A precise investment calculation method for distribution network planning projects

Abstract

The present invention provides a method for calculating precise investment in a distribution network planning project, comprising the following steps: (1) collecting basic information of each line in a target area through a power grid database platform, excluding user dedicated lines, lines with large line loss deviations, and spare lines, obtaining sample lines, and calculating the cost of line loss per unit load moment; (2) obtaining sample information of power shortage of users in the target area through a questionnaire, classifying the sample information of power shortage according to the industry to which the users belong, and calculating the cost of power shortage in the target area. The present invention quantifies the power shortage and the line loss cost in the same period by calculating the cost of line loss per unit load moment in the target area and the cost of power shortage in the target area, so that power grid enterprises can conduct evaluation and selection, and provide a basis for precise investment in distribution network planning.

Description

Technical Field

[0001] The present invention relates to the field of electric power technology, and in particular to a method for calculating accurate investment in a distribution network planning project. Background Art

[0002] my country's power distribution network has many nodes, branch lines and components. With the sustained and stable growth of my country's economy and the transformation and development of energy, the investment in distribution network construction continues to increase. It is of great significance to improve the precision of investment in distribution networks.

[0003] For users who receive power services, voltage qualification rate, synchronous line loss and power supply reliability are the most basic service requirements. The investment planning of power grid enterprises must start from the above service requirements and formulate investment and construction plans. The voltage qualification rate is a national mandatory power supply quality standard and does not require cost quantification. At present, there is a lack of cost quantification of synchronous line loss and power shortage, which leads to the lack of investment demand assessment for power grid enterprises and makes it difficult to achieve accurate investment in distribution network planning. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a method for calculating the precise investment of a distribution network planning project, comprising the following steps:

[0005] (1) Collect basic information of each line in the target area through the power grid database platform, exclude user-specific lines, lines with large line loss deviations, and spare lines, obtain sample lines, and calculate the cost of line loss electricity per unit load moment;

[0006] (2) Obtain power shortage sample information of users in the target area through questionnaires, classify the power shortage sample information according to the industry to which the users belong, and calculate the power shortage cost of the target area.

[0007] Furthermore, the cost of calculating the annual line loss electricity per unit load moment in step (1) includes the following steps:

[0008] (a) Calculate the equivalent line loss power, annual utilization hours, and equivalent load moment of each line in the sample line;

[0009] (b) calculating the unit load moment annual line loss electricity of each line in the sample line, and calculating the average unit load moment annual line loss electricity of the sample line based on the unit load moment annual line loss electricity of each line;

[0010] (c) Calculate the cost of line loss per unit load moment based on the average annual line loss per unit load moment of the sample line and the purchase cost per kilowatt-hour.

[0011] Furthermore, the power grid database platform includes PMS2.0 system, EMS system, DMS system, PIS2.0 system, and synchronous line loss system; the basic information includes line name, line nature, line length, line impedance, proportion of public and private transformers, number of distribution transformers and corresponding rated capacity of distribution transformers, daily power supply, daily line loss, monthly power supply, monthly line loss, and annual cumulative power supply.

[0012] Furthermore, the equivalent line loss power P of the i-th line in the sample line Ei The calculation formula is:

[0013]

[0014] Where, ΔE ij is the daily line loss of the i-th line on the j-th day, E ij is the daily power supply of the i-th line on the j-th day, P ij is the rated capacity of one of the distribution transformers on the i-th line on the j-th day, and m is the number of lines in the sample line;

[0015] The annual utilization hours H of the i-th line in the sample line Ui The calculation formula is:

[0016]

[0017] Where E is the annual cumulative power supply of the ith line, P ik is the rated capacity of the kth distribution transformer on the i-th line, and n is the number of distribution transformers installed on the i-th line;

[0018] The equivalent load moment P of the i-th line in the sample line Li The calculation formula is:

[0019]

[0020] Among them, Z i is the impedance of the ith line, Z iN is the reference impedance, L i is the length of the ith line, K is the weight coefficient, and its expression is as follows:

[0021]

[0022] Furthermore, the unit load moment annual line loss of the i-th line in the sample line is ΔE Li The calculation formula is:

[0023]

[0024] The average unit load moment annual line loss of m lines in the sample line is ΔEL The calculation formula is:

[0025]

[0026] Furthermore, the cost of annual line loss per unit load moment C U The calculation formula is:

[0027] C U =C×ΔE L

[0028] Among them, C is the purchase cost per kilowatt-hour.

