Method and device for optimizing insulation level of extra-high voltage flexible direct current power transmission system, and computer equipment

Abstract

The invention relates to the technical field of electrical insulation, and provides a method and a device for optimizing the insulation level of an extra-high voltage flexible direct current power transmission system, and computer equipment. The method comprises the steps of obtaining an overvoltage simulation program of key equipment in each operation mode according to topology, equipment parameters and a control protection strategy of the extra-high voltage flexible direct current power transmission system; according to the overvoltage simulation program, carrying out simulation analysis on the key measuring points of the converter station under each fault working condition to obtain overvoltage data, sub-module blocking time and lightning arrester configuration schemes of the key measuring points of the converter station under each fault working condition so as to obtain an entity relation graph; and obtaining an overvoltage simulation database according to the entity relation graph so as to obtain a strong association rule among the overvoltage state change, the sub-module blocking time and the lightning arrester configuration scheme, and optimizing the insulation level of the extra-high voltage flexible direct current power transmission system according to the strong association rule. By adopting the method, the optimization degree of the insulation level of the extra-high voltage flexible direct current power transmission system can be improved.

Description

Technical Field

[0001] The present application relates to the field of electrical insulation technology, and in particular to a method, device, computer equipment, computer-readable storage medium and computer program product for optimizing the insulation level of an ultra-high voltage flexible direct current transmission system. Background Art

[0002] UHV flexible DC transmission systems are widely used due to their advantages such as high efficiency, long-distance transmission and low loss, but their insulation systems must have sufficient electrical strength to withstand high voltages and cope with the impact of environmental factors on their performance. Especially in high-altitude areas, as the atmospheric pressure decreases, the insulation performance of air decreases significantly, so a larger air clearance and higher construction costs are required to ensure the insulation reliability of the system. Optimizing the insulation level of UHV flexible DC transmission systems is of great significance for preventing insulation breakdown, improving the stability and reliability of system operation, and reducing long-term maintenance costs. At present, the insulation coordination scheme of similar projects to the UHV flexible DC transmission system can be used as a reference to determine the insulation scheme of the UHV flexible DC transmission system. However, this method does not refer to specific UHV flexible DC transmission system data, and the degree of optimization of the insulation level of the UHV flexible DC transmission system is relatively small. Summary of the invention

[0003] Based on this, it is necessary to provide a method, device, computer equipment, computer-readable storage medium and computer program product for optimizing the insulation level of a UHV flexible direct current transmission system in response to the above-mentioned technical problems.

[0004] In a first aspect, the present application provides a method for optimizing the insulation level of an ultra-high voltage flexible direct current transmission system, comprising:

[0005] According to the topology, equipment parameters and control protection strategy of the UHV flexible DC transmission system, the overvoltage simulation program of key equipment under each operation mode is obtained;

[0006] According to the overvoltage simulation program, simulation analysis of key measuring points of the converter station under various fault conditions is performed to obtain overvoltage data, submodule locking time and arrester configuration scheme of key measuring points of the converter station under various fault conditions;

[0007] According to the overvoltage data of the key measuring points of the converter station under each fault condition, the submodule locking time and the arrester configuration scheme, an entity relationship diagram is obtained;

[0008] According to the entity relationship diagram, an overvoltage simulation database is obtained;

[0009] According to the overvoltage simulation database, a strong association rule between the overvoltage state change and the submodule locking time and the arrester configuration scheme is obtained, so as to optimize the insulation level of the ultra-high voltage flexible direct current transmission system according to the strong association rule.

[0010] In one embodiment, the entity relationship diagram is obtained according to the overvoltage data of the key measuring points of the converter station under each fault condition, the submodule locking time and the arrester configuration scheme, including:

[0011] The overvoltage data of the key measuring points are used as the simulation results obtained by simulating the key measuring points;

[0012] The submodule blocking time and arrester configuration scheme of key measuring points are used as simulation settings of key measuring points;

[0013] Taking key measuring points, simulation results obtained by simulating the key measuring points, and simulation settings of the key measuring points as entities, and assigning key attributes and descriptive attributes to each entity;

[0014] The key measuring points are taken as the main table, the simulation results obtained by simulating the key measuring points and the simulation settings of the key measuring points are taken as sub-tables, and inter-table associations are established between the key measuring point main table and the simulation result sub-table and the simulation setting sub-table to obtain an entity relationship diagram.

[0015] In one embodiment, obtaining an overvoltage simulation database according to the entity relationship diagram includes:

[0016] According to the entity relationship diagram, the relationship model of the key measurement point main table is obtained;

[0017] Get the data types of the key measurement point main table, simulation result sub-table and simulation setting sub-table;

[0018] An overvoltage simulation database is obtained according to the relational model of the key measuring point main table and the data types of each table.

[0019] In one embodiment, the strong association rule between the overvoltage state change and the submodule locking time and the arrester configuration scheme is obtained according to the overvoltage simulation database, including:

[0020] Performing data processing on the overvoltage simulation database and constructing a correlation analysis database; each record of the correlation analysis database includes a state mark of the overvoltage state, adjustment information of the submodule locking time and adjustment information of the arrester configuration scheme;

[0021] According to the set minimum support, the association analysis database is scanned multiple times to obtain a number of frequent item sets; the frequent item sets include overvoltage state change information exceeding the set minimum support, submodule locking time adjustment information and lightning arrester configuration scheme;

[0022] Calculate the confidence between several frequent item sets;

[0023] According to the set minimum confidence, the strong correlation rules between the overvoltage state change and the submodule blocking time and the arrester configuration scheme are obtained.

[0024] In one embodiment, the overvoltage data includes an overvoltage amplitude and an overvoltage waveform, and the overvoltage simulation database is processed to construct a correlation analysis database, including:

[0025] According to the median of the overvoltage amplitude at each key measuring point, the overvoltage amplitude limit is obtained;

[0026] According to the overvoltage amplitude limit, the overvoltage states in the overvoltage simulation database are divided into three categories, so as to determine the state mark of the overvoltage state according to the category of the overvoltage state in the overvoltage simulation database;

[0027] When the lockout time of the submodule in the overvoltage simulation database is adjusted upward, determining the adjustment information of the lockout time of the submodule as a first adjustment mark;

[0028] When the lockout time of the submodule in the overvoltage simulation database is adjusted downward, determining the adjustment information of the lockout time of the submodule to be a second adjustment mark;

[0029] According to the scheme category to which the lightning arrester configuration scheme in the overvoltage simulation database belongs, adjustment information of the lightning arrester configuration scheme is obtained;

[0030] The state mark of the overvoltage state having an associated relationship, the adjustment information of the submodule blocking time and the adjustment information of the arrester configuration scheme are taken as a record to obtain an associated analysis database.

