A method for designing a magnetic field of a magnetic blow coil of a marine high-arc-voltage quick mechanical switch

Abstract

This invention discloses a magnetic field design method for a marine high-arc voltage fast mechanical switch magnetic blow-out coil, comprising: S1, establishing a 3D transient magnetic field simulation model of the magnetic blow-out coil, setting coil excitation, simulating the current and magnetic field strength of the magnetic blow-out coil under different energy storage capacitor values, and comparing and analyzing the changing trends of current and magnetic field; S2, simplifying the structure of the magnetic blow-out coil and arc-extinguishing chamber, establishing a 2D equivalent simulation model based on RZ coordinates, combining the simulation of the fast mechanical switch opening process with the magnetic blow-out coil simulation, and simulating the magnetic blow-out coil current, the opening coil current, and the opening motion displacement. This invention simulates the current and magnetic field of the magnetic blow-out coil through 3D transient magnetic field simulation and 2D equivalent RZ model simulation, analyzes the influence of the energy storage capacitor value and charging voltage of the discharge circuit on the current and magnetic field, and realizes the simulation design of the magnetic blow-out coil.

Description

Technical Field

[0001] This invention relates to the field of marine integrated power system technology, specifically to a method for designing the magnetic field of a high-arc voltage fast mechanical switch magnetic blowout coil for a marine natural commutation type medium-voltage DC hybrid circuit breaker. Background Technology

[0002] Existing hybrid DC circuit breakers all employ vacuum fast mechanical switches and auxiliary control circuits for forced commutation DC interruption in their main branches. While the forced commutation method, by introducing auxiliary commutation equipment, improves the reliability of current transfer, it also increases the cost and size of the DC circuit breaker and reduces its reliability, hindering the large-scale application of medium-voltage DC circuit breakers in IPS (Insulated Switchgear). Although the application of natural commutation is limited by the arc voltage of the vacuum fast mechanical switches, its advantages of simple structure and low cost make it a feasible solution for achieving compact and low-cost DC circuit breakers, which is of great significance for the widespread application of medium-voltage hybrid DC circuit breakers in IPS.

[0003] To address the issue that the Lorentz force generated in the transverse magnetic contact is insufficient to propel the electric arc when the current flowing through the vacuum fast mechanical switch is small, an external magnetic field needs to be generated by a magnetic blowout coil to compensate for the deficiency of its own magnetic field. The magnitude and waveform of the external magnetic field have a significant impact on the magnitude and variation of the arc voltage. Therefore, the simulation and design of the magnetic field of the magnetic blowout coil are of great importance. Currently, in-depth research on the relationship between the magnetic field of the magnetic blowout coil and the current and displacement is still lacking.

[0004] Among existing related patent technologies, such as the electromagnetic repulsion switch contact magnetic blow-out method disclosed in patent document (CN108807045B), which uses a trip coil to drive a magnetic field to achieve arc blowing, it only achieves magnetic field reuse and does not conduct quantitative research on the relationship between magnetic field, current, and displacement for marine low-current operating conditions and arc voltage enhancement requirements. It cannot achieve precise design and timing control of the magnetic field of the magnetic blow-out coil, and there is no guiding basis for timing matching of magnetic field peak and current peak. For example, the DC electromagnetic switch series multi-break arc simulation method disclosed in patent document (CN119378237A) achieves multi-break arc simulation based on magnetohydrodynamics, but it does not involve dedicated 3D transient magnetic field simulation and 2D RZ equivalent simplified model for magnetic blow-out coils. It cannot quickly complete the parameter design of magnetic blow-out coils and does not have the ability for rapid engineering simulation.

[0005] In summary, existing technologies cannot provide a precise, efficient, and engineerable magnetic field design method for marine fast mechanical switches, which restricts the application of natural commutation type medium-voltage DC hybrid circuit breakers in the marine field. Summary of the Invention

[0006] This invention aims to propose a design method for the magnetic field of a high-arc-voltage fast mechanical switch magnetic blowout coil used in a marine natural commutation type medium-voltage DC hybrid circuit breaker. By studying the influence of external transverse magnetic field and tripping characteristics on the arc voltage of the DC breaking arc of the vacuum fast mechanical switch, the magnetic blowout coil's magnetic field is simulated and designed. Since the magnitude and waveform of the applied magnetic field have a significant impact on the magnitude and variation process of the arc voltage, the simulation and design of the magnetic blowout coil's magnetic field is of great importance.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A method for designing the magnetic field of a marine high-arc voltage fast mechanically switched blowout coil includes: S1. Establish a 3D transient magnetic field simulation model of the magnetic blowout coil, set the coil excitation, simulate the current and magnetic field strength of the magnetic blowout coil under different energy storage capacitor values, and compare and analyze the changing trends of current and magnetic field. S2. Simplify the structure of the magnetic blow-out coil and the arc-extinguishing chamber, establish a 2D equivalent simulation model based on RZ coordinates, combine the simulation of the fast mechanical switch opening process with the magnetic blow-out coil simulation, and simulate the magnetic blow-out coil current, the opening coil current and the opening motion displacement.

