Method, device and equipment for determining interconnection and mutual aid capability of alternating current interconnection system and medium

Abstract

The application relates to the technical field of power transmission networks, and discloses a method and device for determining the interconnection and mutual aid capability of an alternating current interconnection system, equipment and a medium. First, a conventional interconnection evaluation model is constructed, and based on a conventional interconnection constraint condition set in the model, the function value of a conventional interconnection target function is optimized to obtain a conventional interconnection decision value set, which provides a decision value set under a conventional interconnection mode for optimal effect comparison. Then, a flexible interconnection evaluation model is constructed, and based on a flexible interconnection constraint condition set in the model, the function value of a flexible interconnection target function is optimized to obtain a flexible interconnection decision value set, which provides a decision value set under a flexible interconnection mode for optimal effect comparison. Finally, based on the two decision value sets, the index values of a preset index under the two modes are obtained, and then comprehensive evaluation data under the two modes are obtained, optimal effect comparison under the two modes is realized, and the interconnection and mutual aid capability of the alternating current interconnection system can be more accurately determined.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power transmission network, and particularly relates to a method and device for determining the interconnection and mutual aid capability of an alternating current interconnection system, and a medium. BACKGROUND

[0002] In the current power system, regional interconnection plays a key role in optimizing resource scheduling, balancing supply and demand differences, and enhancing system stability. However, in the related art, the accuracy of the method for determining the interconnection and mutual aid capability of an alternating current interconnection system needs to be improved. Therefore, there is an urgent need to propose a new method for determining the interconnection and mutual aid capability. SUMMARY

[0003] The present application provides a method and device for determining the interconnection and mutual aid capability of an alternating current interconnection system, and a medium, which solves the technical problem that the accuracy of the method for determining the interconnection and mutual aid capability of an alternating current interconnection system needs to be improved, and achieves the technical effect of determining the interconnection and mutual aid capability of an alternating current interconnection system more accurately.

[0004] In order to achieve the above purpose, the main technical scheme adopted by the present application includes:

[0005] In a first aspect, the present application provides a method for determining the interconnection and mutual aid capability of an alternating current interconnection system, which comprises:

[0006] constructing a conventional interconnection evaluation model; wherein the conventional interconnection evaluation model is used to represent an interconnection and mutual aid capability evaluation model of the alternating current interconnection system before the flexible interconnection device is put into operation, and the conventional interconnection evaluation model comprises a conventional interconnection objective function and a conventional interconnection constraint condition set;

[0007] optimizing the function value of the conventional interconnection objective function based on the conventional interconnection constraint condition set to obtain a conventional interconnection decision value set;

[0008] constructing a flexible interconnection evaluation model; wherein the flexible interconnection evaluation model is used to represent an interconnection and mutual aid capability evaluation model of the alternating current interconnection system after the flexible interconnection device is put into operation, and the flexible interconnection evaluation model comprises a flexible interconnection objective function and a flexible interconnection constraint condition set;

[0009] optimizing the function value of the flexible interconnection objective function based on the flexible interconnection constraint condition set to obtain a flexible interconnection decision value set;

[0010] comparing the optimal effects of the alternating current interconnection system based on the conventional interconnection decision value set and the flexible interconnection decision value set on the preset index to obtain comprehensive evaluation data before and after the flexible interconnection device is put into operation, so as to determine the interconnection and mutual aid capability of the alternating current interconnection system.

[0011] Optionally, the preset indexes include a power supply capability index, a source-load tracking coefficient index, a source-load variation coefficient index, a new energy utilization rate index, and a short-circuit current index.

[0012] Optionally, the constructing the conventional interconnection evaluation model includes:

[0013] Based on a generation cost, a wind curtailment risk cost, a light curtailment risk cost, and a load shedding risk cost of the AC interconnected system, a conventional interconnection objective function is constructed.

[0014] Based on a DC power flow equation constraint, a power flow capacity constraint, a node voltage phase angle constraint, a node power balance constraint, a generator unit output constraint, and a node wind and light curtailment constraint of the AC interconnected system, a conventional interconnection constraint condition set is constructed.

[0015] Optionally, the constructing the flexible interconnection objective function includes:

[0016] Based on a generation cost, a wind curtailment risk cost, a light curtailment risk cost, a load shedding risk cost, and a flexible interconnection device loss cost of the AC interconnected system, a flexible interconnection objective function is constructed.

[0017] Optionally, the constructing the flexible interconnection constraint condition set includes:

[0018] Based on a DC power flow equation constraint, a power flow capacity constraint, a node voltage phase angle constraint, a node power balance constraint, a generator unit output constraint, a node wind and light curtailment constraint, a flexible interconnection active power constraint, and a flexible interconnection device capacity constraint of the AC interconnected system, the flexible interconnection constraint condition set is constructed.

[0019] Optionally, the method of obtaining the conventional interconnection decision value set is consistent with the method of obtaining the flexible interconnection decision value set; and the obtaining the flexible interconnection decision value set based on the flexible interconnection constraint condition set and the optimization of the function value of the flexible interconnection objective function includes:

[0020] A differential evolution calculation is performed on the initial particle swarm to obtain a differential evolution particle swarm; wherein the differential evolution calculation includes variation, crossover, and selection.

[0021] Based on the concentration probability of each particle in the differential evolution particle swarm, a target difference particle swarm is selected.

[0022] Based on the target difference particle swarm, a global search is performed to obtain a target particle that minimizes the function value of the flexible interconnection objective function, and a flexible interconnection decision value set is determined.

[0023] Optionally, the preset indexes include a power supply capability index, a source-load tracking coefficient index, a source-load change coefficient index, a new energy utilization rate index, and a short-circuit current index, the optimal effect comparison of the AC interconnected system is performed on the preset indexes based on the conventional interconnected decision value set and the flexible interconnected decision value set, and comprehensive evaluation data before and after the flexible interconnected device is put into operation is obtained, including:

[0024] Based on the index values of the power supply capability index, the source-load tracking coefficient index, the source-load change coefficient index, the new energy utilization rate index, and the short-circuit current index before and after the flexible interconnected device is put into operation, an initial evaluation matrix is constructed; wherein the evaluation elements on the first designated row in the initial evaluation matrix are used to represent each preset index before the flexible interconnected device is put into operation; and the evaluation elements on the second designated row in the initial evaluation matrix are used to represent each preset index after the flexible interconnected device is put into operation.

[0025] The values of each evaluation element in the initial evaluation matrix are normalized to obtain a target evaluation matrix.

[0026] Based on the values of each evaluation element in the target evaluation matrix, a weighted standard value is calculated.

[0027] Based on the weighted standard value of each evaluation element, the distance of each weighted standard value to the positive ideal solution and the negative ideal solution is obtained.

[0028] Based on the distance of each weighted standard value to the positive ideal solution and the negative ideal solution, the comprehensive evaluation data before and after the flexible interconnected device is put into operation is obtained.

[0029] In a second aspect, an embodiment of the present application provides an interconnected and mutual utilization capability determination device of an AC interconnected system, the device comprising:

[0030] A conventional model construction module is configured to construct a conventional interconnected evaluation model; wherein the conventional interconnected evaluation model is used to represent an AC interconnected system interconnected and mutual utilization capability evaluation model before a flexible interconnected device is put into operation, and the conventional interconnected evaluation model includes a conventional interconnected target function and a conventional interconnected constraint condition set;

[0031] A conventional target function optimization module is configured to optimize the function value of the conventional interconnected target function based on the conventional interconnected constraint condition set, and obtain a conventional interconnected decision value set;

[0032] A flexible model construction module is configured to construct a flexible interconnected evaluation model; wherein the flexible interconnected evaluation model is used to represent an AC interconnected system interconnected and mutual utilization capability evaluation model after the flexible interconnected device is put into operation, and the flexible interconnected evaluation model includes a flexible interconnected target function and a flexible interconnected constraint condition set;

[0033] a flexible target function optimization module, configured to optimize a function value of the flexible interconnection target function based on the set of flexible interconnection constraint conditions, and obtain a set of flexible interconnection decision values;

[0034] an interconnection and mutual aid capability determination module, configured to perform optimal effect comparison on the AC interconnection system in a preset index based on the set of conventional interconnection decision values and the set of flexible interconnection decision values, and obtain comprehensive evaluation data before and after the flexible interconnection device is put into operation, so as to determine the interconnection and mutual aid capability of the AC interconnection system.

