Grid-connected detection method and device of AC / DC power distribution system, medium and product

Abstract

The invention discloses a grid-connected detection method, device, medium and product for an AC / DC power distribution system, and the method comprises the steps: building a power flow model of the AC / DC power distribution system before grid connection of a distributed power supply, obtaining a time sequence power flow result according to the power flow model, carrying out the reliability calculation of the AC / DC power distribution system, and obtaining a reliability calculation index, and according to the time sequence power flow result and the reliability calculation index, constructing a comprehensive performance index of the AC / DC power distribution system, and according to the comprehensive performance index, generating operation state information of the AC / DC power distribution system for distributed power supply grid connection. According to the operation state information, weak links needing to be transformed of the AC / DC power distribution system can be determined, technical support and guidance can be provided for a distributed power supply grid connection strategy, and safe and reliable operation of the AC / DC power distribution system can be promoted. By optimizing scheduling and power supply planning, the operation efficiency of the AC / DC power distribution system can be improved, the operation cost can be reduced, and the accuracy of grid-connected detection of the AC / DC power distribution system can be improved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of power grid detection, and in particular to a grid connection detection method, equipment, medium and product for an AC / DC power distribution system. Background Art

[0002] With the innovative development of technologies such as distributed power grid connection, traditional AC distribution networks are gradually being replaced by AC / DC distribution systems containing a large number of distributed power sources. AC / DC distribution systems have obvious advantages in terms of power supply quality, energy loss, safety and stability. AC / DC distribution systems are usually composed of distributed power sources such as AC power grids, DC power grids, converter stations, photovoltaics and wind turbines. Converters and distributed power sources contain complex control strategies and operating modes, which increases the difficulty of steady-state and transient analysis. At the same time, the connection of distributed power sources and DC power grids may change the flow direction and distribution of power flows, increasing the complexity of risk assessment and reliability calculation of AC / DC distribution systems. Therefore, it is necessary to conduct a comprehensive evaluation of the safety, stability, power quality, reliability and economy of AC / DC distribution systems, and provide guidance and suggestions for distributed power grid connection strategies and construction plans.

[0003] Since AC / DC distribution systems contain a large number of power electronic devices, control and protection equipment, and controllable loads, modeling, simulation, analysis, and optimized operation and control of AC / DC distribution systems are more challenging. At present, the traditional grid-connected detection method of AC / DC distribution systems containing distributed power sources obtains real-time data such as voltage and current of distributed power sources after grid connection through measurement data, and then establishes an evaluation index system and model to qualitatively evaluate the current power quality of AC / DC distribution systems. However, this method cannot provide guidance on the location and strategy of distributed power sources before grid connection, and mainly focuses on the impact of distributed power sources on AC distribution networks, ignoring the impact of voltage source converter stations and DC power grids, resulting in low accuracy of grid-connected detection of AC / DC distribution systems. Summary of the invention

[0004] The present invention provides a method, device, medium and product for detecting grid connection of an AC / DC power distribution system, so as to improve the accuracy of the detection grid connection of the AC / DC power distribution system.

[0005] In a first aspect, an embodiment of the present invention provides a method for detecting grid connection of an AC / DC power distribution system, the method comprising:

[0006] Establishing a power flow model of an AC / DC power distribution system before the distributed power generation is connected to the grid, and obtaining a time series power flow result according to the power flow model;

[0007] Performing reliability calculation on the AC / DC power distribution system to obtain reliability calculation indicators;

[0008] Constructing a comprehensive performance index of the AC / DC power distribution system according to the time sequence power flow result and the reliability calculation index;

[0009] The operating status information of the AC / DC power distribution system for connecting the distributed power source to the grid is generated according to the comprehensive performance index.

[0010] In a second aspect, an embodiment of the present invention further provides a grid connection detection device for an AC / DC power distribution system, the device comprising:

[0011] A time-series power flow result acquisition module is used to establish a power flow model of the AC / DC power distribution system before the distributed power source is connected to the grid, and obtain time-series power flow results according to the power flow model;

[0012] A reliability calculation index acquisition module, used to perform reliability calculation on the AC / DC power distribution system to obtain reliability calculation indexes;

[0013] A comprehensive performance index calculation module, used to construct a comprehensive performance index of the AC / DC power distribution system according to the time sequence power flow result and the reliability calculation index;

[0014] A motion state information generating module is used to generate the motion state information of the AC / DC power distribution system for connecting the distributed power source to the grid according to the comprehensive performance index.

[0015] In a third aspect, an embodiment of the present invention further provides a computer device, the computer device comprising:

[0016] one or more processors;

[0017] A storage device for storing one or more programs;

[0018] When the one or more programs are executed by the one or more processors, the one or more processors implement the grid-connection detection method for the AC / DC power distribution system provided in the first aspect of the present invention.

[0019] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the grid-connection detection method for an AC / DC power distribution system as provided in the first aspect of the present invention.

[0020] In a fifth aspect, an embodiment of the present invention further provides a computer program product, the computer program product comprising a computer program, and when the computer program is executed by a processor, the grid-connection detection method for an AC / DC power distribution system provided in the first aspect of the present invention is implemented.

[0021] In this embodiment, a power flow model of the AC / DC power distribution system before the distributed power source is connected to the grid is established, and the time series power flow results are obtained according to the power flow model, and the reliability calculation index is calculated for the AC / DC power distribution system, and the comprehensive performance index of the AC / DC power distribution system is constructed according to the time series power flow results and the reliability calculation index, and the operation status information of the AC / DC power distribution system for the distributed power source grid connection is generated according to the comprehensive performance index. According to the operation status information, the weak links that need to be transformed in the AC / DC power distribution system can be identified, and at the same time, technical support and guidance can be provided for the distributed power source grid connection strategy, which is conducive to promoting the safe and reliable operation of the AC / DC power distribution system. By optimizing scheduling and power supply planning, the operating efficiency of the AC / DC power distribution system can be improved, the operating cost can be reduced, and the accuracy of the grid connection detection of the AC / DC power distribution system can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a flow chart of a grid connection detection method for an AC / DC power distribution system provided according to Embodiment 1 of the present invention;

[0023] Figure 2 is a schematic diagram of a DC distribution network topology structure provided according to Embodiment 1 of the present invention;

[0024] Figure 3 is a schematic diagram of a topological structure of an AC / DC power distribution system provided according to Embodiment 1 of the present invention;

[0025] Figure 4 This is a structural example diagram of a grid-connected detection device for an AC / DC power distribution system provided according to a second embodiment of the present invention;

[0026] Figure 5 It is a structural diagram of a computer device provided according to Embodiment 3 of the present invention. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme 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 described embodiments 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 should fall within the scope of protection of the present invention.