[0031] In one of the embodiments, the key measuring points include at least one of a converter transformer grid side measuring point, a converter transformer valve side measuring point, a valve bottom to ground measuring point, a valve top to ground measuring point, a DC line to ground measuring point, a neutral busbar measuring point, a valve end measuring point, and a DC reactor end voltage measuring point.

[0032] In a second aspect, the present application also provides an optimization device for the insulation level of a UHV flexible DC transmission system, comprising:

[0033] The simulation program acquisition module is used to obtain the overvoltage simulation program of key equipment under various typical operation modes according to the topology, equipment parameters and control protection strategy of the UHV flexible DC transmission system;

[0034] A simulation analysis module, used to perform simulation analysis of key measuring points of the converter station under various fault conditions according to the overvoltage simulation program, and obtain overvoltage data, submodule locking time and arrester configuration scheme of key measuring points of the converter station under various fault conditions;

[0035] An entity relationship diagram acquisition module is used to obtain an entity relationship diagram according to the overvoltage data of key measuring points of the converter station under each fault condition, the submodule locking time and the arrester configuration scheme;

[0036] A simulation database acquisition module, used to obtain an overvoltage simulation database according to the entity relationship diagram;

[0037] The strong association rule acquisition module is used to: obtain the strong association rules between the overvoltage state change and the submodule locking time and the lightning arrester configuration scheme according to the overvoltage simulation database, so as to optimize the insulation level of the ultra-high voltage flexible direct current transmission system according to the strong association rules.

[0038] In a third aspect, the present application further provides a computer device, wherein the computer device comprises a memory and a processor, wherein the memory stores a computer program, and the processor executes the above method.

[0039] In a fourth aspect, the present application further provides a computer-readable storage medium, wherein a computer program is stored on the computer-readable storage medium, and the computer program is executed by a processor to execute the above method.

[0040] In a fifth aspect, the present application further provides a computer program product, wherein the computer program product comprises a computer program, and the computer program is executed by a processor to execute the above method.

[0041] The above-mentioned method, device, computer equipment, computer-readable storage medium and computer program product for optimizing the insulation level of the ultra-high voltage flexible direct current transmission system obtain an overvoltage simulation program for key equipment under each operating mode according to the topology, equipment parameters and control protection strategy of the ultra-high voltage flexible direct current transmission system; according to the overvoltage simulation program, simulation analysis of key measuring points of the converter station under each fault condition is performed to obtain overvoltage data, submodule locking time and lightning arrester configuration scheme of the key measuring points of the converter station under each fault condition; according to the overvoltage data, submodule locking time and lightning arrester configuration scheme of the key measuring points of the converter station under each fault condition, an entity relationship diagram is obtained; according to the entity relationship diagram, an overvoltage simulation database is obtained; according to the overvoltage simulation database, a strong association rule between the overvoltage state change and the submodule locking time and lightning arrester configuration scheme is obtained, so as to optimize the insulation level of the ultra-high voltage flexible direct current transmission system according to the strong association rule. When determining the insulation scheme of the UHV flexible DC transmission system, the present application refers to the overvoltage data of key measuring points of the converter station under various fault conditions of the UHV flexible DC transmission system, the submodule locking time and the arrester configuration scheme data, and obtains an overvoltage simulation database; based on the overvoltage simulation database, a strong correlation rule between the overvoltage state change and the submodule locking time and the arrester configuration scheme is obtained, and based on the strong correlation rule, the insulation level of the UHV flexible DC transmission system is optimized, thereby improving the degree of optimization of the insulation level of the UHV flexible DC transmission system. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0043] Figure 1 A diagram showing an application environment of a method for optimizing the insulation level of a UHV flexible direct current transmission system in one embodiment;

[0044] Figure 2 It is a flow chart of a method for optimizing the insulation level of an ultra-high voltage flexible direct current transmission system in one embodiment;

[0045] Figure 3 is an entity relationship diagram in one embodiment;

[0046] Figure 4 Another form of entity relationship diagram in one embodiment;

[0047] Figure 5 A schematic diagram of a lightning arrester configuration scheme in one embodiment;

[0048] Figure 6 is a schematic diagram of key measuring points in one embodiment;

[0049] Figure 7 It is a structural block diagram of a device for optimizing the insulation level of a UHV flexible DC transmission system in one embodiment;

[0050] Figure 8 FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application 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 application and are not used to limit the present application.

[0052] The present application embodiment provides a method for optimizing the insulation level of a UHV flexible DC transmission system. The present application embodiment can be executed by a computer device, such as Figure 1 As shown, the computer device can obtain the topology, equipment parameters and control protection strategy of the ultra-high voltage flexible direct current transmission system, and then optimize the insulation level of the ultra-high voltage flexible direct current transmission system. It can be understood that the computer device can be implemented through a server, or through a terminal, or through an interactive system between a terminal and a server. In this embodiment, the method includes Figure 2 The steps shown are:

[0053] Step S201, obtaining an overvoltage simulation program for key equipment under various operation modes according to the topology, equipment parameters and control protection strategy of the ultra-high voltage flexible direct current transmission system.

[0054] The UHV flexible DC transmission system may be a typical UHV flexible DC transmission system with hybrid bridges at both ends.

[0055] The topology may adopt a symmetrical bipolar wiring form, the equipment parameters may be set according to the actual project, and the control and protection strategy may include a converter-level control module and a converter valve control module.

