Anti-fusing protection method for overhead line system of direct-current traction power supply system

Abstract

The invention discloses an anti-fusing protection method for a contact network of a direct current traction power supply system, and the method comprises the steps: dividing working conditions according to different positions, where a running train is parked, of an insulation anchor section joint of the contact network, and carrying out the through current analysis of each working condition, and building a corresponding equivalent circuit model; determining an equivalent circuit by using the equivalent circuit model and combining with an anti-fusing device, and calculating the total ride-through current of the working condition when the running train is stopped and the branch resistance between the pantograph and the contact network insulation anchor section joint of the working condition; the effective current is calculated through the total crossing current and the branch resistance, the effective current is screened by utilizing the contact line fusing boundary condition to serve as the crossing current, the protection proportion is calculated based on the effective current and the crossing current, the anti-fusing device installation scheme is selected, and capacity checking is carried out. The method provided by the invention can ensure safe and reliable operation of the overhead line system when the train is parked in the insulation anchor section joint.

Description

Technical Field

[0001] The present invention relates to the technical field of direct current traction power supply, and in particular to a method for preventing fuse breaking of contact network of a direct current traction power supply system. Background Art

[0002] As a special structure in the contact network, the flexible contact network insulation anchor section joint has important functions such as adjusting the contact network tension, dividing the power supply area to limit the scope of accidents, and facilitating construction and maintenance. However, with the increase in subway passenger volume in recent years, trains sometimes stop in the insulation anchor section during operation. At this time, at the transition point between the working branch and the non-working branch of the contact network, the carbon slide plate of the pantograph and the contact line of a certain anchor section may not have good contact, that is, virtual contact. When a through current passes through, it will cause local overheating of the contact line, which may damage the conductor and cause arcing and burning of the wire, endangering driving safety. Summary of the invention

[0003] In view of this, the purpose of the present invention is to provide a method for preventing fuse blowing of the contact network of a DC traction power supply system. By calculating the current conduction capacity of the fuse protection device required when the train stops, the installation plan of the anti-fuse device is selected and the installation capacity of the equipment is checked to ensure that the contact network can operate safely and reliably when the train stops in the insulating anchor section joint.

[0004] In a first aspect, an embodiment of the present invention provides a method for preventing fuse breaking of a contact network of a DC traction power supply system, comprising: When a moving train stops at a contact network insulation anchor section joint and there is a through current at the contact network insulation anchor section joint, the working conditions are divided according to different positions of the contact network insulation anchor section joint where the moving train stops, and a corresponding contact network insulation anchor section joint equivalent circuit model is established by analyzing the through current for each of the working conditions; The equivalent circuit model of the contact network insulation anchor section joint is used in combination with the anti-fuse device to determine the equivalent circuit of each working condition, and the total through current I of the working condition when the running train stops is calculated according to the equivalent circuit. T , and the branch resistance R between the pantograph and the contact network insulation anchor section joint under the working condition P ; The total through current I T and the branch resistance R P Calculate the effective current I P , using the contact wire fusing boundary condition to screen the effective current I P As the traversable current, based on the effective current I P and the protection ratio η calculated based on the traversable current; Based on the protection ratio η, an anti-fuse device installation plan is selected and a capacity check is performed.

[0005] Preferably, according to the different positions where the running train stops at the catenary insulation overlap, it is divided into a first working condition, a second working condition, a third working condition, a fourth working condition, and a fifth working condition.

[0006] Preferably, by analyzing the through-current of the second working condition, the third working condition, and the fourth working condition, the second working condition is divided into a first sub-working condition and a second sub-working condition, the third working condition is divided into a third sub-working condition and a fourth sub-working condition, and the fourth working condition is divided into a fifth sub-working condition and a sixth sub-working condition.

[0007] Preferably, the branch resistance R P includes the contact resistance between the pantograph and the working branch of the catenary insulation overlap, the virtual connection resistance between the pantograph and the non-working branch of the catenary insulation overlap, and the resistance of the carbon slide plate of the pantograph between the first catenary contact wire and the second catenary contact wire.

