Method, system and equipment for judging fault section of direct current traction system and medium

Abstract

The invention discloses a method, a system, equipment and a medium for judging a fault section of a direct-current traction system, and relates to the technical field of track detection. Comprising the following steps: acquiring feeder current at two sides of a positive rail and two sides of a special return rail of a plurality of sections in the direct-current traction system, and determining a feeder current fault component phasor and Ig of each section according to the feeder current; determining a setting current value Iset according to the maximum amplitude Ig.max of the phasor sum of the feeder current fault component and the minimum If. Min of the total current fault component; comparing the amplitude Ig of the fault component phasor and Ig with a setting current value Iset; and obtaining a judgment result of the fault section according to a comparison result. According to the method, the positive electrode grounding fault section can be quickly and accurately positioned, the transition resistance tolerance and the identification sensitivity can be greatly improved, the influence of load current can be effectively avoided, and strict synchronous time synchronization requirements for data communication are avoided.

Description

Technical Field

[0001] The present invention relates to the field of track detection technology, and in particular to a method, system, equipment and medium for determining a fault section of a DC traction system. Background Art

[0002] With the rapid development of urban rail transit, many cities in China have popularized urban rail transit tools, which has greatly promoted regional economic development and social progress. The traction power supply system is the core component of the urban rail transit system, which mainly adopts the DC traction power supply system. Therefore, ensuring the safety of the DC traction system is the key to ensuring the stable operation of the urban rail transit system.

[0003] In the prior art, the fault section of the DC traction system is determined by the current difference method, and the specific process includes: obtaining the current between the positive feeder and the negative feeder, and calculating the current difference between the positive feeder and the negative feeder. In order to distinguish between the slight current difference under normal conditions and the significant current difference under fault conditions, it is necessary to set a current difference determination threshold. This threshold value is usually determined based on the maximum current difference during normal operation of the system (taking into account system losses and load imbalance), and multiplied by a safety factor (such as 1.4 times) to ensure that the protection action can be reliably triggered in the event of a fault. The current difference calculated in real time is compared with the set determination threshold. If the current difference is greater than the determination threshold, it is determined that a positive grounding fault has occurred.

[0004] The defects of the above-mentioned prior art are: the judgment result of the current difference method may be affected by the parameters of the DC traction system (such as load conditions, system losses, etc.). In the case of load imbalance or large system losses, the current difference may increase, increasing the risk of misjudgment of the fault section of the DC traction system. Summary of the invention

[0005] Based on this, it is necessary to provide a method, system, equipment and medium for determining the fault section of a DC traction system in response to the above technical problems.

[0006] An embodiment of the present invention provides a method for determining a fault section of a DC traction system, comprising:

[0007] Obtain the feeder currents on both sides of the positive rail and the dedicated return rail of multiple sections in the DC traction system, and determine the feeder current fault component phasor and I of each section based on the feeder current g ;

[0008] When the DC traction system is in a normal state, determine the maximum amplitude of the phase sum of the feeder current fault component |I g.max |; When the DC traction system is in a fault state, the DC traction system passes through the transition resistance R at the fault point f. g, the equivalent impedance Z on the left side of the fault point f eqL and the equivalent impedance Z to the right of the fault point f eqR Determine the minimum value of the total fault current component of the positive ground fault I f.min ;

[0009] According to the maximum amplitude |I g.max | and the minimum value of the total fault current component I f.min Determine the setting current value I used to determine the fault section location of the DC traction system set ;

[0010] The fault component phasor and I g The amplitude of |I g |With the set current value I set Compare; if the amplitude |I g |Amplitude less than the set current value|I set |, the section corresponding to the fault component is the normal section; if the amplitude |I g |Amplitude greater than or equal to the set current value|I set |, the segment corresponding to the fault component is the fault segment.

[0011] Optionally, the feeder current fault component phasor and I of each section are determined according to the feeder current. g , and its calculation formula is:

[0012]

[0013] in, is the fault component of the feeder current on the left side of the positive rail; is the fault component of the feeder current on the right side of the positive rail; It is the fault component of the feeder current on the left side of the dedicated return rail; It is the fault component of the feeder current on the right side of the dedicated return rail.