[0009] Furthermore, in step S1, the coil excitation adopts the energy storage capacitor discharge excitation, and the simulation variables include the energy storage capacitor value and the charging voltage.

[0010] Furthermore, in step S1, the simulated energy storage capacitor values ​​include 2400uF, 3100uF, and 3700uF, and the charging voltages include 1400V, 1600V, and 1800V.

[0011] Furthermore, the parameters of the energy storage capacitor discharge circuit include: the energy storage capacitor inductance ESL is 75nH, the energy storage capacitor resistance ESR is 0.4mΩ, the discharge circuit stray resistance is 2mΩ, and the discharge circuit stray inductance is 3μH.

[0012] Furthermore, in step S1, magnetic field strength data is obtained through the arc center marker point, and the peak magnetic field lags the peak current by 0.3ms.

[0013] Furthermore, in step S1, as the capacitance of the energy storage capacitor increases, the current and magnetic field strength of the magnetic blow-out coil increase monotonically, and the peak magnetic induction intensity reaches 28.7mT under a capacitance of 3700uF.

[0014] Furthermore, in step S2, in order to accelerate the simulation process, the magnetic blowout coil and the arc-extinguishing chamber are simplified, and the 3D model is simplified to an equivalent RZ coordinate 2D model.

[0015] Furthermore, in step S2, the 2D equivalent simulation model couples the tripping motion displacement and synchronously outputs the magnetic blow-out coil current, tripping coil current and displacement curves.

[0016] Furthermore, the magnetic blowout coil generates a transverse magnetic field perpendicular to the direction of the arc current inside the arc extinguishing chamber, thereby increasing the arc voltage drop to meet the requirements of natural commutation.

[0017] Furthermore, the method is applicable to vacuum fast mechanical switches of marine natural commutation type medium-voltage DC hybrid circuit breakers.

[0018] Compared with the prior art, the present invention has the following significant advantages: This invention simulates the current and magnetic field of a magnetic blowout coil through 3D transient magnetic field simulation and 2D equivalent RZ model simulation, analyzes the influence of the energy storage capacitor value and charging voltage of the discharge circuit on the current and magnetic field, and realizes the simulation design of the magnetic blowout coil.

[0019] (1) The 3D transient magnetic field simulation of the magnetic blow-out coil compares the current and magnetic field strength of the magnetic blow-out coil under different energy storage capacitor capacities. As the energy storage capacitor increases, the current and magnetic field generated by the magnetic blow-out coil both increase. At the same time, the peak value of the magnetic field generated by the coil lags behind the peak value of the current by about 0.3ms, which provides a reference for the control timing of the magnetic field of the magnetic blow-out coil.

[0020] (2) 2D equivalent RZ model simulation: For different energy storage capacitor values ​​and charging voltages, the magnetic blow-out coil current, the trip coil current and the trip displacement were simulated. At the same time, the magnetic field distribution cloud map in the switch arc-extinguishing chamber was given, which played a guiding role in the parameter design of the magnetic blow-out coil. Attached Figure Description