[0035] In a third aspect, an embodiment of the present application provides a computer device, comprising:

[0036] a memory and a processor, which are communicatively connected with each other, and the memory stores computer instructions, and the processor executes the computer instructions to perform the method in any of the above embodiments.

[0037] In a fourth aspect, an embodiment of the present application provides a computer readable storage medium, which stores computer instructions, and the computer instructions are used to make a computer execute the method in any of the above embodiments.

[0038] In the embodiments of the present application, first, a conventional interconnection evaluation model is constructed, and based on a set of conventional interconnection constraint conditions in the model, a function value of a conventional interconnection target function is optimized to obtain a set of conventional interconnection decision values, which provides a set of decision values in a conventional interconnection mode for optimal effect comparison; then, a flexible interconnection evaluation model is constructed, and based on a set of flexible interconnection constraint conditions in the model, a function value of a flexible interconnection target function is optimized to obtain a set of flexible interconnection decision values, which provides a set of decision values in a flexible interconnection mode for optimal effect comparison; finally, based on the sets of decision values in the conventional interconnection mode and the flexible interconnection mode, index values of a preset index in the two modes are obtained, and then comprehensive evaluation data in the two modes are obtained, optimal effect comparison in the two modes is realized, and thus the interconnection and mutual aid capability of the AC interconnection system can be more accurately determined. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed in the description of the embodiments or the prior art will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0040] Figure 1A flowchart of the method for determining the interconnection and inter-support capability of an AC interconnected system according to an embodiment of the present specification is provided.

[0041] Figure 2 A flowchart of the method for determining the interconnection and inter-support capability of an AC interconnected system according to an embodiment of the present specification is provided.

[0042] Figure 3 A flowchart of the method for determining the interconnection and inter-support capability of an AC interconnected system according to an embodiment of the present specification is provided.

[0043] Figure 4 A schematic diagram of an optimization algorithm according to an embodiment of the present specification is provided.

[0044] Figure 5 A flowchart of the method for determining the interconnection and inter-support capability of an AC interconnected system according to an embodiment of the present specification is provided.

[0045] Figure 6 A schematic diagram of a device for determining the interconnection and inter-support capability of an AC interconnected system according to an embodiment of the present specification is provided.

[0046] Figure 7 A schematic diagram of a computer structure according to an embodiment of the present specification is provided. DETAILED DESCRIPTION

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only some, but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0048] In the current power system, especially with high proportion of wind and solar energy access, the system inertia continues to decline, the frequency and voltage support capability weakens, the anti-disturbance ability decreases, and the stability after failure becomes more complex, and the overall operation risk increases significantly. At the same time, the load center power supply "hollowing", short-circuit current exceeding the standard, and source-load space-time mismatching problems are also increasingly prominent. With the strengthening of the AC network frame in the vicinity of the UHVDC, the electrical connection of the 500kV main network frame is more closely linked, the suppression of short-circuit current is more difficult, and the risk of ring opening in the local supply area also rises. Under this background, regional interconnection has become a key measure to improve power supply capacity, balance source-load fluctuations, and enhance the resilience of the power grid. However, in the related art, the accuracy of the method for determining the interconnection and inter-support capability of an AC interconnected system needs to be improved.

[0049] Based on this, the application provides a method for determining the interconnection and mutual aid capability of an AC interconnected system. First, a conventional interconnection evaluation model is constructed, wherein the conventional interconnection evaluation model is used to represent an AC interconnected system interconnection and mutual aid capability evaluation model before the flexible interconnection device is put into operation, and the conventional interconnection evaluation model comprises a conventional interconnection objective function and a conventional interconnection constraint condition set. Then, the function value of the conventional interconnection objective function is optimized based on the conventional interconnection constraint condition set to obtain a conventional interconnection decision value set. Next, a flexible interconnection evaluation model is constructed, wherein the flexible interconnection evaluation model is used to represent an AC interconnected system interconnection and mutual aid capability evaluation model after the flexible interconnection device is put into operation, and the flexible interconnection evaluation model comprises a flexible interconnection objective function and a flexible interconnection constraint condition set. Then, the function value of the flexible interconnection objective function is optimized based on the flexible interconnection constraint condition set to obtain a flexible interconnection decision value set. Finally, the optimal effect of the AC interconnected system is compared based on the conventional interconnection decision value set and the flexible interconnection decision value set on a preset index to obtain comprehensive evaluation data before and after the flexible interconnection device is put into operation, so as to determine the interconnection and mutual aid capability of the AC interconnected system. The method optimizes the objective functions of the conventional interconnection evaluation model and the flexible interconnection evaluation model respectively to obtain the optimal solutions of the two models, ensures that the conventional interconnection and the flexible interconnection have reached the optimal effect, and compares the two on the preset index, so that the interconnection and mutual aid capability of the system under the two interconnection modes can be more accurately reflected. This evaluation mechanism can provide more powerful data support for the optimization of the AC interconnected system.

[0050] According to the embodiments of the application, a method for determining the interconnection and mutual aid capability of an AC interconnected system is provided. It should be noted that the steps shown in the flowchart can be executed in a computer system such as a set of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0051] In this embodiment, a method for determining the interconnection and mutual aid capability of an AC interconnected system is provided. Please refer to Figure 1 The method comprises the following steps:

[0052] S110, a conventional interconnection evaluation model is constructed.

[0053] The conventional interconnection evaluation model is used to represent an AC interconnected system interconnection and mutual aid capability evaluation model before the flexible interconnection device is put into operation, and the conventional interconnection evaluation model comprises a conventional interconnection objective function and a conventional interconnection constraint condition set.

[0054] In some embodiments, when the regional power grids in the AC interconnected system are interconnected in a conventional manner, there can be a situation that some networks have established interconnection while some networks have not established interconnection. Illustratively, the AC interconnected system is composed of AC power grid a and AC power grid b, and the two power grids are interconnected by 500KV high-voltage AC transmission lines, while the 220KV secondary transmission lines are not interconnected, resulting in limited power interconnection and mutual assistance capability between AC power grid a and AC power grid b, and causing part of the power to be unable to be dispatched across regions.

[0055] In some embodiments, the conventional interconnection objective function can be a mathematical expression for quantifying the optimization objective of the AC interconnected system interconnected in a conventional manner, and can be an economic objective. The conventional interconnection constraint condition set can be a set of conditions required to be met during operation of the AC interconnected system interconnected in a conventional manner, and can include limits on voltage, current, power, and the like.

[0056] S120, based on the conventional interconnection constraint condition set, optimizing the function value of the conventional interconnection objective function to obtain a conventional interconnection decision value set.

[0057] In some embodiments, the conventional interconnection decision value set can be a set of optimal decision values obtained by optimizing the conventional interconnection objective function in the conventional interconnection evaluation model.

[0058] In some embodiments, the conventional interconnection objective function in the conventional interconnection evaluation model is optimized, and during the optimization process, the decision variables include load demand , wind power output , photovoltaic output , wind curtailment , light curtailment , and load shedding , and the optimal solution can be effectively found by an optimization algorithm, and the decision variable values in the optimal solution constitute the conventional interconnection decision value set.

[0059] S130, constructing a flexible interconnection evaluation model.

[0060] In some embodiments, the flexible interconnection evaluation model is used to represent the interconnection and mutual assistance capability evaluation model of the AC interconnected system after the flexible interconnection device is put into operation, and the flexible interconnection evaluation model includes a flexible interconnection objective function and a flexible interconnection constraint condition set.

[0061] In some embodiments, a flexible controllable connection is established between regional power grids through a flexible interconnection device. Exemplarily, a flexible DC interconnection device is deployed between a 220KV power grid node of AC power grid a and a 220KV power grid node of AC power grid b, realizing flexible interconnection between power grids of different voltage levels. This device can control the direction and size of active power and reactive power transmission, so that the 220KV networks between AC power grid a and AC power grid b, which are originally not interconnected, can realize flexible power interconnection. In this way, the transmission potential of the 220KV level can be utilized to effectively supplement the transmission capacity of the 500KV main tie line, significantly enhance the power interconnection capacity between the two regional power grids, and reduce the problem of power dispatching limitations caused by tie bottleneck.