[0014] Optionally, determine the maximum amplitude of the phase sum of the feeder current fault component |I g.max |, the calculation formula is:

[0015]

[0016] Among them, I M It is the sum of the rated currents of all locomotives on the feeder.

[0017] Optionally, the minimum value I of the total fault component of the positive ground fault is determined f.min , which specifically include:

[0018] Determine the equivalent impedance Z on the left side of the fault point f eqL And the equivalent impedance Z on the right eqR, and its calculation formula is:

[0019]

[0020] According to the transition resistance R at the fault point f g , the equivalent impedance Z on the left eqL And the equivalent impedance Z on the right eqR Determine the amplitude I f , and its calculation formula is:

[0021]

[0022] Then the minimum value of the total current fault component I f.min The value range of is:

[0023]

[0024] Among them, Z eqL is the equivalent impedance on the left side of the fault point f, Z eqR is the equivalent impedance on the right side of the fault point f, U f0 is the normal state voltage of the fault point f before the fault, Z S1 is the equivalent impedance of traction substation 1, Z S2 is the equivalent impedance of traction substation 2, Z S3 is the equivalent impedance of traction substation 3, Z S4 is the equivalent impedance of traction substation 4, Z1 is the equivalent impedance of the contact rail in area A without locomotive, Z2 is the equivalent impedance of the contact rail in fault area B, Z3 is the equivalent impedance of the contact rail in area C with locomotive, and α is the ratio of the distance from the fault point f to the left side of the fault area B to the length of the fault area B.

[0025] Optionally, a set current value I for determining the location of a fault section of a DC traction system is determined. set include:

[0026] I set Not less than the component phase and amplitude of the current fault |I g The maximum value of |I g.max |,I set Less than the minimum value of the total current fault component I of the positive ground fault f.min , expressed as:

[0027]

[0028] The calculation formula for the set current value is:

[0029]

[0030] Among them, I f.min is the minimum value of the total fault current component, |I g.max| is the fault component phase and amplitude |I g The maximum value of | set is the set current value, I M It is the sum of the rated currents of all locomotives on the feeder.

[0031] The embodiment of the present invention further provides a DC traction system fault section determination system, comprising:

[0032] The current acquisition module is used to obtain the feeder currents on both sides of the positive rail and the dedicated return rail of multiple sections in the DC traction system, and determine the feeder current fault component phasor and I of each section according to the feeder current g ;

[0033] A processing module is used to determine the maximum amplitude value of the phase sum of the feeder current fault component when the DC traction system is in a normal state |I g.max |; When the DC traction system is in a fault state, the DC traction system passes through the transition resistance R at the fault point f. g , the equivalent impedance Z on the left side of the fault point f eqL and the equivalent impedance Z to the right of the fault point f eqR , determine the minimum value of the total fault current component of the positive ground fault I f.min ;

[0034] Preset module for calculating the maximum amplitude value|I g.max | and the minimum value of the total fault current component I f.min , determine the setting current value I used to determine the fault section location of the DC traction system set ;

[0035] Comparison module, used to compare the fault component phase of each section with I g The amplitude of |I g |With the set current value I set Compare; if the amplitude |I g |Amplitude less than the set current value|I set |, the section corresponding to the fault component is the normal section; if the amplitude |I g |Amplitude greater than or equal to the set current value|I set |, the segment corresponding to the fault component is the fault segment.

[0036] An embodiment of the present invention further provides a computer device, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the steps of the method for determining a fault section of a DC traction system are implemented.

[0037] An embodiment of the present invention further provides a storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the method for determining a fault section of a DC traction system are implemented.

[0038] Compared with the prior art, the DC traction system fault section determination method, system, device and medium provided by the embodiments of the present invention have the following beneficial effects:

[0039] The judgment result of the current difference method in the prior art may be affected by the parameters of the DC traction system (such as load conditions, system losses, etc.). In the case of unbalanced load or large system losses, the current difference may increase, increasing the risk of misjudgment of the fault section of the DC traction system.

