Multi-type net rack comparison method and device

Abstract

The invention is suitable for the technical field of electric power, and provides a multi-type grid comparison method and device, and the method comprises the steps: obtaining an operation mode demand of a target region and an existing grid structure; determining power supply capabilities of different types of typical grid structures according to operation mode requirements; according to an existing grid structure, the construction cost of different types of typical grid structures is determined; determining unit power supply load cost of different types of typical grid structures according to the power supply capability and the construction cost; and based on the unit power supply load cost of the different types of typical grid structures and the pre-calculated reliability of the different types of typical grid structures, determining the comprehensive score of the different types of typical grid structures, and determining the optimal type of typical grid structure according to the comprehensive score. Reasonable construction and efficient investment of the power distribution network can be realized.

Description

Technical Field

[0001] The present invention belongs to the field of electric power technology, and in particular relates to a multi-type grid comparison method and device. Background Art

[0002] As the scale of distribution network construction increases year by year, the power supply capacity and reliability levels are constantly improved, and differentiated distribution network development strategies have gradually been formed based on the differences in economic and social development levels and electricity demand in different regions.

[0003] Researching a highly reliable medium-voltage distribution network that is adapted to the characteristics of future urban development, combining the current characteristics of the medium-voltage distribution network grid structure, fully considering the future urban power grid planning layout, and selecting a suitable grid structure can reduce the construction and operation costs of the distribution network and improve the reliability of power supply. However, there is no research in this area in the relevant technology. For example, patent CN201911132700.5 discloses a method for formulating a target grid of a medium-voltage distribution network based on main transformer N-1, which only makes the grid structure reasonable in specific construction, and does not conduct a comparative analysis of grid types. Therefore, studying the most suitable grid structure selection method for different regions is of great significance to the reasonable construction and efficient investment of distribution networks. Summary of the invention

[0004] In view of this, an embodiment of the present invention provides a multi-type grid comparison method and device to study the most suitable grid structure in different regions and realize the reasonable construction and efficient investment of the distribution network.

[0005] A first aspect of an embodiment of the present invention provides a multi-type grid comparison method, comprising:

[0006] Obtain the operation mode requirements and existing grid structure of the target area;

[0007] Determine the power supply capacity of different types of typical grid structures according to the operation mode requirements;

[0008] Based on the existing grid structures, determine the construction costs of different types of typical grid structures;

[0009] Determine the unit power supply load cost of different types of typical grid structures based on power supply capacity and construction cost;

[0010] Based on the unit power supply load costs of different types of typical grid structures and the pre-calculated reliabilities of different types of typical grid structures, comprehensive scores of different types of typical grid structures are determined, and based on the comprehensive scores, the optimal type of typical grid structure is determined.

[0011] In combination with the first aspect, in a possible implementation of the first aspect, determining power supply capabilities of different types of typical grid structures according to operation mode requirements includes:

[0012] According to the operation mode requirements, calculate the maximum operating load rate of the trunk line of each type of typical grid structure;

[0013] The power supply capacity of each type of typical grid structure is determined based on the trunk line scale and the maximum operating load rate of the trunk line of each type of typical grid structure.

[0014] In conjunction with the first aspect, in a possible implementation of the first aspect, the construction costs of different types of typical grid structures are determined based on existing grid structures, including:

[0015] Consistently set equipment parameters for each type of typical grid structure;

[0016] Determine the way to upgrade the existing grid structure to different types of typical grid structures, and determine the construction cost of different types of typical grid structures based on equipment parameters and methods.

[0017] In combination with the first aspect, in a possible implementation of the first aspect, the reliability of a typical grid structure is calculated by a failure mode and effects analysis method.

[0018] In combination with the first aspect, in a possible implementation of the first aspect, calculating the reliability of a typical grid structure by using a failure mode and effect analysis method includes:

[0019] Calculate the failure outage rate and failure outage time of each load point after each facility fails;

[0020] For each load point, the expected value of the fault outage time of the load point is determined according to the fault outage rate and fault outage time corresponding to all the facilities that cause the fault of the load point;

[0021] According to the expected value of fault outage time at each load point and the number of users at each load point, the expected value of the average power supply reliability rate of the typical grid structure is calculated as the reliability index.

[0022] In combination with the first aspect, in a possible implementation of the first aspect, according to the expected value of the fault outage time of each load point and the number of users at each load point, the average power supply of the system of the typical grid structure can be calculated considering the expected value as a reliability indicator, including:

[0023] according to Calculate the expected average power outage time of the typical grid structure; where S1 is the expected average power outage time of the system, u i is the expected value of the power outage time of the i-th load point, Ki is the number of users at the ith load point, K is the total number of users in the system;

[0024] according to Calculate the expected value of the average power supply reliability rate of the system for a typical grid structure; where S2 is the expected value of the average power supply reliability rate of the system, and T is the total hours per unit year.

