A method for preventing fuse-breaking of contact network in DC traction power supply system

Abstract

The present invention discloses a method for protecting the catenary from fuse-flash protection in a DC traction power supply system. The method comprises: dividing operating conditions according to different positions of a moving train at a catenary insulation anchor joint, establishing a corresponding equivalent circuit model by analyzing the through-current for each operating condition; utilizing the equivalent circuit model in conjunction with an anti-fuse device to determine the equivalent circuit, and calculating the total through-current for the operating condition in which the moving train is stopped, as well as the branch resistance between the pantograph and the catenary insulation anchor joint in the operating condition; calculating the effective current based on the total through-current and the branch resistance, screening the effective current as the through-current using the contact wire fusing boundary condition, calculating a protection ratio based on the effective current and the through-current, selecting an anti-fuse device installation scheme, and performing capacity verification. The method provided by the present invention can ensure safe and reliable operation of the catenary when a train is stopped within an insulation anchor joint.

Description

Technical Field

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

[0002] As a special structure in the catenary, the flexible catenary insulation anchor section joint has important functions such as adjusting the catenary 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 within the insulation anchor section during operation. In this case, at the transition point between the working and non-working branches of the catenary, the carbon plate of the pantograph and the contact wire of a certain anchor section may not be in good contact, that is, a false contact. When a through current passes through, it will cause local overheating of the contact wire, risking damage to the conductor, and accompanied by 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 conducting 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 blown protection of a contact network in a DC traction power supply system, comprising:

[0005] When a moving train stops at a contact network insulation anchor section joint and a through-current exists at the contact network insulation anchor section joint, operating conditions are divided according to different positions of the contact network insulation anchor section joint at which 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 operating conditions;

[0006] The equivalent circuit model of the catenary 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 moving train stops is calculated based on 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 ;

[0007] The total through current I T and the branch resistance R P Calculate the effective current I P , using the contact line fusing boundary condition to screen the effective current I P As the cross-current, based on the effective current I P and the protection ratio η calculated based on the cross-current;

[0008] Based on the protection ratio η, an anti-fuse device installation plan is selected and a capacity check is performed.

[0009] Preferably, the operating conditions are divided into a first operating condition, a second operating condition, a third operating condition, a fourth operating condition and a fifth operating condition according to the different positions of the contact network insulation anchor section joint at which the moving train stops.

[0010] Preferably, 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.

[0011] Preferably, the branch resistor R P It includes the contact resistance between the pantograph and the working branch of the contact network insulation anchor section joint, the virtual connection resistance between 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.

[0012] Preferably, the contact wire fusing boundary condition is the tension applied to the contact wire and the temperature of the contact wire under the tension.

[0013] Preferably, 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.

[0014] Preferably, the total through current I T and the branch resistance R P Calculate the effective current I P , using the contact line fusing boundary condition to screen the effective current I P As the traversable current, based on the effective current I P and the cross-current to calculate the protection ratio η, comprising:

[0015] Determine the branch resistance R P The numerical range of

[0016] Determine the total through current I T The value of

[0017] Combined with the branch resistor R P The numerical 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 ;

[0018] The effective current I is screened using the contact line fusing boundary condition. P , obtaining the traversable current;

[0019] Based on the effective current I P and the cross-current, and calculate the protection ratio η.

[0020] Preferably, the maximum traversable current is the maximum traversable current I TC , the maximum passable current I TC The corresponding branch resistance R P That is the maximum traversable resistance R PC If the maximum current that can pass 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 .

[0021] Preferably, 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.

[0022] Preferably, 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 values ​​of are all 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.

[0023] The embodiments of the present invention bring the following beneficial effects:

[0024] This embodiment discloses a method for preventing fuse blowout of the contact network of a DC traction power supply system. An established equivalent circuit model of the contact network insulation anchor section joint is combined with the installation plan of the anti-fuse device to determine the equivalent circuit under various working conditions. The maximum passable current, maximum passable resistance and protection ratio are calculated based on the equivalent circuit. The installation plan of the anti-fuse device for the working condition when a moving train stops is selected based on the maximum passable current, maximum passable resistance and protection ratio, and the capacity verification is performed.