[0040] The present invention determines the phasor sum of the feeder current fault components based on the feeder currents on both sides of the positive rail and the dedicated return rail of each section, and then determines the maximum amplitude when the DC traction system is in a normal state and the minimum total current fault component when the DC traction system is in a fault state; by comparing the maximum amplitude when in a normal state with the minimum total current fault component when in a fault state, the current change in the DC traction system is reflected to avoid the increase in current difference caused by large system loss; by using the transition resistor R g , equivalent impedance Z eqL and equivalent impedance Z eqR The combination of the three to determine the minimum value of the total current fault component of the positive grounding fault can solve the problem of load imbalance in the judgment process and reduce the occurrence of misjudgment of the fault section. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A diagram of a DC traction power supply system for straddle-type monorail transportation, providing a method for determining a fault section of a DC traction system in an embodiment;

[0042] Figure 2 A fault component equivalent model diagram of a DC traction system when a positive pole is grounded in a DC traction system fault section determination method provided in an embodiment;

[0043] Figure 3 A simplified equivalent model diagram of a fault component of a DC traction system when a positive pole is grounded in a method for determining a fault section of a DC traction system provided in an embodiment;

[0044] Figure 4 An equivalent model diagram of a DC traction system when a locomotive suddenly enters a method for determining a fault section of a DC traction system provided in an embodiment;

[0045] Figure 5The present invention is a flow chart of a fault section location algorithm of a method for determining a fault section of a DC traction system provided in an embodiment. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0047] In one embodiment, a method for determining a fault section of a DC traction system is provided, the method comprising:

[0048] 1. Equivalence model and feature analysis

[0049] 1.1. Equivalent model of DC traction system

[0050] DC traction power supply system for straddle-type monorail transportation Figure 1 As shown. Figure 1 In the figure, four traction substations and three sections (area A without locomotives, fault area B, and area C with locomotives) are shown. Current transformers are installed on both sides of the contact rails and dedicated return rails in each section, and the negative busbar of each traction substation is equipped with a 64D grounding protection device. A locomotive enters the right entrance of locomotive area C, and the fault point f of the positive pole of fault area B is connected to the transition resistor R g The present invention adopts the circuit superposition law to obtain the equivalent circuit diagrams of the DC traction system of straddle-type monorail transportation in the above two cases, and analyzes the fault components on both sides of the contact rail and the dedicated return rail of each section based on the equivalent circuit diagrams.

[0051] When only the fault point f at the positive pole of fault zone B is considered, the transition resistance R g When a ground fault occurs, the unidirectional conduction device in each traction substation 64D is actuated, and the short-circuit current flows into the negative busbar. According to the fault component principle, the fault component equivalent model is obtained, as shown in the figure. Figure 2 shown.

[0052] exist Figure 2 In the figure, Z1, Z2, and Z3 are the contact rail equivalent impedances of the non-locomotive area A, the fault area B, and the locomotive area C respectively; Z 11 , Z 21 , Z 31 They are the equivalent impedances of the dedicated return rails in the non-locomotive area A, the fault area B, and the locomotive area C; Z S1 , Z S2 , Z S3 , Z S4 are the equivalent impedances of traction substations 1, 2, 3, and 4 respectively; R gis the transition resistance of the fault point f of the positive pole of fault zone B to ground; Z M is the equivalent impedance of the locomotive; U f0 is the normal state voltage of the fault point f before the fault; I ALg+ ,I BLg+ ,I CLg+ They are the fault components of the left side of the contact rail current in the non-locomotive area A, fault area B, and locomotive area C; I ALg- ,I BLg- ,I CLg- They are the fault components of the current on the right side of the contact rail in the non-locomotive area A, the fault area B, and the locomotive area C; I ARg+ ,I BRg+ ,I CRg+ They are the fault components of the current on the left side of the dedicated return rail in the non-locomotive area A, the fault area B, and the locomotive area C; I ARg- ,I BRg- ,I CRg- They are the fault components of the current on the right side of the dedicated return rail in the non-locomotive area A, fault area B, and locomotive area C; I f is the fault component of the short-circuit current flowing into the fault point f; α is the ratio of the distance from the fault point f to the left side of the fault area B to the length of the fault area B.

[0053] When the positive pole is grounded, all 64D unidirectional diodes in the traction substation are turned on, making the two sides of the dedicated return rail of each section equal to zero potential. 11 , Z 21 , Z 31 There is no current in the branch, so it can be treated as an open circuit. Finally, the simplified equivalent model of the fault component is obtained, such as Figure 3 shown.