[0025] In combination with the first aspect, in a possible implementation manner of the first aspect, the reliability of the typical grid structure is calculated by establishing a simulation model of the typical grid structure.

[0026] In combination with the first aspect, in a possible implementation of the first aspect, based on the unit power supply load costs of different types of typical grid structures and the pre-calculated reliabilities of different types of typical grid structures, determining comprehensive scores of different types of typical grid structures, and determining the optimal type of typical grid structure according to the comprehensive scores, including:

[0027] Determine the first score of each typical grid structure according to the unit power supply load cost; wherein the first score is positively correlated with the unit power supply load cost;

[0028] Determine the second score of each typical grid structure according to the reliability; wherein the second score is negatively correlated with the reliability;

[0029] Perform weighted fusion on the first score and the second score of each typical grid structure to obtain a comprehensive score of each typical grid structure;

[0030] The typical grid structure with the lowest comprehensive score is determined as the optimal type of typical grid structure.

[0031] In combination with the first aspect, in a possible implementation of the first aspect, the weight values ​​corresponding to the first score and the second score are determined based on the needs of the target area, combined with the Delphi expert survey method and the fuzzy analysis method, and the entropy theory is used to quantitatively analyze and determine the weight ranking.

[0032] A second aspect of the embodiment of the invention provides a multi-type grid comparison device, comprising:

[0033] An acquisition module is used to obtain the operation mode requirements and existing grid structure of the target area;

[0034] The first calculation module is used to determine the power supply capacity of different types of typical grid structures according to the operation mode requirements;

[0035] The second calculation module is used to determine the construction cost of different types of typical grid structures based on the existing grid structures;

[0036] The third calculation module is used to determine the unit power supply load cost of different types of typical grid structures according to power supply capacity and construction cost;

[0037] The determination module is used to determine the comprehensive scores of different types of typical grid structures based on the unit power supply load costs of different types of typical grid structures and the pre-calculated reliabilities of different types of typical grid structures, and determine the optimal type of typical grid structure based on the comprehensive scores.

[0038] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0039] The embodiment of the present invention determines the power supply capacity of different types of typical grid structures according to the operation mode requirements of the target area, determines the construction cost of different types of typical grid structures according to the existing grid structure, and further determines the unit power supply load cost of different types of typical grid structures according to the power supply capacity and construction cost, so as to achieve cost comparison of different types of typical grid structures for the target area. Furthermore, the comprehensive score of the typical grid structure is determined in combination with the reliability of different types of typical grid structures, so as to determine a more suitable grid solution and achieve reasonable construction and efficient investment of the distribution network. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0041] Figure 1 It is a schematic diagram of the implementation process of the multi-type grid comparison method provided by an embodiment of the present invention;

[0042] Figure 2 It is a schematic diagram of the structure of a multi-type grid comparison device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0044] In order to illustrate the technical solution of the present invention, a specific embodiment is provided below for illustration.

[0045] With the acceleration of urbanization, the overall urban electricity load shows a trend of continuous growth. According to statistical data, urban electricity consumption has been rising year by year in recent years, and the growth rate has gradually accelerated. In the future development, urban electricity load will continue to grow. In addition, large-scale distributed power sources, charging piles and other user-side equipment will be connected to the distribution network. Especially with the accelerated construction of new power systems, the distribution network will show the characteristics of high proportion of distributed power sources, pulse loads, and power electronic equipment in form, and mathematically show the characteristics of uncertainty in power supply, load, and spatiotemporal state. At the system level, due to the access of a large number of distributed resources, the distribution network will evolve from a single power distribution network to a multi-energy complementary configuration platform, showing the characteristics of complex network structure, complex operating conditions, and complex operating environment. Under the dual background of energy transformation and digital transformation, it is necessary to vigorously promote the construction of modern smart distribution networks. Modern smart distribution networks can be regarded as the distribution network form of new power systems. Compared with traditional power grids, modern smart distribution networks have the characteristics of informatization, automation, and interactivity, and through the deep integration of advanced information and other technologies, they realize the highly integrated integration of "power flow, information flow, and business flow". Against the backdrop of energy transformation, the construction of modern smart distribution networks can not only improve the utilization rate of existing power grid assets and reduce grid congestion and bottlenecks, but also improve asset management on the power generation side and user terminals, and enhance the operational efficiency of the entire power assets; in terms of technological innovation, modern smart distribution networks focus on breakthroughs in technologies such as source-load prediction and tracking, AC / DC hybrid networking, virtual power plant dispatching, charging and discharging power regulation, information security, and smart energy simulation; in terms of resource coordination, modern smart distribution networks focus on achieving transparent perception of power supply and demand systems, efficient business integration, intelligent operation and management, and platform-based resource allocation, to build an ecological system for collaborative interaction among multiple supply and demand parties; in terms of operating models, modern smart distribution networks explore the construction of an operating system with diversified market entities, diverse transaction varieties, and rich service types, to promote changes in production methods and business models.

