CN104143159B - A kind of power distribution network health degree self-diagnosing method for considering regional disparity - Google Patents

Abstract

The invention relates to a method for self-diagnosing the health of distribution network considering regional differentiation, acquiring objects that affect the operation status of distribution network as first-level objects, obtaining second-level objects and third-level indicators, and establishing tree-shaped distribution network operation status system; according to the analytic hierarchy process, determine the weight value of objects and indicators at all levels; determine the scoring function type of each third-level indicator, and give the scoring formula of each third-level indicator based on the evaluation benchmark value and maximum/minimum value; The scoring formula is to obtain the comprehensive score of the distribution network for all levels of objects and index weight values; to find weak links in the distribution network according to the comprehensive score of the distribution network, and to take corresponding improvement measures; The regional differences are fully considered in the link process, and the real weak links of the distribution network are found in combination with the regional characteristics, which provides technical support for the safe operation of the distribution network.

Description

A distribution network health self-diagnosis method considering regional differences

technical field

The invention relates to a method for self-diagnosing the health degree of distribution network considering regional differentiation.

Background technique

As an important social infrastructure, the power grid plays an important role in optimizing resource allocation, ensuring energy security, and meeting the needs of economic and social development. It must have a reasonable structure, flexible operation, and be able to provide safe, reliable, high-quality, and efficient power supply. At the same time, in order to achieve scientific development of the power grid, the power grid enterprises, as the main body of grid investment and construction, must maintain certain profitability and sustainable development capabilities.

The distribution network is the link that directly faces the users in the power system, and has the most direct impact on the quality and reliability of the power supply of the users. The power supply capacity and power supply reliability of the entire power system to users are reflected through the distribution network. As far as the distribution network health of power supply enterprises is concerned, it is not only the result of the interaction of electrical parameters such as the voltage of each node in the network, the active (reactive power) loss of the branch, and the grid structure, but also the result of the operation, production, planning management, engineering construction, etc. A comprehensive reflection of the work efficiency and work level of the business and production departments. Therefore, carrying out a comprehensive evaluation of the operation status of the distribution network and identifying the weak links in it are very important for improving the reliability of the distribution network, ensuring the quality of power energy, promoting and improving the production technology and management level of the power industry, and improving economic and social benefits. Significance.

my country is a vast country, and there are great differences in economic development and natural environment among regions. Since the reform and opening up, especially since the 1990s, my country's economy has developed rapidly and its economic strength has been significantly enhanced. However, there are also obvious economic differences between the eastern coastal areas and the backward areas in the central and western regions. The rapid development is in stark contrast. The unbalanced development of the region makes this gap gradually widen. There are imbalances in the industrial structure and per capita GDP in the eastern, central and western regions. my country is a country with a vast territory. There are big differences in terms of development and natural environment. Since the reform and opening up, especially since the 1990s, my country's economy has developed rapidly and its economic strength has been significantly enhanced. However, there are also obvious economic differences between the eastern coastal areas and the backward areas in the central and western regions. The rapid development is in stark contrast, and the unbalanced development of the region makes this gap gradually widen. There are imbalances in the industrial structure and per capita GDP of the eastern, central and western regions. Due to differences in economic level and power consumption level in different regions, regional differences should be considered when evaluating the distribution network.

Contents of the invention

The purpose of the present invention is to provide a self-diagnosis method for the weak links of the distribution network considering regional differences, to provide a basis for the planning and transformation of the power network, to improve the reliability of the distribution network, ensure the quality of electric energy, and promote and improve the production technology of the electric power industry.

In order to achieve the above purpose, the steps of a self-diagnosis method for distribution network health degree considering regional differentiation of the present invention are as follows:

(1) Obtain the objects that affect the operation of the distribution network as the first-level objects, including grid structure, power supply quality, power grid security, equipment level, power supply efficiency and benefit, power grid development coordination and operation and maintenance level;

(2) Obtain the second-level objects belonging to each first-level object and the third-level indicators belonging to each second-level object according to the first-level objects obtained in step (1), and establish a tree-like distribution network operating status system;

(3) According to the analytic hierarchy process, determine the weight values of objects and indicators at all levels;