[0056] According to the PSCAD / EMTDC electromagnetic transient simulation program (EMTDC is the electromagnetic transient simulation software computing core, the full name is Electromagnetic Transients including DC; PSCAD provides a graphical operation interface for EMTDC), as well as the topology, equipment parameters and control protection strategy of the UHV flexible DC transmission system, the electromagnetic transient simulation model of the UHV flexible DC transmission system can be obtained. The electromagnetic transient simulation model includes the modeling of key equipment of the UHV flexible DC transmission system such as topology, AC system equivalent, converter transformer, DC reactor, converter, and control protection strategy such as converter level control module and converter valve control module. According to the electromagnetic transient simulation model of the UHV flexible DC transmission system, the overvoltage simulation program of key equipment of the UHV flexible DC transmission system under various operating modes can be obtained.

[0057] Among them, the AC system can use the equivalent Thevenin voltage source model and perform equivalent modeling based on the actual engineering operation mode and short-circuit capacity. The converter transformer can be equivalently modeled using the classic modeling method of electromagnetic transient DC analysis (EMTDC). The DC reactor can be equivalently modeled using inductance.

[0058] The converter-level control module can adopt a direct current control method. The outer loop rectifier side controls the DC side voltage (active physical quantity) and the AC side voltage (reactive physical quantity), and the inverter side controls the active power (active physical quantity) and the AC side voltage (reactive physical quantity). The control part of the converter-level control module can be divided into three modules: the inner loop current control module, the outer loop current control module and the sending end outer loop control module. Specifically, the inner loop current control module collects the three-phase AC current, obtains the d-axis and q-axis components through coordinate transformation, and then designs the dq decoupling module according to the differential mode voltage expression so that the d and q axes are independently designed with PI controller control; the control targets of the outer loop current control module are divided into two categories, active control targets and reactive control targets. The active type is independently controlled with the inner loop current d-axis component command, and the reactive type control target is independently controlled with the inner loop current q-axis component command; the sending end outer loop control adopts fixed DC voltage and fixed AC voltage, and the receiving end outer loop control adopts fixed active power and fixed AC voltage control.

[0059] Since the number of MMC (Modular Multilevel Converter) sub-modules in the UHV flexible DC transmission system is large, the nearest level approximation method and sub-module capacitor voltage sorting method can be used for the converter valve control. The modulation module calculates the number of sub-modules that need to be turned on in the MMC bridge arm at any time by rounding the ratio of the bridge arm modulation wave to the average value of all sub-module capacitances (UCAV) in the bridge arm. At the same time, the sub-module capacitor voltage sorting method is used to ensure voltage balance, and the complete sorting method is adopted.

[0060] Exemplarily, the number of MMC submodules can be set to 200, the number of simulation model levels is 201 levels, the voltage reference modulation wave is output by the outer loop, the nearest level approximation strategy is adopted, and the complete sorting method is used to ensure the balance of the submodule capacitor voltage. In addition, the power supply impedance of the ground voltage source of the ultra-high voltage flexible direct current transmission system is calculated according to the three-phase short-circuit current and short-circuit ratio of the system, using the non-ideal source RR / / L, the equivalent impedance amplitude is 4.8113Ω, and the phase angle is 86.3086°. The converter transformer connection group is YNyn0, the transformer capacity is 750MVA, and the ratio of the high-voltage winding to the low-voltage winding line voltage is 525kV / 208kV. The DC reactor uses an inductance of 75mH for equalization.

[0061] Step S202, according to the overvoltage simulation program, simulation analysis of key measuring points of the converter station under various fault conditions is performed to obtain overvoltage data, submodule locking time and lightning arrester configuration scheme of key measuring points of the converter station under various fault conditions.

[0062] Fault conditions may include single-phase grounding fault conditions on the AC bus and converter transformer side, two-phase grounding fault conditions, three-phase grounding fault conditions and two-phase phase-to-phase short circuit fault conditions, converter valve short circuit fault conditions, valve top grounding fault conditions, DC bus grounding fault conditions, DC pole line grounding fault conditions, DC pole-to-pole short circuit fault conditions, and DC pole line break fault conditions.

[0063] According to the overvoltage simulation program, the arrester scheme E can be selected for configuration first. After the UHV flexible DC transmission system simulation enters the steady state, different fault conditions can be set to perform simulation analysis of key measurement points of the converter station under various fault conditions, including simulation analysis of end-to-ground overvoltage and end-to-end overvoltage of key equipment and electrical nodes. For example, a fault can be set after 5s, and for permanent faults, a submodule locking signal is triggered 2ms after the fault occurs.

[0064] The overvoltage data of the key measuring points of the converter station under various fault conditions can be recorded, as well as the fault conditions, arrester configuration schemes and submodule blocking time corresponding to each overvoltage data. Taking the busbar single-phase grounding fault on the sending-end converter transformer valve side as an example, the overvoltage data records of the corresponding key measuring points are shown in Table 1.

[0065] Table 1 Overvoltage data records of key measuring points

[0066] ① ② ③ ④ ⑤ ⑥ ⑦ ⑧ 270 478 556 556 635 / 850 89

[0067] In simulation analysis, the submodule blocking signal can be extended or shortened, and the submodule blocking signal can be set to be triggered 2.5ms or 1.5ms after the fault occurs. Then reacquire the overvoltage data and record the corresponding fault conditions, arrester configuration scheme and submodule blocking time.

[0068] In the simulation analysis, the arrester configuration scheme can also be changed, and then the overvoltage data can be re-obtained, and the corresponding fault conditions, arrester configuration scheme and submodule blocking time can be recorded. Among them, overvoltage can also be called internal overvoltage.

[0069] Step S203, obtaining an entity relationship diagram according to the overvoltage data of key measuring points of the converter station under various fault conditions, the submodule blocking time and the arrester configuration scheme.

[0070] According to the simulation analysis of the key measuring points of the converter station under various fault conditions, the internal overvoltage waveform and overvoltage amplitude at the key equipment of the converter station under various fault conditions are obtained as overvoltage data, and simulation condition settings such as submodule locking time and lightning arrester configuration scheme are obtained.