[0046] At present, different regions have proposed different types of high-reliability typical grid structure solutions based on their own advantages and characteristics, such as "double petal" power grid, "diamond" power grid, "snowflake" power grid, "star" power grid, etc. There is still a lot of potential for the development of high-reliability urban grid structures.

[0047] The embodiment of the present invention proposes a multi-type grid comparison method to help different regions select the most suitable grid structure.

[0048] See also Figure 1 As shown, the method includes:

[0049] Step S101, obtaining the operation mode requirements and existing grid structure of the target area.

[0050] In this embodiment, the operation mode requirement may be to require grid N-1 or N-2, etc., which will change the maximum power supply capacity of the grid; the existing grid structure determines the construction scale required to upgrade the grid.

[0051] Step S102, determining the power supply capacity of different types of typical grid structures according to the operation mode requirements.

[0052] As a possible implementation method, the power supply capacity of different types of typical grid structures is determined according to the operation mode requirements, including:

[0053] According to the operation mode requirements, calculate the maximum operating load rate of the trunk line of each type of typical grid structure;

[0054] The power supply capacity of each type of typical grid structure is determined based on the trunk line scale and the maximum operating load rate of the trunk line of each type of typical grid structure.

[0055] In this embodiment, taking grid N-1 as an example, the main line operating load rate of each type of grid under line N-1 and power supply N-1 can be analyzed under the premise of ensuring that the specifications of each type of grid cable line and overhead line are consistent, and the power supply capacity of each type of grid is calculated according to the maximum operating load rate of the main line of each type of grid and the scale of the main line.

[0056] Step S103, determining the construction costs of different types of typical grid structures based on existing grid structures.

[0057] This embodiment first presents the overall scale of the grid by analyzing and comparing the number of substations, switch stations, and 10kV lines used in various types of grids and their connection methods, providing basic data for subsequent grid structure construction cost calculation and grid structure unit power supply load cost calculation, and can analyze the convenience of its transformation through the grid structure.

[0058] As a possible implementation method, the construction costs of different types of typical grid structures are determined based on the existing grid structures, including:

[0059] Consistently set equipment parameters for each type of typical grid structure;

[0060] Determine the way to upgrade the existing grid structure to different types of typical grid structures, and determine the construction cost of different types of typical grid structures based on equipment parameters and methods.

[0061] Before conducting cost analysis and comparison of each grid structure, the equipment specifications, model parameters, and cost parameters are first set to ensure horizontal comparability. Furthermore, by listing and comparing the grid upgrade methods, the grid upgrade process can be obtained, providing technical support for subsequent grid structure transformation. By statistically analyzing the scale of various equipment for grid upgrades and performing cost calculations, the construction cost of each grid is obtained.

[0062] Step S104, determining the unit power supply load cost of different types of typical grid structures according to the power supply capacity and construction cost.

[0063] In this embodiment, the construction cost is divided by the power supply capacity to obtain the unit power supply load cost.

[0064] Step S105, based on the unit power supply load costs of different types of typical grid structures and the pre-calculated reliabilities of different types of typical grid structures, determine the comprehensive scores of different types of typical grid structures, and determine the optimal type of typical grid structure based on the comprehensive scores.

[0065] In this embodiment, by analyzing the secondary configuration specifications and scale of each grid main network and secondary network, the protection and automation protection level of each grid main network and secondary network can be obtained, providing reference data for the comparison of power supply reliability. Further, the power supply reliability of the grid is calculated according to the failure mode and effect analysis method, or the power supply reliability data of each grid is calculated using a simulation model. The grid is evaluated in combination with the reliability of the grid and the unit power supply load cost, so as to select the grid structure that best suits the target area.

[0066] The embodiment of the present invention determines the power supply capacity of different types of typical grid structures according to the operation mode requirements of the target area, determines the construction cost of different types of typical grid structures according to the existing grid structure, and further determines the unit power supply load cost of different types of typical grid structures according to the power supply capacity and construction cost, so as to achieve cost comparison of different types of typical grid structures for the target area. Furthermore, the comprehensive score of the typical grid structure is determined in combination with the reliability of different types of typical grid structures, so as to determine a more suitable grid solution and achieve reasonable construction and efficient investment of the distribution network.

