectively cut off the relevant switchgear to ensure the normal and safe operation of the power grid.

[0003] For example, the utility model patent with patent number CN202111454262.1 discloses an improved method and system for preventing false operation of circuit breaker failure protection. The utility model uses the start failure protection signal as the output enable signal or output control signal of the circuit breaker failure protection, thereby avoiding the occurrence of false operation of the circuit breaker failure protection caused by abnormalities such as interference in the secondary circuit of the circuit breaker failure protection device, thereby greatly reducing the workload and operation and maintenance costs of operation and maintenance personnel.

[0004] The utility model patent with patent number CN202111627454.8 also discloses a circuit breaker failure protection optimization method and system based on current waveform recognition. The patent uses the current waveform characteristics to identify CT tailing, comprehensively optimizes the judgment criteria of circuit breaker failure protection, prevents the circuit breaker failure protection from misoperation, greatly enhances the ability to prevent the circuit breaker failure protection from misoperation caused by CT tailing, improves the reliability of circuit breaker failure protection, and ensures the safe and stable operation of the power system.

[0005] The above utility model only considers the control logic and optimization method of the relevant protection when the line is in normal operation, but does not consider the risk of malfunction of the protection caused by the failure to exit the relevant protection involved in the line after the line is out of operation. If after a line is out of operation, the tripping protection related to the line (such as the line protection of the line, the bus differential and the protection outlet of the main transformer for the line switch) and the start-up failure protection of this line acting on other protections are not exited, it may cause the bus differential and other protections to malfunction due to the false start of the start-up failure during the relevant tests after the line is turned over for maintenance, or cause personal safety accidents for maintenance personnel due to the tripping of the line switch.

[0006] Therefore, in the face of the risk of false protection operation caused by the failure of related protection involved in the line to exit operation after the current line is shut down, it is a technical problem that needs to be solved urgently to develop a protection output circuit that can automatically lock the protection related to the line after the line is shut down. Utility Model Content

[0007] The utility model aims to provide a control circuit for automatically locking related protection outlets after a circuit is out of operation, so as to solve the problem of the risk of protection malfunction caused by the related protection involved in the line not being out of operation after the line is out of operation.

[0008] In order to solve the above technical problems, the utility model provides a control circuit for automatically locking the relevant protection outlet after the circuit stops running, comprising:

[0009] The detection circuit is used to detect the position of the busbar side switch and determine whether the line is in operation according to the position of the busbar side switch;

[0010] The automatic locking circuit includes an auxiliary normally open contact FZJ1 connected in series in each tripping circuit of the line. When the detection circuit detects that the line has exited operation, the auxiliary normally open contact FZJ1 is disconnected, making the tripping circuit unable to conduct, and automatically locking the protection output related to the line.

[0011] Furthermore, the detection circuit includes a relay FZJ and an auxiliary normally open contact ML of the bus side knife switch, and the relay FZJ and the auxiliary normally open contact ML are connected in series between the bus positive pole and the bus negative pole. When the bus side knife switch is in the open position, the auxiliary normally open contact ML is disconnected; when the bus side knife switch is in the closed position, the auxiliary normally open contact ML is closed.

[0012] Furthermore, the detection circuit also includes a manual control circuit, which includes an auxiliary handle S1 and an auxiliary handle S2, the auxiliary handle S2 is connected in series with the auxiliary normally open contact ML, and the auxiliary handle S1 is connected in parallel to both ends of the series-connected auxiliary handle S2 and the auxiliary normally open contact ML.

[0013] Furthermore, the control circuit also includes a monitoring circuit, which includes an LED lamp and an auxiliary normally open contact TWJ1 of the trip position relay TWJ; the LED lamp and the auxiliary normally open contact TWJ1 are connected in series between the positive pole of the bus and the negative pole of the bus.