[0062] In some embodiments, the flexible interconnection objective function can be a mathematical expression for quantifying the optimization objective of the AC interconnected system interconnected in a flexible manner, and can be an economic objective. The set of flexible interconnection constraint conditions can be a set of conditions that need to be met during the operation of the AC interconnected system interconnected in a flexible manner, and can include limitations on voltage, current, power, etc. Compared with conventional interconnection constraint conditions, the influence of the flexible interconnection device needs to be additionally considered.

[0063] S140, based on the set of flexible interconnection constraint conditions, optimizing the function value of the flexible interconnection objective function to obtain a set of flexible interconnection decision values.

[0064] Among them, the set of flexible interconnection decision values can be a set of optimal decision values obtained by optimizing the flexible interconnection objective function in the flexible interconnection evaluation model.

[0065] In some embodiments, the flexible interconnection objective function in the flexible interconnection evaluation model is optimized. During the optimization process, the decision variables include load demand , wind power output , photovoltaic output , wind curtailment , light curtailment and load shedding . Through the optimization algorithm, the optimal solution can be effectively found, and the decision variable values in the optimal solution constitute the set of flexible interconnection decision values.

[0066] S150, based on the set of conventional interconnection decision values and the set of flexible interconnection decision values, comparing the optimal effects of the AC interconnected system on the preset indicators to obtain comprehensive evaluation data before and after the flexible interconnection device is put into operation, so as to determine the interconnection and interconnection capacity of the AC interconnected system.

[0067] The preset indexes can include a power supply capability index, a source-load tracking coefficient index, a source-load change coefficient index, and a new energy utilization rate index. The optimal effect comparison can be a comparison of the preset indexes when the conventional interconnection and the flexible interconnection have reached an optimal effect (for example, a minimum total cost).

[0068] Specifically, the power supply capability index can be used to evaluate the ability of the AC interconnected system to provide stable power under actual operation constraints, and can be represented by the following formula:

[0069]

[0070] wherein, is the power supply capability of the AC interconnected system, which refers to the sum of the loads that can be supplied by the AC power grid under actual operation constraints. is the actual load of node , is the total number of nodes of the AC interconnected system. is the load set connected to node , is the load demand of the load connected to node , is the load shedding amount of the load connected to node .

[0071] The source-load tracking coefficient index can represent the degree of fitting of the wind and light output curves and the load demand curve, and the greater the value, the higher the degree of fitting. It can be represented by the following formula:

[0072]

[0073] wherein, is the source-load tracking coefficient index, are the values of the load demand, the wind power output, and the photovoltaic output, respectively; , , are the average values of the load demand, the wind power output, and the photovoltaic output, respectively; is the total calculation duration.

[0074] The source-load change coefficient index is used to represent the fluctuation level of the difference between the wind and light output curves and the load demand curve relative to the average value. The greater the value, the greater the fluctuation level of the overall curve relative to the average value. It can be represented by the following formula:

[0075]

[0076] wherein, is the source-load change coefficient index, and are respectively values of load demand, wind power output and photovoltaic output; , , are respectively average values of load demand, wind power output and photovoltaic output; is total calculation duration.

[0077] The new energy utilization rate index reflects the use efficiency of renewable energy (such as solar energy, wind energy, etc.) in the AC interconnected system, and the greater the value, the higher the new energy utilization rate. It can be expressed by the following formula:

[0078]

[0079] wherein, is the new energy utilization rate index, and are respectively wind power output and photovoltaic output; are respectively wind curtailment and light curtailment of the AC interconnected system.

[0080] It can be understood that the conventional interconnection decision value set and the flexible interconnection decision value set both include load demand , wind power output , photovoltaic output , wind curtailment , light curtailment and load shedding , based on the above decision values, the average values , , in a period of time can be calculated, and then the index values of the above preset indexes in the conventional interconnection and the flexible interconnection modes can be calculated.

[0081] In some embodiments, the weight of each preset index is obtained by an objective weight determination method, and then the product of the weight of each preset index and the index value is added as the comprehensive evaluation data. It can be understood that after obtaining two comprehensive evaluation data before and after the input of the flexible interconnection device, the input of the device can be evaluated whether it brings the expected benefit through the comparison of the comprehensive evaluation data.

[0082] It should be noted that the conventional interconnection evaluation model is constructed, and the function value of the conventional interconnection objective function is optimized based on the conventional interconnection constraint condition set, so as to obtain the conventional interconnection decision value set when the optimal effect is achieved in the conventional interconnection mode; the flexible interconnection evaluation model is constructed, and the function value of the flexible interconnection objective function is optimized based on the flexible interconnection constraint condition set, so as to obtain the flexible interconnection decision value set when the optimal effect is achieved in the flexible interconnection mode. Further, the preset index values in the conventional interconnection mode and the flexible interconnection mode are calculated by using the decision values in the conventional interconnection decision value set and the flexible interconnection decision value set respectively, and the comprehensive evaluation data in the two modes is obtained based on the above index values. By comparing the comprehensive evaluation data in the above two modes, the interconnection and mutual aid capability of the alternating current interconnection system can be determined. It should be emphasized that the purpose of this method is to calculate the preset index for evaluating the system based on the optimal effect, that is, the function value of the objective function is optimal (such as the minimum total cost) in the two interconnection modes, and by using the same comparison benchmark of "optimal effect", the comparability of the evaluation between different modes is ensured, and the deviation caused by different optimization degrees is avoided.

[0083] In the above embodiment, first, the conventional interconnection evaluation model is constructed, and the function value of the conventional interconnection objective function is optimized based on the conventional interconnection constraint condition set in the model to obtain the conventional interconnection decision value set, which provides the decision value set in the conventional interconnection mode for optimal effect comparison; then, the flexible interconnection evaluation model is constructed, and the function value of the flexible interconnection objective function is optimized based on the flexible interconnection constraint condition set in the model to obtain the flexible interconnection decision value set, which provides the decision value set in the flexible interconnection mode for optimal effect comparison; finally, based on the decision value sets in the conventional interconnection mode and the flexible interconnection mode, the index values of the preset index in the two modes are obtained, and then the comprehensive evaluation data in the two modes is obtained, the optimal effect comparison in the two modes is realized, and thus the interconnection and mutual aid capability of the alternating current interconnection system can be more accurately determined.

[0084] In some embodiments, the preset index includes a power supply capability index, a source-load tracking coefficient index, a source-load change coefficient index, a new energy utilization rate index, and a short-circuit current index.

[0085] The power supply capability index can reflect the controllable demand of the interconnection capability of the alternating current interconnection system, the short-circuit current index can reflect the short-circuit current suppression demand thereof, and the source-load tracking coefficient index, the source-load change coefficient index, and the new energy utilization rate index can reflect the power supply capability balance demand thereof.

[0086] In particular, the power supply capability index, the source-load tracking coefficient index, the source-load change coefficient index, and the new energy utilization rate index are the same as in S150, and will not be described again here. The short-circuit current index is used to evaluate the maximum current value that may occur in the power grid when an electrical short circuit occurs in the AC interconnected system. By way of example, the short-circuit current calculation before the flexible interconnection device is put into operation can be performed by using the symmetrical component method to solve the short-circuit current size of the interconnected node based on the relevant parameters (branch reactance, generator reactance) of the AC interconnected system.

[0087] After the flexible interconnection device is put into operation, since it has a current limiting control function, when a fault occurs, the flexible interconnection device will limit the short-circuit current, and therefore, during a short circuit, the behavior of the flexible interconnection device can be equivalent to a current source and inject current into the short-circuit point , and the maximum output value is . Since the output current of the flexible interconnection device during a fault is closely related to its low-voltage control strategy, current limiting control strategy, control parameters, and the like, it is difficult to exhaustively calculate, and therefore, when calculating the short-circuit current, the output current amplitude of the flexible interconnection device can be set to a limit value . When a short-circuit fault occurs, first, the influence of the flexible interconnection device is ignored, and the current at the short-circuit point is calculated using the traditional symmetrical component method . Then, the effect of the flexible device is considered, and the total short-circuit current is obtained according to the superposition theorem as follows:

[0088] = +

[0089] wherein, is the short-circuit current, is the output current of the flexible interconnection device, and is the current at the short-circuit point calculated using the traditional symmetrical component method without considering the flexible interconnection device.

