Ship power system whole system short circuit protection design and verification method and test system

Abstract

The invention provides a ship power system whole system short circuit protection design and verification method and a test system, and the method comprises the steps: carrying out the modeling of short circuit current related equipment and cables in a real-time digital simulator according to actual equipment parameters, and forming a digital system of a power system according to an actual power system topological structure; the short-circuit current of each node in a short-circuit fault analysis network is simulated in the system, accurate data support is provided for short-circuit current analysis and short-circuit protection schemes of the power system, and the function of improving the accuracy of calculating the short-circuit current of the ship power system is achieved. A short-circuit protection device needing to be verified in the whole system is connected with the electric power digital system through the real-time digital simulator interface module, short-circuit faults are simulated through all nodes in the digital system, the short-circuit protection scheme of the whole system can be comprehensively verified, the engineering development risk is solved, and the engineering development efficiency is improved. The problems of fine design and test verification of short-circuit protection of a large ship power system are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of ship power system protection, and in particular relates to a design and verification method and a test system for full-system short-circuit protection of a ship power system. Background Art

[0002] Due to damage to ship insulation equipment and human error, ship power systems often fail during operation, resulting in system short circuits. The so-called short circuit in a ship power system refers to a short circuit caused by insulation aging of motors, electrical appliances and cables, or mechanical damage, or abnormal contact of live parts. The large current passing through the fault point is a completely different dangerous state from the overload current generated in the normal state. The ship power system grid operates independently, the power of a single generator set accounts for a large proportion of the system capacity, and the transmission line is short. Therefore, compared with the onshore power system, the ship power system of the same capacity is more affected by short-circuit current. The main reasons include the following aspects: (1) The voltage level of the ship's power system is low, and most loads are directly powered by generators. The power supply line lacks a transformer that can effectively suppress short-circuit current; (2) The distance between the generator and the distribution switches at all levels is relatively close, the line impedance is small, and the ability to suppress short-circuit current is poor; (3) Compared with the generator capacity, the capacity of the motor is relatively large, even close to the capacity of a single generator. In order to pursue good dynamic performance, the role of the damping winding must be strengthened in the design of the marine generator, so the generator feeds a large short-circuit current.

[0003] Short circuit faults may cause fires, damage electrical equipment, and cause the power system to not work properly; even if the power supply equipment is not damaged, excessive short-circuit current may greatly reduce the grid voltage and affect the normal operation of electrical equipment. If the short-circuit fault cannot be eliminated in time, it will cause great damage to the equipment on the fault path, such as generators, cables, buses, circuit breakers, etc. In addition, short circuits may also cause parallel generators to be disconnected, destroying the stability of system operation. In short, short-circuit faults will inevitably have a serious impact on the normal operation of the ship and even endanger the safety of the ship. In order to avoid various faults from damaging the system equipment or destroying the stability of the system operation, short-circuit protection scheme research must be carried out during the development of the power system. Due to the complex network structure of the supply and distribution points of the ship's power system, the short-circuit protection scheme of the power system must ensure that the fault point can be quickly isolated in the smallest area when a short-circuit fault occurs, so as to limit the damage of the short-circuit fault to the minimum range.

[0004] At present, the technical means of studying the short-circuit fault protection scheme of the ship power system is mainly to configure the corresponding protection device on the basis of short-circuit current calculation to ensure that when a short circuit occurs in the power system, the fault can be quickly and effectively cut off and the system can be separated from the fault point. This part of the work is mainly divided into two parts: short-circuit current calculation and protection setting analysis. The short-circuit current calculation uses standard engineering methods to calculate the short-circuit current, and the protection device sets the protection action according to the short-circuit current calculated value at the node where the device is located in the system network structure. This technical means has certain limitations. First, the standard engineering method uses approximate parameters, which makes the calculated value of the short-circuit current have a certain deviation. Secondly, for a more complex network, it is difficult to calculate the short-circuit current at all nodes in the network. Therefore, the traditional short-circuit protection research technical means are relatively extensive, and because the short-circuit current protection test is a destructive test, the short-circuit protection scheme cannot be verified by the whole system, which will bring certain risks to the development of power system engineering. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method and a test system for designing and verifying short-circuit protection of the entire ship power system, which are used to improve the accuracy of calculating the short-circuit current of the ship power system and solve the problem that the short-circuit protection scheme cannot be verified.

