A method and device for steady-state and transient offline simulation of flexible DC distribution network

Abstract

The present invention relates to the field of power simulation, and discloses a method and device for steady-state and transient offline simulation of a flexible DC distribution network. The present invention establishes a corresponding offline simulation model of the equipment through the action characteristics of each main device of the target flexible distribution network, and establishes an offline steady-state simulation model and an offline transient simulation model based on the simulation model and the change characteristic curve of the target flexible distribution network under each steady-state operating condition and each transient operating condition, and then sets the corresponding offline steady-state simulation plug-in and offline transient simulation plug-in according to the established simulation model, and connects the obtained plug-in with the preset function plug-in using the same backplane switch to obtain a steady-state and transient offline simulation device for a flexible DC distribution network; the offline steady-state simulation plug-in and offline transient simulation plug-in set by the present invention can simulate the transient and steady-state operating conditions of the target flexible distribution network, and the operation and maintenance personnel can perform fault drills and operation training through the simulation device.

Description

Technical Field

[0001] The present invention relates to the technical field of power simulation, and in particular to a method and device for offline simulation of steady-state and transient states of a flexible direct current distribution network. Background Art

[0002] The existing DC distribution network simulation systems are mostly DC current analog test devices and digital-analog hybrid DC transmission simulation devices. The simulation devices mainly use RTDS or RTLAB systems. The system hardware structure is too complex and the cost is relatively high. They are mainly used to study the operating characteristics of DC transmission and distribution, and cannot meet the needs of operation and maintenance personnel in fault drills and operation training. Summary of the invention

[0003] The present invention provides a method and device for offline simulation of steady-state and transient states of a flexible DC distribution network, which solves the technical problem that the existing DC distribution network simulation system cannot meet the needs of operation and maintenance personnel in terms of fault drills and operation training.

[0004] A first aspect of the present invention provides a method for steady-state and transient offline simulation of a flexible DC distribution network, comprising:

[0005] Determine the change characteristic curves of the target flexible distribution network under various steady-state operating conditions and various transient operating conditions, and determine the action characteristics of each major equipment from maintenance, shutdown, cold standby, hot standby to operating state, the change characteristic curves including the AC grid voltage change characteristic curve, the AC grid current change characteristic curve, the DC grid voltage change characteristic curve, and the DC grid current change characteristic curve;

[0006] Establishing a corresponding device offline simulation model according to the action characteristics;

[0007] Establishing an offline steady-state simulation model and an offline transient simulation model corresponding to the target flexible distribution network according to the change characteristic curve and the offline simulation model of the device;

[0008] forming a corresponding offline steady-state simulation plug-in based on the offline steady-state simulation model, and forming a corresponding offline transient simulation plug-in based on the offline transient simulation model;

[0009] The same backplane switch is used to connect the offline steady-state simulation plug-in, the offline transient simulation plug-in and the preset function plug-in to obtain a steady-state and transient offline simulation device for a flexible DC distribution network; the preset function plug-in includes an input-output plug-in and a control plug-in, the input-output plug-in is used to receive simulation control instructions for the offline steady-state simulation plug-in and / or the offline transient simulation plug-in; the control plug-in is used to control the start or lock of the offline steady-state simulation plug-in and the offline transient simulation plug-in according to the simulation results of the offline steady-state simulation plug-in and the offline transient simulation plug-in.

[0010] According to an achievable method of the first aspect of the present invention, the determination of the change characteristic curve of the target flexible distribution network under each steady-state operating condition and each transient operating condition, and the determination of the action characteristics of each major equipment from maintenance, shutdown, cold standby, hot standby to operating state include:

[0011] The change characteristic curve and the action characteristic are determined according to simulation data of the target flexible distribution network by a DC current analog test device and / or a digital-analog hybrid DC power transmission simulation device.

