VBA-based main network line loss analysis and calculation method

Abstract

The invention relates to a VBA-based main network line loss analysis and calculation method. The method comprises the following steps of 1, performing data analysis on an integrated electric quantity and line loss management system; step 2, constructing a CIM-based power distribution network line loss calculation method to realize accurate calculation of line loss; 3, calculating the line loss of a part of measurement information lacking measured data by adopting a power distribution network line loss calculation method based on incomplete measured information; step 4, constructing a gateway model based on VBA; step 5, adopting an XLAM loading item started along with a gateway model list to provide a one-stop reference measurement and calculation service for the regional main network element line loss; the method has the advantages of improving the accuracy of main network line loss calculation, reducing the workload of personnel and being good in universality.

Description

Technical Field

[0001] The present invention belongs to the technical field of power grid line loss analysis, and in particular relates to a main grid line loss analysis and calculation method based on VBA. Background Art

[0002] When analyzing and calculating the line loss of the main network, its data comes from the integrated power and line loss management system. Since the integrated power and line loss management system integrates the data of multiple business systems, the system functions are relatively complex. In addition, the current power grid is large in size, complex in structure, large in scale, with many components and complex in operation mode. Therefore, there are more prominent problems such as huge calculation amount, difficult analysis and frequent replacement of meters for the line loss of the regional main network at the same time. In addition, for the local distribution network, there are many nodes and most load nodes lack measured data. Since the distribution network has few measuring meters and the measurement information on each load side is incomplete, it is difficult to directly use the flow to calculate the network line loss. The line loss analysis depends on the basic data model of the power grid, but due to the lack of a unified information model, the data matching rate between the systems is low, resulting in inaccurate calculation of the distribution network line loss. Therefore, it is very necessary to provide a main network line loss analysis and calculation method based on VBA that improves the accuracy of the main network line loss calculation, reduces the workload of personnel and has good versatility. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a main network line loss analysis and calculation method based on VBA with good versatility, which improves the accuracy of main network line loss calculation, reduces the workload of personnel, and has good versatility.

[0004] The object of the present invention is achieved by: a main network line loss analysis and calculation method based on VBA, the method comprising the following steps:

[0005] Step 1: Data analysis of the integrated power and line loss management system;

[0006] Step 2: Construct a distribution network line loss calculation method based on CIM to achieve accurate calculation of line loss;

[0007] Step 3: Use a distribution network line loss calculation method based on incomplete measured information to calculate line losses for some measured information that lacks measured data;

[0008] Step 4: Build a gateway model based on VBA;

[0009] Step 5: Use the XLAM add-in started with the gateway model list to provide a one-stop reference calculation service for the line loss of regional main grid components.

[0010] The data analysis for the integrated power and line loss management system in step 1 specifically includes the following steps:

[0011] Step 1.1: Study the line loss of main grid components in the integrated power and line loss management system, starting from the substation and line archives, the cross-reference relationship between switches and metering points, the model configuration of line loss components, the configuration of the voltage divider line loss points, and master the characteristics of regional main grid components;

[0012] Step 1.2: Combine the metering points provided in the electricity consumption information collection system and the electric energy collection system to perform a simulation calculation of the electricity consumption;

[0013] Step 1.3: According to the requirements for the main network line loss rate, the calculated results are analyzed and judged to determine the correlation between the components and the metering points;

[0014] Step 1.4: At the same time, conduct an in-depth study of the characteristics of the energy meter and analyze its operating characteristics from the aspects of voltage, current, and power factor to lay the foundation for analyzing the line loss of abnormal components.

[0015] The construction of the CIM-based distribution network line loss calculation method in step 2 to achieve accurate calculation of line loss is specifically as follows: the distribution network line loss calculation requires obtaining distribution network equipment parameters, topology, operation data and switch status, and exporting the operation results, which specifically includes the following steps:

[0016] Step 2.1: Mathematical model for calculating line loss in distribution network: Line loss in distribution network mainly includes the loss of distribution line and the core loss and winding loss of distribution transformer;

[0017] Step 2.2: Distribution network line loss CIM model extension.

[0018] The mathematical model for calculating the distribution network line loss in step 2.1 specifically includes the following steps:

[0019] Step 2.11: Calculation of line loss: The calculation of distribution network line loss is a combination of the average current method and the equivalent resistance method. The calculation formula of line loss is: Where W l is the power loss of the feeder line; k is the shape factor; I av is the average current at the feeder head end; R el is the equivalent resistance of the feeder line; T is the number of days in the calculation month; W p , W q are the monthly active power and monthly reactive power at the feeder head end respectively; i is the resistance of the i-th line; S j is the capacity of the jth transformer; K i is the average load rate of the i-th transformer; m is the number of transformers; n is the number of line sections; m i The number of transformers on all branch lines under the i-th branch line;

[0020] Step 2.12: Calculation of transformer loss: The average current method is often used to calculate the variable loss of distribution transformers. The maximum and minimum values ​​of the transformer variable loss are calculated one by one, and finally these losses are accumulated to form the transformer variable loss. The loss power calculation formula for a single transformer is: Where P k is the load loss of the transformer; P0 is the no-load loss of the transformer; S is the rated capacity of the transformer; T is the number of hours per month; k is the shape factor; U is the rated voltage; I av is the average current of the transformer.

