Outdoor metal armored voltage transformer for locomotive

Abstract

The invention relates to the technical field of electrical equipment, in particular to an outdoor metal armored voltage transformer for a locomotive. The outdoor metal armored voltage transformer comprises a metal armored shell, a coil assembly and an insulation filling layer filled in the metal armored shell, the coil assembly is arranged in the metal armored shell and comprises an iron core, a primary coil and a secondary coil, the secondary coil is arranged on the iron core in a sleeving mode, and the insulation filling layer is filled in the metal armored shell. And the primary coil is sleeved on the secondary coil. The outdoor metal armored voltage transformer has good anti-resonance and anti-overvoltage capabilities.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical equipment, and in particular to an outdoor metal-clad voltage transformer for locomotives. Background Art

[0002] Outdoor voltage transformers (VTs) play a crucial role in locomotive power systems, measuring grid voltage and providing data support for stable power system operation. However, existing solutions for outdoor VTs in locomotives still have some shortcomings. Variability in manufacturing processes and materials, as well as factors such as temperature and frequency, can affect the VT's measurement accuracy, leading to measurement errors. Environmental factors such as temperature, altitude, humidity, dust, and chemical corrosion in the locomotive's operating environment can damage the VT's insulation material, degrading its performance. Traditional outdoor VTs are complex, consisting of multiple components and assemblies, which increases manufacturing and installation challenges. Ferroresistance is a unique physical phenomenon that occurs when current passes through inductive elements with ferromagnetic properties, such as VTs and transformers. When system parameters meet certain conditions, the inductive element resonates in the system, causing severe distortion of the current and voltage waveforms and potentially generating excessively high voltage peaks, a phenomenon known as ferroresonance overvoltage. Ferroresistance overvoltage not only increases core losses in the transformer core, affecting its normal operation and even damaging the transformer, but also poses a serious threat to the stable operation of the power system. During locomotive operation, various overvoltage phenomena may occur, such as switching overvoltage and lightning overvoltage. These overvoltages can cause ferromagnetic resonance, placing high demands on the voltage transformer's ability to withstand resonant overvoltage. However, some existing voltage transformers perform poorly in this regard. If the resonance cannot be eliminated within a short period of time, a resonant overcurrent will form within the voltage transformer, causing damage to the transformer and compromising the safety of locomotive operation. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an outdoor metal-clad voltage transformer for locomotives in view of the above-mentioned deficiencies in the prior art, wherein the outdoor metal-clad voltage transformer has good anti-resonance and anti-overvoltage capabilities.

[0004] In order to solve the above problems, the present invention adopts the following technical solutions: An outdoor metal-clad voltage transformer for locomotives comprises a metal-clad shell, a coil assembly, and an insulating filling layer filled in the metal-clad shell. The coil assembly is arranged in the metal-clad shell. The coil assembly comprises an iron core, a primary coil, and a secondary coil. The secondary coil is sleeved on the iron core, and the primary coil is sleeved on the secondary coil.

[0005] Preferably, the metal armored shell is made of stainless steel or aluminum alloy.

[0006] Preferably, the iron core is R-shaped, with a square opening in the middle.

[0007] Preferably, an insulating frame is sleeved on the iron core, and the secondary coil is sleeved on the insulating frame.

[0008] Preferably, the interlayer insulation of the primary coil adopts a 1 / 3 lap winding method, with two layers of PMP capacitor composite insulation paper between each layer.

[0009] Preferably, an electrostatic screen is provided outside the primary coil.

[0010] Preferably, a plurality of voltage-equalizing rings are provided on the electrostatic screen.

[0011] Preferably, the outdoor metal-clad voltage transformer further includes a conductor and a terminal, wherein the terminal is used to be connected to a circuit, one end of the conductor is connected to the coil assembly, and the other end is connected to the terminal.

[0012] Preferably, terminal spring contacts are provided on the side walls of the wiring terminal.

[0013] Preferably, the outdoor metal-clad voltage transformer also includes a monitoring component, which includes a controller, a monitoring sensor, and a protective switch. The monitoring sensor and the protective switch are electrically connected to the coil component, respectively. The monitoring sensor is also electrically connected to the controller. When resonance or overvoltage is detected in the coil component, a first signal is sent to the controller. The controller is also electrically connected to the protective switch. After receiving the first signal, the protective switch is controlled to disconnect.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects:

[0015] (1) In the present invention, a metal armored shell is provided outside the voltage transformer. The metal armored shell is made of a high-strength, corrosion-resistant metal material, such as stainless steel or aluminum alloy, to provide solid physical protection, enhance the mechanical strength and electromagnetic shielding performance of the transformer, and effectively resist external electromagnetic interference and mechanical shock. This design can withstand vibration and shock during locomotive operation, as well as corrosion in harsh outdoor environments such as high temperature, humidity, and salt spray, ensuring its accuracy and reliability.

