Ship direct current looped network system and selective short circuit protection method of its bus tie switch

Abstract

The application discloses a ship direct-current ring network system, comprising a direct-current main distribution board and a test distribution board, and bus coupler switches A-D are connected through cables to form a ring network; the application also discloses a selective short-circuit protection method for the bus coupler switches, when a short-circuit fault occurs in the bus of the ship direct-current ring network system, the transient current value and the current direction output by the solid-state switch in the bus coupler switch cabinet are collected in real time through the current high-speed sampling unit in the bus coupler switch controller, information is exchanged with the adjacent bus coupler switch controller by using the optical fiber communication mode, and the selective protection is carried out quickly in response to the short circuit according to the comprehensive judgment of the current direction, the current rising rate di / dt and the overcurrent protection, so that the response is executed before the overcurrent protection of the solid-state switch, and the reliable operation is ensured to avoid the false protection.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of ship power control technology, and particularly relates to a ship direct current looped network system and a selective short-circuit protection method for a bus tie switch thereof. BACKGROUND

[0002] It is an inevitable trend for the ship industry to implement green environmental protection and energy saving and emission reduction. Electric ships with direct current networking and electric propulsion as cores are more and more favored by the shipping industry due to their low / zero emission, easy intelligent control and high reliability.

[0003] However, once a short-circuit fault occurs in the ship direct current looped network system, the direct current bus voltage is rapidly reduced to cause fault protection, and the devices in the system cannot work. The mechanical circuit breaker protection has a long action time, the power electronic device current change rate is abnormal to perform fault processing, and the non-fault point of the direct current looped network bus tie has false protection. Therefore, the selective short-circuit protection device and method for the ship direct current looped network bus tie switch become a research focus, and play a crucial role in the safety and reliability of the whole ship operation. SUMMARY

[0004] One of the purposes of the present application is to provide a ship direct current looped network system to solve the technical problems of existing direct current bus short-circuit breaking not timely, non-fault point false action protection and poor reliability.

[0005] The technical scheme adopted by the present application to solve its technical problems is: a ship direct current looped network system, comprising a direct current main distribution board, a test distribution board, and a generator set, a generator rectifier unit, an inverter power unit, a main push inverter unit, a side push inverter unit, a bow and stern propulsion inverter unit, a DC / DC unit, a DC bus, a bus coupler switch module, a pre-charging module, etc. connected with the direct current main distribution board and the test distribution board respectively; the direct current main distribution board comprises a left side direct current main distribution board and a right side direct current main distribution board, the left side direct current main distribution board is connected with a 4000A bus coupler switch A and a 2000A bus coupler switch C at two ends respectively, the right side direct current main distribution board is connected with a 4000A bus coupler switch B and a 2000A bus coupler switch D at two ends respectively, the bus coupler switch A and the bus coupler switch B are connected through a cable, the bus coupler switch C and the bus coupler switch D are connected at two ends of the test distribution board through a cable; the bus coupler switch A and the bus coupler switch B are composed of a bus coupler switch controller and ten solid state switch modules arranged in a 4000A bus coupler switch cabinet one, the bus coupler switch C and the bus coupler switch D are composed of a bus coupler switch controller and five solid state switch modules arranged in a 2000A bus coupler switch cabinet two, each solid state switch module is connected with a module controller, two 4000A bus coupler switch cabinets one and two 2000A bus coupler switch cabinets two form a looped network structure, the bus coupler switch controllers in adjacent two pre-charging modules exchange current direction information through an optical fiber, a short circuit protection enable signal is sent to a first solid state switch module controller in the bus coupler switch cabinet one or the bus coupler switch cabinet two, the module controller forwards the short circuit protection enable signal to a second solid state switch module controller, the second solid state switch module controller forwards the short circuit protection enable signal to a third solid state switch module controller, and the last solid state switch module controller uploads the bus coupler switch current direction information in the bus coupler switch cabinet one or the bus coupler switch cabinet two to the bus coupler switch controller.

