Power system protection method for MVDC electric propulsion ship, and device thereof

Abstract

Disclosed in one embodiment of the present invention is a power system protection method for an MVDC electric propulsion ship, comprising the steps of: monitoring whether an accident has occurred in the power system of the MVDC electric propulsion ship; determining, as a result of performing the monitoring, the type of accident that has occurred when it is detected that the accident has occurred in the power system; determining a protection procedure corresponding to the determined type of accident; and protecting the power system on the basis of the determined protection procedure.

Description

Power system protection method and device for MVDC electric propulsion vessels

[0001] The present invention relates to a method for effectively protecting the entire power system in the event that an accident occurs at a specific location in the power system.

[0002] MVDC (Medium-Voltage Direct Current) refers to a power supply method that transmits and distributes medium-voltage electricity between 1.5 and 35 kV as direct current.

[0003] For the purpose of decarbonization, energy efficiency is just as important as increasing capacity for the utilization of eco-friendly and renewable energy with DC power characteristics, and MVDC transmission and distribution systems are a necessary technology to enhance the efficiency of such energy.

[0004] Meanwhile, a fuel cell is an energy conversion device that directly converts the chemical energy of fuel into electrical energy through an electrochemical reaction. Unlike batteries, it can continuously produce electrical energy without recharging as long as fuel is supplied. In particular, hydrogen fuel cells have the advantage of being pollution- and noise-free, making them essential for realizing MVDC electric ships.

[0005] Fuel cells are LVDC outputs due to their characteristics, and when implementing an MVDC electric propulsion vessel, the distribution section inside the vessel is generally configured as an MVDC system. Among the technologies for connecting the MVDC (system) and the LVDC (fuel cell), the most basic conventional technology is a method as shown in Fig. 1, which uses several insulating modules to connect the LVDC lines in parallel and the MVDC lines in series.

[0006] Figure 1 is a diagram illustrating a conventional method in which a fuel cell and an MVDC system are connected.

[0007] Referring to FIG. 1, Fuel Cell 1 (10) is V corresponding to LVDCL (11) outputs, and the output V L Through a converter composed of a total of (n+1) modules, the MVDC output V M It can be seen that it is converted to (12). At this time, the MVDC output V M (12) is the output of each module, V m,0 (12a) to V m,n It becomes the sum of (12n).

[0008] The technical problem that the present invention aims to solve is to provide a method for protecting the power system of an MVDC electric propulsion vessel and a device for implementing the method.

[0009] A method according to an embodiment of the present invention for solving the above technical problem comprises: a step of monitoring whether an accident has occurred in the power system of an MVDC electric propulsion vessel; a step of determining the type of accident that has occurred if, as a result of performing the monitoring, it is detected that an accident has occurred in the power system; a step of determining a protection procedure corresponding to the determined type of accident; and a step of performing protection on the power system based on the determined protection procedure.

[0010] An apparatus according to another embodiment of the present invention for solving the above technical problem comprises: a memory in which at least one program is stored; and a processor that performs calculations by executing the at least one program, wherein the processor monitors whether a fault has occurred in the power system of an MVDC electric propulsion vessel, and if, as a result of performing the monitoring, it detects that a fault has occurred in the power system, it determines the type of the fault that has occurred, determines a protection procedure corresponding to the determined type of fault, and controls the power system to perform protection based on the determined protection procedure.

[0011] One embodiment of the present invention may provide a computer-readable recording medium storing a program for executing the method.

[0012] According to the present invention, the power system of an MVDC electric propulsion vessel can be effectively protected.

[0013] Figure 1 is a diagram illustrating a conventional method in which a fuel cell and an MVDC system are connected.

[0014] FIG. 2 is a schematic diagram for explaining, module by module, the components included in an MVDC electric propulsion vessel to which the method according to the present invention is applied.

[0015] FIG. 3 is a schematic diagram showing a power system of an MVDC electric propulsion vessel according to another embodiment of the present invention.

[0016] Figure 4 is a diagram schematically showing the number of cases in which an accident occurs in the power system of an MVDC electric propulsion vessel.

[0017] FIG. 5 is a diagram illustrating an exemplary circuit breaker used in the method according to the present invention.

[0018] Figures 6 and 7 are exemplary drawings showing a table referenced by a power system protection device.

[0019] FIG. 9 is a diagram illustrating a submodule included in the processor of FIG. 8.

[0020] FIG. 10 is a flowchart illustrating an example of a power system protection method for an MVDC electric propulsion vessel according to the present invention.

[0021] A method according to an embodiment of the present invention for solving the above technical problem comprises: a step of monitoring whether an accident has occurred in the power system of an MVDC electric propulsion vessel; a step of determining the type of accident that has occurred if, as a result of performing the monitoring, it is detected that an accident has occurred in the power system; a step of determining a protection procedure corresponding to the determined type of accident; and a step of performing protection on the power system based on the determined protection procedure.

[0022] In the above method, the protection procedure may be a procedure performed using a multi-use semiconductor switch.

