System and method for inhibiting building block type ice melting induced voltage

Abstract

The invention belongs to the technical field of power transmission and distribution, and particularly relates to a system and a method for inhibiting building block type ice melting induced voltage, which are characterized in that the system comprises at least one group of ice melting branch circuit, the ice melting branch circuit comprises two groups of rectifier transformer vehicles and an ice melting valve group device vehicle arranged between the two groups of rectifier transformer vehicles, the ice-melting valve group device vehicle comprises an ice-melting valve group device, the rectifier transformer is electrically connected with the ice-melting valve group device through a non-inductive connecting unit, and during ice melting, a three-phase ice-melting power supply on the power grid side is connected into the rectifier transformer for transformation and then is subjected to alternating-current and direct-current conversion through the ice-melting valve group device; and the direct current output by the ice melting valve group device is applied to a line needing ice melting to carry out ice melting operation. According to the invention, the damage to the secondary equipment caused by the induced voltage generated when the ice melting valve group is unlocked and impacted due to the large stray capacitance and inductance value brought by the cable connection between the rectification transformer vehicle and the ice melting valve group device vehicle is solved, and the safety of operators and background equipment is ensured.

Description

Technical Field

[0001] The present invention relates to an ice melting system, in particular to a system and method for suppressing induced voltage of building block-type ice melting, belonging to the technical field of power transmission and distribution. Background Art

[0002] Traditional mobile ice-melting devices have low utilization rates and small capacity. To improve utilization, flexible, mobile ice-melting devices are connected in parallel to form a modular ice-melting system. The ice-melting valve assembly, during flow unlocking and phase change, causes large voltage and current fluctuations on the valve side, resulting in periodic transient voltage surges (dU / dt). This causes periodic pulse currents to the ground in the primary cable shield between the valve vehicle and the transformer vehicle. The factory-prefabricated grounding wire is long and has a large grounding inductance. The pulse current flowing through the large inductance generates periodic pulsed high voltages on the vehicle body. The secondary power supply of the ice-melting vehicle is connected to the maintenance power box, and the neutral line of the secondary power supply is at a remote low potential. The secondary device housing is connected to the vehicle body. When the vehicle body potential rises, the potential difference between the secondary device housing and the power supply is large.

[0003] Therefore, it is necessary to develop a system for suppressing the induced voltage of building block-type ice melting and its control method to minimize the induced voltage generated by the ice melting equipment to the ground capacitance, which is of great significance to ensure the safety of operators and background equipment. Summary of the Invention

[0004] The purpose of the present invention is to provide a system and method for suppressing the induced voltage of the building block type ice melting, so as to solve the problem of damage to the secondary equipment caused by the induced voltage generated when the ice melting valve group is unlocked due to the large stray capacitance and inductance values ​​brought by the cable connection between the rectifier transformer car and the ice melting valve group device car, thereby ensuring the safety of operators and background equipment.

[0005] To achieve the above objectives, the first technical solution of the present invention is: a modular ice-melting induced voltage suppression system, the innovation of which is that it includes at least one ice-melting branch, which includes a 1# rectifier transformer car, an ice-melting valve assembly vehicle, and a 2# rectifier transformer car, wherein the ice-melting valve assembly vehicle is located between the 1# rectifier transformer car and the 2# rectifier transformer car.

[0006] The 1# rectifier transformer vehicle includes the 1# tractor vehicle and the 1# rectifier transformer mounted on the 1# tractor vehicle.

[0007] The ice melting valve assembly device vehicle comprises an ice melting device vehicle and an ice melting valve assembly device provided on the ice melting device vehicle.

[0008] The 2# rectifier transformer vehicle includes the 2# tractor vehicle and the 2# rectifier transformer mounted on the 2# tractor vehicle.

[0009] The output ends of the 1# rectifier transformer and the 2# rectifier transformer are respectively electrically connected to the AC side of the ice melting valve group device through corresponding non-inductive connection units and with the same phase sequence, so as to suppress the ice melting induced voltage.

[0010] During ice melting, the three-phase ice melting power supply on the grid side is respectively connected to the input ends of the 1# rectifier transformer and the 2# rectifier transformer, and is transformed by the 1# rectifier transformer and the 2# rectifier transformer, and then converted from AC to DC by the ice melting valve group device. The DC current output by the DC side of the ice melting valve group device is output to the line that needs to melt ice to perform ice melting operations.

