A phase-controlled closing method and heavy haul locomotive circuit breaker

Abstract

The present application relates to the technical field of electrified railway control, and discloses a phase control closing method and a heavy haul locomotive circuit breaker, the method comprising: step one, establishing equivalent mathematical models for the heavy haul locomotive, traction substation, AT substation and traction network; step two, establishing a vehicle-network-station simulation model based on a MATALB / Simulink simulation platform; step three, obtaining the influence of different line loads on phase selection closing according to the vehicle-network-station simulation model; and step four, determining a phase control closing scheme and conducting test verification. The phase control closing and opening method of the heavy haul locomotive circuit breaker with the above structure can establish equivalent mathematical models for the heavy haul locomotive, traction substation, AT substation and traction network, and then establish a vehicle-network-station simulation model, analyze the influence of different line loads on phase selection closing, and determine a phase selection closing scheme according to the breakdown characteristics of the circuit breaker and the analysis results. The phase selection closing scheme determined through test verification can achieve the purpose of reducing the overvoltage of the closing system.

Description

Technical Field

[0001] This invention relates to the field of electrified railway control technology, and in particular to a phase-controlled closing method and a circuit breaker for heavy-duty locomotives. Background Technology

[0002] The main circuit breaker of a heavy-duty locomotive is the main switch used to connect and disconnect the power supply to electric locomotives and electric multiple units (EMUs). In the event of a short circuit, grounding, or other fault in the main circuit, the main circuit breaker can quickly disconnect, providing protection. Main circuit breakers are generally air circuit breakers, consisting of an arc-extinguishing chamber, a disconnecting switch, a control mechanism, and a compressed air supply system. When disconnecting, compressed air enters the arc-extinguishing chamber, first breaking the active contacts and extinguishing the arc. Then, the compressed air causes the disconnecting switch to open; this opening occurs in a de-energized state. The active contacts then reset, preparing for the next closure of the main circuit breaker. When the main circuit breaker closes, compressed air causes the disconnecting switch to close; this closing occurs in an energized state.

[0003] As a crucial component of the high-voltage system of an electric locomotive, the main circuit breaker is used to switch the operating current of the traction unit and to safely disconnect the train's high-voltage transformers and overhead contact lines in the event of severe interference. The main circuit breaker is the source of power assurance; its performance directly affects the power quality of all electronic equipment in the electric locomotive, thus directly impacting the safe operation of the entire locomotive and the lifespan of its electrical equipment.

[0004] Currently, the closing of circuit breakers on heavy-haul locomotives is random. Frequent opening and closing of the main circuit breaker causes the high-voltage system to undergo transitions between different electromagnetic states. Energy constantly changes between inductive and capacitive components, leading to operational overvoltages in the heavy-haul locomotive operating system. The arc discharge accompanying these overvoltages can burn the pantograph and other contact network components, causing traction substations to trip, further resulting in partial power outages and locomotive shutdowns. Simultaneously, the powerful short-circuit current generates electrodynamic and thermal effects that severely damage traction transformers, feeder circuit breakers, and other equipment, threatening the stable operation of the traction power supply system. The overvoltage generated by the on-board circuit breaker closing not only impacts the contact network and causes traction substation trips but also deteriorates the electromagnetic environment of the heavy-haul locomotive, damaging equipment insulation and, in severe cases, affecting the safe operation of the locomotive.

[0005] Therefore, how to suppress closing overvoltage has become an urgent technical problem to be solved. Summary of the Invention

[0006] The present invention aims to provide a phase-controlled closing method for circuit breakers of heavy-duty locomotives, solving the technical problem of operational overvoltage caused by random closing of circuit breakers in heavy-duty locomotives in the prior art.

[0007] The above-mentioned objectives are mainly achieved through the following technical solutions:

[0008] Firstly, a phase-controlled closing method includes: establishing equivalent mathematical models of heavy-duty locomotives, traction networks, traction substations, and AT substations; establishing an overvoltage simulation model based on the equivalent mathematical models of heavy-duty locomotives, traction networks, traction substations, and AT substations; simulating various operating conditions of heavy-duty locomotives using the overvoltage simulation model to obtain the influence of load under different operating conditions on the phase-selective closing of circuit breakers; and determining the phase-controlled closing scheme of circuit breakers based on the influence of load under different operating conditions on the phase-selective closing of circuit breakers and the pre-breakdown characteristics of circuit breakers.

[0009] Compared to existing technologies, the advantages of this invention are as follows: By establishing equivalent mathematical models of heavy-haul locomotives, traction substations, AT substations, and the traction network, and combining actual parameters and a simulation platform, a simulation model integrating the vehicle, network, and substation is established. This model is then used to analyze the impact of different line loads on the phase selection and closing of circuit breakers, as well as the variation of overvoltage generated during closing with different line loads. Furthermore, by combining the pre-breakdown characteristics of circuit breaker closing, the phase angle scheme for circuit breaker closing is determined. Finally, analysis can be conducted through phase-controlled closing tests to obtain specific closing phase angle parameters. This effectively suppresses overvoltage and prevents circuit breaker breakdown during closing, thus improving the safety of electrified railway control technology and solving the technical problem of operational overvoltage caused by random closing of circuit breakers in existing technologies for heavy-haul locomotives.

[0010] Secondly, a phase-controlled closing device for a heavy-duty locomotive circuit breaker includes: a mathematical model construction module for establishing equivalent mathematical models of the heavy-duty locomotive, traction network, traction substation, and AT substation; a simulation model construction module for establishing an overvoltage simulation model based on the equivalent mathematical models of the heavy-duty locomotive, traction network, traction substation, and AT substation; a simulation module for simulating various operating conditions of the heavy-duty locomotive using the overvoltage simulation model to obtain the influence of load under different operating conditions on the phase-selective closing of the circuit breaker; and a closing phase-controlled module for determining the phase-controlled closing scheme of the circuit breaker based on the influence of load under different operating conditions on the phase-selective closing of the circuit breaker and the pre-breakdown characteristics of the circuit breaker.

[0011] Thirdly, a heavy-duty locomotive circuit breaker includes an arc-extinguishing chamber, a disconnecting switch, a control and operating mechanism, and a compressed air supply system, as well as a phase selection controller that performs a phase-controlled closing method as described in the first aspect; the phase selection controller is connected to the control and operating mechanism and is used to send a closing command to the control and operating mechanism so that the control and operating mechanism performs a closing operation based on the closing command.

[0012] Fourthly, an electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the steps of a phase-controlled closing method as described in the first aspect.

[0013] Fifthly, a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of a phase-controlled closing method as described in the first aspect.

