Active power distribution network loop closing control method and device and electronic equipment

Abstract

The invention belongs to the field of active power distribution networks, and provides an active power distribution network loop closing control method and device and electronic equipment, and the method comprises the steps: obtaining the operation data and load data of a distributed power supply; performing Latin hypercube sampling to obtain a photovoltaic semi-invariant and a load semi-invariant; performing matrix transformation and series expansion on the photovoltaic semi-invariant and the load semi-invariant to obtain a cumulative distribution function and a probability density function of the loop closing current; acquiring key current data of feeder lines on two sides of a loop closing point under different loop closing operation strategies, and inputting the key current data into the cumulative distribution function and the probability density function to obtain a safety evaluation index value; and taking the loop closing operation strategy with the optimal safety evaluation index value as a target loop closing operation strategy, and performing loop closing control on the active power distribution network according to the target loop closing operation strategy. The security evaluation index value of each loop closing operation strategy is determined through Latin hypercube sampling and series expansion, and the security and reliability of the loop closing process are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of active power distribution networks, and in particular to a closed-loop control method, device and electronic equipment for an active power distribution network. Background Art

[0002] An active distribution network refers to a distribution network that includes distributed power sources. In addition to distributed power sources, an active distribution network also includes distribution lines, distribution transformers, various switchgear, reactive power compensation devices, and smart meters, communication equipment, and control systems for monitoring and control. When a distribution line in an active distribution network fails and needs to be handled, or when maintenance work is carried out as planned, loop closing operation is an effective response measure that can achieve load transfer without interrupting power supply, minimizing the impact on user electricity consumption.

[0003] In the related technology, during the closing process, since steady-state circulating current and impact current are very likely to be generated, these abnormal current conditions may cause the protection device to malfunction and cause the distribution line to overload, thus posing a serious threat to the safe and stable operation of the entire power system. At the same time, when performing closing calculations, traditional analysis schemes based on deterministic parameters and relatively stable working conditions are difficult to effectively evaluate the safety of the closing process, which easily leads to low safety and insufficient reliability of closing control. Summary of the invention

[0004] The present invention provides a closed-loop control method, device and electronic equipment for an active power distribution network, which are used to solve the defects of low safety and insufficient reliability of traditional closed-loop control solutions.

[0005] In one aspect, the present invention provides an active distribution network closed-loop control method, comprising: Obtaining the operating data and load data of distributed power sources in the closed-ring network topology of the active distribution network; Performing Latin hypercube sampling on the operation data and load data of the distributed power source to obtain photovoltaic semi-invariants and load semi-invariants; Performing matrix transformation and series expansion on the photovoltaic semi-invariant and the load semi-invariant to obtain a cumulative distribution function and a probability density function of the closed-loop current; Acquire key current data of feeders on both sides of the closing point under different closing operation strategies, and input the key current data into the cumulative distribution function and the probability density function to obtain the safety assessment index value corresponding to each closing operation strategy; The closed-loop operation strategy with the best safety evaluation index value is used as the target closed-loop operation strategy, and the active distribution network is closed-loop controlled according to the target closed-loop operation strategy.

[0006] According to the closed-loop control method for an active distribution network provided by the present invention, matrix transformation and series expansion are performed on the photovoltaic semi-invariant and the load semi-invariant to obtain a cumulative distribution function and probability density of the closed-loop current, including: Based on the operation data and load data of the distributed power source, a network power flow calculation is performed at a reference operation point to obtain a power flow calculation result; Adding the photovoltaic semi-invariant and the load semi-invariant to calculate the node injection power accumulation; Based on the power flow calculation result, matrix transformation is performed on the accumulated amount of power injected into the node to calculate the semi-invariant of the closed-loop current; The semi-invariant of the closed-loop current is expanded in series, and the cumulative distribution function and probability density function of the closed-loop current are obtained by fitting.

[0007] According to the active distribution network closed-loop control method provided by the present invention, the key current data is input into the cumulative distribution function and the probability density function to obtain the safety assessment index value corresponding to each closed-loop operation strategy, including: Inputting the first key sub-data in the key current data into the cumulative distribution function, and calculating the preliminary loop closing success rate according to the function output value; When the initial closing loop success rate is higher than the preset success rate threshold, the second key sub-data in the key current data under each closing loop operation strategy is input into the probability density sub-function to calculate the maximum over-limit rate and average over-line rate of the closing loop current; The initial loop closing success rate, the maximum limit crossing rate and the average line crossing rate are used as safety evaluation index values ​​corresponding to each loop closing operation strategy.

[0008] According to the active distribution network closed-loop control method provided by the present invention, the first key sub-data includes: a first maximum current carrying capacity, a second maximum current carrying capacity, a first current quick-break protection setting value, and a second current quick-break protection setting value of the feeders on both sides of the closed-loop point; The second key sub-data includes: closed-loop current and preset rated current; The cumulative distribution function includes: a first cumulative distribution sub-function corresponding to the first closed-loop steady-state current of the feeders on both sides of the closed-loop point, a second cumulative distribution sub-function corresponding to the second closed-loop steady-state current, a third cumulative distribution sub-function corresponding to the first closed-loop transient current, and a fourth cumulative distribution sub-function corresponding to the second closed-loop transient current.

