Device for protecting bus in ring main unit

Abstract

The utility model provides a device for protecting a bus in a ring main unit. The device comprises a first protection circuit and a second protection circuit; a first port of the first protection circuit is connected with a first power supply, and a second port is connected with a first end of the bus; the first port of the second protection circuit is connected with the second power supply, and the second port is connected with the second end of the bus; a third port and a fourth port of the first protection circuit are respectively connected with a fourth port and a third port of the second protection circuit, and the first / second protection circuit responds to the detected overcurrent signal and / or grounding signal and outputs a first / second indication signal at the fourth port. The first protection circuit controls the second port to be disconnected from the bus in response to outputting the first indication signal and not receiving the second indication signal, and the second protection circuit controls the second port to be disconnected from the bus in response to outputting the second indication signal and not receiving the first indication signal. The device has the characteristics of simplicity, practicability, low cost, reliability and the like.

Description

Technical Field

[0001] The utility model relates to the field of protection circuits, and more specifically, to a device for protecting a busbar in a ring network cabinet. Background Art

[0002] The application of medium voltage ring network architecture is becoming more and more common in industries such as data centers and transportation infrastructure. In the medium voltage ring network architecture, one or more ring network cabinets are usually deployed between the main power supply and the backup power supply. At the same time, by setting the switch state (for example, open or closed) in the ring network cabinet, only one of the main power supply and the backup power supply can supply power to the load.

[0003] When a fault occurs in the cable between the ring main units, the device for line differential protection installed in the ring main unit can detect the fault and quickly cut off the corresponding switch to cut off the current flowing through the ring main unit, thereby protecting the electrical equipment in the ring main unit. Utility Model Content

[0004] In view of the above problems, the utility model provides a device for protecting the busbar in the ring network cabinet, which can use the overcurrent protection and / or grounding protection functions of the existing device for line differential protection in the ring network cabinet, and by properly connecting the above two devices for line differential protection, when the busbar sends a fault, the corresponding switch can be quickly cut off to cut off the current flowing through the busbar. The device for protecting the busbar in the ring network cabinet provided by the utility model has the characteristics of simplicity, practicality, low cost, etc.

[0005] The embodiment of the utility model provides a device for protecting a bus in a ring network cabinet, characterized in that the device includes a first protection circuit and a second protection circuit; the first port of the first protection circuit is connected to a first external power supply, and the second port is connected to the first end of the bus; the first port of the second protection circuit is connected to a second external power supply or another ring network cabinet, and the second port is connected to the second end of the bus; a load is connected between the first end and the second end of the bus; the third port of the first protection circuit is connected to the fourth port of the second protection circuit; the fourth port of the first protection circuit is connected to the third port of the second protection circuit, the first protection circuit outputs a first indication signal at its fourth port in response to detecting an overcurrent signal and / or a grounding signal, and the second protection circuit outputs a second indication signal at its fourth port in response to detecting an overcurrent signal and / or a grounding signal, characterized in that the first protection circuit controls the second port of the first protection circuit to be disconnected from the bus in response to outputting the first indication signal and not receiving the second indication signal at its third port, and the second protection circuit controls the second port of the second protection circuit to be disconnected from the bus in response to outputting the second indication signal and not receiving the first indication signal at its third port.

[0006] According to an embodiment of the utility model, it is characterized in that the first switch corresponding to the first protection circuit is connected between the second port of the first protection circuit and the first end of the bus, and the first protection circuit controls the second port of the first protection circuit to be disconnected from the bus in response to outputting the first indication signal and not receiving the second indication signal at its third port, including: in response to the first protection circuit outputting the first indication signal at its fourth port and not receiving the second indication signal at its third port, the first protection circuit outputs the first disconnection signal indicating the disconnection of the first switch at its fifth port; or the second switch corresponding to the second protection circuit is connected between the second port of the second protection circuit and the second end of the bus, and the second protection circuit controls the second port of the second protection circuit to be disconnected from the bus in response to outputting the second indication signal and not receiving the first indication signal at its third port, including: in response to the second protection circuit outputting the second indication signal at its fourth port and not receiving the first indication signal at its third port, the second protection circuit outputs the second disconnection signal indicating the disconnection of the second switch at its fifth port.

[0007] According to an embodiment of the utility model, it is characterized in that the device also includes a third protection circuit with overcurrent protection and / or grounding protection, the first port of the third protection circuit is connected between the first end and the second end of the bus, the second port is connected to the load, and the load is connected between the first end and the second end of the bus via the third protection circuit, and it is characterized in that the third port of the third protection circuit is connected to the third port of the first protection circuit, and the fourth port is connected to the third port of the second protection circuit, and the third protection circuit outputs a third indication signal at its third port and fourth port in response to detecting an overcurrent signal and / or a grounding signal, and in response to the third protection circuit outputting the third indication signal at its third port and fourth port, the third switch corresponding to the third protection circuit is disconnected to cut off the current flowing through the bus.