[0008] Preferably, the catenary fuse boundary condition is the tension applied to the catenary and the temperature of the catenary under this tension.

[0009] Preferably, in setting the catenary fuse boundary condition, the limit value of the tension applied to the catenary is 12 kN, and the limit value of the temperature of the catenary under this tension is 150 °C.

[0010] Preferably, through the total through-current I T and the branch resistance R P calculate the effective current I P , use the catenary fuse boundary condition to screen the effective current I P as the allowable through-current, and calculate the protection ratio η based on the effective current I P and the allowable through-current, including: Determine the numerical range of the branch resistance R P ; Determine the value of the total through-current I T ; Combine the numerical range of the branch resistance R P and the value of the total through-current I T , and use the nodal voltage method to calculate the effective current I P passing through the branch resistance R P ; Use the catenary fuse boundary condition to screen the effective current I P , to obtain the allowable through-current; Based on the effective current I PCalculate the protection ratio η based on the traversable current and the like.

[0011] Preferably, the traversable current with the largest value is the maximum traversable current I TC , and the maximum traversable current I TC The corresponding branch resistance R P is the maximum traversable resistance R PC ; if the maximum traversable current I TC corresponds to multiple branch resistances R P , then select the branch resistance R P with the smallest value among the multiple branch resistances R P as the maximum traversable resistance R PC .

[0012] Preferably, when the value of the protection ratio η is greater than 95%, select the anti-fusing device installation scheme to install the anti-fusing device.

[0013] Preferably, when selecting the anti-fusing device installation scheme, initially set the device branch resistances R S1 , device branch resistance R S2 , device branch resistance R S3 of the anti-fusing device S1, anti-fusing device S2, and anti-fusing device S3 to all be 0.0044 mΩ, and the rated current-carrying capacity of the contactors corresponding to the device branch resistance R S1 , the device branch resistance R S2 , the device branch resistance R S3 is I N = 2000 A.

[0014] The embodiments of the present invention bring the following beneficial effects: This embodiment discloses a method for anti-fusing protection of the catenary in a DC traction power supply system. It combines the established equivalent circuit model of the catenary insulating anchor section joint with the anti-fusing device installation scheme to determine the equivalent circuit under each working condition, calculates the maximum traversable current, maximum traversable resistance, and protection ratio according to the equivalent circuit, selects the anti-fusing device installation scheme for the working condition where the running train stops based on the maximum traversable current, maximum traversable resistance, and protection ratio, and conducts capacity verification.

[0015] On the one hand, this method can completely eliminate the vehicle no-parking area of the catenary, is friendly to operation, and meets the actual needs of trains running at high density during peak hours to stop at the insulating anchor section joint; on the other hand, it significantly improves the safety and reliability of the catenary. Especially when dealing with large passenger flows and emergencies, it can provide more effective traction power supply guarantee.

[0016] Other features and advantages of the present invention will be set forth in the following description, and in part will be obvious from the description, or may be learned by practice of the present invention. The objectives and other advantages of the present invention are realized and attained by the structure particularly pointed out in the specification, claims as well as the drawings.

