A fault locating method for AT single-wire power supply system

Abstract

The application discloses a fault positioning method for an AT single-wire power supply system, which collects analog quantity information of key nodes through an existing fault distance measurement system in each building, first judges the fault type through the T-line current and the F-line current in each building, then checks and normalizes the key analog quantity data, and finally calculates the fault distance according to the core algorithm of the fault positioning method of the AT single-wire power supply system, and supports the correction of the fault distance by adjusting the line impedance parameters after the distance measurement result is obtained. The method can accurately realize the fault positioning of the AT single-wire power supply system, greatly improves the accuracy compared with the conventional on-load current ratio method, and has certain engineering applicability, thereby providing a thought for the future fault of the AT single-wire power supply system.

Description

Technical Field

[0001] This invention belongs to the field of relay protection for traction power supply systems, and in particular relates to a fault location method for AT single-line power supply systems. Background Technology

[0002] The AT single-line power supply system is a relatively special power supply method. Because there is no parallel connection at the end of the line as in the double-line operation mode, the fault location method based on the ratio of up-down current and cross-connection current cannot be used. When the contact wire or the positive feeder is short-circuited, the presence of the autotransformer also precludes the use of linear reactance fault location. Currently, the mainstream fault location method for the AT single-line power supply system relies on the pull-up current ratio. However, the derivation process neglects the influence of the AT transformer leakage reactance and external circuit characteristics, as well as the different materials of the contact wire and the positive feeder, resulting in significant uncontrollable fault location errors. While introducing a Q-value for segmented calculation can eliminate these errors, the Q-value is often calculated back from field fault data in practice. However, the introduction of the Q-value lacks a solid theoretical basis, and the data required for the field calculation is limited to only a few points, requiring further verification of its applicability across the entire line. Therefore, a novel fault location method is urgently needed for the AT single-line power supply system. Summary of the Invention

[0003] In view of this, the present invention aims to propose a fault location method for AT single-line power supply systems, and to provide a scientific, reasonable, fast and accurate contact wire feeder relay protection method. This method is a fault location method for AT single-line power supply systems, which can achieve fast and accurate location under AT single-line power supply mode.

[0004] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0005] A fault location method for an AT single-wire power supply system, characterized by comprising at least one of the following steps:

[0006] S1. In the AT single-line power supply system, analog data of each important node is collected through the fault location system of the traction substation, AT substation and section substation.

[0007] S2. Determine whether it is a TF fault based on the collected analog data. After ruling out TF line faults, further distinguish whether it is a TR fault or an FR fault based on the angle between the T line and F line data.

[0008] S3. In step S2, if it is not a TF fault, the collected analog data will be verified and the angle will be normalized.

[0009] S4. By using the voltage matrix balance equation, the relationship between the fault distance and the analog quantities of each node is calculated, and the fault location of the AT single-line system is completed.

[0010] Furthermore, after step S3, an asymmetry coefficient between the T-line and the F-line is introduced.

[0011] Furthermore, in step S1, the fault location system refers to a system in which one fault location device is installed in each of the traction substation, AT substation, and section substation, and the devices are connected through the fault location channel.

[0012] Furthermore, in step S1, the analog data of each important node includes the T-line current, F-line current, T-line voltage, and F-line voltage.

[0013] Furthermore, in step S2, the specific details are as follows:

[0014] By the difference between the T-line current and the F-line current of the traction substation The sum of the T-line current and F-line current of each station Comparing the two, when If the fault is detected in time, it is determined to be a TF fault; otherwise, it is determined to be a TR or FR fault, where:

[0015]

[0016]

[0017] If the fault is near-end fault, it needs to be verified again. Then the diagnosis is changed to TR fault, if Then the diagnosis is changed to FR fault.

[0018] Furthermore, after determining that it is a TR fault or an FR fault, if >1.1 If the condition is met, it is determined to be a TR fault; otherwise, it is determined to be an FR fault.

[0019] Furthermore, in step S3, the analog data is verified as follows: If a TR fault is detected, the following checks are performed: The verification is then complete; the same applies to FR and TR faults.

[0020] Furthermore, in step S3, the angle normalization is as follows: set the angle of the traction T-line current to zero, and then rotate the angles of the remaining analog quantities based on the T-line current to complete the normalization.

[0021] Furthermore, in step S4, the relationship between the fault distance and the analog quantities of each node is calculated as follows: when the TF line is faulty, the linear reactance method is selected for distance measurement, while when the TR / FR is faulty, the voltage and current combined distance measurement method is used.

[0022] Furthermore, this solution discloses a computer-readable storage medium storing a computer program, which, when executed by a processor, implements a fault location method for an AT single-line power supply system.