[0008] According to an embodiment of the utility model, it is characterized in that the first protection circuit includes a first AND gate circuit and a first indication signal generating circuit, the third port of the first protection circuit is connected to the first input port of the first AND gate circuit via a logic inversion circuit, the first indication signal generating circuit is connected to the second input port of the first AND gate circuit, the output port of the first AND gate circuit is connected to the fifth port of the first protection circuit, the first indication signal generating circuit outputs the first indication signal to the fourth port of the first protection circuit in response to detecting an overcurrent signal and / or a grounding signal, in response to the second input port of the first AND gate circuit receiving the first indication signal output by the first indication signal generating circuit to the second input port of the first AND gate circuit and the first input port of the first AND gate circuit not receiving the second indication signal after logic inversion via the third port of the first protection circuit, the output port of the first AND gate circuit outputs the first disconnect signal to the fifth port of the first protection circuit.

[0009] According to an embodiment of the present invention, the first protection circuit comprises a first delay circuit, and the output port of the first AND gate circuit is connected to the fifth port of the first protection circuit via the first delay circuit.

[0010] According to an embodiment of the utility model, it is characterized in that the second protection circuit includes a second AND gate circuit and a second indication signal generating circuit, the third port of the second protection circuit is connected to the first input port of the second AND gate circuit via a logic inversion circuit, the second indication signal generating circuit is connected to the second input port of the second AND gate circuit, the output port of the second AND gate circuit is connected to the fifth port of the second protection circuit, the second indication signal generating circuit outputs the second indication signal to the fourth port of the second protection circuit in response to detecting an overcurrent signal and / or a grounding signal, in response to the second input port of the second AND gate circuit receiving the second indication signal output by the second indication signal generating circuit to the second input port of the second AND gate circuit and the first input port of the second AND gate circuit not receiving the first indication signal after logic inversion via the third port of the second protection circuit, the output port of the second AND gate circuit outputs the second disconnect signal to the fifth port of the second protection circuit.

[0011] According to an embodiment of the present invention, the second protection circuit comprises a second delay circuit, and the output port of the second AND gate circuit is connected to the fifth port of the second protection circuit via the second delay circuit.

[0012] According to an embodiment of the utility model, it is characterized in that the third protection circuit includes a third AND gate circuit and a third indication signal generating circuit, the fifth port of the third protection circuit is connected to the first input port of the third AND gate circuit via a logic inversion circuit, the third indication signal generating circuit is connected to the second input port of the third AND gate circuit, the output port of the third AND gate circuit is connected to the sixth port of the third protection circuit, the third indication signal generating circuit outputs a third indication signal in response to detecting an overcurrent signal and / or a grounding signal, in response to the second input port of the third AND gate circuit receiving the third indication signal output by the third indication signal generating circuit and the first input port of the third AND gate circuit not receiving any signal input, the output port of the third AND gate circuit outputs a third disconnection signal to the sixth port of the third protection circuit, wherein the third disconnection signal is used to indicate that the third switch is disconnected.

[0013] According to an embodiment of the utility model, it is characterized in that the third protection circuit includes a third delay circuit, and the output port of the third AND gate circuit is connected to the sixth port of the third protection circuit via the third delay circuit.

[0014] According to an embodiment of the utility model, it is characterized in that at least one of the first switch, the second switch and the third switch is a circuit breaker.

[0015] The utility model provides the above-mentioned device for protecting the busbar in the ring network cabinet. The device provided by the utility model can use two protection circuits with overcurrent protection and / or grounding protection functions in the existing ring network cabinet. By properly connecting the above-mentioned two protection circuits, it can quickly cut off the corresponding switch when the busbar sends a fault to cut off the current flowing through the busbar. The device for protecting the busbar in the ring network cabinet provided by the utility model has the characteristics of simplicity, practicality, low cost, and reliability. In addition, the device for protecting the busbar in the ring network cabinet provided by the utility model uses the existing protection circuit, has no additional hardware cost, and does not require voltage / direction elements. In addition, the device for protecting the busbar in the ring network cabinet provided by the utility model can achieve rapid isolation of downstream faults due to the provision of a third protection circuit, so as to further protect the busbar. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solution of the embodiment of the utility model, the following is a brief introduction to the drawings required for the description of the embodiment. Obviously, the drawings described below are only some exemplary embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 A schematic diagram of an existing medium voltage ring network architecture 100 is shown;