[0023] In the above method, the type of accident that occurred may include the location where the accident occurred.

[0024] In the above method, the generation location may be one of a DC bus, an AC generator, a fuel cell, a fuel cell corresponding rectifier, an MMC drive, a permanent magnet motor, a transistor, a transformer, a low-voltage distribution unit (LV SWBD), and a fuel cell converter.

[0025] In the above method, the step of determining the protection procedure can be determined based on a table that matches the location of the accident with the operation of the circuit breaker.

[0026] In the above method, the table may be a table including detailed settings for a generator, fuel cell, propulsion motor, transformer, and LVAC.

[0027] In the above method, the step of determining the protection procedure may distinguish between a first case in which a fault occurs in a submodule and a second case in which a fault occurs in the entire converter when a fault occurs in an MMC drive constituting the power system, and determine different protection procedures.

[0028] In the above method, the step of determining the protection procedure may distinguish between a third case in which a fault occurs in a unit rectifier and a fourth case in which a fault occurs in a whole rectifier when a fault occurs in a fuel cell converter constituting the power system, and determine different protection procedures.

[0029] In the above method, the MVDC electric propulsion vessel may be based on high voltage direct current (MVDC) for the main distribution unit (MSBD) and low voltage alternating current (LVAC) for the secondary distribution unit (SSBD).

[0030] In the above method, the power supplied to the power system may be power generated by adjusting the driving ratio of the generator, fuel cell, and ESS.

[0031] An apparatus according to another embodiment of the present invention for solving the above technical problem comprises: a memory in which at least one program is stored; and a processor that performs calculations by executing the at least one program, wherein the processor monitors whether a fault has occurred in the power system of an MVDC electric propulsion vessel, and if, as a result of performing the monitoring, it detects that a fault has occurred in the power system, it determines the type of the fault that has occurred, determines a protection procedure corresponding to the determined type of fault, and controls the power system to perform protection based on the determined protection procedure.

[0032] In the above device, the protection procedure may be a procedure performed using a multiple semiconductor switch.

[0033] In the above device, the multi-use semiconductor switch can be implemented as a converter or inverter connected to the distribution section of the power system.

[0034] In the above device, the processor can make a determination based on a table that matches the location of the accident with the operation of the circuit breaker.

[0035] One embodiment of the present invention may provide a computer-readable recording medium storing a program for executing the method.

[0036] The present invention is capable of various modifications and may have various embodiments; specific embodiments are illustrated in the drawings and described in detail in the detailed description. The effects and features of the present invention, and the methods for achieving them, will become clear by referring to the embodiments described below in detail together with the drawings. However, the present invention is not limited to the embodiments disclosed below but can be implemented in various forms.

[0037] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. When describing with reference to the drawings, identical or corresponding components are given the same reference numerals, and redundant descriptions thereof will be omitted.

[0038] In the following embodiments, terms such as first, second, etc. are used not in a limiting sense, but for the purpose of distinguishing one component from another component.

[0039] In the following embodiments, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0040] In the following embodiments, terms such as "include" or "have" mean that the features or components described in the specification are present, and do not preclude the possibility that one or more other features or components may be added.

[0041] Where an embodiment can be implemented differently, a specific process sequence may be performed differently from the order described. For example, two processes described consecutively may be performed substantially simultaneously or proceed in the reverse order of the description.

[0042] FIG. 2 is a schematic diagram for explaining, module by module, the components included in an MVDC electric propulsion vessel to which the method according to the present invention is applied.

[0043] FIG. 2 illustrates an exemplary power system (20) of an MVDC electric propulsion vessel that operates based on power produced from multiple power sources. Referring to FIG. 2, it can be seen that the power system (20) of the MVDC electric propulsion vessel includes a first fuel cell (21), a first generator (22), a first fuel cell corresponding converter (23), a first generator corresponding rectifier (24), a first MVDC distribution unit (25), a first DC propulsion drive (26), a first propulsion motor (27), a first propeller (28), and a first AC load unit (29).

[0044] The first fuel cell (21) of FIG. 2 is a device capable of directly producing and supplying electricity to the outside through a chemical reaction between fuel and an oxidant. It is similar to a battery in that it is a module that supplies electricity, but it differs from a conventional battery in that it can continuously generate electricity when fuel is continuously supplied. In particular, fuel cells are an essential energy source for realizing low-carbon and carbon-free electric propulsion vessels, as they can use LNG, ammonia, and hydrogen fuels in compliance with carbon regulations. In one embodiment of the present invention, the first fuel cell (21) may be a solid oxide fuel cell (SOFC) or a polymer electrolyte membrane fuel cell (PEMFC). When implementing an MVDC electric propulsion vessel, the internal power distribution section of the vessel is generally configured as an MVDC system, whereas the first fuel cell (21) has low-voltage direct current (LVDC) output characteristics, so a first fuel cell corresponding converter (23) that includes a transformer is essential to connect the MVDC (system) and the LVDC (fuel cell).