[0012] According to an achievable manner of the first aspect of the present invention, the establishing of a corresponding device offline simulation model includes:

[0013] Determine that the main equipment corresponding to the maintenance-shutdown-cold standby state includes ground switches, isolation switches and switches, and establish a first equipment offline simulation model corresponding to the maintenance-shutdown-cold standby state according to the corresponding action characteristics.

[0014] According to an achievable manner of the first aspect of the present invention, the establishing of a corresponding device offline simulation model further includes:

[0015] Determine that the main equipment corresponding to the cold standby-hot standby-operation state includes a DC converter valve, a DC transformer and an AC circuit breaker, and establish an offline simulation model of the second equipment corresponding to the cold standby-hot standby-operation state according to the corresponding action characteristics.

[0016] According to an achievable manner of the first aspect of the present invention, the establishing of a corresponding device offline simulation model further includes:

[0017] The first device offline simulation model and / or the second device offline simulation model are formed by combining a set-reset trigger and an on-delay device.

[0018] A second aspect of the present invention provides a flexible DC distribution network steady-state and transient offline simulation device, comprising an offline steady-state simulation plug-in, an offline transient simulation plug-in, an input-output plug-in, and a control plug-in, wherein the offline steady-state simulation plug-in, the offline transient simulation plug-in, the input-output plug-in, and the control plug-in are connected via the same backplane switch;

[0019] The offline steady-state simulation plug-in is configured with an offline steady-state simulation model; the offline steady-state simulation model is constructed based on the change characteristic curves of the target flexible distribution network under various steady-state operating conditions and various transient operating conditions, and the equipment offline simulation model corresponding to each major equipment; the equipment offline simulation model is constructed based on the action characteristics of the corresponding major equipment from maintenance, shutdown, cold standby, hot standby to operating state; the change characteristic curves include AC grid voltage change characteristic curves, AC grid current change characteristic curves, DC grid voltage change characteristic curves, and DC grid current change characteristic curves;

[0020] The offline transient simulation plug-in is configured with an offline steady-state simulation model; the offline steady-state simulation model is constructed based on the change characteristic curve and the device offline simulation model;

[0021] The input / output plug-in is used to receive simulation control instructions for the offline steady-state simulation plug-in and / or the offline transient simulation plug-in;

[0022] The control plug-in is used to control the start or lock of the offline steady-state simulation plug-in and the offline transient simulation plug-in according to the simulation results of the offline steady-state simulation plug-in and the offline transient simulation plug-in.

[0023] According to an achievable manner of the second aspect of the present invention, the device offline simulation model corresponding to each major device includes:

[0024] An offline simulation model of the first equipment corresponding to the maintenance-outage-cold standby state;

[0025] Among them, the offline simulation model of the first equipment includes a ground switch simulation model established according to the action characteristics of the ground switch in the maintenance-shutdown-cold standby state, a partition knife simulation model established according to the action characteristics of the partition knife in the maintenance-shutdown-cold standby state, and a switch simulation model established according to the action characteristics of the switch in the maintenance-shutdown-cold standby state.

[0026] According to an achievable manner of the second aspect of the present invention, the device offline simulation model corresponding to each main device further includes:

[0027] An offline simulation model of a second device corresponding to a cold standby-hot standby-running state;

[0028] Among them, the offline simulation model of the second device includes a DC converter valve simulation model established according to the action characteristics of the DC converter valve in the cold standby-hot standby-operating state, a DC transformer simulation model established according to the action characteristics of the DC transformer in the cold standby-hot standby-operating state, and an AC circuit breaker simulation model established according to the action characteristics of the AC circuit breaker in the cold standby-hot standby-operating state.

[0029] According to an achievable manner of the second aspect of the present invention, the first device offline simulation model and / or the second device offline simulation model is formed by combining a set-reset trigger and an on-delay device.

[0030] According to an achievable manner of the second aspect of the present invention, the offline steady-state simulation plug-in, the offline transient simulation plug-in, the input-output plug-in and the control plug-in exchange information through the GOOSE protocol.