[0014] Sixthly, a computer program product includes a computer program that, when executed by a processor, implements the steps of a phase-controlled closing method as described in the first aspect. Attached Figure Description

[0015] Figure 1 This is a schematic flowchart of a phase-controlled closing method according to an embodiment of the present invention;

[0016] Figure 2 This is a schematic diagram of the voltage transformer winding circuit structure in an embodiment of the present invention;

[0017] Figure 3 This is a schematic diagram of the winding circuit structure of the first traction transformer in an embodiment of the present invention;

[0018] Figure 4 This is a schematic diagram of the four-quadrant rectifier circuit structure in an embodiment of the present invention;

[0019] Figure 5 This is a schematic diagram of the second traction transformer winding circuit structure in an embodiment of the present invention;

[0020] Figure 6 This is a schematic diagram of the autotransformer winding circuit structure in an embodiment of the present invention;

[0021] Figure 7 This is a schematic diagram of a simulation model of a traction substation in an embodiment of the present invention;

[0022] Figure 8 This is a schematic diagram of the contact suspension of the AT double-track traction net in an embodiment of the present invention;

[0023] Figure 9 This is a schematic diagram of the traction network simulation model in an embodiment of the present invention;

[0024] Figure 10 This is a schematic diagram of a heavy-duty locomotive simulation model in an embodiment of the present invention;

[0025] Figure 11 This is a schematic diagram of the AT simulation model in the embodiments of the present invention;

[0026] Figure 12This is a schematic diagram of the overvoltage simulation model in an embodiment of the present invention;

[0027] Figure 13 This is a timing diagram of the circuit breaker closing process in an embodiment of the present invention;

[0028] Figure 14 This is a diagram showing the relationship between different closing phase angles and pre-breakdown time in an embodiment of the present invention;

[0029] Figure 15 This is a diagram showing the relationship between different closing phase angles and pre-breakdown voltage in an embodiment of the present invention;

[0030] Figure 16 This is a schematic diagram of the structure of a phase-controlled closing device according to an embodiment of the present invention;

[0031] Figure 17 This is a schematic diagram of the structure of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0032] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0033] One embodiment of the present invention provides a phase-controlled closing method for a circuit breaker in a heavy-duty locomotive, such as... Figure 1 As shown, it includes the following steps:

[0034] Step 1: Establish equivalent mathematical models of heavy-duty locomotives, traction networks, traction substations, and AT stations.

[0035] Based on the actual situation of the electrified railway system, equivalent model replacements were performed on heavy-haul locomotives, traction networks, traction substations, and AT substations, respectively. Equivalent mathematical models of heavy-haul locomotives, traction networks, traction substations, and AT substations were established, laying the foundation for the subsequent construction of overvoltage simulation models.

[0036] In a preferred embodiment, the equivalent mathematical model of the heavy-duty locomotive includes: a roof-mounted high-voltage cable transmission line model constructed using a π-type lumped parameter model, a voltage transformer winding circuit constructed using a saturable transformer model, a traction transformer winding circuit constructed using a multi-winding transformer, and a four-quadrant converter circuit constructed using a single-phase two-level topology. The roof-mounted high-voltage cable transmission line model is used to transmit electrical energy.

[0037] It should be noted that the equivalent model replacement for heavy-duty locomotives mainly includes three parts: the roof high-voltage system, the traction transformer, and the traction converter.

[0038] The rooftop high-voltage system includes rooftop high-voltage cables and voltage transformers. The rooftop high-voltage cables play a crucial role in transmitting electrical energy, and a π-type lumped parameter model is used to construct the model of the rooftop cables.

[0039] The voltage transformer is directly connected to the pantograph and is used to measure and monitor the contact network voltage. It provides traction control or power outage protection for heavy-load locomotives when the contact network voltage fluctuates; therefore, its capacity is relatively small. The primary winding of the voltage transformer is connected to the contact network with a rated voltage of 27.5kV, while the secondary winding typically has a rated voltage of 100V. The windings and core must be reliably grounded, and short circuits are not permitted. Due to the frequent opening and closing of phase-by-phase circuit breakers by heavy-load locomotives, resonance may occur between the contact network and the voltage transformer, accompanied by a certain amount of resonant overvoltage. Therefore, a saturable transformer model is selected when designing the voltage transformer model. Specifically, the equivalent mathematical model of the voltage transformer can be implemented through a voltage transformer winding circuit.

[0040] In a preferred embodiment, such as Figure 2 As shown, the voltage transformer winding circuit includes: a first resistor R1, a first inductor jX1, a second resistor R2, a second inductor jX2, a third resistor R3, a third inductor jX3, and an iron core winding transformer; the first resistor R1 is connected in series with the first inductor jX1, and the first inductor jX1 is connected in parallel with the third resistor R3; the second resistor R2 is connected in series with the second inductor jX2, and the secondary side of the iron core winding transformer is connected in parallel with the second resistor R2; the third resistor R3 is connected in parallel with the third inductor jX3, and the third inductor jX3 is connected in parallel with the primary side of the iron core winding transformer.

[0041] As shown in the figure, R1+jX1 represents the equivalent impedance of the primary side of the iron core winding transformer, R2+jX2 represents the equivalent impedance of the secondary side of the iron core winding transformer, R3 represents the equivalent resistance of the iron core loss, and jX3 represents the reactance of the main magnetic flux.

[0042] Traction transformers are crucial for converting electrical energy into mechanical energy. Their primary function is to provide power for heavy-haul locomotive traction. Each heavy-haul locomotive train contains two traction transformers, each equipped with two traction converters. These converters require the traction transformers to store energy and also to feed the electrical energy from the traction motors back to the power grid when the locomotives undergo regenerative braking. As the operating conditions of the heavy-haul locomotives change, the voltage of the traction transformer also fluctuates continuously, and may even experience significant shocks. Traction transformers are multi-winding transformers, and their equivalent mathematical model can be implemented using a single traction transformer winding circuit.

[0043] In a preferred embodiment, such as Figure 3 As shown, the winding circuit of the first traction transformer includes: a fourth resistor R4, a fourth inductor jX4, a fifth resistor R5, a fifth inductor jX5, a sixth resistor R6, a sixth inductor jX6, a seventh resistor R7, a seventh inductor jX7, and a three-winding transformer with an iron core; the fourth resistor R4 and the fourth inductor jX4 are connected in series, and the fourth inductor jX4 and the seventh resistor R7 are connected in parallel; the fifth resistor R5 and the fifth inductor jX5 are connected in series, and the secondary side of the three-winding transformer with the fifth resistor R5 is connected in parallel; the sixth resistor R6 and the sixth inductor jX6 are connected in series, and the tertiary side of the three-winding transformer with the sixth resistor R6 is connected in parallel; the seventh resistor R7 and the seventh inductor jX7 are connected in parallel, and the seventh inductor jX7 is connected in parallel with the primary side of the three-winding transformer with the iron core.