[0045] The first generator (22) of FIG. 2 is a device that generates power separately from the first fuel cell (21). In the present invention, the first generator (22) may be a 6-phase engine generator. Power output from the first generator (22) may be transmitted to the first MVDC distribution unit (25) via a first generator corresponding rectifier (24) connected through a switch. In one embodiment of the present invention, the first generator (22) may be a diesel generator.

[0046] The first fuel cell corresponding converter (23) of FIG. 2 can boost the output of the first fuel cell (21), which is an LVDC output, and rectify it with diode-based rectification characteristics to transmit the output of the first fuel cell (21) to the first MVDC distribution unit (25).

[0047] The first MVDC distribution unit (25) of FIG. 2 is a distribution unit that supplies MVDC-class power to the entire MVDC electric propulsion vessel and is essential for implementing an MVDC power system. The first MVDC distribution unit (25) can be connected to the power system of an MVDC electric propulsion vessel arranged symmetrically and identically to FIG. 2 through a bus-tie breaker, and this will be described later in FIG. 3.

[0048] The first DC propulsion drive (26) of FIG. 2 is a device that operates by receiving MVDC power through a connection to the first MVDC distribution unit (25), and is connected to the first propulsion motor (27) to control and manage power so that the first propulsion motor (27) can propel the ship. The first DC propulsion drive (26) can play a key role in controlling the speed of the MVDC electric propulsion ship by adjusting the amount and quality of power delivered to the first propulsion motor (27).

[0049] The first propulsion motor (27) of FIG. 2 is a device that converts electrical energy supplied from the first DC propulsion drive (26) into mechanical rotational energy. The propulsion motor (27) may be a permanent magnet motor that physically contains a permanent magnet to rotate when power is supplied, and depending on the embodiment, it may be implemented as an induction motor or a superconducting motor. The first propeller (28) of FIG. 2 is directly connected to the first propulsion motor (27) and rotates at a speed proportional to the rotation of the first propulsion motor (27) to generate thrust for the MVDC electric propulsion vessel.

[0050] The first AC load section (29) of FIG. 2 is a part that includes an AC load for receiving AC power, and includes a plurality of modules or devices including a step-down transformer, etc. The first AC load section (29) will be explained in FIG. 3.

[0051] The power system (20) of the MVDC electric propulsion vessel illustrated in FIG. 2 includes the following improved features. First, the AC output from the first generator (22) is transmitted to the first generator corresponding rectifier (24) through a switch, converted into an MVDC output, and then transmitted to the first MVDC distribution unit (25). However, as illustrated in FIG. 2, the power from the first generator (22) can be transmitted directly to the first AC load terminal (29) through additional wires without passing through the first MVDC distribution unit (25) before reaching the first generator corresponding rectifier (24). Although not shown in FIG. 2, the power control device (700) controls the operation of the switch installed between the first generator (22) and the first generator corresponding rectifier (24) so ​​that at least a portion of the AC output generated from the first generator (22) is transmitted directly to the first AC load terminal (29) without passing through the first MVDC distribution unit (25), and the control characteristics of the power control device (700) will be described later in FIG. 7 to FIG. 9.

[0052] The power from the first generator (22) delivered to the first AC load section (29) not only enables the AC load included in the first AC load section (29) to operate stably, but also allows the first generator (22) to continuously supply power to the AC load even if there is a problem with the first MVDC distribution section (25), which is the main switchboard, as long as the first generator (22) does not stop.

[0053] In addition, in order for the first AC load section (29) to receive AC power from the first MVDC distribution section (25), which is the main distribution board, the AC power of the first generator (22) must be converted into DC power corresponding to the first MVDC distribution section (25) and then converted back into AC power. Therefore, energy loss occurs during the two conversion processes, and the volume and weight of the module for each conversion may act as a burden on the entire MVDC electric propulsion vessel. However, according to the present invention, since the AC power of the first generator (22) is delivered to the first AC load section (29) without passing through the first MVDC distribution section (25), energy loss can be minimized. In particular, considering that most of the equipment operated when the vessel is docked at a port and performing tasks such as unloading receives AC power supply, the configuration according to the present invention can minimize loss compared to delivery to the AC load section through the MVDC distribution section.

[0054] FIG. 3 is a schematic diagram showing a power system of an MVDC electric propulsion vessel according to another embodiment of the present invention.

[0055] The power system of the MVDC electric propulsion vessel shown in FIG. 3 is an embodiment that further extends the power system (20) of the MVDC electric propulsion vessel described in FIG. 2, and has the characteristic of being able to selectively connect two first MVDC distribution units (25) of the power system (20) of the MVDC electric propulsion vessel through the bus-tie breaker of FIG. 2. That is, the power system (30) of the MVDC electric propulsion vessel shown in FIG. 3 is characterized by being implemented symmetrically with respect to the bus-tie breaker.

