Multi-dimensional low-voltage transformer area theoretical line loss prediction method

Abstract

The invention discloses a multi-dimensional low-voltage transformer area theoretical line loss prediction method, which comprises the following steps of: acquiring and calculating a three-phase loop impedance and three-phase current N-point curve data matrix by using electricity acquisition equipment, and calculating live line impedance values and zero line impedance values of an electric meter, a meter box and a branch node; calculating to obtain a zero line daily current square N point curve data matrix; and calculating the theoretical line loss of the current low-voltage transformer area, wherein the theoretical line loss comprises all electric meter fixed theoretical loss, all meter front theoretical line loss, all meter box-to-branch theoretical line loss and all branch-to-transformer theoretical line loss. According to the multi-dimensional low-voltage transformer area theoretical line loss prediction method, multi-dimensional data is adopted, so that the theoretical line loss prediction precision is effectively improved; different data qualities can be effectively adapted, and the adaptability is high; the theoretical impedance of each section of line in the low-voltage transformer area can be calculated in a segmented manner, and more refined line loss problem analysis is realized.

Description

Technical Field

[0001] The invention relates to a multi-dimensional low-voltage substation theoretical line loss prediction method, belonging to the technical field of low-voltage substations. Background Art

[0002] Line loss refers to the loss of electricity in the power network, which consists of theoretical line loss and management line loss. Among them, management line loss is caused by metering errors, poor management and other reasons; while theoretical line loss is the normal loss of the power grid in the process of transmitting and distributing electric energy. The calculation of the theoretical line loss value of the low-voltage substation can provide a theoretical basis for the formulation of the substation loss reduction index to improve the economic benefits of the power grid operation. At present, the commonly used methods for calculating the theoretical line loss of low-voltage substations include the power flow method, the equivalent resistance method, the voltage loss method and big data machine learning.

[0003] However, these methods have some limitations and problems. The power flow method and voltage loss method have high requirements on data quality and large deviations in the accuracy of the results. In particular, the big data machine learning method has problems such as insufficient data collection and overfitting of the model, which may lead to inaccurate calculation of theoretical line loss.

[0004] Therefore, a new multi-dimensional low-voltage area theoretical line loss prediction method is needed to solve the above problems. Summary of the invention

[0005] Purpose of the invention: In view of the problems existing in the prior art, the present invention provides a multi-dimensional low-voltage area theoretical line loss prediction method.

[0006] A multi-dimensional low-voltage area theoretical line loss prediction method, wherein the low-voltage area has m electric meters, n meter boxes and o branch nodes, comprises the following steps:

[0007] Step 1: Use power collection equipment to collect three-phase loop impedance, which includes the three-phase loop impedance from each meter to its upper meter box, the three-phase loop impedance from each meter box to its upper branch node, and the three-phase loop impedance from each branch node to its upper transformer;

[0008] The three-phase current N-point curve data matrix is ​​obtained by using the power collection device, wherein the three-phase current N-point curve data matrix includes the daily three-phase current N-point curve data matrix of each electric meter, the daily three-phase current N-point curve data matrix of each meter box and the daily three-phase current N-point curve data matrix of each branch node;

[0009] Step 2: According to the three-phase loop impedance and the three-phase current N-point curve data matrix obtained in step 1, the live line impedance value and the neutral line impedance value of the m electric meters, the live line impedance value and the neutral line impedance value of the n meter boxes and the live line impedance value and the neutral line impedance value of the o branch nodes are calculated;

[0010] Step 3: Calculate and obtain a zero line daily current square N-point curve data matrix, wherein the zero line daily current square N-point curve data matrix includes the zero line daily current square N-point curve data matrix of m electric meters, the zero line daily current square N-point curve data matrix of n meter boxes, and the zero line daily current square N-point curve data matrix of o branch nodes;

[0011] Step 4: Calculate the theoretical line loss of the current low-voltage area, including the fixed theoretical loss of all meters, the theoretical line loss before all meters, the theoretical line loss from all meter boxes to branches, and the theoretical line loss from all branches to transformers.

