Traction network out-of-phase short circuit relay protection method based on adjacent line current increment

Abstract

The method for traction network out-of-phase short-circuit relay protection based on adjacent line current increment includes: collecting the currents of the first and second traction network lines, and calculating the current increments of the first and second traction network lines by subtracting the current effective value before one power frequency cycle from the current effective value at the current moment; the first and second traction network lines are adjacent; if the first traction network line meets the starting condition, entering the delay stage, and sending the current increment starting signal to the second traction network line; if the current increment of the first traction network line is greater than the current increment setting value in the delay stage, tripping all line circuit breakers of the first traction network line when the first traction network line receives the current increment starting signal sent by the second traction network line; and completing the protection of the second traction network line according to the protection logic of the first traction network line. The protection of the present application does not need synchronization, and only the traction network line with out-of-phase short-circuit fault is removed, and the others are not affected.

Description

Technical Field

[0001] This invention relates to the field of electrified railway power supply technology, and in particular to a method for traction network phase-to-phase short-circuit relay protection based on the current increment of adjacent lines. Background Technology

[0002] my country's electrified railways employ a cyclic phase-switching, segmented power supply method, drawing power from the three-phase power grid alternately to supply power to the power supply arms. Electrical phase separation is installed between two power supply arms with different phases to strictly insulate against voltage differences. When an electric locomotive, while energized, enters an electrical phase separation, the two power supply arms with different phases become connected, resulting in a phase-to-phase short circuit fault. Current traction network distance protection and current increment protection are insufficient for complete protection against phase-to-phase short circuit faults, and protection failures occur frequently, leading to serious consequences and posing a significant threat to the safe and stable operation of the traction power supply system.

[0003] Patent CN200810053159, "Protection Method for Out-of-Phase Short Circuits in Traction Power Supply Systems," and the literature "Research on the Principle of Novel Out-of-Phase Short Circuit Protection in Traction Power Supply" (Power System Protection and Control, Vol. 38, No. 22, 2010, pp. 63-67) propose out-of-phase short circuit protection methods based on inter-phase voltage harmonics. This method is designed for the voltage characteristics of electric arcs and cannot protect against out-of-phase short circuit faults not caused by electric arcs.

[0004] Patent CN201010557242, "Automatic Tripping Method for Electrified Railway Feeders Started by External Contacts," proposes a method for determining whether a short circuit has occurred in an electrical phase using the backup protection device of the traction transformer. This method requires external activation via the traction transformer protection, increasing its complexity.

[0005] Patents CN2020109927530 "A Relay Protection Method for Traction Network Power Supply Arm Based on Directional Current Element", CN2020110049560 "A Relay Protection Method for Traction Network Power Supply Arm Based on Directional Incremental Current Element", and CN2020110049433 "A Relay Protection Method for Traction Network Power Supply Arm Based on Directional Impedance Element" propose protection methods for power supply arms. These methods target line-to-ground faults and line-to-line faults within the power supply arm, but cannot reliably protect against out-of-phase short-circuit faults occurring between two power supply arms.

[0006] The paper "Anisotropic Short Circuit Protection of Power Supply Traction Network Based on Fault Component Correlation Analysis" (Automation of Electric Power Systems, 2007, Vol. 31, No. 6, pp. 82-85) proposes an anisotropic short circuit protection method that extracts fault characteristics using correlation analysis. This method places high demands on the synchronization of current measurements, which is not conducive to engineering implementation.

[0007] The literature "Analysis of Out-of-Phase Short Circuit Faults Based on Contact Line Temperature" (Journal of Dalian Jiaotong University, Vol. 31, No. 4, 2010, pp. 38-40, 62) proposes an out-of-phase short circuit protection method based on contact line temperature. This method requires waiting for the accumulation of the thermal effect of the short-circuit current, resulting in a relatively long operating time, which is not conducive to rapid protection operation.

[0008] The paper "Backup Distance Protection for Traction Transformers in High-Speed ​​Railways" (Electrical Automation Equipment, Vol. 32, No. 6, 2012, pp. 27-32) proposes a method for protecting against out-of-phase short circuits by configuring distance protection on the low-voltage side of the traction transformer. This method's trip signal acts on the circuit breaker on the low-voltage side of the traction transformer, which can expand the power outage range after an out-of-phase short circuit and reduce the reliability of power supply. Summary of the Invention

[0009] The purpose of this invention is to provide a relay protection method for traction network out-of-phase short circuits based on the current increment of adjacent lines, which can quickly identify and isolate faults after a fault occurs, especially for the identification and protection of out-of-phase short circuit faults in traction networks.