[0011] In the above-mentioned first technical solution, the non-inductive connection unit includes an output insulating sleeve, a steel-core aluminum stranded wire and a mother pipe. The output ends of the 1# rectifier transformer and the 2# rectifier transformer are respectively electrically connected to one end of the steel-core aluminum stranded wire through the corresponding output insulating sleeve, and the other end of the steel-core aluminum stranded wire is electrically connected to the mother pipe. The mother pipe is electrically connected to the AC side of the ice-melting valve group device through a copper braided wire.

[0012] In the first technical solution, the output end of the 1# rectifier transformer is electrically connected to one end of the steel core aluminum stranded wire through the corresponding output insulating bushing and the transfer copper busbar.

[0013] The two ends of the pipe mother are connected to the composite support insulator arranged on the top of the ice melting valve group device through the pipe mother hardware.

[0014] In the above-mentioned first technical solution, a first climbing frame is provided on the 1# traction vehicle and located outside the 1# rectifier transformer, and the transfer copper bus is connected to the first climbing frame through an insulator. A second climbing frame is provided on the de-icing device vehicle and located outside the de-icing valve group device, and the copper braided wire is fixed to the second climbing frame through an insulator.

[0015] In the first technical solution described above, both ends of the steel core aluminum stranded wire are connected to the transfer copper bus and the tube mother through angle-adjustable hardware.

[0016] In the first technical solution described above, the DC side of the ice-melting valve assembly is connected to a cable, and the DC current is output to the line requiring ice melting through the cable to perform ice melting operations.

[0017] In the first technical solution described above, the input ends of the 1# rectifier transformer and the 2# rectifier transformer are each provided with an insulating input bushing connected to the three-phase ice-melting power supply on the grid side.

[0018] In the above-mentioned first technical solution, the 1# rectifier transformer and the 2# rectifier transformer both adopt forced oil circulation air-cooled oil-immersed transformers, and the 1# rectifier transformer and the 2# rectifier transformer include split-type transformers and insulating oil coolers. The insulating oil outlet and return ports of the transformers are connected to the corresponding connection port pipelines of the insulating oil cooler to form circulating cooling of the insulating oil.

[0019] In the first technical solution described above, the 1# tractor vehicle or the ice-melting device vehicle or the 2# tractor vehicle is further provided with an isolation transformer for supplying secondary power to the ice-melting valve assembly device.

[0020] In the above-mentioned first technical solution, the isolation transformer is a three-phase dry-type double-winding outdoor isolation transformer. The primary side of the isolation transformer is connected to the power supply in the user station, and the secondary side is connected to the aviation plug connection end of the ice melting valve group device through the leakage protection switch. At the same time, the N line of the isolation transformer is connected to the body of the ice melting device vehicle.

[0021] In the first technical solution described above, the control and signal between the ice-melting valve assembly device and the high-voltage switch cabinet are converted and transmitted using a photoelectric isolation device.

[0022] In the first technical solution mentioned above, electrical component grounding collection points are provided on the bodies of the 1# tractor, ice melting device vehicle and 2# tractor, and the ground wires at the grounding collection points of each electrical component are directly connected to the ground grid to ensure the grounding safety of the vehicle body.

[0023] In the above-mentioned first technical solution, a knife switch is connected between the cable on the DC side of the ice-melting valve assembly device and the line that needs to melt ice.

[0024] To achieve the above-mentioned object, the second technical solution of the present invention is: a method for suppressing the induced voltage of building block ice melting, including the above-mentioned system for suppressing the induced voltage of building block ice melting, the innovation of which is that it includes the following steps:

[0025] The three-phase ice-melting power supply on the grid side is connected to the high-voltage side of the 1# rectifier transformer and the 2# rectifier transformer, and the low-voltage side of the 1# rectifier transformer and the 2# rectifier transformer is connected to the AC side of the ice-melting valve group device through a non-inductive connection unit. The DC side of the ice-melting valve group device is connected to the ice-melting line, and the three phases of the ice-melting line are short-circuited. The grounding points of the 1# rectifier transformer car, the ice-melting valve group device car and the 2# rectifier transformer car are directly connected to the ground grid.