[0012] Furthermore, the three-phase loop impedance from each electric meter to its upper meter box in step 1 is expressed by the following formula:

[0013]

[0014] In the formula, represents the A-phase loop impedance of meter m, represents the B-phase loop impedance of meter m, It represents the C-phase loop impedance of the electric meter m;

[0015] The three-phase loop impedance from each meter box to its upper branch node is expressed by the following formula:

[0016]

[0017] In the formula, Indicates the A-phase loop impedance of meter box n, Indicates the B-phase loop impedance of meter box n, Indicates the C-phase loop impedance of meter box n;

[0018] The three-phase loop impedance from each branch node to its upstream transformer is expressed by the following formula:

[0019]

[0020] In the formula, represents the A-phase loop impedance of branch o, represents the B-phase loop impedance of branch o, Indicates the C-phase loop impedance of branch o.

[0021] Furthermore, the daily three-phase current N-point curve data matrix of each electric meter in step 1 is expressed by the following formula:

[0022]

[0023] In the formula, It represents the value of the Nth point in the A-phase current curve of the meter m, represents the value of the Nth point in the B-phase current curve of meter m, It represents the value of the Nth point in the C-phase current curve of the meter m, I SMeterA Represents the matrix of all current curves of phase A meters, I SMeterB represents the matrix of all current curves of phase B meters, I SMeterC Represents the matrix of the current curves of all the electric meters of phase C;

[0024] The daily three-phase current N-point curve data matrix of each meter box is expressed by the following formula:

[0025]

[0026] In the formula, Indicates the value of the Nth point in the A-phase current curve of meter box n, Indicates the value of the Nth point in the B-phase current curve of meter box n, Indicates the value of the Nth point in the C-phase current curve of meter box n, I SMeterboxA Represents the matrix of all current curves of the meter boxes of phase A, I SMeterboxB represents the matrix of all current curves of the meter boxes in phase B, I SMeterboxC Represents the matrix of the current curves of all meter boxes of phase C;

[0027] The daily three-phase current N-point curve data matrix of each branch node is expressed by the following formula:

[0028]

[0029] In the formula, represents the value of the Nth point in the A-phase current curve of branch o, represents the value of the Nth point in the B-phase current curve of branch o, Indicates the value of the Nth point in the C-phase current curve of branch o, I SBranchA represents the matrix of all branch current curves of phase A, I SBranchB represents the matrix of all branch current curves of phase B, I SBranchC Represents the collection matrix of all branch current curves of phase C.

[0030] Furthermore, the live line impedance value and the neutral line impedance value of the m electric meters in step 2 are expressed by the following formula:

[0031]

[0032]

[0033]

[0034]

[0035] In the formula, It represents the A-phase live wire impedance of the meter m, represents the B-phase live wire impedance of meter m, represents the C-phase live wire impedance of the meter m, represents the zero line impedance of the meter m, represents the A-phase loop impedance of meter m, represents the B-phase loop impedance of meter m, It represents the C-phase loop impedance of meter m; the live wire impedance value and neutral wire impedance value of n meter boxes are expressed by the following formula:

[0036]

[0037] In the formula, Indicates the A-phase live wire impedance of meter box n, It represents the B phase live wire impedance of meter box n, It represents the C phase live wire impedance of meter box n, Indicates the zero line impedance of the meter box n, Indicates the A-phase loop impedance of meter box n, Indicates the B-phase loop impedance of meter box n, Indicates the C-phase loop impedance of meter box n;

[0038] The live line impedance value and the neutral line impedance value of o branch nodes are expressed by the following formula:

[0039]

[0040] In the formula, It represents the A phase live line impedance of branch o, represents the B phase live line impedance of branch o, represents the C phase live line impedance of branch o, represents the neutral line impedance of branch o, represents the A-phase loop impedance of branch o, represents the B-phase loop impedance of branch o, Indicates the C-phase loop impedance of branch o.