[0028] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present invention described herein can cover sequential implementations other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0029] Embodiment 1

[0030] See also Figure 1 , shows a flow chart of a method for detecting a grid connection of an AC / DC power distribution system provided by a first embodiment of the present invention. The method can be executed by a grid connection detection device for an AC / DC power distribution system. The grid connection detection device for an AC / DC power distribution system can be implemented in the form of hardware and / or software. The grid connection detection device for an AC / DC power distribution system can be configured in a computer device. Figure 1 As shown, the method includes:

[0031] Step 101: Establish a power flow model of an AC / DC power distribution system before a distributed power source is connected to the grid, and obtain a sequential power flow result according to the power flow model.

[0032] The AC / DC power distribution system is a system used for power transmission and distribution, combining two current forms: alternating current and direct current. In the AC / DC power distribution system, AC is used for long-distance power transmission and large-scale power distribution because of its low energy loss during transmission; while DC is often used for precision control of power equipment, electronic equipment, and some special applications such as motor drive, battery charging, and data transmission. The AC / DC power distribution system can flexibly switch and adjust the current type according to demand to ensure that energy is efficiently and stably supplied to various types of power-consuming equipment.

[0033] Distributed generation grid connection refers to connecting distributed generation to the power grid so that it can work with the power grid to supply or absorb electricity. Distributed generation grid connection requires solving the problems of power synchronization, scheduling and protection.

[0034] The time series power flow results mainly refer to the time series changes of electrical parameters such as power, voltage, load, etc. of the AC / DC power distribution system at different time points within a certain time range.

[0035] In this embodiment, the AC / DC power distribution system is analyzed in time sequence by the power flow model, so as to evaluate the time sequence changes of the power, voltage, load and other electrical parameters of the AC / DC power distribution system at different time points, and the scheduling and stability analysis of the AC / DC power distribution system are assisted by the time sequence power flow results. This analysis is usually important for stabilizing the AC / DC power distribution system, optimizing power distribution, and dealing with the uncertainty and volatility caused by distributed power sources.

[0036] Exemplarily, the power flow model includes an AC power grid model, a DC network model, a voltage source converter model, and a distributed power source model.

[0037] In one embodiment of the present invention, step 101 may include the following steps:

[0038] Step 1011: Establish an AC power grid model according to the control strategy of the voltage source converter.

[0039] A voltage source converter (VSC) is a power electronic device that can convert direct current into alternating current. Its main function is to accurately control the flow of electrical energy and the transmission of power by adjusting the amplitude, frequency and phase of the output voltage.

[0040] In this embodiment, a mathematical model simulating the behavior of an AC power grid (i.e., an AC power grid model) is constructed by a control method of a voltage source converter. The control strategy generally involves adjusting the output voltage, frequency, and phase of the voltage source converter, thereby achieving stability of parameters such as voltage and frequency of the AC / DC power distribution system.

[0041] For example, the voltage source converter can operate under different control strategies, and different control strategies have a direct impact on the AC power grid model established by the voltage source converter on the AC side and the expression of the power flow equation. For example, when the voltage source converter operates under constant power control, the AC power grid model that can be established by the voltage source converter on the AC side is a constant power source, and its power flow equation can be expressed as:

[0042]

[0043] Where P i represents the active power injected by node i, Q i represents the reactive power injected by node i, n represents the number of nodes, V i Represents the voltage amplitude of node i, V j represents the voltage amplitude of node j, G ij represents the real element of the node admittance matrix, B ij represents the imaginary element of the node admittance matrix, θ ij represents the voltage phase angle between node i and node j, Ps Indicates the active power injected into the DC side, Q s Represents the reactive power injected into the DC side.

[0044] When the voltage source converter operates in voltage control mode, the AC side can be equivalent to a PV node, and active power flow engineering needs to be established. For AC and DC distribution systems containing multiple voltage source converters, a master-slave control strategy can be used to coordinate the work of each voltage source converter to establish an AC power grid model.

[0045] Step 1012: Establish a DC network model according to electrical parameters of the DC network.

[0046] DC networks transmit electrical energy through direct current. Unlike AC grids, DC grids are typically used in application scenarios such as long-distance power transmission, efficient power conversion, and integration of renewable energy.

[0047] In this embodiment, a DC network model that reflects the behavior and operating characteristics of the DC grid is constructed by using electrical parameters in the DC grid (such as voltage, current, resistance, conductivity, etc.). Establishing a DC network model can accurately describe and analyze the dynamic behavior of the DC network and evaluate the performance of the DC network under different operating conditions, such as voltage fluctuations, current changes, power transmission, etc.

[0048] For example, the power flow equation for the DC network model can be calculated by the following formula:

[0049]

[0050] In the formula, I dci represents the injected current of node i, R ik Represents DC resistance, V dci represents the injected voltage at node i, V dcj represents the injected voltage at node j.

[0051] For example, for a single-stage symmetrically grounded AC / DC power distribution system, the injected current I at node i is dci It can also be calculated by the following power flow equation:

[0052]

[0053] In the formula, I dci represents the injected current of node i, P dci represents the injected active power of node i, V dci represents the injected voltage at node i.

[0054] Step 1013: Establish a voltage source converter model according to the electrical parameters of the voltage source converter.

[0055] In this embodiment, by analyzing the electrical parameters of the voltage source converter (VSC) (such as the electrical parameters of the transformer, filter, commutation impedance and rectifier), a voltage source converter model is established to describe the behavior of the voltage source converter in the AC / DC power distribution system.