[0021] The distribution network line loss CIM model extension in step 2.2 is specifically as follows: modeling the distribution network line loss, first establishing the distribution network line loss class as a basic class to represent the characteristics of the distribution network line loss. When calculating the line loss of the distribution network, the monthly active power, monthly reactive power, and calculation month days information are required to calculate the monthly average current and shape factor; line resistance and transformer capacity information are required to calculate the equivalent resistance; transformer no-load loss, load loss, and transformer capacity information are required to calculate transformer loss; wherein ① the power grid line loss class mainly models the line and transformer line loss information, and the specific values ​​of its inherent attributes need to be extracted from the distribution network model provided by the DMS and the real-time data information provided by the SCADA. For this reason, the measurement information class, branch information class, and node information class are continued to be expanded on the basis of the CIM model. Class; ② The measurement information class mainly includes determining the measurement point (node ​​number and branch number) to obtain the measurement value (such as instantaneous current, etc.), measurement type (active or reactive) and measurement error and other information, so the measurement point location, measurement type, measurement value, and measurement error attributes are added to represent this information; ③ The node information class is used to define the node information, including the node number, node admittance, and branch information connected to the node, so the node number, node type, node conductance, node admittance, upstream branch, and downstream branch attributes are added to represent this information; ④ The branch information class is used to define the branch information, including the branch number, branch impedance, and the nodes at both ends of the branch, so the branch number, head node, end node, branch resistance, and branch reactance attributes are added to represent this information.

[0022] The method for calculating the line loss of the distribution network based on incomplete measured information in step 3 is used to calculate the line loss of the partial measured information lacking measured data, and specifically includes the following steps:

[0023] Step 3.1: General definition of the basic model;

[0024] Step 3.2: Calculation method.

[0025] The general definition of the basic model in step 3.1 is as follows: The power consumption is mainly composed of line resistance and iron loss and copper loss in the transformer. The power loss caused by line resistance during the load current or power flowing through the line in time t is: Among them, ΔP is the active power loss of the line; R is the line resistance; S is the three-phase power passing through the line; U is the actual line voltage of the line; I is the current passing through the line; because the change law of the load is not easy to express with a function, for the power grid with a known load curve, when the load is expressed by current, the above formula can be rewritten as: If Δt = 1, the power loss for one day is: In the formula, is the 24-hour RMS current of the line.

[0026] The calculation method in step 3.2 is as follows: as long as the power or current passing through each component is known, the electric energy loss can be calculated. The distribution line is generally derived from the substation. In most cases, the power or electricity is only measured on the substation side. There is generally no meter measurement at the line branch point. When the actual measured load of the head end representative is known, the segmented calculation method can be used, which specifically includes the following steps:

[0027] Step 3.21: Determine the number of line segments and segment resistance values: In the network wiring diagram, the connection points of high-voltage users and distribution transformers are all load points. The connection points between two adjacent load points or between a load point and an adjacent branch line, as well as the connection points between two adjacent branch lines, are all considered as a segment. The resistance value of each segment can be obtained from the line parameters of each segment.

[0028] Step 3.22: Determine the maximum current I at the line outlet based on the daily measurement record of the representative at the line head end. max , average current I pj , RMS current I jf , if the actual measured currents on the day are I1, I2, ..., I 24 ,but

[0029] Step 3.23: Correct the representative daily current: If the first-end representative daily power transmission is A1, and the monthly power transmission is A2, then the daily average power is If the difference between A1 and A3 is large, the representative daily current should be corrected as follows:

[0030] Step 3.24: Determine the maximum load current of high-voltage users and the maximum load current of the high-voltage side of the distribution transformer based on the measured load. High-voltage users generally have representative daily measured current or monthly energy records. The average current of high-voltage users is: If there is no actual current record, the maximum current of the high-voltage user can be obtained from the head end I′ max and I′ pjValue estimation: Right now Among them, A i is the electric energy of the high-voltage user at the i-th node in time t; U is the line voltage at the i-th node; The power factor of the ith node; the distribution transformers with measured load records can be treated in the same way as high-voltage users. The maximum currents of each high-voltage user and the distribution transformer with measured load records are calculated one by one and then added together to obtain the sum of the maximum currents of all high-voltage users and the maximum currents of the distribution transformers with measured load records. max ;

[0031] Step 3.25: Determine the maximum current on the high-voltage side of the distribution transformer without measured load records: The sum of the maximum currents of the distribution transformer without measured load records I B∑ , is the maximum current I′ at the first end max Subtract the sum of the maximum current of the high-voltage user and the maximum current of the distribution transformer with measured current records I max∑ , that is: I BΣ =I′ max -I maxΣ , after allocating the capacity of each distribution transformer without measured load, the maximum current of each transformer can be obtained: Among them, I BKm is the maximum current of the Kth distribution transformer without measured load record; I B∑ The sum of the maximum currents of distribution transformers without actual load records; S ∑ is the total capacity of the distribution transformer without measured load records; S eK The rated capacity of the Kth distribution transformer without actual load measurement record;