[0029] Furthermore, calculating the power shortage cost of the target area in step (2) includes the following steps:

[0030] (d) Calculate the reliability power loss cost and power shortage cost for each user in each industry at different power outage durations;

[0031] (e) The weighted average method is used to calculate the power outage cost of each industry under different power outage durations, and a discrete sample of the power outage cost of each industry is obtained;

[0032] (f) Linear regression method is used to transform the discrete samples of power outage costs of various industries into linear functions with power outage time as the independent variable;

[0033] (g) The power shortage cost of each industry is adjusted using the weight coefficient to calculate the power shortage cost of the target area.

[0034] Furthermore, the power shortage sample information of the user includes the user's annual power consumption, the user's annual power consumption hours, and the estimated cost loss of the user corresponding to different power outage durations.

[0035] Furthermore, the reliability power loss cost P corresponding to the power outage duration k hours for user j in industry i is ijk The calculation formula is:

[0036]

[0037] Among them, i=1 represents a bank data center, i=2 represents a commercial center, i=3 represents an industrial and commercial outlet, i=4 represents a restaurant, i=5 represents a mechanical processing center, and i=6 represents a resident; C ijk E is the estimated cost loss of user j in industry i when the power outage lasts k hours; ij is the annual electricity consumption of user j in industry i during a statistical period of one year; H ij h is the annual electricity consumption hours of user j in industry i during a statistical period of one year;

[0038] The power shortage cost RC corresponding to the power outage duration k hours for user j in industry i ijk The calculation formula is:

[0039]

[0040] Among them, k is the duration of power outage;

[0041] The power shortage cost R corresponding to the power outage duration k hours in industry i ik The calculation formula is:

[0042]

[0043] Where n is the number of users of the questionnaire in industry i.

[0044] Furthermore, the power shortage cost R corresponding to the power outage duration k hours for industry i is ik The linear function expression is:

[0045] R ik = k × R in +R i0 ;

[0046] The calculation formula of the power shortage cost R in the target area is:

[0047]

[0048] Among them, β i is the weight coefficient of industry i, and its calculation formula is:

[0049]

[0050] Among them, GDP i is the annual GDP output value of industry i in the target area, E i is the annual electricity consumption of industry i in the target area, GDP T is the annual GDP output value in the target area, E T is the annual electricity consumption in the target area.

[0051] The present invention quantifies the power shortage and the line loss cost in the same period by calculating the cost of annual line loss electricity per unit load moment in the target area and the power shortage cost in the target area, so as to facilitate evaluation and selection by power grid companies and provide a basis for precise investment in distribution network planning. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a flow chart of a method for quantifying the cost of synchronous line losses in a distribution network based on load moments provided by the present invention;

[0053] Figure 2It is a flow chart of the method for quantifying the cost of power shortage in distribution network provided by the present invention. DETAILED DESCRIPTION

[0054] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0055] like Figure 1 , Figure 2 As shown, the present invention provides a method for calculating accurate investment in a distribution network planning project, comprising the following steps:

[0056] (1) Collect basic information of each line in the target area through the power grid database platform, exclude user-specific lines, lines with large line loss deviations, and spare lines, obtain sample lines, and calculate the cost of line loss electricity per unit load moment;

[0057] (2) Obtain power shortage sample information of users in the target area through questionnaires, classify the power shortage sample information according to the industry to which the users belong, and calculate the power shortage cost of the target area.

[0058] Furthermore, the cost of calculating the annual line loss electricity per unit load moment in step (1) includes the following steps:

[0059] (a) Calculate the equivalent line loss power, annual utilization hours, and equivalent load moment of each line in the sample line;

[0060] (b) calculating the unit load moment annual line loss electricity of each line in the sample line, and calculating the average unit load moment annual line loss electricity of the sample line based on the unit load moment annual line loss electricity of each line;

[0061] (c) Calculate the cost of line loss per unit load moment based on the average annual line loss per unit load moment of the sample line and the purchase cost per kilowatt-hour.

