Method for locating leakage fault of magnetic levitation transportation traction power supply system and leakage protection method

Abstract

The application discloses a kind of magnetic levitation traffic traction power supply system leakage fault locating method, comprising: every one substation of traction power supply system is divided into independent four power supply sections according to uplink and downlink line and the abutment relationship with adjacent substation;If the sum of the through ground current of two power supply sections in a one-way line power supply section abutment pair between adjacent two substations is greater than zero, it is confirmed that there is leakage in the power supply section range of the one-way line power supply section abutment pair.The leakage fault locating method of the application can accurately lock the specific one-way line power supply section abutment pair where the leakage fault point is located by judging whether the sum of the through ground current of two power supply sections in a one-way line power supply section abutment pair between adjacent two substations is greater than zero, which lays a technical foundation for subsequent targeted step-by-step power-off protection and further determination of the accurate position of the leakage fault point.

Description

Technical Field

[0001] This invention relates to the field of traction power supply systems for medium and low speed maglev transportation, and more specifically, to a method for locating leakage faults and a method for protecting against leakage in maglev transportation traction power supply systems. Background Technology

[0002] The traction power supply system for medium- and low-speed maglev trains adopts a power supply method where DC 1500 V positive rails are insulated and laid on both sides of the running beam, and negative rails return current. To detect DC positive grounding faults, each substation is equipped with a DC grounding protection device (referred to as a 64D cabinet), installed between the negative busbar and the ground. The voltage between these two points is monitored to determine if a fault has occurred. When the DC positive terminal is short-circuited to the ground (in maglev trains, the DC positive terminal is short-circuited to the F-rail), the voltage between the ground and the negative busbar increases, triggering the DC grounding protection device to issue a protection signal.

[0003] Because the grounding wires of the entire power supply system are electrically connected, and the negative busbars of the up and down lines of each substation are electrically connected, if a DC grounding fault occurs on any line, the DC grounding protection device near the fault point can detect the voltage difference and trigger the protection action, thereby causing multiple substations to trip, expanding the power outage area, causing a major operational accident, and resulting in a wide range of fault investigation, heavy maintenance workload, and significant impact.

[0004] Existing grounding leakage protection devices or methods have not yet achieved the functions of preliminary location of leakage fault points and targeted step-by-step power outage protection, nor have they achieved the function of precise location of leakage fault points. Summary of the Invention

[0005] In response to at least one defect or improvement requirement in the prior art mentioned in the background section, the present invention provides a method for locating leakage faults and a method for protecting against leakage in a maglev transportation traction power supply system. This method is used to at least achieve preliminary location of the leakage fault point, laying a technical foundation for subsequent targeted step-by-step power outage protection and further determining the precise location of the leakage fault point.

[0006] In a first aspect, the present invention provides a method for locating leakage faults in a maglev transportation traction power supply system, comprising:

[0007] Each substation of the traction power supply system is divided into four independent power supply sections according to the up and down lines and the adjacency relationship with adjacent substations;

[0008] If the sum of the through-ground currents of the two power supply sections in a pair of adjacent unidirectional power supply sections between two adjacent substations is greater than zero, then it is confirmed that there is leakage in the power supply section range of the pair of adjacent unidirectional power supply sections.

[0009] The sum of the grounding currents of the two power supply sections in the adjacent pair of unidirectional power supply sections between the two adjacent substations is the leakage current of the adjacent pair of unidirectional power supply sections.

[0010] Furthermore, the four independent power supply sections include an up-direction down-direction section, a down-direction down-direction section, an up-direction up-direction section, and a down-direction up-direction section;

[0011] Each of the four independent power supply sections includes a corresponding positive feeder, a negative feeder, a positive contact rail section, a negative contact rail section, a through ground wire, and a current sensor for measuring the current of the through ground wire.

[0012] The down-direction down-segment of a substation is connected to the up-direction down-segment of the next adjacent substation, forming a down-power supply segment adjacency pair; the down-direction up-segment of a substation is connected to the up-direction up-segment of the next adjacent substation, forming an up-power supply segment adjacency pair.

[0013] The unidirectional power supply segment adjacency pair includes the downlink power supply segment adjacency pair and the uplink power supply segment adjacency pair.