[0032] Step 3.26: Calculate the equivalent resistance of the line: The loss generated when the maximum current at the head end of the line passes through the equivalent resistance should be exactly equal to the loss generated when each line runs at the actual maximum current in the same time period, that is, the equivalent resistance is: Among them, R d is the equivalent resistance of the line; R k is the resistance of the kth line; I max,k is the maximum current of the kth line; I′ max is the maximum current at the first end after correction;

[0033] Step 3.27: Calculate the line power loss within time t:

[0034] Step 3.28: Calculate the power losses of the distribution transformer: Fixed losses: Among them, ΔP oi is the short-circuit loss of the i-th transformer.

[0035] The construction of the VBA-based gateway model in step 4 specifically includes the following steps:

[0036] Step 4.1: Analyze the main grid component model structure, classify and summarize the components, optimize them using VBA, use component names, switches, metering points, calculation relationships, and key information of calculated electricity, use different color areas to represent the input and output metering points of the component model, refer to the metering point exchange records of the integrated electricity and line loss system, convert the updated meter exchange records into the electricity of the same period and include them in the metering points, and finally generate the metering point electricity calculation;

[0037] Step 4.2: Use a VBA-based user form to display the component line loss rate, and use vsFlexGrid to distinguish the line loss rate of all components from the components with excessive line loss rate;

[0038] Step 4.3: According to the control mechanism of the whitelist of line loss rate of main grid components, the whitelist is verified, and the components that still do not meet the line loss rate requirements are specially marked. Finally, the line loss rate of the entire region during the same period is generated for reference.

[0039] The step 5 of using the XLAM loading module started with the gateway model to provide a one-stop reference calculation service for the line loss of the regional main grid components specifically includes the following steps:

[0040] Step 5.1: Use the Excel-based real-time loading module to perform power and line loss statistical analysis on the gateway model at any time;

[0041] Step 5.2: As the gateway model is started, the analysis and statistics tool module is automatically loaded, which improves work efficiency and is deeply integrated into the Excel tool module;

[0042] Step 5.3: Integrate the display mode of the component model, use a separate line loss dedicated tool module, create a line loss calculation form, associate the table change records, format the line loss table, analyze the system power, and provide a one-stop reference measurement service for the regional main network component line loss, effectively improving the regional main network line loss rate.

[0043] Beneficial effects of the present invention: The present invention is a main network line loss analysis and calculation method based on VBA. In use, the present invention focuses on the gateway model table downloaded by the integrated power and line loss system, optimizes the display mode based on VBA, introduces the electric energy meter replacement record, calculates the power of the metering point, automatically generates the synchronous line loss, and automatically verifies the white list. Multiple key technologies provide a reliable main network component line loss rate reference for line loss management personnel, and generally improves the synchronous line loss rate of the regional main network; at the same time, the table downloaded by the integrated power and line loss system is in Excel format, and the present invention adopts Microsoft Office The XLAM add-in of Excel is started with the Excel synchronous line loss component model table, which is convenient for line loss management personnel to analyze the main network component line loss rate at any time; the main network line loss analysis and calculation method of the present invention can realize the easy calculation of the main network line loss, and can quickly find problems from the calculation results, solve the problems, reduce the workload of personnel, and improve the synchronous line loss rate of the regional main network; the present invention constructs a distribution network line loss calculation method based on CIM, expands the CIM model according to the mathematical model of line loss calculation, establishes distribution network line loss class and related classes, and realizes the accurate calculation of line loss. The present invention has the advantages of improving the accuracy of main network line loss calculation, reducing personnel workload, and good versatility. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 The present invention is a flow chart of a method for calculating line loss in a distribution network based on incomplete measured information.

[0045] Figure 2 The equivalent circuit diagram for calculating the network wiring of a certain city of the present invention is provided. DETAILED DESCRIPTION

[0046] The present invention will be further described below in conjunction with the accompanying drawings.

[0047] Example 1

[0048] like Figure 1-2 As shown, a main network line loss analysis and calculation method based on VBA, the method comprises the following steps:

[0049] Step 1: Data analysis of the integrated power and line loss management system;

[0050] Step 2: Construct a distribution network line loss calculation method based on CIM to achieve accurate calculation of line loss;

[0051] Step 3: Use a distribution network line loss calculation method based on incomplete measured information to calculate line losses for some measured information that lacks measured data;

[0052] Step 4: Build a VBA-based gateway model;

[0053] Step 5: Use the XLAM add-in started with the gateway model list to provide a one-stop reference calculation service for the line loss of regional main grid components.