[0021] Figure 1 A simplified 3D model of a 3mm magnetic blow-out coil for rapid mechanical switching. Figure 2 shows the discharge circuit diagram of the magnetic blowout coil; Figure 3 Excitation setup diagram for coil 1; Figure 4 A schematic diagram of the arc center marker point; Figure 5 Diagram showing the excitation setup for coil 2; Figure 6 The current curve of the blowout coil and the magnetic field strength at the center mark of the arc are shown for an energy storage capacitor of 2400uF and a capacitor charging voltage of 1400V. Figure 7 The current curve of the blowout coil and the magnetic field strength at the center mark of the arc are shown for a 3100uF energy storage capacitor and a capacitor charging voltage of 1400V. Figure 8The magnetic blowout coil current curve and the magnetic field strength at the center mark of the arc are shown for an energy storage capacitor of 3700uF and a capacitor charging voltage of 1400V. Figure 9 A summary of the current curve of the magnetic blowout coil and the magnetic field strength at the arc center marker; Figure 10 This is the equivalent RZ model diagram; Figure 11 Simulation results are given when the energy storage capacitor of the magnetic blowout coil is 2500uF and the energy storage voltage is 1400V. Figure 12 Simulation results are given when the energy storage capacitor of the magnetic blowout coil is 2500uF and the energy storage voltage is 1600V. Figure 13 Simulation results are given when the energy storage capacitor of the magnetic blowout coil is 2500uF and the energy storage voltage is 1800V. Figure 14 Simulation results are given when the energy storage capacitor of the magnetic blowout coil is 3100uF and the energy storage voltage is 1400V. Figure 15 Simulation results are given when the energy storage capacitor of the magnetic blowout coil is 3100uF and the energy storage voltage is 1600V. Figure 16 Simulation results are given when the energy storage capacitor of the magnetic blowout coil is 3100uF and the energy storage voltage is 1800V. Figure 17 Simulation results are given when the magnetic blowout energy storage capacitor is 3700uF and the energy storage voltage is 1400V. Figure 18 Simulation results are given when the magnetic blowout energy storage capacitor is 3700uF and the energy storage voltage is 1600V. Figure 19 Simulation results are given when the magnetic blowout energy storage capacitor is 3700uF and the energy storage voltage is 1800V. in, Figures 11-19 (a) shows the magnetic field distribution on the center line when the current is at its peak, (b) shows the magnetic field cloud diagram of the blow-out coil when the current is at its peak, and (c) shows the simulation results of the trip coil, blow-out coil current and switch displacement. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0023] The magnetic field design method of the high arc voltage fast mechanical switch magnetic blow-out coil for marine natural commutation type medium voltage DC hybrid circuit breaker proposed in this invention is mainly divided into magnetic blow-out coil simulation model establishment, magnetic blow-out coil 3D transient magnetic field simulation, and 2D equivalent RZ model simulation.

[0024] 1. Simulation model of magnetic blowout coil The magnetic blowout coil is an important component for generating high arc voltage. Its principle is that the energy storage capacitor discharges to the magnetic blowout coil through the discharge device. The magnetic blowout coil generates a transverse magnetic field that is perpendicular to the current in the arc-extinguishing chamber. This magnetic field causes the electrons of the arc current in the arc-extinguishing chamber to move laterally, thereby increasing the voltage drop of the arc.

[0025] Since the relative permeability of all components inside the arc-extinguishing chamber is 1, the same as that of air and vacuum, it will not affect the magnetic field distribution. Therefore, the three-dimensional model can be simplified to an equivalent model in the RZ coordinate system (see...). Figure 1 ).

[0026] The discharge circuit of the magnetic blowout coil is as follows Figure 2 As shown in Table 1, the external circuit parameters are as follows.

[0027] Table 1 External Circuit Parameters

[0028] 2. 3D transient magnetic field simulation of a blowout coil (1) Incentive settings Set the excitation for coil 1 and coil 2, see [link / reference]. Figure 3 Mark the arc center monitoring point (4, 5) and simulate the current and magnetic field of capacitors 2400uF, 3100uF, and 3700uF at 1400V respectively: (2) Simulation results Simulation results of the magnetic blowout coil current and magnetic field under a 2400uF energy storage capacitor and a capacitor charging voltage of 1400V are as follows: Figure 6 As shown.

[0029] Simulation results of the magnetic blowout coil current and magnetic field under a storage capacitor of 3100uF and a capacitor charging voltage of 1400V are as follows: Figure 7 As shown.

[0030] Simulation results of the magnetic blowout coil current and magnetic field under a storage capacitor of 3700uF and a capacitor charging voltage of 1400V are as follows: Figure 8 As shown.

[0031] like Figure 9 As shown, comparing the current and magnetic field strength of the blown-out coil under different energy storage capacitors, it can be seen that with the increase of energy storage capacitor, both the current and the generated magnetic field of the blown-out coil increase. When the energy storage capacitor is 3700uF, its peak magnetic induction intensity reaches 28.7mT. In addition, simulation also shows that the peak value of the magnetic field generated by the coil lags behind the peak value of the current by about 0.3ms, which provides a reference for the control timing of the magnetic field of the blown-out coil.