[0014] Furthermore, it also includes:

[0015] Based on the confirmed leakage current in a unidirectional power supply section, the current in the four connected ground wires between the two adjacent substations is used to determine the specific location of the leakage fault. The specific location of the leakage fault is determined using the following equation:

[0016]

[0017] Where D(i) is the distance from the leakage fault point to substation (i), L is the distance between substation (i) and substation (i+1), and I GRS (i), I GRX (i) represent the down-direction up-section ground wire current and the down-direction down-section ground wire current of substation (i), respectively. GLS (i+1), I GLX (i+1) represents the up-direction up-segment ground wire current and the up-direction down-segment ground wire current of substation (i+1), respectively.

[0018] Furthermore, before determining that the sum of the through-ground currents of the two power supply sections in a pair of adjacent unidirectional power supply sections between two adjacent substations is greater than zero, the method further includes:

[0019] Establish the equivalent circuit for the downlink power supply segment adjacency pair and the uplink power supply segment adjacency pair between the two adjacent substations;

[0020] Obtain the through-ground current of each of the four power supply segments jointly included by the downlink power supply segment adjacency pair and the uplink power supply segment adjacency pair between the two adjacent substations.

[0021] Secondly, the present invention also provides a method for locating leakage faults in a maglev transportation traction power supply system, comprising: obtaining the specific location of the leakage fault point based on the current of four connected ground wires between two adjacent substations of a unidirectional power supply section where leakage has been confirmed.

[0022] The specific location of the leakage fault point is obtained through the following equation:

[0023]

[0024] Where D(i) is the distance from the leakage fault point to substation (i), L is the distance between substation (i) and substation (i+1), and I GRS (i), I GRX (i) represent the down-direction up-section ground wire current and the down-direction down-section ground wire current of substation (i), respectively. GLS (i+1), I GLX (i+1) represents the up-direction up-segment ground wire current and the up-direction down-segment ground wire current of substation (i+1), respectively.

[0025] Thirdly, the present invention also provides a leakage current protection method for a maglev transportation traction power supply system, comprising:

[0026] Each substation of the traction power supply system is divided into four independent power supply sections according to the up and down lines and the adjacency relationship with adjacent substations;

[0027] If the sum of the through-ground currents of the two power supply sections in a pair of adjacent unidirectional power supply sections between two adjacent substations is greater than zero, then it is confirmed that there is leakage in the power supply section range of the pair of adjacent unidirectional power supply sections.

[0028] The adjacent pairs in this unidirectional power supply section are protected by a step-by-step power outage.

[0029] Furthermore, the step-by-step power outage protection for adjacent pairs in the unidirectional power supply section specifically includes:

[0030] If the sum of the through-ground currents of the two adjacent power supply sections in the unidirectional power supply section between the two adjacent substations is greater than the first current value, and after a first time delay, it is still greater than the first current value, then an alarm signal is issued.

[0031] If the sum of the through-ground currents of the two power supply sections in the adjacent pair of the one-way power supply sections between the two adjacent substations is greater than the second current value, and after a second delay, it is still greater than the second current value, then the corresponding feeder switches of the two power supply sections in the adjacent pair of the one-way power supply sections are disconnected.

[0032] After a third time delay, if it is determined that the corresponding feeder switches of the two adjacent power supply sections in the one-way power supply section are still not disconnected, then the corresponding feeder switches of all power supply sections of the two adjacent substations are disconnected.

[0033] Wherein, the second current value is greater than the first current value, and the third time is greater than the second time.

[0034] Furthermore, the four independent power supply sections include an up-direction down-direction section, a down-direction down-direction section, an up-direction up-direction section, and a down-direction up-direction section;

[0035] Each of the four independent power supply sections includes a corresponding positive feeder, a negative feeder, a positive contact rail section, a negative contact rail section, a through ground wire, and a current sensor for measuring the current of the through ground wire.

[0036] The down-direction down-segment of a substation is connected to the up-direction down-segment of the next adjacent substation, forming a down-power supply segment adjacency pair; the down-direction up-segment of a substation is connected to the up-direction up-segment of the next adjacent substation, forming an up-power supply segment adjacency pair.

[0037] The unidirectional power supply segment adjacency pair includes the downlink power supply segment adjacency pair and the uplink power supply segment adjacency pair.