[0054] The data analysis for the integrated power and line loss management system in step 1 specifically includes the following steps:

[0055] Step 1.1: Study the line loss of main grid components in the integrated power and line loss management system, starting from the substation and line archives, the cross-reference relationship between switches and metering points, the model configuration of line loss components, the configuration of the voltage divider line loss points, and master the characteristics of regional main grid components;

[0056] Step 1.2: Combine the metering points provided in the electricity consumption information collection system and the electric energy collection system to perform a simulation calculation of the electricity consumption;

[0057] Step 1.3: According to the requirements for the main network line loss rate, the calculated results are analyzed and judged to determine the correlation between the components and the metering points;

[0058] Step 1.4: At the same time, conduct an in-depth study of the characteristics of the energy meter and analyze its operating characteristics from the aspects of voltage, current, and power factor to lay the foundation for analyzing the line loss of abnormal components.

[0059] The construction of the VBA-based gateway model in step 4 specifically includes the following steps:

[0060] Step 4.1: Analyze the main grid component model structure, classify and summarize the components, optimize them using VBA, use component names, switches, metering points, calculation relationships, and key information of calculated electricity, use different color areas to represent the input and output metering points of the component model, refer to the metering point exchange records of the integrated electricity and line loss system, convert the updated meter exchange records into the electricity of the same period and include them in the metering points, and finally generate the metering point electricity calculation;

[0061] Step 4.2: Use a VBA-based user form to display the component line loss rate, and use vsFlexGrid to distinguish the line loss rate of all components from the components with excessive line loss rate;

[0062] Step 4.3: According to the control mechanism of the whitelist of line loss rate of main grid components, the whitelist is verified, and the components that still do not meet the line loss rate requirements are specially marked. Finally, the line loss rate of the entire region during the same period is generated for reference.

[0063] The step 5 of using the XLAM loading module started with the gateway model to provide a one-stop reference calculation service for the line loss of the regional main grid components specifically includes the following steps:

[0064] Step 5.1: Use the Excel-based real-time loading module to perform power and line loss statistical analysis on the gateway model at any time;

[0065] Step 5.2: As the gateway model is started, the analysis and statistics tool module is automatically loaded, which improves work efficiency and is deeply integrated into the Excel tool module;

[0066] Step 5.3: Integrate the display mode of the component model, use a separate line loss dedicated tool module, create a line loss calculation form, associate the table change records, format the line loss table, analyze the system power, and provide a one-stop reference measurement service for the regional main network component line loss, effectively improving the regional main network line loss rate.

[0067] The present invention is a main network line loss analysis and calculation method based on VBA. In use, the present invention focuses on the gateway model table downloaded by the integrated power and line loss system, optimizes the display mode based on VBA, introduces the electric energy meter replacement record, calculates the power of the metering point, automatically generates the synchronous line loss, and automatically verifies the white list. Multiple key technologies provide a reliable main network component line loss rate reference for line loss management personnel, and generally improves the synchronous line loss rate of the regional main network; at the same time, the table downloaded by the integrated power and line loss system is in Excel format, and the present invention adopts Microsoft Office The XLAM add-in of Excel is started with the Excel synchronous line loss component model table, which is convenient for line loss management personnel to analyze the main network component line loss rate at any time; the main network line loss analysis and calculation method of the present invention can realize the easy calculation of the main network line loss, and can quickly find problems from the calculation results, solve the problems, reduce the workload of personnel, and improve the synchronous line loss rate of the regional main network; the present invention constructs a distribution network line loss calculation method based on CIM, expands the CIM model according to the mathematical model of line loss calculation, establishes distribution network line loss class and related classes, and realizes the accurate calculation of line loss. The present invention has the advantages of improving the accuracy of main network line loss calculation, reducing personnel workload, and good versatility.

[0068] Example 2

[0069] like Figure 1-2 As shown, a main network line loss analysis and calculation method based on VBA, the method comprises the following steps:

[0070] Step 1: Data analysis of the integrated power and line loss management system;

[0071] Step 2: Construct a distribution network line loss calculation method based on CIM to achieve accurate calculation of line loss;

[0072] Step 3: Use a distribution network line loss calculation method based on incomplete measured information to calculate line losses for some measured information that lacks measured data;

[0073] Step 4: Build a VBA-based gateway model;

[0074] Step 5: Use the XLAM add-in started with the gateway model list to provide a one-stop reference calculation service for the line loss of regional main grid components.

[0075] The construction of the CIM-based distribution network line loss calculation method in step 2 to achieve accurate calculation of line loss is specifically as follows: the distribution network line loss calculation requires obtaining distribution network equipment parameters, topology, operation data and switch status, and exporting the operation results, which specifically includes the following steps:

[0076] Step 2.1: Mathematical model for calculating line loss in distribution network: Line loss in distribution network mainly includes the loss of distribution line and the core loss and winding loss of distribution transformer;

[0077] Step 2.2: Distribution network line loss CIM model extension.

