Three-level load unloading device for self-supply switching of low-voltage power distribution system
By designing a self-contained three-level load unloading device for low-voltage power distribution systems, and utilizing a control system composed of incoming line switches, tie switches, and bus tie controllers, the risk of manual operation after transformer power failure is eliminated, automatic power supply switching is achieved, stable power supply to the three-level loads is ensured, and the impact on production and daily life is reduced.
Patent Information
- Application Number
- CN202421854535.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-02
- Publication Date
- 2025-12-02
- Estimated Expiration
- 2034-08-02
AI Technical Summary
In public buildings, after a transformer loses power, the bus tie switch needs to be manually operated to switch power supply, which poses a risk of human error and cannot automatically enable the self-backup operation of three-level loads.
A self-contained three-level load unloading device for a low-voltage power distribution system was designed. Through a control system consisting of the first and second low-voltage incoming line switches, tie switches, and bus tie controller, the power supply circuit is automatically switched to ensure the power supply of the three-level loads when the mains power fails or malfunctions.
It enables automatic switching of power supply when the mains power fails or malfunctions, reducing power outages of three-level loads, minimizing the impact on production and daily life, and avoiding human error.
Smart Images
Figure CN223625623U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of dual-circuit power supply technology, and in particular to a self-contained three-level load unloading device for low-voltage power distribution systems. Background Technology
[0002] In civil buildings, especially public buildings, the power supply typically includes a large number of primary and secondary loads. Transformers in the substation are typically arranged in pairs for mutual backup. The 220 / 380V low-voltage busbars are normally operated in sections, with a tie switch between the two sections. If one section of the busbar loses power, all tertiary loads on both transformers in the same group automatically trip. Simultaneously, the bus tie switch is manually engaged, ensuring power supply to all secondary and higher-level loads on both transformers from the other transformer in the same group. Electrical and mechanical interlocks are installed between the main incoming switch and the bus tie switch. When the mains power is restored, the bus tie switch is manually disconnected, the main incoming switch of the de-energized transformer is closed, and all tertiary loads are manually switched on to restore power. This entire process requires manual operation. To avoid human error, a new type of self-contained tertiary load unloading device for low-voltage power distribution systems is needed. Utility Model Content
[0003] The purpose of this invention is to provide a self-contained three-level load unloading device for low-voltage power distribution systems to solve the problems mentioned in the background art.
[0004] To achieve the above objectives, this utility model provides the following technical solution: a self-contained three-level load unloading device for a low-voltage power distribution system, comprising a first low-voltage incoming switch and a second low-voltage incoming switch. The input terminals of the first low-voltage incoming switch and the second low-voltage incoming switch are provided with power supply units. The output terminals of the first low-voltage incoming switch and the second low-voltage incoming switch are electrically connected to low-voltage outgoing switches for connecting three-level loads. The opening and closing control terminals of the first low-voltage incoming switch and the second low-voltage incoming switch are provided with control components for adjusting the power supply of the circuit.
[0005] Preferably, the control component includes multiple electrical interlock control lines, one end of which is electrically connected to the opening and closing control terminal of the first low-voltage incoming switch, and one end of the other electrical interlock control line is electrically connected to the opening and closing control terminal of the second low-voltage incoming switch. The other ends of the multiple electrical interlock control lines are all electrically connected to a bus tie controller, and the output terminal of the bus tie controller is provided with a connection part for controlling the undervoltage tripping of the low-voltage outgoing switch.
[0006] Preferably, the connection part includes multiple three-level load-cutting non-interlocking lines, one end of which is electrically connected to the first output terminal of the bus tie controller, one end of which is electrically connected to the second output terminal of the bus tie controller, and the other end of which is electrically connected to the signal control terminal of the low-voltage outgoing line switch.
[0007] Preferably, the output terminal of the first low-voltage incoming line switch is electrically connected to a tie switch, and the output terminal of the tie switch is electrically connected to the output terminal of the second low-voltage incoming line switch.
[0008] Preferably, the on / off control terminal of the connecting switch is electrically connected to the third output terminal of the bus tie controller.
[0009] Preferably, the power supply unit includes a first transformer and a second transformer, wherein the output terminal of the first transformer is electrically connected to the input terminal of the first low-voltage incoming switch, and the output terminal of the second transformer is electrically connected to the input terminal of the second low-voltage incoming switch.
[0010] Preferably, the input terminal of the first transformer is electrically connected to a first high-voltage power supply.
[0011] Preferably, the input terminal of the second transformer is electrically connected to a second high-voltage power supply.