[0071] The overvoltage data of the key measuring points are taken as the simulation results obtained by simulating the key measuring points; the submodule locking time and the lightning arrester configuration scheme of the key measuring points are taken as the simulation settings of the key measuring points; the key measuring points, the simulation results obtained by simulating the key measuring points and the simulation settings of the key measuring points are taken as entities, and key attributes and descriptive attributes are given to each entity. Specifically, the attributes of the key measuring point entity include simulation ID (Identification), converter transformer grid side, converter transformer valve side, valve bottom to ground, valve top to ground, DC line to ground, neutral bus, both ends of the valve and both ends of the DC reactor; the attributes of the simulation result entity include voltage amplitude and voltage waveform, among which the attributes of the voltage amplitude include ID, simulation ID and internal overvoltage value; the attributes of the voltage waveform include ID, simulation ID, time, voltage value and step size attributes; the attributes of the simulation setting entity include ID, simulation ID, lightning arrester layout scheme and submodule locking time.

[0072] The key measuring points are taken as the main table, the simulation results obtained by simulating the key measuring points and the simulation settings of the key measuring points are taken as sub-tables, and the table associations between the key measuring point main table and the simulation result sub-table and the simulation setting sub-table are established. Symbols are used to represent entities, attributes and the relationship between entities, and the following is obtained: Figure 3 and Figure 4 The entity relationship diagram shown.

[0073] Step S204: obtaining an overvoltage simulation database according to the entity relationship diagram.

[0074] According to the entity relationship diagram, the relationship model of the key measuring point main table is obtained; the data types of the key measuring point main table, the simulation result subtable and the simulation setting subtable are obtained; according to the relationship model of the key measuring point main table and the data types of each table, the overvoltage simulation database is obtained.

[0075] Specifically, the visualization software can be used to connect to the database software. According to the relationship mode of the key measurement point main table and the data types of the key measurement point main table, simulation result subtable and simulation setting subtable, the number, structure, association, and type and length of related fields of the key measurement point main table, simulation result subtable and simulation setting subtable can be set, and the corresponding attributes can be added to ensure that the design of the key measurement point main table, simulation result subtable and simulation setting subtable meets the storage requirements of the experimental data. Click the Save or Apply button to complete the creation of the new table. The overvoltage data, submodule locking time and lightning arrester configuration scheme of the key measurement points of the converter station under various fault conditions obtained by simulation are imported into the visualization software by selecting the target table, thereby completing the establishment of the overvoltage simulation database of the UHV flexible DC system.

[0076] Among them, the requirements for establishing an overvoltage simulation database for UHV flexible DC systems include: ① Data storage requirements: The database should support the import of multiple data formats, including unstructured data such as voltage waveforms and lightning arrester configuration schemes. ② Storage structure design: The storage structure of the database should adopt a hierarchical design, with each key measurement point as the top layer, and the simulation results and simulation operating condition records of specific measurement points at the lower layer, and establish an association and indexing mechanism. ③ Data analysis interface: The database supports interfaces with data analysis tools such as Python and MATALB, which facilitates users to conduct in-depth data analysis and model building, so as to further carry out research on overvoltage characteristics.

[0077] Step S205, obtaining a strong association rule between the overvoltage state change and the submodule locking time and the arrester configuration scheme according to the overvoltage simulation database, so as to optimize the insulation level of the UHV flexible DC transmission system according to the strong association rule.

[0078] The overvoltage state, submodule lockout time and arrester configuration scheme in the overvoltage simulation database are processed and a correlation analysis database is constructed; each record of the correlation analysis database contains a state mark of the overvoltage state, adjustment information of the submodule lockout time and adjustment information of the arrester configuration scheme.

[0079] According to the set minimum support, the association analysis database is scanned multiple times, and the overvoltage state change information, submodule lockout time adjustment information and lightning arrester configuration scheme that exceed the set minimum support are taken as frequent item sets; the confidence between several frequent item sets is calculated; and the frequent item sets with support higher than the set minimum support and confidence higher than the set minimum confidence are screened out to form strong association rules between overvoltage state changes and submodule lockout time and lightning arrester configuration schemes.

[0080] In the above-mentioned method for optimizing the insulation level of the ultra-high voltage flexible direct current transmission system, when determining the insulation scheme of the ultra-high voltage flexible direct current transmission system, the overvoltage data of the key measuring points of the converter station under various fault conditions of the ultra-high voltage flexible direct current transmission system, the submodule locking time and the arrester configuration scheme data are referred to obtain an overvoltage simulation database; according to the overvoltage simulation database, a strong association rule between the overvoltage state change and the submodule locking time and the arrester configuration scheme is obtained, and according to the strong association rule, the insulation level of the ultra-high voltage flexible direct current transmission system is optimized. Specifically, according to the strong association rule and its support and confidence, corresponding adjustments can be made for the overvoltage exceeding limit situation inside the ultra-high voltage flexible direct current transmission system, thereby reducing the overvoltage data of the ultra-high voltage flexible direct current transmission system, providing effective decision support for the insulation level of the ultra-high voltage flexible direct current transmission system, and thus improving the optimization degree of the insulation level of the ultra-high voltage flexible direct current transmission system.

[0081] In one of the embodiments, an entity relationship diagram is obtained based on overvoltage data, submodule locking time and lightning arrester configuration scheme of key measuring points of the converter station under various fault conditions, and the specific steps are as follows: the overvoltage data of the key measuring points are used as the simulation results obtained by simulating the key measuring points; the submodule locking time and lightning arrester configuration scheme of the key measuring points are used as simulation settings of the key measuring points; the key measuring points, the simulation results obtained by simulating the key measuring points and the simulation settings of the key measuring points are used as entities, and key attributes and descriptive attributes are assigned to each entity; the key measuring points are used as the main table, the simulation results obtained by simulating the key measuring points and the simulation settings of the key measuring points are used as sub-tables, and inter-table associations are established between the key measuring point main table and the simulation result sub-table and the simulation setting sub-table to obtain an entity relationship diagram.

[0082] The overvoltage data of the key measuring points are taken as the simulation results obtained by simulating the key measuring points; the submodule locking time and the lightning arrester configuration scheme of the key measuring points are taken as the simulation settings of the key measuring points; the key measuring points, the simulation results obtained by simulating the key measuring points and the simulation settings of the key measuring points are taken as entities, and key attributes and descriptive attributes are given to each entity. Specifically, the attributes of the key measuring point entity include simulation ID, converter transformer grid side, converter transformer valve side, valve bottom to ground, valve top to ground, DC line to ground, neutral bus, both ends of the valve and both ends of the DC reactor; the attributes of the simulation result entity include voltage amplitude and voltage waveform, among which the attributes of the voltage amplitude include ID, simulation ID and internal overvoltage value; the attributes of the voltage waveform include ID, simulation ID, time, voltage value and step size attributes; the attributes of the simulation setting entity include ID, simulation ID, lightning arrester layout scheme and submodule locking time.