[0078] The mathematical model for calculating the distribution network line loss in step 2.1 specifically includes the following steps:

[0079] Step 2.11: Calculation of line loss: The calculation of distribution network line loss is a combination of the average current method and the equivalent resistance method. The calculation formula of line loss is: Where W l is the power loss of the feeder line; k is the shape factor; I av is the average current at the feeder head end; R el is the equivalent resistance of the feeder line; T is the number of days in the calculation month; W p , W q are the monthly active power and monthly reactive power at the feeder head end respectively; i is the resistance of the i-th line; S j is the capacity of the jth transformer; K i is the average load rate of the i-th transformer; m is the number of transformers; n is the number of line sections; m i The number of transformers on all branch lines under the i-th branch line;

[0080] Step 2.12: Calculation of transformer loss: The average current method is often used to calculate the variable loss of distribution transformers. The maximum and minimum values ​​of the transformer variable loss are calculated one by one, and finally these losses are accumulated to form the transformer variable loss. The loss power calculation formula for a single transformer is: Where P k is the load loss of the transformer; P0 is the no-load loss of the transformer; S is the rated capacity of the transformer; T is the number of hours per month; k is the shape factor; U is the rated voltage; I av is the average current of the transformer.

[0081] The distribution network line loss CIM model extension in step 2.2 is specifically as follows: modeling the distribution network line loss, first establishing the distribution network line loss class as a basic class to represent the characteristics of the distribution network line loss. When calculating the line loss of the distribution network, the monthly active power, monthly reactive power, and calculation month days information are required to calculate the monthly average current and shape factor; line resistance and transformer capacity information are required to calculate the equivalent resistance; transformer no-load loss, load loss, and transformer capacity information are required to calculate transformer loss; wherein ① the power grid line loss class mainly models the line and transformer line loss information, and the specific values ​​of its inherent attributes need to be extracted from the distribution network model provided by the DMS and the real-time data information provided by the SCADA. For this reason, the measurement information class, branch information class, and node information class are continued to be expanded on the basis of the CIM model. Class; ② The measurement information class mainly includes determining the measurement point (node ​​number and branch number) to obtain the measurement value (such as instantaneous current, etc.), measurement type (active or reactive) and measurement error and other information, so the measurement point location, measurement type, measurement value, and measurement error attributes are added to represent this information; ③ The node information class is used to define the node information, including the node number, node admittance, and branch information connected to the node, so the node number, node type, node conductance, node admittance, upstream branch, and downstream branch attributes are added to represent this information; ④ The branch information class is used to define the branch information, including the branch number, branch impedance, and the nodes at both ends of the branch, so the branch number, head node, end node, branch resistance, and branch reactance attributes are added to represent this information.

[0082] The method for calculating the line loss of the distribution network based on incomplete measured information in step 3 is used to calculate the line loss of the partial measured information lacking measured data, and specifically includes the following steps:

[0083] Step 3.1: General definition of the basic model;

[0084] Step 3.2: Calculation method.

[0085] The general definition of the basic model in step 3.1 is as follows: The power consumption is mainly composed of line resistance and iron loss and copper loss in the transformer. The power loss caused by line resistance during the load current or power flowing through the line in time t is: Among them, ΔP is the active power loss of the line; R is the line resistance; S is the three-phase power passing through the line; U is the actual line voltage of the line; I is the current passing through the line; because the change law of the load is not easy to express with a function, for the power grid with a known load curve, when the load is expressed by current, the above formula can be rewritten as: If Δt = 1, the power loss for one day is: In the formula, is the 24-hour RMS current of the line.

[0086] The calculation method in step 3.2 is as follows: as long as the power or current passing through each component is known, the electric energy loss can be calculated. The distribution line is generally derived from the substation. In most cases, the power or electricity is only measured on the substation side. There is generally no meter measurement at the line branch point. When the actual measured load of the head end representative is known, the segmented calculation method can be used, which specifically includes the following steps:

[0087] Step 3.21: Determine the number of line segments and segment resistance values: In the network wiring diagram, the connection points of high-voltage users and distribution transformers are all load points. The connection points between two adjacent load points or between a load point and an adjacent branch line, as well as the connection points between two adjacent branch lines, are all considered as a segment. The resistance value of each segment can be obtained from the line parameters of each segment.

[0088] Step 3.22: Determine the maximum current I at the line outlet based on the daily measurement record of the representative at the line head end. max , average current I pj , RMS current I jf , if the actual measured currents on the day are I1, I2, ..., I 24 ,but

[0089] Step 3.23: Correct the representative daily current: If the first-end representative daily power transmission is A1, and the monthly power transmission is A2, then the daily average power is If the difference between A1 and A3 is large, the representative daily current should be corrected as follows:

[0090] Step 3.24: Determine the maximum load current of high-voltage users and the maximum load current of the high-voltage side of the distribution transformer based on the measured load. High-voltage users generally have representative daily measured current or monthly energy records. The average current of high-voltage users is: If there is no actual current record, the maximum current of the high-voltage user can be obtained from the head end I′ max and I′ pj Value estimation: Right now Among them, A i is the electric energy of the high-voltage user at the i-th node in time t; U is the line voltage at the i-th node; The power factor of the ith node; the distribution transformers with measured load records can be treated in the same way as high-voltage users. The maximum currents of each high-voltage user and the distribution transformer with measured load records are calculated one by one and then added together to obtain the sum of the maximum currents of all high-voltage users and the maximum currents of the distribution transformers with measured load records. max ;