[0017] To make the above objectives, features and advantages of the present invention more comprehensible, the following specific preferred embodiments are given and detailed descriptions are made in conjunction with the accompanying drawings as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0019] Figure 1 It is a schematic flowchart of a method for preventing the catenary from fusing in a DC traction power supply system provided by an embodiment of the present invention; Figure 2 It is a schematic diagram of the conversion between the non-working branch and the working branch of the catenary insulating anchor section joint in a method for preventing the catenary from fusing in a DC traction power supply system provided by an embodiment of the present invention; Figure 3 It is a schematic diagram of the position where a running train stops at the catenary insulating anchor section joint in a method for preventing the catenary from fusing in a DC traction power supply system provided by an embodiment of the present invention; Figure 4 It is a wiring schematic diagram of a fusing prevention device in a method for preventing the catenary from fusing in a DC traction power supply system provided by an embodiment of the present invention; Figure 5 It is a schematic diagram of the analysis of the through current in the second working condition of a method for preventing the catenary from fusing in a DC traction power supply system provided by an embodiment of the present invention; Figure 6 It is an equivalent circuit model diagram of the catenary insulating anchor section joint in the first sub-working condition of a method for preventing the catenary from fusing in a DC traction power supply system provided by an embodiment of the present invention; Figure 7 It is an equivalent circuit model diagram of the catenary insulating anchor section joint in the second sub-working condition of a method for preventing the catenary from fusing in a DC traction power supply system provided by an embodiment of the present invention; Figure 8 It is an equivalent circuit model diagram of the catenary insulating anchor section joint in the third sub-working condition of a method for preventing the catenary from fusing in a DC traction power supply system provided by an embodiment of the present invention; Figure 9The equivalent circuit model diagram of the catenary insulation anchor section joint for the fourth working condition of a catenary anti-fusing protection method provided by an embodiment of the present invention; Figure 10 The equivalent circuit model diagram of the catenary insulation anchor section joint for the fifth working condition of a catenary anti-fusing protection method provided by an embodiment of the present invention; Figure 11 The equivalent circuit model diagram of the catenary insulation anchor section joint for the sixth working condition of a catenary anti-fusing protection method provided by an embodiment of the present invention. Detailed implementation manners

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0021] For ease of understanding of this embodiment, in combination with Figure 1 A catenary anti-fusing protection method disclosed in an embodiment of the present invention will be introduced in detail. Embodiment 1

[0022] This embodiment provides a catenary anti-fusing protection method for a DC traction power supply system, including: S1: When a running train stops at the catenary insulation anchor section joint and there is a cross current in the catenary insulation anchor section joint, different working conditions are divided according to the different positions where the running train stops at the catenary insulation anchor section joint. By analyzing the cross current for each working condition, an equivalent circuit model of the catenary insulation anchor section joint is established.

[0023] Among them, this embodiment will combine Figures 2 to 11 Analyze the catenary wire fusing mechanism when the running train stops at different positions of the non-insulated anchor section joint of the catenary.

[0024] Figure 2 It is a schematic diagram of the conversion between the non-working branch and the working branch of the catenary insulation anchor section joint. When the train stops in the catenary insulation anchor section area, as Figure 2 shown, at the conversion point between the working branch and the non-working branch of the catenary insulation anchor section joint, there may be a non-good contact phenomenon, that is, a virtual connection, between the carbon skate of the pantograph and the catenary wire of a certain anchor section; when there is a cross current passing through, it will cause local overheating of the catenary wire, with the risk of damaging the wire, and accompanied by the situation of burning arcs, endangering the safety of train operation.

[0025] Figure 3 It is a schematic diagram of the position where a running train stops at the catenary insulating section joint. Figure 3 In it, taking the running train moving from left to right as an example, the first section and the second section are catenary sections that are insulated from each other. The AF area is the catenary insulating section joint. In the AF area, point A is the starting point of the second section; point B is the starting point where the second section switches from the non-working support to the working support, and it is also the starting point where the first section switches from the working support to the non-working support; point C is the connection point where the feeding cable of the traction substation is connected to the first section; point D is the connection point where the feeding cable of the traction substation is connected to the second section; point E is the end point where the second section switches from the non-working support to the working support, and it is also the end point where the first section switches from the working support to the non-working support; point F is the end point of the first section. K1 and K2 are normally closed catenary feeding switches respectively, and K3 is a normally open catenary connection switch. S1, S2, and S3 are anti-fusing devices installed between two catenary insulating section joints respectively, which have the ability to switch on and off under load. For the wiring schematic diagram of the anti-fusing device, see Figure 4 ; among them, the anti-fusing device S1 is installed between the outgoing sides of the feeding switch K1 and the feeding switch K2, the anti-fusing device S2 is installed at point A of the first section and the second section, and the anti-fusing device S3 is installed at point F of the first section and the second section. L1 is a running train parked at the catenary insulating section joint, and the running train L1 can stop at any position in the AF section; L2 is a train that is taking current and exists at a certain distance to the right of the catenary insulating section joint, that is, the current-taking train L2; L3 is a train that may be in electric braking at a certain distance to the left of the catenary insulating section joint, that is, the regenerative braking train L3.