[0083] The key measuring points are taken as the main table, the simulation results obtained by simulating the key measuring points and the simulation settings of the key measuring points are taken as sub-tables, and the table associations between the key measuring point main table and the simulation result sub-table and the simulation setting sub-table are established. Symbols are used to represent entities, attributes and the relationship between entities, and the following is obtained: Figure 3 and Figure 4 The entity relationship diagram shown in the figure shows the connections and attributes between key measurement points, simulation results and simulation settings.

[0084] Among them, the inter-table association relationship between the key measuring point main table and the simulation result sub-table and the simulation setting sub-table is as follows: the primary key of the key measuring point main table is the measuring point ID, the primary key of the simulation result sub-table is the simulation ID, and the primary key of the simulation setting sub-table is the simulation ID. Since there is a "many-to-many" relationship between the key measuring points and the simulation results and simulation settings, the association between the key measuring point main table and the simulation result sub-table and the simulation setting sub-table is established through the intermediate table. As the "many" party on both sides, the intermediate table must contain the foreign keys on both sides, and the two foreign keys point to the primary keys of the two tables respectively. Taking association table 1 as an example, association table 1 contains two attributes, simulation ID and measuring point ID, which are the foreign keys of the simulation result sub-table and the key measuring point main table, pointing to the primary keys of the two tables respectively.

[0085] In this embodiment, the key measuring points, the simulation results obtained by simulating the key measuring points, and the simulation settings of the key measuring points are taken as entities, and key attributes and descriptive attributes are given to each entity; the key measuring points are taken as the main table, the simulation results obtained by simulating the key measuring points, and the simulation settings of the key measuring points are taken as sub-tables, and an inter-table association is established between the key measuring point main table and the simulation result sub-table and the simulation setting sub-table, thereby obtaining an entity relationship diagram.

[0086] In one of the embodiments, an overvoltage simulation database is obtained according to an entity relationship diagram, and the specific steps are as follows: according to the entity relationship diagram, a relationship model of a key measuring point main table is obtained; the data types of the key measuring point main table, the simulation result sub-table and the simulation setting sub-table are obtained; according to the relationship model of the key measuring point main table and the data types of each table, an overvoltage simulation database is obtained.

[0087] According to the entity relationship diagram, the relationship mode of the main table of key measuring points is obtained. The relationship mode of the main table of key measuring points is as follows: key measuring points (simulation ID, converter transformer grid side, converter transformer valve side, valve bottom to ground, valve top to ground, DC line to ground, neutral bus, both ends of the valve, both ends of the DC reactor); voltage amplitude (ID, simulation ID, internal overvoltage amplitude); voltage waveform (ID, simulation ID, time, voltage value, step size); simulation settings (ID, simulation ID, submodule locking time, lightning arrester configuration plan).

[0088] The data in the key measurement point main table, simulation result sub-table and simulation setting sub-table include structured data and unstructured data.

[0089] The structured data types of the key measuring point main table, simulation result sub-table and simulation setting sub-table are as follows: the simulation ID adopts a numeric integer type, which is the unique identifier of each simulation record and is automatically incremented; the internal overvoltage value and sub-module locking time adopt a double-precision floating point type for high-precision storage; the specific key measuring points (such as the converter transformer grid side, converter transformer valve side, etc.) adopt the text type, increase the measuring point digital identification field, and adopt a numeric integer type to simplify the query and ensure the complete record of the measuring point name.

[0090] The unstructured data types of the key measurement point main table, simulation result sub-table, and simulation setting sub-table are as follows:

[0091] Arrester configuration schemes use variable character varchar type, which can use letters and numbers to flexibly represent arrester configurations and their change schemes. There are two arrester configuration schemes involved in the simulation, E and F schemes, where E1 represents a scheme after fine-tuning E scheme, and E2 represents another scheme after fine-tuning E scheme after overvoltage simulation, and F1 and F2 are analogous. The specific arrester configuration schemes are as follows: Figure 5 As shown in the figure. The overvoltage waveform data uses a time series format, and the voltage value at each time point is stored in the form of a timestamp. The time field of the overvoltage waveform data uses the datetime type, and the voltage value uses the double type. The time and voltage value of each row together represent the specific simulation time and corresponding voltage value of a sampling point.

[0092] You can use the visualization software to connect to the database software. According to the relationship mode of the key measurement point main table and the data types of the key measurement point main table, simulation result subtable and simulation setting subtable, set the number, structure, association, and type and length of related fields of the key measurement point main table, simulation result subtable and simulation setting subtable, add corresponding attributes, ensure that the design of the key measurement point main table, simulation result subtable and simulation setting subtable meets the storage requirements of the experimental data, and click the Save or Apply button to complete the creation of the new table. The overvoltage data, submodule locking time and lightning arrester configuration scheme of the key measurement points of the converter station under various fault conditions obtained by simulation are imported into the visualization software by selecting the target table, thereby completing the establishment of the overvoltage simulation database of the UHV flexible DC system.

[0093] In this embodiment, an overvoltage simulation database of the UHV flexible DC system is obtained according to the relational model of the main table of key measuring points and the data types of each table.

[0094] In one of the embodiments, based on the overvoltage simulation database, a strong association rule between the overvoltage state change and the sub-module lockout time and the lightning arrester configuration scheme is obtained, and the specific steps are as follows: the overvoltage simulation database is processed and an association analysis database is constructed; each record of the association analysis database contains a state mark of the overvoltage state, adjustment information of the sub-module lockout time and adjustment information of the lightning arrester configuration scheme; according to the set minimum support, the association analysis database is scanned multiple times to obtain a number of frequent item sets; the frequent item sets include overvoltage state change information, sub-module lockout time adjustment information and lightning arrester configuration scheme that exceed the set minimum support; the confidence between the several frequent item sets is calculated; according to the set minimum confidence, a strong association rule between the overvoltage state change and the sub-module lockout time and the lightning arrester configuration scheme is obtained.