(4) Divide the areas with the same status in a large area into N types of areas according to the administrative level and power load density, and then according to the distribution of the third-level indicators in various areas, the average value of the indicators of the same area in all areas is obtained as The benchmark value of the indicator, the benchmark value, the maximum/minimum value of the indicator in the same region and the area of each type of area are combined to obtain the evaluation benchmark value and the maximum/minimum value of the evaluation; determine the scoring function type of each third-level index, and based on the evaluation The benchmark value and the maximum/minimum value give the scoring formula of each three-level indicator;

(5) Obtain the comprehensive score of the distribution network according to the scoring formula of each index, that is, the objects at all levels and the index weight value;

(6) Find the weak links in the distribution network according to the comprehensive score of the distribution network, and take corresponding improvement measures.

Further, the sum of the weight values of all first-level objects in the step (3) is equal to 1, the sum of the weight values of all second-level objects subordinate to each first-level object is equal to 1, and the sum of all third-level indicators subordinate to each second-level object The sum of the weight values equals 1.

Further, the order of the step (3) and the step (4) can be interadjusted.

Further, in the step (4), the area is divided into six types of areas A+, A, B, C, D, and E, and the calculation formulas of the evaluation reference value R _ef and the maximum value R _m are as follows:

Among them, S _A+ is the area of an A+ area in a certain region, R _A+ is the benchmark value of an indicator in an A+ area, R _A+m is the maximum value of an indicator in an A+ area, and so on.

Further, the scoring function types of the three-level indicators in the step (4) are divided into increasing type, decreasing type and moderate type.

Further, when the scoring function is incremental, the scoring formula is as follows:

in, It is the scoring value when the statistical value of the indicator in this area is R _ef .

Further, when the scoring function is decreasing, the scoring formula is as follows:

Further, when the scoring function is moderate, the scoring formula is as follows:

Further, the formula for calculating the comprehensive score of the distribution network in step (5) is:

In the formula, n is the number of first-level objects, k _1i represents the weight of first-level objects; m _i represents the number of second-level objects under the i-th first-level object, k _2ij represents the weight of the corresponding second-level object; l _j represents the weight of the first-level object The number of third-level indicators under j second-level objects, p _k represents the weight of the corresponding third-level indicators; score _k represents the score of the kth third-level indicators.

In the step (6), the weak link in the distribution network is found by using the two-dimensional tracking method, using the weighted score rate of the object and index as the scale, and comparing the score rate of the first-level object horizontally to find out the relatively weak link. Then, starting from the relatively weak major links, through vertical layer-by-layer tracking, find out the weak points in the second-level and third-level indicators in turn, and then use the raw data analysis on site to analyze from the distribution network technical equipment and The cause of the weak point is excavated during the whole production process.

The self-diagnosis method of the weak links of the distribution network considering regional differences in the present invention fully considers the regional differences in the process of finding the weak links of the distribution network, and finds the real weak links of the distribution network in combination with the characteristics of the region, so as to provide a better solution for the power distribution network. Provided technical support for the safe operation of the network.

Description of drawings

Fig. 1 is the flowchart of the embodiment of the present invention;

Figure 2 is a diagram of the index scoring function type;

Figure 3 is a structural diagram of the distribution network health diagnosis system.

Detailed ways

As shown in Figure 1, the steps of a self-diagnosis method for distribution network health considering regional differences are as follows:

(1) Obtain the objects that affect the operation of the distribution network as the first-level objects, including grid structure, power supply quality, power grid security, equipment level, power supply efficiency and benefit, power grid development coordination and operation and maintenance level;

(2) Obtain the second-level objects belonging to each first-level object and the third-level indicators belonging to each second-level object according to the first-level objects obtained in step (1), and establish a tree-like distribution network operating status system;

(3) According to the analytic hierarchy process, determine the weight values of objects and indicators at all levels;

(4) Divide the areas with the same status in a large area into N types of areas according to the administrative level and power load density, and then calculate the average value of the indicators of the same area in all areas according to the distribution of the third-level indicators in various areas As the benchmark value of the indicator, the benchmark value, the maximum/minimum value of the indicator in the same region are combined with the area of each type of area to obtain the evaluation benchmark value and the maximum/minimum value of the evaluation; determine the scoring function type of each third-level index, and based on The evaluation benchmark value and the maximum/minimum value give the scoring formula of each three-level index;

(5) Obtain the comprehensive score of the distribution network according to the scoring formula of each index, that is, the objects at all levels and the index weight value;

(6) Find the weak links in the distribution network according to the comprehensive score of the distribution network, and take corresponding improvement measures.