[0025] On the one hand, this method can completely eliminate the vehicle no-parking zones on the contact network, which is friendly to operations and suitable for the actual needs of high-density trains stopping at the insulated anchor section joints during peak hours in the morning and evening; on the other hand, it can significantly improve the safety and reliability of the contact network, especially when dealing with large passenger flows and emergencies, and can provide more effective traction power guarantees.

[0026] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or understood by practicing the present invention. The purposes and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 A schematic flow chart of a method for preventing fuse blown in a contact network of a DC traction power supply system provided by an embodiment of the present invention;

[0030] Figure 2 A schematic diagram of the conversion between the non-working branch and the working branch of the contact network insulation anchor section joint of a DC traction power supply system contact network anti-fuse protection method provided by an embodiment of the present invention;

[0031] Figure 3 A schematic diagram of the position of a moving train stopped at a contact network insulation anchor section joint in a method for preventing fuse blown protection of a DC traction power supply system provided by an embodiment of the present invention;

[0032] Figure 4 A wiring diagram of an anti-fuse device for a method for protecting a contact network of a DC traction power supply system provided by an embodiment of the present invention;

[0033] Figure 5 A schematic diagram of a through-current analysis of a second operating condition of a method for preventing fuse-breaking protection of a direct current traction power supply system catenary provided by an embodiment of the present invention;

[0034] Figure 6An equivalent circuit model diagram of the contact network insulation anchor section joint of the first sub-operating condition of a method for preventing fuse-breaking of a contact network in a DC traction power supply system provided by an embodiment of the present invention;

[0035] Figure 7 An equivalent circuit model diagram of the contact network insulation anchor section joint of the second sub-operating condition of a method for preventing fuse-breaking of a contact network in a DC traction power supply system provided by an embodiment of the present invention;

[0036] Figure 8 An equivalent circuit model diagram of the contact network insulation anchor section joint of the third sub-operating condition of a method for preventing fuse-breaking of a contact network in a DC traction power supply system provided by an embodiment of the present invention;

[0037] Figure 9 An equivalent circuit model diagram of the contact network insulation anchor section joint of the fourth sub-operating condition of a method for preventing fuse blown in a DC traction power supply system contact network provided by an embodiment of the present invention;

[0038] Figure 10 An equivalent circuit model diagram of the contact network insulation anchor section joint of the fifth sub-operating condition of a method for preventing fuse blown in a DC traction power supply system contact network provided by an embodiment of the present invention;

[0039] Figure 11 An equivalent circuit model diagram of the contact network insulation anchor section joint of the sixth sub-operating condition of a DC traction power supply system contact network anti-fuse protection method provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0041] To facilitate understanding of this embodiment, Figure 1 A method for preventing fuse blowing of a contact network in a DC traction power supply system disclosed in an embodiment of the present invention is introduced in detail. Example 1

[0042] This embodiment provides a method for preventing fuse blown protection of a contact network in a DC traction power supply system, including:

[0043] S1: When a moving train stops at the 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 the different positions of the moving train at the contact network insulation anchor section joint. By analyzing the through current for each working condition, the corresponding contact network insulation anchor section joint equivalent circuit model is established.

[0044] Among them, this embodiment will combine Figures 2 to 11 The contact wire fusing mechanism is analyzed when a moving train stops at different positions of the contact network non-insulated anchor section joint.

[0045] Figure 2 The diagram for the conversion between the non-working branch and the working branch of the contact network insulation anchor section joint is shown in the figure. Figure 2 As shown in the figure, at the transition point between the working branch and the non-working branch of the contact network insulation anchor section joint, the carbon slide plate of the pantograph and the contact line of a certain anchor section may have poor contact, that is, false contact; when a through current passes through, it will cause local overheating of the contact line, with the risk of damaging the conductor, and accompanied by burning arcs, endangering driving safety.