[0062] The power grid database platform includes PMS2.0 system, EMS system, DMS system, PIS2.0 system, and synchronous line loss system; the basic information includes line name, line nature, line length, line impedance, proportion of public and private transformers, number of distribution transformers and corresponding distribution transformer rated capacity, daily power supply, daily line loss power, monthly power supply, monthly line loss power, and annual cumulative power supply. User dedicated lines and backup lines can be known from the line nature. The method for determining lines with large line loss deviations is: a. Calculate the monthly line loss rate of each line in the target area in each month during the one-year statistical period. If the monthly line loss rate is higher than the index requirement value, it is determined to be a high-loss line. If the monthly line loss rate is less than 0%, it is determined to be a negative loss line; b. If a line is determined to be one of a high-line loss line and a negative loss line for more than 3 consecutive months within the one-year statistical period or for 5 months within the one-year statistical period, the line is determined to be a line with a large line loss deviation. Lines with large line loss deviations often have problems such as incorrect station-user relationships or measurement equipment failures, and are not suitable as credible samples.

[0063] The equivalent line loss power P of the i-th line in the sample line Ei The calculation formula is:

[0064]

[0065] Where, ΔE ij is the daily line loss of the i-th line on the j-th day, E ij is the daily power supply of the i-th line on the j-th day, P ij is the rated capacity of one of the distribution transformers on the i-th line on the j-th day, and m is the number of lines in the sample line. It can be understood that since the statistical period is one year, the value of j ranges from 1 to 365. When there are 49 lines in the sample line, m = 49. Of course, m can also be other values, depending on the number of lines in the sample line. There are multiple distribution transformers installed along the length of the i-th line, and P ij It is the rated capacity of any distribution transformer among multiple distribution transformers.

[0066] The annual utilization hours H of the i-th line in the sample line Ui The calculation formula is:

[0067]

[0068] Where E is the annual cumulative power supply of the ith line, P ik is the rated capacity of the kth distribution transformer on the i-th line, n is the number of distribution transformers installed on the i-th line, and m is the number of lines in the sample line;

[0069] The equivalent load moment P of the i-th line in the sample line Li The calculation formula is:

[0070]

[0071] Among them, Z i is the impedance of the ith line, Z iN is the reference impedance, L i is the length of the ith line, P ik is the rated capacity of the kth distribution transformer on the i-th line, n is the number of distribution transformers installed on the i-th line, m is the number of lines in the sample line, and Z iN The impedance value corresponding to the 10KV cable model ZRYJV22-3×400 can be selected. K is the weight coefficient, and its expression is as follows:

[0072]

[0073] Unit load moment annual line loss ΔE of the i-th line in the sample line Li The calculation formula is:

[0074]

[0075] The average unit load moment annual line loss of m lines in the sample line is ΔE L The calculation formula is:

[0076]

[0077] The cost of annual line loss electricity per unit load moment C U The calculation formula is:

[0078] C U =C×ΔE L

[0079] Among them, C is the purchase cost per kilowatt-hour of electricity.

[0080] Furthermore, calculating the power shortage cost of the target area in step (2) includes the following steps:

[0081] (d) Calculate the reliability power loss cost and power shortage cost for each user in each industry at different power outage durations;

[0082] (e) The weighted average method is used to calculate the power outage cost of each industry under different power outage durations, and a discrete sample of the power outage cost of each industry is obtained;

[0083] (f) The linear regression method is used to transform the discrete samples of power outage costs in various industries into linear functions with power outage time as the independent variable;

[0084] (g) The power shortage cost of each industry is adjusted using the weight coefficient to calculate the power shortage cost of the target area.

[0085] The number of questionnaires for each industry can be 15 to 20, and the power used by users in each industry should be as similar as possible. When the power used by users in the same industry in the collected questionnaires varies greatly, they can be further classified within the industry so that the power used by users in each industry after classification is similar. The user's power shortage sample information includes the user's annual power consumption, the user's annual power consumption hours, and the user's cost loss estimate corresponding to different power outage durations. Industries include bank data centers, commercial centers, industrial and commercial outlets, catering, mechanical processing, and residents.