[0056] Exemplarily, the voltage source converter model is calculated by the following power flow equation:

[0057] S s =V s I tf ;

[0058] V f =V s +I tf ·Z tf ;

[0059] Q f =-B f ·|V f | 2 ;

[0060] S cf =V c I cf ;

[0061] P loss =a+b·|I c |+c·|I c | 2 ;

[0062] P c =-P dci -P loss ;

[0063] In the formula, S s represents the complex power injected into the AC bus S, V s Indicates the voltage of the AC bus S, I tf Represents the current on the converter transformer, V f represents the voltage of the AC bus f, Z tf Represents the equivalent impedance of the AC transformer, Q f Indicates the reactive power of the AC bus f, B f Represents the admittance of the AC filter, I cf represents the current on the commutation impedance, S cf Represents the apparent power flowing through the commutation impedance, V c Represents the voltage of the commutation impedance, I cf Indicates the current flowing through the commutation impedance, P loss represents the loss of the voltage source converter, and a, b and c represent the loss coefficients.

[0064] Step 1014: predict the distributed power output curve according to the meteorological condition data, and establish a distributed power model according to the distributed power output curve.

[0065] In this embodiment, by analyzing meteorological condition data (such as wind speed, light intensity, etc.), the output curve (i.e., power generation output curve) of distributed power sources (such as distributed power sources such as wind turbines and photovoltaics) is predicted, and based on these predicted output curves, a distributed power source model is established to describe the operating characteristics of the distributed power source model in the AC / DC power distribution system, which can effectively simulate the power generation fluctuations and changes of the distributed power sources.

[0066] For example, the output characteristics of distributed power sources such as wind turbines and photovoltaics are affected by meteorological conditions such as wind speed and light intensity. The output curve of distributed power sources can be predicted in real time through meteorological condition data. When the distributed power source is connected to the grid through the AC side, the grid connection point can be equivalent to a PQ node or a PV node. For example, if the grid connection point is equivalent to a PQ node, the power flow equation on the AC side of the distributed power model can be modified to:

[0067]

[0068] Where P i represents the active power injected by node i, Q i represents the reactive power injected by node i, n represents the number of nodes, V i Represents the voltage amplitude of node i, V j represents the voltage amplitude of node j, G ij represents the real element of the node admittance matrix, B ij represents the imaginary element of the node admittance matrix, θ ij represents the voltage phase angle between node i and node j, P s Indicates the active power injected into the DC side, Q s Represents the reactive power injected into the DC side, P DG，t represents the injected active power of distributed generation t, Q DG，t Represents the injected reactive power of distributed generation t.

[0069] For example, when the distributed power source is connected to the grid via the DC side, the power generation unit does not generate reactive power, and the power flow equation on the DC side of the distributed power source model can be modified as follows:

[0070]

[0071] Where P dci represents the injected active power of node i, P DG,t represents the injected active power of distributed generation t, V dci represents the injected voltage at node i, R ik Represents DC resistance, Vdcj represents the injected voltage at node j.

[0072] The corresponding time flow results can be obtained according to the AC grid model, DC grid model, voltage source converter model and distributed power supply model.

[0073] Step 102: Perform reliability calculation on the AC / DC power distribution system to obtain reliability calculation indicators.

[0074] In this embodiment, the reliability of the AC / DC power distribution system is calculated by using the reliability network equivalence technology to evaluate the stability and fault resistance of the AC / DC power distribution system under different working conditions. The reliability indicators (such as the average annual power outage time of the load and the average power outage time of the distributed power source) can be calculated by simplifying the structural model of the AC / DC power distribution system, which helps to identify potential risks and weak links.

[0075] In one embodiment of the present invention, step 102 may include the following steps:

[0076] Step 1021: Obtain a fault mode and influencing cause matrix based on the topological structure and shortest power supply path analysis of the AC and DC power distribution systems.

[0077] In this embodiment, if Figure 2 The figure shows the topological structure of the DC distribution network. In the topological structure of the DC distribution network, 1-7 are DC bus, DG is the distributed power source, q 2 ,q 4 ,q 5 ,q 7 All represent the failure probability of the disconnector, and LD1-LD7 are DC loads. Through the analysis of the AC / DC power distribution system topology and the shortest power supply path, the failure mode and impact cause matrix FMECM describing the impact of branch faults in the AC / DC distribution network on the upstream and downstream loads can be calculated.

[0078] Exemplarily, calculating the failure mode and cause matrix FMECM includes: using a topology search algorithm to traverse the entire AC / DC distribution network, determine the upstream and downstream branches of each load point, identify and mark important nodes and branches, which may have a greater impact on the stability of the AC / DC distribution system and the power supply of the load when a fault occurs. The topology search algorithm includes but is not limited to algorithms such as depth-first search and breadth-first search.

[0079] Furthermore, for each load point in the AC / DC distribution network, the shortest path algorithm is used to calculate the shortest power supply path from the power source point to the load point, and the information of these paths is recorded and stored, including the branches, buses and corresponding impedance or distance parameters on the path. The shortest path algorithm includes but is not limited to the shortest path algorithm, Floyd algorithm and greedy algorithm based on spatial direction.

[0080] Finally, for each branch fault of the AC / DC distribution network, the power flow calculation or fault analysis method is used to evaluate the impact of the fault on the upstream and downstream loads. According to the evaluation results, the corresponding elements of the fault mode and impact cause matrix FMECM are calculated and filled as follows:

[0081]

[0082] Where FMECM represents the failure mode and cause matrix, q i represents the failure probability of the i-th protection device in the AC / DC power distribution system.

[0083] Step 1022: Obtain a load type matrix based on the failure mode and impact cause matrix, and convert the load type matrix into a failure maintenance impact time matrix.

[0084] In this embodiment, by analyzing the failure mode and the influencing cause matrix, the response and impact of different types of loads under the fault condition are obtained, thereby forming a load type matrix. Then, this load type matrix is ​​converted into a fault maintenance impact time matrix, which is used to quantify the recovery time required for each type of load after the fault occurs. The recovery time of different load types when a fault occurs in the AC / DC power distribution system is evaluated and predicted, thereby helping to optimize the fault response strategy of the AC / DC power distribution system and improve the reliability and recovery efficiency of the AC / DC power distribution system.