[0006] The technical solution adopted by the present invention to solve the above technical problems is: a design and verification method for short-circuit protection of the entire system of a ship power system, comprising the following steps: S1: Establish a digital model of the power system using a real-time digital simulator; S2: Under different working conditions and unit operation modes, simulate short-circuit faults in the power system digital model, analyze the short-circuit current flowing through each node in the power system network when a short-circuit fault occurs, and select and set parameters for the short-circuit protection device of each node; S3: Connect the short-circuit protection device to the node of the power system digital model; S4: Under different working conditions and unit operation modes, short-circuit faults are simulated in the digital model of the power system to verify whether the power system has the function of coordinated protection of all short-circuit protection devices in the whole system, that is, the short-circuit protection device closest to the short-circuit fault point is disconnected, and other short-circuit protection devices do not operate.

[0007] According to the above scheme, in step S1, the specific steps are: S11: Model the short-circuit current equipment based on actual equipment parameters, including generator sets, motors, transformers, and cables; S12: The short-circuit current device model is formed into a power system digital model according to the topological structure of the actual power system network.

[0008] According to the above scheme, in step S2, the operating generator sets in the digital model of the power system are changed to simulate different operating conditions and unit operation modes.

[0009] According to the above scheme, in step S2, S21: Analyze the short-circuit current flowing through each node in the power system network when a short-circuit fault occurs; S22: selecting the short-circuit protection device of each node according to the short-circuit current analysis result; S23: Setting parameters of each short-circuit protection device according to the short-circuit current analysis result.

[0010] Furthermore, in step S22, the parameters of the short-circuit protection device include breaking capacity, action setting value, action time and action return time.

[0011] According to the above scheme, in step S3, the specific steps are: The signal acquisition end of the short-circuit protection device is connected to the analog port of the power system digital model through the power amplifier, and the parameters of the analog port and the power amplifier are matched. The short-circuit protection device collects the short-circuit current of the node where the short-circuit protection device is located in the power system digital model when a short-circuit fault occurs; The auxiliary contact signal interface of the short-circuit protection device is connected to the digital port of the digital model of the power system, and is used to send a control signal to quickly operate and disconnect the circuit when a short-circuit fault occurs.

[0012] Furthermore, in step S3, the network structure of the digital model of the power system is changed by changing the open state or the closed state of the action component of the short-circuit protection device to simulate different power system operation network structures.

[0013] According to the above scheme, in step S4, the specific steps are: S41: short circuit faults are set at different locations of the power system network in the power system digital model; S42: If the short-circuit protection device closest to the short-circuit fault point is disconnected and other short-circuit protection devices do not operate, it is verified that the coordination of the short-circuit protection of the entire system meets the design requirements.

[0014] According to the above scheme, in step S4, the operating generator sets in the digital model of the power system are changed to simulate different operating conditions and unit operation modes.

[0015] A short-circuit protection verification test system for the entire ship power system. A digital model submodule is used to establish a digital model of the power system using a real-time digital simulator; The design submodule is used to simulate short-circuit faults in the digital model of the power system under different working conditions and unit operation modes, analyze the short-circuit current flowing through each node in the power system network when a short-circuit fault occurs, and select and set parameters for the short-circuit protection device of each node; The device-in-the-loop submodule is used to connect the short-circuit protection device to the node of the digital model of the power system; The verification submodule is used to simulate short-circuit faults in the digital model of the power system under different working conditions and unit operation modes, and verify whether the power system has the function of coordinated protection of all short-circuit protection devices in the whole system, that is, the short-circuit protection device closest to the short-circuit fault point is disconnected, and other short-circuit protection devices are not operated.

[0016] The beneficial effects of the present invention are: 1. The present invention provides a method and test system for designing and verifying short-circuit protection of the entire ship power system. By modeling short-circuit current-related equipment and cables according to actual equipment parameters in a real-time digital simulator, and forming a digital system of the power system according to the actual power system topology, the short-circuit current of each node in the short-circuit fault analysis network is simulated in the system, which provides more accurate data support for the short-circuit current analysis and short-circuit protection scheme of the power system, and realizes the function of improving the accuracy of calculating the short-circuit current of the ship power system.

[0017] 2. The present invention utilizes a real-time digital simulator interface module to connect the short-circuit protection device that needs to be verified in the entire system with the power digital system. By simulating short-circuit faults at various nodes in the digital system, the short-circuit protection scheme of the entire system can be fully verified, thereby eliminating engineering development risks and solving the problems of refined design and experimental verification of short-circuit protection in large ship power systems.

[0018] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a schematic diagram of the short-circuit point of the existing ship AC power system.