[0054] When only considering the sudden entry of a locomotive at the right entrance of locomotive area C, the direction of the load current measured on the right side of the contact rail and the dedicated return rail of locomotive area C changes, but the magnitude remains unchanged. The direction and magnitude of the load current measured in other sections and on the left side of locomotive area C remain unchanged. The corresponding DC traction system equivalent model is as follows: Figure 4 As shown. Among them, U S1 , U S2 , U S3 , U S4 are the equivalent voltage sources of traction substations 1, 2, 3, and 4 respectively; I AL+ ,I BL+ ,I CL+ They are the current on the left side of the contact rail in the section without locomotive A, the fault zone B, and the locomotive zone C; I AR+ ,I BR+ ,I CR+ They are the current on the right side of the contact rail in the non-locomotive area A, the fault area B, and the locomotive area C; I AL- ,I BL-,I CL- They are the current on the left side of the dedicated return rail in the non-locomotive area A, the fault area B, and the locomotive area C; I AR- ,I BR- ,I CR- They are the currents on the right side of the dedicated return rails in the non-locomotive area A, the fault area B, and the locomotive area C; I A ,I B ,I C are the load currents flowing through the locomotive-free area A, the fault area B, and the locomotive area C; I S4 It's U S4 The current passing through the branch; Z M The dotted line is the position of the locomotive before it enters the locomotive area C; Z M The solid line indicates that the locomotive enters the locomotive area C.

[0055] 1.2. Characteristics of current fault components during positive pole grounding fault

[0056] In the case of a positive ground fault, based on Figure 3 The characteristics of the current fault components on both sides of the positive rail and the dedicated return rail in the locomotive-free area A, the fault area B, and the locomotive area C are analyzed.

[0057] 1. No-Motorcycle Area A

[0058] according to Figure 3 The expressions of the current fault components on both sides of the positive rail and the dedicated return rail in the locomotive-free area A can be obtained, as shown in formula (1).

[0059]

[0060] In the formula Represents the sampled value obtained by sampling X.

[0061] According to formula (1), the sum of the phasors of the current fault components on both sides of the positive rail and the dedicated return rail in the locomotive-free area A is 0, as shown in formula (2).

[0062]

[0063] 2. Fault Area B

[0064] according to Figure 3 The expressions of the current fault components on both sides of the positive rail and the dedicated return rail in fault zone B can be obtained as shown in formula (3).

[0065]

[0066] According to formula (3), the sum of the current fault components on both sides of the positive rail and the dedicated return rail in fault area B is I f , is the total fault component current, as shown in formula (4).

[0067]

[0068] Figure 3 The equivalent impedance on the left side of the fault point f is Z eqL , the equivalent impedance on the right is Z eqR , and their sizes are shown in formula (5).

[0069]

[0070] according to Figure 3 The total current fault component I can be obtained by using formula (5): f , as shown in formula (6).

[0071]

[0072] Z S1 , Z S2 , Z S3 , Z S4 , Z1, Z2, Z3, Z M The difference in size is not big and small, and the value range of α is between 0 and 1. According to formula (5), Z eqL and Z eqR It is inductive and has a small amplitude. Therefore, when the positive grounding fault is not metallic grounding, I f The amplitude is basically determined by the transition resistance R g Influence.

[0073] 3. Locomotive Area C

[0074] according to Figure 3 The expressions of the current fault components on both sides of the positive rail and the dedicated return rail in the locomotive area C can be obtained, as shown in formula (7).

[0075]

[0076] According to formula (5), the sum of the phasors of the current fault components on both sides of the positive rail in the locomotive area C and on both sides of the dedicated return rail is 0, as shown in formula (8).

[0077]

[0078] 1.3. Characteristics of current fault components when a locomotive suddenly enters

[0079] In the two cases where the locomotive does not enter or suddenly enters the locomotive area C, based on Figure 4 Analyze the load current on both sides of the positive rail and the dedicated return rail in section A, fault area B, and locomotive area C, and then calculate the corresponding current fault components.

[0080] 1. Load current when the locomotive does not enter the locomotive area C

[0081] The situation where the locomotive does not enter the locomotive area C is as follows Figure 4 The locomotive position shown by the dotted line in the middle can be used to obtain the load current on both sides of the positive rail and the dedicated return rail in the locomotive-free area A, the fault area B, and the locomotive area C. The load current expression on both sides of the positive rail and the dedicated return rail in the locomotive-free area A is shown in formula (9).