[0041] Furthermore, in step three

[0042] The data matrix of the daily square N-point curve of the neutral line current of m meters is expressed by the following formula:

[0043]

[0044] In the formula, It represents the square of the Nth point of the zero-line current curve of the meter m, It represents the value of the Nth point in the A-phase current curve of the meter m, represents the value of the Nth point in the B-phase current curve of meter m, It represents the value of the Nth point in the C-phase current curve of the meter m;

[0045] The data matrix of the daily square N-point curve of the neutral line current of n meter boxes is expressed by the following formula:

[0046]

[0047] In the formula, It represents the square of the Nth point of the zero line current curve of the meter box n, Indicates the value of the Nth point in the A-phase current curve of meter box n, Indicates the value of the Nth point in the B-phase current curve of meter box n, It represents the value of the Nth point in the C-phase current curve of meter box n;

[0048] The data matrix of the daily current square N-point curve of the zero line of o branch nodes is expressed by the following formula:

[0049]

[0050] In the formula, Represents the square of the Nth point of the branch o neutral current curve, represents the value of the Nth point in the A-phase current curve of branch o, represents the value of the Nth point in the B-phase current curve of branch o, Represents the value of the Nth point in the C-phase current curve of branch o.

[0051] Furthermore, the theoretical line loss of the current low-voltage area in step 4 is calculated by the following formula:

[0052] W P =W Meter +W MeterLine +W MeterboxLine +W BranchLine

[0053] Where W Meter Represents the fixed theoretical loss of all meters, W MeterLine Represents all theoretical line losses before the meter, W MeterboxLine Indicates the theoretical line loss from all meter boxes to branches, W BranchLine Represents the theoretical line loss from all branches to the transformer.

[0054] Furthermore, in step 4,

[0055] All electric meters have fixed theoretical losses W Meter Calculated by the following formula:

[0056] W Meter =PMeter ×24×m

[0057] Where P Meter represents the fixed power loss of the electric meter, and m represents the number of electric meters;

[0058] All theoretical line losses before the meter W MeterLine Calculated by the following formula:

[0059]

[0060] In the formula, is the A-phase live wire impedance of meter i, is the B-phase live wire impedance of meter i, is the C-phase live wire impedance of meter i, is the zero-sequence impedance of meter i, is the current value of the jth point of the A phase current curve of meter i, is the current value of the jth point of the B-phase current curve of meter i, is the current value of the jth point of the C-phase current curve of meter i, is the current value of the jth point of the zero-sequence current curve of meter i, and X is the number of points of the current curve collected daily;

[0061] Theoretical line loss from all meter boxes to branches W MeterboxLine Calculated by the following formula:

[0062]

[0063] In the formula, is the A-phase live wire impedance of meter i, is the B-phase live wire impedance of meter i, is the C-phase live wire impedance of meter i, is the zero-sequence impedance of meter i, is the current value of the jth point of the A phase current curve of meter i, is the current value of the jth point of the B-phase current curve of meter i, is the current value of the jth point of the C-phase current curve of meter i, is the current value of the jth point of the zero-sequence current curve of meter i, and X is the number of points of the current curve collected daily;

[0064] Theoretical line loss from all branches to transformer W BranchLine Calculated by the following formula:

[0065]

[0066] In the formula, is the A-phase live wire impedance of meter i, is the B-phase live wire impedance of meter i, is the C-phase live wire impedance of meter i, is the zero-sequence impedance of meter i, is the current value of the jth point of the A phase current curve of meter i, is the current value of the jth point of the B-phase current curve of meter i, is the current value of the jth point of the C-phase current curve of meter i, is the current value of the jth point of the zero-sequence current curve of meter i, and X is the number of points of the current curve collected daily.

[0067] Furthermore, X is 1440.

[0068] Beneficial effects: The multi-dimensional low-voltage substation theoretical line loss prediction method of the present invention adopts multi-dimensional data to effectively improve the accuracy of theoretical line loss prediction; it can effectively adapt to different data qualities and has strong adaptability; it can calculate the theoretical impedance of each section of the low-voltage substation line in sections, and realize more refined line loss problem analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 This is a flow chart for calculating theoretical line loss based on multi-dimensional low-voltage areas. DETAILED DESCRIPTION

[0070] The preferred embodiments of the present invention will be described below in conjunction with the accompanying drawings to more clearly and completely illustrate the technical solutions of the present invention.

