A method for locating single-phase disconnection fault in distribution network

Abstract

The invention relates to the technical field of fault location of distribution network, and specifically to a method for locating single-phase disconnection fault of distribution network, including decomposing and locating area, obtaining the number of low-voltage monitoring points, obtaining the voltage value and monitoring amount of the low-voltage monitoring point, constructing a comparison amount, comparing the monitoring amount with the comparison amount, recording the number of monitoring points that meet the comparison standard, comparing the number of monitoring points that meet the standard after each section with the number of monitoring points after each section, determining the area where the fault occurs, etc. The present invention sets the comparison amount, directly compares the comparison amount with the monitoring amount, obtains the offset, judges the offset, obtains the situation of the monitoring point, and directly judges according to the voltage obtained by monitoring and the number of existing monitoring points, does not need to be connected to other electronic devices for additional measurement, has a fast positioning speed, and is more accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of distribution network fault location, and in particular to a distribution network single-phase disconnection fault location method. Background Art

[0002] Due to factors such as aging of joints and external force damage, line breakage faults occur frequently in 10kV distribution networks. Traditional methods such as manual line patrol and line selection are often used, which takes a long time to locate faults and has low power supply reliability. In recent years, some line breakage fault analysis methods have emerged and been applied. For example, faults are diagnosed based on the imbalance of the three-phase voltage of the distribution transformer, and faults are diagnosed based on the equivalent impedance and sequence components of the line. These methods generally have the disadvantages of difficult threshold setting, no distinction between the phases of the line breakage, and being greatly affected by the operation mode. Alternatively, the distribution automation terminal in the 10kV distribution network is used to locate grounding faults, but this method requires a high coverage rate of distribution network automation equipment. Summary of the invention

[0003] In order to overcome the technical problems in the prior art of poor fault location effect and high requirements on equipment, the present invention provides a method for locating a single-phase disconnection fault in a distribution network.

[0004] The technical solution adopted by the present invention to achieve the above-mentioned purpose is: a method for locating a single-phase disconnection fault in a distribution network, comprising the following steps:

[0005] S1: Decompose the distribution network into regions to obtain multiple positioning areas;

[0006] S2: Obtain the number of low voltage monitoring points behind each positioning area;

[0007] S3: measuring the voltage value of each low voltage monitoring point, and obtaining the monitoring value of each low voltage monitoring point through data processing;

[0008] S4: construct comparison volume;

[0009] S5: Compare the monitoring quantity of each low voltage monitoring point with the constructed comparison quantity, and record the number of monitoring points whose voltage values ​​meet the comparison standard behind each positioning area;

[0010] S6: Compare the number of monitoring points in the positioning area with the largest number of monitoring points whose voltage values ​​meet the comparison standard behind the positioning area with the number of low-voltage monitoring points behind each positioning area. The positioning area with the same number of monitoring points is the fault area.

[0011] Preferably, the data processing in step S3 includes normalization processing, and its expression is:

[0012] m = [ Ua ， Ub ， Uc ] / 220 ;

[0013] in, For monitoring quantity, is the voltage value of phase A at the low voltage monitoring point, is the voltage value of phase B at the low voltage monitoring point, The voltage value of phase C at the low voltage monitoring point;

[0014] Preferably, the comparison amount in step S4 is:

[0015] n 1 = [ 0 ， 3 2 , 3 2 ] ;

[0016] n 2 = [ 3 2 , 0 ， 3 2 ] ;

[0017] n 3 = [ 3 2 , 3 2 , 0 ] ;

[0018] n 4 = [ 1 2 , 1 ， 1 2 ] ;

[0019] n 5 = [ 1 2 , 1 2 , 1 ] ;

[0020] n 6 = [ 1 , 1 2 ， 1 2 ] ;

[0021] in, is the comparison value of phase A disconnection of distribution transformer under Yy0 connection mode, is the comparison value of phase B disconnection of distribution transformer under Yy0 connection mode, is the comparison value of phase C disconnection of distribution transformer under Yy0 connection mode, is the comparison value of phase A disconnection of distribution transformer under Dy11 connection mode, is the comparison value of phase B disconnection of distribution transformer under Dy11 connection mode, It is the comparison quantity of phase C disconnection of distribution transformer under Dy11 connection mode;

[0022] Preferably, the step S5 of comparing the monitoring value of each low voltage monitoring point with the constructed comparison value specifically comprises subtracting the monitoring value from the six comparison values ​​to obtain six offsets, which are expressed as follows:

[0023] ;

[0024] The expression of the comparison standard is:

[0025] ;

[0026] in, Indicates An offset.