[0018] Figure 2 A schematic diagram of a device 200 for protecting a busbar in a ring main unit according to an embodiment of the utility model is shown;

[0019] Figure 3 A schematic diagram showing the connection mode of two protection circuits and the internal circuit in a device 200 for protecting a busbar in a ring main unit according to an embodiment of the utility model is shown;

[0020] Figures 4 to 5 A schematic diagram showing a connection mode and an internal circuit of a third protection circuit in a device 200 for protecting a busbar in a ring main unit according to an embodiment of the utility model is shown;

[0021] Figures 6 to 8 A schematic diagram is shown of protecting a busbar in a ring main unit when a fault occurs according to the utility model. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution of the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings of the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the described embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0023] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one", "one" or "the" do not indicate quantity restrictions, but indicate the existence of at least one. Words such as "include" or "comprise" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0024] Currently, if Figure 1 As shown, Figure 1 FIG. 1 shows a schematic diagram of an existing medium voltage ring network architecture 100. Figure 1 3. The figure shows three ring main units, namely, ring main unit 1 (RMU-1), ring main unit 2 (RMU-2) and ring main unit 3 (RMU-3). Ring main unit 1 is connected to an external power source 1, and ring main unit 3 is connected to another external power source 2.

[0025] like Figure 1 As shown, protection circuits for line differential protection are deployed between adjacent ring network cabinets. For example, protection circuits P-11 and P-12 are deployed in ring network cabinet 1, protection circuits P-21 and P-22 are deployed in ring network cabinet 2, and protection circuits P-31 and P-32 are deployed in ring network cabinet 3. The protection circuits of adjacent ring network cabinets (such as between P-12 and P21, between P-22 and P-31) are connected through optical fiber channels to perform line differential protection by exchanging information such as current and voltage.

[0026] like Figure 1As shown, each protection circuit has a corresponding switch, for example, protection circuit P-11 corresponds to switch A1, protection circuit P-12 corresponds to switch B1, protection circuit P-21 corresponds to switch A2, protection circuit P-22 corresponds to switch B2, protection circuit P-31 corresponds to switch A3, and protection circuit P-32 corresponds to switch B3.

[0027] like Figure 1 As shown, at the same time, at least one of the above switches is normally open. For example, switch A3 can be set to be normally open (NOP) according to actual needs. In this way, at the same time, only one of power supply 1 and power supply 2 supplies power to the load.

[0028] exist Figure 1 In the figure, the thick line BUS1 in the ring main unit 1, the thick line BUS2 in the ring main unit 2 and the thick line BUS3 in the ring main unit 3 are the busbars in the corresponding ring main units.

[0029] like Figure 1 As shown, assuming that power supply 1 is the main power supply at this time, the main power supply passes through the protection circuit P-11 and switch A1, and then supplies power to load 1 through the bus in ring main unit 1 (for example, through a transformer), and then supplies power to ring main unit 2 through switch B1 and protection circuit P-12. The supplied power passes through the protection circuit P-21 and switch A2 in ring main unit 2, and then supplies power to load 2 through the bus in ring main unit 2 (for example, through a transformer), and then supplies power to ring main unit 3 through switch B2 and protection circuit P-22. Since switch A3 in the ring main unit is normally open, the power supply terminates at ring main unit 3.

[0030] When the cable between the ring main units fails (such as Figure 1 The lightning mark in the figure shows that after the protection circuits P-12 and P-21 for line differential protection exchange relevant information, their corresponding switches (i.e., B1 and A2) are controlled to open respectively to cut off the fault.

[0031] However, when a busbar BUS1 in the ring main unit 1, a busbar BUS2 in the ring main unit 2, or a busbar BUS3 in the ring main unit 3 fails, the above protection circuit cannot detect the fault, and thus cannot cut off the fault to protect the busbar. In this case, the existing solution is often to purchase a dedicated busbar protection device, which is expensive and complex to implement (for example, it often needs to be interlocked based on the Goose communication protocol).

[0032] In order to solve the above problems, the utility model provides a device for protecting the busbar in the ring network cabinet. The device can use the overcurrent protection and / or grounding protection functions in the existing device for line differential protection in the ring network cabinet, and by properly connecting the above two devices for line differential protection, it is possible to quickly cut off the corresponding switch when the busbar sends a fault, thereby cutting off the current flowing through the busbar. The device for protecting the busbar in the ring network cabinet provided by the utility model has the characteristics of simplicity, practicality, low cost, etc.

[0033] Now, the device for protecting the busbar in the ring network cabinet provided by the utility model will be described in detail with reference to the accompanying drawings.

[0034] Figure 2 A schematic diagram of a device 200 for protecting a busbar in a ring main unit according to an embodiment of the utility model is shown.