[0014] The beneficial effects of the utility model are as follows: by detecting the position of the busbar side knife switch, it is automatically determined whether each line is in operation, and when it is determined that a line has exited operation, the protection outlet function related to the line can be automatically locked, which can effectively prevent the malfunction of the protection during the relevant experiments after the line is transferred for maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The same reference numerals are used in these drawings to represent the same or similar parts. The exemplary embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0016] Figure 1 It is a structural schematic diagram of an embodiment of the utility model;

[0017] Figure 2This is the locking principle of the utility model for protection against start failure. DETAILED DESCRIPTION

[0018] like Figure 1 The control circuit for automatically locking the relevant protection outlets after the circuit shown in the figure is out of operation includes a detection circuit and an automatic locking circuit. Among them, the detection circuit is used to detect the position of the busbar side knife switch, and judge whether the line is in operation according to the position of the busbar side knife switch; the automatic locking circuit includes an auxiliary normally open contact FZJ1 connected in series in each tripping circuit of the line. When the detection circuit detects that the line is out of operation, the auxiliary normally open contact FZJ1 is disconnected, so that the tripping circuit cannot be turned on, and the protection outlets related to the line are automatically locked. The control circuit automatically determines whether each line is in operation by detecting the position of the busbar side knife switch, and when it is determined that a certain line has been out of operation, it can automatically lock the protection outlet function related to the line, which can effectively prevent the malfunction of the protection during the relevant experiments after the line is transferred for maintenance. In addition, the application of the control circuit can replace the step of manually exiting the relevant protection pressure plate after the line is out of operation, reducing the workload and operation risks of the operation and maintenance personnel.

[0019] According to one embodiment of the present application, the detection circuit includes a relay FZJ and an auxiliary normally open contact ML of a busbar side knife switch, wherein the relay FZJ and the auxiliary normally open contact ML are connected in series between the positive pole of the busbar and the negative pole of the busbar. When the busbar side knife switch is in the open position, the auxiliary normally open contact ML is disconnected; when the busbar side knife switch is in the closed position, the auxiliary normally open contact ML is closed. The position of the busbar side knife switch is detected by introducing the auxiliary normally open contact ML of the busbar side knife switch. The relay FZJ is used to characterize the on-off state of the detection circuit. The opening and closing state of the auxiliary normally open contact ML is introduced into each tripping circuit of the line through the auxiliary normally open contact FZJ1 of the relay FZJ, thereby realizing the function of automatically locking the tripping circuit after the auxiliary normally open contact ML is disconnected.

[0020] exist Figure 1 In the tripping circuit in, TJ is the tripping contact. When the protection issues a tripping command, the tripping contact TJ closes instantaneously and then returns; DL is the auxiliary normally open contact of the circuit breaker. When the circuit breaker is in the open position, the circuit breaker DL closes; TQ is the tripping coil. When the tripping coil TQ is energized, it will drive the circuit breaker to trip. Add the auxiliary normally open contact FZJ1 of the FZJ relay to the tripping circuit. When the busbar side knife switch is in the open position, the auxiliary normally open contact ML is disconnected, the relay FZJ loses power, and the auxiliary normally open contact FZJ1 is disconnected. At this time, regardless of whether the tripping protection pressure plate is withdrawn, the tripping circuit has been locked (disconnected), that is, the function of automatically locking the related tripping protection of the line after the line is out of operation is realized.

[0021] According to one embodiment of the present application, the detection circuit also includes a manual control circuit, which includes an auxiliary handle S1 and an auxiliary handle S2, wherein the auxiliary handle S2 is connected in series with the auxiliary normally open contact ML, and the auxiliary handle S1 is connected in parallel to both ends of the series-connected auxiliary handle S2 and the auxiliary normally open contact ML. When the auxiliary normally open contact ML is abnormally displaced, the auxiliary normally open contact ML can be forced to be connected or disconnected by manually controlling the auxiliary handle S1 and the auxiliary handle S2, thereby effectively avoiding the impact of the abnormal displacement of ML in the present invention. The detection circuit can be switched to the following states by the auxiliary handle S1 and the auxiliary handle S2:

[0022] State 1: S1=0, S2=1 is automatic dynamic state. At this time, the circuit on-off status is only related to ML. When ML is closed, the FZJ relay is energized, and when ML is disconnected, the FZJ relay is de-energized.