[0009] According to the active distribution network closed-loop control method provided by the present invention, the first key sub-data in the key current data is input into the cumulative distribution function, and the preliminary closed-loop success rate is calculated according to the function output value, including: Inputting the first maximum current carrying capacity into the first cumulative distribution sub-function to obtain a first function output value; Inputting the second maximum current carrying capacity into the second cumulative distribution sub-function to obtain a second function output value; Inputting the first current quick-break protection setting value into the third cumulative distribution sub-function to obtain a third function output value; Inputting the second current quick-break protection setting value into the fourth cumulative distribution sub-function to obtain a fourth function output value; The first function output value, the second function output value, the third function output value and the fourth function output value are integrated to calculate a preliminary loop closing success rate.

[0010] According to the active distribution network closed-loop control method provided by the present invention, the closed-loop operation strategy with the optimal safety assessment index value is determined by the following process: According to the preset screening conditions, the candidate closing strategies are screened from all the closing operation strategies; wherein the preset screening conditions include: the initial closing success rate is higher than the preset success rate threshold, and the maximum crossing rate and the average crossing rate are both lower than their corresponding crossing rate thresholds; Performing a weighted operation on the initial loop closing success rate, the maximum limit crossing rate, and the average line crossing rate to calculate a comprehensive evaluation value of each alternative loop closing strategy; The alternative closing strategy with the highest comprehensive evaluation value is used as the closing operation strategy with the best safety evaluation index value.

[0011] According to the active distribution network closed-loop control method provided by the present invention, after the active distribution network is closed-loop controlled according to the target closed-loop operation strategy, the method further includes: Obtain the branch current of each power supply branch in the active distribution network after the ring is closed; Determine whether the branch current of each power supply branch is higher than a preset first current upper limit value, and obtain a first determination result; If the first judgment result is yes, the power supply branch whose branch current is higher than the first current upper limit value is determined as the first target branch, and the output power of the distributed power supply on the first target branch is adjusted to the first power setting value; If the first judgment result is no, then judging whether the branch current of each power supply branch is higher than a preset second current upper limit value, and obtaining a second judgment result; If the second judgment result is yes, the power supply branch whose branch current is higher than the second current upper limit value is determined as the second target branch, and the output power of the distributed power supply on the second target branch is adjusted to the second power setting value; Wherein, the first current upper limit value is higher than the second current upper limit value.

[0012] According to the active distribution network closed-loop control method provided by the present invention, adjusting the output power of the distributed power source on the first target branch to a first power setting value includes: Subtract the branch current of the first target branch from the first current upper limit value to obtain a current over-limit value; If the current over-limit value satisfies a first preset over-limit interval, adjusting the output power of the distributed power source on the first target branch to a first power setting value according to a preset first power adjustment curve; If the current over-limit value satisfies a second preset over-limit interval, adjusting the output power of the distributed power source on the first target branch to a first power setting value according to a preset second power adjustment curve; Among them, the interval upper limit value of the first preset over-limit interval is smaller than the interval upper limit value of the second preset over-limit interval; the average slope of the first power adjustment curve is smaller than the average slope of the second power adjustment curve.

[0013] On the other hand, the present invention also provides an active power distribution network closed-loop control device, comprising: An acquisition module, used to acquire the operation data and load data of the distributed power source in the closed-loop network topology of the active distribution network; A sampling module, used for performing Latin hypercube sampling on the operation data and load data of the distributed power source to obtain photovoltaic semi-invariants and load semi-invariants; A transformation module, used for performing matrix transformation and series expansion on the photovoltaic semi-invariant and the load semi-invariant to obtain a cumulative distribution function and a probability density function of the closed-loop current; An evaluation module, used to obtain key current data of feeders on both sides of the closing point under different closing operation strategies, and input the key current data into the cumulative distribution function and the probability density function to obtain a safety evaluation index value corresponding to each closing operation strategy; The control module is used to take the closing-loop operation strategy with the best safety assessment index value as the target closing-loop operation strategy, and perform closing-loop control on the active distribution network according to the target closing-loop operation strategy.

[0014] On the other hand, the present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, a source distribution network closed-loop control method as described above is implemented.