[0021] Figure 2 It is a schematic block diagram of the principles of an embodiment of the present invention.

[0022] Figure 3is a flow chart of an embodiment of the present invention.

[0023] In the figure: G1, G2, G3, G4: generator sets; MBS1: front main switchboard; MBS2: rear main switchboard; QFx, QF1xx, QF2xx: short-circuit protection devices; DETAILED DESCRIPTION In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] Example 1 See also Figure 3 ,The specific steps of a design and verification method for short-circuit protection of a whole system of a ship power system are as follows: S1: Establish a digital model of the power system using a real-time digital simulator; S2: Under different working conditions and unit operation modes, simulate short-circuit faults in the power system digital model, analyze the short-circuit current flowing through each node in the power system network when a short-circuit fault occurs, and select and set parameters for the short-circuit protection device of each node; S3: Connect the short-circuit protection device to the node of the power system digital model; S4: Under different working conditions and unit operation modes, short-circuit faults are simulated in the digital model of the power system to verify whether the power system has the function of coordinated protection of all short-circuit protection devices in the whole system, that is, the short-circuit protection device closest to the short-circuit fault point is disconnected, and other short-circuit protection devices do not operate.

[0025] Furthermore, in step S1, the specific steps are: S11: Model the short-circuit current equipment based on actual equipment parameters, including generator sets, motors, transformers, and cables; S12: The short-circuit current device model is formed into a power system digital model according to the topological structure of the actual power system network.

[0026] In step S2, the operating generator sets in the digital model of the power system are changed to simulate different operating conditions and unit operation modes.

[0027] In step S2, the specific steps are: S21: Analyze the short-circuit current flowing through each node in the power system network when a short-circuit fault occurs; S22: selecting the short-circuit protection device of each node according to the short-circuit current analysis result; S23: Setting parameters of each short-circuit protection device according to the short-circuit current analysis result.

[0028] Further, in step S22, the parameters of the short-circuit protection device include breaking capacity, action setting value, action time and action return time.

[0029] In step S3, the signal acquisition end of the short-circuit protection device is connected to the analog port of the power system digital model through the power amplifier, the parameters of the analog port and the power amplifier are matched, and the short-circuit protection device collects the short-circuit current of the node where the short-circuit protection device is located in the power system digital model when a short-circuit fault occurs; The auxiliary contact signal interface of the short-circuit protection device is connected to the digital port of the digital model of the power system, and is used to send a control signal to quickly operate and disconnect the circuit when a short-circuit fault occurs.

[0030] Furthermore, in step S3, the network structure of the digital model of the power system is changed by changing the open state or the closed state of the action component of the short-circuit protection device to simulate different power system operation network structures.

[0031] In step S4, the specific steps are: S41: short circuit faults are set at different locations of the power system network in the power system digital model; S42: If the short-circuit protection device closest to the short-circuit fault point is disconnected and other short-circuit protection devices do not operate, it is verified that the coordination of the short-circuit protection of the entire system meets the design requirements.

[0032] In step S4, the operating generator sets in the digital model of the power system are changed to simulate different operating conditions and unit operation modes.

[0033] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0034] This embodiment achieves the function of improving the accuracy of calculating the short-circuit current of the ship power system by modeling the short-circuit current related equipment and cables according to the actual equipment parameters in a real-time digital simulator, and composing a digital system of the power system according to the actual power system topology structure, simulating the short-circuit current of any node in the short-circuit fault analysis network in the system.

[0035] Example 2 The principle of this embodiment is the same as that of Embodiment 1, except that the short-circuit protection device adopts actual equipment.

[0036] Figure 1The diagram is a short-circuit point diagram of a ship's AC power system in the prior art. In the figure, G1, G2, G3 and G4 are all generator sets, and MBS1 and MBS2 are the front and rear main switchboards. G1, G2 and MBS1 are located in the front power station, and G3, G4 and MBS2 are located in the rear power station. The power system distributes and transmits power to power-consuming equipment through cables between distribution equipment such as main switchboards, regional switchboards, load centers and distribution boxes. QF in each distribution equipment is a circuit breaker, that is, a short-circuit protection device.

[0037] Depend on Figure 1 It can be seen that short-circuit protection devices are installed between the generator set and the main distribution board bus, between the bus in the main distribution board, and between the front and rear main distribution boards. Several branches are set in each distribution equipment. For example, QF1xx in MBS1 and QF2xx in MBS2 are short-circuit protection devices on the distribution branches in the main distribution board. Dozens of distribution branches are usually set on each main distribution board, and a series of short-circuit protection devices are set on each distribution branch, such as the two typical distribution branches drawn in the figure: QF21, QF22, QF23 in typical distribution branch one, and QF11, QF12, QF13 in typical distribution branch two.