[0082]

[0083] The load current expressions on both sides of the positive rail and the dedicated return rail in fault area B are shown in formula (10).

[0084]

[0085] The load current expressions on both sides of the positive rail and the dedicated return rail in the locomotive area C are shown in formula (11).

[0086]

[0087] 2. Load current when the locomotive suddenly enters locomotive area C

[0088] The situation where a locomotive suddenly enters locomotive zone C is as follows Figure 4 The solid line in the middle shows the locomotive position. The load currents on both sides of the positive rail and the dedicated return rail in the locomotive-free zone A, the fault zone B, and the locomotive zone C can be obtained. The load currents on both sides of the positive rail and the dedicated return rail in the locomotive-free zone A are the same as those in equation (9). The load currents on both sides of the positive rail and the dedicated return rail in the fault zone B are the same as those in equation (10). The load current expressions on both sides of the positive rail and the dedicated return rail in the locomotive zone C are shown in equation (12).

[0089]

[0090] 3. Characteristics of current fault components when a locomotive suddenly enters locomotive zone C

[0091] According to equations (9) to (12), the current fault components on both sides of the positive rail and the dedicated return rail in the non-locomotive area A, the fault area B, and the locomotive area C can be calculated when the locomotive suddenly enters the locomotive area C.

[0092] The current fault components on both sides of the positive rail and the dedicated return rail in the locomotive-free area A and the current fault components on both sides of the positive rail and the dedicated return rail in the fault area B are shown in formula (13).

[0093]

[0094] The current fault components on both sides of the positive rail in locomotive area C and on both sides of the dedicated return rail are shown in formula (14).

[0095]

[0096] According to equations (13) and (14), it can be concluded that the sum of the phasors of the current fault components on both sides of the positive rail and the dedicated return rail in the locomotive-free area A, the fault area B, and the locomotive area C are all 0, as shown in equation (15).

[0097]

[0098] 1.4. Analysis of current fault component characteristics

[0099] 1. Consider only positive ground fault

[0100] According to the analysis in Section 1.2, when only the positive grounding fault (fault state) is considered, the phasor sum of the current fault components on both sides of the positive rail and the dedicated return rail in the locomotive-free area A and the locomotive area C is equal to 0, while the phasor sum of the current fault components on both sides of the positive rail and the dedicated return rail in the fault area B is I f .

[0101] Second, only consider the sudden entry of locomotives

[0102] According to the analysis in Section 1.3, when only the locomotive suddenly enters (normal state), the phasor sum of the current fault components on both sides of the positive rail and the dedicated return rail in the locomotive-free area A, the fault area B, and the locomotive area C are all equal to 0.

[0103] 3. Positive grounding fault and locomotive suddenly driving in at the same time

[0104] When the positive pole grounding fault and the locomotive suddenly enter at the same time, according to the circuit superposition law, the phasor sum of the current fault components on both sides of the positive rail and the dedicated return rail in the locomotive-free area A and the locomotive area C is equal to 0, and the phasor sum of the current fault components on both sides of the positive rail and the dedicated return rail in the fault area B is I f .

[0105] Based on the above three situations, we can know the phasor and amplitude characteristics of the current fault component on both sides of the positive rail and the dedicated return rail in the locomotive-free area A, the fault area B, and the locomotive area C:

[0106] (1) As long as a positive ground fault occurs, the phasor sum of the current fault components on both sides of the positive rail and the dedicated return rail in fault zone B is I f , while the phasor sum of the current fault components on both sides of the positive rail and the dedicated return rail in other sections is 0.

[0107] (2) Total current fault component I f The amplitude is relatively large, but is affected by the transition resistance.

[0108] (3) In normal state or when a locomotive suddenly enters, the phasor sum of the current fault components on both sides of the positive rail and the dedicated return rail in all sections is 0.