[0044] The traction converter receives 27.5kV AC voltage from the overhead contact line via the main transformer. After rectification by the four-quadrant converter, a DC voltage is obtained, which is then inverted into three-phase AC to drive the traction motor. The intermediate DC link acts as a voltage stabilizer. The four-quadrant rectifier, as the core interface device for power transmission and conversion between the traction network and the heavy-haul locomotive, is a crucial part of the vehicle-network coupling system. When studying vehicle-network coupling problems, the converter inside the locomotive is often simplified. The inverter and motor sections, as loads of the four-quadrant converter and located on the DC side, are usually equivalent to a resistive circuit for analysis. As the grid-side converter for the heavy-haul locomotive, the four-quadrant converter operates in two modes: in traction mode, it operates as a rectifier, absorbing power from the traction network; in regenerative braking mode, it operates as an inverter, feeding energy from the traction motor back to the traction network. Therefore, the equivalent mathematical model of the traction converter can be implemented using a single-phase, two-level topology four-quadrant rectifier circuit.

[0045] In a preferred embodiment, such as Figure 4 As shown, the four-quadrant rectifier circuit includes: an oscilloscope u s Eighth inductor L s Eighth resistor R s First bipolar transistor T1, second bipolar transistor T2, third bipolar transistor T3, fourth bipolar transistor T4, first capacitor C d and the ninth resistor R d One end of the oscilloscope is connected to the eighth inductor L. s The first terminal is connected to the eighth inductor L. s The second and eighth resistors R s The first end is connected to the eighth resistor R. s The second terminal is connected to the emitter terminal of the first bipolar transistor, and the oscilloscope u sThe other end is connected to the emitter of the third bipolar transistor T3; the emitter of the first bipolar transistor T1 is connected to the collector of the second bipolar transistor T2, and the emitter of the third bipolar transistor T3 is connected to the collector of the fourth bipolar transistor T4; the collector of the first bipolar transistor T1 is connected to the collector of the third bipolar transistor T3, and the emitter of the second bipolar transistor T2 is connected to the emitter of the fourth bipolar transistor T4; the collector of the third bipolar transistor T3 is connected to the first capacitor C. d The first terminal is connected to the emitter terminal of the fourth bipolar transistor T4 and the first capacitor C. d The second terminal is connected; the first capacitor C d The first terminal is connected to the ninth resistor R d The first terminal is connected to the first capacitor C. d The second terminal is connected to the ninth resistor R d The second end is connected.

[0046] In a preferred embodiment, the equivalent mathematical model of the traction network includes a multi-conductor transmission line model, the electrical parameters of which include series impedance and parallel admittance.

[0047] The traction network refers to the uplink and downlink power supply system consisting of the overhead contact line, rails, feeders, and return lines. The traction network is composed of multiple parallel conductors, "divided" into different uniform segments by longitudinally connected parallel elements; therefore, it is considered a multi-conductor transmission line model when establishing the traction network model. The electrical parameters of the traction network are fundamental parameters of electrified railways, including series impedance and parallel admittance.

[0048] In a preferred embodiment, the impedance parameters include the self-impedance of the conductor and the mutual impedance between the two conductors; according to Carson's theory, the self-impedance Z of the i-th conductor is... ii The calculation formula is:

[0049]

[0050] The mutual impedance Z between the i-th and j-th conductors ij The calculation formula is:

[0051]

[0052] Where r1 is the effective resistance per unit length of the conductor (Ω / km), and r2 is the earth's own resistance (π). 2 f10 -4 Ω / km), μ0 is the free permeability (4π¹⁰) -4 H / km), f is the current frequency (Hz), D g Equivalent depth of conductor and ground loop R ε1Let d be the equivalent radius of the conductor (m), d be the vertical distance between the two conductors (m), and ρ be the soil resistivity (Ω×m).

[0053] In a preferred embodiment, the calculation of admittance parameters (the self-potential coefficient of the conductor and the mutual potential coefficient between the two conductors) is first performed by listing the potential coefficient matrix based on the geometric dimensions and spatial location of the conductors. The inverse of the potential coefficient matrix is ​​the conductor distributed capacitance coefficient matrix. According to electromagnetic field theory, the line capacitance is calculated based on the electrostatic field. In a multi-conductor transmission line system, the voltage U to ground of each conductor and the line charge density Q have the following relationship:

[0054]

[0055] The simplified formula relating the voltage U of each conductor to ground to the linear charge density Q is as follows:

[0056] U = PQ; and Q = CU; then the conductor distributed capacitance coefficient matrix is ​​obtained: C = P -1 .

[0057] P is the potential coefficient matrix, and C is the capacitance coefficient matrix. Both P and C are symmetric matrices.

[0058] In a semi-infinite planar geodetic model, the self-potential coefficient and mutual potential coefficient can be calculated using the electrostatic field mirror method. For example, if there are two conductors i and j in space, then the self-potential coefficient P of the i-th conductor... ii The calculation formula is:

[0059]

[0060] The mutual potential coefficient P between the i-th and j-th conductors ij The calculation formula is:

[0061]

[0062] Where ε0 is the dielectric constant of air. D ij Let d be the mirror distance between the i-th wire and the j-th wire. ij Let r be the spatial distance between the i-th and j-th wires. i h is the equivalent radius of the i-th wire. i Let be the height of the i-th wire above the ground.

[0063] In a preferred embodiment, the equivalent mathematical model of the traction substation includes: the traction transformer winding circuit, which adopts the Scott connection method or the V / X connection method.

[0064] The traction transformer is the core component of the traction substation. There are many ways to connect it. Among them, the V / X connection and Scott connection are the main ones used in AT power supply. The traction transformer designed in this invention adopts the Scott connection method.

[0065] In a preferred embodiment, the Scott connection traction transformer consists of two single-phase transformers connected together, as shown in the specific circuit diagram below. Figure 5 As shown, the second traction transformer winding circuit includes a first single-phase transformer and a second single-phase transformer; the primary winding of the first single-phase transformer is led out at both ends, the first end of the primary winding is connected to phase A of the power system, and the second end of the primary winding is connected to phase B of the power system, denoted as transformer M; the primary winding of the second single-phase transformer is led out at one end, the lead-out end of the primary winding is connected to phase C of the power system, and the lead-out end of the non-primary winding is connected to the midpoint D of the primary winding of the first single-phase transformer, denoted as transformer T.

[0066] Depend on Figure 5 It can be seen that:

[0067]

[0068] K1 is the turns ratio of the transformer at location M, and K2 is the turns ratio of the transformer at location T. Based on the vector diagram drawn from the circuit diagram, we can obtain:

[0069]

[0070] The secondary output voltages are equal in magnitude but 90 degrees out of phase. Therefore:

[0071]

[0072] When a 220kV line voltage is connected to the primary side, let K1 = 4. The output voltage is then 55kV.

[0073] In a preferred embodiment, when the traction network uses AT power supply, an autotransformer (AT) is installed approximately every 10 km along the railway line; this location is called an AT station. The autotransformer bridges the contact wire, positive feeder, and rails of the traction network, supporting a 2*27.5kV power supply system. Therefore, the equivalent mathematical model of the AT station uses the autotransformer winding circuit, with the secondary winding of the autotransformer sharing a portion of the primary winding.