[0016] (2) In the present invention, the R-shaped open core is connected in a square shape, which reduces the risk of core saturation, reduces the no-load loss and no-load current of the core, improves the anti-resonance overvoltage capability of the transformer, improves the load capacity of the product, and improves the performance and stability of the transformer, ensuring its accuracy and reliability.

[0017] (3) In the present invention, an insulating filling layer is cast inside the metal armored shell, and the insulating filling layer has a high breakdown voltage and good heat resistance. Commonly used insulating materials include epoxy resin, polyester film, polyimide, etc. These materials not only have good electrical properties, but can also withstand high temperature environments, ensuring the insulation strength and service life of the voltage transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is an overall cross-sectional view of the outdoor metal-clad voltage transformer in the present invention.

[0019] Figure 2 This is a schematic diagram of the structure of the coil assembly in the present invention. Figure 1 .

[0020] Figure 3 This is a schematic diagram of the structure of the coil assembly in the present invention. Figure 2 .

[0021] In the figure: 100-metal armored shell, 200-coil assembly, 210-iron core, 220-primary coil, 230-secondary coil, 240-static screen, 250-gradient ring, 300-terminal, 310-terminal spring contact finger, 320-conductor, 400-insulation filling layer. DETAILED DESCRIPTION

[0022] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of the present invention.

[0023] In the description of the present invention, it should be noted that the term "upper" and the like to indicate an orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience and simplification of the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0024] In the description of the present invention, the terms “first” and “second” are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0025] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "connect," "dispose," "install," "fix," etc. should be understood in a broad sense. For example, they may refer to fixed connection, detachable connection, or integral connection; they may refer to direct connection, indirect connection through an intermediate medium, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0026] like Figure 1-Figure 3 As shown, this embodiment discloses an outdoor metal-clad voltage transformer for locomotives, which is particularly suitable for high-speed trains. In EMUs, the voltage transformer is one of the important components of the power system, mainly used to measure, protect and monitor the voltage of the EMU power supply system, and provide data support for the stable operation of the power system. Specifically, the outdoor metal-clad voltage transformer in this embodiment includes a metal armored shell 100, a coil assembly 200 and an insulating filling layer 400 filled in the interior of the metal armored shell 100, and the coil assembly 200 is arranged in the metal armored shell 100. The coil assembly 200 includes an iron core 210, a primary coil 220, and a secondary coil 230. The secondary coil 230 is sleeved on the iron core 210, and the primary coil 220 is sleeved on the secondary coil 230.

[0027] Specifically, the metal armored housing 100 is made of a high-strength, corrosion-resistant material such as stainless steel or aluminum alloy. This provides robust physical protection for the internal coil assembly 200, enhancing the voltage transformer's mechanical strength and electromagnetic shielding performance, effectively resisting external electromagnetic interference and mechanical shock. This design protects against vibration and shock during locomotive operation, as well as corrosion from harsh outdoor environments such as high temperature, humidity, and salt spray, ensuring the accuracy and reliability of the voltage transformer. The metal armored housing 100 utilizes a fully enclosed structure.

[0028] like Figure 2 As shown, the core 210 is R-shaped with a square opening in the center. This structural design can effectively reduce the risk of saturation of the core 210, reduce the no-load loss and no-load current of the core 210, thereby improving the voltage transformer's anti-resonance and overvoltage resistance, increasing the product's load capacity, improving the performance and stability of the current transformer, and ensuring the accuracy and reliability of the voltage transformer.

[0029] like Figure 2As shown, the iron core 210 is sheathed with an insulating frame, and the secondary coil 230 is sheathed within the insulating frame. Specifically, the iron core 210 provides a low-magnetic resistance path to enhance and concentrate the magnetic field generated by the primary coil 220, thereby improving the efficiency of the transformer. Using high-quality iron core 210 material can effectively reduce eddy current loss and hysteresis loss, improving energy conversion efficiency. The secondary coil 230, also known as the secondary winding, is primarily used to connect to measuring instruments or protection devices and output a converted low-voltage signal. The secondary coil 230 typically has a large number of turns. By varying the number of turns of the secondary coil 230, the output voltage level can be adjusted to suit the needs of subsequent equipment. The primary coil 220, also known as the primary winding, is directly connected to the high-voltage power grid and receives high-voltage input from the power supply. It has a relatively small number of turns, and when current passes through the primary coil 220, it generates a varying magnetic field within the iron core 210.

[0030] The primary coil 220 and the secondary coil 230 are both wound around the same iron core 210. Insulation material is placed between the primary and secondary coils 220, 230, as well as between the layers within each coil, to prevent short circuits. Given the high voltages involved, the physical distance between the primary and secondary coils 220, 230 must also meet certain electrical clearance standards to prevent potential safety hazards from arcing.