[0023] State 2: S1=1, S2=0 is the forced enabling state. At this time, no matter whether ML is closed or not, the FZJ relay is energized.

[0024] State 3: S1=0, S2=0 is the forced disconnection state. At this time, no matter whether ML is closed or not, the FZJ relay will not be energized.

[0025] According to one embodiment of the present application, the control circuit also includes a monitoring circuit, which includes an LED lamp and an auxiliary normally open contact TWJ1 of a trip position relay TWJ; the LED lamp and the auxiliary normally open contact TWJ1 are connected in series between the positive pole of the bus and the negative pole of the bus.

[0026] When the auxiliary contact position control circuit of the busbar side knife switch is in state 1 and the auxiliary normally open contact ML is disconnected, the auxiliary normally open contact FZJ1 is also disconnected, and the relay TWJ is not energized. Therefore, the auxiliary normally open contact TWJ1 is disconnected and the LED goes out, indicating that the line tripping circuit is in a locked state at this time; conversely, when the auxiliary normally open contact ML is closed, the LED lights up, indicating that the line tripping circuit is in normal working condition.

[0027] The utility model can realize the automatic exit of related tripping protection after the line is out of operation, and also has the following functions:

[0028] 1. When the auxiliary normally open contact ML of the busbar side knife switch fails, that is, the auxiliary normally open contact ML does not correspond to the actual position of the busbar side knife switch, it can be discovered through the LED light of the monitoring circuit. That is, when the busbar side knife switch is actually in the open position and the auxiliary normally open contact ML is in the closed position, the LED light is on. At this time, the detection circuit can be turned to state 3 to force the tripping circuit to be locked; conversely, when the busbar side knife switch is actually in the closed position and the auxiliary normally open contact ML is in the open position, the detection circuit can be turned to state 2 to ensure the normal use effect of the utility model when the auxiliary normally open contact ML of the busbar side knife switch is abnormal.

[0029] 2. When the line needs to be inspected and repaired and related electrical tests such as transmission are required, if certain tripping protections need to be activated, it is only necessary to switch the detection circuit corresponding to the protection to state 2 to release the lock of the protection.

[0030] like Figure 2 As shown, the locking logic of the start failure protection of the utility model is: since the start failure protection action of the line needs to meet the two conditions that the line tripping protection action and the fault current of the tripping corresponding switch continue to exist, and since the utility model has automatically locked its related protection tripping circuit after the line is out of operation, that is, the action condition of the start failure will not be met, the utility model does not need to add other control links to realize the automatic locking function of the start failure protection.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A control circuit for automatically locking the relevant protection outlet after the circuit stops running, characterized in that: include: A detection circuit is used to detect the position of the busbar side knife switch, and judge whether the line is in operation according to the position of the busbar side knife switch; the detection circuit includes a relay FZJ and an auxiliary normally open contact ML of the busbar side knife switch, the relay FZJ and the auxiliary normally open contact ML are connected in series between the positive pole of the busbar and the negative pole of the busbar, when the busbar side knife switch is in the open position, the auxiliary normally open contact ML is disconnected; when the busbar side knife switch is in the closed position, the auxiliary normally open contact ML is closed; The automatic locking circuit includes an auxiliary normally open contact FZJ1 connected in series in each tripping circuit of the line. When the detection circuit detects that the line has exited operation, the auxiliary normally open contact FZJ1 is disconnected, making the tripping circuit unable to conduct, and automatically locking the protection output related to the line.

2. The control circuit according to claim 1, characterized in that: The detection circuit also includes a manual control circuit, which includes an auxiliary handle S1 and an auxiliary handle S2. The auxiliary handle S2 is connected in series with the auxiliary normally open contact ML, and the auxiliary handle S1 is connected in parallel to both ends of the series-connected auxiliary handle S2 and the auxiliary normally open contact ML.

3. The control circuit according to claim 2, characterized in that: The control circuit also includes a monitoring circuit, which includes an LED lamp and an auxiliary normally open contact TWJ1 of a trip position relay TWJ; the LED lamp and the auxiliary normally open contact TWJ1 are connected in series between the positive pole of the busbar and the negative pole of the busbar.

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