[0015] The active distribution network closed-loop control method, device and electronic device provided by the present invention obtain photovoltaic semi-invariants and load semi-invariants by Latin hypercube sampling of the operating data and load data of the distributed power source; perform matrix transformation and series expansion on the photovoltaic semi-invariants and the load semi-invariants to obtain the cumulative distribution function and probability density function of the closed-loop current; obtain the key current data of the feeders on both sides of the closed-loop point under different closed-loop operation strategies, and input the key current data into the cumulative distribution function and the probability density function to obtain the safety evaluation index value corresponding to each closed-loop operation strategy; use the closed-loop operation strategy with the optimal safety evaluation index value as the target closed-loop operation strategy, and perform closed-loop control on the active distribution network according to the target closed-loop operation strategy. Since the safety evaluation index value of each closed-loop operation strategy is determined by Latin hypercube sampling and series expansion during the closed-loop process, the active distribution network can be closed-loop controlled according to the closed-loop operation strategy with the optimal safety evaluation index value, thereby improving the safety and reliability of the closed-loop process. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a flow chart of an active distribution network closed-loop control method provided by an embodiment of the present invention; Figure 2 It is the closed-loop network topology corresponding to the active distribution network containing 34 nodes; Figure 3 It is about the closed-loop steady-state current in line 26-28 I a Graph of Figure 4 It is about the closed loop transient current in line 26-28 I am Graph of Figure 5 This is the error comparison diagram between the LHS-GC method and the traditional semi-invariant method; Figure 6 It is a structural schematic diagram of an active power distribution network closed-loop control device provided by an embodiment of the present invention; Figure 7 It is a schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] This embodiment mainly relates to the field of active distribution networks, and can be specifically applied to the closed-loop control link of active distribution networks. With the vigorous development of the national economy, the requirements for power supply reliability in all aspects of social production and life are increasing. As a power supply link directly facing users, the active distribution network usually follows the "closed-loop design, open-loop operation" model. This operation mode is designed to ensure the stability of power supply and the convenience of daily operation and maintenance management. When a distribution line of the active distribution network fails and needs to be handled, or when maintenance work is carried out as planned, the closed-loop power supply operation is an effective response measure. It can achieve load transfer without interrupting power supply, minimizing the impact on user electricity consumption.

[0020] However, the closing and power supply operation of the active distribution network is not without risks. The "first on, then off" method adopted will change the original distribution network structure and power flow distribution. During the closing process, steady-state circulating current and impact current are likely to be generated. These abnormal current conditions may cause the protection device to malfunction and cause the line to overload, which will pose a serious threat to the safe and stable operation of the entire power system.

[0021] Among many distributed power generation technologies, photovoltaic power generation systems, with their significant advantages such as small scale and easy installation, have an increasing proportion in active distribution networks and are gradually playing a pivotal role. The solution provided in this embodiment is mainly for photovoltaic power generation systems. However, the power output of photovoltaic power generation systems is greatly affected by environmental factors such as light intensity and weather conditions, and exhibits strong randomness and volatility, which makes the traditional analysis method based on deterministic parameters and relatively stable working conditions no longer applicable when performing closed-loop related calculations in active distribution networks.

[0022] At the same time, the closing operation of traditional active distribution networks does not fully consider the impact of the randomness and volatility of distributed power output on the closing current, making it difficult to accurately and comprehensively evaluate the safety of closing operations, and it is difficult to effectively deal with the complex conditions faced by closing operations in the current active distribution network environment that contains renewable energy sources such as distributed photovoltaic power sources.

[0023] It can be seen that the traditional active distribution network closed-loop control scheme has problems with insufficient security and reliability.

[0024] In view of the above problems, the embodiments of the present invention provide specific solutions. Figure 1-Figure 7 The invention describes the details of the active power distribution network closed-loop control method, device and electronic equipment provided by the invention.

[0025] Figure 1 It is a flow chart of the active distribution network closed-loop control method provided by an embodiment of the present invention.

[0026] like Figure 1 As shown, the active distribution network closed-loop control method provided by the embodiment of the present invention can be executed by a computer or server with data receiving and data processing capabilities. The method mainly includes the following steps: Step 110: Acquire the operation data and load data of the distributed power sources in the closed-loop network topology of the active distribution network.

[0027] It can be understood that the closed-ring network topology is mainly presented by connecting different distribution lines and distributed power sources in the active distribution network in a topology diagram containing nodes and connections. Figure 2 The closed-ring network topology corresponding to an active power distribution network including 34 nodes is shown as an example.

[0028] In this embodiment, the operation data of the distributed power source includes key information such as the output power of the distributed power source, the node position of the distributed power source in the closed-loop network topology, the node connection relationship, and the line parameters.

[0029] Load data includes information such as load variation patterns and load power values ​​in different time periods.

[0030] Step 120: Perform Latin hypercube sampling on the operation data and load data of the distributed generation to obtain photovoltaic semi-invariants and load semi-invariants.

[0031] In this embodiment, the photovoltaic semi-invariant mainly refers to the cumulative amount corresponding to the operating data of the distributed power source related to the distributed power source, and the load semi-invariant mainly refers to the cumulative amount corresponding to the load data.

[0032] It can be understood that Latin Hypercube Sampling (LHS) is a statistical method for sampling from multidimensional space, which can obtain better coverage of the variable space with a smaller number of samples, thereby performing uncertainty analysis and model evaluation more efficiently.

[0033] Step 130: Perform matrix transformation and series expansion on the photovoltaic semi-invariant and the load semi-invariant to obtain the cumulative distribution function and probability density function of the closed-loop current.

[0034] In this embodiment, by performing matrix transformation on photovoltaic semi-invariants and load semi-invariants, semi-invariants of various orders of the closed-loop current can be obtained, and then the cumulative distribution function and probability density function of the closed-loop current can be fitted by series expansion.

[0035] Step 140: Acquire key current data of feeders on both sides of the closing point under different closing operation strategies, and input the key current data into the cumulative distribution function and the probability density function to obtain the safety assessment index value corresponding to each closing operation strategy.

[0036] It can be understood that in this embodiment, a plurality of closing-loop operation strategies with certain feasibility can be pre-set, and key current data of the closing-loop process under different closing-loop operation strategies can be obtained respectively, and then the safety assessment index values ​​corresponding to the different closing-loop operation strategies can be further determined based on the cumulative distribution function and the probability density function. The safety assessment index values ​​can characterize the safety of the closing-loop operation strategy.