[0056] The sub-components included in the power system on the right side of FIG. 3 may each be referred to as the second fuel cell (31), the second generator (32), the second fuel cell corresponding rectifier (33), the second generator corresponding rectifier (34), the second MVDC distribution unit (35), the second DC propulsion drive (36), the second propulsion motor (37), the second propeller (38), and the second AC load unit (39). Additionally, below, the power system on the left side of FIG. 3 will be abbreviated as the first power system, and the power system on the right side of FIG. 3 will be abbreviated as the second power system.

[0057] Figure 4 is a diagram schematically showing the number of cases in which an accident occurs in the power system of an MVDC electric propulsion vessel.

[0058] As shown in Fig. 4, the faults in the power system of the MVDC electric propulsion vessel described in Fig. 3 can be broadly classified into nine types.

[0059] First, ① in FIG. 4 refers to the case where an accident occurs in the main distribution unit of the power system. More specifically, an accident in the main distribution unit (MSBD: Main Switchboard) of the power system refers to an accident in at least one of the first MVDC distribution unit (25) and the second MVDC distribution unit (35) of FIG. 3.

[0060] ② in FIG. 4 refers to a case where an accident occurs on the AC side of the power system. More specifically, an accident on the AC side of the power system refers to an accident that occurs near the first generator (22) and the second generator (32) in FIG. 3, and is a broad concept that includes cases where two wires are short-circuited (2 line-to-line short), three phases are short-circuited (3 phase short), and fault impedance occurs.

[0061] ③ of FIG. 4 refers to a case where an accident occurs to the fuel cell and the fuel cell-compatible converter. More specifically, an accident to the fuel cell and the fuel cell-compatible converter refers to an accident that occurs in at least one of the first fuel cell (21), the first fuel cell-compatible converter (23), the second fuel cell (31), and the second fuel cell-compatible rectifier (33) of FIG. 3.

[0062] ④ of FIG. 4 refers to the case where an accident occurs to the rectifier corresponding to the generator. More specifically, an accident to the rectifier corresponding to the generator refers to an accident that occurs in at least one of the first generator-corresponding rectifier (24) and the second generator-corresponding rectifier (34) of FIG. 3.

[0063] ⑤ in FIG. 4 represents the case where an accident occurs to the MMC (Modular Multilevel Converter) drive. In an MVDC electric propulsion vessel, the MMC drive is a propulsion drive specialized for high-capacity and high-voltage systems and can be a type of the first DC propulsion drive (26) described in FIG. 3. The MMC drive is a device that operates by receiving MVDC power supplied through a connection to the first MVDC distribution unit (25), and is connected to the first propulsion motor (27) to control and manage power so that the first propulsion motor (27) can propel the vessel. More specifically, an accident to the MMC drive can be classified into a first case where an accident occurs in a submodule and a second case where an accident occurs in the whole converter, and in the present invention, different protection measures are applied according to the first and second cases. The protection measures will be described later in FIG. 6.

[0064] ⑥ of FIG. 4 refers to a case where an accident occurs to a propulsion motor (permanent magnet motor). More specifically, an accident to a propulsion motor refers to an accident that occurs in at least one of the first propulsion motor (27) and the second propulsion motor (37) of FIG. 3.

[0065] ⑦ in FIG. 4 represents a case where an accident occurs to the transformer. More specifically, the accident to the transformer refers to an accident that occurs in the step-down transformer included in the first AC load section (29) and the second AC load section (39) of FIG. 3, respectively.

[0066] Figure 4, ⑧ represents the case where a fault occurs in the Low Voltage Alternating Current (LVAC) terminal. More specifically, the fault in the Low Voltage Alternating Current terminal refers to a fault that occurs in the Sub Switchboard (SSBD) connected to the first AC load terminal (29) and the second AC load terminal (39) of Figure 3.

[0067] ⑨ in FIG. 4 represents a case where an accident occurs to a fuel cell converter. More specifically, an accident to a fuel cell converter refers to an accident that occurs in a converter located between the first fuel cell corresponding converter (23) and the second fuel cell corresponding rectifier (33) of FIG. 3, which are connected to the first MVDC distribution unit (25) and the second MVDC distribution unit (35), respectively. In particular, an accident to a fuel cell converter can be classified into a third case in which an accident occurs to a unit rectifier constituting the fuel cell converter and a fourth case in which an accident occurs to a whole rectifier, and in the present invention, different protection measures are applied according to the third case and the fourth case. The different protection measures for the third case and the fourth case will be described later in FIG. 7.

[0068] Although not illustrated in FIG. 4, the power system protection device according to the present invention preliminarily monitors the nine types of faults described in FIG. 4, and when at least one of the nine types of faults occurs, it can perform pre-set protection measures according to the characteristics of each fault. The power system protection device will be described later through FIG. 7 to 9.

[0069] FIG. 5 is a diagram illustrating an exemplary circuit breaker used in the method according to the present invention.