[0031] It can be seen from the above technical solutions that the present invention has the following advantages:

[0032] The present invention establishes a corresponding equipment offline simulation model through the action characteristics of each main equipment of the target flexible distribution network from maintenance, shutdown, cold standby, hot standby to operation state, and based on the equipment offline simulation model and the change characteristic curve of the target flexible distribution network under each steady-state operation condition and each transient operation condition, establishes an offline steady-state simulation model and an offline transient simulation model corresponding to the target flexible distribution network, and then sets the corresponding offline steady-state simulation plug-in and offline transient simulation plug-in according to the established simulation model, and uses the same backplane switch to connect the obtained plug-in with the preset function plug-in to obtain a steady-state and transient offline simulation device for the flexible DC distribution network; the present invention sets the simulation device in the form of a plug-in, which has a simple structure, and the set offline steady-state simulation plug-in and offline transient simulation plug-in can simulate the transient and steady-state operation conditions of the target flexible distribution network, and the operation and maintenance personnel can perform fault drills and operation training through the simulation device. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0034] Figure 1 A flowchart of a method for steady-state and transient offline simulation of a flexible DC distribution network provided by an optional embodiment of the present invention;

[0035] Figure 2A schematic diagram of a device offline simulation model function established by a set-reset trigger and an on-delay device provided in an optional embodiment of the present invention;

[0036] Figure 3 A structural connection block diagram of a flexible DC distribution network steady-state and transient offline simulation device provided by an optional embodiment of the present invention. Description of the drawings:

[0038] 1-Offline steady-state simulation plug-in; 2-Offline transient simulation plug-in; 3-Input and output plug-in; 4-Control plug-in; 5-Backplane switch. DETAILED DESCRIPTION

[0039] The embodiment of the present invention provides a method and device for steady-state and transient offline simulation of a flexible DC distribution network, which is used to solve the technical problem that the existing DC distribution network simulation system cannot meet the needs of operation and maintenance personnel in fault drills and operation training.

[0040] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] The present invention provides a method for offline simulation of a flexible DC distribution network in steady state and transient state.

[0042] See also Figure 1 , Figure 1 A flow chart of a method for steady-state and transient offline simulation of a flexible DC distribution network provided by an embodiment of the present invention is shown.

[0043] The embodiment of the present invention provides a method for offline simulation of a flexible DC distribution network in steady state and transient state, comprising steps S1-S5.

[0044] Step S1, determine the change characteristic curves of the target flexible distribution network under various steady-state operating conditions and various transient operating conditions, and determine the action characteristics of each major equipment from maintenance, shutdown, cold standby, hot standby to operating state, the change characteristic curves include AC grid voltage change characteristic curve, AC grid current change characteristic curve, DC grid voltage change characteristic curve, DC grid current change characteristic curve.

[0045] The dynamic characteristics include the closing action sequence, opening action sequence, closing action duration, opening action duration and stateless duration of the main equipment. The steady-state operating condition includes the corresponding operating conditions of the target flexible DC distribution network when it is in double-terminal operation, three-terminal operation, black start, different power, unlocking and / or locking. The transient operating condition includes AC side fault, DC side fault and / or permanent fault. Specifically, the steady-state operating condition and transient operating condition to be simulated can be determined according to the training needs.

[0046] The target flexible distribution network is a flexible distribution network to be simulated. The change characteristic curves and the action characteristics of each main device can be obtained according to the actual operation data analysis of the target flexible distribution network.

[0047] In other embodiments, the change characteristic curve and the action characteristic may also be determined based on simulation data of the target flexible distribution network by a DC current analog test device and / or a digital-analog hybrid DC power transmission simulation device.

[0048] As existing equipment, DC current analog test devices and digital-analog hybrid DC transmission simulation devices are mainly used to study the operating characteristics of DC transmission and distribution. Based on this feature, the simulation data of the target flexible distribution network can be used by the DC current analog test device and / or the digital-analog hybrid DC transmission simulation device to obtain the required change characteristic curves and the action characteristic data of each major equipment more conveniently.