[0006] The second object of the present application is to provide a ship direct current looped network bus coupler switch selective short circuit protection method, comprising the following steps:

[0007] S101, after the bus coupler switches A-D are closed, the module controller outputs the current direction, and exchanges information with the adjacent bus coupler switch controller through an optical fiber;

[0008] S102, the current direction of the adjacent bus coupler switch controller is collected in real time through an optical fiber, when the current direction of the bus coupler switch controller is the same as the current direction of the adjacent bus coupler switch controller and the current rising rate di / dt exceeds the protection value, the bus coupler switch controller is enabled for short circuit protection; otherwise, it is prohibited;

[0009] S103, an enable signal is sent to the module controller of the solid state switch in real time, and the module controller executes the di / dt protection and overcurrent protection functions;

[0010] S104, after the solid-state switch is turned off, the fault current direction is latched, real-time information is uploaded to the bus tie switch controller, and is transmitted to the adjacent bus tie switch controller through optical fiber to ensure that the adjacent bus tie switch controller can correctly enable the bus tie switch short circuit protection.

[0011] Further, if the current direction of bus tie switch A is negative, the current direction of bus tie switch B is negative, the current direction of bus tie switch C is positive, the current direction of bus tie switch D is positive or negative, the bus tie switch A and the bus tie switch C are protected, and the bus tie switch B and the bus tie switch D are normally operated, it is judged that the short circuit point is the left side DC main distribution board; if the current direction of bus tie switch A is positive, the current direction of bus tie switch B is negative, the current direction of bus tie switch C is positive, and the current direction of bus tie switch D is negative, the bus tie switch A and the bus tie switch B are protected, and the bus tie switch C and the bus tie switch D are normally operated, it is judged that the short circuit point is between the bus tie switch A and the bus tie switch B of 4000A; if the current direction of bus tie switch A is positive, the current direction of bus tie switch B is positive, the current direction of bus tie switch C is positive or negative, the current direction of bus tie switch D is negative, the bus tie switch B and the bus tie switch D are protected, and the bus tie switch A and the bus tie switch C are normally operated, it is judged that the short circuit point is between the right side 2000A bus tie switch C and the test distribution board; if the current direction of bus tie switch A is negative, the current direction of bus tie switch B is positive or negative, the current direction of bus tie switch C is negative, the current direction of bus tie switch D is positive, the bus tie switch C and the bus tie switch D are protected, and the bus tie switch A and the bus tie switch B are normally operated, it is judged that the short circuit point is between the left side 2000A bus tie switch C and the test distribution board; if the current direction of bus tie switch A is positive or negative, the current direction of bus tie switch B is positive or negative, the current direction of bus tie switch C is negative, the current direction of bus tie switch D is positive, the bus tie switch C and the bus tie switch D are protected, and the bus tie switch A and the bus tie switch B are normally operated, it is judged that the short circuit point is the test distribution board; if the current direction of bus tie switch A is positive or negative, the current direction of bus tie switch B is positive, the current direction of bus tie switch C is negative, the current direction of bus tie switch D is positive, the bus tie switch C and the bus tie switch D are protected, and the bus tie switch A and the bus tie switch B are normally operated, it is judged that the short circuit point is between the right side 2000A bus tie switch D and the test distribution board.

[0012] Further, the bus tie switch A short circuit protection is enabled when the current of bus tie switch A is positive and the current of bus tie switch B is negative or the current of bus tie switch A is negative and the current of bus tie switch C is positive; the bus tie switch B short circuit protection is enabled when the current of bus tie switch B is positive and the current of bus tie switch D is negative or the current of bus tie switch B is negative and the current of bus tie switch A is positive; the bus tie switch C short circuit protection is enabled when the current of bus tie switch C is positive and the current of bus tie switch A is negative or the current of bus tie switch C is negative and the current of bus tie switch D is positive; the bus tie switch D short circuit protection is enabled when the current of bus tie switch D is positive and the current of bus tie switch C is negative or the current of bus tie switch D is negative and the current of bus tie switch B is positive.

[0013] Further, the bus tie switch controller is placed in the pre-charge module.