[0038] Furthermore, after performing step-by-step power outage protection on adjacent pairs of the unidirectional power supply section, the following is also included:

[0039] Based on the current of the four connected ground wires between the two adjacent substations in a unidirectional power supply section where leakage has been confirmed, the specific location of the leakage fault point is obtained.

[0040] Eliminate the leakage fault at its specific location and restore power supply.

[0041] Furthermore, the equation characterizing the current in the four connected ground wires between two adjacent substations of a unidirectional power supply section with confirmed leakage, to obtain the specific location of the leakage fault point, includes:

[0042]

[0043] Where D(i) is the distance from the leakage fault point to substation (i), L is the distance between substation (i) and substation (i+1), and I GRS (i), I GRX (i) represent the down-direction up-section ground wire current and the down-direction down-section ground wire current of substation (i), respectively. GLS (i+1), I GLX (i+1) represents the up-direction up-segment ground wire current and the up-direction down-segment ground wire current of substation (i+1), respectively.

[0044] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:

[0045] (1) The leakage fault location method of the present invention divides each substation of the medium and low speed maglev traction power supply system into four independent power supply sections according to the up and down lines and the adjacency relationship with adjacent substations. By judging whether the sum of the through ground current of the two power supply sections in a certain unidirectional power supply section adjacency pair between two adjacent substations (that is, the leakage current of the two power supply sections) is greater than zero, the specific unidirectional power supply section adjacency pair where the leakage fault point is located can be accurately located. This lays the technical foundation for subsequent targeted step-by-step power outage protection and further determination of the precise location of the leakage fault point.

[0046] (2) The leakage fault location method of the present invention first accurately locates the specific unidirectional power supply section adjacent to the leakage fault point. Based on the current of the four through ground wires between the two adjacent substations of the unidirectional power supply section adjacent to the confirmed leakage fault point, the specific and precise location of the leakage fault point can be calculated and determined. This fills the technical gap in the precise location of leakage fault points and provides a technical basis for subsequent targeted elimination of leakage faults and restoration of power supply.

[0047] (3) Based on the precise location of the leakage fault point in the specific unidirectional power supply section adjacent pair, the leakage protection method of the present invention can perform step-by-step power outage protection on the unidirectional power supply section adjacent pair, thereby avoiding the situation where multiple substations trip due to a DC ground fault in any line, minimizing the power outage range and reducing the interference to the power supply system.

[0048] (4) The leakage protection method of the present invention is based on the comparison and judgment of the leakage current of the adjacent pair of the unidirectional power supply section with a series of preset current thresholds, combined with the judgment of a series of delay thresholds, and constructs a technical measure system for step-by-step power outage protection of the adjacent pair of the unidirectional power supply section, thereby avoiding the situation that multiple substations will trip directly due to a DC grounding fault in any line, minimizing the scope of power outage and reducing the interference to the power supply system.

[0049] (5) Based on the precise location of the specific unidirectional power supply section adjacent to the leakage fault point, the leakage protection method of the present invention can calculate and determine the specific precise location of the leakage fault point based on the current of the four through ground wires between the two adjacent substations of the unidirectional power supply section adjacent to the confirmed leakage fault point. This can reduce the scope of subsequent leakage fault investigation, reduce maintenance workload, and improve the efficiency of leakage fault troubleshooting. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 A flowchart illustrating a method for locating leakage faults in a medium-low speed maglev traction power supply system, provided in an embodiment of the present invention.

[0052] Figure 2 A circuit diagram of any one of the substations in a medium-low speed maglev transportation traction power supply system provided for an embodiment of the present invention;

[0053] Figure 3 A circuit diagram of a medium-low speed maglev traction power supply system provided in an embodiment of the present invention;

[0054] Figure 4 A schematic diagram of the current distribution in the equivalent circuit of leakage fault provided in an embodiment of the present invention. Detailed Implementation

[0055] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0056] The terms "first," "second," or "third," etc., used in the specification, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a particular order. Furthermore, the terms "comprising" or "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0057] refer to Figure 1 In one embodiment, the entire technical means of a leakage current protection method for a medium- and low-speed maglev transportation traction power supply system may include the following steps, wherein the leakage current protection method includes a leakage fault location method. To avoid redundancy, the leakage fault location method and the leakage current protection method will be described together through an embodiment of the leakage current protection method below.

