A kind of overload prevention device under the running state of emergency power supply of multi-transformer interconnection

Abstract

The utility model discloses a kind of overload prevention and control devices under the operation state of multiple transformer liaison emergency power supply, including at least two groups of power supply system and load control cabinet, the power supply system includes transformer, transformer is connected with low-voltage outgoing line bus section by incoming line master switch, first outgoing line switch is equipped on low-voltage outgoing line bus section, first outgoing line switch is connected with the loadable load in electric power load end, second outgoing line switch is equipped on low-voltage outgoing line bus section, second outgoing line switch is connected with the unremovable load in electric power load end;Connection switch is equipped between low-voltage outgoing line bus section in two groups of power supply system, first outgoing line switch, incoming line master switch and connection switch are connected with load control cabinet respectively, in normal state, incoming line master switch is closed, connection switch is disconnected.Compared with prior art, the automatic switching of connection switch is realized to ensure the power supply continuity of important load, as no manual duty, reduce manpower cost.

Description

Technical Field

[0001] This utility model relates to the field of building electrical systems, and in particular to an overload prevention and control device for emergency power supply operation of multiple transformers interconnected. Background Technology

[0002] The single busbar segmentation on the low-voltage side of a transformer is the most common low-voltage connection method. By setting up a tie switch, two or more transformers are connected, and the continuity and reliability of power supply are ensured by opening and closing the bus tie switch.

[0003] Article 3.2.11 of the "Standard for Electrical Design of Civil Buildings" (GB51348-2019) stipulates that when a building is powered by dual power sources and both transformers have bus tie switches on their low-voltage sides, secondary loads can be powered by a single circuit from either low-voltage busbar. Therefore, when a project uses dual power sources, secondary loads on the low-voltage side with bus tie switches are often powered by a single circuit, saving initial investment costs. Article 3.3.2 of the "Design Code for 20kV and Below Substations" (GB50053-2013) stipulates that in substations equipped with two or more transformers, when any one transformer is disconnected, the capacity of the remaining transformers should be sufficient to meet the power needs of all primary and secondary loads. Therefore, in transformer selection and design, the capacity of a single transformer is designed to meet the power needs of all primary and secondary important loads in the transformer group's distribution, and the design load rate of a single transformer during normal operation generally does not exceed 85%, while the actual operating load rate is a variable value.

[0004] When a transformer suddenly fails, there are generally three handling options for the tie switch: Option 1: Do not take any action on the load and directly close the tie switch. This option may cause the transformer to overload. Under overload conditions, the transformer temperature rises, leading to insulation aging and affecting the transformer's lifespan. Especially when the overload is too large, it can cause the normal transformer to trip, affecting the reliability of important loads. Option 2: Directly disconnect all tertiary loads, and the tie switch will automatically close. This option will not cause transformer overload. However, when the transformer load rate is low and a single transformer can fully drive the entire operating load, blindly disconnecting tertiary loads can have a certain impact on the power supply area. Option 3: Manually analyze the load rate of the two transformers, calculate, and decide whether to disconnect or not disconnect some tertiary loads, and manually close the bus tie switch to ensure that the transformer is not overloaded and to reduce the impact of the power outage. Since manual switching takes a certain amount of time, it will have a certain impact on the interruption time of the secondary loads supplied by a single circuit. Summary of the Invention

[0005] The purpose of this utility model is to provide an overload prevention and control device for emergency power supply operation of multiple transformers interconnected. The technical problem to be solved is to realize the automatic opening and closing of the interconnection switch.