[0038] The short-circuit protection design of the power system is used to ensure that when a short-circuit fault occurs somewhere in the system, the nearest short-circuit protection device will quickly operate to disconnect the circuit, thereby isolating the fault point in the smallest area and limiting the damage of the short-circuit fault to the minimum scope.

[0039] The design of short-circuit protection for power systems must first analyze how much short-circuit current will occur at each point in the system network if a short circuit occurs. By setting the action setting value and action time of the relevant short-circuit protection device near the point, it is achieved that when a short circuit occurs, the nearest protection device in the network is disconnected while other protection devices do not operate. Figure 1 It can be seen from the simplified diagram of a ship power system that it is quite difficult to analyze the short-circuit current at each point in the system network. First, when a circuit occurs somewhere, the generator set in the network is uncertain. It may be one unit supplying power, or it may be two, three or four units supplying power. Secondly, the short-circuit related parameters (transformer, cable section and length, etc.) corresponding to each point in the network are also different. Therefore, in the past, when designing ship power systems, several typical short-circuit points were usually selected according to the network structure of the system, such as Figure 1As shown in F1~F7, when the maximum unit capacity and the minimum unit capacity are selected, the parameters of each related equipment are used for approximate engineering calculations. This method is used as the basis for setting the action value and action time of the short-circuit protection device. This method is relatively rough. Especially for the complex network of the power system of large ships. Using this method, it is sometimes not possible to isolate the fault point in the smallest area. For example, when F6 in the figure is short-circuited, QF23 is activated, and QF22 and QF21 are also activated. At this time, although only a branch on the distribution box is short-circuited, other branches on the distribution box and other branches on the upper-level regional distribution board are all de-energized. At this time, the network range affected by the fault is expanded.

[0040] This embodiment is provided by attaching Figure 2 The platform combines the digital simulation part and the physical part, uses a real-time digital simulation platform to simulate system operation and faults, and connects the trip device of the circuit breaker that implements protection to the digital simulation platform using actual equipment.

[0041] See also Figure 2 This is a schematic diagram of the principle of this embodiment, which specifically includes two main parts: a platform digital simulation part and a physical part. The platform digital simulation part is a digital model of the power system established using real-time digital data, in which the models of generator sets, motors, transformers, cables, etc. that will affect the short-circuit current are modeled according to actual equipment parameters; the physical part is the trip device of each circuit breaker in the system, which is connected to the corresponding circuit breaker in the platform digital simulation part through a power amplifier.

[0042] The short-circuit protection design of the power system must ensure that when a short-circuit fault occurs somewhere in the system, the nearest short-circuit protection device will quickly operate to disconnect the circuit, thereby isolating the fault point in the smallest area and limiting the damage of the short-circuit fault to the minimum scope.

[0043] The design of short-circuit protection for power systems must first analyze how much short-circuit current will occur at each point in the system network if a short circuit occurs. By setting the action setting value and action time of the relevant short-circuit protection device near the point, it is achieved that when a short circuit occurs, the nearest protection device in the network is disconnected while other protection devices do not operate. Figure 1 It can be seen from the simplified diagram of a ship power system that it is quite difficult to analyze the short-circuit current at each point in the system network. First, when a circuit occurs somewhere, the generator set in the network is uncertain. It may be one unit supplying power, or it may be two, three or four units supplying power. Secondly, the short-circuit related parameters (transformer, cable section and length, etc.) corresponding to each point in the network are also different. Therefore, in the past, when designing ship power systems, several typical short-circuit points were usually selected according to the network structure of the system, such as Figure 1For F1 to F7 shown in the figure, the parameters of the relevant equipment are used for approximate engineering calculations when the maximum unit capacity and the minimum unit capacity are selected. This method is relatively rough to use as the basis for setting the action value and action time of the short-circuit protection device. Especially for the complex network of the power system of large ships. Using this method, it is sometimes not possible to isolate the fault point in the smallest area. For example, when F6 in the figure is short-circuited, QF23 is activated, and QF22 and QF21 are also activated. At this time, although only a branch on the distribution box is short-circuited, other branches on the distribution box and other branches on the upper-level regional distribution board are all de-energized. At this time, the network range affected by the fault is expanded.