[0023] Compared with existing technologies, the fault location method for AT single-line power supply systems described in this invention has the following advantages:

[0024] (1) The fault location method for AT single-line power supply system described in this invention solves the ranging error caused by the leakage reactance of the autotransformer and the external characteristics of the circuit;

[0025] (2) The fault location method for AT single-line power supply system described in this invention does not need to introduce the Q value, which has no theoretical basis, and does not need to calculate the Q value based on the fault data on site.

[0026] (3) The fault location method for AT single-line power supply system described in this invention takes into account the different materials of the contact wire and the positive feeder, and introduces the parameter of the asymmetry between the T line and the F line.

[0027] (4) The fault location method for AT single-line power supply system described in this invention has reserved adjustable parameters on both sides of the line impedance and the line impedance angle, which can correct the distance measurement error based on the on-site fault data or operation data. Attached Figure Description

[0028] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0029] Figure 1 The analog quantities and positive current directions of important nodes in the TF fault network topology are plotted.

[0030] Figure 2 Equivalent model diagrams of each circuit in the traction power supply system;

[0031] Figure 3 The analog quantities and positive current directions of important nodes in the TR fault network topology are shown in the diagram.

[0032] Figure 4 Flowchart of fault location method for AT single-line power supply system. Detailed Implementation

[0033] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0034] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0035] A fault location method for an AT single-wire power supply system includes the following steps:

[0036] (1) In the AT single-line power supply system, analog data of each important node is collected through the fault location system of the traction substation, AT substation and section substation.

[0037] (2) Determine whether it is a TF fault based on the collected analog data. After eliminating the TF line fault, distinguish whether it is a TR fault or an FR fault based on the angle between the T line and the F line data.

[0038] (3) After completing the above steps, if it is not a TF fault, the collected analog data should be verified and the angle normalized.

[0039] (4) Due to the different materials of T-line and F-line, an asymmetry coefficient between T-line and F-line is introduced.

[0040] (5) The relationship between the fault distance and the analog quantities of each node is calculated by using the voltage matrix balance equation.

[0041] (6) The above steps can be used to complete the fault location of the AT single-line system. After the correct result is obtained, this method also supports adjusting the line parameters to complete the error correction.

[0042] Furthermore, the fault location system in (1) refers to a system in which one fault location device is installed in each of the traction depot, AT depot, and section depot, and the devices are connected through the fault location channel.

[0043] Furthermore, the analog data collected by the fault location system in (1) mainly includes the T-line current, F-line current and T-line voltage, F-line voltage.

[0044] Furthermore, the step (2) of determining the fault type based on the collected analog data refers to the difference between the current of the T-line and the F-line of the traction substation, i.e.: The sum of the T-line current and F-line current of each station is: Comparing the two, when If the fault is detected, it is determined to be a TF fault; otherwise, it is determined to be a TR or FR fault.

[0045]

[0046]

[0047] If it is a near-end fault, judging it as a TF fault in (2) may result in an error. It needs to be verified again. Then the diagnosis is changed to TR fault, if Then the diagnosis is changed to FR fault.

[0048] Furthermore, the step (3) of verifying the analog data refers to: if it is a TR fault, determining... The verification is now complete.

[0049] Furthermore, the specific steps of angle normalization in (3) are as follows: In the project, the data collected by the fault location system are all based on the voltage data of the institute. The data between institutes lacks angular correlation, so angle normalization is required to unify the data across the entire line. When a TR fault is identified and the data verification is completed, the F line is selected as the research object, and the angle of the data in each institute is subtracted from the angle of the corresponding F line in each institute, where angle is the angle function.

[0050] ; ;

[0051] ; ;

[0052] ; ;

[0053] ; ;

[0054] ; ;

[0055] Then, using the angle of the T-line of the traction station as a reference, the angles of the three analog data points are normalized.

[0056] ; ;

[0057] ; ;

[0058] ; ;

[0059] ; ;

[0060] ; ;

[0061] Furthermore, step (5) calculates the relationship between the fault distance and the analog quantities of each node. When the fault is on the TF line, for example... Figure 1 As shown, the linear reactance method is used for distance measurement:

[0062]

[0063] In the formula: , The normalized bus voltages of the traction substation's T-line and F-line are given. , Here, imag represents the normalized currents of the T-line and F-line of the traction substation, and imag is the reactance function. The unit reactance during TF fault. This represents the distance to the fault.