[0070] The power system protection device according to the present invention can perform protection measures by rapidly disconnecting the power system where a fault has occurred through the switch system shown in FIG. 5. The switch system shown in FIG. 5 is a switch effective in a medium-voltage direct current (MVDC) based power system, and unlike a single-use fuse, it is multi-use and is implemented as a semiconductor so as to operate at a speed of tens of microseconds. The power system protection device can quickly take measures to prevent fault current from flowing to the components included in the power system when a fault occurs by generating a control signal for a converter / inverter (530) connected to the distribution unit (510) and rapidly excluding the components included in the MVDC power system. In addition, the power system protection device can fundamentally prevent a case where an accident in the first power system has an adverse effect on the second power system, or an accident in the second power system has an adverse effect on the first power system, by generating and transmitting a control signal to quickly open the bus-tie circuit breaker (550) connecting the first MVDC distribution unit (25) and the second MVDC distribution unit (35) of FIG. 3.

[0071] Ultimately, the power system protection device monitors for the occurrence of an accident in the power system, and when it detects that an accident has occurred, it can safely protect the power system of the MVDC electric propulsion vessel by generating a control signal to operate the converter / inverter (530) closest to the location where the accident occurred as an open switch or a closed switch.

[0072] Figures 6 and 7 are exemplary drawings showing a table referenced by a power system protection device.

[0073] The power system protection device can determine the protection procedure based on the table shown in FIGS. 6 and 7. The table shown in FIGS. 6 and 7 is data that matches the location of the fault with the action sequence of the circuit breaker when a fault occurs in the power system, and can be modified by an authorized administrator. More specifically, the table shown in FIGS. 6 and 7 is characterized by matching the nine types of faults described in FIG. 4 with the operation methods of the circuit breaker in the generator, fuel cell, propulsion motor (PM), transformer (TR), and LVAC.

[0074] In one embodiment, when the power system protection device detects that a fault has occurred in the main distribution section (DC Bus) of the power system as shown in ① of FIG. 4, it can generate a control signal to open the AC circuit breaker of the generator, stop the converter of the fuel cell, stop the converter of the MMC drive and PM motor, and open the star point circuit breaker, while not taking any action with respect to the transformer (TR) and LVAC, and transmit it to each module.

[0075] In one embodiment, when the power system protection device detects that a fault has occurred on the AC side of the power system as shown in ② of FIG. 4, it can open the AC circuit breaker of the generator, de-excite the generator, open the AC circuit breaker located between the AC generator and the transformer for the transformer, and then generate and transmit a control signal to each module so that no action is taken for the fuel cell, MMC drive, PM motor, and LVAC. At this time, the fault on the AC side of the power system is a broad concept that includes cases such as a two-line-to-line short, a three-phase short, or the occurrence of fault impedance.

[0076] In one embodiment, when the power system protection device detects that a fault has occurred in the fuel cell and the fuel cell corresponding converter as in ③ of FIG. 4, it can generate a control signal to stop only the converter of the fuel cell and transmit it to each module.

[0077] In one embodiment, when the power system protection device detects that a fault has occurred in the rectifier corresponding to the generator as shown in ④ of FIG. 4, it can generate a control signal to open the AC circuit breaker of the generator, stop the converter of the fuel cell, stop the converter of the MMC drive and PM motor, and open the star point circuit breaker, while not taking any action (No action) with respect to the transformer (TR) and LVAC, and transmit it to each module.

[0078] In one embodiment, when the power system protection device detects that a fault has occurred in the MMC (Modular Multilevel Converter) drive as shown in ⑤ of FIG. 4, it may initiate protection measures by classifying the case into a first case in which a fault has occurred in a submodule and a second case in which a fault has occurred in the whole converter. In the first case, the power system protection device may generate and transmit a control signal to each module to bypass the submodule in which the fault occurred in the MMC drive and not take any other action. Meanwhile, in the second case, the power system protection device may generate and transmit a control signal to each module to open the AC circuit breaker of the generator, de-excite the generator, stop the fuel cell converter, stop the MMC drive and PM motor converters, open the starpoint circuit breaker, and not take any action regarding the transformer (TR) and LVAC.

[0079] In one embodiment, when the power system protection device detects that a fault has occurred in the propulsion motor (permanent magnet motor) as shown in ⑥ of FIG. 4, it can generate a control signal to stop the converters of the MMC drive and PM motor and open the starpoint circuit breaker and transmit it to each module.

[0080] In one embodiment, when the power system protection device detects that a fault has occurred in the transformer as shown in ⑦ of FIG. 4, it can generate a control signal to open only the transformer breakers and not take any action, and transmit it to each module.

[0081] In one embodiment, when the power system protection device detects that a fault has occurred in the Low Voltage Alternating Current (LVAC) terminal as shown in ⑧ of FIG. 4, it can generate a control signal to open the transformer circuit breakers and open the bus-tie circuit breaker, and then transmit the signal to each module so as not to take any action.