[0058] Step 1: Divide each substation of the traction power supply system into four independent power supply sections according to the up and down lines and the adjacency relationship with adjacent substations.

[0059] The four power supply sections include the left adjacent downlink section, the right adjacent downlink section, the left adjacent uplink section, and the right adjacent uplink section, such as... Figure 2 As shown. Each substation is equipped with a controller for receiving DC grounding protection trip signals from the DC grounding protection device 64D, communicating with adjacent substations, and controlling the tripping of feeder cabinets in the power supply section; a current sensor is installed on each through ground wire connected to the grounding busbar of the DC grounding protection device 64D.

[0060] Each power supply section includes a positive feeder, a negative feeder, a positive contact rail, a negative contact rail, a corresponding through ground wire, and its current sensor. The through ground wire of each power supply section is connected to the grounding busbar of the DC grounding protection device 64D. When multiple substations are operating, the right adjacent uplink section of substation (i) is connected to the left adjacent uplink section of substation (i+1), and the right adjacent downlink section of substation (i) is connected to the left adjacent downlink section of substation (i+1).

[0061] More specifically, such as Figure 2 As shown, the substation (i) includes feeder cabinets 211 and 2211, a grounding wire GLX, and a current sensor TA. LX The components include the left adjacent downlink section, feeder cabinets 212 and 2212, the through ground wire GLS, and the current sensor TA. LS The components include the left adjacent uplink section, feeder cabinets 213 and 2213, the through ground wire GRX, and the current sensor TA. RXThe right adjacent downlink section, feeder cabinets 214 and 2214, as well as the through ground wire GRS and current sensor TA are composed of RS The right-adjacent upward segment. For example... Figure 3 As shown, the right adjacent downlink segment of substation (i) is connected to the left adjacent downlink segment of substation (i+1), and the right adjacent uplink segment of substation (i) is connected to the left adjacent uplink segment of substation (i+1).

[0062] Step 2: If the sum of the through-ground currents of the two power supply sections in a pair of adjacent unidirectional power supply sections between two adjacent substations is greater than zero, then it is confirmed that there is leakage in the power supply section range of the pair of adjacent unidirectional power supply sections.

[0063] First, establish the equivalent circuit of the power supply section between two adjacent substations, and label the resistance and current in each circuit. Figure 4 The example shows the resistance of each contact rail section and the ground wire, R. C R is the resistance of the train load. j I is the transition resistance at the leakage fault point. j This refers to the leakage fault current (i.e., leakage current).

[0064] The system detects the current in the grounding wires of the four power supply sections of each substation: the grounding wire current in the left adjacent downlink section, the grounding wire current in the left adjacent uplink section, the grounding wire current in the right adjacent downlink section, and the grounding wire current in the right adjacent uplink section; as well as the current flowing through the 64D device; and connects to the network to read the grounding wire current values ​​of adjacent substations. The positive direction of the current is defined as the grounding wire pointing towards the 64D grounding busbar of the DC grounding protection device.

[0065] Analyze the equivalent circuit of the power supply section and calculate the leakage current of the upstream power supply section and the downstream power supply section between two adjacent substations.

[0066] I LSF (i+1)=I RSF (i)=I GRS (i)+I GLS (i+1)

[0067] I LXF (i+1)=I RXF (i)=I GRX (i)+I GLX (i+1)

[0068] Among them, I LSF (i+1), I LXF (i+1) represent the leakage current of the left adjacent uplink segment and the left adjacent downlink segment of the substation (i+1), respectively. RSF (i), I RXF(i) represents the leakage current of the right adjacent uplink section and the right adjacent downlink section of substation (i), respectively. GRS (i), I GRX (i) represent the grounding current of the right adjacent uplink section and the grounding current of the right adjacent downlink section of substation (i), respectively. GLS (i+1), I GLX (i+1) represents the grounding current of the left adjacent uplink section and the grounding current of the left adjacent downlink section of substation (i+1), respectively.

[0069] When a leakage fault occurs between substation (i) and substation (i+1), the leakage current I RSF (i) or I RXF (i) A value greater than zero may occur, or I LSF (i+1) or I LXF (i+1) can have a value greater than zero.