[0074] In a preferred embodiment, such as Figure 6 As shown, the autotransformer winding circuit includes: a ninth inductor N1, a tenth inductor N2, and a tenth resistor Z; the ninth inductor N1 and the tenth inductor N2 are connected in series, and the tenth inductor N2 and the tenth resistor Z are connected in parallel.

[0075] Depend on Figure 6 It can be seen that the turns ratio of the autotransformer is k = U 1n / U 2n = (N1+N2) / N2=2, that is, N1=N2. Since N1I1=N2I2, then I1=I2. Z =I1+I2=2I1, and thus U1=U2.

[0076] Step 2: Based on the equivalent mathematical models of heavy-duty locomotives, traction networks, traction substations, and AT stations, establish an overvoltage simulation model.

[0077] This invention employs the MATLAB / Simulink simulation platform to construct simulation models for heavy-haul locomotives, traction networks, traction substations, and AT substations, thereby establishing an overvoltage simulation model to output overvoltage simulation waveforms. The equivalent mathematical models of the heavy-haul locomotive, traction network, traction substation, and AT substation are converted into corresponding simulation models, and simulation parameters are set. Following the actual wiring principles of electrified railways, the simulation models of the heavy-haul locomotive, traction substation, and AT substation are connected to the traction network simulation model to construct the overvoltage simulation model.

[0078] Specifically, as shown in step 1 above, the secondary output voltages of the Scott-connected traction transformer have a 90-degree phase difference, are decoupled from each other, and are independent, exhibiting good balance characteristics. In this traction transformer simulation model, the transformer capacity is set to 75MVA, and the simulation model is as follows: Figure 7 As shown.

[0079] The equivalent model of each power supply section in the traction network can be equivalently replaced by a series impedance matrix and a parallel admittance matrix. The series impedance matrix includes the self-resistance and self-inductance of the conductors, as well as the mutual resistance and mutual inductance between the conductors. The parallel admittance matrix includes the capacitance between the conductors and ground, the capacitance between the conductors, and the leakage resistance of the rails.

[0080] The calculation method of the matrix is ​​given in the process of establishing the mathematical model of the traction network. However, there are many transmission lines in the traction network, and the calculated impedance matrix and admittance matrix have many elements, which are too large. The established traction network model is very complex. Therefore, it is necessary to simplify the established model by equivalent means.

[0081] The principle is to replace all conductors at the same voltage level with a single conductor of equivalent voltage. For example... Figure 8 As shown, there are a total of 10 transmission lines (ignoring the through ground wire), including up and down catenary wires, up and down contact wires, up and down rails, up and down positive feeders, and up and down protection wires. By merging and reducing the order of the matrices, the 10-conductor model can be simplified into a five-wire model of 2T-R-2F, i.e.:

[0082] 2T—Upward and downward contact network; generally composed of upward and downward catenary wires and contact wires that are equivalently combined.

[0083] R—rail; combining the up and down rails into one rail.

[0084] 2F—Uplink / Downlink feeder; in AT lines, it refers to the positive feeder.

[0085] The simplification of the model essentially involves an equivalent reduction in the order of the impedance and admittance matrices. Taking the impedance matrix as an example, let's assume the original matrix is:

[0086]

[0087] The matrix after the equivalent order reduction is:

[0088]

[0089] in:

[0090]

[0091]

[0092] Using the above formulas, a 10th-order matrix can be simplified to a 5th-order matrix, resulting in a simplified model. Similarly, for the admittance matrix, the potential coefficient matrix P can be equivalently reduced in order to obtain a 5-dimensional matrix, which can then be obtained using the formula C = P. -1 The capacitance matrix C can be derived.

[0093] Therefore, the simulation parameters are set based on the calculated impedance matrix and admittance matrix, and the simulation model is as follows: Figure 9 As shown.

[0094] Based on the mathematical model of the heavy-haul locomotive, simulation models were built for the roof-mounted high-voltage cable, high-voltage transformer, traction main transformer, and traction converter, and an on-board circuit breaker module was added. The heavy-haul locomotive simulation model is as follows: Figure 10 As shown.

[0095] Autotransformer (AT) depots are typically located along railway lines, approximately every 10 km. Each depot contains two autotransformers, connected to the up and down lines respectively. Simultaneously, the rail current is absorbed by the autotransformers and fed to the feeders, thus reducing the impact on surrounding low-voltage systems. The simulation model of the autotransformer uses a single-phase, two-winding transformer. Based on its working principle, the opposite ends of the primary and secondary windings of the single-phase transformer are connected as a common terminal to the rail. The other end of the primary winding is connected to the contact wire, and the other end of the secondary winding is connected to the positive feeder. The simulation model is as follows: Figure 11 As shown.

[0096] The closing of the on-board circuit breaker for a heavy-haul locomotive over a phase occurs during the process of the locomotive leaving the neutral section and entering another power supply arm. To make the simulation process close to reality, the simulation model of the heavy-haul locomotive is connected to the end of the traction network power supply arm. Then, according to the actual wiring method of electrified railways, the traction substation and AT substation are connected to the traction network to form a complete car-network-substation simulation model (i.e., the above-mentioned overvoltage simulation model), as follows. Figure 12 As shown.

[0097] Step 3: Use the overvoltage simulation model to simulate various operating conditions of the heavy-load locomotive to obtain the influence of load on the phase selection and closing of the circuit breaker under different operating conditions.

[0098] During normal operation of electrified railways, multiple heavy-load locomotives often operate on a single power supply arm. Each running heavy-load locomotive is equivalent to a single-phase high-current load. With multiple locomotives in operation, the line load constantly changes, which has a certain impact on the circuit breaker closing overvoltage. First, a simulation analysis of single-locomotive operation is conducted to explore the influence of the on-board circuit breaker closing time on the closing overvoltage. Then, based on actual test data, the relationship between the speed and impedance of the heavy-load locomotive is analyzed. Next, based on this relationship, the operation of multiple locomotives is analyzed, simulating the impact of the heavy-load locomotive load on the closing overvoltage when traveling on the same line and adjacent lines. The effects of load impedance, heavy-load locomotive speed, and load distance on the phase selection for closing are then determined.

[0099] (1) Single vehicle load analysis

[0100] During the phase transition of a heavy-haul locomotive, the opening and closing of the circuit breaker exhibits significant randomness. The overvoltage generated by this random closing not only impacts the overhead contact line but also affects the internal circuitry of the locomotive. Random closing refers to the randomness of the closing phase, which is reflected in the simulation as the random variation of the circuit breaker's closing time. Therefore, for a single-vehicle load, a vehicle-network-substation simulation model built using MATLAB / Simulink is employed to study the variation of closing overvoltage with closing time.

[0101] (2) Multi-vehicle load analysis

[0102] Based on the actual test data of single-vehicle load analysis, the relationship between the speed and impedance of heavy-duty locomotives was analyzed, and the speed and impedance of heavy-duty locomotives are roughly linear.