The establishment of the distribution network operation status system must fully consider the characteristics of the distribution network to ensure the practicability and operability of the index system, that is, in the selection of evaluation indicators, it should be accurate, standardized and comparable; in terms of the source of evaluation index data, It should be true and reliable; in terms of evaluation results, it should be objective and comprehensive. According to the purpose of statistical evaluation, select appropriate statistical indicators and establish a diagnostic index system that can reflect the main problems of the evaluation object from different angles and aspects.

Adopt the evaluation index system design criteria commonly used by the World Bank and national government departments - SMART criteria, to build a specific, measurable, available, relevant, and trackable distribution network operating status system. Horizontally, the system covers seven links: grid rationality, power supply quality, grid security, equipment level, power supply quality and efficiency, grid development coordination, and operation and maintenance level. Vertically, it is subdivided into three-level indicators, referred to as seven A three-level index system.

AHP is an effective method for quantitative analysis of non-quantitative events and objective analysis of subjective judgments in the decision-making process. Analytic Hierarchy Process divides a complex problem into several orderly levels by dividing the relationship between various indicators. The status of each element in each layer is equal, and there is a certain subordinate relationship between the upper layer and the lower layer, which has an orderly hierarchical level.

The basic levels generally included in the hierarchical structure model are: target level, criterion level and scheme level, etc. In the hierarchical hierarchical model, according to the judgment of certain objective facts, the importance of each layer is quantified, that is, by establishing a judgment matrix to compare and judge the relative importance of two elements. Then use relevant mathematical methods to calculate the relative importance weight of each index in each level. Finally, through the combination of the relative importance weights of each level in the hierarchical structure, the weights of the importance of all indicators relative to the decision-making objectives are obtained.

In decision-making with limited objectives, the decision-making problem needs to combine qualitative factor analysis and quantitative factor analysis to avoid disconnection between the two. The AHP can well realize the combination of qualitative analysis and quantitative analysis, so as to realize scientific decision-making.

In actual engineering, there are three types of index scoring functions: decreasing type, increasing type and moderate type. Due to the differences in economic development and electricity consumption levels in various regions, the differences in various regions should be considered when scoring each indicator. Assuming the evaluation reference value R _ef and the highest value R _m (or R _n ) of a certain indicator in the diagnosed area, the calculation method is as follows:

Among them, S _A+ is the area of an A+ area in a certain region, R _A+ is the benchmark value of an indicator in an A+ area, R _A+m is the maximum value (or minimum value) of an indicator in an A+ area, and so on.

When the scoring function is incremental (see Figure 2), the scoring formula is as follows:

in, It is the scoring value when the statistical value of the indicator in this area is R _ef .

When the scoring function is decreasing (see Figure 2), the scoring formula is as follows:

When the scoring function is moderate (see Figure 2), the scoring formula is as follows:

The formula for calculating the comprehensive score of the distribution network is:

In the formula, n is the number of first-level objects, k _1i represents the weight of first-level objects; m _i represents the number of second-level objects under the i-th first-level object, k _2ij represents the weight of the corresponding second-level object; l _j represents the weight of the first-level object The number of third-level indicators under j second-level objects, p _k represents the weight of the corresponding third-level indicators; score _k represents the score of the kth third-level indicators.

Based on the above content, the distribution network in Henan Province is taken as an example to illustrate this self-diagnosis method for distribution network health considering regional differences. Taking China as a large region, and some provincial power supply areas within China as regions, each region is divided into six types of regions: A+, A, B, C, D, and E according to administrative level and power load density. The power supply area of Henan Provincial Electric Power Company is 12198km ² in municipal districts and 123130km ² in counties, totaling 135328km ² . There are no A+ and E areas, the A-type power supply area is 258km ² , the B-type power supply area is 1349km ² , the C-type power supply area is 6489km ² , and the D-type power supply area is 127255km ² .