[0090] In the above embodiments, the preset indexes cover the three major interconnected and mutual aid scene requirements that need to be addressed by the current AC interconnected system: controllable interconnection capability requirement, short-circuit current suppression requirement, and power supply capability balancing requirement. Compared with the related art which focuses on evaluating a single dimension, the AC interconnected system can be more comprehensively and accurately evaluated.

[0091] In some embodiments, please refer to Figure 2 , a conventional interconnection evaluation model is constructed, including:

[0092] S310, based on the power generation cost, wind curtailment risk cost, light curtailment risk cost, and load shedding risk cost of the AC interconnected system, a conventional interconnection objective function is constructed;

[0093] The objective function for conventional interconnection can be a mathematical expression used to quantify various costs in the operation of an AC interconnection system connected by conventional AC lines without flexible interconnection devices. Generation costs can be the costs required for generators to produce electricity, including fuel costs, maintenance costs, and equipment depreciation. Wind curtailment risk costs can be the economic losses incurred due to the instability and unpredictability of wind power generation, leading to the inability to consume electricity in a timely manner. Solar curtailment risk costs can be the economic losses incurred due to the volatility of photovoltaic power generation, leading to the inability to fully utilize photovoltaic power. Load shedding risk costs can be the risk costs arising from the inability of the AC interconnection system to meet electricity demand in a timely manner due to load fluctuations, potentially requiring emergency load shedding measures.

[0094] In some implementations, the AC interconnection system consists of AC grid a and AC grid b. Before the flexible interconnection device is installed, the two AC grids are interconnected in a conventional manner. Based on this system, a conventional interconnection objective function is constructed, considering power generation costs and risk costs, which can be expressed by the following formula:

[0095]

[0096] Where C represents the total cost. The cost of generating electricity for the generator set, For risk costs.

[0097] Furthermore, the power generation cost of the generator set can be expressed as:

[0098]

[0099] in, A collection of nodes in an interconnected communication system. For nodes A collection of connected generator sets, , , For nodes Connected generator sets Cost consumption characteristic coefficient, For nodes Connected generator sets Power generation capacity.

[0100] Risk costs include wind curtailment risk costs, solar curtailment risk costs, and load shedding risk costs, which can be expressed as:

[0101]

[0102] in, , and They are nodes a wind curtailment penalty cost coefficient, a light curtailment penalty cost coefficient, and a load shedding penalty cost coefficient, , are respectively a wind curtailment amount, a light curtailment amount, and a load shedding amount of the node .

[0103] S320, based on a DC power flow equation constraint, a power flow capacity constraint, a node voltage phase angle constraint, a node power balance constraint, a generator unit output constraint, and a node wind and light curtailment constraint of the AC interconnected system, a conventional interconnected constraint condition set is constructed.

[0104] The conventional interconnected constraint condition set can be a set of constraint conditions for ensuring safe, stable, and efficient operation of the AC interconnected system connected by conventional AC lines.

[0105] In some embodiments, the AC interconnected system is composed of an AC power grid a and an AC power grid b, and before the flexible interconnected device is put into operation, the two AC power grids are interconnected in a conventional manner. Based on this system, a conventional interconnected constraint condition set is constructed, and the constraint conditions contained therein are as follows:

[0106] The DC power flow equation constraint can be a constraint condition in the AC interconnected system representing the flow mode of current in the DC line. Specifically, it can be represented as:

[0107]

[0108] wherein, is a DC power flow, is a circuit admittance between nodes, , represents a voltage phase angle, is a set of AC system line corridors.

[0109] The power flow capacity constraint can be a load capacity constraint condition of the power transmission line in the AC interconnected system. Specifically, it can be represented as:

[0110]

[0111] wherein, is a DC power flow, is the maximum active power transmission power of the line .

[0112] The node voltage phase angle constraint can be represented as:

[0113]

[0114] wherein, and are respectively a minimum value and a maximum value of the node voltage phase angle, is the voltage phase angle of node, N is the set of system nodes.

[0115] The node power balance constraint can be the balance between the generated power and the load power of each node in the AC interconnected system. Specifically, it can be expressed as:

[0116]

[0117] wherein, , , and are the sets of generator units, wind power units, photovoltaic power stations and loads connected to node , is the generated power of the generator units connected to node , is the output power of the wind power units connected to node , is the output power of the photovoltaic power stations connected to node , is the demand power of the loads connected to node , is the amount of wind power and light power that cannot be absorbed, , is the amount of load shedding, , is the DC power flow, , are the line sets with node as the power sending end and receiving end, respectively. The generator unit output constraint can be that the output power of the generator unit must be within a specified range, expressed as:

[0118]

[0119]

[0120] wherein, is the generated power of the generator units connected to node , are the minimum and maximum values of the output power of the generator units, , is the generator unit connected to node . The node wind and light rejection constraint can be the amount of wind and light power that cannot be absorbed, expressed as:

[0121]

[0122] ​​​​​

[0123] wherein, , are the abandoned wind and light amounts of the node , , are the maximum abandoned wind and light ratios allowed by the node , is the output power of the wind turbine connected to the node , is the output power of the photovoltaic power station connected to the node , , , is a node set.

[0124] In some embodiments, a flexible interconnection target function is constructed, comprising:

[0125] Based on the generation cost, abandoned wind risk cost, abandoned light risk cost, load shedding risk cost and flexible interconnection device loss cost of the alternating current interconnection system, a flexible interconnection target function is constructed.

[0126] Wherein, the flexible interconnection target function can be a mathematical expression, which is used to quantify the various costs of the alternating current interconnection system operation after the flexible interconnection device is put into operation. The flexible interconnection device loss cost can be the power loss caused by the operation of the flexible interconnection device.

[0127] In some embodiments, the alternating current interconnection system is composed of alternating current grid a and alternating current grid b, and the two alternating current grids can be flexibly interconnected after the flexible interconnection device is put into operation. Based on this system, the flexible interconnection target function is constructed, which is the same as the conventional interconnection mode, and also considers the generation cost and risk cost, which can be expressed by the formula:

[0128]

[0129] wherein, is the total cost, is the generation cost of the generator set, is the risk cost.

[0130] Further, the generation cost of the generator set can be expressed as:

[0131]

[0132] wherein, is the set of nodes of the alternating current interconnection system, is the set of generator sets connected to the node , , , is the set of nodes Connected generator sets Cost consumption characteristic coefficient, For nodes Connected generator sets Power generation capacity.

[0133] Risk costs include wind curtailment risk costs, solar curtailment risk costs, and load shedding risk costs, which can be expressed as:

[0134]

[0135] in, , , and They are nodes The cost coefficients for wind curtailment, solar curtailment, load shedding, and power loss of flexible interconnect devices. , , They are nodes The amount of wind curtailment, solar curtailment, load shedding, and power loss of flexible interconnect devices. For the number of nodes, A collection of nodes for flexible interconnect devices.

[0136] It should be noted that the objective function of flexible interconnection is the same as that of conventional interconnection, which also considers power generation costs and risk costs. Its purpose is to calculate the preset indicators used to evaluate the system based on the optimal effect, that is, the minimum total cost, in both interconnection modes. By using the same benchmark of objective function, the evaluation between different modes is ensured to be comparable, and deviations caused by different objective functions are avoided.

[0137] In some embodiments, a set of flexible interconnection constraints is constructed, including:

[0138] Based on the constraints of DC power flow equations, power flow capacity, node voltage phase angle, node power balance, generator output, node wind and solar curtailment, active power constraints of flexible interconnection, and capacity constraints of flexible interconnection devices in AC interconnection systems, a set of constraints for flexible interconnection is constructed.

[0139] Among them, the set of constraints for flexible interconnection can be a set of constraints that ensure the safe, stable and efficient operation of an AC interconnection system with flexible interconnection devices. The DC power flow equation constraints, power flow capacity constraints, node voltage phase angle constraints, generator output constraints and node wind and solar curtailment constraints contained therein are the same as the corresponding constraints in the set of constraints for conventional interconnection, and will not be repeated here.