[0035] Reference Figure 2 , the device 200 may include a first protection circuit (such as P-11 above) and a second protection circuit (such as P-12 above). The device 200 may include a first switch (such as A1 above) corresponding to the first protection circuit and a second switch (such as B1 above) corresponding to the second protection circuit. The first switch and the second switch may be any suitable switches, such as a circuit breaker. The first switch and the first protection circuit may be separately set as different components, or may be integrated as the same component. The second switch and the second protection circuit may be separately set as different components, or may be integrated as the same component.

[0036] Reference Figure 2 The first port of the first protection circuit is connected to a first external power supply (such as power supply 1), and the second port is connected to a first end 1 of the bus (such as bus BUS1); the first port of the second protection circuit is connected to a second external power supply (such as power supply 2) or another ring network cabinet (such as RMU-2), and the second port is connected to a second end 2 of the bus; a load (such as load 1) is connected between the first end 1 and the second end 2 of the bus.

[0037] The first protection circuit and the second protection circuit can be connected to each other through hard wiring to exchange information. This hard wiring connection method is not limited by communication and has simple logic and is easy to debug. Specifically, the connection method of the first protection circuit and the second protection circuit can be as follows: Figure 3As shown. The third port 3 (INPUT|BLOCK) of the first protection circuit is connected to the fourth port 4 (OCEF START) of the second protection circuit; the fourth port 4 (OCEF START) of the first protection circuit is connected to the third port 3 (INPUT|BLOCK) of the second protection circuit, the first protection circuit outputs a first indication signal at its fourth port 4 in response to detecting an overcurrent signal and / or a grounding signal, and the second protection circuit outputs a second indication signal at its fourth port 4 in response to detecting an overcurrent signal and / or a grounding signal. Note that the first protection circuit and the second protection circuit used in the present invention only need to have at least one of the overcurrent protection and grounding protection functions, for example, the above combination Figure 1 The protection circuit for line differential protection generally has an overcurrent protection function and / or a grounding protection function. In other words, the first protection circuit and the second protection circuit used in the utility model can use existing protection circuits, and the busbar can be protected by properly connecting the two protection circuits.

[0038] According to an embodiment of the utility model, the first protection circuit in the device 200 is capable of controlling the second port of the first protection circuit to be disconnected from the bus in response to outputting the first indication signal and not receiving the second indication signal at its third port 3 to cut off the current flowing through the bus; and the second protection circuit is capable of controlling the second port of the second protection circuit to be disconnected from the bus in response to outputting the second indication signal and not receiving the first indication signal at its third port 3 to cut off the current flowing through the bus.

[0039] Depend on Figure 3 As can be seen from the connection mode shown, the first indication signal of the first protection circuit can be input to the second protection circuit without delay, and the second indication signal of the second protection circuit can be input to the first protection circuit without delay, so that mutual interlocking can be achieved when the ring main unit fails externally. Figure 7 The contents described will not be repeated here.

[0040] According to an embodiment of the utility model, the first switch corresponding to the first protection circuit (such as the combination of Figure 2A1) described above is connected between the second port of the first protection circuit and the first end 1 of the bus, and the first protection circuit controls the second port of the first protection circuit to be disconnected from the bus in response to outputting the first indication signal and not receiving the second indication signal at its third port 3, including: in response to the first protection circuit outputting the first indication signal at its fourth port 4 and not receiving the second indication signal at its third port 3, the first protection circuit outputs the first disconnection signal indicating the first switch (such as A1) to be disconnected at its fifth port 5 (TRIP CB A) so that the first switch (such as A1) is disconnected.

[0041] According to an embodiment of the utility model, a second switch corresponding to the second protection circuit (such as B1 mentioned above) is connected between the second port of the second protection circuit and the second end 2 of the busbar, and the second protection circuit controls the second port of the second protection circuit to be disconnected from the busbar in response to outputting the second indication signal and not receiving the first indication signal at its third port 3, including: in response to the second protection circuit outputting the second indication signal at its fourth port 4 and not receiving the first indication signal at its third port 3, the second protection circuit outputs a second disconnection signal at its fifth port 5 (TRIP CB B) indicating that the second switch (such as B1 mentioned above) is disconnected, so that the second switch (such as B1 mentioned above) is disconnected.

