A blocking circuit to prevent 400V bus tripping
By designing a blocking circuit to prevent accidental bus tripping in a 400V power distribution system, and utilizing the dual detection mechanism of the incoming switch status unit and the bus tie switch control unit, the problem of accidental bus tie switch tripping was solved, ensuring power supply continuity and maintenance safety, and improving the system's operational flexibility and reliability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- FUJIAN HONGSHAN THERMOELECTRICITY
- Filing Date
- 2025-07-25
- Publication Date
- 2026-05-26
AI Technical Summary
In 400V power distribution systems, bus tie switches are prone to tripping due to misjudgment of the closed loop state, leading to power outages. Furthermore, the existing interlocking logic does not take into account the mechanical position of the switch, affecting maintenance safety and operational flexibility.
Design an interlocking circuit to prevent 400V bus malfunctions. By integrating the electrical status and mechanical position of the incoming line switch status unit and the bus tie switch control unit, a dual detection mechanism and intelligent interlocking architecture are adopted. Combined with a three-color indicator light to display the system status, precise control of the bus tie switch is achieved.
It eliminates bus tie malfunctions, ensures power supply continuity, improves operation and maintenance efficiency, supports uninterrupted maintenance, and enhances power supply reliability and overall availability.
Smart Images
Figure CN224289290U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of low-voltage power distribution protection technology, specifically a blocking circuit to prevent erroneous tripping of a 400V bus. Background Technology
[0002] In 400V power distribution systems in industrial sectors such as power plants, substations, and chemical plants, segmented busbar structures are commonly used to improve power supply reliability. A typical configuration divides the 400V busbar into two sections, PCA and PCB, and connects the two sections via a bus tie switch (hereinafter referred to as the bus tie switch). Under normal operating conditions, each busbar is powered by its own incoming power supply, and the bus tie switch is in the open state. Simultaneously, when the incoming power supply of one busbar (e.g., PCA section) needs maintenance, the bus tie switch can be closed, allowing the incoming power supply of the other busbar (PCB section) to power the load of PCA section, thus ensuring power continuity. However, this maintenance method has the following shortcomings:
[0003] 1. Risk of false tripping: When the incoming power switch of PC A section is out of maintenance and the load of PC A section is powered by PC B section through the bus tie switch, if it is necessary to perform a transmission test (such as a switching operation test) on the incoming power switch of PC A section, the existing interlocking circuit will be mistakenly judged as an abnormal closed loop state of "both incoming switches and the bus tie switch are closed at the same time", which will trigger the interlocking tripping circuit, causing the bus tie switch to be falsely tripped, resulting in the loss of power to the PC A section bus and thus causing a system shutdown accident.
[0004] 2. Insufficient safety during maintenance: The existing interlocking logic is based only on the electrical state of the switch (closed / open), without considering the mechanical position state of the switch (operating position / test position / maintenance position). Therefore, when the incoming switch is in the test or maintenance position, its opening and closing operations are only for testing or maintenance needs and should not trigger the bus tie switch to trip. However, in actual operation, it is impossible to distinguish such working conditions, which will lead to unnecessary interlocking actions.
[0005] 3. Limited operational flexibility: Under special operating conditions (such as single-section busbar maintenance), there is a lack of an effective interlocking mechanism for the operation of the bus tie switch. This may result in the reliability of power supply being affected by accidental tripping, or the inability to perform necessary switching operations due to excessive interlocking. Utility Model Content
[0006] The purpose of this invention is to provide a blocking circuit to prevent 400V bus from tripping erroneously, so as to solve the problems mentioned in the background art.
[0007] To achieve the above objectives, this utility model provides the following technical solution: a blocking circuit to prevent 400V bus malfunction and trip, comprising:
[0008] Incoming line switch status unit: electrically connected to PC A section incoming line switch-QF1 and PC B section incoming line switch-QF2;
[0009] Bus tie switch control unit: electrically connected to bus tie switch-Q1;
[0010] The incoming line switch status unit and the bus tie switch control unit are electrically connected through an interlocking execution unit.
[0011] Furthermore, the interlocking execution unit includes a DCS module and a selection switch. The DCS module and the selection switch are connected in parallel. At the same time, the DCS module and the selection switch are electrically connected to the PC A section incoming line switch-QF1, the PC B section incoming line switch-QF2, and the bus tie switch-Q1.