[0010] The technical solution for achieving the objective of this invention is as follows:

[0011] Traction network interphase short-circuit relay protection methods based on the current increment of adjacent lines include:

[0012] The current of the first traction network line is collected, the effective value of the current is calculated, and the difference between the effective value of the current at the current moment and the effective value of the current one power frequency cycle ago is calculated to obtain the current increment of the first traction network line; the second traction network line is adjacent to the first traction network line, and the current increment of the second traction network line is obtained in the same way as the current increment of the first traction network line.

[0013] If the first traction network line meets the starting conditions, it enters the delay stage and sends a current increment start signal to the second traction network line; if the current increment of the first traction network line is greater than its current increment setting value during the delay stage, then when the first traction network line receives the current increment start signal sent by the second traction network line, all line circuit breakers of the first traction network line will trip.

[0014] If the second traction network line meets the starting conditions, it enters the delay stage and sends a current increment start signal to the first traction network line; if the current increment of the second traction network line is greater than its current increment setting value during the delay stage, then when the second traction network line receives the current increment start signal sent by the first traction network line, all line circuit breakers of the second traction network line will trip.

[0015] The specific start-up condition is: the current increment of the traction network line is greater than its current increment setting value;

[0016] During the delay phase, the current increment of the traction network line is calculated by subtracting the effective current value of the traction network line at the current moment from the effective current value one power frequency cycle before the start of the delay phase.

[0017] Furthermore, the second traction network line is adjacent to the first traction network line, specifically: the first traction network line is connected to the α-phase bus of the traction substation, and the second traction network line is connected to the β-phase bus of the traction substation; or, the first traction network line is connected to the β-phase bus of the traction substation, and the second traction network line is connected to the α-phase bus of the traction substation.

[0018] Furthermore, the second traction network line is adjacent to the first traction network line, specifically: the first traction network line is connected to the busbar of the traction substation, and the second traction network line is connected to the busbar of the traction substation adjacent to the said traction substation.

[0019] Furthermore, the starting condition is replaced by: the current increment of the traction network line is greater than its current increment setting value, and the ratio of the effective value of the second harmonic of the current to the effective value of the fundamental current is less than the second harmonic blocking setting value.

[0020] Furthermore, the traction network line includes a T-line, and the current of the traction network line is the T-line current.

[0021] Furthermore, the traction network line also includes an F-line, and the current of the traction network line is a combination of the T-line current and the F-line current.

[0022] In the above technical solution, the current of the first traction network line is collected by: collecting the feeder current at the substation of the first traction network line, or collecting the feeder current at the AT of the first traction network line, or collecting the feeder current at the section of the first traction network line, or collecting the feeder current at the switch of the first traction network line; the current of the second traction network line is collected by: collecting the feeder current at the substation of the second traction network line, or collecting the feeder current at the AT of the second traction network line, or collecting the feeder current at the section of the second traction network line, or collecting the feeder current at the switch of the second traction network line.

[0023] The beneficial effects of this invention are as follows:

[0024] (1) Configure traction network out-of-phase short circuit relay protection based on the current increment of adjacent lines in the traction network line. Utilize the fault characteristic that the current of two adjacent lines suddenly increases when an out-of-phase short circuit occurs in the traction network. When the current increment of this line is started and the current increment start signal of the adjacent line is received within a certain delay, the out-of-phase short circuit protection is started, so as to quickly and accurately identify the traction network line that has an out-of-phase short circuit fault.

[0025] (2) It is simple to implement. The protection devices do not need to be synchronized. Only the traction network line that has an out-of-phase short circuit fault is disconnected, while other traction networks and traction transformers are not affected.

[0026] (3) It can be used for both phase short circuits caused by fault arcs and phase short circuits caused by suspension wires or foreign objects; it can protect both phase short circuit faults in substations and phase short circuit faults in zones. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of an out-of-phase short circuit fault.

[0028] Figure 2 This is the action logic diagram for Protection 1.

[0029] Figure 3 This is the action logic diagram for Protection 2.

[0030] Figure 4 This is the protection action logic diagram.

[0031] Figure 5 This is the protection 4-action logic diagram.

[0032] Figure 6 This is a schematic diagram of the phase-to-phase short-circuit protection at the substation of a fully parallel AT power supply system with dual circuit breakers.