[0026] Combined with Figure 3 , preferably, it is divided into a first working condition, a second working condition, a third working condition, a fourth working condition, and a fifth working condition according to the different positions where the running train stops at the catenary insulating section joint.

[0027] In this embodiment, the settings of the first working condition, the second working condition, the third working condition, the fourth working condition, and the fifth working condition are as follows: When the running train L1 stops at any position from point A to point B (including point B), it is set as the first working condition; when the running train L1 stops at any position from point B to point C (excluding point B, including point C), it is set as the second working condition; when the running train L1 stops at any position from point C to point D (excluding point C and point D), it is set as the third working condition; when the running train L1 stops at any position from point D to point E (including point D, excluding point E), it is set as the fourth working condition; when the running train L1 stops at any position from point E to point F (including point E), it is set as the fifth working condition; Among them, when the running train L1 is in the first working condition and the fifth working condition, since there is no virtual connection between the non-working branch of the catenary and the pantograph, no cross current flowing through the pantograph will be generated. At this time, there is no need to set the anti-fusing device S1, anti-fusing device S2, and anti-fusing device S3. Therefore, there is no need to analyze the cross current for the first working condition and the fifth working condition, and only the second working condition, the third working condition, and the fourth working condition need to be analyzed for cross current.

[0028] This embodiment will be combined with Figure 5 , and the second working condition will be taken as an example to analyze the cross current of the second working condition. Figure 5 For the schematic diagram of the cross current analysis of the second working condition, see Figure 5 , the total cross current I T of the second working condition is the first cross current I T1 , the second cross current I T2 , and the third cross current I T3 The sum, that is, I T = I T1 + I T2 + I T3 .

[0029] Figure 5 In T1 , the flow path of the first cross current I is as follows: starting from the DC bus of the traction substation, flowing through the online switch K1, online cable, first anchor section, pantograph, second anchor section, and finally flowing to the current-taking train L2; T2 The flow path of the second cross current I is as follows: starting from the regenerative braking train L3, flowing through the pantograph and the second anchor section, and finally flowing to the current-taking train L2; T3 The flow path of the third cross current I

[0030] is as follows: starting from the regenerative braking train L3, flowing through the first anchor section, online cable, online switch K1, DC bus of the traction substation, online switch K2, online cable, second anchor section, and finally flowing to the current-taking train L2.

[0031] In this embodiment, taking the second working condition as an example, the second working condition can be further divided into the first sub-working condition and the second sub-working condition, and the principle is as follows: When there is no regenerative braking train L3, the situation at this time is the first sub-working condition; when there is a regenerative braking train L3, a regenerative braking current I3 will be generated and sent back to the catenary, and the situation at this time is the second sub-working condition.

[0032] The principle and steps of dividing the third working condition into the third sub - working condition and the fourth sub - working condition, and dividing the fourth working condition into the fifth sub - working condition and the sixth sub - working condition are roughly the same as those of dividing the second working condition into the first sub - working condition and the second sub - working condition, so they will not be elaborated here.

[0033] Based on this, an equivalent circuit model of the catenary insulation anchor section joint can be established according to the working conditions. The equivalent circuit model diagrams of the catenary insulation anchor section joint for each working condition are as Figures 6 to 11 shown.