[0067] In one embodiment, the failure mode and effect analysis method is used to calculate the reliability of a typical grid structure, and the method is as follows:

[0068] The reliability of typical grid structures is calculated by failure mode and effects analysis, including:

[0069] Calculate the failure outage rate and failure outage time of each load point after each facility fails;

[0070] For each load point, the expected value of the fault outage time of the load point is determined according to the fault outage rate and fault outage time corresponding to all the facilities that cause the fault of the load point;

[0071] According to the expected value of fault outage time at each load point and the number of users at each load point, the expected value of the average power supply reliability rate of the typical grid structure is calculated as the reliability index.

[0072] Among them, according to the expected value of the fault outage time of each load point and the number of users at each load point, the expected value can be considered as the reliability index for calculating the average power supply of the system of the typical grid structure, including:

[0073] according to Calculate the expected average power outage time of the typical grid structure; where S1 is the expected average power outage time of the system, u i is the expected value of the power outage time of the i-th load point, K i is the number of users at the ith load point, K is the total number of users in the system;

[0074] according to Calculate the expected value of the average power supply reliability rate of the system for a typical grid structure; where S2 is the expected value of the average power supply reliability rate of the system, and T is the total hours per unit year.

[0075] Failure mode and effects analysis is applicable to open-loop and closed-loop distribution networks. Failure mode and effects analysis calculates load point and system reliability indicators by analyzing all possible failure events and their consequences on the system.

[0076] First, enumerate the failures of individual facilities, take into account the process of circuit breaker tripping, fault isolation, and power restoration after the failure of the facility, determine the impact of the failure on the power outage of each load point, and further determine the failure power outage rate and failure power outage time of each load point. Then, list the failure power outage rate and failure power outage time of each load point after all facilities fail individually to form a failure mode consequence analysis table. The set of facilities that will cause power outage at the load point LP after the failure is N, and the failure power outage rate and failure power outage time of the i-th facility in the facility set are λ respectively. i and r i The expected value of the fault outage time of this load point is u i =∑ i∈N (λ i × i). Calculate the expected value of the fault outage time for each load point in turn, and on this basis, consider the number of users at the load point and the total number of users in the system, calculate the expected value of the average power outage time of the system, and obtain the reliability index. Among them, the fault outage rate and the expected value of the fault outage time of the load point depend on the failure rate parameters of all upstream equipment from the fault point to the load point, the fault outage time, the switch action time, and the pre-arranged power outage time. Such parameters can be obtained based on the statistical probability in the local system. (Line equipment fault outage rate = line length × line fault outage rate / 100, switch equipment fault outage rate = average failure rate per 100 switch devices).

[0077] In one embodiment, based on the unit power supply load costs of different types of typical grid structures and the pre-calculated reliabilities of different types of typical grid structures, comprehensive scores of different types of typical grid structures are determined, and according to the comprehensive scores, the optimal type of typical grid structure is determined, including:

[0078] The first score of each typical grid structure is determined according to the unit power supply load cost; wherein the first score is positively correlated with the unit power supply load cost

[0079] Determine the second score of each typical grid structure according to the reliability; wherein the second score is negatively correlated with the reliability;

[0080] Perform weighted fusion on the first score and the second score of each typical grid structure to obtain a comprehensive score of each typical grid structure;

[0081] The typical grid structure with the lowest comprehensive score is determined as the optimal type of typical grid structure.

[0082] In this embodiment, different 10kV grid schemes can be ranked based on the calculation results. First, the power supply reliability is ranked from high to low. The higher the reliability, the higher the ranking and the lower the score. Then, the unit power supply load cost is ranked from low to high. The lower the unit power supply load cost, the higher the ranking and the lower the score. The reliability weight can be scored as 0.6, and the unit power supply load cost weight can be scored as 0.4. The lower the combined score of the two, the better the overall effect of the grid.

[0083] Here, the weight values ​​corresponding to the first score and the second score are determined based on the needs of the target area, combined with the Delphi expert survey method and the fuzzy analysis method, and the entropy theory is used to quantitatively analyze and determine the weight ranking.

[0084] Information entropy can reflect both the subjective will of decision makers for evaluation indicators and the objective authenticity of indicator weight coefficients. Entropy represents the measure of the degree of energy exhaustion in a material system. Information entropy reflects the degree of information disorder and has a certain objectivity. When the information entropy is smaller and the entropy weight is larger, the information utility value provided by the information to the decision maker will be greater.