[0033] Figure 7 This is a schematic diagram of the phase-to-phase short-circuit protection at the substation of a fully parallel AT power supply system in single-circuit-breaker mode.

[0034] Figure 8 This is a schematic diagram of the phase-to-phase short-circuit protection at the substation of the dual-line direct power supply system.

[0035] Figure 9 This is a schematic diagram of the phase-to-phase short-circuit protection at a substation in a single-line direct power supply system.

[0036] Figure 10 This is a schematic diagram of the phase-short circuit protection for the partition.

[0037] Figure 11 This is a logic diagram for adding a second harmonic blocking criterion. Detailed Implementation

[0038] The invention will be further described below with reference to the accompanying drawings.

[0039] The traction substation draws power from the three-phase power grid and feeds it to two busbars of different phases, called the α-phase busbar and the β-phase busbar. The traction network feeders are connected to the busbars and are divided into uplink and downlink lines, etc. Figure 1As shown (the traction network feeders for both the uplink and downlink lines can be one or more; the diagram shows one feeder as an example). In the diagram, 1QF to 12QF are the feeder circuit breakers installed in the traction substation, AT substation 1, AT substation 2, section substation 1, and section substation 2, respectively, and they are controlled by the corresponding protections 1 to 12.

[0040] The method for interphase short-circuit relay protection of traction network based on the current increment of adjacent lines is as follows:

[0041] Current increment criteria are set for the α-phase up and down lines, and the β-phase up and down lines. When a phase-to-phase short circuit fault occurs in the traction network, taking the phase-to-phase short circuit fault between the α-phase up line and the β-phase up line as an example, the α-phase and β-phase are suddenly connected due to the phase-to-phase short circuit. The fault current mainly flows through the 1QF-fault point-3QF loop, and the measured current at 1QF and 3QF is... and The effective values ​​I1 and I3 both increase significantly at the same time, and the current increment criterion for protection 1 is that ΔI1 is greater than the setting value ΔI set1 However, upon startup, the current increment criterion at protection point 3 is greater than the setting value ΔI. set3 Therefore, within a certain period of time, the current increment criterion at protection 1 will be activated and will receive the current increment criterion activation signal at protection 3, thus accurately identifying that an out-of-phase short circuit fault has occurred at protection 1QF; similarly, the current increment criterion at protection 3 will be activated and will receive the current increment criterion activation signal at protection 1, thus accurately identifying that an out-of-phase short circuit fault has occurred at protection 3QF.

[0042] Due to the special parallel structure of the traction network, when such... Figure 1 As shown, in the case of an upward out-of-phase short-circuit fault, tripping only 1QF and 3QF is insufficient to clear the fault, because a fault loop can still be formed via 2QF-6QF-5QF-9QF-10QF-4QF. Therefore, when a protection device detects an out-of-phase short-circuit fault, all circuit breakers on the protected line should be tripped. That is, if protection 1 detects an out-of-phase short-circuit fault, it should trip all circuit breakers on that line, including 1QF, 5QF, and 7QF; similarly, if protection 3 detects an out-of-phase short-circuit fault, it should trip all circuit breakers on that line, including 3QF, 9QF, and 11QF.

[0043] In the traction network interphase short-circuit relay protection method based on the current increment of adjacent lines, the current increment is:

[0044] ΔI=I h -I q

[0045] In the formula, I h I is the effective value of the current at the current moment. q The effective value of the current one power frequency cycle ago

[0046] The activation condition for protecting i (i = 1, 2, 3, or 4) is:

[0047] ΔI i >I seti

[0048] In the formula, I seti The current setting value for protection i is set to avoid the maximum current increment of the protected line during normal operation.

[0049] After protection is enabled, the I at startup will be... q Recorded as The effective value of the current (i.e., the current one power frequency cycle prior to startup) is stored in the protection device. During the delay phase, the current increment is:

[0050]

[0051] Within a delay t, if the current increment criterion activation condition of this line is met and a current increment criterion activation signal from an adjacent line is received, then all feeder circuit breakers of this line will trip and a signal will be issued. The operating logic of protections 1 to 4 is as follows: Figures 2-5 As shown.