[0085] Exemplarily, the load failure rate index is calculated according to the failure mode and influencing cause matrix FMECM, and the calculation formula is as follows:

[0086]

[0087] In the formula, λ load-n represents the failure rate of load n, λ branch-n represents the failure rate of branch n, and FMECM represents the failure mode and influence cause matrix.

[0088] The failure probability of protection equipment in AC and DC power distribution systems is set to 0, and the failure mode and influencing cause matrix FMECM is recalculated to obtain the load type matrix LTM.

[0089] Modify the branch switching time in the load type matrix LTM to 0 and the corresponding branch maintenance time to 1 to obtain the fault maintenance impact time matrix FMECM i .

[0090] Step 1023: Calculate the annual average power outage time of the load based on the failure mode and impact cause matrix and the failure maintenance impact time matrix.

[0091] In this embodiment, by analyzing the fault mode and influencing cause matrix and the fault maintenance impact time matrix of the AC / DC power distribution system, the average annual power outage time of the load is calculated, and the impact of the AC / DC power distribution system on various loads under different fault conditions is quantified, especially the duration of the load power outage. Through this calculation, the reliability of the AC / DC power distribution system can be evaluated and possible weak links can be identified.

[0092] For example, the average annual power outage time of the load can be calculated by the following formula:

[0093]

[0094] Where U load-n represents the average annual power outage time of the load, λ branch-n Indicates the annual average time of the branch, FMECM i It stands for Failure Maintenance Impact Time Matrix and FMECM stands for Failure Mode and Impact Cause Matrix.

[0095] Step 1024: island the load of the AC / DC power distribution system to obtain an island range, and construct a load path recovery matrix for the distributed power source within the island range.

[0096] In this embodiment, in the AC / DC power distribution system, by isolating the loads, it is determined which areas will become islands and be divided into island ranges (i.e., areas that cannot be connected to the AC / DC power distribution system) when a fault occurs. Then, a recovery path matrix of the distributed power supply for the loads within these island ranges is constructed, and how the distributed power supply provides power restoration services for the loads within the island range is analyzed, thereby improving the resilience and fault recovery capability of the AC / DC power distribution system.

[0097] Exemplarily, the following optimization equation may be used for island division:

[0098]

[0099] In the formula, S k is the load importance factor, M is the load set within the island, S DG is the maximum power supply capacity, Lk is the power consumed by load k, f L To optimize the goal.

[0100] On the basis of obtaining the island range, it is necessary to supplement the influence of distributed power generation in the reliability calculation, and a recovery matrix L representing the load path of distributed power generation within the island range can be constructed. DG(m,n) , the expressions of each element are as follows:

[0101]

[0102] In the formula, D represents the island range, m represents the fault branch, n represents the corresponding node load, and L DG(m,n) . represents the load path recovery matrix.

[0103] Step 1025: Obtain a distributed power generation fault maintenance impact time matrix according to the load type matrix and the load path restoration matrix.

[0104] In this embodiment, by combining the load type matrix and the load path recovery matrix, the distributed power supply fault maintenance impact time matrix of the distributed power supply on the load recovery when the distributed power supply fails is calculated. The load type matrix describes the characteristics of different types of loads, and the load path recovery matrix reflects the time required for the distributed power supply to restore power to the loads in different island ranges. Through this step, it is possible to evaluate the time required for various loads to recover when a distributed power supply failure occurs and its impact on the overall reliability of the AC / DC power distribution system.

[0105] For example, the distributed generation load type matrix LTM can be calculated by the load type matrix and the load path restoration matrix: DG , the calculation formula is as follows:

[0106] LTM DG =LTM+L DG ;

[0107] Where, LTM DG Indicates that the distributed power generation complies with the type matrix, L DG represents the load path restoration matrix and LTM represents the load type matrix.

[0108] Distributed generation load type matrix LTM DG The branch switch time in is changed to 0, the corresponding branch switch time plus the distributed power supply startup time is changed to 1, and the corresponding branch repair time is changed to 2, and the distributed power supply fault maintenance impact time matrix FMITM is obtained. DG .

[0109] Step 1026: Calculate the average power outage time of the distributed power source based on the distributed power source fault maintenance impact time matrix and the fault mode and impact cause matrix.

[0110] In this embodiment, the average power outage time of distributed power sources is calculated, and the impact of distributed power sources on load recovery in the event of an AC or DC power distribution system failure or power outage is evaluated by combining the distributed power source fault maintenance impact time matrix with the failure mode and impact cause matrix.

[0111] Exemplarily, the calculation formula for the average power outage time of distributed power sources is as follows:

[0112]

[0113] Where, FMECM DG is the maintenance impact time matrix of distributed power generation failure, U load-n represents the average annual power outage time of the load, λ branch-n represents the annual average time of the branch, and FMECM represents the failure mode and effect cause matrix.

[0114] Step 103: construct comprehensive performance indicators of the AC / DC power distribution system according to the time sequence power flow results and the reliability calculation indicators.

[0115] In this embodiment, the time series flow results are combined with the reliability calculation index to comprehensively evaluate the overall performance of the AC / DC power distribution system. The time series flow results reflect the power flow state of the AC / DC power distribution system at different time points, while the reliability calculation index reflects the reliability performance of the AC / DC power distribution system in the face of faults. By combining the time series flow results and the reliability calculation index, a comprehensive performance index can be obtained to help evaluate the comprehensive performance of the AC / DC power distribution system under normal operation and fault conditions.

[0116] In one embodiment of the present invention, the comprehensive performance index includes a power quality index, and the power quality index includes at least a voltage deviation rate and a line loss rate.

[0117] The calculation formula of voltage deviation rate is:

[0118]

[0119] The calculation formula of line loss rate is:

[0120]

[0121] Among them, V node represents the voltage deviation rate, N represents the number of nodes, T represents the statistical time, V k Represents the operating voltage of the AC / DC power distribution system at each moment, V k，R Indicates rated voltage, S line represents the line loss rate, L represents the number of branches, P k Represents the line loss of AC and DC power distribution systems, S N Indicates the rated capacity of the AC and DC power distribution system.