[0103] This refers to a situation where a heavy-load locomotive enters the end of a power supply arm after passing through an electrical phase divider, and a normally operating heavy-load locomotive is already on that arm. When the circuit breaker of the heavy-load locomotive at the end of the power supply arm performs a closing operation, the closing overvoltage generated by the heavy-load locomotive running on the power supply arm will have a certain impact. To address this actual operating situation, a simulation model is established based on the vehicle-network-station simulation model. Based on the relationship between the speed and impedance of the heavy-load locomotive, an equivalent substitution is made for the heavy-load locomotive running on the power supply arm. According to the actual operating conditions of the heavy-load locomotive, a suitable speed is selected to obtain the impedance at the corresponding speed, which is then used to replace the simulation model of the heavy-load locomotive operating at that speed. Based on the above simulation model, the effects of the load impedance angle and the speed of the heavy-load locomotive on the closing overvoltage are investigated, and the changes in the closing overvoltage when the distance between the two vehicles changes are analyzed. The closing overvoltage generated when there is a car on the line is greater than when there is no car. When other heavy-load locomotives are running on the line, the greater the load distance, that is, the farther the distance between the two cars, the smaller the closing overvoltage. In other words, the farther the distance, the smaller the impact on the closing overvoltage.

[0104] "Train operation on adjacent lines" refers to two heavy-load locomotives operating on the same section's up and down power supply arms, respectively. Based on the actual operating conditions, a simulation model was established using a vehicle-network-station simulation model to investigate the effects of load impedance angle and heavy-load locomotive speed on closing overvoltage when trains are operating on adjacent lines. The changes in closing overvoltage as the distance between the two locomotives changed were also analyzed. The results show that changes in load impedance angle, locomotive speed, and load distance on adjacent lines have relatively small effects on closing overvoltage.

[0105] In a preferred embodiment, the first overvoltage is greater than the second overvoltage, wherein the first overvoltage is the overvoltage generated by the load of the heavy-haul locomotive traveling on the same line closing the circuit breaker, and the second overvoltage is the overvoltage generated by the load of the heavy-haul locomotive traveling on an adjacent line closing the circuit breaker; the third overvoltage is greater than the fourth overvoltage, wherein the third overvoltage is the overvoltage generated by the first load of the heavy-haul locomotive traveling on the same line closing the circuit breaker, and the fourth overvoltage is the overvoltage generated by the second load of the heavy-haul locomotive traveling on the same line closing the circuit breaker, wherein the first load impedance is greater than the second load impedance, or the first load distance from the first load to the heavy-haul locomotive is less than the second load distance from the second load to the heavy-haul locomotive; the fifth overvoltage is greater than the sixth overvoltage, wherein the fifth overvoltage is the overvoltage generated by the heavy-haul locomotive traveling at a first speed closing the circuit breaker, and the sixth overvoltage is the overvoltage generated by the heavy-haul locomotive traveling at a second speed closing the circuit breaker, wherein the first speed is greater than the second speed.

[0106] Step 4: Determine the phase-controlled closing scheme of the circuit breaker based on the influence of load on phase selection and closing of the circuit breaker under different operating conditions and the pre-breakdown characteristics of the circuit breaker.

[0107] The circuit breaker for heavy-duty locomotives was selected, and the breakdown characteristics of the circuit breaker were analyzed based on the pre-breakdown characteristics of the permanent magnet circuit breaker. Based on the analysis results, the phase-controlled closing scheme was determined, and phase-controlled closing test analysis was conducted.

[0108] (1) Selection of circuit breakers for heavy-duty locomotives

[0109] As a key component of heavy-duty locomotives, on-board circuit breakers play a crucial role in connecting the train and the power grid and transmitting electrical energy. Traditional circuit breakers operate randomly, and the uncertainty of the closing phase can cause overvoltages of varying degrees. This not only impacts the traction power supply system but also damages equipment. To address the problem of suppressing closing overvoltages, starting with the circuit breaker itself, synchronous closing technology can effectively reduce overvoltages. Since traditional circuit breakers are not suitable for synchronous closing technology, optimized circuit breaker selection is necessary. A suitable circuit breaker model can be well-matched to synchronous closing technology to achieve the goal of reducing overvoltages.

[0110] Currently, all circuit breakers used in electrified railways are vacuum circuit breakers. Traditional operating mechanisms for vacuum circuit breakers often employ spring-operated mechanisms. However, spring-operated mechanisms have significant limitations due to their numerous components and complex transmission relationships, failing to adapt to the miniaturization and intelligentization trends of high-voltage switchgear and not meeting the requirements of maintenance-free and low-maintenance requirements for electrified railway equipment. With the successful development of the first vacuum circuit breaker equipped with a permanent magnet mechanism, a new type of operating mechanism—the permanent magnet mechanism—has gradually come into focus. The permanent magnet mechanism is a new type of electromagnetic operating mechanism that uses permanent magnets to achieve opening and closing. Based on how the mechanism maintains its final position, permanent magnet operating mechanisms can be divided into bistable and monostable types. The characteristic of a bistable permanent magnet mechanism is that it uses permanent magnets to hold the vacuum circuit breaker at its extreme open and closed positions. Bistable means that the moving iron core can maintain its position at the end of its stroke without any external energy or latching.

[0111] By combining a bistable permanent magnet mechanism with a vacuum circuit breaker, the opening and closing phases of the vacuum circuit breaker can be precisely controlled, effectively reducing overvoltage and overcurrent generated during the opening and closing process. Therefore, to achieve fast and accurate operation, heavy-duty locomotive on-board vacuum circuit breakers can be paired with a bistable permanent magnet mechanism.

[0112] (2) Pre-breakdown characteristics of permanent magnet circuit breakers

[0113] The breakdown physical process of a vacuum gap involves the diffusion of charged particles or charged microparticles under the influence of an electric field. Therefore, a pre-breakdown process exists in the vacuum gap. When a voltage is applied across the vacuum electrode gap, a small pre-breakdown current appears between the electrodes as the voltage increases, accompanied by gas release or luminescence on the electrode surface. If the voltage across the vacuum gap is further increased, a sudden spark discharge occurs, leading to complete breakdown of the vacuum gap. This is the pre-breakdown process. During this process, the current within the vacuum gap increases instantaneously, reaching hundreds or even thousands of amperes. This can cause severe erosion of the circuit breaker's arc contacts, damaging the insulation performance of the circuit breaker and adjacent equipment, and reducing the mechanical life of the switch.