[0032] 2.2D equivalent RZ model simulation Due to the large computational load and slow simulation speed of 3D simulation models, a simplified 2D simulation model based on RZ coordinates was established to accelerate the simulation process. (See...) Figure 10 The simulation of the rapid mechanical switch opening process was combined with the simulation of the magnetic blow-out coil. The simulation of the magnetic blow-out coil current, the opening coil current and the opening motion displacement were carried out. At the same time, the magnetic field distribution cloud map of the magnetic field in the switch arc-extinguishing chamber was given.

[0033] (1) Simulation results for the magnetic blowout coil with a storage capacitor of 2500uF and charging voltages of 1400V, 1600V, and 1800V are as follows: Figure 11 , Figure 12 , Figure 13 As shown.

[0034] (2) The simulation results for the magnetic blowout coil with an energy storage capacitor of 3100uF and charging voltages of 1400V, 1600V, and 1800V are as follows: Figure 14 , Figure 15 , Figure 16 As shown.

[0035] (3) The simulation results for magnetic blowout energy storage capacitor of 3700uF and charging voltage of 1400V, 1600V and 1800V are as follows: Figure 17 , Figure 18 , Figure 19 As shown.

[0036] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the concept and scope of the present invention. Therefore, all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A method for designing a magnetic field of a magnetic blow coil of a high arc voltage fast mechanical switch for marine use, characterized in that, include: S1. Establish a 3D transient magnetic field simulation model of the magnetic blowout coil, set the coil excitation, simulate the current and magnetic field strength of the magnetic blowout coil under different energy storage capacitor values, and compare and analyze the changing trends of current and magnetic field. S2. Simplify the structure of the magnetic blow-out coil and the arc-extinguishing chamber, establish a 2D equivalent simulation model based on RZ coordinates, combine the simulation of the fast mechanical switch opening process with the magnetic blow-out coil simulation, and simulate the magnetic blow-out coil current, the opening coil current and the opening motion displacement.

2. The method for designing the magnetic field of a marine high-arc voltage rapid mechanical switch blowout coil according to claim 1, characterized in that, In step S1, the coil excitation is achieved by discharging the energy storage capacitor, and the simulation variables include the capacitance value of the energy storage capacitor and the charging voltage.

3. The method for designing the magnetic field of a marine high-arc voltage rapid mechanical switch blowout coil according to claim 2, characterized in that, In step S1, the simulated energy storage capacitor values ​​include 2400uF, 3100uF, and 3700uF, and the charging voltages include 1400V, 1600V, and 1800V.

4. The method for designing the magnetic field of a marine high-arc voltage rapid mechanical switch blowout coil according to claim 2, characterized in that, The parameters of the energy storage capacitor discharge circuit include: the energy storage capacitor ESL is 75nH, the energy storage capacitor ESR is 0.4mΩ, the stray resistance of the discharge circuit is 2mΩ, and the stray inductance of the discharge circuit is 3μH.

5. The method for designing the magnetic field of a marine high-arc voltage rapid mechanical switch blowout coil according to claim 1, characterized in that, In step S1, magnetic field strength data is obtained through the arc center marker point, and the peak magnetic field lags the peak current by 0.3ms.

6. The method for designing the magnetic field of a marine high-arc voltage fast mechanical switch blowout coil according to claim 1, characterized in that, In step S1, as the capacitance of the energy storage capacitor increases, the current and magnetic field strength of the magnetic blow-out coil increase monotonically, and the peak magnetic induction intensity reaches 28.7mT under a capacitance of 3700uF.

7. The method for designing the magnetic field of a marine high-arc voltage fast mechanical switch blowout coil according to claim 1, characterized in that, In step S2, to accelerate the simulation process, the magnetic blowout coil and arc-extinguishing chamber are simplified, and the 3D model is simplified to an equivalent 2D model in RZ coordinates.

8. The method for designing the magnetic field of a marine high-arc voltage fast mechanical switch blowout coil according to claim 1, characterized in that, In step S2, the 2D equivalent simulation model couples the tripping motion displacement and synchronously outputs the magnetic blow-out coil current, tripping coil current and displacement curve.

9. The method for designing the magnetic field of a marine high-arc voltage fast mechanical switch blowout coil according to claim 1, characterized in that, The magnetic blowout coil generates a transverse magnetic field perpendicular to the direction of the arc current inside the arc extinguishing chamber, thereby increasing the arc voltage drop to meet the requirements of natural commutation.

10. The method for designing the magnetic field of a marine high-arc voltage fast mechanical switch blowout coil according to claim 1, characterized in that, The method is applicable to vacuum fast mechanical switches of marine natural commutation type medium-voltage DC hybrid circuit breakers.

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