[0012] The technical effects and advantages of this utility model are as follows:
[0013] This utility model supplies power to three levels of loads in a public building by stepping down the voltage of the two mains power sources. When one mains power source fails or malfunctions, the control component switches the first low-voltage incoming switch, the second low-voltage incoming switch, and the low-voltage outgoing switch to ensure power supply to the public building in the event of a mains power failure or malfunction, thereby reducing power outages to the three levels of loads and minimizing the impact on production and daily life. Attached Figure Description
[0014] Figure 1 This is a wiring diagram of the entire utility model.
[0015] Figure 2 This is a circuit state table for the entire present invention.
[0016] Figure 3 This is the wiring diagram of the entire utility model.
[0017] Figure 4 This is the control flowchart of the bus tie controller of this utility model.
[0018] In the diagram: 1. First transformer; 101. First high-voltage power supply; 2. Second transformer; 201. Second high-voltage power supply; 3. First low-voltage incoming switch; 4. Second low-voltage incoming switch; 5. Low-voltage outgoing switch; 6. Electrical interlocking control line; 7. Bus tie controller; 8. Three-level load switching non-interlocking line; 9. Tie switch. Detailed Implementation
[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. 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.
[0020] This utility model provides, for example Figure 1-4 The self-provided three-level load unloading device for the low-voltage power distribution system shown includes a first low-voltage incoming switch 3 and a second low-voltage incoming switch 4. The input terminals of the first low-voltage incoming switch 3 and the second low-voltage incoming switch 4 are equipped with power supply units.
[0021] Specifically, the power supply unit includes a first transformer 1 and a second transformer 2. The output terminal of the first transformer 1 is electrically connected to the input terminal of the first low-voltage incoming switch 3, and the output terminal of the second transformer 2 is electrically connected to the input terminal of the second low-voltage incoming switch 4.
[0022] It should be noted that the input terminal of the first transformer 1 is electrically connected to the first high-voltage power supply 101. The input terminal of the second transformer 2 is electrically connected to the second high-voltage power supply 201. Both the first high-voltage power supply 101 and the second high-voltage power supply 201 are 10 kV high voltage.
[0023] The output terminals of both the first low-voltage incoming switch 3 and the second low-voltage incoming switch 4 are electrically connected to a low-voltage outgoing switch 5 for connecting a three-level load.
[0024] The opening and closing control terminals of the first low-voltage incoming switch 3 and the second low-voltage incoming switch 4 are equipped with control components for regulating the power supply of the circuit.
[0025] Specifically, the control component includes multiple electrical interlock control lines 6, one end of which is electrically connected to the opening and closing control terminal of the first low-voltage incoming switch 3, and one end of the other electrical interlock control line 6 is electrically connected to the opening and closing control terminal of the second low-voltage incoming switch 4. The other ends of the multiple electrical interlock control lines 6 are all electrically connected to a bus tie controller 7.
[0026] The output terminal of the bus tie controller 7 is provided with a connection part for controlling the undervoltage trip of the low-voltage outgoing switch 5;
[0027] Specifically, the connection part includes multiple three-level load disconnection lines 8, one end of which is electrically connected to the first output terminal of the bus tie controller 7, one end of which is electrically connected to the second output terminal of the bus tie controller 7, and the other end of which is electrically connected to the signal control terminal of the low-voltage outgoing switch 5.
[0028] The output terminal of the first low-voltage incoming line switch 3 is electrically connected to the tie switch 9. The output terminal of the tie switch 9 is electrically connected to the output terminal of the second low-voltage incoming line switch 4. The opening and closing control terminal of the tie switch 9 is electrically connected to the third output terminal of the bus tie controller 7.
[0029] Specifically, the first low-voltage incoming switch 3 and the second low-voltage incoming switch 4 are respectively installed in the low-voltage incoming cabinets of the two sets of transformers. The tie switch 9 and the bus tie controller 7 are both installed in the tie cabinet. The first low-voltage incoming switch 3, the second low-voltage incoming switch 4 and a tie switch 8 are all connected through the control line led out from the bus tie controller 7. The third-level load disconnection non-interlocking line 8 led out from the bus tie controller 7 is connected to the upper end of the input / output module at the shunt trip and undervoltage release accessory of the third-level load outgoing switch. The specification of the third-level load disconnection non-interlocking line 9 is WDZN-RYJS-2x1.5+WDZN-BYJ-2x2.5.
[0030] As a further improvement to this technical solution, a bus tie controller 7 of a self-contained three-level load unloading device for a low-voltage power distribution system can be connected to the R485 interface of the intelligent meter at the incoming cabinet of the first low-voltage incoming switch 3 and the second low-voltage incoming switch 4 via a MODBUS communication line to read the power (voltage, current) data at the incoming cabinet, thereby enabling the transformer load rate to be determined through the above parameters.