[0037] Step 150: taking the closing operation strategy with the best safety evaluation index value as the target closing operation strategy, and performing closing control on the active distribution network according to the target closing operation strategy.

[0038] This embodiment uses the closing operation strategy with the best safety evaluation index value through screening, and uses it as the target closing operation strategy for closing the active distribution network, thereby ensuring the safety and reliability of the closing link.

[0039] In one embodiment, matrix transformation and series expansion are performed on photovoltaic semi-invariants and load semi-invariants to obtain a cumulative distribution function and a probability density function of the closed-loop current, specifically including: The first step is to perform network flow calculation at the benchmark operating point based on the operating data and load data of the distributed generation to obtain the flow calculation results.

[0040] It is understood that the reference operating point refers to the operating point when the power system is in normal and typical operating conditions. Network flow calculation at the reference operating point is an important basis for power system analysis. Its purpose is to determine the voltage amplitude and phase angle of each node in the power system, as well as the power distribution of each branch. In practical applications, the reference operating point is usually determined based on the system's historical operating data, planning requirements, and typical operating modes.

[0041] In practical applications, network power flow calculation can adopt the currently more mature power flow calculation strategies, such as the Newton-Raphson method, the fast decomposition method and other commonly used power flow calculation strategies, so as to obtain accurate power flow calculation results.

[0042] In this embodiment, the power flow calculation results may include a Jacobian matrix established based on key information such as node voltage amplitude, node voltage phase angle, node injection power, branch active power and reactive power, and branch power loss. and the coefficient matrix .

[0043] In the second step, the photovoltaic semi-invariant and the load semi-invariant are added to calculate the cumulative amount of node injected power.

[0044] In this embodiment, the load semi-invariant and photovoltaic semi-invariant The sum of the node injected power can be obtained , the calculation formula is as follows: (1) The third step is to perform matrix transformation on the accumulated amount of node injected power based on the power flow calculation results, and calculate the semi-invariant of the closed-loop current.

[0045] In this embodiment, the calculation formula of the semi-invariant of the closed-loop current is specifically as follows: (2) in, represents the semi-invariant of the closed-loop current, represents the coefficient matrix, represents the Jacobian matrix, Indicates the accumulated amount of power injected into the node.

[0046] Thus, the semi-invariants of each order of the closed-loop current can be obtained, thus providing effective data basis for the subsequent series expansion link.

[0047] The fourth step is to perform series expansion on the semi-invariant of the closed-loop current and fit the cumulative distribution function and probability density function of the closed-loop current.

[0048] In some embodiments, the series expansion step can be implemented using the Gram-Charlier series, which can be used to represent the probability density function or cumulative distribution function of a random variable as a power series expansion form based on a normal distribution.

[0049] In this embodiment, it is possible to and are the cumulative distribution basis function and probability density basis function of the standard normal distribution, c i are the semi-invariants of the closed-loop current, and the Gram-Charlier series expressions are as follows: (3) (4) in, F ( x ) represents the cumulative distribution function, represents the cumulative distribution basis function of the standard normal distribution, represents the probability density function, and the cumulative distribution function is the integral of the probability density function. represents the probability density basis function of the standard normal distribution, c i Represents the semi-invariants of the closed-loop current, i In the range of [1, k].

[0050] According to the above operation, the cumulative distribution function and probability density function of the closed-loop current can be obtained.

[0051] In one embodiment, the key current data is input into the cumulative distribution function and the probability density function to obtain the safety assessment index value corresponding to each closed-loop operation strategy, specifically including: Firstly, the first key sub-data in the key current data is input into the cumulative distribution function, and the preliminary loop closing success rate is calculated according to the function output value.

[0052] In one embodiment, the first key sub-data specifically include: a first maximum current carrying capacity, a second maximum current carrying capacity, a first current quick-break protection setting value, and a second current quick-break protection setting value of the feeders on both sides of the loop point.

[0053] The cumulative distribution function specifically includes: a first cumulative distribution sub-function corresponding to the first closed-loop steady-state current of the feeders on both sides of the closed-loop point, a second cumulative distribution sub-function corresponding to the second closed-loop steady-state current, a third cumulative distribution sub-function corresponding to the first closed-loop transient current, and a fourth cumulative distribution sub-function corresponding to the second closed-loop transient current.

[0054] In a specific implementation, the first key sub-data in the key current data is input into the cumulative distribution function, and the preliminary loop closing success rate is calculated according to the function output value, which specifically includes: In the first step, the first maximum current carrying capacity is input into the first cumulative distribution sub-function to obtain the first function output value.

[0055] In the second step, the second maximum current carrying capacity is input into the second cumulative distribution sub-function to obtain the output value of the second function.

[0056] The third step is to input the first current quick-break protection setting value into the third cumulative distribution sub-function to obtain the output value of the third function.

[0057] The fourth step is to input the second current quick-break protection setting value into the fourth cumulative distribution sub-function to obtain the fourth function output value.

[0058] The fifth step is to integrate the output values ​​of the first function, the second function, the third function and the fourth function, and calculate the preliminary loop closing success rate.