[0095] The data processing of the overvoltage simulation database is as follows: according to the category of the overvoltage state in the overvoltage simulation database, the state mark of the overvoltage state is determined; according to the adjustment direction of the blocking time of the submodule in the overvoltage simulation database, the adjustment mark of the submodule blocking time is determined; according to the scheme category to which the lightning arrester configuration scheme in the overvoltage simulation database belongs, the adjustment information of the lightning arrester configuration scheme is obtained. The state mark of the overvoltage state, the adjustment information of the submodule blocking time, and the adjustment information of the lightning arrester configuration scheme with an associated relationship are taken as a record to obtain an associated analysis database.

[0096] The minimum support can be set according to the actual situation. According to the set minimum support, the association analysis database can be scanned multiple times using data mining technology, and the association rule mining algorithm such as the Apriori algorithm can be used to scan the association analysis database multiple times, and the overvoltage state change information, submodule lockout time adjustment information and arrester configuration scheme records that exceed the set minimum support are taken as frequent item sets to obtain several frequent item sets; the calculation formula of the support is shown in formula (1).

[0097] (1)

[0098] A and B are two attribute subsets (A, B∈I) in the database Y, which can be an overvoltage state change information set, a submodule lockout time adjustment information set, or a lightning arrester configuration scheme set. The representation of the association rule is A→B, s(A→B) represents the support between A and B, where the number of occurrences of A and B are recorded as σ(A) and σ(B), respectively.

[0099] For example, if “overvoltage state”=1 appears 6 times and “submodule blocking time”=up appears 4 times, the confidence level is 70%.

[0100] The confidence between several frequent item sets can be calculated according to formula (2), where the confidence represents the confidence that the overvoltage state inside the UHV flexible DC transmission system will change when a certain submodule or arrester configuration scheme is adjusted.

[0101] (2)

[0102] Among them, c(A→B) represents the confidence between A and B.

[0103] The minimum confidence can be set according to the actual situation, for example, the minimum confidence can be set to 60%. Based on the set minimum support and the set minimum confidence, the frequent item sets with support higher than the set minimum support and confidence higher than the set minimum confidence are screened out to form a strong association rule between the overvoltage state change and the submodule locking time and the arrester configuration scheme.

[0104] After obtaining the strong association rules, the relationship between the overvoltage state and the lockout time and the arrester configuration can be identified according to the strong association rules. For example, it may be found that when "overvoltage state = 1", the lockout time is adjusted to "up" more frequently. Based on the analysis results, targeted adjustment strategies can be formulated for the UHV flexible DC transmission system to reduce the overvoltage risk, such as modifying the arrester configuration under a specific configuration to ensure the safe and stable operation of the UHV flexible DC transmission system.

[0105] In this embodiment, data processing is performed on the overvoltage simulation database, and an association analysis database is constructed; based on the set minimum support and the set minimum confidence, a strong association rule between the overvoltage state change and the submodule locking time and the arrester configuration scheme is obtained.

[0106] In one of the embodiments, the overvoltage data includes an overvoltage amplitude and an overvoltage waveform, and the overvoltage simulation database is processed to obtain an associated analysis database. The specific steps are as follows: the overvoltage amplitude limit is obtained according to the median of the overvoltage amplitude of each key measuring point; the overvoltage state in the overvoltage simulation database is divided into three categories according to the overvoltage amplitude limit, so as to determine the state mark of the overvoltage state according to the category of the overvoltage state in the overvoltage simulation database; when the lockout time of the submodule in the overvoltage simulation database is adjusted upward, the adjustment information of the lockout time of the submodule is determined to be the first adjustment mark; when the lockout time of the submodule in the overvoltage simulation database is adjusted downward, the adjustment information of the lockout time of the submodule is determined to be the second adjustment mark; according to the scheme category to which the lightning arrester configuration scheme in the overvoltage simulation database belongs, the adjustment information of the lightning arrester configuration scheme is obtained; the state mark of the overvoltage state with an associated relationship, the adjustment information of the submodule lockout time, and the adjustment information of the lightning arrester configuration scheme are taken as a record to obtain an associated analysis database.

[0107] The overvoltage amplitude limit is obtained based on the median of the overvoltage amplitude at each key measuring point, and the range of ±5% is regarded as the normal range.

[0108] According to the overvoltage amplitude limit, the overvoltage state in the overvoltage simulation database is divided into three categories, so as to determine the state mark of the overvoltage state according to the category of the overvoltage state in the overvoltage simulation database; specifically, the normal overvoltage state is marked as 0, the overvoltage over the upper limit state is marked as 1, and the overvoltage over the lower limit state is marked as -1. For example, if the overvoltage at the measuring points at both ends of the valve is 850V, and the set overvoltage amplitude upper limit is 800V, the overvoltage state mark of the measuring points at both ends of the valve is 1.

[0109] When the blocking time of the submodule in the overvoltage simulation database is adjusted upward, the adjustment information of the blocking time of the submodule is determined to be the first adjustment mark "up"; when the blocking time of the submodule in the overvoltage simulation database is adjusted downward, the adjustment information of the blocking time of the submodule is determined to be the second adjustment mark "down". For example, if the blocking time of the submodule is adjusted from 2ms to 2.5ms, the adjustment information mark of the blocking time of the submodule is "up".

[0110] According to the scheme category of the arrester configuration scheme in the overvoltage simulation database, the adjustment information of the arrester configuration scheme is obtained. Among them, the arrester configuration scheme is divided into two types: E and F. The adjustment of the E scheme is represented by E1, E2 and E3, and the adjustment of the F scheme is represented by F1, F2 and F3. Figure 5 shown.

[0111] The state mark of the overvoltage state with an associated relationship, the adjustment information of the submodule blocking time and the adjustment information of the arrester configuration scheme are taken as a record to obtain the associated analysis database shown in Table 2.