[0042] According to the embodiment of the utility model, Figure 3 As shown, the first protection circuit may include a first AND gate circuit AND1 and a first indication signal generating circuit OCEF1. The third port 3 of the first protection circuit is connected to the first input port 1 of the first AND gate circuit AND1 via a logic negation circuit (as indicated by the circle ○ in 3), the first indication signal generating circuit OCEF is connected to the second input port 2 of the first AND gate circuit AND1, and the output port 3 of the first AND gate circuit AND1 is connected to the fifth port 5 of the first protection circuit. Figure 3 The delay circuit Td1 shown by the dotted line is an optional circuit, which will be described below and will not be repeated here. The first indication signal generating circuit OCEF1 outputs a first indication signal to the fourth port 4 of the first protection circuit in response to detecting an overcurrent signal and / or a grounding signal. In response to the second input port 2 of the first AND gate circuit AND1 receiving the first indication signal output by the first indication signal generating circuit OCEF1 to the second input port 2 of the first AND gate circuit AND1 and the first input port 1 of the first AND gate circuit AND1 not receiving the second indication signal after logical inversion via the third port 3 of the first protection circuit, the output port 3 of the first AND gate circuit AND1 directly outputs a first disconnection signal to the fifth port 5 of the first protection circuit.

[0043] According to the embodiment of the utility model, Figure 3 As shown, the first protection circuit may include a first delay circuit Td1, and the output port 3 of the first AND gate circuit AND1 is connected to the fifth port 5 of the first protection circuit via the first delay circuit Td1. Those skilled in the art may set a specific value of the delay circuit Td1 based on actual needs, for example, setting a delay value of 0.005 milliseconds, which means that the signal output from the output port 3 of the first AND gate circuit AND1 is delayed by 0.005 milliseconds before being output to the fifth port 5.

[0044] According to the embodiment of the utility model, Figure 3 As shown, the second protection circuit may include a second AND gate circuit AND2 and a second indication signal generating circuit OCEF2. The third port 3 of the second protection circuit is connected to the first input port 1 of the second AND gate circuit AND2 via a logic negation circuit (as shown by the circle ○ in 3), the second indication signal generating circuit OCEF2 is connected to the second input port 2 of the second AND gate circuit AND2, and the output port 3 of the second AND gate circuit AND2 is connected to the fifth port 5 of the second protection circuit. Figure 3 The delay circuit Td2 shown by the dotted line is an optional circuit, which will be described below and will not be repeated here. The second indication signal generating circuit OCEF2 outputs a second indication signal to the fourth port 4 of the second protection circuit in response to detecting an overcurrent signal and / or a grounding signal. In response to the second input port 2 of the second AND gate circuit AND2 receiving the second indication signal output by the second indication signal generating circuit OCEF2 to the second input port 2 of the second AND gate circuit AND2 and the first input port 1 of the second AND gate circuit AND2 not receiving the first indication signal after logical inversion via the third port 3 of the second protection circuit, the output port 3 of the second AND gate circuit AND2 directly outputs a second disconnection signal to the fifth port 5 of the second protection circuit.

[0045] According to the embodiment of the utility model, Figure 3 As shown, the second protection circuit may include a second delay circuit Td2, and the output port 3 of the second AND gate circuit AND2 is connected to the fifth port 5 of the second protection circuit via the second delay circuit Td2. Those skilled in the art may set a specific value of the delay circuit Td2 based on actual needs, for example, setting a delay value of 0.001 milliseconds, which means that the signal output from the output port 3 of the second AND gate circuit AND2 is delayed by 0.001 milliseconds before being output to the fifth port 5.

[0046] According to the embodiment of the utility model, Figure 4 As shown, the device 200 may also include a third protection circuit (such as Figure 4The first port of the third protection circuit is connected between the first end 1 and the second end 2 of the bus, and the second port is connected to the load (such as Figure 4 The load 1 or the load 2 or the load 3 shown in the figure is connected between the first end 1 and the second end 2 of the busbar via the third protection circuit.

[0047] The third protection circuit can be connected to the first protection circuit and the second protection circuit by hard wiring. This hard wiring connection method is not limited by communication and has simple logic and is easy to debug. As an example, Figure 5 As shown, the third port 3 (OCEF START) of the third protection circuit is connected to the third port 3 of the first protection circuit, and the fourth port 4 (OCEF START) is connected to the third port 3 of the second protection circuit. In response to detecting an overcurrent signal and / or a grounding signal, the third protection circuit outputs a third indication signal at its third port 3 and fourth port 4. In response to the third protection circuit outputting the third indication signal at its third port 3 and fourth port 4, a third switch (such as Figure 4 The switch C1 or C2 or C3 shown in FIG. 1 is opened to cut off the current flowing through the bus. The third switch can be any suitable switch, such as a circuit breaker.

[0048] According to the embodiment of the utility model, Figure 5 As shown, the third protection circuit may include a third AND gate circuit AND2 and a third indication signal generating circuit OCEF3, a fifth port 5 (INPUT|BLOCK) of the third protection circuit is connected to a first input port 1 of the third AND gate circuit AND3 via a logic negation circuit, the third indication signal generating circuit OCEF3 is connected to a second input port 2 of the third AND gate circuit AND3, and an output port 3 of the third AND gate circuit AND3 is connected to a sixth port 6 (TRIP CB C) of the third protection circuit. Figure 5 The delay circuit Td3 shown by the dashed line is an optional circuit, which will be described below and will not be repeated here.