[0114] To investigate the impact of the circuit breaker's closing operation characteristics on phase control parameters, experiments were conducted on the pre-breakdown characteristics of the vacuum circuit breaker. The experiments yielded the air gap discharge characteristics between the phase-selection switch contacts, and based on this, the pre-breakdown time of the switch contacts under different applied voltages was determined. This experiment focused on the circuit breaker's pre-breakdown characteristics under stable voltage. The experimental equipment mainly included a power supply, a permanent magnet circuit breaker, a voltage divider, and a protective resistor. The power supply voltage was generated by a DC high-voltage generator with an adjustable range of ±150kV. The circuit breaker voltage rating was 35kV, meeting the voltage rating of onboard circuit breakers used in heavy-duty locomotives, with a 100mm spacing between the circuit breaker ports. The voltage divider was connected in parallel with the circuit breaker to regulate the contact gap voltage. A 2MΩ protective resistor was added to prevent overcurrent damage to the circuit breaker. The test method is carried out in accordance with the procedure specified in GB / T16927.1-2011 (Class II Test). A DC high voltage generator generates DC power to supply the test circuit. The contact gap voltage is changed by adjusting the voltage divider. On the basis of ensuring the normal closing of the circuit breaker, the voltage between the contacts is increased. The discharge voltage is obtained by the step-up method (refer to GB / T11022-2011). The discharge gap voltage and pre-breakdown time during the closing process of the moving contact are measured. The pre-breakdown time under different voltages is obtained. The effective number of tests is 10-20.

[0115] Based on experimental data, the relationship between the applied voltage and the pre-breakdown time during the circuit breaker's closing process was statistically obtained. All data were fitted into a curve, showing that the pre-breakdown time decreases as the applied voltage increases. Analysis of the fitted curve yielded the following relationship between the applied voltage and the pre-breakdown time for a 35kV permanent magnet vacuum circuit breaker (100mm break spacing):

[0116]

[0117] u is the voltage applied between the circuit breaker contacts in kV, and t is the pre-breakdown time of the circuit breaker in ms. Substituting u = 27.5kV into the above formula, we can obtain the pre-breakdown time t = 4.51ms. Under the voltage level of high-speed railways, the pre-breakdown time of this permanent magnet circuit breaker is relatively small, which can achieve the purpose of fast closing.

[0118] (3) Circuit breaker phase-controlled closing scheme

[0119] In a preferred embodiment, several closing speeds for circuit breaker closing are set based on the first and second effects; the closing time is calculated according to the circuit breaker contact travel and closing speed; the circuit breaker closing pre-breakdown characteristic includes the circuit breaker closing pre-breakdown time, the sum of the closing time and the waiting time does not exceed the pre-breakdown time, so that the contacts close exactly to the target phase angle at the end of the closing time, and the overvoltage generated by the circuit breaker closing is minimized, the waiting time is the time from receiving the circuit breaker closing command to the contacts starting to close at the initial phase angle; the starting phase angle interval for circuit breaker closing is determined according to the closing time, target phase angle, waiting time and pre-breakdown time, so that the circuit breaker closes at the starting phase angle interval.

[0120] Specifically, by analyzing the breakdown characteristics of the circuit breaker, a timing diagram of the circuit breaker closing process is obtained, such as... Figure 13 As shown. Based on the circuit breaker's pre-breakdown characteristics and the requirements of phase selection operation on closing speed, the closing speed should be greater than a certain value so that the absolute value of the slope of the pre-breakdown characteristic curve is greater than the slope of the voltage curve across the circuit breaker contacts. The specific process is as follows:

[0121] (1) Select the circuit breaker closing speed v1, and calculate the circuit breaker operating time T based on the circuit breaker contact stroke. cls Then, based on the analysis results of the dispersion of the circuit breaker mechanism, the target closing phase angle α is selected (considering the load characteristics of heavy-duty locomotives, the value is taken as 0° in this embodiment of the invention) so that the pre-breakdown voltage is minimized within the dispersion range of the circuit breaker closing time. (2) The phase selection controller monitors the zero point of the power supply voltage. (3) After receiving the closing command, the phase selection controller takes the next zero-crossing point of the power supply voltage as the reference point, combined with the circuit breaker closing time T. cls and controller calculation time T c1 Calculate the time delay T required to reach the optimal target phase. d1 (4) While waiting for T d1 Then, the controller issues a command to close the circuit, causing the contacts to close at the target phase (40° to 65° in this embodiment of the invention, but can also be set according to the actual scenario of the application of the invention, which is not limited here).

[0122] Phase selection closing scheme as follows Figure 14 and 15As shown. Based on the phase-controlled closing scheme of the circuit breaker and combined with the pre-breakdown characteristics of the circuit breaker during closing, a phase-controlled closing test analysis was conducted. The test used a PCS-350 phase selection control device, which is small in size, has high measurement accuracy, strong anti-interference ability, and complete phase selection closing and opening functions, and can adapt to complex electromagnetic compatibility environments. Using this device to control the permanent magnet circuit breaker, the pre-breakdown time and pre-breakdown voltage under different closing phase angles were obtained by closing at different phases.

[0123] According to the formula relating the applied voltage between the breaks of a 35kV permanent magnet vacuum circuit breaker (100mm break spacing) to the pre-breakdown time, when the voltage across the circuit breaker is 27.5kV, the pre-breakdown time is 4.51ms. When conducting phase-controlled closing tests on this permanent magnet circuit breaker, the above pre-breakdown time is used as a reference. Figure 14 It can be seen that when the closing phase angles are -8° and 15°, the corresponding pre-breakdown time is 4.51ms. Therefore, when closing within the (-8°, 15°) interval, the pre-breakdown time varies between (0ms, 4.51ms), which meets the requirements for the fast response of the circuit breaker. Figure 15 It can be seen that when the closing phase angle is within the range of (-8°, 15°), the pre-breakdown voltage varies between (0kV, 8.54kV). The pre-breakdown voltage is relatively small, which meets the safety requirements for circuit breakers in electrified railways. The analysis of the experimental results shows that the smaller the closing phase angle, the shorter the pre-breakdown time and the lower the pre-breakdown voltage. For electrified railways, a circuit breaker closing phase angle between (-8°, 15°) can effectively reduce system overvoltage.

[0124] Therefore, this invention adopts the above-mentioned phase-controlled closing method, establishes equivalent mathematical models for heavy-load locomotives, traction substations, AT substations and traction networks, and then establishes a vehicle-network-substation simulation model to analyze the impact of different line loads on phase-selective closing. Based on the analysis results of the circuit breaker breakdown characteristics, the phase-selective closing scheme is determined. Through experimental verification, it is determined that the phase-selective closing scheme can achieve the purpose of reducing the overvoltage of the closing system.

[0125] Another embodiment of the present invention also provides a phase-controlled closing device 100 for heavy-duty locomotive circuit breakers, such as... Figure 16 As shown, it includes:

[0126] Mathematical model building module 110 is used to establish equivalent mathematical models of heavy-duty locomotives, traction networks, traction substations and AT stations;

[0127] The simulation model building module 120 establishes an overvoltage simulation model based on the equivalent mathematical models of heavy-duty locomotives, traction networks, traction substations, and AT stations.

[0128] Simulation module 130 uses the overvoltage simulation model to simulate various operating conditions of heavy-duty locomotives and obtain the influence of load on circuit breaker phase selection and closing under different operating conditions;

[0129] The closing phase control module 140 determines the phase control closing scheme of the circuit breaker based on the influence of load on the phase selection closing of the circuit breaker under different operating conditions and the pre-breakdown characteristics of the circuit breaker closing.