[0140] In some embodiments, the AC interconnection system is composed of AC grid a and AC grid b, and the two AC grids can be flexibly interconnected after the flexible interconnection device is put into operation. The node power balance constraint condition is different from the conventional interconnection constraint condition set, and is specifically as follows:

[0141]

[0142] wherein, , , are the generator set, wind turbine, photovoltaic power station and load set connected with node , is the set of AC grid , is the set of AC grid , and are the line set with node as the power sending end and receiving end respectively. is the generated power of the generator set connected with node , is the active power transmitted by the flexible interconnection device to the th node of AC grid , is the active power transmitted by the flexible interconnection device to the th node of AC grid , is the output power of the wind turbine connected with node , is the output power of the photovoltaic power station pv connected with node , is the demand power of the load connected with node , , and are the wind curtailment, light curtailment and load shedding of node respectively, is the DC power flow.

[0143] Further, the flexible interconnection constraint condition set further includes the flexible interconnection active power constraint and the flexible interconnection device capacity constraint for the flexible interconnection device. Specifically, the flexible interconnection active power constraint can be expressed as:

[0144]

[0145] The flexible interconnection device capacity constraint can be expressed as:

[0146]

[0147] wherein, is the port number of the flexible interconnection device connected to the power grid; , , , are the active and reactive power inputted by the flexible interconnection device to the alternating current power grid respectively; , , is the active power loss of the flexible interconnection device; , is the loss coefficient of the port of the flexible interconnection device; is the capacity of the flexible interconnection device. Please refer to

[0148] and Figure 3 In some embodiments, the method of obtaining the conventional interconnection decision value set is consistent with the method of obtaining the flexible interconnection decision value set; based on the set of flexible interconnection constraint conditions, the function value of the flexible interconnection objective function is optimized to obtain the set of flexible interconnection decision values, including: Figure 4 S610, differential evolution algorithm is performed on the initial particle swarm to obtain a differential evolution particle swarm.

[0149] wherein, the differential evolution algorithm includes mutation, crossover and selection. The initial particle swarm can be a set of initial particles obtained by initializing the population, and each particle can be a multi-dimensional vector, and the elements in the vector include load demand

[0150] , wind power output , photovoltaic output , wind curtailment , light curtailment and load shedding amount .

[0151] In some embodiments, the fitness value of each initial particle in the initial particle swarm is first calculated, and the fitness function can be the flexible interconnection objective function; then the fitness value of each initial particle is taken as its optimal fitness value, and the minimum fitness value is selected from the fitness values of all initial particles as the population optimal fitness value; then the mutation algorithm is performed on each initial particle, and the formula is as follows:

[0152]

[0153] wherein, is the mutation particle, and W is the mutation factor, which can be used to adjust the amplitude of mutation; , , ​respectively. Specifically, using the above formula, a mutation particle is generated for each initial particle of the initial particle group.

[0154] Further, the mutation particle and the initial particle are crossed to generate a crossover particle, and the formula is as follows:

[0155]

[0156] wherein, is the crossover particle, is the initial particle, is the mutation particle, may be a random number in the interval [0, 1], is the crossover probability, ∈[0, 1]. Specifically, using the above formula, a crossover particle is obtained for each initial particle of the initial particle group.

[0157] Further, the crossover particle and the initial particle are compared using a greedy strategy to obtain a differential evolution particle. The formula is as follows:

[0158]

[0159] wherein, is the differential evolution particle, is the crossover particle, is the initial particle, is the fitness function, in the embodiment, is the flexible interconnection target function . It can be understood that after comparing the fitness of the crossover particle and the initial particle, the particle with the smaller fitness value is selected as the differential evolution particle.

[0160] Finally, the fitness value of each differential evolution particle in the differential evolution particle group is calculated, and then the optimal fitness value of each differential evolution particle and the population optimal fitness value are updated.

[0161] S620, based on the concentration probability of each particle in the differential evolution particle group, a target difference particle group is selected.

[0162] wherein, the concentration probability can be a probability value based on the concentration of the differential evolution particle. The concentration of the differential evolution particle is used to represent the similarity degree of any differential evolution particle to other particles in the differential evolution particle group. Specifically, the higher the similarity degree of any differential evolution particle to other particles in the differential evolution particle group, the greater the concentration, and the smaller the concentration probability. The target difference particle group can be a particle group composed of particles with high concentration probability, i.e. particles with low similarity degree, selected from the differential evolution particle group. The diversified particle group is helpful to avoid falling into a local optimal solution when optimizing.

[0163] In some embodiments, the formula for calculating the concentration of particles is:

[0164]

[0165] wherein, is the concentration of the current differential evolution particle, is the fitness of the current differential evolution particle, is the fitness of other particles in the differential evolution particle group, is the number of particles in the differential evolution particle group.

[0166] Further, the concentration probability of the current differential evolution particle is calculated using the following formula:

[0167]

[0168] wherein, is the concentration probability of the current differential evolution particle, is the concentration of the current differential evolution particle, is the number of particles in the differential evolution particle group.

[0169] Still further, after the concentration probability of each differential evolution particle is calculated, the half of the particles with higher concentration probability are selected to form the target difference particle group. It can be understood that the more similar particles the differential evolution particle has, the smaller the probability of being selected. Conversely, the fewer similar particles the differential evolution particle has, the greater the probability of being selected. Therefore, the selection mechanism based on the concentration probability of particles can enhance the diversity of the population and effectively avoid falling into a local optimal solution.

[0170] S630, performing global search based on the target difference particle group to obtain a target particle that minimizes the function value of the flexible interconnection target function, and determining a flexible interconnection decision value set.

[0171] Wherein, the global search can be optimization using an algorithm with good global search performance.

[0172] In some embodiments, first, the parameters in the improved particle swarm algorithm are initialized, such as the learning factor, the maximum number of particle swarm iterations (the number of iterations performed by the improved particle swarm algorithm once), the convergence precision, the upper and lower limits of the speed, the particle speed, etc. Then, the target difference particle group is input into the improved particle swarm algorithm for global search, and the following formula is used for speed and position update:

[0173]

[0174] ​​

[0175] in, For the first The velocity of the target difference particles , The learning factor (e.g., a value of 2). , A random number in the interval (0,1). For the first The optimal fitness value of each target differential particle. This represents the optimal fitness value for the population. For the first The positions of the target difference particles, w is the nonlinear dynamic adaptive inertia weight, which is calculated as follows:

[0176]

[0177] in, As a control factor, it can control the inertia weight. The size of the value, The maximum number of iterations, This represents the current iteration number. , These are the start and end weights, respectively. For example, The value is 0.9. The value is set to 0.4. Compared with fixed weights, this nonlinear dynamic adaptive inertial weight can adapt to different search requirements at different stages, which can improve the global search capability and prevent the algorithm from getting trapped in local optima.

[0178] Furthermore, the current fitness value of each particle after the update is calculated, and each particle's current fitness value is compared with its best fitness value. If the current fitness value is smaller, its best fitness value is used as the best fitness value, and the current position is the best position for that particle. Additionally, for each particle, its best fitness value is compared with the population's best fitness value. If the particle's best fitness value is smaller, the population's best position and best fitness value are updated. It is important to note that updating the population's best position must satisfy the constraints of the flexible interconnection constraint set.

[0179] Furthermore, determine whether the stopping condition is met, such as reaching the maximum number of iterations (the number of iterations from the differential evolution solution to the completion of the particle swarm optimization algorithm). If so, output the optimal solution, i.e., the optimal position of the population. Otherwise, continue the optimization process through steps S610-S630.

[0180] Finally, the load demand is obtained from the optimal solution. Wind power output Photovoltaic power output , wind curtailment , light curtailment , cut load , to obtain a flexible interconnection decision value set.

[0181] It should be noted that the method of obtaining the conventional interconnection decision value set is consistent with the method of obtaining the flexible interconnection decision value set. The purpose is to achieve the optimal effect under the two interconnection modes based on the same method. By using the same comparison standard of "the same method", the evaluation between different modes is ensured to be comparable, and the deviation caused by different optimization methods is avoided.

[0182] In the above embodiment, first, the initial particle swarm is solved by differential evolution to improve the diversity of the particles, and a differential evolution particle swarm is obtained. Then, based on the concentration probability of each particle in the differential evolution particle swarm, a target difference particle swarm is selected, and the concentration probability is used to further improve the diversity of the particles. Finally, based on the diversified target difference particle swarm, a global search is performed to obtain the optimal solution, thereby determining the flexible interconnection decision value set. This method not only improves the particle diversity through differential evolution and concentration probability, effectively avoiding the algorithm from falling into local extremum, but also improves the convergence speed in global search through nonlinear dynamic self-adaptive inertia weight, further avoiding the algorithm from falling into local extremum, and quickly finding the optimal flexible interconnection decision value set.