[0006] To solve the above problems, this utility model adopts the following technical solution: an overload prevention and control device for emergency power supply operation of multiple transformers interconnected, characterized in that: it includes at least two power supply systems and a load control cabinet. The power supply system includes a transformer, which is electrically connected to a low-voltage outgoing bus section through an incoming main switch. A first outgoing switch is provided on the low-voltage outgoing bus section, which is electrically connected to an unloadable load at the load end. A second outgoing switch is provided on the low-voltage outgoing bus section, which is electrically connected to a non-unloadable load at the load end. A connecting switch is provided between the low-voltage outgoing bus sections of the two power supply systems. The first outgoing switch, the incoming main switch, and the connecting switch are respectively connected to the load control cabinet. Under normal conditions, the incoming main switch is closed, and the connecting switch is open.

[0007] Furthermore, the main incoming switch is connected to the load control cabinet via a signal line.

[0008] Furthermore, the first outgoing switch is connected to the load control cabinet via a signal line, and sends data to the load control cabinet via the signal line.

[0009] Furthermore, the first outgoing switch is also connected to the load control cabinet via a hard wire to receive control signals from the load control cabinet.

[0010] Furthermore, the communication switch is connected to the load control cabinet via a hard wire.

[0011] Furthermore, the load control cabinet includes a signal receiving device, a data analysis device, a load control transmitting device, and a control panel. The data analysis device is connected to the signal receiving device, the load control transmitting device, and the control panel, respectively. The main incoming switch and the first outgoing switch are connected to the signal receiving device, and the first outgoing switch and the tie switch are connected to the load control transmitting device.

[0012] Furthermore, when a transformer in one or more power supply systems fails, the load control cabinet obtains the first power of each transformer, the second power of the first outgoing switch, and the status of the incoming main switch (either energized or de-energized) from the previous moment. It then determines the first power of the transformers in all power supply systems. If the sum of the first power of the transformers in all power supply systems is less than the limited power of the remaining transformers, the load control cabinet controls the tie switch to close. If the sum of the first power of the transformers in all power supply systems is greater than the limited power of the remaining transformers, the load control cabinet controls the first outgoing switch in part or all of the power supply systems to open and then controls the tie switch to close.

[0013] Compared with the prior art, this utility model sets up a load control cabinet and connects the incoming main switch, the first outgoing switch connected to the low-voltage outgoing bus section on the unloadable load, and the tie switch in each power supply system to the load control cabinet. This enables the load control cabinet to determine whether the transformer is faulty by monitoring the status of the incoming main switch. When one of the transformers fails, the load control cabinet closes or opens part or all of the first outgoing switches according to the total power of the power supply system and then closes the tie switch, realizing the automatic opening and closing of the tie switch to ensure the continuity of power supply to important loads. Since no manual operation is required, labor costs are reduced. Attached Figure Description

[0014] Figure 1 This is a connection diagram of this utility model. Detailed Implementation

[0015] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0016] like Figure 1 As shown, this utility model discloses an overload prevention and control device for emergency power supply operation of multiple transformers interconnected. Its features include: two power supply systems 1 and a load control cabinet 3. Each power supply system 1 includes a transformer 11. The transformers 11 of both power supply systems are electrically connected to a low-voltage outgoing bus section 13 via an incoming main switch 12. A first outgoing switch 14 is provided on the low-voltage outgoing bus section 13, which is electrically connected to an unloadable load 21 in the load terminal 2. A second outgoing switch 15 is provided on the low-voltage outgoing bus section 13, which is electrically connected to a non-unloadable load 22 in the load terminal 2. A connecting switch 16 is provided between the low-voltage outgoing bus sections 13 of the two power supply systems 1. The first outgoing switch 14, the incoming main switch 12, and the connecting switch 16 are respectively connected to the load control cabinet 3. Under normal conditions, the incoming main switch 12 is closed, and the connecting switch 16 is open.

[0017] In the existing technology, loads are divided into three levels. The third level load is an unloadable load, which is a normal load, while the first and second level loads are non-unloadable loads, which are important loads.

