Method for on-line identification of metering anomalies of special transformer districts and public transformer districts of medium-voltage branch lines

Abstract

The invention discloses a method for on-line identification of metering anomalies of a special transformer district and a public transformer district of a medium-voltage branch line, and the method comprises the following steps: (1) collecting the data of the primary side current of an outgoing line of the medium-voltage branch line through power distribution automation equipment; meanwhile, according to the secondary side current data, collected by the main metering collection device, of all the special transformer and public transformer metering devices under the branch lines, the real-time data change trend is determined by combining the transformation ratio data of the current transformers of the special transformer and public transformer districts; (2) judging whether the secondary current is abnormal or not according to the real-time data change, and (3) in the same period, if delta is greater than 10%, indicating that the secondary side current of the special transformer or the public transformer under the branch line is abnormal, and automatically assigning the abnormal medium-voltage branch line to related workers by the system. According to the invention, the online identification of the metering abnormity of the special transformer and public transformer districts on the medium-voltage branch lines is realized for the first time, and the problem that the abnormal special transformers and public transformers cannot be identified in time due to the large number of medium-voltage branch lines and the large number of special transformers and public transformers for a long time is solved.

Description

TECHNICAL FIELD

[0001] The application relates to a power line loss treatment technology, in particular to a method for online identification of metering abnormities of special transformers and public transformers in a medium-voltage branch line. BACKGROUND

[0002] In order to guarantee the economic benefits of power grid enterprises and prevent the loss of state-owned assets, line loss treatment becomes the most important thing for the power grid enterprises. The special transformer and public transformer area are particularly important in the medium-voltage line loss treatment because of large electricity. However, the branch line is more in the medium-voltage line loss treatment, and the number of special transformers and public transformers is large, so that the current treatment of the metering abnormities of the special transformers and public transformers is passive. The monitoring is not in place, the discovery is not timely, and the judgment is not accurate, so that an online automatic identification method for the metering abnormities of the special transformers and public transformers is urgently needed to timely discover the metering abnormities of the special transformers and public transformers and timely handle the metering abnormities to maintain the normal power supply and use order. SUMMARY

[0003] The application solves the technical problem of overcoming the defects of the prior art and providing an online identification method for the metering abnormities of special transformers and public transformers in a medium-voltage branch line, which is reasonable in design, timely in handling abnormities, and capable of maintaining the normal power supply and use order.

[0004] The technical scheme of the application is as follows.

[0005] An online identification method for the metering abnormities of special transformers and public transformers in a medium-voltage branch line comprises the following steps.

[0006] (1) Real-time data of the current on the primary side of the outgoing line of the medium-voltage branch line is collected through the power distribution automation equipment, and the secondary side current data of all the special transformers and public transformers in the branch line are collected through the main metering collection device. The current transformer ratio data of the special transformer and public transformer area are combined, and if the special transformer and public transformer are measured on the low-voltage side, the transformer ratio of the special transformer and public transformer is also considered to determine the real-time data change trend.

[0007] (2) Whether the secondary current is abnormal is judged according to the real-time data change. The primary side current collected by the outgoing line of the branch line is represented by i, the primary side current obtained by calculating the secondary side current of the special transformer and public transformer of the branch line is represented by i', and the secondary side current of each special transformer and public transformer is represented by l1, l2...l n , the ratio data of the current transformer is represented by k1, k2...k n , and the transformer ratio of the special transformer and public transformer is represented by η. The transformer ratio of the special transformer and public transformer measured on the high-voltage side can be set as a fixed value 1, and the transformer ratio of the special transformer and public transformer measured on the low-voltage side is calculated according to the actual value, so that i' = l1k1 / η1 + l2k2 / η2 +...+ l n k n / η n , error coefficient is made:

[0008] Delta = (i-i') / i x 100%

[0009] (3). According to the real-time whole point data every day, three whole point data are a period, in the same period, if all the delta is greater than 10%, it indicates that the secondary side current of the special transformer or the public transformer in the branch line exists abnormity, that is, the metering of the special transformer or the public transformer is abnormal, and the abnormal medium voltage branch line is automatically assigned to the related staff, and on-site investigation and treatment are carried out;

[0010] (4). The next set of real-time data is taken for analysis and calculation, and a working cycle is completed.

[0011] The beneficial effects of the application are:

[0012] 1. The application realizes online identification of metering abnormity of the special transformer and the public transformer in the medium voltage branch line for the first time, solves the problem that the number of the medium voltage branch line, the special transformer and the public transformer is large, and the abnormal special transformer and the public transformer cannot be identified in time.