[0085] This embodiment is based on the improved entropy weight method of information entropy theory, combines the Delphi expert survey method for collecting expert opinions with the fuzzy analysis method, and uses the entropy theory to perform quantitative analysis on weight ranking, which can eliminate the uncertainty problem in the allocation of indicator weights.

[0086] Experts independently give their own qualitative judgments on the evaluation indicators based on their own knowledge and experience. The decision matrix X for the comprehensive decision problem considering m experts and n indicators is:

[0087]

[0088] In the formula, x ij represents the evaluation of the i-th expert on the j-th indicator. Then, the entropy E about the j-th indicator is j for:

[0089]

[0090] The smaller the entropy value, the higher the accuracy of the evaluation value and the higher the credibility. k is a random number.

[0091] Therefore, the information bias is:

[0092] θ j =1-E j

[0093] If the decision maker has no preference between indicators, according to uncertainty theory, it can be considered that n indicators have the same preference, and the weight formula is:

[0094]

[0095] If the decision maker has a preference for the indicator set, he needs to give the indicator set his own subjective cognition, and the weight is modified as follows:

[0096]

[0097] Therefore, after giving the qualitative judgment of the "ranking" opinions of different indicators on the importance of the evaluation indicator set, the information entropy theory is used to measure the uncertainty generated by the "expert ranking". Combined with the fuzzy analysis method, the entropy function (membership function) on the fuzzy set is established, and the membership function M of the ranking decision matrix is ​​obtained as follows:

[0098] M(x)=-λρ n(x)lnρ n (x)

[0099] in:

[0100]

[0101] In the formula, x is the ranking number of each indicator by the expert, x∈the natural number set {1,2,…,n}, x=1 means that the expert thinks this indicator is the most important; if the maximum sequence number is defined as r, d is the conversion parameter, then d=r+2. The membership degree u(x) corresponding to the ranking number x is:

[0102]

[0103] In order to obtain a more scientific decision, the fuzzy matrix U is constructed by multiple experts. If it is assumed that the importance of each expert is consistent, then the average recognition of m experts on indicator j is:

[0104]

[0105] The comprehensive awareness of all experts on the i-th indicator is:

[0106] C j =u j (1-z j )

[0107] In the formula, z j It represents the uncertainty of the expert’s subjective understanding and can be expressed as:

[0108]

[0109] The comprehensive cognition C j Normalize and get the weight w of each indicator j for:

[0110]

[0111] According to this method, the indicators such as power supply reliability and unit power supply load cost are weighted and analyzed to obtain the grid suitability ranking.

[0112] This embodiment adopts a comparison method of multiple types of 10kV grid schemes, which can obtain the ranking of various types of grids, lay a good foundation for subsequent work, and comprehensively improve work efficiency. At the same time, the working mode is clear, efficient, and replicated, which has a wide range of promotion significance. It has high applicability in various regions and can effectively assist in the comparison of 10kV grid schemes. The problem of adjusting the 10kV grid structure is often accompanied by large-scale power grid upgrades and construction, and these investments and constructions are generally less economical. The method of this embodiment can be used to make more accurate and efficient investments, which not only improves the utilization efficiency of power grid equipment, but also avoids inefficient investments.

[0113] To facilitate understanding of this solution, an example is given below:

[0114] For target area A, six typical grid structures were selected: the two "double petal" structures are both medium-voltage line ring operation connection methods, the "star" and "diamond" structures are both primary and secondary layered connection methods with the switch station as the core, and the "snowflake" and "four-corner six connection" are both strong connection methods between power sources.

[0115] (1) The comparison of specific networking modes is shown in Table 1.

[0116] Table 1 Networking modes of typical grid structures

[0117]

[0118] (2) Maximum allowable load of the trunk of each grid structure under different conditions

[0119] This calculation uses the YJV22-3*400 cable trunk, with a maximum allowable conductor current of 692A and a maximum allowable conductor load of 11.39MW; the JKLGYJ-240 overhead trunk is used, with a maximum allowable conductor current of 513A and a maximum allowable conductor load of 8.44MW.

[0120] In the case where line N-1 is the highest upper limit, the load rate and power supply capacity of each grid structure (line N-1) are shown in Table 2:

[0121] Table 2 Load rate and power supply capacity of each typical grid structure (line N-1)

[0122]

[0123] Under the condition that power source N-1 (10kV busbar N-1) is the highest upper limit (without considering the substation bus coupling), the operation mode and load rate of each grid structure (power source N-1) are shown in Table 3.