[0059] In this embodiment, F 1 ( x ) is the first cumulative distribution sub-function corresponding to the first closed-loop steady-state current of the feeders on both sides of the closed-loop point, let F 2 ( x ) is the second cumulative distribution sub-function corresponding to the second closed-loop steady-state current, let F 3 ( x ) is the third cumulative distribution sub-function corresponding to the first closed-loop transient current, let F 4 ( x ) is the fourth cumulative distribution sub-function corresponding to the second closed-loop transient current.

[0060] Take the first maximum current carrying capacity of the feeders on both sides of the closing point as I max.a and the second maximum current carrying capacity is I max.b , the first current quick-break protection setting value is I set.a The second current quick-break protection setting value is I set.b , then the initial closing success rate P It can be expressed as follows: (5) in, P Indicates the initial ring closing success rate, F 1 ( I max.a ) indicates that the first maximum current carrying capacity I max.a Enter the first cumulative distribution subfunction F 1 ( x ) after obtaining the first function output value, F 2 ( I max.b ) indicates that the second maximum current carrying capacity I max.b Enter the second cumulative distribution subfunction F 2 ( x ) and the output value of the second function obtained after F 3 ( I set.a) indicates that the first current quick-break protection setting value I set.a Enter the third cumulative distribution subfunction F 3 ( x ) and the output value of the third function obtained after F 4 ( I set.b ) indicates that the second current quick-break protection setting value I set.b Enter the fourth cumulative distribution subfunction F 4 ( x ) after obtaining the output value of the fourth function.

[0061] This embodiment can calculate the preliminary loop closing success rate of each loop closing operation strategy by multiplying the output values ​​of the four functions. The preliminary loop closing success rate can represent the possibility that the current loop closing operation strategy can successfully close the active distribution network.

[0062] Then, when the initial closing loop success rate is higher than the preset success rate threshold, the second key sub-data in the key current data under each closing loop operation strategy is input into the probability density sub-function to calculate the maximum over-limit rate and average over-line rate of the closing loop current.

[0063] Specifically, the second key sub-data includes the closed-loop current and the preset rated current.

[0064] In this embodiment, the preset success rate threshold can be reasonably set according to actual needs, for example, it can be set to 95%. When the initial loop closing success rate is higher than 95%, it means that the current loop closing operation strategy makes the active distribution network initially close successfully.

[0065] It can be understood that the closed-loop current refers to the current generated in the closed loop when the power system is closed-loop operated due to the difference in parameters such as voltage amplitude, phase and frequency of the power supplies on both sides at the moment of closing the loop. The closed-loop steady-state current refers to the current that continues to exist in the closed-loop circuit after the closing operation is completed and after a period of transition, when the power system enters a stable operating state. The closed-loop transient current refers to the short-term current that appears in the closed-loop circuit from the moment of closing the loop to before the system reaches steady-state operation. In practical applications, the closed-loop current can be obtained after a comprehensive analysis of the closed-loop steady-state current and the closed-loop transient current.

[0066] In this embodiment, the maximum over-limit rate of the closed-loop current and average crossing rate They can be expressed as follows: (6) (7) in, Indicates the maximum over-limit rate of the closed-loop current. Indicates the average over-limit rate of the closed-loop current. I F Indicates the closed loop current, I Lmax Indicates the preset rated current, represents the probability density function.

[0067] In practical applications, the maximum over-limit rate The corresponding crossing rate threshold can be set to 10%, and the average crossing rate The corresponding crossing rate threshold may be 5%.

[0068] Finally, the initial loop closing success rate, maximum limit crossing rate and average line crossing rate are used as the safety evaluation index values ​​corresponding to each loop closing operation strategy.

[0069] In one embodiment, the closed-loop operation strategy with the optimal safety assessment index value can be determined by the following process: In the first step, based on the preset screening conditions, the candidate closing strategies are screened from all closing operation strategies; wherein the preset screening conditions include: the initial closing success rate is higher than the preset success rate threshold, and the maximum crossing rate and the average crossing rate are both lower than their respective corresponding crossing rate thresholds.

[0070] In the second step, weighted operations are performed on the initial loop closing success rate, the maximum limit crossing rate, and the average line crossing rate to calculate the comprehensive evaluation value of each alternative loop closing strategy.

[0071] It should be noted that, in this embodiment, the initial loop closing success rate, the maximum limit crossing rate and the average line crossing rate are all values ​​between 0 and 1. In practical applications, the initial loop closing success rate, the maximum limit crossing rate and the average line crossing rate can be normalized so that the values ​​of the three are all distributed between 0 and 1.

[0072] In this embodiment, the comprehensive evaluation value can be specifically expressed as follows: (8) in, Represents the comprehensive evaluation value, Indicates the initial closing success rate The weight value of Indicates the maximum crossing rate The weight value of Indicates the average crossing rate The weight value of .

[0073] In the third step, the alternative closing strategy with the highest comprehensive evaluation value is used as the closing operation strategy with the best safety evaluation index value.

[0074] In this embodiment, the comprehensive evaluation value can accurately characterize the safety and reliability of each closed-loop operation strategy. The higher the comprehensive evaluation value, the higher the safety and reliability of the closed-loop operation strategy. Therefore, this embodiment will use the alternative closed-loop strategy with the highest comprehensive evaluation value as the closed-loop operation strategy with the best safety evaluation index value.