[0014] The beneficial effects of the present application are: when the bus of the ship DC looped network system has a short circuit fault, the current high-speed sampling unit in the bus coupler bus coupler controller collects the solid state switch output transient current value and current direction in real time, uses the optical fiber communication mode to interact information with the adjacent bus coupler, if the current direction of the bus coupler and the current direction of the adjacent bus coupler are opposite, and the current rising rate di / dt exceeds the protection value, the bus coupler short circuit protection function is enabled, otherwise it is prohibited. The present application comprehensively judges according to the current direction, current rising rate di / dt, overcurrent protection and other methods, and when a short circuit occurs, it should be able to respond quickly to selective protection, ensure that the response is executed before the overcurrent protection of the solid state switch, and when no short circuit occurs, it should be able to operate reliably, avoiding false protection. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is a single line schematic diagram of the ship DC looped network system of the present application;

[0016] Figure 2 It is a short circuit schematic diagram of the ship DC looped network system of the present application;

[0017] Figure 3 It is a bus coupler selective short circuit protection flow chart of the ship DC looped network system of the present application;

[0018] Figure 4 It is a bus coupler selective short circuit protection scheme diagram of the ship DC looped network system of the present application.

[0019] The reference signs are: 1-left side DC main distribution board, 2-right side DC main distribution board, 3-test distribution board, 4-cable. DETAILED DESCRIPTION

[0020] The embodiments of the present application are described in detail below with reference to the accompanying drawings. Among them, the drawings constitute a part of the present application, and together with the embodiments of the present application, they are used to illustrate the principles of the present application, and are not used to limit the scope of the present application.

[0021] As Figure 1As shown, the ship DC ring network system disclosed by the application comprises a DC main distribution board and a test distribution board 3, and a generator set, a generator rectifier unit, an inverter power supply unit, a main push inverter unit, a side push inverter unit, a bow and stern propulsion inverter unit, a DC / DC unit, a DC bus, a bus tie switch module, a pre-charging module and the like connected with the DC main distribution board and the test distribution board 3 respectively; the DC main distribution board comprises a left side DC main distribution board 1 and a right side DC main distribution board 2, the left side DC main distribution board 1 is connected with a 4000A bus tie switch A and a 2000A bus tie switch C at two ends respectively, the right side DC main distribution board 2 is connected with a 4000A bus tie switch B and a 2000A bus tie switch D at two ends respectively, the bus tie switch A and the bus tie switch B are connected through a cable 4, and the bus tie switch C and the bus tie switch D are connected at two ends of the test distribution board 3 through the cable 4.

[0022] The generator set is set as a short circuit point F1, a short circuit point between the power module and the fuse is set as a short circuit point F2, the generator rectifier unit, the inverter power supply unit, the main push inverter unit, the side push inverter unit and the DC / DC unit are fused and protected through the fuse, and meanwhile, the 4000A bus tie switch and the 2000A bus tie switch also trigger corresponding protection actions. For the short circuit between the power module and the fuse and the DC bus short circuit, the protection strategy that the bus tie switches at two ends of the fault side bus act and the bus at the non-fault side normally operates is realized.

[0023] The DC bus short circuit can be set as a DC main distribution board main bus short circuit point F3, a bus tie cable 4 short circuit point F4 between the two side DC main distribution boards, a test distribution board 3 short circuit point F5 and the like, the switches at two ends of the fault side bus are protected and act within 20us through the bus tie switch protection, the bus at the non-fault side normally operates, and the inverter output side short circuit point F6 comprises the output side of the converter unit (including the inverter power supply, the main push inverter unit and the side push inverter unit), and the protection is realized by the converter unit.

[0024] In some embodiments, for the short circuit between the power module and the fuse and the DC bus short circuit, the protection strategy that the bus tie switches at two ends of the fault side bus act and the bus at the non-fault side normally operates is realized.

[0025] The application aims to provide a ship DC ring network bus tie switch selective short circuit protection method, which comprehensively judges according to the current direction, the current rising rate di / dt and the overcurrent protection method, can quickly respond and selectively protect when a short circuit occurs, ensures that the response is executed before the overcurrent protection of the solid-state switch, can reliably operate when no short circuit occurs, and avoids false protection. If a short circuit fault occurs at any point of the system, the bus tie switch current direction, the current rising rate di / dt and the overcurrent protection value are comprehensively judged to realize the selective short circuit protection of the bus tie switch, and the power of the whole ship is ensured not to lose power, which is safe and reliable.