[0112] surface Example structure of association analysis database

[0113] Overvoltage condition Lock time Arrester configuration 1 up E1 -1 down F2

[0114] In this embodiment, the state mark of the overvoltage state is determined according to the category of the overvoltage state in the overvoltage simulation database; the adjustment mark of the sub-module locking time is determined according to the adjustment direction of the sub-module locking time in the overvoltage simulation database; the adjustment information of the lightning arrester configuration scheme is obtained according to the scheme category to which the lightning arrester configuration scheme in the overvoltage simulation database belongs; the state mark of the overvoltage state, the adjustment information of the sub-module locking time and the adjustment information of the lightning arrester configuration scheme that have an associated relationship are taken as a record to obtain an associated analysis database.

[0115] In one of the embodiments, the key measuring points include at least one of a converter transformer grid side measuring point, a converter transformer valve side measuring point, a valve bottom to ground measuring point, a valve top to ground measuring point, a DC line to ground measuring point, a neutral busbar measuring point, a valve end measuring point, and a DC reactor end voltage measuring point.

[0116] like Figure 6 As shown, the key measuring points include at least one of ① measuring point on the converter transformer grid side, ② measuring point on the converter transformer valve side, ③ measuring point on the valve bottom to the ground, ④ measuring point on the valve top to the ground, ⑤ measuring point on the DC line to the ground, ⑥ measuring point on the neutral busbar, ⑦ measuring points at both ends of the valve and ⑧ measuring points on both ends of the DC reactor.

[0117] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0118] Based on the same inventive concept, the embodiment of the present application also provides an insulation level optimization device for a UHV flexible DC transmission system for realizing the insulation level optimization method of the UHV flexible DC transmission system involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in the embodiments of the insulation level optimization device for one or more UHV flexible DC transmission systems provided below can refer to the limitations of the insulation level optimization method for the UHV flexible DC transmission system above, and will not be repeated here.

[0119] In an exemplary embodiment, Figure 7 As shown, a device for optimizing the insulation level of a UHV flexible DC transmission system is provided, wherein:

[0120] The simulation program acquisition module 701 is used to obtain the overvoltage simulation program of key equipment under each typical operation mode according to the topology, equipment parameters and control protection strategy of the ultra-high voltage flexible direct current transmission system;

[0121] A simulation analysis module 702 is used to perform simulation analysis of key measuring points of the converter station under various fault conditions according to the overvoltage simulation program, and obtain overvoltage data, submodule locking time and lightning arrester configuration scheme of key measuring points of the converter station under various fault conditions;

[0122] An entity relationship diagram acquisition module 703 is used to obtain an entity relationship diagram according to the overvoltage data of key measuring points of the converter station under each fault condition, the submodule locking time and the arrester configuration scheme;

[0123] A simulation database acquisition module 704 is used to obtain an overvoltage simulation database according to the entity relationship diagram;

[0124] The strong association rule acquisition module 705 is used to: obtain the strong association rules between the overvoltage state change and the submodule locking time and the lightning arrester configuration scheme according to the overvoltage simulation database, so as to optimize the insulation level of the ultra-high voltage flexible direct current transmission system according to the strong association rules.

[0125] In one of the embodiments, the entity relationship diagram acquisition module 703 is also used to: use the overvoltage data of the key measuring point as the simulation result obtained by simulating the key measuring point; use the sub-module locking time and the lightning arrester configuration scheme of the key measuring point as the simulation setting of the key measuring point; use the key measuring point, the simulation result obtained by simulating the key measuring point, and the simulation setting of the key measuring point as entities, and assign key attributes and descriptive attributes to each entity; use the key measuring point as the main table, the simulation result obtained by simulating the key measuring point, and the simulation setting of the key measuring point as sub-tables, and establish inter-table associations between the key measuring point main table and the simulation result sub-table and the simulation setting sub-table to obtain an entity relationship diagram.

[0126] In one of the embodiments, the simulation database acquisition module 704 is also used to: obtain the relationship model of the key measuring point main table according to the entity relationship diagram; obtain the data types of the key measuring point main table, the simulation result sub-table and the simulation setting sub-table; and obtain the overvoltage simulation database according to the relationship model of the key measuring point main table and the data types of each table.

[0127] In one of the embodiments, the strong association rule acquisition module 705 is also used to: perform data processing on the overvoltage simulation database and construct an association analysis database; each record of the association analysis database contains a state mark of the overvoltage state, adjustment information of the submodule lockout time and adjustment information of the lightning arrester configuration scheme; according to the set minimum support, the association analysis database is scanned multiple times to obtain a number of frequent item sets; the frequent item sets include overvoltage state change information exceeding the set minimum support, submodule lockout time adjustment information and lightning arrester configuration scheme; calculate the confidence between several frequent item sets; according to the set minimum confidence, obtain the strong association rules between the overvoltage state change and the submodule lockout time and the lightning arrester configuration scheme.

[0128] In one of the embodiments, the strong association rule acquisition module 705 is also used to: obtain the overvoltage amplitude limit according to the median of the overvoltage amplitude of each key measuring point; divide the overvoltage state in the overvoltage simulation database into three categories according to the overvoltage amplitude limit, so as to determine the state mark of the overvoltage state according to the category of the overvoltage state in the overvoltage simulation database; when the lockout time of the submodule in the overvoltage simulation database is adjusted upward, determine the adjustment information of the lockout time of the submodule as the first adjustment mark; when the lockout time of the submodule in the overvoltage simulation database is adjusted downward, determine the adjustment information of the lockout time of the submodule as the second adjustment mark; obtain the adjustment information of the lightning arrester configuration scheme according to the scheme category to which the lightning arrester configuration scheme in the overvoltage simulation database belongs; and use the state mark of the overvoltage state, the adjustment information of the submodule lockout time, and the adjustment information of the lightning arrester configuration scheme that have an associated relationship as a record to obtain an associated analysis database.

[0129] In one of the embodiments, the key measuring points include at least one of a converter transformer grid side measuring point, a converter transformer valve side measuring point, a valve bottom to ground measuring point, a valve top to ground measuring point, a DC line to ground measuring point, a neutral busbar measuring point, a valve end measuring point, and a DC reactor end voltage measuring point.

[0130] Each module in the above-mentioned device for optimizing the insulation level of the ultra-high voltage flexible direct current transmission system can be implemented in whole or in part by software, hardware, or a combination thereof. Each of the above-mentioned modules can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to each of the above modules.