[0034] Figure 6 is the equivalent circuit model diagram of the catenary insulation anchor section joint for the first sub - working condition. Among them, I T is the total passing - through current; R SS is the equivalent resistance inside the traction substation; R K1 is the resistance of the feeding cable connected to the feeding switch K1; R K2 is the resistance of the feeding cable connected to the feeding switch K2; R P is the resistance of the branch between the pantograph and the catenary insulation anchor section joint; R S1 is the resistance of the device branch of the anti - fusing device S1; R S2 is the resistance of the device branch of the anti - fusing device S2; R S3 is the resistance of the device branch of the anti - fusing device S3; For the equivalent circuit model without installing the anti - fusing device, or without installing all of the above 3 anti - fusing devices, the resistance of the device branches R S1 、R S2 、R S3 are set to infinity. Among them, Figure 3 is the wiring schematic diagram of the anti - fusing device.

[0035] In addition, Figure 6 in, the general symbol R ijk is used to represent the resistances of each section of the catenary. In R ijk , i and j respectively represent the starting point and the ending point of the catenary section. i and j are A, B, C, D, E, F, P, corresponding to point A, point B, point C, point D, point E, point F, and point P respectively, where point P is the position of the pantograph when the running train stops; k is 1 or 2, representing the first anchor section or the second anchor section respectively. Exemplarily, Figure 6 in, R BP1 is the resistance of the first anchor section from point B to point P.

[0036] Figures 7 to 11 are respectively the equivalent circuit model diagrams of the catenary insulation anchor section joint for the second sub - working condition, the third sub - working condition, the fourth sub - working condition, the fifth sub - working condition, and the sixth sub - working condition. Among them, Figures 7 to 11The meanings of the resistors in are the same as those in Figure 6 and will not be elaborated here.

[0037] S2: Using the equivalent circuit model of the catenary insulating anchor section joint, combined with the anti-fusing device to determine the equivalent circuit of each working condition, and calculating the total through current I of the train when it stops according to the equivalent circuit T , and the branch resistance R between the pantograph and the catenary insulating anchor section joint in the working condition P .

[0038] It should be noted that in this embodiment, the total through current is obtained through the vehicle type formation. Since the vehicle types are different, the values of their starting currents are different. Therefore, the values of the total through current generated at this time will also be different.

[0039] Preferably, the branch resistance R P includes the contact resistance between the pantograph and the working branch of the catenary insulating anchor section joint, the virtual connection resistance between the pantograph and the non-working branch of the catenary insulating anchor section joint, and the resistance of the carbon slide plate of the pantograph between the first catenary contact wire and the second catenary contact wire.

[0040] Among them, the virtual connection resistance between the pantograph and the non-working branch of the catenary insulating anchor section joint is the transition resistance at the virtual connection between the pantograph and the non-working branch of the catenary insulating anchor section joint. Its value can be obtained through calculation. However, due to influencing factors such as the non-fixed lifting force of the pantograph, the random parking position of the running train, and the large influence of wind force and air humidity, it is difficult to simulate the full-scene and full-position of the parking position of the running train.

[0041] Therefore, in this embodiment, the value range of the branch resistance R between the pantograph and the catenary insulating anchor section joint when the train stops is obtained through a large number of on-site measured data. Its advantage is that it can simulate the random parking position of the running train, so as to better determine the loop impedance between the pantograph and the catenary insulating anchor section joint; among them, through the measured data, when the value range of the lifting force of the pantograph is 80N~120N, the normal value of the general branch resistance R P is 0.1mΩ~100mΩ. P

[0042] S3: Calculating the effective current I T through the total through current I P and the branch resistance R P , screening the effective current I using the catenary fusing boundary condition P as the traversable current, and calculating the protection ratio η based on the effective current I P and the traversable current.

[0043] Preferably, the fuse boundary condition of the contact wire is the tension applied to the contact wire and the temperature of the contact wire under this tension.