[0018] The following describes the two power supply systems in detail. Power supply system 1A includes transformer A 111, which is connected to low-voltage outgoing bus section A 131 via main incoming switch A 121. Low-voltage outgoing bus section A 131 is equipped with a first outgoing switch A 141 and a second outgoing switch A 151. The first outgoing switch A 141 connects to existing unloadable loads, and the second outgoing switch A 151 connects to non-unloadable loads. Power supply system 1B includes transformer B 112, which is connected to low-voltage outgoing bus section B 132 via main incoming switch B 122. Low-voltage outgoing bus section B 132 is equipped with a first outgoing switch B 142 and a second outgoing switch B 152. The first outgoing switch B 142 connects to existing unloadable load 4, and the second outgoing switch A 151 connects to non-unloadable load 4. 152 connects to the non-unloadable load 5; a connecting switch 16 is provided between the main incoming switch A121 and the main incoming switch B122 of the two power supply systems. In this utility model, the load control cabinet 3 adopts the load control cabinet 3 of the prior art, which mainly includes a signal receiving device 31, a data analysis device 32, a load control transmitting device 33 and a control panel 34. The data analysis device 32 is equipped with power analysis software, which is the prior art. The data analysis device 32 is connected to the signal receiving device 31, the load control transmitting device 33 and the control panel 34 respectively. The control panel 34 is used for human-machine interaction, inputting and displaying data. The data here is power data, and the input data is the power limit value data of the transformer.

[0019] The incoming main switch A121 and incoming main switch B122 are connected to the signal receiving device 31 via signal lines. The first outgoing switch A141 and first outgoing switch B142 are also connected to the signal receiving device 31 via signal lines, and send data to the signal receiving device 31 via signal lines. The first outgoing switch A141 and first outgoing switch B142 are also connected to the load control transmitting device 33 via hard wires, and receive control signals from the load control cabinet 3 via hard wires. The tie switch 16 is connected to the load control transmitting device 33 via hard wires. The hard wire connection is not affected by electromagnetic interference and external signal interference, so there is no need to use a specific communication protocol for signal transmission.

[0020] In normal operation (normal state), the main incoming switch A 121 and main incoming switch B 122 are closed (conducting), and the connecting switch 16 is open. The two power supply systems operate independently. The signal receiving device 31 receives the power data of the main incoming switch A 121, main incoming switch B 122, first outgoing switch A141, and second outgoing switch B142, thereby monitoring the total load of the transformer and the load of the first outgoing switch. The data analysis device 32 can also determine the status of transformer A111 and transformer B112 based on the power data of the main incoming switch A121 and the second main incoming switch B122, indicating whether there is power. When the power data is 0, it is determined that there is no power; otherwise, it is determined that there is power.

[0021] When a transformer 11 in one of the power supply systems 1 fails, the load control cabinet 3 obtains the first power of each transformer, the second power of the first outgoing switch 14, and the status of the incoming main switch 12 at the previous moment. The status of the incoming main switch 12 is determined based on the second power: when the second power is 0, there is no power; when the second power is greater than 0, there is power. The load control cabinet 3 also determines the first power of all transformers 11 in all power supply systems 1. When the sum of the first power of all transformers 11 in all power supply systems 1 is less than the limited power of the remaining transformers 11, the load control cabinet 3 controls the tie switch 16 to close. This ensures that the tie switch automatically closes without overloading the transformers, guaranteeing the continuity and reliability of power supply to important loads. In this invention, the sum of the first power is the sum of the power of the transformers 11 in the power supply systems 1 that are connected by the tie switch 16 between the two power supply systems 1.

[0022] When the first power of transformer 11 in all power supply systems 1 is greater than the limited power of the remaining transformer 11, the load control cabinet 3 controls the first outgoing switch 14 in part or all of the power supply systems 1 to open and then controls the tie switch 16 to close; thereby reducing the power outage area of ​​ordinary loads.

[0023] The power limit is 80-100% of the rated power of a single transformer, which can be manually entered through the control panel 34.