[0064] Furthermore, in step (5), the relationship between the fault distance and the analog quantities of each node is calculated. When the fault is TR or FR, the voltage-current combined ratio distance measurement method is used. Figure 2 As shown, the line parameters can be equivalently modeled as the contact network-ground loop, track-ground loop, and positive feeder-ground loop, with the self-impedance structure of the a-th loop. The mutual impedance structure between the a-th and b-th loops .by Figure 3 Taking a fault as an example, the equations for the line parameter matrix, voltage and current matrix are as follows:

[0065] ; ;

[0066] ; ;

[0067] From the voltage matrix balance equation, we can obtain:

[0068]

[0069] Normalized data was used in the calculation. Further analysis based on the voltage-current relationship between the downlink T-line and F-line yielded the following results:

[0070]

[0071] In the formula, * represents the analog quantity normalized to the angle, where , where real is a function that takes the real part. and This is the asymmetry coefficient between line T and line F.

[0072] When a TR fault is detected , ,

[0073] When the fault is identified as FR (Frequency Fault) , .

[0074] In the formula, This refers to the line impedance parameter, which is an adjustable parameter consisting of two parts: impedance magnitude and impedance angle. The parameter can be adjusted according to the actual site conditions.

[0075] Furthermore, in step (6), after obtaining the correct result, this method also supports adjusting the line parameters to complete the error correction. Since the actual on-site values ​​are calculated by the design institute, and due to factors such as on-site construction and the zigzag arrangement of the contact network, the calculation of the values ​​inevitably has some deviations. Therefore, after obtaining the correct result... We can substitute these values ​​back into the above equations, and by using the fault data and fault distance to solve a system of two linear equations in two variables, we can obtain the actual line parameters and line impedance angle. Based on operational experience, the inverse solution values ​​are often very close to the line parameters theoretically calculated by the design institute.

[0076] Those skilled in the art will recognize that the units and method steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0077] In the several embodiments provided in this application, it should be understood that the disclosed methods and systems can be implemented in other ways. For example, the division of units described above is merely a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. The aforementioned units may or may not be physically separated. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiments of the present invention according to actual needs.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

[0079] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A fault location method for an AT single-line power supply system, characterized in that, Includes at least one of the following steps: S1. In the AT single-line power supply system, analog data of each important node is collected through the fault location system of the traction substation, AT substation and section substation. S2. Determine whether it is a TF fault based on the collected analog data. After ruling out TF line faults, further distinguish whether it is a TR fault or an FR fault based on the angle between the T line and F line data. S3. In step S2, if it is not a TF fault, the collected analog data will be verified and the angle will be normalized. S4. By using the voltage matrix balance equation, the relationship between the fault distance and the analog quantities of each node is calculated, and the fault location of the AT single-line system is completed. In step S2, the specific details are as follows: By the difference between the T-line current and the F-line current of the traction substation The sum of the T-line current and F-line current of each station Comparing the two, when If the fault is detected in time, it is determined to be a TF fault; otherwise, it is determined to be a TR or FR fault, where: ； ； If the fault is near-end fault, it needs to be verified again. Then the diagnosis is changed to TR fault, if Then the diagnosis is changed to FR fault; After determining that it is a TR fault or an FR fault, if >1.1 If it is true, it is determined to be a TR fault; otherwise, it is determined to be an FR fault. In step S3, the analog data is verified as follows: If it is a TR fault, determine... The verification is then complete; the same logic applies to FR and TR faults. In step S3, the angle normalization is as follows: set the angle of the traction T-line current to zero, and then rotate the angles of the other analog quantities based on the T-line current to complete the normalization. It has reserved adjustable parameters on both sides of the line impedance and the line impedance angle, which can correct the ranging error based on the on-site fault data or operation data.

2. The fault location method for an AT single-line power supply system according to claim 1, characterized in that, After step S3, the asymmetry coefficient between the T-line and the F-line is introduced.

3. The fault location method for an AT single-line power supply system according to claim 1, characterized in that: In step S1, the fault location system refers to a system in which one fault location device is installed in each of the traction substation, AT substation, and section substation, and the devices are connected through the fault location channel.

4. The fault location method for an AT single-line power supply system according to claim 1, characterized in that, In step S1, the analog data of each important node includes the T-line current, F-line current, T-line voltage, and F-line voltage.

5. A fault location method for an AT single-line power supply system according to claim 1, characterized in that, In step S4, the relationship between the fault distance and the analog quantities of each node is calculated as follows: when the TF line is faulty, the linear reactance method is selected for distance measurement, while when the TR / FR is faulty, the voltage and current combined distance measurement method is used.

6. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by the processor, it implements the fault location method for an AT single-line power supply system as described in any one of claims 1-5.

Images