[0044] In this embodiment, the temperature of the contact wire can be calculated based on vehicle parameters. The vehicle parameters are obtained based on the load processes of typical train traction and braking. The vehicle parameters can determine the current required for L2 traction of the current-taking train and the magnitude and duration of the current fed back from the L3 inverter of the regenerative braking train to the catenary, and then calculate the heating condition of the virtual connection part between the pantograph and the insulating section joint of the catenary to obtain the temperature of the contact wire.

[0045] Furthermore, in setting the fuse boundary condition of the contact wire, the limit value of the tension applied to the contact wire is 12 kN, and the limit value of the temperature of the contact wire under this tension is 150 °C.

[0046] Preferably, calculate the effective current I T through the total through-current I P and the branch resistance R P . Use the fuse boundary condition of the contact wire to screen the effective current I P as the allowable through-current. Based on the effective current I P and the allowable through-current, calculate the protection ratio η, including: S101: Determine the numerical range of the branch resistance R P .

[0047] In this embodiment, in S101, by expanding the verification range of the branch resistance R P , determine the numerical range of the branch resistance R P so as to minimize the influence of extreme conditions on the current-carrying capacity of the system.

[0048] Furthermore, the numerical range of the branch resistance R P is R Pmin ~R Pmax , where R Pmin is the minimum value of the branch resistance R P , and R Pmax is the maximum value of the branch resistance R P . If the numerical range of the branch resistance R is divided with P as the fixed step size, then n values of the branch resistance R P can be obtained, including: R Pmax , , , ……, , , R Pmin .

[0049] Even further, the value of n is 20 or 30.

[0050] S102: Determine the total through - current I T value.

[0051] In this embodiment, in S102, the total through - current I T1 is determined by the possible maximum values of the first through - current I T2 , the second through - current I T3 , and the third through - current I T value.

[0052] Furthermore, the value of the total through - current I T is I Tmax ; if is used as the step size, and the maximum value of the total through - current I T is I Tmax is divided, m values of the total through - current I T can be obtained, including: , , , ……, , , I Tmax .

[0053] Furthermore, the value of m is 20.

[0054] S103: Combine the value range of the branch resistance R P and the value of the total through - current I T , and use the nodal voltage method to calculate the effective current I P passing through the branch resistance R P .

[0055] Exemplarily, in S103, the method of combining the value range of the branch resistance R P and the value of the total through - current I T , and using the nodal voltage method to calculate the effective current I P passing through the branch resistance R P is as follows: When the value of the total through - current I T is I Tmax , the values of the branch resistance R P are R Pmax , , , ……, , , R Pmin , and use the nodal voltage method to calculate the effective current I P corresponding to the above values for the branch resistance R P ; When the total through - current I T has a value of and the branch resistance R P also has a value of R Pmax , , , ……, , , R Pmin , use the node - voltage method to calculate the effective current I P corresponding to the branch resistance R P ; And so on, it is possible to use the node - voltage method to calculate the effective current I T corresponding to all branch resistances R P for all values of the total through - current I P . At this time, the number of values of the effective current I P is , where the unit of the effective current I P is A.

[0056] S104: Use the catenary fusing boundary condition to screen the effective current I P to obtain the traversable current.

[0057] In this embodiment, in S104, the method of using the catenary fusing boundary condition to screen the effective current I P to obtain the traversable current includes: judging whether the tension and temperature of the catenary are less than the limit value of the catenary fusing boundary condition. If so, then screen the effective current I P of the catenary at this time as the traversable current.

[0058] Furthermore, the traversable current with the largest value is the maximum traversable current I TC , and the branch resistance R TC corresponding to the maximum traversable current I P is the maximum traversable resistance R PC ; if the maximum traversable current I TC corresponds to multiple branch resistances R P , then select the branch resistance R P with the smallest value among the multiple branch resistances R P as the maximum traversable resistance R PC .

[0059] S105: Calculate the protection ratio η based on the effective current I P and the traversable current.