[0031] In actual use, the device is combined with the first low-voltage incoming line switch 3, the second low-voltage incoming line switch 4, and the tie switch 9 through the bus tie controller 7 and the electrical interlock control line 6 to form a "two-incoming-line and one-bus tie system" with manual and automatic control communication. When the bus tie controller 7 detects that the mains power of the first transformer 1 is lost, it will trigger the shunt trip and undervoltage trip of the low-voltage outgoing line switch 5 of the first transformer 1 through the three-level load disconnection non-interlock line 8 according to the load rate of the first transformer 1, and cut off part of the three-level load until the second transformer 2 can meet the power supply of the first and second level loads, and then close the tie switch 9.
[0032] When a power outage occurs due to a fault in the 10kV to 0.4kV transformer or line, if the bus tie controller 7 determines that a single transformer can withstand all the current actual load, the tie switch 9 will automatically close. If the capacity of a single transformer is insufficient, intelligent graded load unloading will be implemented according to preset values.
[0033] When the bus tie controller 7 detects that the low-voltage 0.4kV power supply has returned to normal, it issues an action command. The tie switch 9 automatically disconnects, and the disconnected low-voltage incoming line switch automatically closes. The low voltage returns to the single busbar segmented state. If a third-level load was automatically unloaded before, the third-level load can be manually closed.
[0034] This device supplies power to the three-level loads in a public building by stepping down the two mains power supplies. When one mains power supply fails or malfunctions, the control component switches the first low-voltage incoming switch 3, the second low-voltage incoming switch 4, and the low-voltage outgoing switch 5 to ensure power supply to the public building in the event of a mains power failure or malfunction, thereby reducing power outages to the three-level loads and minimizing the impact on production and daily life.
[0035] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A three-stage load unloading device for self-provided operation of a low-voltage power distribution system, comprising a first low-voltage incoming switch (3) and a second low-voltage incoming switch (4), characterized in that, The input terminals of the first low-voltage incoming line switch (3) and the second low-voltage incoming line switch (4) are equipped with power supply units. The output terminals of the first low-voltage incoming line switch (3) and the second low-voltage incoming line switch (4) are electrically connected to low-voltage outgoing line switches (5) for connecting three-level loads. The opening and closing control terminals of the first low-voltage incoming line switch (3) and the second low-voltage incoming line switch (4) are equipped with control components for adjusting the power supply of the circuit. The control components include multiple electrical interlock control lines (6). One end of one of the electrical interlock control lines (6) is electrically connected to the opening and closing control terminal of the first low-voltage incoming line switch (3), and one end of the other electrical interlock control line (6) is connected to the second low-voltage incoming line switch (4). The opening and closing control terminal of the switch (4) is electrically connected, and the other end of the multiple electrical interlock control lines (6) is electrically connected to the bus tie controller (7). The output terminal of the bus tie controller (7) is provided with a connection part for controlling the undervoltage trip of the low-voltage outgoing switch (5). The connection part includes multiple three-level load cut-off interlock lines (8). One end of one of the three-level load cut-off interlock lines (8) is electrically connected to the first output terminal of the bus tie controller (7), and one end of another three-level load cut-off interlock line (8) is electrically connected to the second output terminal of the bus tie controller (7). The other end of the three-level load cut-off interlock line (8) is electrically connected to the signal control terminal of the low-voltage outgoing switch (5).
2. The self-contained three-level load unloading device for low-voltage power distribution systems according to claim 1, characterized in that, The output terminal of the first low-voltage incoming line switch (3) is electrically connected to a tie switch (9), and the output terminal of the tie switch (9) is electrically connected to the output terminal of the second low-voltage incoming line switch (4).
3. The self-contained three-level load unloading device for low-voltage power distribution systems according to claim 2, characterized in that, The opening and closing control terminal of the connecting switch (9) is electrically connected to the third output terminal of the bus tie controller (7).
4. The self-contained three-level load unloading device for low-voltage power distribution systems according to claim 1, characterized in that, The power supply unit includes a first transformer (1) and a second transformer (2). The output terminal of the first transformer (1) is electrically connected to the input terminal of the first low-voltage incoming switch (3), and the output terminal of the second transformer (2) is electrically connected to the input terminal of the second low-voltage incoming switch (4).
5. The self-contained three-level load unloading device for low-voltage power distribution systems according to claim 4, characterized in that, The input terminal of the first transformer (1) is electrically connected to a first high-voltage power supply (101).
6. The self-contained three-level load unloading device for low-voltage power distribution systems according to claim 4, characterized in that, The input terminal of the second transformer (2) is electrically connected to a second high-voltage power supply (201).