[0052] The specific implementation method is as follows:

[0053] 1. Example of phase-to-phase short-circuit protection in a fully parallel AT power supply system with dual circuit breakers

[0054] For example Figure 6 The protection implementation scheme for the parallel AT power supply system with dual circuit breakers shown is as follows:

[0055] Traction network phase-to-phase short-circuit protection based on the current increment of adjacent lines is configured for protection 1 to 4 corresponding to circuit breakers 1QF to 4QF, and the T-line current of each line is collected respectively. When the current increment exceeds the set value, the current increment criterion is activated. If the activation condition is met within the delay and a current increment criterion activation signal from an adjacent line is received, all circuit breakers on the corresponding line will trip. Specifically: if the current increment criterion of protection 1 is activated and a current increment criterion activation signal from protection 3 is received within the delay, then 1QF, 5QF, and 7QF will trip; if the current increment criterion of protection 2 is activated and a current increment criterion activation signal from protection 4 is received within the delay, then 2QF, 6QF, and 8QF will trip; if the current increment criterion of protection 3 is activated and a current increment criterion activation signal from protection 1 is received within the delay, then 3QF, 9QF, and 11QF will trip; if the current increment criterion of protection 4 is activated and a current increment criterion activation signal from protection 2 is received within the delay, then 4QF, 10QF, and 12QF will trip.

[0056] In the above scheme, the T-line current and F-line current can also be collected and combined as the feeder current. T-line current and F-line current The combined feeder current is Its effective value

[0057] 2. Example of phase-to-phase short-circuit protection in a fully parallel AT power supply system with single circuit breaker mode.

[0058] For example Figure 7 The protection implementation scheme for the single-circuit-breaker mode fully parallel AT power supply system shown is as follows:

[0059] Traction network phase-to-phase short-circuit protection based on the current increment of adjacent lines is configured for protections 1 to 4 corresponding to circuit breakers 1QF to 4QF, and the T-line current of each line is collected respectively. When the current increment is greater than the setting value, the current increment criterion is activated. If the activation condition is met within the delay and the current increment criterion activation signal of the adjacent line is received, all circuit breakers of the corresponding line are tripped. That is: if the current increment criterion of protection 1 is activated and the current increment criterion activation signal of protection 3 is received within the delay, then 1QF, 5QF and 6QF are tripped; if the current increment criterion of protection 2 is activated and the current increment criterion activation signal of protection 4 is received within the delay, then 2QF, 5QF and 6QF are tripped; if the current increment criterion of protection 3 is activated and the current increment criterion activation signal of protection 1 is received within the delay, then 3QF, 7QF and 8QF are tripped; if the current increment criterion of protection 4 is activated and the current increment criterion activation signal of protection 2 is received within the delay, then 4QF, 7QF and 8QF are tripped.

[0060] Similarly, the T-line current and F-line current can be collected and combined to form the feeder current.

[0061] 3. Example of phase-short circuit protection at substations in dual-line direct power supply systems

[0062] For example Figure 8 The protection implementation scheme for the substation's phase-to-phase short circuit in the dual-line direct power supply system shown is as follows:

[0063] Traction network phase-to-phase short-circuit protection based on the current increment of adjacent lines is configured for protections 1 to 4 corresponding to circuit breakers 1QF to 4QF, and feeder current (T-line current) is collected respectively. When the current increment is greater than the setting value, the current increment criterion is activated. If the activation condition is met within the delay and the current increment criterion activation signal of the adjacent line is received, all circuit breakers of the corresponding line are tripped. That is: if the current increment criterion of protection 1 is activated and the current increment criterion activation signal of protection 3 is received within the delay, then 1QF and 5QF are tripped; if the current increment criterion of protection 2 is activated and the current increment criterion activation signal of protection 4 is received within the delay, then 2QF and 5QF are tripped; if the current increment criterion of protection 3 is activated and the current increment criterion activation signal of protection 1 is received within the delay, then 3QF and 6QF are tripped; if the current increment criterion of protection 4 is activated and the current increment criterion activation signal of protection 2 is received within the delay, then 4QF and 6QF are tripped.

[0064] 4. Example of phase-to-phase short-circuit protection in a single-line direct power supply system substation

[0065] For example Figure 9 The protection implementation scheme for the single-line direct power supply system shown is as follows:

[0066] Traction network phase-to-phase short-circuit protection based on the current increment of adjacent lines is configured for protections 1 to 2 corresponding to circuit breakers 1QF to 2QF, and feeder current (T-line current) is collected respectively. When the current increment is greater than the setting value, the current increment criterion is activated. If the activation condition is met within the delay and the current increment criterion activation signal of the adjacent line is received, all circuit breakers of the corresponding line are tripped. That is: if the current increment criterion of protection 1 is activated and the current increment criterion activation signal of protection 2 is received within the delay, then 1QF is tripped; if the current increment criterion of protection 2 is activated and the current increment criterion activation signal of protection 1 is received within the delay, then 2QF is tripped.