[0027] Compared with the prior art, the beneficial effect of the present invention lies in that by setting a comparison amount, the comparison amount is directly compared with the monitoring amount to obtain an offset, the offset is judged, and the situation of the monitoring point is obtained. The judgment is made directly based on the monitored voltage and the number of existing monitoring points. There is no need to connect other external electronic equipment for additional measurement, the positioning speed is fast, and the positioning is more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a flow chart of the method of the present invention.

[0029] Figure 2 This is a distribution diagram of the positioning areas of each segment in Example 2 of the present invention.

[0030] Figure 3 is S of Example 2 of the present invention dg The location distribution diagram of each segment area when a segment failure occurs. DETAILED DESCRIPTION

[0031] The specific implementation method of the single-phase disconnection fault location method of the distribution network of the present invention is as follows: Example 1: Figure 1 As shown, the following steps are included:

[0032] S1: Decompose the distribution network into regions to obtain multiple positioning areas;

[0033] S2: Obtain the number of low voltage monitoring points behind each positioning area;

[0034] S3: measuring the voltage value of each low voltage monitoring point, and obtaining the monitoring value of each low voltage monitoring point through data processing;

[0035] Data processing includes normalization, which is expressed as:

[0036] m = [ Ua ， Ub ， Uc ] / 220 ;

[0037] in, For monitoring quantity, is the voltage value of phase A at the low voltage monitoring point, is the voltage value of phase B at the low voltage monitoring point, The voltage value of phase C at the low voltage monitoring point;

[0038] S4: construct comparison volume;

[0039] The comparison amount is:

[0040] n 1 = [ 0 ， 3 2 , 3 2 ] ;

[0041] n 2 = [ 3 2 , 0 ， 3 2 ] ;

[0042] n 3 = [ 3 2 , 3 2 , 0 ] ;

[0043] n 4 = [ 1 2 , 1 ， 1 2 ] ;

[0044] n 5 = [ 1 2 , 1 2 , 1 ] ;

[0045] n 6 = [ 1 , 1 2 ， 1 2 ] ;

[0046] in, is the comparison value of phase A disconnection of distribution transformer under Yy0 connection mode, is the comparison value of phase B disconnection of distribution transformer under Yy0 connection mode, is the comparison value of phase C disconnection of distribution transformer under Yy0 connection mode, is the comparison value of phase A disconnection of distribution transformer under Dy11 connection mode, is the comparison value of phase B disconnection of distribution transformer under Dy11 connection mode, It is the comparison quantity of phase C disconnection of distribution transformer under Dy11 connection mode;

[0047] S5: Compare the monitoring quantity of each low voltage monitoring point with the constructed comparison quantity, and record the number of monitoring points whose voltage values ​​meet the comparison standard behind each positioning area;

[0048] The monitoring quantity of each low voltage monitoring point is compared with the constructed comparison quantity. Specifically, the monitoring quantity is subtracted from the six comparison quantities to obtain six offsets, which are expressed as follows:

[0049] ;

[0050] The expression of the comparison standard is:

[0051] ;

[0052] in, Indicates offset;

[0053] S6: Compare the number of monitoring points in the positioning area with the largest number of monitoring points whose voltage values ​​meet the comparison standard behind the positioning area with the number of low-voltage monitoring points behind each positioning area. The positioning area with the same number of monitoring points is the fault area.

[0054] Embodiment 2 comprises the following steps:

[0055] S1: Decompose the distribution network into multiple locations, and obtain multiple locations. The situation of each location is as follows: Figure 2 As shown, S a , S b , S c , S d , S e , S f , S g , S h , S j , S i , S k , S L All are regional decomposition points;

[0056] S2: Get the number of low voltage monitoring points behind each positioning area, where S c , S e , S f , S j , S i , S k , S L is a low voltage monitoring point, then the number of low voltage monitoring points behind each positioning area is: S ab =7, S bc =1, S bd =6, S de =2, S ef =1, S dg =4, S gh =2, S hi =1, S hj =1, S gk =2, S kL =1, where S ab Represents the regional decomposition point S a and S b The positioning area between S bc Represents the regional decomposition point S b and S c The positioning area between S bd Represents the regional decomposition point S b and S d The positioning area between S de Represents the regional decomposition point S d and S e The positioning area between S ef Represents the regional decomposition point S e and S f The positioning area between S dg Represents the regional decomposition point S d and S g The positioning area between S gh Represents the regional decomposition point S g and Sh The positioning area between S hi Represents the regional decomposition point S h and S i The positioning area between S hj Represents the regional decomposition point S h and S j The positioning area between S gk Represents the regional decomposition point S g and S k The positioning area between S kL Represents the regional decomposition point S k and S L The positioning area between

[0057] S3: measuring the voltage value of each low voltage monitoring point, and obtaining the monitoring value of each low voltage monitoring point through data processing;

[0058] Data processing includes normalization, which is expressed as:

[0059] m = [ Ua ， Ub ， Uc ] / 220 ;

[0060] in, For monitoring quantity, is the voltage value of phase A at the low voltage monitoring point, is the voltage value of phase B at the low voltage monitoring point, The voltage value of phase C at the low voltage monitoring point;

[0061] S4: construct comparison volume;

[0062] The comparison amount is:

[0063] n 1 = [ 0 ， 3 2 , 3 2 ] ;

[0064] n 2 = [ 3 2 , 0 ， 3 2 ] ;

[0065] n 3 = [ 3 2 , 3 2 , 0 ] ;

[0066] n 4 = [ 1 2 , 1 ， 1 2 ] ;

[0067] n 5 = [ 1 2 , 1 2 , 1 ] ;

[0068] n 6 = [ 1 , 1 2 ， 1 2 ] ;

[0069] in, is the comparison value of phase A disconnection of distribution transformer under Yy0 connection mode, is the comparison value of phase B disconnection of distribution transformer under Yy0 connection mode, is the comparison value of phase C disconnection of distribution transformer under Yy0 connection mode, is the comparison value of phase A disconnection of distribution transformer under Dy11 connection mode, is the comparison value of phase B disconnection of distribution transformer under Dy11 connection mode, It is the comparison quantity of phase C disconnection of distribution transformer under Dy11 connection mode;

[0070] S5: Compare the monitoring quantity of each low voltage measurement point with the constructed comparison quantity, and record the number of monitoring points whose voltage values ​​meet the comparison standard behind each positioning area;

[0071] The monitoring quantity of each low voltage measurement point is compared with the constructed comparison quantity. Specifically, the monitoring quantity is subtracted from the six comparison quantities to obtain six offsets, which are expressed as follows:

[0072] ;

[0073] The expression of the comparison standard is:

[0074] ;

[0075] in, Indicates offset;

[0076] The number of monitoring points whose voltage values ​​meet the comparison standard in each positioning area is: S ab =4, S bc =0, S bd =4, S de =0, S ef =0, S dg =4, S gh =2, S hi =1, S hj =1, S gk =2, S kL =1;

[0077] S6: Compare the number of monitoring points in the positioning area with the largest number of monitoring points whose voltage values ​​meet the comparison criteria with the number of low-voltage monitoring points in each positioning area. ab , S bd , S dg The number of monitoring points that meet the comparison criteria is the largest, which is 4, and S dg The number of monitoring points that meet the comparison criteria in the segment is the same as the number of low-voltage monitoring points behind it, such as Figure 3 As shown, S dg The segment is the area where the failure occurred.

[0078] The present invention is described by way of embodiments, and those skilled in the art will appreciate that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application belong to the protection scope of the present invention.

Claims

1. A method for locating a single-phase disconnection fault in a distribution network, characterized in that: The following steps are involved: S1: Decompose the distribution network into regions to obtain multiple positioning areas; S2: Obtain the number of low voltage monitoring points behind each positioning area; S3: measuring the voltage value of each low voltage monitoring point, and obtaining the monitoring value of each low voltage monitoring point through data processing; S4: Construct a comparison amount; the comparison amount is: Among them, n1 is the comparison amount of the phase A line break of the distribution transformer under the Yy0 connection mode, n2 is the comparison amount of the phase B line break of the distribution transformer under the Yy0 connection mode, n3 is the comparison amount of the phase C line break of the distribution transformer under the Yy0 connection mode, n4 is the comparison amount of the phase A line break of the distribution transformer under the Dy11 connection mode, n5 is the comparison amount of the phase B line break of the distribution transformer under the Dy11 connection mode, and n6 is the comparison amount of the phase C line break of the distribution transformer under the Dy11 connection mode; S5: Compare the monitoring value of each low voltage monitoring point with the constructed comparison value, specifically, subtract the monitoring value from the six comparison values ​​to obtain six offsets, the expressions of which are: Among them, m is the monitoring quantity; The expression of the comparison standard is: s i |<0.1; Among them, σ i Indicates the i-th offset, and records the number of monitoring points whose voltage values ​​meet the comparison criteria behind each positioning area; S6: Compare the number of monitoring points in the positioning area with the largest number of monitoring points whose voltage values ​​meet the comparison criteria behind the positioning area with the number of low-voltage monitoring points behind each positioning area. The positioning areas with the same number of monitoring points are the areas where faults occur.

2. A method for locating a single-phase disconnection fault in a distribution network according to claim 1, characterized in that: The data processing in step S3 includes normalization processing, and its expression is: m = [Ua, Ub, Uc] / 220; Among them, Ua is the phase A voltage value of the low voltage monitoring point, Ub is the phase B voltage value of the low voltage monitoring point, and Uc is the phase C voltage value of the low voltage monitoring point.

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