[0122] In one embodiment of the present invention, the comprehensive performance index also includes a reliability index, and the reliability index at least includes an average power outage duration and an average power outage rate of users.

[0123] The calculation formula for the average power outage duration of users is:

[0124]

[0125] The calculation formula for the average power outage rate is:

[0126]

[0127] Among them, I CAIDI Indicates the average power outage duration of users, L D Indicates the number of loads, U i Indicates the average annual power outage time of the load, N i represents the number of users, λ i represents the load failure rate, I ASAI Indicates the average power outage rate.

[0128] In one embodiment of the present invention, the comprehensive performance index also includes a system vulnerability index, and the system vulnerability index at least includes a system node vulnerability index and a system branch vulnerability index.

[0129] Among them, the calculation formula of the system node vulnerability index is:

[0130]

[0131] The calculation formula of the system branch vulnerability index is:

[0132]

[0133] Among them, NB k represents the node vulnerability index, k represents the node number, l k represents the load loss when node k fails, l N Represents the total load of the AC and DC power distribution system, S 1 Indicates the power supply set, L 2 represents the load set, R ij (k) represents the judgment function of whether node k is on the power supply path, Z represents the total power supply path, NB s represents the system node vulnerability index, N represents the number of nodes, LB T represents the branch vulnerability index, T represents the branch number, l T represents the load loss when branch T fails, R ij (T) represents the judgment function of whether branch T is on the power supply path, LBs represents the system branch vulnerability index, and L represents the number of branches.

[0134] Step 104: Generate operation status information of the AC / DC power distribution system for grid-connecting distributed power sources according to the comprehensive performance index.

[0135] In this embodiment, the comprehensive performance index is integrated into the time series flow result and the reliability calculation index, and the fuzzy comprehensive evaluation method is used according to the comprehensive performance index to generate the operation status information of the AC / DC power distribution system for distributed power grid connection, and the stability, reliability and efficiency of the AC / DC power distribution system in the grid connection process are evaluated to ensure that the AC / DC power distribution system can be smoothly connected to the grid and operate stably under different load and power conditions. The fuzzy comprehensive evaluation method can handle the complex relationship and uncertainty between different indicators, and integrate the influence of various performance indicators through weighted average and other methods, and finally obtain a comprehensive evaluation result (i.e., the operation status information of the AC / DC power distribution system for distributed power grid connection). The operation status information refers to the real-time operation parameters and performance of the AC / DC power distribution system when it is connected to the grid, such as electrical data such as voltage, current, and power, which are used to monitor and optimize the operation status of the AC / DC power distribution system.

[0136] In one embodiment of the present invention, step 104 may include the following steps:

[0137] Step 1041: Calculate the weight matrix of the comprehensive performance index using the hierarchical analysis method.

[0138] In this embodiment, the analytic hierarchy process is a commonly used method for determining the weights of comprehensive performance indicators, and is particularly suitable for comprehensive performance indicators with multiple levels. First, it is necessary to clarify the comprehensive performance indicators, which are the various performance indicators in the target layer, performance layer, and indicator layer. Then, the importance of each performance indicator at the same level with respect to a certain evaluation indicator at the previous level is compared pairwise to construct a judgment matrix. Finally, the judgment matrix is ​​checked for consistency and the weight is calculated to obtain the weight matrix A.

[0139] Step 1042: construct an evaluation set, and calculate the fuzzy judgment matrix of the comprehensive performance index using the triangular membership function based on the evaluation set.

[0140] The evaluation set is a language description of the performance of the comprehensive performance indicators. The evaluation set is as follows:

[0141] v=(V 1 , V 2 , V 3 , V 4 );

[0142] In the formula, v represents the evaluation set, v 1 Indicates excellent, v 2 Indicates good, v 3 Indicates general, v 4 Indicates poor.

[0143] The triangular membership function is used to describe the degree of membership of an element to a fuzzy set. The degree of membership of each indicator in the comprehensive performance index relative to the evaluation set v is calculated to form the fuzzy judgment matrix R. The expression of the triangular membership function is as follows:

[0144]

[0145] Where R(x) represents the triangular membership function, and a, b, and c represent the parameters of the triangular membership function.

[0146] The parameters a, b, and c determine the shape and location of the triangular membership functions.

[0147] In this embodiment, the evaluation set is constructed based on the different evaluation values ​​covered by the comprehensive performance index to form an evaluation set. These evaluation values ​​are fuzzified by using a triangular membership function to obtain a fuzzy judgment matrix of the comprehensive performance index. The qualitative or uncertain evaluation values ​​are converted into fuzzy values, thereby solving the deviation or uncertainty that may occur in the traditional evaluation method, making the evaluation process more flexible and accurate.

[0148] Step 1043: Calculate the evaluation matrix of the comprehensive performance index according to the weight matrix and the fuzzy judgment matrix to obtain the fuzzy evaluation result.

[0149] In this embodiment, the weight matrix of the comprehensive performance index obtained by the hierarchical analysis method is combined with the fuzzy judgment matrix obtained by the triangular membership function to obtain an evaluation matrix of the comprehensive performance index. This evaluation matrix reflects the influence of the comprehensive performance index in the overall evaluation of the AC / DC power distribution system, and the final fuzzy evaluation result is obtained by the fuzzy comprehensive evaluation method. The relative importance and uncertainty of different performance indicators are quantified to obtain a comprehensive and objective evaluation result, thereby accurately evaluating the comprehensive performance of the AC / DC power distribution system.

[0150] Exemplarily, the evaluation matrix B is calculated by the weight matrix A and the fuzzy judgment matrix R, and the calculation formula is as follows:

[0151] B = A·R;

[0152] In the formula, B represents the evaluation matrix, A represents the weight matrix, and R represents the fuzzy judgment matrix.

[0153] Step 1044: convert the fuzzy evaluation result into operation status information of the AC / DC power distribution system for connecting the distributed power source to the grid.

[0154] In this embodiment, the fuzzy evaluation results are converted into motion state information, and a comprehensive evaluation of the distributed power grid connection of the AC and DC power distribution system is performed to facilitate comparison and ranking of different distributed power grid connection strategies and select the most reasonable distributed power grid connection strategy.