[0031] Furthermore, the interlayer insulation of the primary coil 220 adopts a 1 / 3 lap winding method, and two layers of PMP capacitor composite insulation paper are used between each layer, which can ensure that the interlayer insulation reaches more than 6 times the conventional one.

[0032] Furthermore, an electrostatic screen 240 is provided outside the primary coil 220. The electrostatic screen 240 is mainly used to improve the electrical performance of the voltage transformer or. The electrostatic screen 240 can evenly distribute the electric field at the end of the coil, thereby reducing the possibility of local high field strength areas and effectively reducing local discharge phenomena. This is very important for improving the insulation level of the equipment and extending its service life. By providing additional electric field shielding, the electrostatic screen 240 helps prevent external interference from affecting the internal coil, and can protect the coil from external environmental factors such as moisture, dust, etc., further enhancing the overall insulation performance. In high-voltage equipment, especially near the end of the conductor, the potential distribution may become uneven. The electrostatic screen 240 can adjust the potential distribution in these areas through its own capacitance effect to make it more uniform, thereby reducing the problem of electrical stress concentration caused by excessive potential gradient. For voltage transformers, the electrostatic screen 240 helps to reduce the influence of stray capacitance on the measurement results, making the output signal more accurate and reliable.

[0033] Furthermore, the electrostatic shield 240 is equipped with multiple grading rings 250 to optimize the electric field distribution of the voltage transformer, reduce partial discharge, and improve insulation performance. Specifically, in high-voltage environments, uneven electric field distribution can occur, especially at the tips or edges of conductors due to geometric variations. This unevenness can lead to excessively high electric field strength in localized areas, increasing the risk of partial discharge. The grading rings 250, with their specific design (typically circular or annular), improve the electric field distribution in these areas, making it more uniform and thereby reducing local electric field strength. By adjusting the electric field distribution, the grading rings 250 can effectively reduce the occurrence of high-field intensity areas, significantly reducing partial discharge. This is crucial for protecting the insulation materials within the equipment from damage, as long-term partial discharge can cause insulation degradation and ultimately electrical failure. The grading rings 250 help prevent external electromagnetic interference from affecting internal circuits and provide additional shielding, further enhancing overall insulation performance. This not only improves the safety and reliability of the equipment but also extends its service life. For precision measuring equipment such as voltage transformers, a stable electric field distribution helps ensure accurate measurement results. The use of the grading ring 250 ensures stable operation of the equipment even under harsh operating conditions.

[0034] like Figure 1 As shown, the outdoor metal-clad voltage transformer further includes a conductor 320 and a terminal 300 . The terminal 300 is used to connect to a circuit. One end of the conductor 320 is connected to the coil assembly 200 , and the other end is connected to the terminal 300 .

[0035] Furthermore, a plurality of terminal spring contact fingers 310 are provided on the side walls of the terminal block 300. The terminal spring contact fingers 310 are components used to ensure electrical connection stability and good electrical conductivity. These contact fingers are typically made of copper or other highly conductive materials and have a certain degree of elasticity. Through their elastic deformation, they compensate for position changes caused by factors such as vibration, thermal expansion and contraction, ensuring reliable electrical contact with the mating component. Furthermore, the well-designed spring contact finger design ensures a close fit between the contact surfaces, thereby reducing contact resistance and avoiding heating problems caused by excessive resistance. The contact finger design makes it easier to connect cables or busbars to the voltage transformer, while also facilitating subsequent inspection and maintenance.

[0036] In this embodiment, the outdoor metal-clad voltage transformer further includes a monitoring assembly, which includes a controller, a monitoring sensor, and a protective switch. The monitoring sensor and the protective switch are each electrically connected to the coil assembly 200. The monitoring sensor is also electrically connected to the controller and, upon detecting resonance or overvoltage in the coil assembly 200, transmits a first signal to the controller. The controller is also electrically connected to the protective switch and, upon receiving the first signal, controls the protective switch to open.

[0037] Such a monitoring component can play a good protective role for the voltage transformer. When resonance or overvoltage is detected, measures can be taken immediately, such as cutting off the protection switch, to protect the voltage transformer from damage.

[0038] Specifically, in this embodiment, the filling layer inside the metal armored shell 100 is made of the following raw materials: 30-50 parts of trimethylolpropane triglycidyl ether, 10-30 parts of polypropylene glycol, 30-50 parts of epoxy resin, 50-70 parts of hexahydrophthalic acid bisglycidyl ester, 20-30 parts of methylhexahydrophthalic anhydride, 10-20 parts of phenol, 200-400 parts of filler, and 0.2-0.5 parts of color paste.