[0091] Step 3.25: Determine the maximum current on the high-voltage side of the distribution transformer without measured load records: The sum of the maximum currents of the distribution transformer without measured load records I B∑ , is the maximum current I′ at the first end max Subtract the sum of the maximum current of the high-voltage user and the maximum current of the distribution transformer with measured current records I maxΣ , that is: I BΣ =I′ max -I maxΣ , after allocating the capacity of each distribution transformer without measured load, the maximum current of each transformer can be obtained: Among them, I BKm is the maximum current of the Kth distribution transformer without measured load record; I BΣ The sum of the maximum currents of distribution transformers without actual load records; S Σ is the total capacity of the distribution transformer without measured load records; S eK The rated capacity of the Kth distribution transformer without actual load measurement record;

[0092] Step 3.26: Calculate the equivalent resistance of the line: The loss generated when the maximum current at the head end of the line passes through the equivalent resistance should be exactly equal to the loss generated when each line runs at the actual maximum current in the same time period, that is, the equivalent resistance is: Among them, R d is the equivalent resistance of the line; R k is the resistance of the kth line; I max,k is the maximum current of the kth line; I′ max is the maximum current at the first end after correction;

[0093] Step 3.27: Calculate the line power loss within time t:

[0094] Step 3.28: Calculate the power losses of the distribution transformer: Fixed losses: Among them, ΔP oi is the short-circuit loss of the i-th transformer.

[0095] In this embodiment, the example analysis: This example is a 66kv substation in a certain city, and its network wiring and original data are as follows Figure 2 , the line impedance is represented by R+jx, the monthly electric energy unit of high-voltage users is 10,000 kw.h, the first end in the figure is node 0, nodes 8, 7, 12, and 15 are distribution transformer nodes without measured load records (in this example, distribution transformers are all treated as having no measured load), and the rest are high-voltage user nodes. The result calculated by the traditional regression method is: ΔA L =1.3713 million kwh, ΔA L % = 2.23%;

[0096] The first end represents the daily load curve, as shown in Table 1, and the calculated result ΔA L =1.3856 million kwh, ΔA L % = 2.17%, the calculation result is consistent with the result obtained by the network loss calculation program using the regression analysis method. The calculation example results show that under the condition that all measured values ​​are accurate, the calculation error of the method of the present invention does not exceed 1%, which has great use value in practical applications;

[0097] Table 1 Representative daily load curve at the head end

[0098]

[0099]

[0100] The present invention is a main network line loss analysis and calculation method based on VBA. In use, the present invention focuses on the gateway model table downloaded by the integrated power and line loss system, optimizes the display mode based on VBA, introduces the electric energy meter replacement record, calculates the power of the metering point, automatically generates the synchronous line loss, and automatically verifies the white list. Multiple key technologies provide a reliable main network component line loss rate reference for line loss management personnel, and generally improves the synchronous line loss rate of the regional main network; at the same time, the table downloaded by the integrated power and line loss system is in Excel format, and the present invention adopts Microsoft Office The XLAM add-in of Excel is started with the Excel synchronous line loss component model table, which is convenient for line loss management personnel to analyze the main network component line loss rate at any time; the main network line loss analysis and calculation method of the present invention can realize the easy calculation of the main network line loss, and can quickly find problems from the calculation results, solve the problems, reduce the workload of personnel, and improve the synchronous line loss rate of the regional main network; the present invention constructs a distribution network line loss calculation method based on CIM, expands the CIM model according to the mathematical model of line loss calculation, establishes distribution network line loss class and related classes, and realizes the accurate calculation of line loss. The present invention has the advantages of improving the accuracy of main network line loss calculation, reducing personnel workload, and good versatility.

Claims

1. The main network line loss analysis and calculation method based on VBA is characterized by: The method comprises the following steps: Step 1: Data analysis of the integrated power and line loss management system; Step 2: Construct a distribution network line loss calculation method based on CIM to achieve accurate calculation of line loss; Step 3: Use a distribution network line loss calculation method based on incomplete measured information to calculate line losses for some measured information that lacks measured data; Step 4: Build a gateway model based on VBA; Step 5: Use the XLAM add-in started with the gateway model list to provide a one-stop reference calculation service for the line loss of regional main grid components.

2. The main network line loss analysis and calculation method based on VBA as claimed in claim 1, characterized in that: The data analysis for the integrated power and line loss management system in step 1 specifically includes the following steps: Step 1.1: Study the line loss of main grid components in the integrated power and line loss management system, starting from the substation and line archives, the cross-reference relationship between switches and metering points, the model configuration of line loss components, the configuration of the voltage divider line loss points, and master the characteristics of regional main grid components; Step 1.2: Combine the metering points provided in the electricity consumption information collection system and the electric energy collection system to perform a simulation calculation of the electricity consumption; Step 1.3: According to the requirements for the main network line loss rate, the calculated results are analyzed and judged to determine the correlation between the components and the metering points; Step 1.4: At the same time, conduct an in-depth study of the characteristics of the energy meter and analyze its operating characteristics from the aspects of voltage, current, and power factor to lay the foundation for analyzing the line loss of abnormal components.