[0075] In one embodiment, after performing loop closing control on the active distribution network according to the target loop closing operation strategy, the above method may further include: The first step is to obtain the branch current of each power supply branch in the active distribution network after the ring is closed.

[0076] The second step is to determine whether the branch current of each power supply branch is higher than a preset first current upper limit value to obtain a first determination result.

[0077] In the third step, if the first judgment result is yes, the power supply branch whose branch current is higher than the first current upper limit value is determined as the first target branch, and the output power of the distributed power supply on the first target branch is adjusted to the first power setting value.

[0078] The fourth step is to determine whether the branch current of each power supply branch is higher than a preset second current upper limit value if the first determination result is no, and obtain a second determination result.

[0079] Step 5: If the second judgment result is yes, the power supply branch whose branch current is higher than the second current upper limit value is determined as the second target branch, and the output power of the distributed power supply on the second target branch is adjusted to the second power setting value.

[0080] The first current upper limit value is higher than the second current upper limit value.

[0081] It should be noted that, after the closing operation, this embodiment monitors the branch current of each power supply branch in the active distribution network after the closing operation, and controls the branch current by means of hierarchical control. Specifically, when the branch current exceeds the first current upper limit value, it means that the branch current is already in the first-level current interval, and the safety hazard of the active distribution network is relatively high. In this regard, this embodiment adjusts the output power of the distributed power source on the first target branch to the first power setting value, and reduces the branch current by adjusting the output power of the distributed power source to ensure the safe operation of the active distribution network.

[0082] Similarly, when the branch current exceeds the second current upper limit, it means that the branch current is in the secondary current range. At this time, the active distribution network also has certain safety hazards. At this time, the output power of the distributed power supply on the second target branch will be adjusted to the second power setting value. The branch current can be further reduced by adjusting the output power of the distributed power supply.

[0083] In practical applications, the first power setting value is higher than the second power setting value to avoid excessive adjustment of the output power of the distributed power source to affect the stable operation of the active distribution network.

[0084] In a specific implementation, adjusting the output power of the distributed power source on the first target branch to a first power setting value specifically includes: In the first step, a branch current of the first target branch is subtracted from a first current upper limit value to obtain a current overlimit value.

[0085] In the second step, if the current over-limit value satisfies a first preset over-limit interval, the output power of the distributed power source on the first target branch is adjusted to a first power setting value according to a preset first power adjustment curve.

[0086] In the third step, if the current over-limit value satisfies the second preset over-limit interval, the output power of the distributed power source on the first target branch is adjusted to the first power setting value according to the preset second power adjustment curve.

[0087] Among them, the interval upper limit value of the first preset over-limit interval is smaller than the interval upper limit value of the second preset over-limit interval; the average slope of the first power adjustment curve is smaller than the average slope of the second power adjustment curve.

[0088] In practical applications, the average slope can be determined by the following process: First, extract multiple key data points from the first power adjustment curve or the second power adjustment curve, and determine the slope value corresponding to each key data point; Then, the slope values ​​of all key data points are averaged to calculate the average slope.

[0089] It can be understood that this embodiment can adopt a reasonable adjustment scheme for the output power of the distributed power source in a targeted manner according to the over-limit situation of the branch current. During the adjustment process, if the current over-limit value satisfies the first preset over-limit interval, the output power of the distributed power source is adjusted according to the first power adjustment curve with a relatively gentle change; if the current over-limit value satisfies the second preset over-limit interval, the output power of the distributed power source is adjusted according to the second power adjustment curve with a relatively steep change, thereby avoiding the output power of the distributed power source from fluctuating violently in a short period of time and affecting the operating stability of the active distribution network.

[0090] Similarly, in the process of adjusting the output power of the distributed power source on the second target branch to the second power setting value, a solution consistent with the principle of the output power adjustment solution of the distributed power source on the first target branch can be adopted.

[0091] The beneficial effects that can be produced by the active distribution network closed-loop control method provided in this embodiment are described in detail below through a specific example.

[0092] by Figure 2 Taking the active power distribution network with 34 nodes as an example, a photovoltaic power source is configured at the 34th node, and the shape parameter is adopted. is 0.679, The Beta distribution of 1.778 is used to model the photovoltaic power source, and the maximum light intensity is 1.134kW / m 2 Select the ring branch with 28-34 nodes and take the benchmark capacity S B For 1MVA, the reference voltage U B It is 24.9kV.

[0093] For the above configuration, the MC (Monte Carlo) method, the traditional semi-invariant method and the improved active distribution network closed-loop control method (LHS-GC method for short) provided in this embodiment are respectively used to perform closed-loop operation. The sampling scale of the MC method is 10,000. It is believed that the MC method result under this sampling scale is accurate. The LHS sampling scale is 500. Among them, the closed-loop steady-state current in line 26-28 I a The curve diagram can be seen in Figure 3 As shown, the horizontal axis represents the closed-loop steady-state current in line 26-28 I a The vertical axis represents the cumulative distribution probability of the closed-loop steady-state current corresponding to line 26-28 F 1 , Figure 3 It can be seen that in the calculation results of the closed-loop steady-state current, the LHS-GC method has higher accuracy than the traditional semi-invariant method, and is more consistent with the cumulative probability distribution curve obtained by the MC method.