[0060] In this embodiment, in S105, the expression of the protection ratio η is:

[0061] In the formula, f is the number of values of the traversable current, is the number of values of the effective current I P .

[0062] S4: Select the anti-fuse device installation plan based on the protection ratio η, and conduct capacity verification.

[0063] Among them, the anti-fuse device installation plan is the plan to install the anti-fuse device between two catenary insulating anchor section joints; the capacity verification is to evaluate and verify the transportation capacity of the catenary to determine whether it can meet the expected transportation requirements.

[0064] Specifically, the anti-fuse device installation plan is shown in Table 1. In Table 1, "×" means not installing the anti-fuse device, and "√" means installing the anti-fuse device. Exemplarily, Plan 3 means not installing anti-fuse device S1, installing anti-fuse device S2, and not installing anti-fuse device S3; Plan 5 means installing anti-fuse device S1, installing anti-fuse device S2, and not installing anti-fuse device S3.

[0065] In Table 1, further, Plan 1 is used to compare the anti-fuse effects of other installation plans.

[0066] Table 1. Anti-fuse device installation plan for catenary insulating anchor section joints

[0067] Preferably, when the value of the protection ratio η is greater than 95%, select the anti-fuse device installation plan to install the anti-fuse device.

[0068] Among them, when the value of the protection ratio η is greater than 95%, the selected anti-fuse device installation plan can effectively ensure the safe and reliable operation of the catenary when the train stops within the insulating anchor section joint. If there are multiple selectable anti-fuse device installation plans when the value of the protection ratio η is greater than 95% and other parameters or conditions are the same, then at this time, the anti-fuse device installation plan can be selected by combining the two aspects of strong economy and high protection rate.

[0069] In addition, if the value of the protection ratio η is very low, the current-carrying capacity of the contactor corresponding to the device branch resistance can be considered to be increased, for example, a contactor with a rated current-carrying capacity I N larger is selected; at the same time, the device branch resistance of the anti-fuse device is reduced, for example, the cross-sectional area of the cable is increased.

[0070] Preferably, when selecting the anti-fuse device installation plan, first set the device branch resistances R S1 of the anti-fuse device S1, the anti-fuse device S2, and the anti-fuse device S3, S2, the resistance R of the device branch S3 has a value of 0.0044 mΩ. The rated current-carrying capacity of the contactor corresponding to the device branch resistance R S1 , the device branch resistance R S2 , the device branch resistance R S3 is I N = 2000 A.

[0071] In this embodiment, the reason for setting the rated current-carrying capacity of the contactor corresponding to each device branch resistance to be I N = 2000 A includes: According to the measurement of the actual project, it shows that the short-time maximum current taken by a running train, that is, the instantaneous maximum current when a running train starts, is generally within 4000 A. The set rated current-carrying capacity I N = 2000 A can fully meet the various current-carrying capacities required by the anti-fusing device installation scheme selected in this embodiment.

[0072] It should be noted that in this article, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0073] Finally, it should be noted that: the above-described embodiments are only specific embodiments of the present invention, used to illustrate the technical solutions of the present invention, rather than to limit it. The protection scope of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: any person skilled in the art within the technical scope disclosed by the present invention can still modify the technical solutions described in the foregoing embodiments, or can easily think of changes, or make equivalent replacements for some of the technical features; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims

1. A method for protecting the contact network from fuse-breaking in a DC traction power supply system, characterized in that: include: When a moving train stops at a contact network insulation anchor section joint and there is a through current at the contact network insulation anchor section joint, the working conditions are divided according to different positions of the contact network insulation anchor section joint where the moving train stops, and a corresponding contact network insulation anchor section joint equivalent circuit model is established by analyzing the through current for each of the working conditions; The equivalent circuit model of the contact network insulation anchor section joint is used in combination with the anti-fuse device to determine the equivalent circuit of each working condition, and the total through current I of the working condition when the running train stops is calculated according to the equivalent circuit. T , and the branch resistance R between the pantograph and the contact network insulation anchor section joint under the working condition P ; The total through current I T and the branch resistance R P Calculate the effective current I P , using the contact wire fusing boundary condition to screen the effective current I P As the traversable current, based on the effective current I P and the protection ratio η calculated based on the traversable current; Based on the protection ratio η, an anti-fuse device installation plan is selected and a capacity check is performed.