[0026] Figure 2 For the ship DC ring network system short circuit schematic, for the short circuit between the power module and the fuse and the DC bus short circuit, the protection strategy of realizing the action of the bus tie switch at both ends of the fault side bus and the normal operation of the bus tie switch of the non-fault side bus is realized. The current direction of each bus tie switch is as shown in Figure 2 When F21-F26 short circuit occurs, the current direction of each bus tie switch and the short circuit judgment method are as follows.

[0027] Step 1, the short circuit point is the left DC main distribution board 1, i.e. F21, the current direction of bus tie switch A is negative, the current direction of bus tie switch B is negative, the current direction of bus tie switch C is positive, the current direction of bus tie switch D is positive or negative, bus tie switch A and C protection, bus tie switch B and D normal operation.

[0028] Step 2, the short circuit point is between 4000A bus tie switch A and bus tie switch B, i.e. F22, the current direction of bus tie switch A is positive, the current direction of bus tie switch B is negative, the current direction of bus tie switch C is positive, the current direction of bus tie switch D is negative, bus tie switch A and B protection, bus tie switch C and D normal operation.

[0029] Step 3, the short circuit point is the right DC main distribution board 2, i.e. F23, the current direction of bus tie switch A is positive, the current direction of bus tie switch B is positive, the current direction of bus tie switch C is positive or negative, the current direction of bus tie switch D is negative, bus tie switch B and D protection, bus tie switch A and C normal operation.

[0030] Step 4, the short circuit point is between the right 2000A bus tie switch D and the test distribution board 3, i.e. F24, the current direction of bus tie switch A is positive or negative, the current direction of bus tie switch B is positive, the current direction of bus tie switch C is negative, the current direction of bus tie switch D is positive, bus tie switch C and D protection, bus tie switch A and B normal operation.

[0031] Step 5, the short circuit point is the test distribution board 3, i.e. F25, the current direction of bus tie switch A is positive or negative, the current direction of bus tie switch B is positive or negative, the current direction of bus tie switch C is negative, the current direction of bus tie switch D is positive, bus tie switch C and D protection, bus tie switch A and B normal operation.

[0032] Step 6, the short circuit point is between the left 2000A bus tie switch C and the test distribution board 3, i.e. F26, the current direction of bus tie switch A is negative, the current direction of bus tie switch B is positive or negative, the current direction of bus tie switch C is negative, the current direction of bus tie switch D is positive, bus tie switch C and D protection, bus tie switch A and B normal operation.

[0033] When short circuit protection occurs, if the current direction of the bus tie switch is opposite to the current direction of the adjacent bus tie switch, the bus tie switch executes short circuit protection, otherwise it does not execute short circuit protection, which is as follows.

[0034] Step 1, bus tie switch A short circuit protection enable condition: bus tie switch A current positive, bus tie switch B current negative or bus tie switch A current negative, bus tie switch C current positive.

[0035] Step 2, bus tie switch B short circuit protection enable condition: bus tie switch B current positive, bus tie switch D current negative or bus tie switch B current negative, bus tie switch A current positive.

[0036] Step 3, bus tie switch C short circuit protection enable condition: bus tie switch C current positive, bus tie switch A current negative or bus tie switch C current negative, bus tie switch D current positive.

[0037] Step 4, bus tie switch D short circuit protection enable condition: bus tie switch D current positive, bus tie switch C current negative or bus tie switch D current negative, bus tie switch B current positive.

[0038] Figure 3 The selective short circuit protection flowchart for the bus tie switch of the ship DC looped network system realizes selective short circuit protection of the bus tie switch. The bus tie switch controller (i.e. power electronic switch controller) is placed in the pre-charge module, the optical fiber interface is 2 in and 2 out, the bus tie switch short circuit protection function IO interface enable signal, and the main loop and the communication link are both formed in a looped network form.

[0039] S101, after the bus tie switches A-D are closed, the solid state switch module controller output current direction is collected in real time, and the information is exchanged with the adjacent bus tie switch controller through the optical fiber.

[0040] S102, the current direction of the adjacent bus tie switch controller is collected in real time through the optical fiber. When the current direction of the bus tie switch controller is the same as that of the adjacent bus tie switch controller, and the current rise rate di / dt exceeds the protection value, the bus tie switch controller short circuit protection is enabled; otherwise, it is prohibited; that is, when the bus tie switch current direction is opposite to that of the adjacent bus tie switch, the short circuit protection is executed, otherwise, the short circuit protection is not executed.