[0049] Step S2: establishing a corresponding device offline simulation model according to the action characteristics.

[0050] In one achievable manner, the establishing of a corresponding device offline simulation model includes:

[0051] Determine that the main equipment corresponding to the maintenance-shutdown-cold standby state includes ground switches, isolation switches and switches, and establish a first equipment offline simulation model corresponding to the maintenance-shutdown-cold standby state according to the corresponding action characteristics.

[0052] Since the main equipment involved in the maintenance-shutdown-cold standby state is the grounding knife, the isolation knife and the switch, the embodiment of the present invention establishes an offline simulation model of the first equipment according to the corresponding action characteristics of the grounding knife, the isolation knife and the switch.

[0053] In one achievable manner, the establishing of the corresponding device offline simulation model further includes:

[0054] Determine that the main equipment corresponding to the cold standby-hot standby-operation state includes a DC converter valve, a DC transformer and an AC circuit breaker, and establish an offline simulation model of the second equipment corresponding to the cold standby-hot standby-operation state according to the corresponding action characteristics.

[0055] Since the main devices involved in the cold standby-hot standby-operation state are the DC converter valve, the DC transformer and the AC circuit breaker, the embodiment of the present invention establishes an offline simulation model of the second device according to the corresponding action characteristics of the DC converter valve, the DC transformer and the AC circuit breaker.

[0056] In one achievable manner, the establishing of the corresponding device offline simulation model further includes:

[0057] The first device offline simulation model and / or the second device offline simulation model are formed by combining a set-reset trigger and an on-delay device.

[0058] In specific implementation, for each device offline simulation model, the following can be established by setting the reset trigger and connecting the delay device: Figure 2 The device offline simulation model function is shown. Figure 2 In the figure, RS represents the set-reset trigger; TON represents the on-delay device; CL_ORD represents the closing command, OP_ORD represents the opening command, CL_IND represents the closing state, OP_IND represents the opening state, and T represents the dynamic characteristic time of the equipment.

[0059] Step S3, establishing an offline steady-state simulation model and an offline transient simulation model corresponding to the target flexible distribution network according to the change characteristic curve and the device offline simulation model.

[0060] Step S4: forming a corresponding offline steady-state simulation plug-in based on the offline steady-state simulation model, and forming a corresponding offline transient simulation plug-in based on the offline transient simulation model.

[0061] Step S5, using the same backplane switch, connecting the offline steady-state simulation plug-in, the offline transient simulation plug-in and the preset function plug-in to obtain a flexible DC distribution network steady-state and transient offline simulation device; the preset function plug-in includes an input-output plug-in and a control plug-in, the input-output plug-in is used to receive simulation control instructions for the offline steady-state simulation plug-in and / or the offline transient simulation plug-in; the control plug-in is used to control the start or lock of the offline steady-state simulation plug-in and the offline transient simulation plug-in according to the simulation results of the offline steady-state simulation plug-in and the offline transient simulation plug-in.

[0062] The present invention also provides a flexible DC distribution network steady-state and transient off-line simulation device.

[0063] See also Figure 3 , Figure 3 A structural connection block diagram of a flexible DC distribution network steady-state and transient offline simulation device provided by an embodiment of the present invention is shown.