(1) Index statistics

Based on relevant technical data such as power grid development diagnosis and analysis report, power grid rolling planning report, and distribution network professional summary report, the present value of various indicators of Henan Electric Power Company in 2012 is obtained through statistics, as shown below.

Table 1 Index level of Henan Electric Power Company in 2012

(2) Index scoring formula

The following three indicators, the reliability rate of power supply (RS-3), the proportion of heavy-duty distribution transformers and the average load rate of distribution transformers, are used to illustrate the index scoring method when regional differences are considered.

1) Power supply reliability rate (RS-3)

The index setting is based on the "Regulations for Evaluation of Power Supply Reliability of Power Supply System Users" (DL/T836-2003), which is used to quantitatively measure the degree of reliable power supply from the power supply network to users. The scoring function of this index is incremental. According to the 2013 State Grid distribution network statistics of provincial companies, the lowest value of power supply reliability (RS-3) is 98.93% of Tibet Autonomous Region, the highest value is 99.993% of Beijing, and the average value of State Grid is 99.797%. Among them, the average value of class A+ areas is 99.993%, the average value of class A areas is 99.961%, the average value of class B areas is 99.904%, the average value of class C areas is 99.810%, the average value of class D areas is 99.481%, and the average value of class E areas The value is 97.422%. Taking Henan Province as an example, the reliability rate of power supply in Class A areas is 99.981%, that of Class B areas is 99.952%, that of Class C areas is 99.902%, and that of Class D areas is 99.858%, totaling 99.888%.

Table 2 Distribution table of power supply reliability (RS-3) of State Grid companies

Based on the above data, the average value of indicators in various regions of the country is taken as the benchmark value R _i of indicators in this type of region, that is, R _{A +} =99.993%, RA =99.962%, R _B =99.904%, R _C =99.810%, R _D = 99.481%, RE ₌ 97.422%; take the maximum value of indicators in various regions of the country as the highest scoring value of this type of region, that is, R _A+m =99.997%, R _Am =99.998%, R _Bm =99.981%, R _Cm = 99.968%, R _Dm =99.961%, R _Em =99.842%. Since there are no A+ and E areas in the power supply area of Henan Province, they are not considered. The evaluation reference value R _ef and the highest evaluation value R _m of the power grid evaluation index power supply reliability rate (RS-3) are:

Assume that when the statistical value reaches R _ef , the score is 60 points; when the statistical value reaches R _m , the score is 100 points. To sum up, the scoring formula for the power supply reliability rate (RS-3) of the power grid evaluation index in Henan Province is:

According to the statistics, the total value of the power supply reliability rate (RS-3) in Henan Province is 99.888%. According to the above scoring formula, the score of this indicator for the distribution network in Henan Province is 91.82 points.

2) Proportion of heavy-duty distribution transformer

This index is applicable to 10kV medium voltage distribution network, and is used to describe the proportion of heavy load of medium voltage distribution transformer. The scoring function of this index is decreasing type. According to the 2013 State Grid provincial distribution network statistics, the lowest proportion of heavy-duty distribution transformers is 0.9581% in Qinghai Province, the highest value is 14.5622% in Hubei Province, and the average is 7.211%. Among them, the average value of class A+ areas is 6.0089%, the average value of class A areas is 3.9874%, the average value of class B areas is 6.5795%, the average value of class C areas is 8.3278%, the average value of class D areas is 7.9332%, and the average value of class E areas The value is 5.2752%. Taking Henan Province as an example, there are no A+ and E areas. The proportion of heavy-duty distribution transformers in A areas is 6.9192%, that of B areas is 8.8133%, that of C areas is 13.5712%, and that of D areas is 14.7645%. It is 13.8184%.