[0041] S103, the enable signal is issued to the solid state switch module controller in real time, and the module controller executes the di / dt protection and overcurrent protection functions.

[0042] S104, after the solid state switch is turned off, the fault current direction is latched, the information is uploaded to the bus tie switch controller in real time, and is transmitted to the adjacent bus tie switch controller through the optical fiber, so as to ensure that the adjacent bus tie switch controller can correctly enable the bus tie switch short circuit protection.

[0043] S105, the solid state switch di / dt protection value, the overcurrent protection value is set reasonably, when short circuit occurs, it should be able to respond quickly, ensure that the response is executed before the solid state switch overcurrent protection, when no short circuit occurs, it should be reliable operation, avoid false protection;The solid state switch di / dt protection value, the overcurrent protection value should be set reasonably, when short circuit occurs, it should be able to respond quickly, ensure that the response is executed before the solid state switch overcurrent protection, when no short circuit occurs, it should be reliable operation, avoid false protection.

[0044] Figure 4 The selective short circuit protection communication scheme diagram of the ship DC ring network system bus tie switch is shown in the figure, the bus tie switch A and the bus tie switch B are composed of the bus tie switch controller and ten solid state switch modules arranged in the 4000A bus tie switch cabinet one, the bus tie switch C and the bus tie switch D are composed of the bus tie switch controller and five solid state switch modules arranged in the 2000A bus tie switch cabinet two, each solid state switch module is connected with a module controller, and the two 4000A bus tie switch cabinets one and the two 2000A bus tie switch cabinets two form a ring network structure.

[0045] The current direction information is exchanged between the two adjacent bus tie switch controllers (in the pre-charging module) through the optical fiber, the short circuit protection enable signal is sent to the first solid state switch module controller in the bus tie switch cabinet one or the bus tie switch cabinet two through high-speed communication or DO signal, the module controller forwards the short circuit protection enable signal to the second solid state switch module controller through high-speed communication or DO signal, the second solid state switch module controller forwards to the third solid state switch module controller, and the last solid state switch module controller uploads the bus tie switch current direction information in the bus tie switch cabinet one or the bus tie switch cabinet two to the bus tie switch controller (in the pre-charging module) through high-speed communication or DO signal.

[0046] The bus tie switch controller is used for high-frequency sampling current, and is used for real-time acquisition of bus tie switch output transient current value, current direction and short circuit protection enable signal, and is used for information exchange with adjacent bus tie switches by using optical fiber communication mode, high-speed communication or I / O signal;The bus tie switch is used for fast response of on-off large current, efficient control of large power, and has the function of short circuit current limiting protection.

[0047] The above only describes the preferred specific embodiments of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for selective short-circuit protection of a busbar switch of a ship DC ring network system, characterized in that: Based on a ship DC ring network system including a DC main distribution board and a test distribution board (3), the DC main distribution board includes a port DC main distribution board (1) and a starboard DC main distribution board (2), two ends of the port DC main distribution board (1) are respectively connected to a bus tie switch A and a bus tie switch C, two ends of the starboard DC main distribution board (2) are respectively connected to a bus tie switch B and a bus tie switch D, the bus tie switch A and the bus tie switch B are connected via a cable (4), and the bus tie switch C and the bus tie switch D are connected to two ends of the test distribution board (3) via a cable (4); the bus tie switch A and the bus tie switch B are controlled by a bus tie switch controller and a plurality of solid-state switches arranged in a bus tie switch cabinet. The bus tie switch C and the bus tie switch D are composed of a bus tie switch controller and a plurality of solid-state switch modules arranged in the bus tie switch cabinet 2. Each solid-state switch module is connected to a module controller. The two bus tie switch cabinets 1 and the two bus tie switch cabinets 2 form a ring network structure. The two adjacent bus tie switch controllers exchange current direction information through optical fibers and send a short-circuit protection enable signal to the first module controller in the bus tie switch cabinet 1 or the bus tie switch cabinet 2. The module controller forwards the signal to the next module controller, and so on. The last module controller uploads the bus tie switch current direction information to the bus tie switch controller. The method comprises the following steps: S101: After the bus tie switches A to D are closed, the acquisition module controller outputs the current direction and exchanges information with the adjacent bus tie switch controllers via optical fiber information. S102, collecting the current direction of the adjacent bus tie switch controller in real time through optical fiber, and when it is detected that the current direction is the same as that of the adjacent bus tie switch controller and the current rising rate of change di / dt exceeds the protection value, the short circuit protection of the bus tie switch controller is enabled; Otherwise prohibited; S103, sending an enable signal to the module controller in real time, and the module controller performs di / dt protection and overcurrent protection functions; S104: After the solid-state switch is disconnected, the current direction before the fault is latched and uploaded to the bus tie switch controller in real time. The information is also transmitted to the adjacent bus tie switch controller via optical fiber to ensure that the adjacent bus tie switch controller can correctly enable the bus tie switch short-circuit protection.