[0094] Figure 4 The closed-loop transient current in line 26-28 under the above three closed-loop methods is shown. I am A curve diagram of the circuit 26-28, wherein the horizontal axis represents the closed-loop transient current in the circuit 26-28 I am The vertical axis represents the cumulative distribution probability of the transient current of the line 26-28 corresponding to the closed loop F 3 , Figure 4 It can be seen that in the calculation results of closed-loop transient current, the LHS-GC method has higher accuracy than the traditional semi-invariant method, and is more consistent with the cumulative probability distribution curve obtained by the MC method.

[0095] Figure 5The error comparison between the LHS-GC method and the traditional semi-invariant method is shown, where the horizontal axis represents the closed-loop steady-state current of the feeders on both sides of the closed-loop point. I a and I b And the closing transient current of the feeders on both sides of the closing point I am and I bm , the ordinate represents the error percentage, Figure 5 It can be seen that the current error corresponding to the LHS-GC method is smaller when the cumulative distribution probability is 90%, and is less than 2%. The results show that the LHS-GC method has a better effect in fitting the cumulative distribution function of the feeder loop current and has a higher accuracy.

[0096] Based on the same general inventive concept, the present invention also protects an active distribution network closed-loop control device. The active distribution network closed-loop control device provided by the present invention is described below. The active distribution network closed-loop control device described below and the active distribution network closed-loop control method described above can be referenced to each other.

[0097] Figure 6 It is a structural schematic diagram of an active distribution network closed-loop control device provided in an embodiment of the present invention.

[0098] like Figure 6 As shown, the active power distribution network closed-loop control device provided by the embodiment of the present invention specifically includes: An acquisition module 210 is used to acquire operation data and load data of distributed power sources in a closed-loop network topology of an active distribution network; The sampling module 220 is used to perform Latin hypercube sampling on the operation data and load data of the distributed power source to obtain photovoltaic semi-invariants and load semi-invariants; A transformation module 230 is used to perform matrix transformation and series expansion on the photovoltaic semi-invariant and the load semi-invariant to obtain a cumulative distribution function and a probability density function of the closed-loop current; Evaluation module 240, used to obtain key current data of feeders on both sides of the closing point under different closing operation strategies, and input the key current data into cumulative distribution function and probability density function to obtain the safety evaluation index value corresponding to each closing operation strategy; The control module 250 is used to take the closing operation strategy with the best safety evaluation index value as the target closing operation strategy, and perform closing control on the active distribution network according to the target closing operation strategy.

[0099] Regarding the device in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated again here.

[0100] Figure 7 It is a schematic diagram of the structure of an electronic device provided by an embodiment of the present invention.

[0101] like Figure 7 As shown, the electronic device may include: a processor 310, a communication interface 320, a memory 330 and a communication bus 340, wherein the processor 310, the communication interface 320 and the memory 330 communicate with each other through the communication bus 340. The processor 310 may call the logic instructions in the memory 330 to execute the active power distribution network closed-loop control method provided in the above-mentioned embodiments.

[0102] In addition, the logic instructions in the above-mentioned memory 330 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0103] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the active distribution network closed-loop control method provided in the above embodiments.

[0104] On the other hand, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which is implemented when the computer program is executed by a processor to execute the active distribution network closed-loop control method provided by the above embodiments.

[0105] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0106] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A closed-loop control method for an active distribution network, characterized in that: include: Obtaining the operating data and load data of distributed power sources in the closed-ring network topology of the active distribution network; Performing Latin hypercube sampling on the operation data and load data of the distributed power source to obtain photovoltaic semi-invariants and load semi-invariants; Performing matrix transformation and series expansion on the photovoltaic semi-invariant and the load semi-invariant to obtain a cumulative distribution function and a probability density function of the closed-loop current; Acquire key current data of feeders on both sides of the closing point under different closing operation strategies, and input the key current data into the cumulative distribution function and the probability density function to obtain the safety assessment index value corresponding to each closing operation strategy; The closed-loop operation strategy with the best safety evaluation index value is used as the target closed-loop operation strategy, and the active distribution network is closed-loop controlled according to the target closed-loop operation strategy.

2. The active distribution network closed-loop control method according to claim 1, characterized in that: The photovoltaic semi-invariant and the load semi-invariant are subjected to matrix transformation and series expansion to obtain a cumulative distribution function and a probability density function of the closed-loop current, including: Based on the operation data and load data of the distributed power source, a network power flow calculation is performed at a reference operation point to obtain a power flow calculation result; Adding the photovoltaic semi-invariant and the load semi-invariant to calculate the node injection power accumulation; Based on the power flow calculation result, matrix transformation is performed on the accumulated amount of power injected into the node to calculate the semi-invariant of the closed-loop current; The semi-invariant of the closed-loop current is expanded in series, and the cumulative distribution function and probability density function of the closed-loop current are obtained by fitting.