[0064] The flexible DC distribution network steady-state and transient offline simulation device provided by the embodiment of the present invention comprises an offline steady-state simulation plug-in 1, an offline transient simulation plug-in 2, an input-output plug-in 3 and a control plug-in 4, wherein the offline steady-state simulation plug-in 1, the offline transient simulation plug-in 2, the input-output plug-in 3 and the control plug-in 4 are connected via the same backplane switch 5;

[0065] The offline steady-state simulation plug-in 1 is configured with an offline steady-state simulation model; the offline steady-state simulation model is constructed based on the change characteristic curves of the target flexible distribution network under various steady-state operating conditions and various transient operating conditions, and the offline simulation model of the equipment corresponding to each major equipment; the equipment offline simulation model is constructed based on the action characteristics of the corresponding major equipment from maintenance, shutdown, cold standby, hot standby to operating state; the change characteristic curves include AC grid voltage change characteristic curves, AC grid current change characteristic curves, DC grid voltage change characteristic curves, and DC grid current change characteristic curves;

[0066] The offline transient simulation plug-in 2 is configured with an offline steady-state simulation model; the offline steady-state simulation model is constructed based on the change characteristic curve and the device offline simulation model;

[0067] The input-output plug-in 3 is used to receive simulation control instructions for the offline steady-state simulation plug-in 1 and / or the offline transient simulation plug-in 2;

[0068] The control plug-in 4 is used to control the start or lock of the offline steady-state simulation plug-in 1 and the offline transient simulation plug-in 2 according to the simulation results of the offline steady-state simulation plug-in 1 and the offline transient simulation plug-in 2.

[0069] In one achievable manner, the device offline simulation model corresponding to each major device includes:

[0070] An offline simulation model of the first equipment corresponding to the maintenance-outage-cold standby state;

[0071] Among them, the offline simulation model of the first equipment includes a ground switch simulation model established according to the action characteristics of the ground switch in the maintenance-shutdown-cold standby state, a partition knife simulation model established according to the action characteristics of the partition knife in the maintenance-shutdown-cold standby state, and a switch simulation model established according to the action characteristics of the switch in the maintenance-shutdown-cold standby state.

[0072] In one achievable manner, the device offline simulation model corresponding to each major device further includes:

[0073] An offline simulation model of a second device corresponding to a cold standby-hot standby-running state;

[0074] Among them, the offline simulation model of the second device includes a DC converter valve simulation model established according to the action characteristics of the DC converter valve in the cold standby-hot standby-operating state, a DC transformer simulation model established according to the action characteristics of the DC transformer in the cold standby-hot standby-operating state, and an AC circuit breaker simulation model established according to the action characteristics of the AC circuit breaker in the cold standby-hot standby-operating state.

[0075] In one achievable manner, the first device offline simulation model and / or the second device offline simulation model is formed by combining a set-reset trigger and an on-delay device.

[0076] In one achievable manner, the offline steady-state simulation plug-in 1, the offline transient simulation plug-in 2, the input-output plug-in 3 and the control plug-in 4 perform information exchange through the GOOSE protocol.

[0077] The GOOSE protocol is a mechanism in the IEC 61850 standard used to meet the fast message requirements of the substation automation system. The information exchange between plug-ins through the GOOSE protocol can ensure the reliability of information exchange.

[0078] When operation and maintenance personnel conduct simulation training through the steady-state and transient offline simulation device of the flexible DC distribution network, they can input control instructions through the interface of the input-output plug-in 3. For example, a first control instruction about steady-state operation is input, and the first control instruction includes a steady-state target setting value, such as an active power threshold. When the offline steady-state simulation plug-in 1 receives the first control instruction, it simulates the voltage and current analog information of the DC distribution network according to the first control instruction, and simulates the characteristics of equipment such as DC circuit breakers, DC converters, grounding switches, isolation switches, and switches to achieve the simulation of the operating condition with active power being the active power threshold. The offline steady-state simulation plug-in 1 transmits the simulation data to other functional plug-ins through the backplane switch 5.