[0071] Example 1

[0072] See also Figure 1 As shown, taking the theoretical line loss calculation process of a certain transformer area as an example, the technical solution of the present invention is explained in detail.

[0073] The multi-dimensional low-voltage area theoretical line loss prediction method of the present invention comprises the following steps:

[0074] Step 1: Use power collection equipment to collect and calculate the three-phase loop impedance from each meter to its upper meter box

[0075]

[0076] The three-phase loop impedance from each meter box to its upper branch node

[0077]

[0078] The three-phase loop impedance from each branch node to its upstream transformer

[0079]

[0080] Step 2: Use power consumption collection equipment to obtain the daily minute-level three-phase current curve matrix of each meter:

[0081] Daily minute-level three-phase current curve matrix for each meter box:

[0082]

[0083] Daily minute-level three-phase current curve matrix for each branch node:

[0084]

[0085] Step 3: According to the formula

[0086]

[0087] The live wire impedance value of meter 1 is calculated.

[0088] Step 4: According to the formula

[0089]

[0090] The zero line impedance value of meter 1 is calculated.

[0091] Step 5: Repeat steps 3 to 4 to calculate the live wire impedance value of meter 2-meter m And the neutral line impedance value

[0092] Step 6: Repeat steps 3 to 5 to calculate the live wire impedance value of meter box 1 to meter box n And the neutral line impedance value

[0093] Step 7: Repeat steps 3 to 5 to calculate the live wire impedance value of branch 1-branch o And the neutral line impedance value

[0094] Step 8: According to the formula

[0095]

[0096] Calculate the daily minute-level curve matrix of the neutral current square of meter k

[0097] Step 9: Repeat step 8 to obtain the square daily minute-level curve matrix of the meter box neutral current. And branch neutral current square daily minute level curve matrix

[0098] Step 10: The fixed power loss of the electric meter is P Meter , according to the formula

[0099] W Meter =P Meter ×24×m

[0100] Calculate the fixed theoretical loss W of all electric meters in the area Meter .

[0101] Step 11: According to the formula

[0102]

[0103] The sum of theoretical line losses before all meters in the substation area is calculated as W MeterLine .

[0104] Step 12: Repeat step 11 to calculate the sum of the theoretical line losses from all meter boxes to branches in the substation area, W MeterboxLine And the sum of the theoretical line losses of all branches to the transformer W BranchLine .

[0105] Step 13: According to the formula

[0106] W P =W Meter +W MeterLine +W MeterboxLine +W BranchLine

[0107] The theoretical line loss of the area on that day was calculated to be 18.67kWh. The total power of the area on that day was 1052.31kWh, and the statistical line loss on that day was 25.77kWh. The theoretical line loss rate was 1.77%, and the statistical line loss rate was 2.45%. The difference between the theoretical line loss and the statistical line loss was within 1%, indicating that the line loss in this area was normal.

Claims

1. A multi-dimensional low voltage area theoretical line loss prediction method, characterized in that: The low voltage area has m meters, n meter boxes and o branch nodes, including the following steps: Step 1: Use power collection equipment to collect three-phase loop impedance, which includes the three-phase loop impedance from each meter to its upper meter box, the three-phase loop impedance from each meter box to its upper branch node, and the three-phase loop impedance from each branch node to its upper transformer; The three-phase current N-point curve data matrix is ​​obtained by using the power collection device, wherein the three-phase current N-point curve data matrix includes the daily three-phase current N-point curve data matrix of each electric meter, the daily three-phase current N-point curve data matrix of each meter box and the daily three-phase current N-point curve data matrix of each branch node; Step 2: According to the three-phase loop impedance and the three-phase current N-point curve data matrix obtained in step 1, the live line impedance value and the neutral line impedance value of the m electric meters, the live line impedance value and the neutral line impedance value of the n meter boxes and the live line impedance value and the neutral line impedance value of the o branch nodes are calculated; Step 3: Calculate and obtain a zero line daily current square N-point curve data matrix, wherein the zero line daily current square N-point curve data matrix includes the zero line daily current square N-point curve data matrix of m electric meters, the zero line daily current square N-point curve data matrix of n meter boxes, and the zero line daily current square N-point curve data matrix of o branch nodes; Step 4: Calculate the theoretical line loss of the current low-voltage area, including the fixed theoretical loss of all meters, the theoretical line loss before all meters, the theoretical line loss from all meter boxes to branches, and the theoretical line loss from all branches to transformers.