[0067] 5. Implementation Example of Different Phase Short Circuit Protection in Zoned Areas

[0068] The present invention discloses a traction network out-of-phase short-circuit protection method based on the current increment of adjacent lines. This method can achieve protection against out-of-phase short-circuit faults at the substation by leveraging the current increment characteristics of two adjacent lines at the substation location, and can also achieve protection against out-of-phase short-circuit faults in a zone by leveraging the current increment characteristics of adjacent lines between two substations. For example... Figure 10 For example, the protection implementation scheme for interphase short circuits in a fully parallel AT power supply system with dual circuit breaker mode is as follows. The protection implementation schemes for interphase short circuits in other types of power supply system zones are similar:

[0069] Traction network phase-to-phase short-circuit protection based on the current increment of adjacent lines is configured for protections 1 to 4 corresponding to circuit breakers 1QF to 4QF, and the T-line current is collected respectively. When the current increment is greater than the setting value, the protection is activated. If the activation condition is met within the delay and the current increment criterion activation signal of the adjacent line is received, all circuit breakers of the corresponding line are tripped. That is: if the current increment criterion of protection 1 is activated and the current increment criterion activation signal of protection 3 is received within the delay, then 1QF, 5QF and 7QF are tripped; if the current increment criterion of protection 2 is activated and the current increment criterion activation signal of protection 4 is received within the delay, then 2QF, 6QF and 8QF are tripped; if the current increment criterion of protection 3 is activated and the current increment criterion activation signal of protection 1 is received within the delay, then 3QF, 9QF and 11QF are tripped; if the current increment criterion of protection 4 is activated and the current increment criterion activation signal of protection 2 is received within the delay, then 4QF, 10QF and 12QF are tripped.

[0070] 6. Implementation example of adding second harmonic blocking criterion to current increment criterion

[0071] To prevent maloperation of the phase-short circuit protection due to inrush current caused by simultaneous overvoltage of trains on adjacent lines, a second harmonic blocking criterion can be added at each current increment criterion. When the current increment ΔI > I... set And the effective value of the second harmonic of the current at the current moment is I h2 The effective value of the fundamental current I at the current moment h1 The ratio is less than the set value K set The current increment criterion is activated, and the current increment criterion with added second harmonic blocking criterion is as follows: Figure 11 As shown.

[0072] After adding the second harmonic blocking criterion to the current increment criterion, the operation logic between the current increment criters of adjacent lines remains unchanged, and the method of protection against out-of-phase short circuits is still: within the delay t, if the current increment criterion activation condition of this line is met and the current increment criterion activation signal of the adjacent line is received, then all feeder circuit breakers of this line will be tripped and a signal will be issued.

[0073] After adding a second harmonic blocking criterion to the current increment criterion, the scope of application of the out-of-phase short circuit protection method disclosed in this invention remains unchanged. It can be used for out-of-phase short circuit protection in various power supply system substations, as well as for out-of-phase short circuit protection in zoned areas.

[0074] 7. Implementation Example When the Substation Circuit Breaker is Open

[0075] Due to maintenance of substation feeder circuit breakers or special operating conditions such as power supply detours, substation feeder circuit breakers may trip. To address out-of-phase short-circuit faults occurring when substation circuit breakers are open, current increment criteria can be configured on all feeders of the traction network line. This identifies out-of-phase short-circuit faults by detecting the activation of the current increment criteria on any feeder of the current line and any feeder of an adjacent line. Specifically, within a delay t, if the activation condition of the current increment criteria for any feeder of the current line is met and a current increment criteria activation signal is received from any feeder of an adjacent line, then all feeder circuit breakers of the current line will trip and a signal will be issued. For example... Figure 6 Taking the example of a phase-to-phase short circuit in a fully parallel AT power supply system with dual circuit breakers, the protection implementation scheme is as follows. The protection implementation schemes for phase-to-phase short circuits in other types of power supply systems and substations are similar:

[0076] Traction network phase-to-phase short-circuit protection based on the current increment of adjacent lines is configured for protections 1 to 12 corresponding to circuit breakers 1QF to 12QF, and the T-line current of each line is collected respectively. When the current increment of any protection exceeds the setting value, the current increment criterion of that protection is activated. If the activation condition is met within the delay and a current increment criterion activation signal is received from any feeder of the adjacent line, then all circuit breakers of the corresponding line are tripped. That is: if the current increment criterion of protection 1, protection 5, or protection 7 is activated and a current increment criterion activation signal is received from protection 3, protection 9, or protection 11 within the delay, then 1QF, 5QF, and 7QF are tripped; if the current increment criterion of protection 2, protection 6, or protection 8 .... If the current increment criterion start signal of protection 4, 10, or 12 is received, then 2QF, 6QF, and 8QF will trip; if the current increment criterion of protection 3, 9, or 11 is initiated and the current increment criterion start signal of protection 1, 5, or 7 is received within the delay, then 3QF, 9QF, and 11QF will trip; if the current increment criterion of protection 4, 10, or 12 is initiated and the current increment criterion start signal of protection 2, 6, or 8 is received within the delay, then 4QF, 10QF, and 12QF will trip.

[0077] Similarly, the T-line current and F-line current can be collected and combined to form the feeder current.

Claims

1. A traction network out-of-phase short circuit protection method based on the current increment of adjacent lines, characterized in that, include: The current of the first traction network line is collected, the effective value of the current is calculated, and the difference between the effective value of the current at the current moment and the effective value of the current one power frequency cycle ago is used to calculate the current increment of the first traction network line. The second traction network line is adjacent to the first traction network line. The current increment of the second traction network line is obtained by the same method as that used to obtain the current increment of the first traction network line. If the first traction network line meets the starting conditions, it enters the delay phase and sends a current increment start signal to the second traction network line. If, during the delay period, the current increment of the first traction network line is greater than its current increment setting value, then when the first traction network line receives the current increment start signal sent by the second traction network line, all circuit breakers of the first traction network line will trip. If the second traction network line meets the starting conditions, it enters the delay phase and sends an incremental current start signal to the first traction network line. If, during the delay period, the current increment of the second traction network line is greater than its current increment setting value, then when the second traction network line receives the current increment start signal sent by the first traction network line, all circuit breakers of the second traction network line will trip. The specific start-up condition is: the current increment of the traction network line is greater than its current increment setting value; During the delay phase, the current increment of the traction network line is calculated by subtracting the effective current value of the traction network line at the current moment from the effective current value one power frequency cycle before the start of the delay phase.

2. The method of protection against out-of-phase short circuits in a traction network based on the increment of the current in the adjacent line according to claim 1, characterized in that, The second traction network line is adjacent to the first traction network line, specifically: the first traction network line is connected to the α-phase bus of the traction substation, and the second traction network line is connected to the β-phase bus of the traction substation; or, the first traction network line is connected to the β-phase bus of the traction substation, and the second traction network line is connected to the α-phase bus of the traction substation.

3. The method of protection against out-of-phase short circuits in a traction network based on the increment of the current in the adjacent line according to claim 1, characterized in that, The second traction network line is adjacent to the first traction network line, specifically: the first traction network line is connected to the busbar of the traction substation, and the second traction network line is connected to the busbar of the traction substation adjacent to the first traction substation.

4. The method of protection against out-of-phase short circuits in a traction network based on the increment of the current in the adjacent line according to claim 1, characterized in that, The starting condition is replaced by: the current increment of the traction network line is greater than its current increment setting value, and the ratio of the effective value of the second harmonic of the current to the effective value of the fundamental current is less than the second harmonic blocking setting value.

5. The method of protection against out-of-phase short circuits in a traction network based on the increment of the current in the adjacent line according to claim 1, characterized in that, The traction network line includes a T-line, and the current of the traction network line is the T-line current.

6. The method of protection against out-of-phase short circuits in a traction network based on the increment of the current in the adjacent line according to claim 5, characterized in that, The traction network line also includes the F line, and the current of the traction network line is a combination of the T line current and the F line current.

7. The traction network interphase short-circuit relay protection method based on the current increment of adjacent lines as described in any one of claims 1-6, characterized in that, The current of the first traction network line is collected by: collecting the feeder current at the substation of the first traction network line, or collecting the feeder current at the AT of the first traction network line, or collecting the feeder current at the section of the first traction network line, or collecting the feeder current at the switch of the first traction network line; the current of the second traction network line is collected by: collecting the feeder current at the substation of the second traction network line, or collecting the feeder current at the AT of the second traction network line, or collecting the feeder current at the section of the second traction network line, or collecting the feeder current at the switch of the second traction network line.

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