[0079] For another example, a second control instruction about transient operation is input, and the second control instruction is an instruction for simulating a target fault. The offline transient simulation plug-in 2 simulates the voltage and current analog information of the DC distribution network under the corresponding fault of the DC distribution network according to the second control instruction, and simulates the characteristics of equipment such as DC circuit breakers, DC converters, grounding knives, isolation knives, switches, etc., and transmits them to other functional plug-ins through the backplane switch 5. When the control plug-in 4 determines that the current state of the flexible DC distribution network is a fault state based on the simulation data output by the offline steady-state simulation plug-in 1 or the offline transient simulation plug-in 2, the offline steady-state simulation plug-in 1 is locked, and after the fault is cleared, the offline steady-state simulation plug-in 1 is started.

[0080] It should be noted that in order to improve the effect of simulation training, the flexible DC distribution network steady-state and transient offline simulation device of the above embodiment of the present invention can also add other functional plug-ins, such as a communication plug-in for communicating with a remote terminal, a storage plug-in for storing simulation data, etc.

[0081] In the above-mentioned embodiment of the present invention, a corresponding equipment offline simulation model is established through the action characteristics of each main equipment of the target flexible distribution network from maintenance, shutdown, cold standby, hot standby to operation state, and based on the equipment offline simulation model and the change characteristic curve of the target flexible distribution network under each steady-state operating condition and each transient operating condition, an offline steady-state simulation model and an offline transient simulation model corresponding to the target flexible distribution network are established, and then a corresponding offline steady-state simulation plug-in and an offline transient simulation plug-in are set according to the established simulation model, and the obtained plug-in is connected with the preset function plug-in using the same backplane switch to obtain a steady-state and transient offline simulation device for a flexible DC distribution network; the present invention sets the simulation device in the form of a plug-in, and the structure is simple. The set offline steady-state simulation plug-in and offline transient simulation plug-in can simulate the transient and steady-state operating conditions of the target flexible distribution network, and the operation and maintenance personnel can perform fault drills and operation training through the simulation device.

[0082] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for steady-state and transient offline simulation of a flexible DC distribution network, characterized in that: include: Determine the change characteristic curves of the target flexible distribution network under various steady-state operating conditions and various transient operating conditions, and determine the action characteristics of each major equipment from maintenance, shutdown, cold standby, hot standby to operating state, the change characteristic curves including the AC grid voltage change characteristic curve, the AC grid current change characteristic curve, the DC grid voltage change characteristic curve, and the DC grid current change characteristic curve; Establishing a corresponding device offline simulation model according to the action characteristics; Establishing an offline steady-state simulation model and an offline transient simulation model corresponding to the target flexible distribution network according to the change characteristic curve and the offline simulation model of the device; forming a corresponding offline steady-state simulation plug-in based on the offline steady-state simulation model, and forming a corresponding offline transient simulation plug-in based on the offline transient simulation model; The same backplane switch is used to connect the offline steady-state simulation plug-in, the offline transient simulation plug-in and the preset function plug-in to obtain a flexible DC distribution network steady-state and transient offline simulation device; The preset function plug-in includes an input / output plug-in and a control plug-in. The input / output plug-in is used to receive simulation control instructions for the offline steady-state simulation plug-in and / or the offline transient simulation plug-in; the control plug-in is used to control the start or lock of the offline steady-state simulation plug-in and the offline transient simulation plug-in according to the simulation results of the offline steady-state simulation plug-in and the offline transient simulation plug-in.

2. The method for steady-state and transient offline simulation of a flexible DC distribution network according to claim 1, characterized in that: The determination of the change characteristic curve of the target flexible distribution network under each steady-state operating condition and each transient operating condition, and the determination of the action characteristics of each major equipment from maintenance, shutdown, cold standby, hot standby to operating state, include: The change characteristic curve and the action characteristic are determined according to simulation data of the target flexible distribution network by a DC current analog test device and / or a digital-analog hybrid DC power transmission simulation device.

3. The method for steady-state and transient offline simulation of a flexible DC distribution network according to claim 1, characterized in that: The establishing of the corresponding device offline simulation model includes: Determine that the main equipment corresponding to the maintenance-shutdown-cold standby state includes ground switches, isolation switches and switches, and establish a first equipment offline simulation model corresponding to the maintenance-shutdown-cold standby state according to the corresponding action characteristics.