[0183] In some embodiments, referring to Figure 5 , the preset indicators include power supply capability indicators, source-load tracking coefficient indicators, source-load change coefficient indicators, new energy utilization rate indicators, and short-circuit current indicators. Based on the optimal effect comparison of the alternating current interconnection system on the preset indicators between the conventional interconnection decision value set and the flexible interconnection decision value set, comprehensive evaluation data before and after the flexible interconnection device is put into operation is obtained, including:

[0184] S710, based on the index values of the power supply capability indicators, the source-load tracking coefficient indicators, the source-load change coefficient indicators, the new energy utilization rate indicators, and the short-circuit current indicators before and after the flexible interconnection device is put into operation, an initial evaluation matrix is constructed.

[0185] Among them, the evaluation elements on the first specified row in the initial evaluation matrix are used to represent each preset indicator before the flexible interconnection device is put into operation; the evaluation elements on the second specified row in the initial evaluation matrix are used to represent each preset indicator after the flexible interconnection device is put into operation;

[0186] In some embodiments, first, the index values of the power supply capability indicators, the source-load tracking coefficient indicators, the source-load change coefficient indicators, the new energy utilization rate indicators, and the short-circuit current indicators before and after the flexible interconnection device is put into operation are obtained, and an initial evaluation matrix is constructed, wherein, represents the first sample of the initial evaluation matrix The values ​​of each indicator .

[0187] S720. Normalize the value of each element to be evaluated in the initial matrix to be evaluated to obtain the target matrix to be evaluated.

[0188] In some implementations, for negative indicators (short-circuit current indicators, source load variation coefficient indicators), their reciprocals are taken to convert them into positive indicators, ensuring that all indicators are in the same direction. Then, all indicators are normalized using the following formula:

[0189]

[0190] in, express The normalized index values ​​are obtained by normalizing the values ​​of each element in the initial matrix to be evaluated, thus obtaining the target matrix to be evaluated.

[0191] S730. Based on the value of each element to be evaluated in the target evaluation matrix, a weighted standard value is obtained by weighting the values.

[0192] In some implementations, the formula for weighted calculation is as follows:

[0193]

[0194] in, Let the values ​​of the elements to be evaluated in the target evaluation matrix be denoted as . For weighted standard values, For the first The weights of each indicator can be preset based on its actual impact on system security / economy, for example... .

[0195] S740. Based on the weighted standard value of each element to be evaluated, obtain the distance from each weighted standard value to the positive ideal solution and the negative ideal solution.

[0196] In some implementations, the formulas for calculating the positive and negative ideal solutions are as follows:

[0197]

[0198]

[0199] in, For the first The positive ideal solution of the indicator, For the first The negative ideal solution of the indicator.

[0200] Furthermore, the distances from each weighted standard value to the positive and negative ideal solutions are obtained using the following formulas:

[0201]

[0202]

[0203] in, For the first The distance between each sample and the positive ideal solution For the first The distance between each sample and the negative ideal solution.

[0204] S750. Based on the distances from each weighted standard value to the positive and negative ideal solutions, comprehensive evaluation data before and after the flexible interconnection device is put into use is obtained.

[0205] In some implementations, the comprehensive evaluation data before and after the deployment of the flexible interconnect device is obtained using the following formula:

[0206]

[0207] in, For the first The comprehensive evaluation data of each sample. For example, the sample data before the flexible interconnection device is deployed is in the first row of the initial evaluation matrix, representing the first sample; the sample data after the flexible interconnection device is deployed is in the second row of the initial evaluation matrix, representing the second sample; after processing in steps S720-S750, the following is obtained: This is comprehensive evaluation data before the deployment of flexible interconnected devices. This is the comprehensive evaluation data after the flexible interconnection device is put into use. The comprehensive evaluation data ranges from [0,1]. The closer the value is to 1, the better the current solution performs in meeting the requirements of controllable interconnection capability, short-circuit current suppression, and balanced power supply capability of the AC interconnection system.

[0208] In the above embodiments, by calculating the comprehensive evaluation data of interconnection and mutual assistance capabilities, the overall impact of flexible interconnection devices on interconnection power supply capabilities, short-circuit suppression, source-load matching, and other dimensions can be quantified, providing a more accurate basis for planning and decision-making of AC interconnection systems.

[0209] In some embodiments, based on the conventional interconnection decision value set and the flexible interconnection decision value set, the values ​​of preset indicators before and after the flexible interconnection device is obtained, including power supply capacity indicators, source-load tracking coefficient indicators, source-load change coefficient indicators, renewable energy utilization rate indicators, and short-circuit current indicators. Next, the power supply capacity improvement rate indicator and the short-circuit current limiting efficiency indicator are calculated. The calculation formula for the power supply capacity improvement rate indicator is as follows:

[0210]

[0211] is the power supply capacity improvement rate, which is used to represent the improvement effect of the flexible interconnection device on the power supply capacity of the AC interconnected system; and are the system power supply capacities before and after the flexible interconnection device is put into operation, respectively.

[0212] The calculation formula of the short-circuit current limiting efficiency index is as follows:

[0213]

[0214] is the short-circuit current limiting efficiency, and are the system short-circuit currents before and after the flexible interconnection device is put into operation, respectively.

[0215] In some embodiments, the interconnection and mutual aid capacity of the AC interconnected system is determined by the power supply capacity improvement rate index, the short-circuit current limiting efficiency index, the source-load tracking coefficient index before the flexible interconnection device is put into operation , the source-load change coefficient index , the new energy utilization rate index , the source-load tracking coefficient index after the flexible interconnection device is put into operation , the source-load change coefficient index , and the new energy utilization rate index , specifically as follows:

[0216] If > 0, it indicates that the flexible interconnection device has an improvement effect on the power supply capacity of the AC interconnected system, otherwise it indicates that it does not have an improvement effect;

[0217] If > 0, it indicates that the flexible interconnection device has a limiting effect on the short-circuit current of the interconnected node of the AC interconnected system, otherwise it indicates that it does not have a limiting effect;

[0218] If , it indicates that the flexible interconnection device can improve the fitting degree of the wind and light output curve and the load demand curve of the AC interconnected system, otherwise it indicates that it cannot improve the fitting degree;

[0219] If < 0 , it indicates that the flexible interconnection device can reduce the fluctuation level of the difference between the wind and light output curve and the load demand curve of the AC interconnected system relative to its average value, otherwise it indicates that it cannot reduce the fluctuation level;

[0220] If > 0 If the result is true, it indicates that the flexible interconnection device can improve the utilization rate of wind and solar resources of the AC interconnected system, otherwise, it indicates that the utilization rate cannot be improved.

[0221] Please refer to Figure 6 The embodiment of the present application also provides an interconnection and mutual aid capability determination device 800 of an AC interconnected system, the interconnection and mutual aid capability determination device 800 of the AC interconnected system comprising:

[0222] A conventional model construction module 810 is configured to construct a conventional interconnection evaluation model; wherein the conventional interconnection evaluation model is configured to represent an interconnection and mutual aid capability evaluation model of the AC interconnected system before the flexible interconnection device is put into operation, and the conventional interconnection evaluation model comprises a conventional interconnection objective function and a conventional interconnection constraint condition set;

[0223] A conventional objective function optimization module 820 is configured to optimize the function value of the conventional interconnection objective function based on the conventional interconnection constraint condition set, and obtain a conventional interconnection decision value set;

[0224] A flexible model construction module 830 is configured to construct a flexible interconnection evaluation model; wherein the flexible interconnection evaluation model is configured to represent an interconnection and mutual aid capability evaluation model of the AC interconnected system after the flexible interconnection device is put into operation, and the flexible interconnection evaluation model comprises a flexible interconnection objective function and a flexible interconnection constraint condition set;

[0225] A flexible objective function optimization module 840 is configured to optimize the function value of the flexible interconnection objective function based on the flexible interconnection constraint condition set, and obtain a flexible interconnection decision value set;

[0226] An interconnection and mutual aid capability determination module 850 is configured to compare the optimal effects of the AC interconnected system based on the conventional interconnection decision value set and the flexible interconnection decision value set on a preset index, and obtain comprehensive evaluation data before and after the flexible interconnection device is put into operation, so as to determine the interconnection and mutual aid capability of the AC interconnected system.