[0046] Figure 3 This is a schematic diagram of the position of a moving train stopping at the contact network insulation anchor section joint. Figure 3 In the example of a train moving from left to right, the first anchor section and the second anchor section are anchor sections insulated from each other in the contact network;

[0047] The AF area is the contact network insulation anchor section joint. In the AF area, point A is the starting point of the second anchor section; point B is the starting point of the second anchor section from the non-working branch to the working branch, and is also the starting point of the first anchor section from the working branch to the non-working branch; point C is the point where the traction substation's online cable is connected to the online point of the first anchor section; point D is the point where the traction substation's online cable is connected to the online point of the second anchor section; point E is the end point of the second anchor section from the non-working branch to the working branch, and is also the end point of the first anchor section from the working branch to the non-working branch; point F is the end point of the first anchor section;

[0048] K1 and K2 are normally closed contact network switches, and K3 is normally open contact network switch;

[0049] S1, S2, and S3 are fuse-proof devices installed between the joints of the two sections of the contact network insulation anchor section, which have the ability to open and close the switch under load. For the wiring diagram of the fuse-proof device, see Figure 4 Among them, the anti-fuse device S1 is installed between the outgoing line sides of the online switch K1 and the online switch K2, the anti-fuse device S2 is installed at point A of the first anchor section and the second anchor section, and the anti-fuse device S3 is installed at point F of the first anchor section and the second anchor section;

[0050] L1 is a moving train parked at the contact network insulation anchor section joint. The moving train L1 can stop at any position in the AF section; L2 is a train that is located a certain distance to the right of the contact network insulation anchor section joint and is currently drawing current, that is, the drawing current train L2; L3 is a train that is located a certain distance to the left of the contact network insulation anchor section joint and may be currently being electrically braked, that is, the regenerative braking train L3.

[0051] Combine Figure 3 Preferably, the operating conditions are divided into the first operating condition, the second operating condition, the third operating condition, the fourth operating condition and the fifth operating condition according to the different positions of the moving train stopping at the contact network insulation anchor section joint.

[0052] In this embodiment, the settings for the first operating condition, the second operating condition, the third operating condition, the fourth operating condition, and the fifth operating condition are as follows:

[0053] When the train L1 stops at any position between point A and point B (including point B), it is set as the first operating condition; when the train L1 stops at any position between point B and point C (excluding point B, including point C), it is set as the second operating condition; when the train L1 stops at any position between point C and point D (excluding points C and D), it is set as the third operating condition; when the train L1 stops at any position between point D and point E (including point D, excluding point E), it is set as the fourth operating condition; when the train L1 stops at any position between point E and point F (including point E), it is set as the fifth operating condition;

[0054] Among them, when the running train L1 is in the first working condition and the fifth working condition, since the non-working branch of the contact network is not loosely connected with the pantograph, no through-current flowing through the pantograph is generated. At this time, there is no need to set the anti-fuse device S1, the anti-fuse device S2, and the anti-fuse device S3. Therefore, there is no need to perform through-current analysis on 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.

[0055] This embodiment will combine Figure 5 , taking the second operating condition as an example, the through current analysis of the second operating condition is performed. Figure 5 For the analysis diagram of the through-current of the second working condition, see Figure 5 , the total through-current I in the second operating condition T is the first through current I T1 , the second through current I T2 , the third through current I T3 The sum of I T = I T1 + I T2 + I T3 .

[0056] Figure 5 In the first through current I T1 The flow path of current is as follows: starting from the DC busbar of the traction substation, it flows through the grid switch K1, the grid cable, the first anchor section, the pantograph, the second anchor section, and finally flows to the current-collecting train L2;

[0057] The second through current I T2The flow path is as follows: starting from the regenerative braking train L3, it flows through the pantograph and the second anchor section, and finally flows to the flow-taking train L2;

[0058] The third through current I T3 The flow path is as follows: starting from the regenerative braking train L3, it flows through the first anchor section, the grid cable, the grid switch K1, the traction substation DC bus, the grid switch K2, the grid cable, the second anchor section, and finally flows to the current-taking train L2.

[0059] Furthermore, by performing through-current analysis on the second, third and fourth operating conditions, the second operating condition is divided into the first sub-operating condition and the second sub-operating condition, the third operating condition is divided into the third sub-operating condition and the fourth sub-operating condition, and the fourth operating condition is divided into the fifth sub-operating condition and the sixth sub-operating condition.

[0060] In this embodiment, taking the second working condition as an example, the second working condition can be further divided into a first sub-working condition and a second sub-working condition. The principle is as follows:

[0061] When there is no regenerative braking train L3, the situation at this time is the first sub-operating condition; when there is a regenerative braking train L3, a regenerative braking current I3 returned to the contact network will be generated, and the situation at this time is the second sub-operating condition.

[0062] The principles and steps for 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 the principles and steps for dividing the second working condition into the first sub-working condition and the second sub-working condition, and will not be repeated here.