[0109] 2. Principle of locating the positive grounding fault section

[0110] 2.1. Section positioning principle

[0111] It can be seen from Section 1.4 that only in the section where the positive pole grounding fault occurs, the phasor and amplitude of the current fault component on both sides of the positive rail and the dedicated return rail are greater than 0, and the phasor and amplitude of the current fault component on both sides of the positive rail and the dedicated return rail in other sections are equal to 0. Therefore, the present invention uses the phasor and amplitude of the feeder current fault component as a criterion for locating the positive pole grounding fault section.

[0112] First, calculate the current fault component phasor and I on both sides of the positive rail and the dedicated return rail of the section. g , compare its amplitude |I g | and the preset set current value I set , when |I g |≥I set , then the section is judged to be a positive grounding fault section, that is, a fault section. When |I g | set , then the section is judged to be a normal section. Therefore, the fault section location criterion is shown in formula (16).

[0113]

[0114] 2.2 Principle Implementation

[0115] From formula (16), we can see that we need to know I Lg+ ,I Rg+ ,I Lg- ,I Rg- ,I set Specific values ​​can be used for comparison and judgment, among which I Lg+ and I Rg+ It can be calculated using the current collected by the current transformers on both sides of the positive rail of the section, I Lg- and I Rg- It can be calculated by using the current collected by the current transformers on both sides of the section-specific return rail, and the set current value I set The size needs to be determined through detailed analysis.

[0116]

[0117] in They are the sampling values ​​of the left side of the positive rail, the right side of the positive rail, the left side of the dedicated return rail, and the right side of the dedicated return rail at time t; ​They are the sampling values ​​of the current transformers on the left side of the positive rail of the section, the right side of the positive rail, the left side of the special return rail of the section, and the right side of the special return rail in the power frequency cycle before time t; T is the power frequency cycle.

[0118] I set The selection of must adhere to a principle, that is, to ensure that the DC traction system is not misjudged when it is normal and not rejected when it fails. Therefore, two points are considered. First, under normal conditions, the load current fluctuation and current transformer sampling error will cause the current fault component phasor and amplitude on both sides of the section positive rail and the dedicated return rail |I g |Not 0, I set To be greater than its maximum value |I g.max |, to ensure that the fault section location program does not misjudge; second, I set It should not be greater than the minimum value of the total current fault component of the positive grounding fault I f.min , to ensure that the fault section location program does not reject the judgment, so I set The value of is shown in formula (17).

[0119]

[0120] During normal operation, the transmission error between current transformers is about 0.25%, and the maximum load fluctuation current is the sum of the rated currents of all locomotives on the feeder I M , we can calculate |I g.max |, as shown in formula (18).

[0121]

[0122] When the positive pole is grounded, according to formula (6), I f With transition resistance R g Closely related, the minimum value of the total current fault component I f.min The value range of is shown in formula (19).

[0123]

[0124] In order to ensure the feasibility of the algorithm and its ability to withstand a certain transition resistance, I f.min Take 1.2×I set , while I set The value of |I g.max | and considering a certain margin, the reliability coefficient is 1.2, then I set The value of is shown in formula (20). The maximum transition resistance value that the algorithm of the present invention can tolerate is shown in (21).

[0125]

[0126] Each section is equipped with a fault section locating device. Its principle and specific process are as follows: Figure 5 As shown, it can be divided into four steps:

[0127] (1) According to formula (20), the set current value I of the fault section locating device is set set .

[0128] (2) The fault section locating device collects the feeder current in real time from the current transformers on both sides of the positive rail and the dedicated return rail in this section, and calculates the phasor of the feeder current fault component and I g and amplitude |I g |.

[0129] (3) Real-time comparison of the phase and amplitude of the feeder current fault component |I g |Amplitude of the set current value|I set |, if |I g |<|I set |, the segment is judged as a normal segment. If |I g |≥|I set |, the segment is judged as a faulty segment.

[0130] (4) For sections that are judged to be faulty, the faulty section locating device sends a tripping command to the circuit breakers on both sides of the section to isolate the faulty section, and transmits the locating result to the urban rail transit dispatching command system. The rail transit train dispatcher then orders the maintenance personnel to quickly eliminate and repair the section fault and resume operations.