[0024] When the faulty transformer is restored to power, the load control cabinet 3 receives the second power from the incoming main switch of the faulty transformer and determines that the second power is greater than 0, thus indicating a live state. The load control cabinet 3 sends a disconnect command to the tie switch 16 through the load control transmitting device 33. The tie switch 16 automatically disconnects upon receiving the disconnect command. If the first outgoing switch 14 is disconnected, the load control cabinet 3 sends a closing command to the disconnected first outgoing switch 14 through the load control transmitting device 33. The first outgoing switch 14 closes, restoring the load to the state before the transformer fault, without manual intervention. Through the participation of the overload control cabinet, the tie switch automatically switches on and off, ensuring the continuity and reliability of power supply to important loads, preventing transformer overload that could affect its lifespan, reducing the area affected by power outages for ordinary loads, and reducing labor costs.

Claims

1. An overload prevention device for emergency power supply operation involving multiple transformers interconnected, characterized in that: The system includes at least two power supply systems (1) and a load control cabinet (3). The power supply system (1) includes a transformer (11). The transformer (11) is electrically connected to the low-voltage outgoing bus section (13) through the incoming main switch (12). The low-voltage outgoing bus section (13) is equipped with a first outgoing switch (14). The first outgoing switch (14) is electrically connected to the unloadable load (21) in the power load end (2). The low-voltage outgoing bus section (13) is equipped with a second outgoing switch (15). The second outgoing switch (15) is electrically connected to the non-unloadable load (22) in the power load end (2). A tie switch (16) is provided between the low-voltage outgoing bus sections (13) in the two power supply systems (1). The first outgoing switch (14), the incoming main switch (12), and the tie switch (16) are respectively connected to the load control cabinet (3). Under normal conditions, the incoming main switch (12) is closed and the tie switch (16) is open.

2. The overload prevention and control device for emergency power supply operation of multiple transformers as described in claim 1, characterized in that: The main incoming switch (12) is connected to the load control cabinet (3) via a signal line.

3. The overload prevention device for emergency power supply operation of multiple transformers interconnected as described in claim 1, characterized in that: The first outgoing switch (14) is connected to the load control cabinet (3) via a signal line and sends data to the load control cabinet (3) via the signal line.

4. The overload prevention and control device for emergency power supply operation of multiple transformers interconnected as described in claim 3, characterized in that: The first outgoing switch (14) is also connected to the load control cabinet (3) via a hard wire to receive control signals from the load control cabinet (3).

5. The overload prevention and control device for emergency power supply operation of multiple transformers as described in claim 4, characterized in that: The communication switch (16) is connected to the load control cabinet (3) via a hard wire.

6. The overload prevention device for emergency power supply operation of multiple transformers interconnected as described in any one of claims 2-4, characterized in that: The load control cabinet (3) includes a signal receiving device (31), a data analysis device (32), a load control transmitting device (33), and a control panel (34). The data analysis device (32) is connected to the signal receiving device (31), the load control transmitting device (33), and the control panel (34) respectively. The main incoming switch (12) and the first outgoing switch (14) are connected to the signal receiving device (31), and the first outgoing switch (14) and the tie switch (16) are connected to the load control transmitting device (33).

7. The overload prevention and control device for emergency power supply operation of multiple transformers as described in claim 6, characterized in that: When a transformer (11) in one or more power supply systems (1) fails, the load control cabinet (3) obtains the first power of each transformer, the second power of the first outgoing switch (14), and the status of the incoming main switch (12) at the previous moment, which is either energized or de-energized. It then judges the first power of the transformers (11) in all power supply systems (1). When the sum of the first power of the transformers (11) in all power supply systems (1) is less than the limited power of the remaining transformers (11), the load control cabinet (3) controls the tie switch (16) to close. When the sum of the first power of the transformers (11) in all power supply systems (1) is greater than the limited power of the remaining transformers (11), the load control cabinet (3) controls the first outgoing switch (14) in some or all power supply systems (1) to open and then controls the tie switch (16) to close.

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