[0039] Epoxy resin, as the base component, provides the backbone structure. Its epoxy groups react with hexahydrophthalic acid bisglycidyl ester, methyl hexahydrophthalic anhydride, and trimethylolpropane triglycidyl ether to significantly increase the material's crosslinking density and structural rigidity, imparting high strength, excellent electrical insulation, and heat resistance. Polypropylene glycol, a flexible segment, enhances the material's toughness, reduces thermal stress during curing, and reduces shrinkage. The addition of polypropylene glycol further enhances crosslinking, significantly improving the material's insulation, thermal stability, and mechanical strength. In this system, the combined use of hexahydrophthalic acid bisglycidyl ester and methyl hexahydrophthalic anhydride curing agents optimizes reaction rate and crosslinking uniformity, resulting in a dense crosslinked structure. Phenol, as an accelerator, accelerates the curing reaction, facilitating rapid curing and molding in subsequent processes. Inorganic fillers improve mechanical strength and enhance insulation properties. Colorants impart color to the outer sleeve.

[0040] The outdoor metal-clad voltage transformer in this embodiment is provided with a metal armor shell 100 outside the voltage transformer. The metal armor shell 100 is made of high-strength, corrosion-resistant metal materials, such as stainless steel or aluminum alloy, to provide solid physical protection, enhance the mechanical strength and electromagnetic shielding performance of the transformer, and effectively resist external electromagnetic interference and mechanical shock. This design can withstand vibrations and shocks during locomotive operation and erosion in harsh outdoor environments, such as high temperature, humidity, salt spray, etc., to ensure its accuracy and reliability. The R-shaped open core 210 is connected in a square shape, which reduces the risk of saturation of the core 210, reduces the no-load loss and no-load current of the core 210, improves the transformer's anti-resonance overvoltage capability, improves the product's load capacity, and improves the performance and stability of the transformer, ensuring its accuracy and reliability. The metal armor shell 100 in the present invention is poured and filled with an insulating filling layer 400, which has a high breakdown voltage and good heat resistance. Commonly used insulating materials include epoxy resin, polyester film, polyimide, etc. These materials not only have good electrical properties, but can also withstand high temperature environments, ensuring the insulation strength and service life of the voltage transformer.

[0041] It will be understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present invention, and the present invention is not limited thereto. Those skilled in the art will appreciate that various modifications and improvements can be made without departing from the spirit and substance of the present invention, and such modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. An outdoor metal-clad voltage transformer for locomotives, characterized in that: It includes a metal armored shell, a coil assembly and an insulating filling layer filled inside the metal armored shell. The coil assembly is arranged in the metal armored shell. The coil assembly includes an iron core, a primary coil and a secondary coil. The secondary coil is sleeved on the iron core, and the primary coil is sleeved on the secondary coil.

2. The outdoor metal-clad voltage transformer for locomotives according to claim 1, characterized in that: The material of the metal armored shell is stainless steel or aluminum alloy.

3. The outdoor metal-clad voltage transformer for locomotive according to claim 1, characterized in that: The iron core is R-shaped, and a square opening is provided in the middle thereof.

4. The outdoor metal-clad voltage transformer for locomotives according to claim 3, characterized in that: An insulating frame is sleeved on the iron core, and the secondary coil is sleeved on the insulating frame.

5. The outdoor metal-clad voltage transformer for locomotive according to claim 4, characterized in that: The interlayer insulation of the primary coil adopts a 1 / 3 lap winding method, and two layers of PMP capacitor composite insulation paper are used between each layer.

6. The outdoor metal-clad voltage transformer for locomotives according to claim 5, characterized in that: An electrostatic screen is also provided outside the primary coil.

7. The outdoor metal-clad voltage transformer for locomotive according to claim 6, characterized in that: The electrostatic screen is provided with a plurality of voltage-equalizing rings.

8. The outdoor metal-clad voltage transformer for locomotive according to claim 1, characterized in that: It also includes a conductor and a connection terminal. The connection terminal is used to connect to the circuit. One end of the conductor is connected to the coil assembly, and the other end is connected to the connection terminal.

9. The outdoor metal-clad voltage transformer for locomotives according to claim 8, characterized in that: Terminal spring contacts are provided on the side walls of the wiring terminal.

10. The outdoor metal-clad voltage transformer for locomotive according to claim 1, characterized in that: It also includes a monitoring component, which includes a controller, a monitoring sensor, and a protection switch. The monitoring sensor and the protection switch are electrically connected to the coil assembly respectively. The monitoring sensor is also electrically connected to the controller, and sends a first signal to the controller when it detects resonance or overvoltage in the coil assembly. The controller is also electrically connected to the protection switch, and controls the protection switch to be disconnected after receiving the first signal.

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