[0124] Table 3 Load rate and power supply capacity of each typical grid structure (power source N-1)

[0125]

[0126] Comparing and analyzing the user access methods of six high-reliability grid structures, the user access method of "Double Petal 2" is more flexible and reliable. For specific comparison:

[0127] The user access mode (secondary backbone network) of "Double Petal 2" is divided into four modes: dual access, single ring network (dual access cascade), single ring network (typical mode) and dual ring network. It further improves the user power supply reliability level on the basis of the backbone network "Double Petal";

[0128] The user transformer of "Double Petal 1" is directly connected to the "Double Petal" backbone network, and its reliability relies on the backbone network structure, which is one level lower than that of "Double Petal 2";

[0129] The "diamond-type" user access method, similar to the "double petal 2" method, can be classified into two methods: dual access and single ring network (typical mode). Compared with the "double petal 2" method, there are fewer access methods and lower flexibility;

[0130] The user access method of the "star type" is mainly to access the nearest main network switch station or secondary network ring network cabinet. Although the diversity of access methods is not as good as that of the "double petal 2", the secondary ring network structure with the ring network cabinet as the unit is added, and the overall grid structure level is also flexible and reliable;

[0131] The user access methods of "Snowflake Network" and "Four Corners and Six Connections" are similar and close to traditional access methods, mainly connecting to the nearest ring network cabinet, trunk line or branch line of the backbone network. The flexibility and reliability of the overall grid level are relatively weaker than other structural forms.

[0132] (3) Grid transition method

[0133] Table 4 Implementation paths of typical grid structure transition methods

[0134]

[0135] (4) Secondary configuration comparison analysis

[0136] The six new types of grid structures all use optical fiber longitudinal differential protection for the backbone network. Among the new structures with secondary backbone networks, the "star" structure secondary backbone network uses overcurrent protection, the "diamond" structure secondary backbone network uses optical fiber longitudinal differential protection, and the "double petal 2" structure switch station outgoing line is equipped with overcurrent protection, the secondary backbone network is equipped with intelligent distributed feeder automation, and the low-voltage side of the distribution room connected to the switch station is equipped with self-cutting. In comparison, the protection and automation configuration levels of the backbone network and secondary backbone network of each grid structure are relatively high, and the advantage of "double petal 2" is that the low-voltage side of the distribution room at the user access level is equipped with a self-cutting function, which is more comprehensive than other grid structures.

[0137] Table 5 Comparison of secondary configurations of typical grid structures

[0138]

[0139]

[0140] (5) Power supply reliability comparison

[0141] According to the reporting materials of each grid structure, the power supply reliability data of each structure is summarized as shown in Table 6. Due to the difference in the accuracy of the calculation results of each material (inconsistent decimal places), only a brief comparison is made. Overall, the power supply reliability rankings of various grid structures are: "diamond type", "double petal 1", "double petal 2", "snowflake network", "star type", "four corners and six connections" (cables are better than overhead).

[0142] Table 6 Summary of power supply reliability data for typical grid structures

[0143]

[0144] (6) Cost comparison

[0145] Before conducting unit power supply load cost analysis and comparison for each grid structure, the equipment specifications, model parameters, and construction cost parameters are first set to ensure horizontal comparability, as shown in Table 7.

[0146] Table 7 Equipment parameters

[0147]

[0148] The maximum allowable current and load values ​​for different wire types are shown in Table 8.

[0149] Table 8 Maximum allowable load of trunk line

[0150]

[0151] The power supply capacity of each typical network structure feeder group is calculated, and the results are shown in Table 9.

[0152] Table 9 Power supply capacity of feeder groups in each typical network structure

[0153]

[0154] The scale of various types of equipment in typical networking structures is counted, and the calculation is performed according to the calculation parameter settings to obtain the construction cost of each typical networking structure, as shown in Table 10. (From the perspective of the integrity of the power supply structure, the cost range includes the trunk line, secondary trunk line, various types of ring network switch equipment, distribution transformers and their access lines).

[0155] Table 10 Construction cost of each grid structure

[0156]

[0157] (4) Unit power supply load cost

[0158] According to the calculation results of the power supply capacity and construction cost of the above high-reliability grid structure, the unit power supply load cost is calculated and the results are ranked. The results are shown in Table 11.

[0159] Table 11 Unit power supply load cost of various grid structures

[0160]

[0161] Analysis Table 11 is as follows:

[0162] The "four corners and six connections" structure is an overhead network with low construction costs, so the unit power supply load cost is the lowest; among the other five structures, the unit power supply load costs of "Double Petals 1" and "Double Petals 2" in closed-loop operation modes are significantly higher than those of other open-loop operation grid structures; in the closed-loop operation mode, the unit power supply load cost of "Double Petals 2" is better than that of the "Double Petals 1" structure.