[0013] 2. The application takes the primary current of the medium voltage branch line and the secondary current of the metering device of the special transformer and the public transformer under the branch line as the criterion for judging the metering abnormity of the special transformer and the public transformer under the medium voltage branch line, and combines the current transformer ratio of the metering device of the special transformer and the public transformer and the ratio data of the special transformer and the public transformer measured at the low voltage side, so that the identification accuracy of the metering abnormity of the special transformer and the public transformer in the medium voltage branch line is extremely high.

[0014] 3. The application has reasonable design, can timely find the behavior of the metering abnormity of the special transformer and the public transformer, timely handle, maintain the normal power supply order, and has good economic benefits after popularization. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is a flow chart of the method for online identification of metering abnormity of the special transformer and the public transformer in the medium voltage branch line;

[0016] Figure 2 It is an actual application diagram of the application;

[0017] Figure 3 It is a primary side A, C phase current data diagram;

[0018] Figure 4 It is a secondary side A, C phase current data diagram measured at the high voltage side;

[0019] Figure 5 It is a current transformer ratio data diagram;

[0020] Figure 6 It is a schematic diagram of the medium voltage branch line;

[0021] Figure 7 Schematic diagram of short-circuiting current transformer leading to undercounting of current. DETAILED DESCRIPTION:

[0022] Embodiment: Referring to Figures 1-7 , the figure:

[0023] Method for online identification of metering abnormality of special transformer and public transformer in medium-voltage branch line:

[0024] The steps are as follows:

[0025] (1) Real-time data of current at the primary side of the outgoing line of the medium-voltage branch line is collected through the power distribution automation equipment, and at the same time, secondary-side current data of all special transformers and public transformers in the branch line are collected through the main metering collection device, and the current transformer ratio data of the special transformer and public transformer area (if the special transformer and public transformer are metered at the low-voltage side, the transformer ratio of the special transformer and public transformer also needs to be considered) are combined to determine the real-time data trend.

[0026] (2) Whether the secondary current is abnormal is determined according to the current values at the primary side of the medium-voltage branch line and at the secondary side of the special transformer and public transformer metering device and the ratio data of the current transformer (if the special transformer and public transformer are metered at the low-voltage side, the transformer ratio of the special transformer and public transformer also needs to be considered). The current at the primary side collected by the branch line is represented by i, and the current at the primary side obtained by calculating the secondary-side current of the special transformer and public transformer of the branch line is represented by i'. The secondary-side current of each special transformer and public transformer is represented by l1, l2...l n , the ratio data of the current transformer is represented by k1, k2...k n , and the transformer ratio of the special transformer and public transformer is represented by η. The transformer ratio of the special transformer and public transformer metered at the high-voltage side can be set as a fixed value of 1, and the transformer ratio of the special transformer and public transformer metered at the low-voltage side is calculated according to the actual value. Then i' = l1k1 / η1 + l2k2 / η2 +... + l n k n / η n , and an error coefficient is formulated:

[0027] Δ = (i - i') / i × 100%

[0028] (3) Real-time data at the whole point is analyzed every day, and three whole point data in succession are a period. In the same period, if Δ is greater than 10% all the time, it indicates that there is an abnormality in the secondary-side current of the special transformer or public transformer under the branch line, i.e., metering abnormality of the special transformer or public transformer, and the system automatically assigns the abnormal medium-voltage branch line to the relevant staff for on-site investigation and treatment.

[0029] (4) The next set of real-time data is taken for analysis and calculation.

[0030] Actual application:

[0031] Practical applications of online metering anomaly identification for medium-voltage branch line dedicated transformers and public transformer substations, such as... Figure 2 As shown, real-time data of the primary current of the medium-voltage branch line is collected by distribution automation equipment. Simultaneously, secondary current data of all dedicated and public transformers under the branch line are collected by metering and acquisition devices. Combined with the current transformer ratio data of the dedicated and public transformer areas (if the dedicated and public transformers are metered on the low-voltage side, their transformer ratios must also be considered), it can be determined whether the secondary current of the medium-voltage branch line is normal. If abnormal data is found for three consecutive full-hour intervals, the abnormal dedicated and public transformer areas are automatically identified through analysis and calculation, and on-site inspection and handling are carried out.