[0086] The reliability power loss cost P corresponding to the power outage duration k hours for the j user in the i industry in the questionnaire ijk The calculation formula is:

[0087]

[0088] Among them, i=1 represents a bank data center, i=2 represents a commercial center, i=3 represents an industrial and commercial outlet, i=4 represents a restaurant, i=5 represents a mechanical processing center, and i=6 represents a resident; C ijk E is the estimated cost loss of user j in industry i when the power outage lasts k hours, in yuan; ij is the annual electricity consumption of user j in industry i during a statistical period of one year, in kWh; H ij is the annual electricity consumption hours of user j in industry i during the statistical period of one year, in h; k can be 0, 1, 2, 3, etc. When k is 0, it indicates an instantaneous power outage.

[0089] The power outage cost RC corresponding to the power outage duration k hours for the j user in the i industry in the questionnaire ijk The calculation formula is:

[0090]

[0091] Where k is the duration of the power outage.

[0092] The power outage cost R corresponding to the power outage duration k hours for industry i in the questionnaire ik The calculation formula is:

[0093]

[0094] Where n is the number of users of the questionnaire in industry i, R ik is a discrete function of time k.

[0095] The power outage cost R corresponding to the power outage duration k hours in industry i in the questionnaire ikThe linear function expression is:

[0096] R ik = k × R in +R i0 , where R in , R i0 Through linear fitting, each industry corresponds to a set of R in , R i0 .

[0097] The calculation formula of the power shortage cost R in the target area is:

[0098]

[0099] Where m = 8, β i is the weight coefficient of industry i, and its calculation formula is:

[0100]

[0101] Among them, GDP i is the annual GDP output value of all users in industry i in the target area, E i is the annual electricity consumption of all users in industry i in the target area, GDP T is the annual GDP output value in the target area, E T is the annual electricity consumption in the target area. For example, the target area for statistics can be Wuhan Zhuankou Demonstration Area, and the statistical year is 2018. At this time, GDP i is the GDP output value of all users in a certain industry in Wuhan Zhuankou Demonstration Zone in 2018, E i is the annual electricity consumption of the industry in 2018, E T is the total electricity consumption of Wuhan Zhuankou Demonstration Zone in 2018, GDP T It is the total GDP output value of Wuhan Zhuankou Demonstration Zone in 2018.

[0102] Using the above-mentioned line loss cost quantification method, the present invention selects Wuhan Zhuankou Demonstration Area as the target area. There are 135 10KV lines in the Wuhan Zhuankou Demonstration Area. The basic information of the 10KV lines in 2018 is collected from the power grid database platform; then, user dedicated lines, lines with large line loss deviations, and spare lines are excluded to obtain 49 sample lines. The percentage of the selected 49 sample lines to the total lines is 36.3%, which can completely cover the research scope of Wuhan Zhuankou Demonstration Area; finally, the unit load moment annual line loss electricity of the 49 sample lines is calculated, and each line corresponds to a unit load moment annual line loss electricity. After that, the average unit load moment annual line loss electricity of the 49 sample lines is calculated, and the obtained value is 27.2MWh / MVA·km. The purchasing price cost of Wuhan Power Supply Company is 0.389 yuan / KWh, so the cost of unit load moment annual line loss electricity is: In other words, the quantified result of line loss cost in Zhuankou Demonstration Area is 10,500 yuan / MVA·km.