[0155] Exemplarily, in order to verify the feasibility of the grid-connected detection method for the AC / DC power distribution system provided in an embodiment of the present invention, the test system IEEE RBTS 6-Feeder F4 for power system reliability analysis is used as a test example. The test system is powered by a voltage source converter as a DC distribution network, forming a complex AC / DC power distribution system. Figure 3 is a schematic diagram of the topology of the AC / DC power distribution system provided by an embodiment of the present invention, such as Figure 3 As shown, in the AC / DC power distribution system, LP1-LP13 and LP18-LP22 are AC loads, LP14-LP17 are DC loads, L1-L10 and L15-L29 are AC transmission lines, L11-L14 are DC transmission lines, and VSC is a voltage source converter.

[0156] In order to analyze the impact of different distributed generation grid-connection modes and grid-connection locations on the AC / DC distribution system, four different grid-connection strategies are set up, as shown in Table 1.

[0157] Table 1. Schematic diagram of different distributed generation grid connection strategies

[0158]

[0159]

[0160] The various indicators before and after the grid connection of different distributed generation grid connection strategies are calculated respectively, and the calculation results are shown in Table 2 below.

[0161] Table 2. Calculation results of AC and DC distribution system indicators before and after grid connection for different distributed generation grid connection strategies.

[0162]

[0163] It can be seen from Table 2 that the voltage deviation rate of strategy A is 0.0312, which is 38.22% lower than 0.0505 before grid connection; the line loss rate of strategy B is 0.0138, which is 7.38% lower than 0.0149 before grid connection; the average power outage duration of users of strategy A is 5.485, which is 18.11% lower than 6.698 before grid connection; the average power outage rate of strategy A is 0.99865, which is 0.03% higher than 0.9983 before grid connection; the system node vulnerability index and system branch vulnerability index of strategy A are 0.0916 and 0.0814 respectively, which are 43.36% and 43.47% lower than 0.162 and 0.144 before grid connection. Therefore, the reasonable distributed generation grid connection strategy significantly improves the power supply quality and safety reliability of AC and DC distribution systems.

[0164] In order to evaluate the comprehensive impact of different distributed generation grid-connected strategies on AC and DC distribution systems, the fuzzy comprehensive evaluation method is used to measure and evaluate the performance indicators of each strategy. The evaluation performance indicator weights are calculated using the Delphi method, and the calculation results are shown in Table 3.

[0165] Table 3. Schematic diagram of evaluation index weights

[0166]

[0167]

[0168] The comprehensive evaluation results and the specific scores of each comment are shown in Table 4.

[0169] Table 4. Schematic diagram of comprehensive evaluation results and specific scores for each comment

[0170] Strategy <![CDATA[Excellent v 1 > <![CDATA[Good v 2 > <![CDATA[General v 3 > <![CDATA[Poor v 4 > Fraction Before grid connection 0.1386 0.2148 0.2336 0.2747 7.1107 A 0.1970 0.4033 0.2736 0.1221 8.6419 B 0.1517 0.3036 0.1824 0.2620 7.5414 C 0.1935 0.2793 0.3804 0.1430 8.4925 D 0.1944 0.2615 0.3917 0.1487 8.4720

[0171] It can be seen from Table 4 that the distributed generation grid connection strategy significantly improves the comprehensive performance of the AC and DC distribution system. Specifically, strategy A has the highest comprehensive score, indicating that it performs best in various evaluation indicators. Therefore, when selecting a distributed generation grid connection strategy, strategy A should be given priority.

[0172] In an embodiment of the present invention, a power flow model of an AC / DC power distribution system before a distributed power source is connected to the grid is established, and a time-series power flow result is obtained according to the power flow model, and a reliability calculation is performed on the AC / DC power distribution system to obtain a reliability calculation index, and a comprehensive performance index of the AC / DC power distribution system is constructed according to the time-series power flow result and the reliability calculation index, and the operation status information of the AC / DC power distribution system for connecting the distributed power source to the grid is generated according to the comprehensive performance index. According to the operation status information, the weak links that need to be transformed in the AC / DC power distribution system can be identified, and at the same time, technical support and guidance can be provided for the distributed power source grid connection strategy, which is conducive to promoting the safe and reliable operation of the AC / DC power distribution system. By optimizing scheduling and power supply planning, the operation efficiency of the AC / DC power distribution system can be improved, the operation cost can be reduced, and the accuracy of the grid connection detection of the AC / DC power distribution system can be improved.

[0173] Embodiment 2

[0174] Figure 4 A schematic diagram of a grid-connected detection device for an AC / DC power distribution system according to a second embodiment of the present invention is shown in FIG. Figure 4 As shown, the device comprises:

[0175] The time sequence power flow result acquisition module 401 is used to establish a power flow model of the AC / DC power distribution system before the distributed power source is connected to the grid, and obtain the time sequence power flow result according to the power flow model;

[0176] A reliability calculation index acquisition module 402 is used to perform reliability calculation on the AC / DC power distribution system to obtain a reliability calculation index;

[0177] A comprehensive performance index calculation module 403, used to construct a comprehensive performance index of the AC / DC power distribution system according to the time sequence power flow result and the reliability calculation index;

[0178] The motion state information generating module 404 is used to generate the motion state information of the AC / DC power distribution system for connecting the distributed power source to the grid according to the comprehensive performance index.

[0179] In one embodiment of the present invention, the power flow model includes an AC power grid model, a DC network model, a voltage source converter model and a distributed power supply model; the sequential power flow result acquisition module 401 includes:

[0180] An AC power grid model building module, used to build an AC power grid model according to a control strategy of a voltage source converter;

[0181] A DC network model building module, used for building a DC network model according to electrical parameters of the DC network;

[0182] A voltage source converter model building module, used to establish a voltage source converter model according to electrical parameters of the voltage source converter;

[0183] The distributed power model building module is used to predict the distributed power output curve according to the meteorological condition data, and to establish the distributed power model according to the distributed power output curve.