[0131] 3. Conclusion

[0132] The present invention analyzes the positive rail grounding fault of the straddle-type monorail transportation DC traction system and the feeder current fault component when the locomotive suddenly enters, and draws the following conclusions:

[0133] (1) The equivalent model of the fault component when the positive pole of the DC traction system is grounded and the equivalent model of the DC traction system when a locomotive suddenly enters are respectively built. The phasor and characteristics of the current fault components on both sides of the positive rail and the dedicated return rail of each section are analyzed under three conditions (only considering the positive pole grounding fault, only considering the sudden entry of the locomotive, and considering both at the same time). The present invention proposes a fault section locating method based on the phasor sum of the section current fault components.

[0134] (2) Each section is equipped with a fault section locating device, which collects the feeder current in real time from the current transformers on both sides of the positive rail and the dedicated return rail in this section, and then calculates the phasor and amplitude of the current fault component in this section, compares it with the set value, and then determines the state of the section. This method can accurately locate the fault section under different fault point locations and different transition resistances. The phasor and amplitude of the current fault component are slightly affected by the fault point location and can be ignored, but are greatly affected by the transition resistance. However, it can tolerate a transition resistance of up to 500Ω. At the same time, it has strong noise resistance and can effectively avoid the impact of shock loads.

[0135] (3) Compared with the prior art, the fault section locating method proposed in the present invention has better locating effect, can tolerate larger transition resistance, and has higher algorithm sensitivity. It is not only applicable to grounding faults in DC traction systems of straddle-type monorail transportation, but also has reference significance for locating fault sections in urban rail transportation such as maglev and subway.

[0136] Based on the same inventive concept, the present invention also provides a DC traction system fault section determination system, comprising:

[0137] The current acquisition module is used to obtain the feeder currents on both sides of the positive rail and the dedicated return rail of multiple sections in the DC traction system, and determine the feeder current fault component phasor and I of each section according to the feeder current g ;

[0138] A processing module is used to determine the maximum amplitude value of the phase sum of the feeder current fault component when the DC traction system is in a normal state |I g.max |; When the DC traction system is in a fault state, the DC traction system passes through the transition resistance R at the fault point f. g , the equivalent impedance Z on the left side of the fault point f eqL and the equivalent impedance Z to the right of the fault point f eqR , determine the minimum value of the total fault current component of the positive ground fault I f.min ;

[0139] Preset module for calculating the maximum amplitude value|I g.max | and the minimum value of the total fault current component I f.min , determine the setting current value I used to determine the fault section location of the DC traction system set ;

[0140] Comparison module, used to compare the fault component phase of each section with I g The amplitude of |I g |With the set current value I set Compare; if the amplitude |I g |Amplitude less than the set current value|I set|, the section corresponding to the fault component is the normal section; if the amplitude |I g |Amplitude greater than or equal to the set current value|I set |, the segment corresponding to the fault component is the fault segment.

[0141] Furthermore, the present invention also provides a computer device, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the steps of the method for determining a fault section of a DC traction system are implemented. The specific implementation method can be found in the method embodiment, which will not be described in detail here.

[0142] Furthermore, the present invention also provides a storage medium on which a computer program is stored, such as a memory containing instructions, and the instructions can be executed by a processor of a computer device to complete the above method. For example, the non-temporary computer-readable storage medium can be a ROM, a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, and an optical data storage device. When the computer program is executed by the processor, the steps of the method for determining the fault section of the DC traction system are implemented. The specific implementation method can be referred to the method embodiment, which will not be repeated here.

[0143] The above-mentioned embodiments only express several implementation methods of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A method for determining a fault section of a DC traction system, characterized in that: include: Obtain the feeder currents on both sides of the positive rail and the dedicated return rail of multiple sections in the DC traction system, and determine the feeder current fault component phasor and I of each section based on the feeder current g ; When the DC traction system is in a normal state, determine the maximum amplitude of the phase sum of the feeder current fault component |I g.max |; When the DC traction system is in a fault state, the DC traction system passes through the transition resistance R at the fault point f. g , the equivalent impedance Z on the left side of the fault point f eqL and the equivalent impedance Z to the right of the fault point f eqR , determine the minimum value of the total fault current component of the positive ground fault I f.min ; According to the maximum amplitude |I g.max | and the minimum value of the total fault current component I f.min , determine the setting current value I used to determine the fault section location of the DC traction system set ; The fault component phasor and I g The amplitude of |I g |With the set current value I set Compare; if the amplitude |I g |Amplitude less than the set current value|I set |, the section corresponding to the fault component is the normal section; if the amplitude |I g |Amplitude greater than or equal to the set current value|I set |, the segment corresponding to the fault component is the fault segment.