[0082] In one embodiment, when the power system protection device detects that a fault has occurred in the fuel cell converter as shown in ⑨ of FIG. 4, it can perform protection measures by classifying the case into a third case in which a fault has occurred in a unit rectifier constituting the fuel cell converter and a fourth case in which a fault has occurred in the whole rectifier. In the third case, the power system protection device can generate a control signal to bypass only the faulty unit rectifier and transmit it to each module. Meanwhile, in the fourth case, the power system protection device can generate a control signal to open the AC circuit breaker of the generator, de-energize the generator, stop the fuel cell converter, stop the converters of the MMC drive and PM motor, and open the starpoint circuit breaker, while not taking any action regarding the transformer and LVAC, and transmit it to each module.

[0083] FIG. 8 is a block diagram showing an example of a power system protection device according to the present invention.

[0084] Referring to FIG. 8, it can be seen that the power system protection device (800) includes a communication unit (810), a processor (830), and a memory (850).

[0085] The communication unit (810) may include one or more components that enable wired / wireless communication with an external device. For example, the communication unit (810) may include at least one piece of hardware necessary to implement short-range communication such as Wi-Fi or Bluetooth in a network provided by a communication network, or to implement various communications including the Internet when a LAN cable is connected. Additionally, the communication unit (810) may include a module for supporting power line communication (PLC).

[0086] Memory (850) is hardware that stores various data processed within the power system protection device (800) and can store programs for processing and controlling the processor (830). Memory (850) may include RAM (random access memory) such as DRAM (dynamic random access memory) and SRAM (static random access memory), ROM (read-only memory), EEPROM (electrically erasable programmable read-only memory), CD-ROM, Blu-ray or other optical disc storage, HDD (hard disk drive), SSD (solid state drive), or flash memory.

[0087] The processor (830) can control the overall operation of the power system protection device (800). For example, the processor (830) can control the operation of the input unit (not shown), display (not shown), communication unit (810), memory (850), etc. included in the power system protection device (800) by executing programs stored in memory (850).

[0088] As an example, the processor (830) can monitor whether a fault has occurred in the power system of an MVDC electric propulsion vessel, and if, as a result of the monitoring, it detects that a fault has occurred in the power system, determine the type of fault that has occurred, determine a protection procedure corresponding to the determined type of fault, and control the power system to perform protection based on the determined protection procedure.

[0089] In one embodiment, the protection procedure performed by the processor (830) may be a procedure performed using a multi-use semiconductor switch. A mechanical DC disconnector may be installed between the converter and the inverter connected to the power distribution unit, which completely cuts off the flow of current in the event of an accident or emergency to prevent secondary damage such as equipment damage and fire.

[0090] In one embodiment, as information analyzed by the processor (830), the type of fault that occurred in the power system may include the location of the fault and may be at least one of a DC bus, an AC generator, a fuel cell, a fuel cell corresponding rectifier, an MMC drive, a permanent magnet motor, a transistor, a transformer, a low-voltage distribution unit (LV SWBD), and a fuel cell converter.

[0091] In one embodiment, the processor (830) may determine the protection procedure based on a table that matches the location of the accident with the operation of the circuit breaker, and the table may be a table that includes detailed settings for a generator, fuel cell, propulsion motor, transformer, and LVAC. This has been described in FIGS. 6 and 7.

[0092] In one embodiment, the processor (830), while determining the protection procedure, can distinguish between a first case in which a fault occurs in a submodule and a second case in which a fault occurs in the entire converter when a fault occurs in an MMC drive constituting the power system, and determine different protection procedures.

[0093] In one embodiment, the processor (830), while determining the protection procedure, can distinguish between a third case in which a fault occurs in a unit rectifier and a fourth case in which a fault occurs in a whole rectifier when a fault occurs in a fuel cell converter constituting the power system, and determine different protection procedures.

[0094] In one embodiment, the power system of an MVDC electric propulsion vessel to which a power system protection device (800) is applied may be based on high voltage direct current (MVDC) for the main distribution unit (MSBD) and low voltage alternating current (LVAC) for the secondary distribution unit (SSBD), and the power supplied to the power system may be power generated by adjusting the driving ratio of a generator, a fuel cell, and an ESS. In one embodiment, the secondary distribution unit (SSBD) may be based on low voltage direct current (LVDC).

[0095] When the power system protection device (800) is implemented as a physical device, the processor (830) may be implemented using at least one of ASICs (application specific integrated circuits), DSPs (digital signal processors), DSPDs (digital signal processing devices), PLDs (programmable logic devices), FPGAs (field programmable gate arrays), controllers, micro-controllers, microprocessors, and other electrical units for performing functions.

[0096] In addition, when the power system protection device (800) in the present invention is implemented in the form of an application (program) that runs on an integrated data processing device such as a server, the processor (830) and memory (850) included in the power system protection device (800) may be implemented in the form of a virtual machine that implements hardware such as DSPs, microcontrollers, RAM, ROM, HDD, etc., as software (command script).

[0097] In FIGS. 2 and 3, the location of the power system protection device (800) is not specified. The location of the power system protection device (800) is variable, and it can be installed and operated without restriction as long as it is a location where it can perform the function according to the present invention. In addition, as described above, the power system protection device (800) is implemented as an application, which is a logical device, and is mounted on the MCU of an MVDC electric propulsion vessel to participate in the operation of various circuit breakers included in the power system.