[0130] The specific implementation of the embodiments of the present invention can be referred to the above-described embodiment of a phase-controlled closing method, and will not be repeated here.

[0131] Another embodiment of the present invention provides a heavy-duty locomotive circuit breaker, including an arc-extinguishing chamber, a disconnecting switch, a control and operating mechanism, and a compressed air supply system, as well as a phase selection controller for executing a phase-controlled closing method described in the above embodiment; the phase selection controller is connected to the control and operating mechanism and is used to send a closing command to the control and operating mechanism, so that the control and operating mechanism performs a closing operation based on the closing command. This enables the heavy-duty locomotive circuit breaker to effectively suppress overvoltage and prevent breakdown during the closing process, which is beneficial to improving the safety of electrified railway control technology and solves the technical problem of operational overvoltage caused by random closing in existing heavy-duty locomotive circuit breakers.

[0132] Another embodiment of the present invention also provides an electronic device, such as... Figure 17 As shown, the device 2 includes a memory 21, a processor 22, and a computer program 23 stored in the memory 21 and executable on the processor 22. When the processor 22 executes the computer program 23, it implements the steps of a phase-controlled closing method as described in the above embodiment.

[0133] Another embodiment of the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of a phase-controlled closing method as described in the above embodiment.

[0134] Another embodiment of the present invention provides a computer program product, including a computer program that, when executed by a processor, implements the steps of a phase-controlled closing method as described in the above embodiment.

[0135] The embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A phase-controlled closing method for a heavy-duty locomotive circuit breaker, characterized in that, include: Establish equivalent mathematical models for heavy-duty locomotives, traction networks, traction substations, and AT stations; An overvoltage simulation model is established based on the equivalent mathematical models of heavy-duty locomotives, traction networks, traction substations, and AT stations. The overvoltage simulation model was used to simulate various operating conditions of heavy-load locomotives to obtain the influence of load on circuit breaker phase selection and closing under different operating conditions; The overvoltage simulation model is used to simulate various operating conditions of heavy-load locomotives to obtain the influence of load on the phase selection and closing of circuit breakers under different operating conditions. This includes: using the overvoltage simulation model to simulate the single-car operation of heavy-load locomotives and analyzing the first influence of the closing time of the circuit breaker on the closing overvoltage; based on the first influence, the relationship between the speed of the heavy-load locomotive and the load impedance is analyzed; based on the relationship, the overvoltage simulation model is used to simulate the multi-car operation of heavy-load locomotives and analyze the second influence of the load of the heavy-load locomotive traveling on the same line or adjacent line on the closing overvoltage of the circuit breaker. Based on the influence of load on the phase selection and closing of the circuit breaker under different operating conditions and the pre-breakdown characteristics of the circuit breaker, the phase-controlled closing scheme of the circuit breaker is determined. This scheme includes: setting several closing speeds for the circuit breaker based on the first and second influences; calculating the closing time based on the circuit breaker contact travel and closing speed; the pre-breakdown characteristics of the circuit breaker include the pre-breakdown time, where the sum of the closing time and the waiting time does not exceed the pre-breakdown time, so that the contacts close precisely to the target phase angle at the end of the closing time, and minimizes the overvoltage generated by the circuit breaker closing; the waiting time is the time from receiving the circuit breaker closing command to the contacts starting to close at the initial phase angle; and determining the initial phase angle range for circuit breaker closing based on the closing time, target phase angle, waiting time, and pre-breakdown time, so that the circuit breaker closes within the initial phase angle range.

2. The phase-controlled closing method as described in claim 1, characterized in that, The equivalent mathematical model of a heavy-haul locomotive includes: The vehicle roof high-voltage cable transmission line model is constructed using a π-type lumped parameter model, the voltage transformer winding circuit is constructed using a saturable transformer model, the first traction transformer winding circuit is constructed using a multi-winding transformer, and the four-quadrant converter circuit is constructed using a single-phase two-level topology. The vehicle roof high-voltage cable transmission line model is used to transmit electrical energy.

3. The phase-controlled closing method as described in claim 2, characterized in that, The voltage transformer winding circuit includes: First resistor, first inductor, second resistor, second inductor, third resistor, third inductor and core winding transformer; The first resistor is connected in series with the first inductor, and the first inductor is connected in parallel with the third resistor; The second resistor is connected in series with the second inductor, and the secondary side of the iron core winding transformer is connected in parallel with the second resistor. The third resistor is connected in parallel with the third inductor, and the third inductor is connected in parallel with the primary side of the iron core winding transformer.

4. The phase-controlled closing method as described in claim 2, characterized in that, The first traction transformer winding circuit includes: The fourth resistor, the fourth inductor, the fifth resistor, the fifth inductor, the sixth resistor, the sixth inductor, the seventh resistor, the seventh inductor, and the three-winding transformer with an iron core; The fourth resistor is connected in series with the fourth inductor, and the fourth inductor is connected in parallel with the seventh resistor; The fifth resistor is connected in series with the fifth inductor, and the secondary side of the three-winding iron-core transformer is connected in parallel with the fifth resistor. The sixth resistor is connected in series with the sixth inductor, and the third side of the three-winding iron-core transformer is connected in parallel with the sixth resistor. The seventh resistor is connected in parallel with the seventh inductor, and the seventh inductor is connected in parallel with the primary side of the three-winding iron-core transformer.

5. The phase-controlled closing method as described in claim 2, characterized in that, The four-quadrant converter circuit includes: Oscilloscope, eighth inductor, eighth resistor, first bipolar transistor, second bipolar transistor, third bipolar transistor, fourth bipolar transistor, first capacitor and ninth resistor; One end of the oscilloscope is connected to the first end of the eighth inductor, the second end of the eighth inductor is connected to the first end of the eighth resistor, the second end of the eighth resistor is connected to the emitter of the first bipolar transistor, and the other end of the oscilloscope is connected to the emitter of the third bipolar transistor. The emitter of the first bipolar transistor is connected to the collector of the second bipolar transistor, and the emitter of the third bipolar transistor is connected to the collector of the fourth bipolar transistor; the collector of the first bipolar transistor is connected to the collector of the third bipolar transistor, and the emitter of the second bipolar transistor is connected to the emitter of the fourth bipolar transistor. The collector of the third bipolar transistor is connected to the first terminal of the first capacitor, and the emitter of the fourth bipolar transistor is connected to the second terminal of the first capacitor. The first terminal of the first capacitor is connected to the first terminal of the ninth resistor, and the second terminal of the first capacitor is connected to the second terminal of the ninth resistor.

6. The phase-controlled closing method as described in claim 1, characterized in that, The equivalent mathematical model of the traction network includes: The multi-conductor transmission line model includes electrical parameters such as series impedance and parallel admittance.