[0049] The third indication signal generating circuit OCEF3 outputs a third indication signal in response to detecting an overcurrent signal and / or a grounding signal. In response to the second input port 2 of the third AND gate circuit AND3 receiving the third indication signal output by the third indication signal generating circuit OCEF3 and the first input port 1 of the third AND gate circuit AND3 not receiving any signal input, the output port 3 of the third AND gate circuit AND3 outputs a third disconnection signal to the sixth port 6 of the third protection circuit, wherein the third disconnection signal is used to instruct the third switch (such as Figure 4 The switch C1 or C2 or C3 shown in FIG. 1 is opened to cut off the current flowing through the bus.

[0050] According to an embodiment of the utility model, the third protection circuit may include a third delay circuit Td3, and the output port 3 of the third AND gate circuit AND3 is connected to the sixth port 6 of the third protection circuit via the third delay circuit Td3. Those skilled in the art may set a specific value of the delay circuit Td3 based on actual needs, for example, setting a delay value of 0.0003 milliseconds, which means that the signal output from the output port 3 of the third AND gate circuit AND3 is delayed by 0.0003 milliseconds before being output to the sixth port 6.

[0051] By combining the above Figure 5 As can be seen from the connection mode shown, the third indication signal of the third protection circuit can be input to the first protection circuit and the second protection circuit with zero delay, so that the first protection circuit and the second protection circuit can be locked when a downstream fault occurs. Figure 8 The contents described will not be repeated here.

[0052] Note that the third protection circuit used in the present invention only needs to have at least one of the overcurrent protection and grounding protection functions, for example, the above combination Figure 1 The protection circuit for line differential protection generally has an overcurrent protection function and / or a grounding protection function. In other words, the third protection circuit used in the present invention can use an existing protection circuit, and the busbar can be further protected by properly connecting the protection circuit with the first protection circuit and the second protection circuit.

[0053] The above combination Figures 1 to 5The device for protecting the busbar in the ring network cabinet provided by the utility model has been described in detail. From the above description, it can be seen that the device provided by the utility model can use the two protection circuits with overcurrent protection and / or grounding protection functions in the existing ring network cabinet. By properly connecting the above two protection circuits, it can quickly cut off the corresponding switch when the busbar sends a fault to cut off the current flowing through the busbar. The device for protecting the busbar in the ring network cabinet provided by the utility model has the characteristics of simplicity, practicality, low cost, and reliability. In addition, the device for protecting the busbar in the ring network cabinet provided by the utility model uses the existing protection circuit, has no additional hardware cost, and does not require voltage / direction elements.

[0054] In order to make the device for protecting the busbar in the ring main unit provided by the present invention clearer, the device for protecting the busbar in the ring main unit provided by the present invention will be further described in the form of examples.

[0055] Figures 6 to 8 A schematic diagram is shown of protecting a busbar in a ring main unit when a fault occurs according to the utility model. Figures 6 to 8 The examples are all performed in the following scenario: power supply 1 is the main power supply to supply power to the load, and switch A3 is in the normally open state.

[0056] Reference Figure 6 , when the busbar internal fault occurs (such as Figure 6 As shown by the lightning point F1 in the figure, the first protection circuit P-11 with overcurrent protection and / or grounding protection function detects the overcurrent signal and / or grounding signal, thereby outputting the first indication signal at its fourth port; while the second protection circuit P-12 and the third protection circuit P-13 with overcurrent protection and / or grounding protection function will not detect the overcurrent signal and / or grounding signal, thereby will not output the corresponding indication signal (such as the second indication signal and the third indication signal mentioned above). In the above case, the first indication signal output by the first protection circuit to the second protection circuit causes the second protection circuit to lock (that is, the second protection circuit will not output the second disconnection signal); and the second protection circuit will not output the second indication signal to the first protection circuit (that is, the first protection circuit has no locking signal), thereby causing the first protection circuit to output the first disconnection signal at its fifth port, thereby causing the first switch (such as A1) to trip (that is, disconnect), thereby quickly isolating the fault.