[0063] Based on this, the corresponding contact network insulation anchor section joint equivalent circuit model can be established according to the working conditions. The contact network insulation anchor section joint equivalent circuit model of each working condition is shown in the figure below: Figures 6 to 11 shown.

[0064] Figure 6 The equivalent circuit model diagram of the contact network insulation anchor section joint of the first sub-operating condition, where I T is the total through current; R SS is the equivalent resistance inside the traction substation; R K1 The resistance of the Internet cable connected to the Internet switch K1; R K2 The resistance of the Internet cable connected to the Internet switch K2; R P It is the branch resistance between the pantograph and the contact network insulation anchor section joint;

[0065] R S1 is the branch resistance of the anti-fuse device S1; R S2 is the branch resistance of the anti-fuse device S2; R S3is the branch resistance of the anti-fuse device S3; for the equivalent circuit model where the anti-fuse device is not installed, or all three anti-fuse devices are not installed, the branch resistance R S1 、R S2 、R S3 Set to infinity. Figure 3 This is the wiring diagram of the anti-fuse device.

[0066] also, Figure 6 In the example, we use the general symbol R ijk Indicates the resistance of each section of the contact network. R ijk In , i and j represent the starting point and the end point of the catenary section respectively; i and j are A, B, C, D, E, F, and P, corresponding to points A, B, C, D, E, F, and P respectively, where point P is the position of the pantograph when the moving train stops; k is 1 or 2, representing the first anchor section or the second anchor section respectively. For example, Figure 6 In, R BP1 is the resistance of the first anchor segment from point B to point P.

[0067] Figures 7 to 11 The equivalent circuit model diagrams of the contact network insulation anchor section joints are respectively for the second sub-operating condition, the third sub-operating condition, the fourth sub-operating condition, the fifth sub-operating condition, and the sixth sub-operating condition, where: Figures 7 to 11 The meaning of each resistor is Figure 6 The same, no further description here.

[0068] S2: Use the equivalent circuit model of the catenary insulation anchor section joint and the anti-fuse device to determine the equivalent circuit of each working condition. Calculate the total through-current I under the working condition when the moving train stops based on 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 .

[0069] It should be noted that, in this embodiment, the total through-current is obtained by vehicle type grouping. Since different vehicle types have different values ​​of starting current, the values ​​of the total through-current generated at this time will also be different.

[0070] Preferably, the branch resistor R P It includes the contact resistance of the working branch of the pantograph and 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.

[0071] Among them, the virtual connection resistance of the non-working branch of the pantograph and the contact network insulation anchor section joint, that is, the transition resistance at the virtual connection between the pantograph and the non-working branch of the contact network insulation anchor section joint, its value can be obtained through calculation, but due to factors such as the non-fixed lifting force of the pantograph, the random parking position of the moving train, and the great influence of wind and air humidity, it is difficult to simulate the parking position of the moving train in all scenes and all positions.

[0072] Therefore, the branch resistance R between the pantograph and the contact network insulation anchor section joint when the train stops is obtained through a large amount of field measurement data in this embodiment. P The advantage of this method is that it can simulate the random parking position of a moving train, so as to better determine the loop impedance between the pantograph and the contact network insulation anchor section joint; wherein, according to the measured data, when the value range of the pantograph lifting force is 80N~120N, the branch resistance R under normal circumstances P The normal value is 0.1mΩ~100mΩ.

[0073] S3: total through current I T and 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 current that can be passed through, based on the effective current I P And the protection ratio η is calculated based on the through current.

[0074] Preferably, the contact wire fusing boundary condition is the tension on the contact wire and the temperature of the contact wire under the tension.

[0075] In this embodiment, the temperature of the contact line can be calculated through vehicle parameters. The vehicle parameters are obtained based on the load process of typical traction and braking of the train. The vehicle parameters can determine the current required for traction by the current-taking train L2 and the current size and current duration of the current inverter fed back to the contact network by the regenerative braking train L3, and then calculate the heating condition of the virtual connection part between the pantograph and the contact network insulation anchor section joint to obtain the temperature of the contact line.

[0076] Furthermore, in the contact wire fusing boundary condition, the limit value of the tension on the contact wire is set to 12 kN, and the limit value of the temperature of the contact wire under this tension is set to 150°C.