[0163] (7) Based on the calculation results, different 10kV grid schemes are ranked from high to low in terms of power supply reliability and from low to high in terms of unit load investment. The power supply reliability ranking weight is 0.6 points, and the unit load investment ranking weight is 0.4 points. The lower the comprehensive score, the better the comprehensive effect of the grid (the score weight can be adjusted comprehensively according to different regional development and needs to select a more suitable grid scheme).

[0164] In summary, the comprehensive score rankings of the six grids are shown in Table 12 below.

[0165] Table 12 Comprehensive scores of various typical grid structures

[0166]

[0167] It should be understood that the order of execution of the steps in the above embodiment does not necessarily mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0168] Figure 2 is a schematic diagram of the structure of a multi-type grid comparison device 20 provided in an embodiment of the invention, see Figure 2 As shown, the device comprises:

[0169] The acquisition module 21 is used to obtain the operation mode requirements and existing grid structure of the target area.

[0170] The first calculation module 22 is used to determine the power supply capacity of different types of typical grid structures according to the operation mode requirements.

[0171] The second calculation module 23 is used to determine the construction costs of different types of typical grid structures based on the existing grid structures.

[0172] The third calculation module 24 is used to determine the unit power supply load cost of different types of typical grid structures according to the power supply capacity and construction cost.

[0173] Determination module 25 is used to determine the comprehensive scores of different types of typical grid structures based on the unit power supply load costs of different types of typical grid structures and the pre-calculated reliabilities of different types of typical grid structures, and determine the optimal type of typical grid structure based on the comprehensive scores.

[0174] As a possible implementation manner, the first calculation module 22 is used to:

[0175] According to the operation mode requirements, calculate the maximum operating load rate of the trunk line of each type of typical grid structure;

[0176] The power supply capacity of each type of typical grid structure is determined based on the trunk line scale and the maximum operating load rate of the trunk line of each type of typical grid structure.

[0177] As a possible implementation manner, the second calculation module 23 is used to:

[0178] Consistently set equipment parameters for each type of typical grid structure;

[0179] Determine the way to upgrade the existing grid structure to different types of typical grid structures, and determine the construction cost of different types of typical grid structures based on equipment parameters and methods.

[0180] As a possible implementation approach, the reliability of a typical grid structure is calculated using the Failure Mode and Effects Analysis method.

[0181] As a possible implementation method, the reliability of typical grid structures is calculated by failure mode and effect analysis method, including:

[0182] Calculate the failure outage rate and failure outage time of each load point after each facility fails;

[0183] For each load point, the expected value of the fault outage time of the load point is determined according to the fault outage rate and fault outage time corresponding to all the facilities that cause the fault of the load point;

[0184] According to the expected value of fault outage time at each load point and the number of users at each load point, the expected value of the average power supply reliability rate of the typical grid structure is calculated as the reliability index.

[0185] As a possible implementation method, based on the expected value of the fault outage time of each load point and the number of users at each load point, the average power supply of the system of the typical grid structure can be calculated by considering the expected value as a reliability indicator, including:

[0186] according to Calculate the expected average power outage time of the typical grid structure; where S1 is the expected average power outage time of the system, u i is the expected value of the power outage time of the i-th load point, K i is the number of users at the ith load point, K is the total number of users in the system;

[0187] according to Calculate the expected value of the average power supply reliability rate of the system for a typical grid structure; where S2 is the expected value of the average power supply reliability rate of the system, and T is the total hours per unit year.

[0188] As a possible implementation method, the reliability of a typical grid structure is calculated by establishing a simulation model of the typical grid structure.

[0189] As a possible implementation manner, the determination module 25 is used to:

[0190] The first score of each typical grid structure is determined according to the unit power supply load cost; wherein the first score is positively correlated with the unit power supply load cost

[0191] Determine the second score of each typical grid structure according to the reliability; wherein the second score is negatively correlated with the reliability;

[0192] Perform weighted fusion on the first score and the second score of each typical grid structure to obtain a comprehensive score of each typical grid structure;

[0193] The typical grid structure with the lowest comprehensive score is determined as the optimal type of typical grid structure.

[0194] As a possible implementation method, the weight values ​​corresponding to the first score and the second score are determined based on the needs of the target area, combined with the Delphi expert survey method and the fuzzy analysis method, and the entropy theory is used to quantitatively analyze and determine the weight ranking.