[0070] A unidirectional power supply section adjacency pair refers to two connected power supply sections, both located in the upward section and / or both located in the downward section, between two adjacent substations. Because the direction of travel in maglev rail transit is opposite to that in automobiles, it travels on the left. Therefore, see [reference needed]. Figure 3 ,exist Figure 3 In the lower upward section, the train travels on the positive and negative upward contact tracks. Figure 3 Driving on the left in the middle; while Figure 3 In the lower section, the train travels on the positive and negative contact tracks. Figure 3 The vehicle travels on the right side of the road. Therefore, the upward direction downward section, the downward direction downward section, the upward direction upward section, and the downward direction upward section in the claims can respectively correspond to the left adjacent downward section, the right adjacent downward section, the left adjacent upward section, and the right adjacent upward section in this embodiment.

[0071] When a leakage fault occurs in the right-adjacent up-line section of substation (i), the equivalent circuit current distribution of the right-adjacent up-line and down-line sections of substation (i) and the left-adjacent up-line and down-line sections of the adjacent substation (i+1) is as follows: Figure 4 As shown.

[0072] According to Kirchhoff's Current Law, the current relationship at the point where a leakage fault occurs in the right adjacent upstream section of substation (i) is as follows:

[0073] I LSF (i+1)=I RSF (i)=I GRS (i)+I GLS (i+1)=I J

[0074] Since no leakage occurred in the downstream section to the right of substation (i), the current relationship is as follows:

[0075] I LXF (i+1)=I RXF (i)=I GRX (i)+I GLX (i+1)=0

[0076] By detecting the grounding current of each connected wire in this substation and reading the grounding current of each connected wire in adjacent substations via network connection, the leakage current of the four power supply sections of this substation can be monitored in real time. By determining whether the sum of the grounding currents of the two connected wires in a pair of adjacent unidirectional power supply sections between two adjacent substations is greater than zero, the specific pair of adjacent unidirectional power supply sections where the leakage fault point is located can be accurately located. This lays the technical foundation for subsequent targeted step-by-step power outage protection and further determination of the precise location of the leakage fault point.

[0077] Step 3: Implement step-by-step power disconnection protection for adjacent pairs of the unidirectional power supply section with leakage.

[0078] Specifically, in substation (i), the leakage current I... RSF (i) or I RXF (i) Compare with the set value. When the leakage current I RSF (i) or I RXF (i) Greater than the set value I SET1 At that time, after a delay of T SET1 Such as leakage current I RSF (i) or I RXF (i) is still greater than the set value I SET1 If the leakage current is low, an alarm will sound. This is the alarm stage when the leakage current is relatively small, so as to draw necessary attention.

[0079] When leakage current I RSF (i) or I RXF (i) Greater than the set value I SET2 (I SET2 >I SET1 When, after a delay T SET2 Such as leakage current I RSF (i) or I RXF (i) is still greater than the set value I SET2 If the leakage current increases further, only the feeder switch of the leakage section will be disconnected, while the feeder switches of adjacent substations will also be disconnected. This is the partial power outage stage when the leakage current is large.

[0080] As via T SET3 (T SET3 >T SET2If no action is taken within the specified time (T), the DC grounding protection device 64D will directly disconnect the corresponding feeder cabinet switch. That is, after a third time delay (T...),... SET3 If it is determined that the corresponding feeder switches of the two adjacent power supply sections in the unidirectional power supply section are still not disconnected, the DC grounding protection device 64D will directly disconnect the corresponding feeder switches of all power supply sections of the two adjacent substations.

[0081] In the above-mentioned tiered power outage protection, when the leakage current reaches a certain current threshold, an alarm signal is issued first to attract necessary attention. If the leakage current continues to increase, only the leakage section is cut off. If the aforementioned cutting-off measures fail to take effect, then the entire power supply section of the adjacent substation is cut off. This avoids the situation where multiple substations trip due to a DC ground fault on any line, minimizing the scope of the power outage and reducing the interference to the power supply system.

[0082] The current setting value and time setting value can be determined according to the specific situation of the traction power supply system for medium and low speed maglev transportation.

[0083] Step 4: Based on the current of the four connected ground wires between the two adjacent substations of the confirmed unidirectional power supply section with leakage, obtain the specific location of the leakage fault point.