[0032] Taking a medium-voltage branch line as an example, if this branch line only has one dedicated transformer for metering on the high-voltage side, then the transformer ratio is a fixed value of 1. The primary current collected by the distribution system, the secondary current collected by the power acquisition system for metering on the high-voltage side, and the current transformer ratio data are respectively as follows: Figures 3-5 As shown.

[0033] Through real-time data calculation and analysis, it was found that the Δ value for three consecutive full-hour data points within the same period did not meet the requirement of being greater than 10%. Therefore, the metering of the dedicated transformer and public transformer substations on this medium-voltage branch line is currently normal. Because this identification method is real-time and online, any metering anomalies in dedicated or public transformers will be detected and addressed promptly.

[0034] Case Study:

[0035] Taking a medium-voltage branch line as an example, the 10kV medium-voltage branch line has two dedicated transformers and one public transformer. The line is as follows: Figure 6 As shown.

[0036] Analysis was performed based on real-time data collected by the distribution automation system and the power acquisition system. The data from points 1, 2, and 3 were taken as one cycle, and the collected data are shown in Tables 1 and 2. It should be noted that there is no B-phase current measured on the high-voltage side of the dedicated transformer. Where iu represents the A-phase secondary current, iv represents the B-phase secondary current, iw represents the C-phase secondary current, and k represents the current transformer ratio.

[0037] Table 1 Real-time data collected by the power acquisition system

[0038]

[0039]

[0040] Table 2 Real-time data collected by the power distribution automation system

[0041]

[0042] Because the branch line voltage level is 10kV, the low voltage side voltage of the transformer is 0.4kV, the transformer ratio measured at the low voltage side is 25, and the transformer ratio measured at the high voltage side is a fixed value 1, the calculated primary side current is shown in Table 3 in combination with the data in Table 1.

[0043] Table 3 Calculated primary side current of the branch line

[0044]

[0045] According to formula (1), the collected primary side current of the branch line and the calculated primary side current, the primary side current error coefficient of the branch line at the three integral points of 1 point, 2 point and 3 point can be calculated, which is shown in Table 4.

[0046] Table 4 Primary side current error coefficient of the branch line

[0047]

[0048] As shown in Table 4, the primary side current error coefficient Δ in the same period (the three integral points of 1 point, 2 point and 3 point) is greater than 10%, which indicates that the metering of the transformer or the transformer of the branch line is abnormal. The information of the medium voltage branch line is automatically assigned to the relevant staff by the system. The staff determines that the transformer 2 exists electricity stealing behavior through on-site investigation, and the on-site electricity stealing situation is shown in Table 5. Figure 7 After on-site evidence collection and investigation, the electricity fee and the default use fee of the electricity stealing user are collected according to the laws and regulations, the normal power supply and use order is maintained, the loss of state-owned assets is prevented, and the medium voltage line loss management level is effectively improved.

[0049] The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Any simple modification according to the technical essence of the present application still belongs to the scope of the technical solution of the present application.

Claims

1. A method for online identification of metering abnormalities of medium-voltage branch line private and public transformer substation, characterized in that : comprising the following steps: (1). Through the power distribution automation equipment to collect the real-time data of the branch line of the outgoing line side current, and according to the main metering device to collect all the special variable and public variable metering device secondary side current data, combined with the current transformer ratio data of the special variable and public variable area, if it is in the low voltage side of the special variable and public variable, also consider the transformer ratio of the special variable and public variable, to determine the real-time data trend; (2). According to the real-time data changes to determine whether the secondary current is abnormal, branch line out line collected to the primary side current with i indicates, through the calculation of branch line of special variable and public variable secondary current to get the primary side current with i' indicates, each special variable and public variable secondary current with l1, l2... l n Indicates that the current transformer ratio data with k1, k2... k n Indicates that the special variable and public variable transformer ratio with η indicates, the special variable and public variable ratio measured at the high voltage side of the transformer can be set to a fixed value 1, the special variable and public variable ratio measured at the low voltage side is calculated according to the actual value, then i' = l1k1 / η1 + l2k2 / η2 +... + l n k n / η n , make error coefficient: Δ = (i-i') / i x 100% (3). According to the real-time whole point data for analysis every day, continuous 3 whole point data is a period, in the same period, if Δ is greater than 10%, it is indicated that the secondary side current of the special variable or public variable under the branch line is abnormal, that is, the special variable or public variable metering is abnormal, the system will automatically assign the abnormal medium voltage branch line to the relevant staff, and the site will be surveyed and treated; (4). Take the next set of real-time data for analysis and calculation, complete a working cycle.

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