2. The multi-dimensional low voltage area theoretical line loss prediction method according to claim 1, characterized in that: In step 1, the three-phase loop impedance from each meter to its upper meter box is expressed by the following formula: In the formula, represents the A-phase loop impedance of meter m, represents the B-phase loop impedance of meter m, It represents the C-phase loop impedance of the electric meter m; The three-phase loop impedance from each meter box to its upper branch node is expressed by the following formula: In the formula, Indicates the A-phase loop impedance of meter box n, Indicates the B-phase loop impedance of meter box n, Indicates the C-phase loop impedance of meter box n; The three-phase loop impedance from each branch node to its upstream transformer is expressed by the following formula: In the formula, represents the A-phase loop impedance of branch o, represents the B-phase loop impedance of branch o, Indicates the C-phase loop impedance of branch o.

3. The multi-dimensional low voltage area theoretical line loss prediction method according to claim 1, characterized in that: The daily three-phase current N-point curve data matrix of each electric meter in step 1 is expressed by the following formula: In the formula, It represents the value of the Nth point in the A-phase current curve of the meter m, represents the value of the Nth point in the B-phase current curve of meter m, It represents the value of the Nth point in the C-phase current curve of the meter m, I SMeterA Represents the matrix of all current curves of phase A meters, I SMeterB represents the matrix of all current curves of phase B meters, I SMeterC Represents the matrix of the current curves of all the electric meters of phase C; The daily three-phase current N-point curve data matrix of each meter box is expressed by the following formula: In the formula, Indicates the value of the Nth point in the A-phase current curve of meter box n, Indicates the value of the Nth point in the B-phase current curve of meter box n, Indicates the value of the Nth point in the C-phase current curve of meter box n, I SMeterboxA Represents the matrix of all current curves of the meter boxes of phase A, I SMeterboxB represents the matrix of all current curves of the meter boxes in phase B, I SMeterboxC Represents the matrix of the current curves of all meter boxes of phase C; The daily three-phase current N-point curve data matrix of each branch node is expressed by the following formula: In the formula, represents the value of the Nth point in the A-phase current curve of branch o, represents the value of the Nth point in the B-phase current curve of branch o, Indicates the value of the Nth point in the C-phase current curve of branch o, I SBranchA represents the matrix of all branch current curves of phase A, I SBranchB represents the matrix of all branch current curves of phase B, I SBranchC Represents the collection matrix of all branch current curves of phase C.

4. The multi-dimensional low voltage area theoretical line loss prediction method according to claim 1, characterized in that: In step 2, the live line impedance value and the neutral line impedance value of the m electric meters are expressed by the following formula: In the formula, It represents the A-phase live wire impedance of the meter m, It represents the B-phase live wire impedance of the meter m, represents the C-phase live wire impedance of the meter m, represents the zero line impedance of the meter m, represents the A-phase loop impedance of meter m, represents the B-phase loop impedance of meter m, It represents the C-phase loop impedance of meter m; the live wire impedance value and neutral wire impedance value of n meter boxes are expressed by the following formula: In the formula, Indicates the A-phase live wire impedance of meter box n, It represents the B phase live wire impedance of meter box n, It represents the C phase live wire impedance of meter box n, Indicates the zero line impedance of the meter box n, Indicates the A-phase loop impedance of meter box n, Indicates the B-phase loop impedance of meter box n, Indicates the C-phase loop impedance of meter box n; The live line impedance value and the neutral line impedance value of o branch nodes are expressed by the following formula: In the formula, It represents the A phase live line impedance of branch o, represents the B phase live line impedance of branch o, represents the C phase live line impedance of branch o, represents the neutral line impedance of branch o, represents the A-phase loop impedance of branch o, represents the B-phase loop impedance of branch o, Indicates the C-phase loop impedance of branch o.