[0044] The short-circuit protection design and verification method of the ship complex power system proposed in this embodiment is Figure 2 The platform combines the digital simulation part and the physical part, simulates the system operation and failure using a real-time digital simulation platform, and connects the trip device of the circuit breaker that implements protection to the digital simulation platform using actual equipment.

[0045] The digital simulation part of the platform is a digital model of the power system established using real-time digital technology. The models of generator sets, motors, transformers, cables, etc. that will affect the short-circuit current are modeled according to the steady-state and transient parameters of the actual equipment. Therefore, the digital model of the power system can more realistically reflect the current of each node in the network during normal operation and when a short-circuit fault occurs. By changing the open / closed state of the circuit breaker in the digital model of the power system, the system network structure in the digital model of the power system can be changed to simulate various different system operation network structures; by running the generator sets in the digital model of the power system, the system state of different units in the network can be simulated; short-circuit faults are set at different locations in the system network, and the current values ​​flowing through each node in the network during a short-circuit fault can be calculated in the digital model of the power system, which can provide more accurate data support for the analysis of short-circuit current in the power system.

[0046] Each node in the whole system network needs to be equipped with a short-circuit protection device, and the short-circuit protection has instantaneous action and short-delay action. Select typical nodes in the digital system network of the power system, and analyze and select the breaking capacity, action setting value, action time, action return time and other parameters of each circuit breaker according to the current of each node when a short-circuit fault occurs in various parts of the network under various operating conditions calculated by the digital model of the power system. To form a short-circuit protection plan for the whole system, it should be ensured that the circuit breaker closest to the short-circuit fault point is actuated, and only the circuit breaker closest to the short-circuit fault point is actuated, so as to ensure that when a short-circuit fault occurs, the fault point can be quickly isolated in the smallest area, and the damage of the short-circuit fault is limited to the minimum range.

[0047] The circuit breakers that need to be verified in the short-circuit protection scheme of the whole system are connected to the corresponding circuit breakers in the system digital model in the digital simulation part of the platform, including the sampling current signal input of the trip device of the current flowing through the circuit breaker, and the control signal output of the closing / breaking of the circuit breaker. The I / O analog port of the real-time digital simulator of the corresponding circuit breaker is connected to the voltage / current signal power amplifier. By matching the parameters of the analog port (D / A port) and the power amplifier, the current at the output of the power amplifier is consistent with the sampling current of the circuit breaker trip device in the actual network, so that the circuit breaker trip device obtains the corresponding current signal input; the auxiliary contact signal interface of the circuit breaker itself is connected to the I / O digital port of the corresponding circuit breaker in the real-time digital simulator. At this time, the closing / opening action of the actual circuit breaker can directly control the state of the corresponding circuit breaker in the digital model of the power system.

[0048] This embodiment combines the digital simulation part and the physical part of the platform, and changes the system network structure in the digital model of the power system by operating the actual circuit breaker to simulate various different system operation network structures; simulates the system operation status of different units on the grid by operating the generator sets in the digital model of the power system; sets short-circuit faults at various nodes of the system network to check the matching of all short-circuit protection devices in the short-circuit protection scheme of the whole system, that is, whether the actual short-circuit protection device can ensure that when a short-circuit fault occurs, the protection device closest to the short-circuit fault point will operate, and only the protection device closest to the short-circuit fault point will operate, thereby comprehensively verifying the short-circuit protection scheme of the whole system.

[0049] Example 3 This embodiment is used to implement the principle of the above method embodiment to construct a full-system short-circuit protection verification test system for a ship power system, including a digital model submodule, a design submodule, a device-in-the-loop submodule and a verification submodule.

[0050] A digital model submodule is used to establish a digital model of the power system using a real-time digital simulator; The design submodule is used to simulate short-circuit faults in the digital model of the power system under different working conditions and unit operation modes, analyze the short-circuit current flowing through each node in the power system network when a short-circuit fault occurs, and select and set parameters for the short-circuit protection device of each node; The device-in-the-loop submodule is used to connect the short-circuit protection device to the node of the digital model of the power system; The verification submodule is used to simulate short-circuit faults in the digital model of the power system under different working conditions and unit operation modes, and verify whether the power system has the function of coordinated protection of all short-circuit protection devices in the whole system, that is, the short-circuit protection device closest to the short-circuit fault point is disconnected, and other short-circuit protection devices are not operated.

[0051] Each sub-module is mainly used to implement each step of the method embodiment, which will not be described in detail here.