[0184] In one embodiment of the present invention, the reliability calculation index includes the average annual power outage time of the load and the average power outage time of the distributed power source; the reliability calculation index acquisition module 402 includes:

[0185] A failure mode and influencing cause matrix acquisition module is used to obtain a failure mode and influencing cause matrix according to the topological structure and shortest power supply path analysis of the AC and DC power distribution system;

[0186] A fault maintenance impact time matrix construction module is used to calculate a load type matrix according to the fault mode and impact cause matrix, and convert the load type matrix into a fault maintenance impact time matrix;

[0187] A load annual average power outage time calculation module is used to calculate the load annual average power outage time according to the failure mode and impact cause matrix and the failure maintenance impact time matrix;

[0188] A load path recovery matrix construction module, used to island the load of the AC / DC power distribution system to obtain an island range, and construct a load path recovery matrix of the distributed power source within the island range;

[0189] A fault maintenance impact time matrix building module is used to obtain a distributed power supply fault maintenance impact time matrix according to the load type matrix and the load path restoration matrix;

[0190] The distributed power supply average power outage time calculation module is used to calculate the distributed power supply average power outage time according to the distributed power supply fault maintenance impact time matrix and the fault mode and impact cause matrix.

[0191] In one embodiment of the present invention, the comprehensive performance index includes a power quality index; the power quality index includes at least a voltage deviation rate and a line loss rate;

[0192] Wherein, the calculation formula of the voltage deviation rate is:

[0193]

[0194] The calculation formula of the line loss rate is:

[0195]

[0196] Among them, V node represents the voltage deviation rate, N represents the number of nodes, T represents the statistical time, V k represents the operating voltage of the AC / DC power distribution system at each moment, V k，R Indicates rated voltage, S line represents the line loss rate, L represents the number of branches, P k represents the line loss of the AC / DC power distribution system, S N Indicates the rated capacity of the AC / DC power distribution system.

[0197] In one embodiment of the present invention, the comprehensive performance index further includes a reliability index; the reliability index at least includes an average power outage duration and an average power outage rate of users;

[0198] The calculation formula for the average power outage duration of the user is:

[0199]

[0200] The calculation formula of the average power outage rate is:

[0201]

[0202] Among them, I CAIDI represents the average power outage duration of the user, LD Indicates the number of loads, U i Indicates the average annual power outage time of the load, N i represents the number of users, λ i represents the load failure rate, I ASAI represents the average power outage rate.

[0203] In one embodiment of the present invention, the comprehensive performance index further includes a system vulnerability index; the system vulnerability index at least includes a system node vulnerability index and a system branch vulnerability index;

[0204] The calculation formula of the system node vulnerability index is:

[0205]

[0206] The calculation formula of the system branch vulnerability index is:

[0207]

[0208] Among them, NB k represents the node vulnerability index, k represents the node number, l k represents the load loss when node k fails, l N represents the total load of the AC / DC power distribution system, S 1 Indicates the power supply set, L 2 represents the load set, R ij (k) represents the judgment function of whether the node k is on the power supply path, Z represents the total power supply path, NB s represents the vulnerability index of the system node, N represents the number of nodes, LB T represents the branch vulnerability index, T represents the branch number, l T represents the load loss when branch T fails, R ij (T) represents the judgment function of whether the branch T is on the power supply path, LB s represents the branch vulnerability index of the system, and L represents the number of branches.

[0209] In one embodiment of the present invention, the motion state information generating module 404 includes:

[0210] A weight matrix calculation module, used for calculating the weight matrix of the comprehensive performance index by using the hierarchical analysis method;

[0211] A fuzzy judgment matrix calculation module is used to construct an evaluation set and calculate the fuzzy judgment matrix of the comprehensive performance index using a triangular membership function according to the evaluation set;

[0212] A fuzzy evaluation result acquisition module, used to calculate the evaluation matrix of the comprehensive performance index according to the weight matrix and the fuzzy judgment matrix to obtain a fuzzy evaluation result;

[0213] An operation status information conversion module is used to convert the fuzzy evaluation result into operation status information of the AC / DC power distribution system for connecting the distributed power source to the grid.

[0214] The AC / DC power distribution system grid-connection detection device provided in the embodiment of the present invention can execute the AC / DC power distribution system grid-connection detection method provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of executing the AC / DC power distribution system grid-connection detection method.

[0215] Embodiment 3

[0216] See also Figure 5 , showing a schematic diagram of the structure of a computer device provided by an embodiment of the present invention. The computer device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workbenches, personal digital assistants, blade servers, mainframe computers, and other suitable computers. The computer device may also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0217] like Figure 5 As shown, the computer device 10 includes at least one processor 11, and a memory connected to the at least one processor 11, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., wherein the memory stores a computer program that can be executed by at least one processor, and the processor 11 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or the computer program loaded from the storage unit 18 to the random access memory (RAM) 13. Various programs and data required for the operation of the computer device 10 can also be stored in the RAM 13. The processor 11, ROM 12 and RAM 13 are connected to each other through a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0218] A number of components in the computer device 10 are connected to the I / O interface 15, including: an input unit 16, such as a keyboard, a mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a disk, an optical disk, etc.; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the computer device 10 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0219] The processor 11 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. The processor 11 executes the various methods and processes described above, such as the grid-connected detection method of the AC / DC power distribution system.

[0220] In some embodiments, the grid-connected detection method for an AC / DC power distribution system may be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as a storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on the computer device 10 via the ROM 12 and / or the communication unit 19. When the computer program is loaded into the RAM 13 and executed by the processor 11, one or more steps of the grid-connected detection method for an AC / DC power distribution system described above may be performed. Alternatively, in other embodiments, the processor 11 may be configured to execute the grid-connected detection method for an AC / DC power distribution system in any other appropriate manner (e.g., by means of firmware).

[0221] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0222] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when the computer program is executed by the processor, the functions / operations specified in the flow chart and / or block diagram are implemented. The computer program may be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0223] In the context of the present invention, a computer-readable storage medium may be a tangible medium that may contain or store a computer program for use by or in combination with an instruction execution system, device or equipment. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0224] To provide interaction with a user, the systems and techniques described herein can be implemented on a computer device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or trackball) through which the user can provide input to the computer device. Other types of devices can also be used to provide interaction with the user; for example, the feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic input, voice input, or tactile input).