[0195] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such 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, and should all be included in the protection scope of the present invention.

Claims

1. A multi-type grid comparison method, characterized in that: include: Obtain the operation mode requirements and existing grid structure of the target area; Determine the power supply capacity of different types of typical grid structures according to the operation mode requirements; Determine the construction cost of different types of typical grid structures based on the existing grid structures; Determining the unit power supply load cost of different types of typical grid structures according to the power supply capacity and the construction cost; Based on the unit power supply load costs of different types of typical grid structures and the pre-calculated reliabilities of different types of typical grid structures, comprehensive scores of different types of typical grid structures are determined, and based on the comprehensive scores, the optimal type of typical grid structure is determined.

2. The multi-type grid comparison method according to claim 1, characterized in that: Determining the power supply capacity of different types of typical grid structures according to the operation mode requirements includes: According to the operation mode requirements, the maximum operating load rate of the trunk line of each type of typical grid structure is calculated; The power supply capacity of each type of typical grid structure is determined based on the trunk line scale and the maximum operating load rate of the trunk line of each type of typical grid structure.

3. The multi-type grid comparison method according to claim 1, characterized in that: Determining the construction costs of different types of typical grid structures based on the existing grid structures includes: Consistently set equipment parameters for each type of typical grid structure; A method for upgrading the existing grid structure to different types of typical grid structures is determined, and based on the equipment parameters and the method, the construction cost of different types of typical grid structures is determined.

4. The multi-type grid comparison method according to claim 1, characterized in that: The reliability of the typical grid structure is calculated by failure mode and effects analysis method.

5. The multi-type grid comparison method according to claim 4, characterized in that: The reliability of the typical grid structure is calculated by failure mode and effect analysis method, including: Calculate the failure outage rate and failure outage time of each load point after each facility fails; For each load point, the expected value of the fault outage time of the load point is determined according to the fault outage rate and fault outage time corresponding to all the facilities that cause the fault of the load point; According to the expected value of the fault outage time of each load point and the number of users at each load point, the expected value of the average power supply reliability rate of the system of the typical grid structure is calculated as the reliability index.

6. The multi-type grid comparison method according to claim 5, characterized in that: The calculation of the average power supply of the system of the typical grid structure according to the expected value of the fault power outage time of each load point and the number of users at each load point may consider the expected value as a reliability index, including: according to Calculate the expected average power outage time of the typical grid structure; where S1 is the expected average power outage time of the system, u i is the expected value of the power outage time of the i-th load point, K i is the number of users at the ith load point, K is the total number of users in the system; according to Calculate the expected value of the average power supply reliability rate of the system of the typical grid structure; where S2 is the expected value of the average power supply reliability rate of the system, and T is the total hours per unit year.

7. The multi-type grid comparison method according to claim 1, characterized in that: The reliability of the typical grid structure is calculated by establishing a simulation model of the typical grid structure.

8. The multi-type grid comparison method according to any one of claims 1 to 7, characterized in that: The unit power supply load costs of different types of typical grid structures and the pre-calculated reliabilities of different types of typical grid structures are used to determine the comprehensive scores of different types of typical grid structures, and the optimal type of typical grid structure is determined according to the comprehensive scores, including: Determine a first score for each typical grid structure according to the unit power supply load cost; wherein the first score is positively correlated with the unit power supply load cost; Determine a second score for each typical grid structure according to the reliability; wherein the second score is negatively correlated with the reliability; Perform weighted fusion on the first score and the second score of each typical grid structure to obtain a comprehensive score of each typical grid structure; The typical grid structure with the lowest comprehensive score is determined as the optimal type of typical grid structure.

9. The multi-type grid comparison method according to claim 8, characterized in that: The weight values ​​corresponding to the first score and the second score are determined based on the needs of the target area, combined with the Delphi expert survey method and the fuzzy analysis method, and using the entropy theory to quantitatively analyze and determine the weight ranking.

10. A multi-type grid comparison device, characterized in that: include: An acquisition module is used to obtain the operation mode requirements and existing grid structure of the target area; A first calculation module is used to determine the power supply capacity of different types of typical grid structures according to the operation mode requirements; A second calculation module is used to determine the construction cost of different types of typical grid structures based on the existing grid structures; A third calculation module is used to determine the unit power supply load cost of different types of typical grid structures according to the power supply capacity and the construction cost; A determination module is used to determine the comprehensive scores of different types of typical grid structures based on the unit power supply load costs of different types of typical grid structures and the pre-calculated reliabilities of different types of typical grid structures, and to determine the optimal type of typical grid structure based on the comprehensive scores.

Images