[0077] Preferably, the total through current I T and 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 current that can be passed through, based on the effective current I P The protection ratio η is calculated based on the current that can be passed through, including:

[0078] S101: Determine the branch resistance R P The numerical range of .

[0079] In this embodiment, in S101, by increasing the branch resistance R P Verification range, determine the branch resistance R P range of values, thereby minimizing the impact of extreme conditions on the system's flow capacity.

[0080] Furthermore, the branch resistance R P The numerical range is R Pmin ~R Pmax , R Pmin is the branch resistance R P The minimum value of R Pmax is the branch resistance R P The maximum value of For a fixed step size, the branch resistance R P The value range is divided, and n branch resistances R can be obtained. P The values ​​include:

[0081] R Pmax 、 、 、……、 、 、R Pmin .

[0082] Furthermore, the value of n is 20 or 30.

[0083] S102: Determine the total through current I T The numerical value of .

[0084] In this embodiment, in S102, the first through current I T1 , the second through current I T2 , the third through current I T3 The possible maximum value determines the total through-current I T The numerical value of .

[0085] Furthermore, the total through current I T The value of I Tmax ; If is the step size, for the total through current I T The maximum value is I Tmax By dividing, we can get m total through currents I T The values ​​include:

[0086] 、 、 、……、 、 , I Tmax .

[0087] Furthermore, the value of m is 20.

[0088] S103: Combined branch resistance R P The value range and 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 .

[0089] For example, in S103, the branch resistor R P The value range and 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 way is as follows:

[0090] When the total through current I T The value of I Tmax When the branch resistance R P The value of R Pmax 、 、 、……、 、 、R Pmin , use the node voltage method to calculate the branch resistance R corresponding to the above value P The effective current I P ;

[0091] When the total through current I T The value of When the branch resistance R P The value of R is also Pmax 、 、 、……、 、 、R Pmin , use the node voltage method to calculate the branch resistance R corresponding to the above value P The effective current I P ;

[0092] By analogy, the node voltage method can be used to calculate the total through-current I T The value of all branch resistances R P The effective current I P , at this time the effective current I P The number of values ​​of is , where the effective current I P The unit is A.

[0093] S104: Screening effective current I using contact line fusing boundary conditions P , and obtain the transmissible current.

[0094] In this embodiment, in S104, the effective current I is screened using the contact line fusing boundary condition. P The method of obtaining the crossable current includes: judging whether the tension and temperature of the contact line are less than the limit value of the contact line melting boundary condition; if so, screening the effective current I of the contact line at this time P As a transverse current.

[0095] Furthermore, the maximum cross-current current is the maximum cross-current current I TC , the maximum current that can pass through I TC The corresponding branch resistance R P That is the maximum traversable resistance R PC ; If the maximum passable current I TC Corresponding to multiple 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 .

[0096] S105: Based on the effective current I P and the through-current, calculate the protection ratio η.

[0097] In this embodiment, in S105, the expression of the protection ratio η is:

[0098]

[0099] Where, f is the number of values ​​of the current that can pass through, is the effective current I P The number of values ​​​​of .

[0100] S4: Select the anti-fuse device installation plan based on the protection ratio η and perform capacity verification.

[0101] Among them, the anti-fuse device installation plan is to install the anti-fuse device between the joints of the two sections of the contact network insulation anchor sections; the capacity verification is to evaluate and verify the transportation capacity of the contact network to determine whether it can meet the expected transportation needs.

[0102] Specifically, the anti-fuse device installation scheme is shown in Table 1. In Table 1, "×" indicates that the anti-fuse device is not installed, and "√" indicates that the anti-fuse device is installed. For example, Scheme 3 indicates that the anti-fuse device S1 is not installed, the anti-fuse device S2 is installed, and the anti-fuse device S3 is not installed; Scheme 5 indicates that the anti-fuse device S1 is installed, the anti-fuse device S2 is installed, and the anti-fuse device S3 is not installed.

[0103] In Table 1, further, Scheme 1 is used to compare the anti-fuse effects of other installation schemes.

[0104] Table 1. Installation scheme of anti-fuse device for contact network insulation anchor section joint

[0105]

[0106] Preferably, 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.