[0225] The systems and techniques described herein may be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0226] A computing system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The client and server relationship is generated by computer programs running on the corresponding computers and having a client-server relationship with each other. The server may be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system to solve the defects of difficult management and weak business scalability in traditional physical hosts and VPS services.

[0227] Embodiment 4

[0228] An embodiment of the present invention further provides a computer program product, which includes a computer program. When the computer program is executed by a processor, the grid-connection detection method for an AC / DC power distribution system provided in any embodiment of the present invention is implemented.

[0229] In the process of implementation, the computer program product can be written in one or more programming languages ​​or a combination thereof to perform the computer program code of the present invention, including object-oriented programming languages, such as Java, Smalltalk, C++, and conventional procedural programming languages, such as "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computer (for example, using an Internet service provider to connect through the Internet).

[0230] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0231] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A grid connection detection method for an AC / DC power distribution system, characterized in that: The method comprises: Establishing a power flow model of an AC / DC power distribution system before the distributed power generation is connected to the grid, and obtaining a time series power flow result according to the power flow model; Performing reliability calculation on the AC / DC power distribution system to obtain reliability calculation indicators; Constructing a comprehensive performance index of the AC / DC power distribution system according to the time sequence power flow result and the reliability calculation index; The operating status information of the AC / DC power distribution system for connecting the distributed power source to the grid is generated according to the comprehensive performance index.

2. The method according to claim 1, characterized in that The power flow model includes an AC power grid model, a DC network model, a voltage source converter model and a distributed power supply model; the power flow model of the AC / DC power distribution system before the distributed power supply is connected to the grid includes: Establishing an AC power grid model based on the control strategy of the voltage source converter; Establishing a DC network model according to the electrical parameters of the DC network; Establishing a voltage source converter model according to the electrical parameters of the voltage source converter; A distributed power output curve is predicted according to meteorological condition data, and a distributed power model is established according to the distributed power output curve.

3. The method according to claim 1, characterized in that The reliability calculation index includes the average annual power outage time of the load and the average power outage time of the distributed power source; the reliability calculation of the AC / DC power distribution system to obtain the reliability calculation index includes: According to the topological structure and shortest power supply path analysis of the AC / DC power distribution system, a fault mode and influencing cause matrix is ​​obtained; A load type matrix is ​​calculated based on the failure mode and impact cause matrix, and the load type matrix is ​​converted into a failure maintenance impact time matrix; The annual average power outage time of the load is calculated based on the failure mode and impact cause matrix and the failure maintenance impact time matrix; Performing island division on the load of the AC / DC power distribution system to obtain an island range, and constructing a load path restoration matrix of the distributed power source within the island range; Obtaining a distributed power supply fault maintenance impact time matrix according to the load type matrix and the load path restoration matrix; The average power outage time of the distributed power source is calculated based on the distributed power source fault maintenance impact time matrix and the fault mode and impact cause matrix.

4. The method according to claim 1, characterized in that: The comprehensive performance index includes a power quality index; the power quality index includes at least a voltage deviation rate and a line loss rate; Wherein, the calculation formula of the voltage deviation rate is: The calculation formula of the line loss rate is: Among them, V node represents the voltage deviation rate, N represents the number of nodes, T represents the statistical time, V k represents the operating voltage of the AC / DC power distribution system at each moment, V k,R Indicates rated voltage, S line represents the line loss rate, L represents the number of branches, P k represents the line loss of the AC / DC power distribution system, S N Indicates the rated capacity of the AC / DC power distribution system.

5. The method according to claim 4, characterized in that The comprehensive performance index also includes a reliability index; the reliability index at least includes the average power outage duration and average power outage rate of users; The calculation formula for the average power outage duration of the user is: The calculation formula of the average power outage rate is: Among them, I CAIDI represents the average power outage duration of the user, L D Indicates the number of loads, U i Indicates the average annual power outage time of the load, N i represents the number of users, λ i represents the load failure rate, I ASAI represents the average power outage rate.

6. The method according to claim 5, characterized in that The comprehensive performance index also includes a system vulnerability index; the system vulnerability index at least includes a system node vulnerability index and a system branch vulnerability index; The calculation formula of the system node vulnerability index is: The calculation formula of the system branch vulnerability index is: Among them, NB k represents the node vulnerability index, k represents the node number, l k represents the load loss when node k fails, l N represents the total load of the AC / DC power distribution system, S1 represents the power source set, L2 represents the load set, R ij (k) represents the judgment function of whether the node k is on the power supply path, Z represents the total power supply path, NB s represents the vulnerability index of the system node, N represents the number of nodes, LB T represents the branch vulnerability index, T represents the branch number, l T represents the load loss when branch T fails, R ij (T) represents the judgment function of whether the branch T is on the power supply path, LB s represents the branch vulnerability index of the system, and L represents the number of branches.

7. The method according to any one of claims 1 to 6, characterized in that: The generating, according to the comprehensive performance index, the operation status information of the AC / DC power distribution system for connecting the distributed power source to the grid comprises: Calculating the weight matrix of the comprehensive performance index by using the analytic hierarchy process; Constructing an evaluation set, and calculating a fuzzy judgment matrix of the comprehensive performance index using a triangular membership function according to the evaluation set; Calculate the evaluation matrix of the comprehensive performance index according to the weight matrix and the fuzzy judgment matrix to obtain a fuzzy evaluation result; The fuzzy evaluation result is converted into operation status information of the AC / DC power distribution system for connecting the distributed power source to the grid.

8. A computer device, characterized in that: The computer device comprises: one or more processors; A storage device for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the grid-connection detection method for the AC / DC power distribution system according to any one of claims 1 to 7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the grid-connection detection method for an AC / DC power distribution system as described in any one of claims 1 to 7 is implemented.

10. A computer program product, characterized in that The computer program product comprises a computer program, and when the computer program is executed by a processor, the grid-connection detection method for an AC / DC power distribution system according to any one of claims 1 to 7 is implemented.

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