2. A method for selective short-circuit protection of a bus tie switch of a ship DC ring network system according to claim 1, characterized in that: If the current direction of bus tie switch A is negative, the current direction of bus tie switch B is negative, the current direction of bus tie switch C is positive, and the current direction of bus tie switch D is positive or negative, bus tie switch A and bus tie switch C are protected, and bus tie switch B and bus tie switch D are operating normally, then the short-circuit point is determined to be the port side DC main switchboard (1); If the current direction of bus tie breaker A is positive, the current direction of bus tie breaker B is negative, the current direction of bus tie breaker C is positive, and the current direction of bus tie breaker D is negative, bus tie breaker A and bus tie breaker B are protected, and bus tie breaker C and bus tie breaker D are operating normally, then the short-circuit point is determined to be between bus tie breaker A and bus tie breaker B; If the current direction of bus tie switch A is positive, the current direction of bus tie switch B is positive, the current direction of bus tie switch C is positive or negative, the current direction of bus tie switch D is negative, bus tie switches B and D are protected, and bus tie switches A and C are operating normally, then the short-circuit point is determined to be the starboard DC main switchboard (2); If the current direction of bus tie switch A is negative, the current direction of bus tie switch B is positive or negative, the current direction of bus tie switch C is negative, the current direction of bus tie switch D is positive, bus tie switch C and bus tie switch D are protected, and bus tie switch A and bus tie switch B are operating normally, then the short circuit point is determined to be between the port bus tie switch C and the test distribution board (3); If the current direction of bus tie switch A is positive or negative, the current direction of bus tie switch B is positive or negative, the current direction of bus tie switch C is negative, the current direction of bus tie switch D is positive, bus tie switch C and bus tie switch D are protected, and bus tie switch A and bus tie switch B are operating normally, then the short-circuit point is determined to be the test distribution board (3); If the current direction of bus tie switch A is positive or negative, the current direction of bus tie switch B is positive, the current direction of bus tie switch C is negative, the current direction of bus tie switch D is positive, bus tie switch C and bus tie switch D are protected, and bus tie switch A and bus tie switch B are operating normally, then the short circuit point is determined to be between the starboard bus tie switch D and the test distribution board (3).

3. A method for selective short-circuit protection of a bus tie switch of a ship DC ring network system according to claim 1 or 2, characterized in that: When the current of bus tie breaker A is positive and the current of bus tie breaker B is negative, or when the current of bus tie breaker A is negative and the current of bus tie breaker C is positive, the short-circuit protection of bus tie breaker A is enabled; When the current of bus tie breaker B is positive and the current of bus tie breaker D is negative, or when the current of bus tie breaker B is negative and the current of bus tie breaker A is positive, the short-circuit protection of bus tie breaker B is enabled; When the current of bus tie breaker C is positive and the current of bus tie breaker A is negative, or when the current of bus tie breaker C is negative and the current of bus tie breaker D is positive, the short-circuit protection of bus tie breaker C is enabled; When the current of bus tie switch D is positive and the current of bus tie switch C is negative, or when the current of bus tie switch D is negative and the current of bus tie switch B is positive, the short-circuit protection of bus tie switch D is enabled.

4. A method for selective short-circuit protection of a bus tie switch of a ship DC ring network system according to claim 3, characterized in that: The bus tie switch controller is placed in the pre-charging module.

Images