[0057] Reference Figure 7 , when the busbar has an external fault (such as Figure 7As shown by the F2 lightning point in the figure), the first protection circuit P-11 and the second protection circuit P-12 with overcurrent protection and / or grounding protection function will both detect the overcurrent signal and / or the grounding signal, and thus both output indication signals (such as the first indication signal and the second indication signal mentioned above) at their fourth ports; and the third protection circuit P-13 with overcurrent protection and / or grounding protection function will not detect the overcurrent signal and / or the grounding signal, and thus will not output the corresponding indication signal (such as the third indication signal mentioned above). In the above case, the first indication signal output by the first protection circuit to the second protection circuit causes the second protection circuit to be locked (that is, the second protection circuit will not output the second disconnection signal) and the second indication signal output by the second protection circuit to the first protection circuit causes the first protection circuit to be locked (that is, the first protection circuit will not output the first disconnection signal). In this case, based on the existing protection circuit for line differential protection, the switches on both sides of the fault point can be quickly disconnected, thereby quickly isolating the fault; for example, assuming that the protection circuit in the device provided by the utility model is an existing protection circuit for line differential protection, the line differential protection function of the protection circuit can be used to quickly isolate the fault.

[0058] Reference Figure 8 , when a downstream fault occurs (such as Figure 8 As shown by the F3 lightning point in the figure), assuming that the third protection circuit mentioned above does not exist at this time, but other protection circuits for downstream fault detection and processing already exist in the ring main unit in advance, a suitable delay value can be set for the first delay circuit in the first protection circuit based on the actual application scenario. In this case, both the first protection circuit and the other protection circuit detect the overcurrent signal and / or the grounding signal, while the second protection circuit does not detect the overcurrent signal and / or the grounding signal. Since the first protection circuit is set with a suitable delay value, the other protection circuit will first trigger the corresponding switch to disconnect. Since the first protection circuit will no longer detect the overcurrent signal and / or the grounding signal after the disconnection, the first protection circuit will not send out a disconnection signal again.

[0059] Continue to refer to Figure 8 , when a downstream fault occurs (such as Figure 8), assuming that the third protection circuit exists. The first protection circuit P-11 and the third protection circuit P-13 with overcurrent protection and / or grounding protection functions both detect overcurrent signals and / or grounding signals, and the second protection circuit P-12 does not detect overcurrent signals and / or grounding signals, so that the first protection circuit outputs a first indication signal at its fourth port and the third protection circuit outputs a third indication signal at its third and fourth ports. In the above case, the third indication signal output by the third protection circuit to the first protection circuit and the second protection circuit causes both the first protection circuit and the second protection circuit to be locked (i.e., the first protection circuit does not output the first disconnection signal and the second protection circuit does not output the second disconnection signal), so that the first switch corresponding to the first protection circuit and the second switch corresponding to the second protection circuit will not be disconnected. At this time, the third switch corresponding to the third protection circuit will quickly act to trip (i.e., disconnect), thereby quickly isolating the fault.

[0060] The block diagrams of the circuits, units, devices, apparatuses, equipment, and systems involved in the present utility model are only illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As will be appreciated by those skilled in the art, these circuits, units, devices, apparatuses, equipment, and systems may be connected, arranged, and configured in any manner as long as the desired purpose can be achieved. The circuits, units, devices, and apparatuses involved in the present utility model may be implemented in any suitable manner, such as using a dedicated integrated circuit, a field programmable gate array (FPGA), and the like.

[0061] Those skilled in the art should understand that the above-mentioned specific embodiments are merely examples and not limitations, and various modifications, combinations, partial combinations and replacements may be made to the embodiments of the utility model according to design requirements and other factors. As long as they are within the scope of the attached claims or their equivalents, they belong to the scope of rights to be protected by the utility model.

Claims

1. A device for protecting a busbar in a ring main unit, characterized in that: The device includes a first protection circuit and a second protection circuit; The first port of the first protection circuit is connected to the first external power supply, and the second port is connected to the first end of the busbar; The first port of the second protection circuit is connected to a second external power source or another ring main unit, and the second port is connected to the second end of the busbar; A load is connected between the first end and the second end of the busbar; The third port of the first protection circuit is connected to the fourth port of the second protection circuit, and the fourth port is connected to the third port of the second protection circuit. The first protection circuit outputs a first indication signal at its fourth port in response to detecting an overcurrent signal and / or a grounding signal, and the second protection circuit outputs a second indication signal at its fourth port in response to detecting an overcurrent signal and / or a grounding signal. In response to outputting the first indication signal and not receiving the second indication signal at its third port, the first protection circuit controls the second port of the first protection circuit to be disconnected from the bus, and In response to the second protection circuit outputting the second indication signal and not receiving the first indication signal at the third port thereof, the second protection circuit controls the second port of the second protection circuit to be disconnected from the bus.