7. The phase-controlled closing method as described in claim 6, characterized in that, Impedance parameters include: The self-impedance of a conductor and the mutual impedance between two conductors; No. Root wire self-impedance The calculation formula is: ； No. root wire and the first Mutual impedance between the conductors The calculation formula is: ； in, The effective resistance per unit length of the conductor. The earth's own resistance, The permeability of free space, For the current frequency, The equivalent depth for the conductor and the ground loop. Let be the equivalent radius of the conductor. This represents the vertical distance between the two conductors.

8. The phase-controlled closing method as described in claim 6, characterized in that, Admittance parameters include: The self-potential coefficient of a conductor and the mutual potential coefficient between two conductors; No. Root conductor self-potential coefficient The calculation formula is: ； No. root wire and the first mutual potential coefficient between the conductors The calculation formula is: ； in, The dielectric constant of air is For the first root wire and the first Mirror distance between the root wires For the first root wire and the first Spatial distance between the wires For the first The equivalent radius of the conductor. For the first The height of the conductor above the ground.

9. The phase-controlled closing method as described in claim 1, characterized in that, The equivalent mathematical model of a traction substation includes: The second traction transformer winding circuit adopts either the Scott connection method or the V / X connection method.

10. The phase-controlled closing method as described in claim 9, characterized in that, The second traction transformer winding circuit includes: First single-phase transformer and second single-phase transformer; The primary winding of the first single-phase transformer is led out at both ends. The first end of the primary winding is connected to phase A of the power system, and the second end of the primary winding is connected to phase B of the power system. One end of the primary winding of the second single-phase transformer is led out and connected to phase C of the power system. The other end of the non-primary winding is connected to the midpoint of the primary winding of the first single-phase transformer.

11. The phase-controlled closing method as described in claim 1, characterized in that, The equivalent mathematical models of AT include: In an autotransformer winding circuit, the secondary winding of the autotransformer shares a portion of the primary winding with the secondary winding.

12. The phase-controlled closing method as described in claim 11, characterized in that, The autotransformer winding circuit includes: Ninth inductor, tenth inductor, and tenth resistor; The ninth inductor is connected in series with the tenth inductor, and the tenth inductor is connected in parallel with the tenth resistor.

13. The phase-controlled closing method as described in claim 1, characterized in that, Based on the equivalent mathematical models of heavy-haul locomotives, traction networks, traction substations, and AT substations, an overvoltage simulation model is established, including: The equivalent mathematical models of heavy-duty locomotives, traction networks, traction substations, and AT stations are converted into corresponding simulation models and simulation parameters are set. Based on the actual wiring principle of electrified railways, the simulation models of heavy-duty locomotives, traction substations, and AT substations are connected to the traction network simulation model to construct an overvoltage simulation model.

14. The phase-controlled closing method as described in claim 1, characterized in that, The second impact includes: The first overvoltage is greater than the second overvoltage. The first overvoltage is the overvoltage generated by the load of the heavy-load locomotive traveling on the same line closing the circuit breaker. The second overvoltage is the overvoltage generated by the load of the heavy-load locomotive traveling on an adjacent line closing the circuit breaker. The third overvoltage is greater than the fourth overvoltage. The third overvoltage is the overvoltage generated by the first load of the heavy-load locomotive running on the same line closing the circuit breaker. The fourth overvoltage is the overvoltage generated by the second load of the heavy-load locomotive running on the same line closing the circuit breaker. The first load impedance of the first load is greater than the second load impedance of the second load, or the distance between the first load and the first load of the heavy-load locomotive is less than the distance between the second load and the second load of the heavy-load locomotive. The fifth overvoltage is greater than the sixth overvoltage. The fifth overvoltage is the overvoltage generated by the heavy-load locomotive traveling at the first speed closing the circuit breaker, and the sixth overvoltage is the overvoltage generated by the heavy-load locomotive traveling at the second speed closing the circuit breaker. The first speed is greater than the second speed.

15. A phase-controlled closing method as described in claim 14, characterized in that, The circuit breaker is a bistable permanent magnet vacuum circuit breaker, which uses permanent magnets to realize the opening and closing of the circuit breaker.

16. The phase-controlled closing method as described in claim 15, characterized in that, The pre-breakdown characteristic of a circuit breaker includes the relationship between the voltage applied between the circuit breaker contacts and the pre-breakdown time: ;in, The voltage value applied between the circuit breaker contacts. This refers to the pre-breakdown time of the circuit breaker.

17. A phase-controlled closing device for a heavy-duty locomotive circuit breaker, characterized in that, include: The mathematical model building module is used to establish equivalent mathematical models of heavy-duty locomotives, traction networks, traction substations, and AT stations. The simulation model building module establishes an overvoltage simulation model based on the equivalent mathematical models of heavy-duty locomotives, traction networks, traction substations, and AT stations. The simulation module uses the overvoltage simulation model to simulate various operating conditions of heavy-duty locomotives and obtain the impact of load on circuit breaker phase selection and closing under different operating conditions. The overvoltage simulation model is used to simulate various operating conditions of heavy-load locomotives to obtain the influence of load on the phase selection and closing of circuit breakers under different operating conditions. This includes: using the overvoltage simulation model to simulate the single-car operation of heavy-load locomotives and analyzing the first influence of the closing time of the circuit breaker on the closing overvoltage; based on the first influence, the relationship between the speed of the heavy-load locomotive and the load impedance is analyzed; based on the relationship, the overvoltage simulation model is used to simulate the multi-car operation of heavy-load locomotives and analyze the second influence of the load of the heavy-load locomotive traveling on the same line or adjacent line on the closing overvoltage of the circuit breaker. The phase-controlled closing module determines the phase-controlled closing scheme of the circuit breaker based on the influence of load on the phase-selective closing of the circuit breaker under different operating conditions and the pre-breakdown characteristics of the circuit breaker. This includes: setting several closing speeds for the circuit breaker based on the first and second influences; calculating the closing time based on the circuit breaker contact travel and closing speed; the pre-breakdown characteristics of the circuit breaker include the pre-breakdown time, where the sum of the closing time and the waiting time does not exceed the pre-breakdown time, so that the contacts close precisely to the target phase angle at the end of the closing time, and the overvoltage generated by the circuit breaker closing is minimized; the waiting time is the time from receiving the circuit breaker closing command to the contacts starting to close at the initial phase angle; and determining the initial phase angle range for circuit breaker closing based on the closing time, target phase angle, waiting time, and pre-breakdown time, so that the circuit breaker closes within the initial phase angle range.

18. A heavy-duty locomotive circuit breaker, comprising an arc-extinguishing chamber, a disconnecting switch, a control and operating mechanism, and a compressed air supply system, characterized in that, Also includes: A phase selection controller that performs a phase-controlled closing method as described in any one of claims 1 to 16; The phase selection controller is connected to the control and operation mechanism and is used to send a closing command to the control and operation mechanism so that the control and operation mechanism can perform a closing operation based on the closing command.

19. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of a phase-controlled closing method as described in any one of claims 1 to 16.

20. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of a phase-controlled closing method as described in any one of claims 1 to 16.

21. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of a phase-controlled closing method as described in any one of claims 1 to 16.

Images