[0227] In some embodiments, the interconnection and mutual aid capability determination module 850 is provided with a preset index unit, and the preset index unit comprises the following indexes: a power supply capability index, a source-load tracking coefficient index, a source-load change coefficient index, a new energy utilization rate index, and a short-circuit current index.

[0228] In some embodiments, the conventional model construction module 810 comprises:

[0229] A conventional objective function construction unit is configured to construct a conventional interconnection objective function based on the power generation cost, the wind curtailment risk cost, the light curtailment risk cost, and the load shedding risk cost of the AC interconnected system;

[0230] A conventional constraint condition construction unit is configured to construct a conventional interconnection constraint condition set based on DC power flow equation constraints, power flow capacity constraints, node voltage phase angle constraints, node power balance constraints, generator set output constraints, and node wind and light curtailment constraints of the AC interconnected system.

[0231] In some embodiments, the flexible model construction module 830 includes:

[0232] A flexible target function construction unit is configured to construct a flexible interconnection target function based on generation cost, wind curtailment risk cost, light curtailment risk cost, load shedding risk cost, and flexible interconnection device loss cost of the AC interconnected system.

[0233] In some embodiments, the flexible model construction module 830 includes:

[0234] A flexible constraint condition construction unit is configured to construct a flexible interconnection constraint condition set based on DC power flow equation constraints, power flow capacity constraints, node voltage phase angle constraints, node power balance constraints, generator set output constraints, node wind and light curtailment constraints, flexible interconnection active power constraints, and flexible interconnection device capacity constraints of the AC interconnected system.

[0235] In some embodiments, the method of obtaining the conventional interconnection decision value set and the flexible interconnection decision value set is consistent; the flexible target function optimization module 840 includes:

[0236] A difference solution unit is configured to perform differential evolution solution on the initial particle swarm to obtain a differential evolution particle swarm; wherein the differential evolution solution includes mutation, crossover, and selection.

[0237] A difference particle selection unit is configured to select a target difference particle swarm based on the concentration probability of each particle in the differential evolution particle swarm.

[0238] A decision value determination unit is configured to perform global search based on the target difference particle swarm to obtain a target particle that minimizes the function value of the flexible interconnection target function, and determine the flexible interconnection decision value set.

[0239] In some embodiments, the preset indicators include power supply capacity indicators, source-load tracking coefficient indicators, source-load change coefficient indicators, new energy utilization rate indicators, and short-circuit current indicators; and the interconnection and mutual assistance capability determination module 850 includes:

[0240] An initial matrix construction unit is configured to construct an initial to-be-evaluated matrix based on the index values of the power supply capability index, the source-load tracking coefficient index, the source-load change coefficient index, the new energy utilization rate index and the short-circuit current index before and after the flexible interconnection device is put into operation; wherein, the to-be-evaluated elements on the first designated row in the initial to-be-evaluated matrix are used to represent each preset index before the flexible interconnection device is put into operation; the to-be-evaluated elements on the second designated row in the initial to-be-evaluated matrix are used to represent each preset index after the flexible interconnection device is put into operation;

[0241] A target matrix acquisition unit is configured to normalize the values of each to-be-evaluated element in the initial to-be-evaluated matrix to obtain a target to-be-evaluated matrix.

[0242] A weighted standard value acquisition unit is configured to perform weighted calculation based on the values of each to-be-evaluated element in the target to-be-evaluated matrix to obtain a weighted standard value.

[0243] A distance acquisition unit is configured to obtain the distance from each weighted standard value to the positive ideal solution and the negative ideal solution based on the weighted standard value of each to-be-evaluated element.

[0244] An evaluation data acquisition unit is configured to obtain comprehensive evaluation data before and after the flexible interconnection device is put into operation based on the distance from each weighted standard value to the positive ideal solution and the negative ideal solution.

[0245] The further function description of each module and unit is the same as the corresponding embodiment described above, and will not be repeated here.

[0246] The interconnection and mutual aid capability determination device of the alternating current interconnection system in the embodiment is presented in the form of a functional unit. The unit here refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and a memory executing one or more software or fixed programs, and / or other devices that can provide the above functions.

[0247] Please refer to Figure 7 , Figure 7 is a structural schematic diagram of a computer device provided by the embodiment of the present application, such as Figure 7As shown, the computer device includes one or more processors 10, memory 20, and interfaces for connecting the components, including high-speed interfaces and low-speed interfaces. The components communicate with each other via different buses and can be mounted on a common motherboard or otherwise installed as needed. The processors can process instructions executed within the computer device, including instructions stored in or on memory to display graphical information of a GUI on external input / output devices (such as display devices coupled to the interfaces). In some alternative implementations, multiple processors and / or multiple buses can be used with multiple memories and multiple memory modules, if desired. Similarly, multiple computer devices can be connected, each providing some of the necessary operations (e.g., as a server array, a group of blade servers, or a multiprocessor system). Figure 7 Take a processor 10 as an example.

[0248] Processor 10 may be a central processing unit, a network processor, or a combination thereof. Processor 10 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The programmable logic device may be a complex programmable logic device (CAMP), a field-programmable gate array (FPGA), a general-purpose array logic (GDA), or any combination thereof.

[0249] The memory 20 stores instructions executable by at least one processor 10 to cause the at least one processor 10 to perform the method shown in the above embodiments.

[0250] The memory 20 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the computer device. Furthermore, the memory 20 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some alternative embodiments, the memory 20 may optionally include memory remotely located relative to the processor 10, which can be connected to the computer device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0251] The memory 20 may include volatile memory, such as random access memory; the memory may also include non-volatile memory, such as flash memory, hard disk or solid-state drive; the memory 20 may also include a combination of the above types of memory.

[0252] The computer device also includes an input device 30 and an output device 40. The processor 10, the memory 20, the input device 30 and the output device 40 can be connected through a bus or other means, Figure 7 The bus connection is taken as an example.

[0253] The input device 30 can receive inputted digital or character information, and generate key signal input related to user settings and function control of the computer device, such as touch screen, keypad, mouse, trackpad, touchpad, pointing stick, one or more mouse buttons, trackball, joystick, etc. The output device 40 can include display device, auxiliary lighting device (e.g. LED), and tactile feedback device (e.g. vibration motor), etc. The display device includes but is not limited to liquid crystal display, light emitting diode, display and plasma display. In some optional embodiments, the display device can be a touch screen.

[0254] The embodiments of the present application further provide a computer readable storage medium, and the method according to the embodiments of the present application can be implemented in hardware, firmware, or recorded in a storage medium, or be implemented as computer code originally stored in a remote storage medium or non-transitory machine readable storage medium and downloaded to a local storage medium, so that the method described herein can be processed by such software on a storage medium using a general purpose computer, a special purpose processor, or programmable or special purpose hardware. The storage medium can be a magnetic disk, an optical disk, a read-only memory, a random access memory, a flash memory, a hard disk or a solid state disk, etc. Further, the storage medium can also include a combination of the above-mentioned memories. It can be understood that the computer, the processor, the microprocessor controller or the programmable hardware include a storage component that can store or receive software or computer code, when the software or computer code is accessed and executed by the computer, the processor or the hardware, the method shown in the above embodiments is implemented.

[0255] The embodiments of the present application provide a computer program product, which includes computer instructions stored in a computer readable storage medium. The processor of the computer device reads the computer instructions from the computer readable storage medium, and the processor executes the computer instructions, so that the computer device executes the method of any embodiment of the present application.

[0256] Although the embodiments of the present application are described in conjunction with the accompanying drawings, various modifications and changes can be made by those skilled in the art without departing from the spirit and scope of the present application, and such modifications and changes fall within the scope defined by the appended claims.

[0257] The systems, apparatuses, modules, or units disclosed in the above embodiments can be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer. Specifically, the computer can be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

[0258] For the sake of description, the above apparatuses are described in various units respectively according to functions. Of course, the functions of the units can be implemented in one or more software and / or hardware in the implementation of the present application.

[0259] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage devices, etc.) containing computer-usable program code.