[0098] In addition, the power system protection device (800) can perform operations to efficiently control the power system of the MVDC electric propulsion vessel during normal times when no accident occurs in the power system. That is, the power system protection device (800) can comprehensively control the power system so that it operates smoothly even if no accident occurs in the power system of the MVDC electric propulsion vessel, and the operation of the power system protection device (800) at this time has already been explained in the description of FIG. 3.

[0099] In one embodiment, the power system protection device (800) can determine a power source that supplies power to the load end of the power system of an MVDC electric propulsion vessel, control the generation of power based on the determined power source, and control the power generated from the determined power source to be supplied to the load end without passing through the MVDC distribution unit. In addition, the power system controlled by the power system protection device (800) may be implemented symmetrically with respect to a bus-tie breaker, with respect to the power source, the MVDC distribution unit, and the load end. In addition, as one embodiment, the power source in the power system controlled by the power system protection device (800) may be at least one of a diesel generator, a solid oxide fuel cell, and an energy storage system (ESS).

[0100] FIG. 9 is a diagram illustrating a submodule included in the processor of FIG. 8.

[0101] Referring to FIG. 9, it can be seen that the processor (830) includes a system monitoring unit (831), an accident type determination unit (833), a protection procedure determination unit (835), and a protection procedure processing unit (837). Since the system monitoring unit (831), the accident type determination unit (833), the protection procedure determination unit (835), and the protection procedure processing unit (837) illustrated in FIG. 9 are logically and conceptually separated modules to explain the process performed by the processor (830) in the process of implementing the method according to the present invention, FIG. 9 shows four sub-modules, but depending on the embodiment, the processor (830) may include fewer than four or more than four sub-modules.

[0102] In addition, since the system monitoring unit (831), fault type determination unit (833), protection procedure determination unit (835) and protection procedure processing unit (837) of FIG. 9 are sub-modules of the processor (830), they can be implemented using at least one of ASICs (application specific integrated circuits), DSPs (digital signal processors), DSPDs (digital signal processing devices), PLDs (programmable logic devices), FPGAs (field programmable gate arrays), controllers, micro-controllers, microprocessors, and other electrical units for performing functions, just like the processor (830).

[0103] The system monitoring unit (831) monitors whether an accident has occurred in the power system of the MVDC electric propulsion vessel and can transmit the results of the monitoring to the accident type determination unit (833).

[0104] The accident type determination unit (833) can determine the type of accident that occurred when it detects that an accident has occurred in the power system.

[0105] The protection procedure determination unit (835) can determine a protection procedure corresponding to the type of accident determined by the accident type determination unit (833).

[0106] The protection procedure processing unit (837) can generate a control signal to perform protection on the power system based on the determined protection procedure and process it to be transmitted to each module.

[0107] FIG. 10 is a flowchart illustrating an example of a power system protection method for an MVDC electric propulsion vessel according to the present invention.

[0108] Since the method according to FIG. 10 can be implemented by the power system protection device (800) and the sub-modules included in the device described in FIG. 8, the following description will be made with reference to FIG. 2 to FIG. 9, and descriptions that overlap with previously explained content will be omitted.

[0109] The power system protection device (800) can monitor whether an accident has occurred in the power system of an MVDC electric propulsion vessel (S1010).

[0110] When the power system protection device (800) detects that an accident has occurred in the power system, it can determine the type of accident that has occurred (S1030).

[0111] The power system protection device (800) can determine a protection procedure corresponding to the type of fault determined in step S1030 (S1050).

[0112] The power system protection device (800) can generate a control signal to perform protection on the power system based on a determined protection procedure and process it to be transmitted to each module (S1070).

[0113] According to the present invention, the power system of an MVDC electric propulsion vessel can be effectively protected.

[0114] The embodiments according to the present invention described above may be implemented in the form of a computer program that can be executed through various components on a computer, and such a computer program may be recorded on a computer-readable medium. In this case, the medium may include a magnetic medium such as a hard disk, a floppy disk, and a magnetic tape, an optical recording medium such as a CD-ROM and a DVD, a magneto-optical medium such as a floptical disk, and a hardware device specifically configured to store and execute program instructions, such as a ROM, RAM, or flash memory.

[0115] Meanwhile, the above-mentioned computer program may be one specifically designed and configured for the present invention, or one known and available to those skilled in the art of computer software. Examples of computer programs may include machine code, such as that generated by a compiler, as well as high-level language code that can be executed by a computer using an interpreter, etc.

[0116] The specific embodiments described in this invention are examples and do not limit the scope of the invention in any way. For the sake of brevity of the specification, descriptions of prior electronic configurations, control systems, software, and other functional aspects of said systems may be omitted. Additionally, the connections of lines or connecting members between components shown in the drawings are illustrative of functional connections and / or physical or circuit connections, and may be replaced or additionally represented as various functional connections, physical connections, or circuit connections in actual devices. Furthermore, unless specifically stated as “essential,” “importantly,” etc., a component may not be strictly necessary for the application of the invention.