[0107] When the protection ratio η is greater than 95%, the selected fuse installation scheme can effectively ensure safe and reliable operation of the catenary when the train stops within the insulated anchor joint. If the protection ratio η is greater than 95% and other parameters or conditions are the same and multiple fuse installation schemes are available, the fuse installation scheme that combines high cost-effectiveness and high protection rate can be selected.

[0108] In addition, if the value of the protection ratio η is very low, you can consider increasing the current carrying capacity of the contactor corresponding to the branch resistance of the device, for example, selecting a rated current carrying capacity I N Larger contactors; at the same time, reduce the branch resistance of the anti-fuse device, for example by increasing the cable cross-sectional area.

[0109] Preferably, 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, the branch resistance R S1 , device branch resistance R S2 , device branch resistance R S3 The rated current carrying capacity of the corresponding contactor is I N =2000A.

[0110] In this embodiment, the rated current carrying capacity of the contactor corresponding to the branch resistance of each device is set to I N =2000A reasons include:

[0111] According to the calculation of actual projects, the short-term maximum current of a running train, that is, the maximum current at the start of a running train is generally within 4000A. The rated current capacity I N =2000A can fully meet the various flow capacities required by the anti-fuse device installation solution selected in this embodiment.

[0112] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance.

[0113] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the above-described embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily conceive of changes to the technical solutions described in the above-described embodiments within the technical scope disclosed by the present invention, or replace some of the technical features therein with equivalents. Such modifications, changes, or replacements do not deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A method for preventing fuse-breaking of contact network 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 a through-current exists at the contact network insulation anchor section joint, operating conditions are divided according to different positions of the contact network insulation anchor section joint at which 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 operating conditions; The operating conditions are divided into the first operating condition, the second operating condition, the third operating condition, the fourth operating condition and the fifth operating condition according to the different positions of the moving train stopping at the contact network insulation anchor section joint; 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; When dividing each of the operating conditions into sub-operating conditions, determining whether there is a regenerative braking train; if there is no regenerative braking train, dividing the second operating condition into the first sub-operating condition, dividing the third operating condition into the third sub-operating condition, and dividing the fourth operating condition into the fifth sub-operating condition; if there is a regenerative braking train L3, dividing the second operating condition into the second sub-operating condition, dividing the third operating condition into the fourth sub-operating condition, and dividing the fourth operating condition into the sixth sub-operating condition; The equivalent circuit model of the catenary 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 moving train stops is calculated based on 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 line fusing boundary condition to screen the effective current I P As the cross-current, based on the effective current I P and the protection ratio η calculated based on the cross-current; The total through current I T and the branch resistance R P Calculate the effective current I P , using the contact line fusing boundary condition to screen the effective current I P As the traversable current, based on the effective current I P and the cross-current to calculate the protection ratio η, comprising: Determine the branch resistance R P The numerical range of The branch resistance R P The numerical range is R Pmin ~R Pmax , R Pmin is the branch resistance R P The minimum value of R Pmax is the branch resistance R P The maximum value of For a fixed step size, the branch resistance R P The value range of the branch resistance R can be divided into n P The values ​​include: R Pmax 、 、 、……、 、 、R Pmin； Determine the total through current I T The value of Through the first through current I T1 , the second through current I T2 , the third through current I T3 The possible maximum value determines the total through-current I T The value of The total through current I T The value of I Tmax ; If is the step size, for the total through current I T The maximum value is I Tmax Dividing it into m, we can get the total through current I T The values ​​include: 、 、 、……、 、 、I Tmax； Combined with the branch resistor R P The numerical 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, calculating the protection ratio η; The expression of the protection ratio η is: ； Where, f is the number of values ​​of the current that can pass through, is the effective current I P The number of values ​​of ; Based on the protection ratio η, an anti-fuse device installation plan is selected and a capacity check is performed.

2. A method for protecting the contact network from fuse-breaking of a DC traction power supply system according to claim 1, 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.

3. 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 branch resistance R P It includes the contact resistance between the pantograph and the working branch of the contact network insulation anchor section joint, the virtual connection resistance between 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.

4. 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 contact wire fusing boundary condition is the tension on the contact wire and the temperature of the contact wire under the tension.

5. A method for protecting the contact network from fuse-breaking of a DC traction power supply system according to claim 4, 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.

6. 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 maximum cross-current I TC , the maximum passable current I TC The corresponding branch resistance R P That is the maximum traversable resistance R PC If the maximum current that can pass 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 .

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