Table 3 distribution table of distribution transformer overload rate of various companies of State Grid

Based on the above data, the average value of indicators in various regions of the country is taken as the reference value R _i of indicators in this type of region, that is, R _{A +} =6.0089%, RA =3.9874%, R _B =6.5795%, R _C =8.3278%, R _D = 7.9332%, R _E =5.2752%; the minimum value of the indicators of various regions in the country is the highest score value of this type of region, that is, R _A+n =2.5272%, R _An =0%, R _Bn =0%, R _Cn = 2.7528%, R _Dn =0.8694%, R _En =0.0768%. Since there are no A+ and E-type areas in the power supply area of Henan Province, they are not considered. The evaluation reference value R _ef and the highest score value R _n of the heavy-duty distribution transformer ratio of the power grid evaluation index are:

Assume that when the statistical value is less than R _n , the score is 100; when the statistical value reaches Ref, the score is 60; when the statistical value is higher than R _m = _14.5622 %, the score is 0. To sum up, the scoring formula for the proportion of heavy-duty distribution transformers in Henan Province’s power grid evaluation index is:

According to statistics, the total value of the proportion of heavy-duty distribution transformers in Henan Province is 13.8184%. According to the above scoring formula, the score of this indicator in Henan Province's distribution network is 6.73 points.

3) Average load rate of distribution transformer

This indicator is applicable to 10kV medium voltage distribution network, and is used to describe the annual load rate of medium voltage distribution transformers. The scoring function of this indicator is moderate. According to the distribution network statistics of the provinces of the State Grid in 2013, the lowest average distribution transformer load rate is 20.44% of Tibet Autonomous Region, the highest value is 58.32% of Henan Province, and the average value is 40.68%. Among them, the average value of class A+ areas is 40.94%, the average value of class A areas is 43.15%, the average value of class B areas is 42.22%, the average value of class C areas is 42.92%, the average value of class D areas is 38.73%, and the average value of class E areas The value is 32.74%. Taking Henan Province as an example, there are no A+ and E areas. The average distribution transformer load rate in the A area is 68.91%, that in the B area is 60.22%, that in the C area is 56.18%, and that in the D area is 53.58%. It is 58.32%.

Table 4 The average distribution table of the distribution transformer load rate of each company of the State Grid

Based on the above data, the average value of indicators in various regions of the country is taken as the benchmark value R _i of the indicators in this type of region, that is, R _A+ =40.94%, R _A =43.15%, R _B =42.22%, R _C =42.92%, R _D = 38.73%, RE ₌ 32.74%. Since there are no A+ and E-type areas in the power supply area of Henan Province, it is not considered. The evaluation reference value R _ef of the average distribution transformer load rate of the power grid evaluation index is:

Assume that when the statistical value is 40%-60%, the score is 100; when the statistical value reaches 80%, the score is 0. To sum up, the scoring formula for the average load rate of the power grid evaluation index distribution transformer in Henan Province is:

According to statistics, the total value of the average load rate of distribution transformers in Henan Province is 58.32%. According to the above scoring formula, the score of this indicator for Henan Province's distribution network is 100 points.

4) Scoring formula for each index

According to the above process and principles, the evaluation methods of each index can be formulated, and an index scoring formula can be obtained, as shown in the following table.

Table 5 Scoring formulas for each indicator

(3) Index weights at all levels

The system determines the weight of each index according to the AHP, as shown in the table below.

Table 6 Index weights at all levels

(4) Comprehensive score

The single index score reflects the specific situation of the power grid from different aspects, and then uses the analytic hierarchy process to calculate layer by layer to obtain the comprehensive diagnostic score of the entire distribution network.

According to the above distribution network diagnosis comprehensive scoring formula, the comprehensive score of distribution network health diagnosis of Henan Electric Power Company is 59.21 points. Combining the index scores of each layer, according to the two-dimensional tracking method, we can find the weak points in the enterprise power grid itself and business flow. The specific method is: use the index weighted score rate as a scale, first compare the score rate of the first-level indicators horizontally, and find out the relatively weak links; then, start from these links, and track them vertically to find out The weak points in the second-level and third-level indicators, with the help of on-site raw data analysis, can actually dig out the causes of weak points from the distribution network technology equipment and the whole production process, and propose corresponding improvement measures.