[0103] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for calculating accurate investment in a distribution network planning project, characterized in that: The steps include: (1) Collect basic information of each line in the target area through the power grid database platform, exclude user-specific lines, lines with large line loss deviations, and spare lines, obtain sample lines, and calculate the cost of line loss electricity per unit load moment; (2) Obtaining power shortage sample information of users in the target area through questionnaires, classifying the power shortage sample information according to the industries to which the users belong, and calculating the power shortage cost of the target area; The cost of calculating the annual line loss electricity per unit load moment in step (1) includes the following steps: (a) Calculate the equivalent line loss power, annual utilization hours, and equivalent load moment of each line in the sample line; (b) calculating the unit load moment annual line loss electricity of each line in the sample line, and calculating the average unit load moment annual line loss electricity of the sample line based on the unit load moment annual line loss electricity of each line; (c) Calculate the cost of line loss per unit load moment based on the average line loss per unit load moment of the sample line and the purchase cost per kilowatt-hour; The equivalent line loss power P of the i-th line in the sample line Ei The calculation formula is: Where, ΔE ij is the daily line loss of the i-th line on the j-th day, E ij is the daily power supply of the i-th line on the j-th day, P ij is the rated capacity of one of the distribution transformers on the i-th line on the j-th day, and m is the number of lines in the sample line; The annual utilization hours H of the i-th line in the sample line Ui The calculation formula is: Where E is the annual cumulative power supply of the ith line, P ik is the rated capacity of the kth distribution transformer on the i-th line, and n is the number of distribution transformers installed on the i-th line; The equivalent load moment P of the i-th line in the sample line Li The calculation formula is: Among them, Z i is the impedance of the ith line, Z iN is the reference impedance, L i is the length of the ith line, K is the weight coefficient, and its expression is as follows: Unit load moment annual line loss ΔE of the i-th line in the sample line Li The calculation formula is: The average unit load moment annual line loss of m lines in the sample line is ΔE L The calculation formula is: The cost of annual line loss electricity per unit load moment C U The calculation formula is: C U =C×ΔE L Among them, C is the purchase cost per kilowatt-hour: Calculating the power shortage cost of the target area in step (2) includes the following steps: (d) Calculate the reliability power loss cost and power shortage cost for each user in each industry at different power outage durations; (e) The weighted average method is used to calculate the power outage cost of each industry under different power outage durations, and a discrete sample of the power outage cost of each industry is obtained; (f) Linear regression method is used to transform the discrete samples of power outage costs of various industries into linear functions with power outage time as the independent variable; (g) Using weight coefficients to adjust the power shortage costs of various industries, thereby calculating the power shortage costs of the target area; The reliability power loss cost P corresponding to the power outage duration k hours for user j in industry i ijk The calculation formula is: Among them, i=1 represents a bank data center, i=2 represents a commercial center, i=3 represents an industrial and commercial outlet, i=4 represents a restaurant, i=5 represents a mechanical processing center, and i=6 represents a resident; C ijk E is the estimated cost loss of user j in industry i when the power outage lasts k hours; ij is the annual electricity consumption of user j in industry i during a statistical period of one year; H ij h is the annual electricity consumption hours of user j in industry i during a statistical period of one year; The power shortage cost RC corresponding to the power outage duration k hours for user j in industry i ijk The calculation formula is: Among them, k is the duration of power outage; The power shortage cost R corresponding to the power outage duration k hours in industry i ik The calculation formula is: Where n is the number of users of the questionnaire in industry i; The power shortage cost R corresponding to the power outage duration k hours in industry i ik The linear function expression is: R ik =k×R in +R i0 ; The calculation formula of the power shortage cost R in the target area is: Among them, β i is the weight coefficient of industry i, and its calculation formula is: Among them, GDP i is the annual GDP output value of industry i in the target area, E i is the annual electricity consumption of industry i in the target area, GDP T is the annual GDP output value in the target area, E T is the annual electricity consumption in the target area.

2. The accurate investment calculation method for distribution network planning project according to claim 1 is characterized in that: The power grid database platform includes PMS2.0 system, EMS system, DMS system, PIS2.0 system, and synchronous line loss system; the basic information includes line name, line nature, line length, line impedance, proportion of public and private transformers, number of distribution transformers and corresponding rated capacity of distribution transformers, daily power supply, daily line loss, monthly power supply, monthly line loss, and annual cumulative power supply.

3. The accurate investment calculation method for distribution network planning project according to claim 1 is characterized in that: The user's power outage sample information includes the user's annual electricity consumption, the user's annual electricity consumption hours, and the user's cost loss estimates corresponding to different power outage durations.

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