[0084] Furthermore, if a leakage fault occurs in the power supply section between substation (i) and substation (i+1), the distance from the leakage fault point to substation (i) can be calculated based on the equivalent circuit:

[0085]

[0086] Where D(i) is the distance from the leakage fault point to substation (i), L is the distance between substation (i) and substation (i+1), and I GRS (i), I GRX (i) represent the through ground current of the right adjacent uplink section and the through ground current of the right adjacent downlink section of substation (i), respectively. GLS (i+1), I GLX (i+1) represents the grounding current of the left adjacent uplink section and the grounding current of the left adjacent downlink section of substation (i+1), respectively.

[0087] Based on the distance results obtained from the above calculations, the precise location of the leakage fault point can be obtained, thus filling the technical gap in the precise location of leakage fault points and providing a technical basis for subsequent targeted elimination of leakage faults and restoration of power supply.

[0088] Step 5: Accurately locate the leakage fault at its precise position and restore power. This will narrow down the scope of subsequent leakage fault investigation, reduce maintenance workload, and improve the efficiency of leakage fault troubleshooting.

[0089] Those skilled in the art will understand that the features described in the various embodiments and / or claims of this disclosure can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in this disclosure. In particular, the features described in the various embodiments and / or claims of this disclosure can be combined and / or combined in various ways without departing from the spirit and teachings of this disclosure, and all such combinations and / or combinations fall within the scope of this disclosure.

[0090] Although this disclosure has been shown and described with reference to specific exemplary embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made to this disclosure without departing from the spirit and scope of the disclosure as defined by the appended claims and their equivalents. Therefore, the scope of this disclosure should not be limited to the above embodiments, but should be defined not only by the appended claims, but also by their equivalents.

Claims

1. A method for locating leakage faults in a maglev transportation traction power supply system, characterized in that, include: Each substation of the traction power supply system is divided into four independent power supply sections according to the up and down lines and the adjacency relationship with adjacent substations; If the sum of the through-ground currents of the two power supply sections in a pair of adjacent unidirectional power supply sections between two adjacent substations is greater than zero, then it is confirmed that there is leakage in the power supply section range of the pair of adjacent unidirectional power supply sections. Among them, the sum of the through ground currents of the two power supply sections in the adjacent pair of unidirectional power supply sections between the two adjacent substations is the leakage current of the adjacent pair of unidirectional power supply sections. The four independent power supply sections include an up-direction down-direction section, a down-direction down-direction section, an up-direction up-direction section, and a down-direction up-direction section; Each of the four independent power supply sections includes a corresponding positive feeder, a negative feeder, a positive contact rail section, a negative contact rail section, a through ground wire, and a current sensor for measuring the current of the through ground wire. The down-direction down-segment of a substation is connected to the up-direction down-segment of the next adjacent substation, forming a down-power supply segment adjacency pair; the down-direction up-segment of a substation is connected to the up-direction up-segment of the next adjacent substation, forming an up-power supply segment adjacency pair. The unidirectional power supply segment adjacency pair includes the downlink power supply segment adjacency pair and the uplink power supply segment adjacency pair; Before determining that the sum of the through-ground currents of the two adjacent power supply sections in a unidirectional power supply section between two adjacent substations is greater than zero, the following steps are also included: Establish the equivalent circuit for the downlink power supply segment adjacency pair and the uplink power supply segment adjacency pair between the two adjacent substations; Obtain the through-ground current of each of the four power supply segments jointly included by the downlink power supply segment adjacency pair and the uplink power supply segment adjacency pair between the two adjacent substations.

2. The leakage fault location method as described in claim 1, characterized in that, Also includes: Based on the confirmed leakage current in a unidirectional power supply section, the current in the four connected ground wires between the two adjacent substations is used to determine the specific location of the leakage fault. The specific location of the leakage fault is determined using the following equation: Where D(i) is the distance from the leakage fault point to substation (i), L is the distance between substation (i) and substation (i+1), and I GRS (i), I GRX (i) represent the down-direction up-section ground wire current and the down-direction down-section ground wire current of substation (i), respectively. GLS (i+1), I GLX (i+1) represents the up-direction up-segment ground wire current and the up-direction down-segment ground wire current of substation (i+1), respectively.