[0260] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing apparatus to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing apparatus produce a device implemented in accordance with the flowcharts and / or block diagrams. Figure 1 The device that implements the function specified in one flow or multiple flows and / or blocks. Figure 1 The device that implements the function specified in one block or multiple blocks.

[0261] These computer program instructions can also be stored in a computer-readable memory that can direct the computer or other programmable data processing apparatus to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction device that implements the flowcharts and / or block diagrams. Figure 1 The device that implements the function specified in one flow or multiple flows and / or blocks. Figure 1 The device that implements the function specified in one block or multiple blocks.

[0262] These computer program instructions can also be loaded into a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 Figure 1 Figure 1

[0263] It should also be noted that the term "comprising" or "comprises" when used in this specification is taken to mean the term "including" or "includes" such that the process, method, article, or apparatus that comprises items includes those items but is not limited to those items.

[0264] Each of the embodiments in the present specification is described in a progressive manner, and the same or similar parts between the embodiments can be mutually referred to. Each of the embodiments mainly explains the difference from other embodiments. In particular, the system embodiments are described simply because they are basically similar to the method embodiments, and the relevant parts can be referred to the part of the method embodiments.

[0265] The above only describes the embodiments of the present application and is not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the scope of the claims of the present application.

[0266] Although the embodiments of the present application are described in conjunction with the drawings, various modifications and changes can be made by those skilled in the art without departing from the spirit and scope of the present application, and such modifications and changes should fall within the scope defined by the appended claims.​​

Claims

1. A method for determining the interconnection capability of an alternating current interconnection system, characterized by, The method comprises: constructing a conventional interconnection evaluation model; wherein the conventional interconnection evaluation model is used to represent an alternating current interconnection system interconnection and mutual aid capability evaluation model before the flexible interconnection device is put into operation, and the conventional interconnection evaluation model comprises a conventional interconnection objective function and a conventional interconnection constraint condition set; based on the conventional interconnection constraint condition set, the function value of the conventional interconnection objective function is optimized to obtain a conventional interconnection decision value set; constructing a flexible interconnection evaluation model; wherein the flexible interconnection evaluation model is used to represent an alternating current interconnection system interconnection and mutual aid capability evaluation model after the flexible interconnection device is put into operation, and the flexible interconnection evaluation model comprises a flexible interconnection objective function and a flexible interconnection constraint condition set; based on the flexible interconnection constraint condition set, the function value of the flexible interconnection objective function is optimized to obtain a flexible interconnection decision value set; wherein the method of obtaining the conventional interconnection decision value set and the flexible interconnection decision value set is consistent; the flexible interconnection decision value set is obtained by the following method, comprising: differential evolution calculation is performed on the initial particle swarm to obtain a differential evolution particle swarm; wherein the differential evolution calculation comprises variation, crossover and selection; based on the concentration probability of each particle in the differential evolution particle swarm, a target difference particle swarm is selected; based on the target difference particle swarm, global search is performed to obtain a target particle that minimizes the function value of the flexible interconnection objective function, and the flexible interconnection decision value set is determined; based on the conventional interconnection decision value set and the flexible interconnection decision value set, optimal effect comparison of the alternating current interconnection system is performed on a preset index to obtain comprehensive evaluation data before and after the flexible interconnection device is put into operation, so as to determine the interconnection and mutual aid capability of the alternating current interconnection system; wherein the preset index comprises: a power supply capability index, a source and load tracking coefficient index, a source and load change coefficient index, a new energy utilization rate index and a short-circuit current index.

2. The method of claim 1, wherein, The conventional interconnection evaluation model is constructed, comprising: based on the generation cost, the wind curtailment risk cost, the light curtailment risk cost and the load shedding risk cost of the alternating current interconnection system, the conventional interconnection objective function is constructed; based on the direct current power flow equation constraint, the power flow capacity constraint, the node voltage phase angle constraint, the node power balance constraint, the generator unit output constraint and the node wind and light curtailment constraint of the alternating current interconnection system, the conventional interconnection constraint condition set is constructed.

3. The method of claim 1, wherein, The flexible interconnection objective function is constructed, comprising: based on the generation cost, the wind curtailment risk cost, the light curtailment risk cost, the load shedding risk cost and the flexible interconnection device loss cost of the alternating current interconnection system, the flexible interconnection objective function is constructed.

4. The method of claim 3, wherein, The flexible interconnection constraint condition set is constructed, comprising: based on the direct current power flow equation constraint, the power flow capacity constraint, the node voltage phase angle constraint, the node power balance constraint, the generator unit output constraint, the node wind and light curtailment constraint, the flexible interconnection active power constraint and the flexible interconnection device capacity constraint of the alternating current interconnection system, the flexible interconnection constraint condition set is constructed.

5. The method of claim 1, wherein, The optimal effect comparison of the alternating current interconnection system is performed on a preset index based on the conventional interconnection decision value set and the flexible interconnection decision value set, and comprehensive evaluation data before and after the flexible interconnection device is put into operation is obtained, including: Based on the index values of the power supply capacity index, the source-load tracking coefficient index, the source-load change coefficient index, the new energy utilization rate index and the short-circuit current index before and after the flexible interconnection device is put into operation, an initial evaluation matrix is constructed; wherein, the evaluation elements on the first designated row in the initial evaluation matrix are used to represent each preset index before the flexible interconnection device is put into operation; the evaluation elements on the second designated row in the initial evaluation matrix are used to represent each preset index after the flexible interconnection device is put into operation; The values of each evaluation element in the initial evaluation matrix are normalized to obtain a target evaluation matrix; Based on the values of each evaluation element in the target evaluation matrix, a weighted standard value is calculated; Based on the weighted standard value of each evaluation element, the distance of each weighted standard value to the positive ideal solution and the negative ideal solution is obtained; Based on the distance of each weighted standard value to the positive ideal solution and the negative ideal solution, the comprehensive evaluation data before and after the flexible interconnection device is put into operation is obtained.

6. A device for determining the interconnection and mutual assistance capability of an AC interconnection system, characterized in that, The device comprises: A conventional model construction module is configured to construct a conventional interconnection evaluation model; wherein, the conventional interconnection evaluation model is used to represent an alternating current interconnection system interconnection and mutual benefit capability evaluation model before a flexible interconnection device is put into operation, and the conventional interconnection evaluation model comprises a conventional interconnection objective function and a conventional interconnection constraint condition set; A conventional objective function optimization module is configured to optimize the function value of the conventional interconnection objective function based on the conventional interconnection constraint condition set, and obtain a conventional interconnection decision value set; A flexible model construction module is configured to construct a flexible interconnection evaluation model; wherein, the flexible interconnection evaluation model is used to represent an alternating current interconnection system interconnection and mutual benefit capability evaluation model after the flexible interconnection device is put into operation, and the flexible interconnection evaluation model comprises a flexible interconnection objective function and a flexible interconnection constraint condition set; A flexible objective function optimization module is configured to optimize the function value of the flexible interconnection objective function based on the flexible interconnection constraint condition set, and obtain a flexible interconnection decision value set; wherein, the method of obtaining the conventional interconnection decision value set and the method of obtaining the flexible interconnection decision value set are consistent; the flexible interconnection decision value set is obtained by the following method, including: performing differential evolution calculation on an initial particle swarm to obtain a differential evolution particle swarm; wherein, the differential evolution calculation includes variation, crossover and selection; based on the concentration probability of each particle in the differential evolution particle swarm, a target difference particle swarm is selected; based on the target difference particle swarm, a global search is performed to obtain a target particle that minimizes the function value of the flexible interconnection objective function, and the flexible interconnection decision value set is determined; The interconnection and mutual aid capability determination module is configured to perform optimal effect comparison on the AC interconnection system based on the conventional interconnection decision value set and the flexible interconnection decision value set on preset indexes, to obtain comprehensive evaluation data before and after the flexible interconnection device is put into operation, and to determine the interconnection and mutual aid capability of the AC interconnection system; wherein the preset indexes include a power supply capability index, a source-load tracking coefficient index, a source-load change coefficient index, a new energy utilization rate index, and a short-circuit current index.

7. A computer device, comprising: The computer readable storage medium has stored thereon computer instructions for causing a computer to perform the method of any one of claims 1 to 5. The computer readable storage medium has stored thereon computer instructions for causing a computer to perform the method of any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, ​

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