[0012] Furthermore, it also includes indicator lights-H1, H2, and H3, which are electrically connected between the incoming line switch status unit and the bus tie switch control unit.
[0013] Furthermore, both the DCS module and the selector switch are electrically connected via a manual operation switch SW.
[0014] Furthermore, one end of the indicator light-H1 is electrically connected to port 22 of the bus tie switch-Q1, one end of the indicator light-H2 is electrically connected to port 24 of the bus tie switch-Q1, and the other ends of both the indicator light-H1 and the indicator light-H2 are electrically connected to the PCA section incoming line switch-QF1.
[0015] One end of the indicator light-H3 is electrically connected to the B3 port of the bus tie switch-Q1, and the other end of the indicator light-H3 is electrically connected to the PCA section incoming switch-QF1 and the PCB section incoming switch-QF2.
[0016] Furthermore, the manual operation switch SW includes switches 12, 34, 56, and 78. Switches 12 and 56 are electrically connected to the DCS module, and switches 34 and 78 are electrically connected to a selector switch.
[0017] Furthermore, the DCS module includes a BC submodule and a BT submodule, the selection switch includes an S1E switch and an S2E switch, the BC submodule is electrically connected to switch 12, the BT submodule is electrically connected to switch 56, the BC submodule is electrically connected to switch S1E, and the S1E switch is electrically connected to switch 34.
[0018] Compared with the prior art, the beneficial effects of this utility model are:
[0019] This invention integrates the electrical status of the incoming line switches of PC A and PC B sections with the mechanical position of the selector switches. Through a dual detection mechanism of electrical status and mechanical position and an intelligent interlocking architecture, it can completely eliminate bus tie malfunctions during maintenance and testing, ensuring power supply continuity. Simultaneously, the system status can be intuitively displayed through a three-color indicator light group, thereby improving operation and maintenance efficiency. Furthermore, the automatic interlocking technology of the test / maintenance position signals allows the interlocking system to support uninterrupted maintenance operations while ensuring anti-loop function, thus improving overall availability. Attached Figure Description
[0020] Figure 1 This is a circuit diagram of the locking circuit of this utility model. Detailed Implementation
[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0022] refer to Figure 1 This embodiment provides a lockout circuit to prevent erroneous tripping of the 400V bus. The lockout circuit includes an incoming line switch status unit, a bus tie switch control unit, and an interlocking execution unit. In this embodiment, the incoming line switch status unit is electrically connected to the PCA section incoming line switch-QF1 and the PC B section incoming line switch-QF2, used to collect the closing status signals and test / maintenance mechanical position signals of the PCA and PC B sections. The bus tie switch control unit is electrically connected to the bus tie switch-Q1, used to adjust the state of the bus tie switch-Q1 according to the tripping command. The interlocking execution unit is electrically connected to the incoming line switch status unit and the bus tie switch control unit, used to trigger a tripping command and disconnect the bus tie switch-Q1 when the closing status signal is high (i.e., the PCA section incoming line switch-QF1 and the PC B section incoming line switch-QF2 are closed simultaneously). Meanwhile, when any of the mechanical position signals of the test / maintenance position is triggered (i.e., PCA section incoming switch-QF1 and / or PC B section incoming switch-QF2 are in the test / maintenance position), the trip command will not be triggered, and the bus tie switch-Q1 will remain in operation.
[0023] Furthermore, the interlocking execution unit includes a DCS module and a selector switch. The DCS module and the selector switch are connected in parallel, and both are electrically connected to the PCA section incoming switch-QF1, the PCB section incoming switch-QF2, and the bus tie switch-Q1. In this embodiment, the DCS module and the selector switch are electrically connected via manual operation switches SW. Specifically, the manual operation switches SW include switches 12, 34, 56, and 78. Switches 12 and 56 are electrically connected to the DCS module, and switches 34 and 78 are electrically connected to the selector switch.
[0024] Furthermore, the DCS module includes a BC submodule and a BT submodule, and the selector switches include an S1E switch and an S2E switch. The S1E switch is a test position switch, and the S2E switch is a maintenance position switch. In this embodiment, the BC submodule is electrically connected to switch 12, the BT submodule is electrically connected to switch 56, and the BC submodule is also electrically connected to switch S1E, which in turn is electrically connected to switch 34.