4. The method for steady-state and transient offline simulation of a flexible DC distribution network according to claim 3 is characterized in that: The establishing of the corresponding device offline simulation model also includes: Determine that the main equipment corresponding to the cold standby-hot standby-operation state includes a DC converter valve, a DC transformer and an AC circuit breaker, and establish an offline simulation model of the second equipment corresponding to the cold standby-hot standby-operation state according to the corresponding action characteristics.

5. The method for steady-state and transient offline simulation of a flexible DC distribution network according to claim 4, characterized in that: The establishing of the corresponding device offline simulation model also includes: The first device offline simulation model and / or the second device offline simulation model are formed by combining a set-reset trigger and an on-delay device.

6. A steady-state and transient offline simulation device for a flexible DC distribution network, characterized in that: It includes an offline steady-state simulation plug-in, an offline transient simulation plug-in, an input-output plug-in and a control plug-in, wherein the offline steady-state simulation plug-in, the offline transient simulation plug-in, the input-output plug-in and the control plug-in are connected via the same backplane switch; The offline steady-state simulation plug-in is configured with an offline steady-state simulation model; the offline steady-state simulation model is constructed based on the change characteristic curves of the target flexible distribution network under various steady-state operating conditions and various transient operating conditions, and the equipment offline simulation model corresponding to each major equipment; the equipment offline simulation model is constructed based on the action characteristics of the corresponding major equipment from maintenance, shutdown, cold standby, hot standby to operating state; the change characteristic curves include AC grid voltage change characteristic curves, AC grid current change characteristic curves, DC grid voltage change characteristic curves, and DC grid current change characteristic curves; The offline transient simulation plug-in is configured with an offline steady-state simulation model; the offline steady-state simulation model is constructed based on the change characteristic curve and the device offline simulation model; The input / output plug-in is used to receive simulation control instructions for the offline steady-state simulation plug-in and / or the offline transient simulation plug-in; The control plug-in is used to control the start or lock of the offline steady-state simulation plug-in and the offline transient simulation plug-in according to the simulation results of the offline steady-state simulation plug-in and the offline transient simulation plug-in.

7. The device for steady-state and transient offline simulation of a flexible DC distribution network according to claim 6, characterized in that: The device offline simulation model corresponding to each major device includes: An offline simulation model of the first equipment corresponding to the maintenance-outage-cold standby state; Among them, the offline simulation model of the first equipment includes a ground switch simulation model established according to the action characteristics of the ground switch in the maintenance-shutdown-cold standby state, a partition knife simulation model established according to the action characteristics of the partition knife in the maintenance-shutdown-cold standby state, and a switch simulation model established according to the action characteristics of the switch in the maintenance-shutdown-cold standby state.

8. The device for steady-state and transient offline simulation of a flexible DC distribution network according to claim 7, characterized in that: The device offline simulation model corresponding to each major device also includes: An offline simulation model of a second device corresponding to a cold standby-hot standby-running state; Among them, the offline simulation model of the second device includes a DC converter valve simulation model established according to the action characteristics of the DC converter valve in the cold standby-hot standby-operating state, a DC transformer simulation model established according to the action characteristics of the DC transformer in the cold standby-hot standby-operating state, and an AC circuit breaker simulation model established according to the action characteristics of the AC circuit breaker in the cold standby-hot standby-operating state.

9. The device for steady-state and transient offline simulation of a flexible DC distribution network according to claim 8, characterized in that: The first device offline simulation model and / or the second device offline simulation model are formed by combining a set-reset trigger and an on-delay device.

10. The device for steady-state and transient offline simulation of a flexible DC distribution network according to any one of claims 6 to 9, characterized in that: The offline steady-state simulation plug-in, offline transient simulation plug-in, input-output plug-in and control plug-in perform information exchange through the GOOSE protocol.

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