5. The multi-dimensional low voltage area theoretical line loss prediction method according to claim 1, characterized in that: The data matrix of the daily square N-point curve of the neutral line current of m meters in step 3 is expressed by the following formula: In the formula, It represents the square of the Nth point of the zero-line current curve of the meter m, It represents the value of the Nth point in the A-phase current curve of the meter m, represents the value of the Nth point in the B-phase current curve of meter m, It represents the value of the Nth point in the C-phase current curve of the meter m; The data matrix of the daily square N-point curve of the neutral line current of n meter boxes is expressed by the following formula: In the formula, It represents the square of the Nth point of the zero line current curve of the meter box n, Indicates the value of the Nth point in the A-phase current curve of meter box n, Indicates the value of the Nth point in the B-phase current curve of meter box n, It represents the value of the Nth point in the C-phase current curve of meter box n; The data matrix of the daily current square N-point curve of the zero line of o branch nodes is expressed by the following formula: In the formula, Represents the square of the Nth point of the branch o neutral current curve, represents the value of the Nth point in the A-phase current curve of branch o, represents the value of the Nth point in the B-phase current curve of branch o, Represents the value of the Nth point in the C-phase current curve of branch o.

6. The multi-dimensional low voltage area theoretical line loss prediction method according to claim 1, characterized in that: In step 4, the theoretical line loss of the current low-voltage area is calculated by the following formula: IN P =In Meter +W MeterLine +W MeterboxLine +W BranchLine Where W Meter Represents the fixed theoretical loss of all meters, W MeterLine Represents all theoretical line losses before the meter, W MeterboxLine Indicates the theoretical line loss from all meter boxes to branches, W BranchLine Represents the theoretical line loss from all branches to the transformer.

7. The multi-dimensional low voltage area theoretical line loss prediction method according to claim 1, characterized in that: In step 4, all meters have a fixed theoretical loss W Meter Calculated by the following formula: W Meter =P Meter ×24×m Where P Meter represents the fixed power loss of the electric meter, and m represents the number of electric meters; All theoretical line losses before the meter W MeterLine Calculated by the following formula: In the formula, is the A-phase live wire impedance of meter i, is the B-phase live wire impedance of meter i, is the C-phase live wire impedance of meter i, is the zero-sequence impedance of meter i, is the current value of the jth point of the A phase current curve of meter i, is the current value of the jth point of the B-phase current curve of meter i, is the current value of the jth point of the C-phase current curve of meter i, is the current value of the jth point of the zero-sequence current curve of meter i, and X is the number of points of the current curve collected daily; Theoretical line loss from all meter boxes to branches W MeterboxLine Calculated by the following formula: In the formula, is the A-phase live wire impedance of meter i, is the B-phase live wire impedance of meter i, is the C-phase live wire impedance of meter i, is the zero-sequence impedance of meter i, is the current value of the jth point of the A phase current curve of meter i, is the current value of the jth point of the B-phase current curve of meter i, is the current value of the jth point of the C-phase current curve of meter i, is the current value of the jth point of the zero-sequence current curve of meter i, and X is the number of points of the current curve collected daily; Theoretical line loss from all branches to transformer W BranchLine Calculated by the following formula: In the formula, is the A-phase live wire impedance of meter i, is the B-phase live wire impedance of meter i, is the C-phase live wire impedance of meter i, is the zero-sequence impedance of meter i, is the current value of the jth point of the A phase current curve of meter i, is the current value of the jth point of the B-phase current curve of meter i, is the current value of the jth point of the C-phase current curve of meter i, is the current value of the jth point of the zero-sequence current curve of meter i, and X is the number of points of the current curve collected daily.

8. The multi-dimensional low voltage area theoretical line loss prediction method according to claim 7, characterized in that: X is 1440.

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