[0117] In the specification of the present invention (particularly in the claims), the use of the term “above” and similar descriptive terms may be in both singular and plural. Furthermore, where a range is described in the present invention, it is to include the invention to which individual values ​​belonging to said range are applied (unless otherwise stated), and is equivalent to describing each individual value constituting said range in the detailed description of the invention. Finally, regarding the steps constituting the method according to the present invention, unless explicitly stated in order or otherwise stated, said steps may be performed in a suitable order. The present invention is not necessarily limited by the order in which said steps are described. The use of all examples or exemplary terms (e.g., etc.) in the present invention is merely for the purpose of describing the present invention in detail, and the scope of the present invention is not limited by said examples or exemplary terms unless limited by the claims. Furthermore, those skilled in the art will understand that various modifications, combinations, and changes may be made according to design conditions and factors within the scope of the claims or equivalents to which they are added.

Claims

1. A step of monitoring whether an accident has occurred in the power system of an MVDC electric propulsion vessel; If, as a result of performing the above monitoring, it is detected that an accident has occurred in the power system, a step of determining the type of accident that occurred; A step of determining a protection procedure corresponding to the type of accident determined above; and A method for protecting a power system of an MVDC electric propulsion vessel, comprising the step of performing protection on the power system based on the protection procedure determined above. / As an independent claim, this is a claim that comprehensively describes a configuration for determining the type of fault based on the table shown in FIGS. 6 and FIGS. 7 and appropriately operating a circuit breaker at a specific location accordingly when a fault occurs in the power system of an MVDC electric propulsion vessel.

2. In Paragraph 1, The above protection procedure is, A method for protecting the power system of an MVDC electric propulsion vessel, which is a procedure performed using a multi-use semiconductor switch.

3. In Paragraph 1, The types of accidents that occurred above are, A method for protecting the power system of an MVDC electric propulsion vessel, including the location of the above-mentioned accident.

4. In Paragraph 3, The above occurrence location is, A method for protecting the power system of an MVDC electric propulsion vessel, which is one of a DC bus, an AC generator, a fuel cell, a fuel cell-compatible rectifier, an MMC drive, a permanent magnet motor, a transistor, a transformer, a low-voltage distribution unit (LV SWBD), and a fuel cell converter.

5. In Paragraph 1, The step of determining the above protection procedure is, A power system protection method for an MVDC electric propulsion vessel, determined based on a table matching the location of the accident with the operation of the circuit breaker.

6. In Paragraph 5, The above table is, A method for protecting the power system of an MVDC electric propulsion vessel, comprising a table including detailed settings for a generator, fuel cell, propulsion motor, transformer, and LVAC.

7. In Paragraph 1, The step of determining the above protection procedure is, A method for protecting the power system of an MVDC electric propulsion vessel, wherein, in the event of a fault occurring in an MMC drive constituting the above power system, a first case in which a fault occurs in a submodule and a second case in which a fault occurs in the entire converter are distinguished, and different protection procedures are determined.

8. In Paragraph 1, The step of determining the above protection procedure is, A method for protecting the power system of an MVDC electric propulsion vessel, wherein, in the event of a fault occurring in a fuel cell converter constituting the above power system, a third case in which a fault occurs in a unit rectifier and a fourth case in which a fault occurs in a whole rectifier are distinguished, and different protection procedures are determined.

9. In Paragraph 1, The above MVDC electric propulsion vessel is, Power system protection method for an MVDC electric propulsion vessel based on high voltage direct current (MVDC) for the main distribution section (MSBD) and low voltage alternating current (LVAC) for the secondary distribution section (SSBD).

10. In Paragraph 1, The power supplied to the above power system is, A method for protecting the power system of an MVDC electric propulsion vessel, wherein the power generated by adjusting the driving ratios of a generator, a fuel cell, and an ESS.

11. A computer-readable recording medium storing a program for executing the method according to paragraph 1.

12. Memory in which at least one program is stored; and By executing at least one of the above programs, the processor performs operations, and The above processor is, Monitoring for the occurrence of accidents in the power system of MVDC electric propulsion vessels, and As a result of performing the above monitoring, if it is detected that an accident has occurred in the power system, the type of accident that occurred is determined, and Determine the protection procedure corresponding to the type of accident determined above, and A power system protection device for an MVDC electric propulsion vessel that controls the performance of protection for the power system based on the above-determined protection procedure.

13. In Paragraph 12, The above protection procedure is, A power system protection device for an MVDC electric propulsion vessel, which is a procedure performed using a multi-use semiconductor switch.

14. In Paragraph 13, The above-mentioned multi-use semiconductor switch is, A power system protection device for an MVDC electric propulsion vessel, implemented as a converter or inverter connected to the distribution section of the power system.

15. In Paragraph 12, The above processor is, A power system protection device for an MVDC electric propulsion vessel, which determines based on a table matching the location of the accident with the operation of the circuit breaker.

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