3. A method for locating leakage faults in a maglev transportation traction power supply system, characterized in that, include: Based on the current of the four connected ground wires between the two adjacent substations in a unidirectional power supply section where leakage has been confirmed, the specific location of the leakage fault point is obtained. The specific location of the leakage fault point is obtained through the following equation: Where D(i) is the distance from the leakage fault point to substation (i), L is the distance between substation (i) and substation (i+1), and I GRS (i), I GRX (i) represent the down-direction up-section ground wire current and the down-direction down-section ground wire current of substation (i), respectively. GLS (i+1), I GLX (i+1) represents the up-direction up-segment ground wire current and the up-direction down-segment ground wire current of substation (i+1), respectively.

4. A leakage current protection method for a maglev transportation traction power supply system, characterized in that, include: Each substation of the traction power supply system is divided into four independent power supply sections according to the up and down lines and the adjacency relationship with adjacent substations; If the sum of the through-ground currents of the two power supply sections in a pair of adjacent unidirectional power supply sections between two adjacent substations is greater than zero, then it is confirmed that there is leakage in the power supply section range of the pair of adjacent unidirectional power supply sections. Implement step-by-step power outage protection for adjacent pairs in this unidirectional power supply section; The four independent power supply sections include an up-direction down-direction section, a down-direction down-direction section, an up-direction up-direction section, and a down-direction up-direction section; Each of the four independent power supply sections includes a corresponding positive feeder, a negative feeder, a positive contact rail section, a negative contact rail section, a through ground wire, and a current sensor for measuring the current of the through ground wire. The down-direction down-segment of a substation is connected to the up-direction down-segment of the next adjacent substation, forming a down-power supply segment adjacency pair; the down-direction up-segment of a substation is connected to the up-direction up-segment of the next adjacent substation, forming an up-power supply segment adjacency pair. The unidirectional power supply segment adjacency pair includes the downlink power supply segment adjacency pair and the uplink power supply segment adjacency pair; Before determining that the sum of the through-ground currents of the two adjacent power supply sections in a unidirectional power supply section between two adjacent substations is greater than zero, the following steps are also included: Establish the equivalent circuit for the downlink power supply segment adjacency pair and the uplink power supply segment adjacency pair between the two adjacent substations; Obtain the through-ground current of each of the four power supply segments jointly included by the downlink power supply segment adjacency pair and the uplink power supply segment adjacency pair between the two adjacent substations.

5. The leakage current protection method as described in claim 4, characterized in that, The step-by-step power outage protection for adjacent pairs in the unidirectional power supply section specifically includes: If the sum of the through-ground currents of the two adjacent power supply sections in the unidirectional power supply section between the two adjacent substations is greater than the first current value, and after a first time delay, it is still greater than the first current value, then an alarm signal is issued. If the sum of the through-ground currents of the two power supply sections in the adjacent pair of the one-way power supply sections between the two adjacent substations is greater than the second current value, and after a second delay, it is still greater than the second current value, then the corresponding feeder switches of the two power supply sections in the adjacent pair of the one-way power supply sections are disconnected. After a third time delay, if it is determined that the corresponding feeder switches of the two adjacent power supply sections in the one-way power supply section are still not disconnected, then the corresponding feeder switches of all power supply sections of the two adjacent substations are disconnected. Wherein, the second current value is greater than the first current value, and the third time is greater than the second time.

6. The leakage current protection method as described in claim 4, characterized in that, The step-by-step power outage protection for adjacent pairs in the unidirectional power supply section also includes: Based on the current of the four connected ground wires between the two adjacent substations in a unidirectional power supply section where leakage has been confirmed, the specific location of the leakage fault point is obtained. Eliminate the leakage fault at its specific location and restore power supply.

7. The leakage current protection method as described in claim 6, characterized in that, The equation characterizing the current in the four connected ground wires between two adjacent substations in a unidirectional power supply section where leakage has been confirmed, and which determines the specific location of the leakage fault, includes: Where D(i) is the distance from the leakage fault point to substation (i), L is the distance between substation (i) and substation (i+1), and I GRS (i), I GRX (i) represent the down-direction up-section ground wire current and the down-direction down-section ground wire current of substation (i), respectively. GLS (i+1), I GLX (i+1) represents the up-direction up-segment ground wire current and the up-direction down-segment ground wire current of substation (i+1), respectively.

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