3. The active distribution network closed-loop control method according to claim 1, characterized in that: The key current data is input into the cumulative distribution function and the probability density function to obtain the safety assessment index value corresponding to each closed-loop operation strategy, including: Inputting the first key sub-data in the key current data into the cumulative distribution function, and calculating the preliminary loop closing success rate according to the function output value; When the initial closing loop success rate is higher than the preset success rate threshold, the second key sub-data in the key current data under each closing loop operation strategy is input into the probability density sub-function to calculate the maximum over-limit rate and average over-line rate of the closing loop current; The initial loop closing success rate, the maximum limit crossing rate and the average line crossing rate are used as safety evaluation index values ​​corresponding to each loop closing operation strategy.

4. The active distribution network closed-loop control method according to claim 3, characterized in that: The first key sub-data include: the first maximum current carrying capacity, the second maximum current carrying capacity, the first current quick-break protection setting value and the second current quick-break protection setting value of the feeders on both sides of the loop closing point; The second key sub-data includes: closed-loop current and preset rated current; The cumulative distribution function includes: a first cumulative distribution sub-function corresponding to the first closed-loop steady-state current of the feeders on both sides of the closed-loop point, a second cumulative distribution sub-function corresponding to the second closed-loop steady-state current, a third cumulative distribution sub-function corresponding to the first closed-loop transient current, and a fourth cumulative distribution sub-function corresponding to the second closed-loop transient current.

5. The active distribution network closed-loop control method according to claim 4, characterized in that: Inputting the first key sub-data in the key current data into the cumulative distribution function, and calculating the preliminary loop closing success rate according to the function output value, including: Inputting the first maximum current carrying capacity into the first cumulative distribution sub-function to obtain a first function output value; Inputting the second maximum current carrying capacity into the second cumulative distribution sub-function to obtain a second function output value; Inputting the first current quick-break protection setting value into the third cumulative distribution sub-function to obtain a third function output value; Inputting the second current quick-break protection setting value into the fourth cumulative distribution sub-function to obtain a fourth function output value; The first function output value, the second function output value, the third function output value and the fourth function output value are integrated to calculate a preliminary loop closing success rate.

6. The active distribution network closed-loop control method according to claim 3, characterized in that: The closed-loop operation strategy with the best safety assessment index value is determined by the following process: According to the preset screening conditions, the candidate closing strategies are screened from all the closing operation strategies; wherein the preset screening conditions include: the initial closing success rate is higher than the preset success rate threshold, and the maximum crossing rate and the average crossing rate are both lower than their corresponding crossing rate thresholds; Performing a weighted operation on the initial loop closing success rate, the maximum limit crossing rate, and the average line crossing rate to calculate a comprehensive evaluation value of each alternative loop closing strategy; The alternative closing strategy with the highest comprehensive evaluation value is used as the closing operation strategy with the best safety evaluation index value.

7. The closed-loop control method of active power distribution network according to claim 1, characterized in that: After performing loop closing control on the active distribution network according to the target loop closing operation strategy, the method further includes: Obtain the branch current of each power supply branch in the active distribution network after the ring is closed; Determine whether the branch current of each power supply branch is higher than a preset first current upper limit value, and obtain a first determination result; If the first judgment result is yes, the power supply branch whose branch current is higher than the first current upper limit value is determined as the first target branch, and the output power of the distributed power supply on the first target branch is adjusted to the first power setting value; If the first judgment result is no, then judging whether the branch current of each power supply branch is higher than a preset second current upper limit value, and obtaining a second judgment result; If the second judgment result is yes, the power supply branch whose branch current is higher than the second current upper limit value is determined as the second target branch, and the output power of the distributed power supply on the second target branch is adjusted to the second power setting value; Wherein, the first current upper limit value is higher than the second current upper limit value.

8. The closed-loop control method of active power distribution network according to claim 7, characterized in that: Adjusting the output power of the distributed power source on the first target branch to a first power setting value includes: Subtract the branch current of the first target branch from the first current upper limit value to obtain a current over-limit value; If the current over-limit value satisfies a first preset over-limit interval, adjusting the output power of the distributed power source on the first target branch to a first power setting value according to a preset first power adjustment curve; If the current over-limit value satisfies a second preset over-limit interval, adjusting the output power of the distributed power source on the first target branch to a first power setting value according to a preset second power adjustment curve; Among them, the interval upper limit value of the first preset over-limit interval is smaller than the interval upper limit value of the second preset over-limit interval; the average slope of the first power adjustment curve is smaller than the average slope of the second power adjustment curve.

9. An active distribution network closed-loop control device, characterized in that: include: An acquisition module, used to acquire the operation data and load data of the distributed power source in the closed-loop network topology of the active distribution network; A sampling module, used for performing Latin hypercube sampling on the operation data and load data of the distributed power source to obtain photovoltaic semi-invariants and load semi-invariants; A transformation module, used for performing matrix transformation and series expansion on the photovoltaic semi-invariant and the load semi-invariant to obtain a cumulative distribution function and a probability density function of the closed-loop current; An evaluation module, used to obtain key current data of feeders on both sides of the closing point under different closing operation strategies, and input the key current data into the cumulative distribution function and the probability density function to obtain a safety evaluation index value corresponding to each closing operation strategy; The control module is used to take the closing-loop operation strategy with the best safety evaluation index value as the target closing-loop operation strategy, and perform closing-loop control on the active distribution network according to the target closing-loop operation strategy.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the program, the active power distribution network closed-loop control method as described in any one of claims 1 to 8 is implemented.

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