2. The device according to claim 1, characterized in that A first switch corresponding to the first protection circuit is connected between the second port of the first protection circuit and the first end of the bus, and the first protection circuit controls the second port of the first protection circuit to be disconnected from the bus in response to outputting the first indication signal and not receiving the second indication signal at its third port, including: In response to the first protection circuit outputting the first indication signal at its fourth port and not receiving the second indication signal at its third port, the first protection circuit outputting a first disconnection signal at its fifth port indicating disconnection of the first switch; or A second switch corresponding to the second protection circuit is connected between the second port of the second protection circuit and the second end of the bus, and the second protection circuit controls the second port of the second protection circuit to be disconnected from the bus in response to outputting the second indication signal and not receiving the first indication signal at its third port, including: In response to the second protection circuit outputting the second indication signal at its fourth port and not receiving the first indication signal at its third port, the second protection circuit outputs a second disconnection signal at its fifth port indicating disconnection of the second switch.

3. The device according to claim 1 or 2, characterized in that: The device further comprises a third protection circuit with overcurrent protection and / or ground protection, wherein a first port of the third protection circuit is connected between the first end and the second end of the bus, and a second port is connected to the load, and the load is connected between the first end and the second end of the bus via the third protection circuit. The third port of the third protection circuit is connected to the third port of the first protection circuit, and the fourth port is connected to the third port of the second protection circuit. In response to detecting an overcurrent signal and / or a grounding signal, the third protection circuit outputs a third indication signal at its third port and fourth port. In response to the third protection circuit outputting the third indication signal at its third port and fourth port, the third switch corresponding to the third protection circuit is disconnected to cut off the current flowing through the bus.

4. The device according to claim 2, characterized in that The first protection circuit includes a first AND gate circuit and a first indication signal generating circuit, wherein a third port of the first protection circuit is connected to a first input port of the first AND gate circuit via a logic negation circuit, the first indication signal generating circuit is connected to a second input port of the first AND gate circuit, and an output port of the first AND gate circuit is connected to a fifth port of the first protection circuit. The first indication signal generating circuit outputs the first indication signal to the fourth port of the first protection circuit in response to detecting the overcurrent signal and / or the ground signal. In response to the second input port of the first AND gate circuit receiving the first indication signal output by the first indication signal generating circuit to the second input port of the first AND gate circuit and the first input port of the first AND gate circuit not receiving the second indication signal after logical inversion via the third port of the first protection circuit, the output port of the first AND gate circuit outputs the first disconnect signal to the fifth port of the first protection circuit.

5. The device according to claim 4, characterized in that The first protection circuit includes a first delay circuit, and the output port of the first AND gate circuit is connected to the fifth port of the first protection circuit via the first delay circuit.

6. The device according to claim 2, characterized in that The second protection circuit includes a second AND gate circuit and a second indication signal generating circuit, the third port of the second protection circuit is connected to the first input port of the second AND gate circuit via a logic negation circuit, the second indication signal generating circuit is connected to the second input port of the second AND gate circuit, and the output port of the second AND gate circuit is connected to the fifth port of the second protection circuit. The second indication signal generating circuit outputs the second indication signal to the fourth port of the second protection circuit in response to detecting the overcurrent signal and / or the ground signal. In response to the second input port of the second AND gate circuit receiving the second indication signal output by the second indication signal generating circuit to the second input port of the second AND gate circuit and the first input port of the second AND gate circuit not receiving the first indication signal after logical inversion via the third port of the second protection circuit, the output port of the second AND gate circuit outputs the second disconnect signal to the fifth port of the second protection circuit.

7. The device according to claim 6, characterized in that The second protection circuit includes a second delay circuit, and the output port of the second AND gate circuit is connected to the fifth port of the second protection circuit via the second delay circuit.

8. The device according to claim 3, characterized in that The third protection circuit comprises a third AND gate circuit and a third indication signal generating circuit, wherein a fifth port of the third protection circuit is connected to a first input port of the third AND gate circuit via a logic negation circuit, the third indication signal generating circuit is connected to a second input port of the third AND gate circuit, and an output port of the third AND gate circuit is connected to a sixth port of the third protection circuit. The third indication signal generating circuit outputs a third indication signal in response to detecting an overcurrent signal and / or a ground signal, In response to the second input port of the third AND gate circuit receiving the third indication signal output by the third indication signal generating circuit and the first input port of the third AND gate circuit not receiving any signal input, the output port of the third AND gate circuit outputs a third disconnection signal to the sixth port of the third protection circuit, wherein the third disconnection signal is used to indicate that the third switch is disconnected.

9. The device according to claim 8, characterized in that The third protection circuit includes a third delay circuit, and the output port of the third AND gate circuit is connected to the sixth port of the third protection circuit via the third delay circuit.

10. The device according to any one of claims 1-2 and 4-9, characterized in that: At least one of the first switch, the second switch, and the third switch is a circuit breaker.

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