2. A method for determining a fault section of a DC traction system according to claim 1, characterized in that: The method of determining the fault component phase of the feeder current of each section and I g , and its calculation formula is: in, is the fault component of the feeder current on the left side of the positive rail; is the fault component of the feeder current on the right side of the positive rail; It is the fault component of the feeder current on the left side of the dedicated return rail; It is the fault component of the feeder current on the right side of the dedicated return rail.

3. A method for determining a fault section of a DC traction system according to claim 1, characterized in that: The determination of the maximum amplitude value of the phase sum of the feeder current fault component |I g.max |, the calculation formula is: Among them, I M It is the sum of the rated currents of all locomotives on the feeder.

4. A method for determining a fault section of a DC traction system according to claim 1, characterized in that: The minimum value I of the total current fault component of the positive pole grounding fault is determined f.min , which specifically include: Determine the equivalent impedance Z on the left side of the fault point f eqL And the equivalent impedance Z on the right eqR , and its calculation formula is: According to the transition resistance R at the fault point f g , the equivalent impedance Z on the left eqL And the equivalent impedance Z on the right eqR Determine the amplitude I f , and its calculation formula is: Then the minimum value of the total current fault component I f.min The value range of is: Among them, Z eqL is the equivalent impedance on the left side of the fault point f, Z eqR is the equivalent impedance on the right side of the fault point f, U f0 is the normal state voltage of the fault point f before the fault, Z S1 is the equivalent impedance of traction substation 1, Z S2 is the equivalent impedance of traction substation 2, Z S3 is the equivalent impedance of traction substation 3, Z S4 is the equivalent impedance of traction substation 4, Z1 is the equivalent impedance of the contact rail in area A without locomotive, Z2 is the equivalent impedance of the contact rail in fault area B, Z3 is the equivalent impedance of the contact rail in area C with locomotive, and α is the ratio of the distance from the fault point f to the left side of the fault area B to the length of the fault area B.

5. A method for determining a fault section of a DC traction system according to claim 1, characterized in that: The setting current value I for determining the fault section location of the DC traction system is determined set include: I set Not less than the component phase and amplitude of the current fault |I g The maximum value of |I g.max |,I set Less than the minimum value of the total current fault component I of the positive ground fault f.min , expressed as: The calculation formula for the set current value is: Among them, I f.min is the minimum value of the total fault current component, |I g.max | is the fault component phase and amplitude |I g The maximum value of | set is the set current value, I M It is the sum of the rated currents of all locomotives on the feeder.

6. A DC traction system fault section determination system, characterized in that: include: The current acquisition module is used to obtain the feeder currents on both sides of the positive rail and the dedicated return rail of multiple sections in the DC traction system, and determine the feeder current fault component phasor and I of each section according to the feeder current g ; A processing module is used to determine the maximum amplitude value of the phase sum of the feeder current fault component when the DC traction system is in a normal state |I g.max |; When the DC traction system is in a fault state, the DC traction system passes through the transition resistance R at the fault point f. g , the equivalent impedance Z on the left side of the fault point f eqL and the equivalent impedance Z to the right of the fault point f eqR , determine the minimum value of the total fault current component of the positive ground fault I f.min ; Preset module for calculating the maximum amplitude value|I g.max | and the minimum value of the total fault current component I f.min , determine the setting current value I used to determine the fault section location of the DC traction system set ; Comparison module, used to compare the fault component phase of each section with I g The amplitude of |I g |With the set current value I set Compare; if the amplitude |I g |Amplitude less than the set current value|I set |, the section corresponding to the fault component is the normal section; if the amplitude |I g |Amplitude greater than or equal to the set current value|I set |, the segment corresponding to the fault component is the fault segment.

7. A computer device comprising a memory and a processor, wherein a computer program is stored in the memory, wherein: When the processor executes the computer program, the steps of the method for determining a faulty section of a DC traction system according to any one of claims 1 to 5 are implemented.

8. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for determining a fault section of a DC traction system according to any one of claims 1 to 5 are implemented.

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