3. The main network line loss analysis and calculation method based on VBA as claimed in claim 1, characterized in that: The construction of the CIM-based distribution network line loss calculation method in step 2 to achieve accurate calculation of line loss is specifically as follows: the distribution network line loss calculation requires obtaining distribution network equipment parameters, topology, operation data and switch status, and exporting the operation results, which specifically includes the following steps: Step 2.1: Mathematical model for calculating line loss in distribution network: Line loss in distribution network mainly includes the loss of distribution line and the core loss and winding loss of distribution transformer; Step 2.2: Distribution network line loss CIM model extension.

4. The main network line loss analysis and calculation method based on VBA as claimed in claim 3 is characterized by: The mathematical model for calculating the distribution network line loss in step 2.1 specifically includes the following steps: Step 2.11: Calculation of line loss: The calculation of distribution network line loss is a combination of the average current method and the equivalent resistance method. The calculation formula of line loss is: W l =k 2 ×I a 2 v ×R el ×T, Where W l is the power loss of the feeder line; k is the shape factor; I av is the average current at the feeder head end; R el is the equivalent resistance of the feeder line; T is the number of days in the calculation month; W p , W q are the monthly active power and monthly reactive power at the feeder head end respectively; i is the resistance of the i-th line; S j is the capacity of the jth transformer; K i is the average load rate of the i-th transformer; m is the number of transformers; n is the number of line sections; m i The number of transformers on all branch lines under the i-th branch line; Step 2.12: Calculation of transformer loss: The average current method is often used to calculate the variable loss of distribution transformers. The maximum and minimum values ​​of the transformer variable loss are calculated one by one, and finally these losses are accumulated to form the transformer variable loss. The loss power calculation formula for a single transformer is: Where P k is the load loss of the transformer; P0 is the no-load loss of the transformer; S is the rated capacity of the transformer; T is the number of hours per month; k is the shape factor; U is the rated voltage; I av is the average current of the transformer.

5. The main network line loss analysis and calculation method based on VBA as claimed in claim 3 is characterized by: The distribution network line loss CIM model extension in step 2.2 is specifically as follows: modeling the distribution network line loss, first establishing the distribution network line loss class as a basic class to represent the characteristics of the distribution network line loss. When calculating the line loss of the distribution network, the monthly active power, monthly reactive power, and calculation month days information are required to calculate the monthly average current and shape factor; line resistance and transformer capacity information are required to calculate the equivalent resistance; transformer no-load loss, load loss, and transformer capacity information are required to calculate transformer loss; wherein ① the power grid line loss class mainly models the line and transformer line loss information, and the specific values ​​of its inherent attributes need to be extracted from the distribution network model provided by the DMS and the real-time data information provided by the SCADA. For this reason, the measurement information class, branch information class, and node information class are continued to be expanded on the basis of the CIM model. Class; ② The measurement information class mainly includes determining the measurement point (node ​​number and branch number) to obtain the measurement value (such as instantaneous current, etc.), measurement type (active or reactive) and measurement error and other information, so the measurement point location, measurement type, measurement value, and measurement error attributes are added to represent this information; ③ The node information class is used to define the node information, including the node number, node admittance, and branch information connected to the node, so the node number, node type, node conductance, node admittance, upstream branch, and downstream branch attributes are added to represent this information; ④ The branch information class is used to define the branch information, including the branch number, branch impedance, and the nodes at both ends of the branch, so the branch number, head node, end node, branch resistance, and branch reactance attributes are added to represent this information.

6. The main network line loss analysis and calculation method based on VBA as claimed in claim 1, characterized in that: The method for calculating the line loss of the distribution network based on incomplete measured information in step 3 is used to calculate the line loss of the partial measured information lacking measured data, and specifically includes the following steps: Step 3.1: General definition of the basic model; Step 3.2: Calculation method.

7. The main network line loss analysis and calculation method based on VBA as claimed in claim 6, characterized in that: The general definition of the basic model in step 3.1 is as follows: The power consumption is mainly composed of line resistance and iron loss and copper loss in the transformer. The power loss caused by line resistance during the load current or power flowing through the line in time t is: Among them, ΔP is the active power loss of the line; R is the line resistance; S is the three-phase power passing through the line; U is the actual line voltage of the line; I is the current passing through the line; because the change law of the load is not easy to express with a function, for the power grid with a known load curve, when the load is expressed by current, the above formula can be rewritten as: If Δt = 1, the power loss for one day is: In the formula, is the 24-hour RMS current of the line.