[0131] In an exemplary embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as shown in FIG. Figure 8As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. Among them, the processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store data of an embodiment of a method for optimizing the insulation level of an ultra-high voltage flexible direct current transmission system. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a method for optimizing the insulation level of an ultra-high voltage flexible direct current transmission system is implemented.

[0132] Those skilled in the art will understand that Figure 8 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0133] In one embodiment, a computer device is further provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps in the above method embodiments when executing the computer program.

[0134] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0135] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0136] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0137] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment method can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, an artificial intelligence (AI) processor, etc., but are not limited to this.

[0138] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0139] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for optimizing the insulation level of a UHV flexible direct current transmission system, characterized in that: The method comprises: According to the topology, equipment parameters and control protection strategy of the UHV flexible DC transmission system, the overvoltage simulation program of key equipment under each operation mode is obtained; According to the overvoltage simulation program, simulation analysis of key measuring points of the converter station under various fault conditions is performed to obtain overvoltage data, submodule locking time and arrester configuration scheme of key measuring points of the converter station under various fault conditions; According to the overvoltage data of the key measuring points of the converter station under each fault condition, the submodule locking time and the arrester configuration scheme, an entity relationship diagram is obtained; According to the entity relationship diagram, an overvoltage simulation database is obtained; According to the overvoltage simulation database, a strong association rule between the overvoltage state change and the submodule locking time and the lightning arrester configuration scheme is obtained, so as to optimize the insulation level of the ultra-high voltage flexible direct current transmission system according to the strong association rule.

2. The method according to claim 1, characterized in that According to the overvoltage data of the key measuring points of the converter station under each fault condition, the submodule locking time and the arrester configuration scheme, an entity relationship diagram is obtained, including: The overvoltage data of the key measuring points are used as the simulation results obtained by simulating the key measuring points; The submodule blocking time and arrester configuration scheme of key measuring points are used as simulation settings of key measuring points; Taking key measuring points, simulation results obtained by simulating the key measuring points, and simulation settings of the key measuring points as entities, and assigning key attributes and descriptive attributes to each entity; The key measuring points are taken as the main table, the simulation results obtained by simulating the key measuring points and the simulation settings of the key measuring points are taken as sub-tables, and inter-table associations are established between the key measuring point main table and the simulation result sub-table and the simulation setting sub-table to obtain an entity relationship diagram.

3. The method according to claim 2, characterized in that The overvoltage simulation database is obtained according to the entity relationship diagram, including: According to the entity relationship diagram, the relationship model of the key measurement point main table is obtained; Get the data types of the key measurement point main table, simulation result sub-table and simulation setting sub-table; An overvoltage simulation database is obtained according to the relational model of the key measuring point main table and the data types of each table.

4. The method according to claim 1, characterized in that: The method of obtaining a strong correlation rule between the overvoltage state change and the submodule locking time and the arrester configuration scheme according to the overvoltage simulation database includes: Performing data processing on the overvoltage simulation database and constructing a correlation analysis database; each record of the correlation analysis database includes a state mark of the overvoltage state, adjustment information of the submodule locking time and adjustment information of the arrester configuration scheme; According to the set minimum support, the association analysis database is scanned multiple times to obtain a number of frequent item sets; the frequent item sets include overvoltage state change information exceeding the set minimum support, submodule locking time adjustment information and arrester configuration scheme; Calculate the confidence between several frequent item sets; According to the set minimum confidence, the strong correlation rules between the overvoltage state change and the submodule blocking time and the arrester configuration scheme are obtained.

5. The method according to claim 4, characterized in that The overvoltage data includes an overvoltage amplitude and an overvoltage waveform, and the overvoltage simulation database is processed to obtain a correlation analysis database, including: According to the median of the overvoltage amplitude at each key measuring point, the overvoltage amplitude limit is obtained; According to the overvoltage amplitude limit, the overvoltage states in the overvoltage simulation database are divided into three categories, so as to determine the state mark of the overvoltage state according to the category of the overvoltage state in the overvoltage simulation database; When the lockout time of the submodule in the overvoltage simulation database is adjusted upward, determining the adjustment information of the lockout time of the submodule as a first adjustment mark; When the lockout time of the submodule in the overvoltage simulation database is adjusted downward, determining the adjustment information of the lockout time of the submodule to be a second adjustment mark; According to the scheme category to which the lightning arrester configuration scheme in the overvoltage simulation database belongs, adjustment information of the lightning arrester configuration scheme is obtained; The state mark of the overvoltage state having an associated relationship, the adjustment information of the submodule blocking time and the adjustment information of the arrester configuration scheme are taken as a record to obtain an associated analysis database.

6. The method according to claim 1, characterized in that The key measuring points include at least one of the measuring points on the converter transformer grid side, the measuring points on the converter transformer valve side, the measuring points on the valve bottom to the ground, the measuring points on the valve top to the ground, the measuring points on the DC line to the ground, the neutral busbar measuring points, the measuring points at both ends of the valve and the voltage measuring points at both ends of the DC reactor.

7. An insulation level optimization device for a UHV flexible DC transmission system, characterized in that: The device comprises: The simulation program acquisition module is used to obtain the overvoltage simulation program of key equipment under various typical operation modes according to the topology, equipment parameters and control protection strategy of the UHV flexible DC transmission system; A simulation analysis module, used to perform simulation analysis of key measuring points of the converter station under various fault conditions according to the overvoltage simulation program, and obtain overvoltage data, submodule locking time and arrester configuration scheme of key measuring points of the converter station under various fault conditions; An entity relationship diagram acquisition module is used to obtain an entity relationship diagram according to the overvoltage data of key measuring points of the converter station under each fault condition, the submodule locking time and the arrester configuration scheme; A simulation database acquisition module, used to obtain an overvoltage simulation database according to the entity relationship diagram; The strong association rule acquisition module is used to: obtain the strong association rules between the overvoltage state change and the submodule locking time and the lightning arrester configuration scheme according to the overvoltage simulation database, so as to optimize the insulation level of the ultra-high voltage flexible direct current transmission system according to the strong association rules.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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