2. A method for preventing fuse breaking of contact network in a DC traction power supply system according to claim 1, characterized in that: According to the different positions of the contact network insulation anchor section joint where the moving train stops, it is divided into the first working condition, the second working condition, the third working condition, the fourth working condition and the fifth working condition.

3. A method for preventing fuse breaking of contact network of a DC traction power supply system according to claim 2, characterized in that: By performing through-current analysis on the second operating condition, the third operating condition, and the fourth operating condition, the second operating condition is divided into a first sub-operating condition and a second sub-operating condition, the third operating condition is divided into a third sub-operating condition and a fourth sub-operating condition, and the fourth operating condition is divided into a fifth sub-operating condition and a sixth sub-operating condition.

4. A method for preventing fuse breaking of contact network in a DC traction power supply system according to claim 1, characterized in that: The branch resistance R P It includes the contact resistance of the pantograph and the working branch of the contact network insulation anchor section joint, the virtual connection resistance of the pantograph and the non-working branch of the contact network insulation anchor section joint, and the resistance of the carbon slide plate of the pantograph between the first anchor section contact line and the second anchor section contact line.

5. A method for preventing fuse breaking of contact network in a DC traction power supply system according to claim 1, characterized in that: The contact wire fusing boundary condition is the tension on the contact wire and the temperature of the contact wire under the tension.

6. A method for protecting the contact network from fuse-breaking of a DC traction power supply system according to claim 5, characterized in that: In setting the contact wire fusing boundary condition, the limit value of the tension applied to the contact wire is 12 kN, and the limit value of the temperature of the contact wire under the tension is 150° C.

7. A method for protecting the contact network from fuse-breaking of a DC traction power supply system according to claim 1, characterized in that: The total through current I T and the branch resistance R P Calculate the effective current I P , using the contact wire fusing boundary condition to screen the effective current I P As the traversable current, based on the effective current I P and the traversable current to calculate the protection ratio η, comprising: Determine the branch resistance R P The numerical range of Determine the total through current I T The value of Combined with the branch resistor R P The value range and the total through current I T The value of the branch resistance R is calculated using the node voltage method. P The effective current I P ; The effective current I is screened using the contact line fusing boundary condition P , obtaining the traversable current; Based on the effective current I P and the crossable current, and calculate the protection ratio η.

8. A method for preventing fuse breaking of contact network in a DC traction power supply system according to claim 7, characterized in that: The maximum traversable current is the maximum traversable current I TC , the maximum current that can be passed through I TC The corresponding branch resistance R P The maximum traversable resistance R PC If the maximum current that can be passed through I TC Corresponding to the plurality of branch resistors R P , then select multiple branch resistors R P The branch resistance R with the smallest value P As the maximum traversable resistance R PC .

9. A method for protecting the contact network from fuse-breaking of a DC traction power supply system according to claim 1, characterized in that: When the value of the protection ratio η is greater than 95%, the anti-fuse device installation scheme is selected to install the anti-fuse device.

10. A method for protecting the contact network from fuse-breaking of a DC traction power supply system according to claim 1, characterized in that: When selecting the anti-fuse device installation scheme, the device branch resistance R of the anti-fuse device S1, the anti-fuse device S2, and the anti-fuse device S3 are set for the first time. S1 , Device branch resistance R S2 , Device branch resistance R S3 The value of is 0.0044mΩ, and the branch resistance R S1 , the device branch resistance R S2 , the device branch resistance R S3 The rated current carrying capacity of the corresponding contactor is I N =2000A.

Images