8. The main network line loss analysis and calculation method based on VBA as claimed in claim 6, characterized in that: The calculation method in step 3.2 is as follows: as long as the power or current passing through each component is known, the electric energy loss can be calculated. The distribution line is generally derived from the substation. In most cases, the power or electricity is only measured on the substation side. There is generally no meter measurement at the line branch point. When the actual measured load of the head end representative is known, the segmented calculation method can be used, which specifically includes the following steps: Step 3.21: Determine the number of line segments and segment resistance values: In the network wiring diagram, the connection points of high-voltage users and distribution transformers are all load points. The connection points between two adjacent load points or between a load point and an adjacent branch line, as well as the connection points between two adjacent branch lines, are all considered as a segment. The resistance value of each segment can be obtained from the line parameters of each segment. Step 3.22: Determine the maximum current I at the line outlet based on the daily measurement record of the representative at the line head end. max , average current I pj , RMS current I jf , if the actual measured currents on the day are I1, I2, ..., I 24 ,but Step 3.23: Correct the representative daily current: If the first-end representative daily power transmission is A1, and the monthly power transmission is A2, then the daily average power is If the difference between A1 and A3 is large, the representative daily current should be corrected as follows: Step 3.24: Determine the maximum load current of high-voltage users and the maximum load current of the high-voltage side of the distribution transformer based on the measured load. High-voltage users generally have representative daily measured current or monthly energy records. The average current of high-voltage users is: If there is no actual current record, the maximum current of the high-voltage user can be obtained from the head end I′ max and I′ pj Value estimation: Right now Among them, A i is the electric energy of the high-voltage user at the i-th node in time t; U is the line voltage at the i-th node; The power factor of the ith node; the distribution transformers with measured load records can be treated in the same way as high-voltage users. The maximum currents of each high-voltage user and the distribution transformer with measured load records are calculated one by one and then added together to obtain the sum of the maximum currents of all high-voltage users and the maximum currents of the distribution transformers with measured load records. max ; Step 3.25: Determine the maximum current on the high-voltage side of the distribution transformer without measured load records: The sum of the maximum currents of the distribution transformer without measured load records I B∑ , is the maximum current I′ at the first end max Subtract the sum of the maximum current of the high-voltage user and the maximum current of the distribution transformer with measured current records I max∑ , that is: I B∑ =I′ max -I max∑ , after allocating the capacity of each distribution transformer without measured load, the maximum current of each transformer can be obtained: Among them, I BKm is the maximum current of the Kth distribution transformer without measured load record; I B ∑ is the sum of the maximum currents of the distribution transformers without measured load records; S∑ is the total capacity of the distribution transformers without measured load records; S eK The rated capacity of the Kth distribution transformer without actual load measurement record; Step 3.26: Calculate the equivalent resistance of the line: The loss generated when the maximum current at the head end of the line passes through the equivalent resistance should be exactly equal to the loss generated when each line runs at the actual maximum current in the same time period, that is, the equivalent resistance is: Among them, R d is the equivalent resistance of the line; R k is the resistance of the kth line; I max,k is the maximum current of the kth line; I′ max is the maximum current at the first end after correction; Step 3.27: Calculate the line power loss within time t: Step 3.28: Calculate the power losses of the distribution transformer: Fixed losses: Among them, ΔP oi is the short-circuit loss of the i-th transformer.

9. The main network line loss analysis and calculation method based on VBA as claimed in claim 1, characterized in that: The construction of the VBA-based gateway model in step 4 specifically includes the following steps: Step 4.1: Analyze the main grid component model structure, classify and summarize the components, optimize them using VBA, use component names, switches, metering points, calculation relationships, and key information of calculated electricity, use different color areas to represent the input and output metering points of the component model, refer to the metering point exchange records of the integrated electricity and line loss system, convert the updated meter exchange records into the electricity of the same period and include them in the metering points, and finally generate the metering point electricity calculation; Step 4.2: Use a VBA-based user form to display the component line loss rate, and use vsFlexGrid to distinguish the line loss rate of all components from the components with excessive line loss rate; Step 4.3: According to the control mechanism of the whitelist of line loss rate of main grid components, the whitelist is verified, and the components that still do not meet the line loss rate requirements are specially marked. Finally, the line loss rate of the entire region during the same period is generated for reference.

10. The main network line loss analysis and calculation method based on VBA as claimed in claim 1, characterized in that: The step 5 of using the XLAM loading module started with the gateway model to provide a one-stop reference calculation service for the line loss of the regional main grid components specifically includes the following steps: Step 5.1: Use the Excel-based real-time loading module to perform power and line loss statistical analysis on the gateway model at any time; Step 5.2: As the gateway model is started, the analysis and statistics tool module is automatically loaded, which improves work efficiency and is deeply integrated into the Excel tool module; Step 5.3: Integrate the display mode of the component model, use a separate line loss dedicated tool module, create a line loss calculation form, associate the table change records, format the line loss table, analyze the system power, and provide a one-stop reference measurement service for the regional main network component line loss, effectively improving the regional main network line loss rate.

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