[0025] In other words, this embodiment monitors the closing status of PCA and PCB sections, as well as the signals from switches S1E and S2E in real time, and outputs corresponding trip and lockout signals based on the monitored signals to regulate the status of bus tie switch-Q1. Specifically, when both PCA and PCB sections are closed and neither switch S1E nor switch S2E is activated, bus tie switch-Q1 is in the open state, and the incoming switch-QF1 of PCA section is not in the test position, while the incoming switch-QF2 of PCB section is not in the maintenance position. Specifically, when the incoming switches-QF1 of PCA section, QF2 of PCB section, and bus tie switch-Q1 are closed simultaneously, a trip command is triggered via a trip signal, and bus tie switch-Q1 is disconnected via the DCS module and the manual operation switch SW.
[0026] In this embodiment, the incoming line switch status unit and the bus tie switch control unit are electrically connected via indicator lights -H1, -H2, and -H3. One end of indicator light -H1 is electrically connected to port 22 of the bus tie switch -Q1, and one end of indicator light -H2 is electrically connected to port 24 of the bus tie switch -Q1. The other ends of both indicator lights -H1 and -H2 are electrically connected to the PCA section incoming line switch -QF1. One end of indicator light -H3 is electrically connected to port B3 of the bus tie switch -Q1, and the other end of indicator light -H3 is electrically connected to both the PC A section incoming line switch -QF1 and the PC B section incoming line switch -QF2.
[0027] In other words, when both PC A and PC B are in the open state, indicator light H1 activates, meaning bus tie switch Q1 can be closed. Furthermore, when the selector switch is in the test / maintenance position, i.e., when either switch S1E or S2E is closed, indicator light H2 activates, and the interlocking unit temporarily locks the circuit. Even further, when bus tie switch Q1 is tripped via the interlocking unit, indicator light H3 activates.
[0028] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended embodiments and their equivalents.
Claims
1. A blocking circuit to prevent 400V bus malfunction and tripping, characterized in that, Including: Incoming line switch status unit: electrically connected to PC A section incoming line switch-QF1 and PC B section incoming line switch-QF2; Bus tie switch control unit: electrically connected to bus tie switch-Q1; The incoming line switch status unit and the bus tie switch control unit are electrically connected through an interlocking execution unit.
2. The interlocking circuit for preventing 400V bus tripping as described in claim 1, characterized in that, The interlocking execution unit includes a DCS module and a selector switch. The DCS module and the selector switch are connected in parallel. At the same time, the DCS module and the selector switch are electrically connected to the PCA section incoming switch-QF1, the PCB section incoming switch-QF2 and the bus tie switch-Q1.
3. The interlocking circuit for preventing 400V bus tripping as described in claim 1, characterized in that, It also includes indicator lights-H1, H2 and H3, and the incoming line switch status unit and the bus tie switch control unit are electrically connected through indicator lights-H1, H2 and H3.
4. The interlocking circuit for preventing 400V bus tripping as described in claim 2, characterized in that, Both the DCS module and the selector switch are electrically connected via a manual operation switch SW.
5. The interlocking circuit for preventing 400V bus tripping as described in claim 3, characterized in that, One end of the indicator light-H1 is electrically connected to port 22 of the bus tie switch-Q1, one end of the indicator light-H2 is electrically connected to port 24 of the bus tie switch-Q1, and the other ends of the indicator light-H1 and the other ends of the indicator light-H2 are both electrically connected to the PCA section incoming line switch-QF1. One end of the indicator light-H3 is electrically connected to the B3 port of the bus tie switch-Q1, and the other end of the indicator light-H3 is electrically connected to the PCA section incoming switch-QF1 and the PCB section incoming switch-QF2.
6. The interlocking circuit for preventing 400V bus tripping as described in claim 4, characterized in that, The manual operation switch SW includes switches 12, 34, 56, and 78. Switches 12 and 56 are electrically connected to the DCS module, and switches 34 and 78 are electrically connected to the selector switch.
7. The interlocking circuit for preventing 400V bus tripping as described in claim 6, characterized in that, The DCS module includes a BC submodule and a BT submodule. The selection switch includes an S1E switch and an S2E switch. The BC submodule is electrically connected to switch 12, the BT submodule is electrically connected to switch 56, and the BC submodule is electrically connected to switch S1E. The S1E switch is electrically connected to switch 34.