[0052] It should be pointed out that, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, and two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0053] The above embodiments are only used to illustrate the design ideas and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The protection scope of the present invention is not limited to the above embodiments. Therefore, any equivalent changes or modifications made based on the principles and design ideas disclosed by the present invention are within the protection scope of the present invention.

Claims

1. A method for designing and verifying short-circuit protection of a whole system of a ship power system, characterized in that: The following steps are involved: S1: Establish a digital model of the power system using a real-time digital simulator; S2: Under different working conditions and unit operation modes, short-circuit faults are simulated in the power system digital model, the short-circuit current flowing through each node in the power system network when a short-circuit fault occurs is analyzed, and the short-circuit protection device of each node is selected and parameterized; S3: Connect the short-circuit protection device to the node of the power system digital model; S4: Under different working conditions and unit operation modes, short-circuit faults are simulated in the digital model of the power system to verify whether the power system has the function of coordinated protection of all short-circuit protection devices in the whole system, that is, the short-circuit protection device closest to the short-circuit fault point is disconnected, and other short-circuit protection devices do not operate.

2. A method for designing and verifying short-circuit protection of a whole system of a ship power system according to claim 1, characterized in that: In the step S1, the specific steps are: S11: Model the short-circuit current equipment based on actual equipment parameters, including generator sets, motors, transformers, and cables; S12: The short-circuit current device model is formed into a power system digital model according to the topological structure of the actual power system network.

3. A method for designing and verifying short-circuit protection of a whole system of a ship power system according to claim 1, characterized in that: In step S2, the operating generator sets in the digital model of the power system are changed to simulate different operating conditions and generator set operation modes.

4. A method for designing and verifying short-circuit protection of a whole system of a ship power system according to claim 1, characterized in that: In the step S2, the specific steps are: S21: Analyze the short-circuit current flowing through each node in the power system network when a short-circuit fault occurs; S22: selecting the short-circuit protection device of each node according to the short-circuit current analysis result; S23: Setting parameters of each short-circuit protection device according to the short-circuit current analysis result.

5. A method for designing and verifying short-circuit protection of a whole system of a ship power system according to claim 4, characterized in that: In step S22, the parameters of the short-circuit protection device include breaking capacity, action setting value, action time and action return time.

6. A method for designing and verifying short-circuit protection of a whole system of a ship power system according to claim 1, characterized in that: In the step S3, The signal acquisition end of the short-circuit protection device is connected to the analog port of the power system digital model through the power amplifier, and the parameters of the analog port and the power amplifier are matched. The short-circuit protection device collects the short-circuit current of the node where the short-circuit protection device is located in the power system digital model when a short-circuit fault occurs; The auxiliary contact signal interface of the short-circuit protection device is connected to the digital port of the digital model of the power system, and is used to send a control signal to quickly operate and disconnect the circuit when a short-circuit fault occurs.

7. A method for designing and verifying short-circuit protection of a whole system of a ship power system according to claim 6, characterized in that: In the step S3, the network structure of the digital model of the power system is changed by changing the open state or the closed state of the action component of the short-circuit protection device to simulate different power system operation network structures.

8. A method for designing and verifying short-circuit protection of a whole system of a ship power system according to claim 1, characterized in that: In the step S4, the specific steps are: S41: short circuit faults are set at different locations of the power system network in the power system digital model; S42: If the short-circuit protection device closest to the short-circuit fault point is disconnected and other short-circuit protection devices do not operate, it is verified that the coordination of the short-circuit protection of the entire system meets the design requirements.

9. A method for designing and verifying short-circuit protection of a whole system of a ship power system according to claim 1, characterized in that: In step S4, the operating generator sets in the digital model of the power system are changed to simulate different operating conditions and generator set operation modes.

10. A short-circuit protection verification test system for the entire ship power system, characterized in that: A digital model submodule is used to establish a digital model of the power system using a real-time digital simulator; The design submodule is used to simulate short-circuit faults in the digital model of the power system under different working conditions and unit operation modes, analyze the short-circuit current flowing through each node in the power system network when a short-circuit fault occurs, and select and set parameters for the short-circuit protection device of each node; The device-in-the-loop submodule is used to connect the short-circuit protection device to the node of the digital model of the power system; The verification submodule is used to simulate short-circuit faults in the digital model of the power system under different working conditions and unit operation modes, and verify whether the power system has the function of coordinated protection of all short-circuit protection devices in the whole system, that is, the short-circuit protection device closest to the short-circuit fault point is disconnected, and other short-circuit protection devices are not operated.

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