From the perspective of the first-level object, the biggest link that restricts the improvement of the health level of the distribution network of the company in Henan Province is the security of the power grid, and its score is only 38.58 points. Tracking down, all of its secondary objects scored very low, especially the 10kV part, which scored only 10.28 points. Continuing to track down, the heavy load of 10kV distribution transformers is quite serious, much higher than the average level of the State Grid companies. The reason is that, on the one hand, the investment capacity of the medium-voltage distribution network is limited, which causes the growth rate of the distribution transformer capacity to lag behind the load growth rate, and the overall load rate of the distribution transformer is relatively high; The problem is prominent. Corresponding improvement measures, one is to increase the distribution transformer capacity based on the principle of "small capacity, more distribution points"; the second is to balance the distribution transformer load through load optimization and power cut; the third is to carry out demand side management, through orderly use Electricity, reduce distribution transformer load rate.

Claims (4)

1. A distribution network health degree self-diagnosis method considering region differentiation is characterized by comprising the following steps:

(1) Acquiring objects influencing the operation condition of the power distribution network as primary objects, wherein the primary objects comprise a grid structure, power supply quality, power grid safety, equipment level, power supply efficiency and benefit, power grid development coordination and operation maintenance level;

(2) Acquiring secondary objects subordinate to the primary objects and tertiary indexes subordinate to the secondary objects according to the primary objects obtained in the step (1), and establishing a tree-shaped power distribution network operation condition system;

(3) Determining each level of object and index weight value according to an analytic hierarchy process;

(4) Dividing areas which are located at the same position in a large area into N types of areas according to administrative levels and power load density, obtaining the average value of the same type of area indexes of all the areas as the reference value of the indexes according to the distribution of the three types of indexes in all the areas, and combining the reference value and the maximum/small value of the indexes in the same type of areas with the areas of all the areas to obtain an evaluation reference value and an evaluation maximum/small value; determining the scoring function type of each three-level index, and giving a scoring formula of each three-level index according to the evaluation reference value and the maximum/small value;

(5) Obtaining the comprehensive score of the power distribution network according to the scoring formula of each index, each level of object and the index weight value;

(6) Weak links in the power distribution network are searched according to the comprehensive scores of the power distribution network, and corresponding improvement measures are taken;

in the step (4), the area is divided into six areas of A +, A, B, C, D and E, and then the reference value R is evaluated _ef And maximum value R _m The calculation formula of (c) is as follows:

wherein S _A+ Is the area of a certain region of class A +, R _A+ Is a reference value of some index in A + type area, R _A+m The maximum value of a certain index in the A + type area is obtained by analogy;

the scoring function types of the three-level indexes in the step (4) are an increasing type, a decreasing type and a moderate type;

when the scoring function is incremental, the scoring formula is as follows:

wherein,the statistical value of the index for the region is R _ef A time scale value;

when the scoring function is decreasing, the scoring formula is as follows:

when the scoring function is moderate, the scoring formula is as follows:

the comprehensive score calculation formula of the power distribution network in the step (5) is as follows:

wherein n is the number of primary objects, k _1i Representing a primary object weight; m is a unit of _i Number of secondary objects under ith primary object, k _2ij Representing a weight of the corresponding secondary object; l. the _j Represents the number of three-level indexes under the jth secondary object, p _k Representing the weight of the corresponding three-level index; score _k Representing the kth tertiary index score;

wherein R is _n R1, R2, R3, R4 are set statistical values participating in scoring, and R1 is the minimum index value<R2<R3<R4。

2. The self-diagnosis method for health degree of distribution network according to claim 1, considering regional differentiation, wherein the method comprises the following steps: in the step (3), the sum of the weight values of all the primary objects is equal to 1, the sum of the weight values of all the secondary objects subordinate to each primary object is equal to 1, and the sum of the weight values of all the tertiary indexes subordinate to each secondary object is equal to 1.

3. The self-diagnosis method for health degree of distribution network according to claim 1, considering regional differentiation, wherein the method comprises the following steps: the sequence of the step (3) and the step (4) can be intermodulation.

4. The self-diagnosis method for health degree of distribution network according to claim 1, considering regional differentiation, wherein the method comprises the following steps: the weak link in the power distribution network is searched in the step (6), a two-dimensional tracking method is adopted, the object and index weighted score ratios are used as scales, the first-level object score ratios are transversely compared, and a relatively weak big link is found out; then starting from the relatively weak large link, sequentially finding out weak points in the second-level index and the third-level index through longitudinal layer-by-layer tracking, and excavating reasons for the weak points in the whole distribution network technical equipment and production process by means of field original data analysis.