[0026] The monitoring background is used to set the parameters of the ice melting system. The control instructions issued by the monitoring background are transmitted to the ice melting valve group device through the photoelectric isolation device, and the 1# rectifier transformer and the 2# rectifier transformer as well as the ice melting valve group device are controlled to make different action responses. The 1# rectifier transformer and the 2# rectifier transformer convert the voltage of the ice melting power supply and convert the AC / DC through the ice melting valve group device.

[0027] According to the connection mode of the ice melting line, the monitoring background controls the rectifier valve group of the ice melting valve group device to work in parallel mode and perform the flow increase unlocking.

[0028] The ice-melting line performs ice-melting operations according to the rising flow rate and ice-melting target current set by the monitoring background.

[0029] In the above second technical solution, the ice melting line is short-circuited in three phases by means of short-circuiting hardware or short-circuiting knife switches.

[0030] In the above second technical solution, the DC side of the ice-melting valve assembly device is connected to the ice-melting circuit through a control knife switch.

[0031] In the above-mentioned second technical solution, the ice-melting line connection mode includes a 1-1 mode or a 1-2 mode. The 1-1 mode adopts a phase-split ice-melting mode, and melts the ice on two phase conductors of the three-phase AC line each time. The 1-2 mode melts the ice on three phase conductors of the three-phase AC line each time.

[0032] The positive effect of the present invention is that after adopting the modular ice-melting induced voltage suppression system and method of the present invention, the system includes at least one ice-melting branch, which includes a 1# rectifier transformer car, an ice-melting valve group device car and a 2# rectifier transformer car, and the ice-melting valve group device car is located between the 1# rectifier transformer car and the 2# rectifier transformer car.

[0033] The 1# rectifier transformer vehicle includes the 1# tractor vehicle and the 1# rectifier transformer mounted on the 1# tractor vehicle.

[0034] The ice melting valve assembly device vehicle comprises an ice melting device vehicle and an ice melting valve assembly device provided on the ice melting device vehicle.

[0035] The 2# rectifier transformer vehicle includes the 2# tractor vehicle and the 2# rectifier transformer mounted on the 2# tractor vehicle.

[0036] The output ends of the 1# rectifier transformer and the 2# rectifier transformer are respectively electrically connected to the AC side of the ice melting valve group device through corresponding non-inductive connection units and with consistent phase sequence, and are used to suppress the ice melting induced voltage.

[0037] In the specific method: the three-phase ice-melting power supply on the grid side is connected to the high-voltage side of the 1# rectifier transformer and the 2# rectifier transformer, and the low-voltage side of the 1# rectifier transformer and the 2# rectifier transformer is connected to the AC side of the ice-melting valve group device through a non-inductive connection unit. The DC side of the ice-melting valve group device is connected to the ice-melting line, and the three phases of the ice-melting line are short-circuited. The grounding points of the 1# rectifier transformer car, the ice-melting valve group device car and the 2# rectifier transformer car are directly connected to the ground grid.

[0038] The monitoring background is used to set the parameters of the ice melting system. The control instructions issued by the monitoring background are transmitted to the ice melting valve group device through the photoelectric isolation device, and the 1# rectifier transformer and the 2# rectifier transformer as well as the ice melting valve group device are controlled to make different action responses. The 1# rectifier transformer and the 2# rectifier transformer convert the voltage of the ice melting power supply and convert the AC / DC through the ice melting valve group device.

[0039] According to the connection mode of the ice melting line, the monitoring background controls the rectifier valve group of the ice melting valve group device to work in parallel mode and perform the flow increase unlocking.

[0040] The ice-melting line performs ice-melting operation according to the rising flow rate and ice-melting target current set by the monitoring background;

[0041] Thus, the present invention can output a DC current many times greater than that of existing ice-melting valve groups, provided that the ice-melting valve group device (rectifier valve group) is the same, thus having a wider range of applications. Furthermore, under the same output parameters of the ice-melting valve group device, the thyristor on-state current can be selected to be less than that of existing ice-melting valve groups, effectively reducing device costs.

[0042] This suppresses transient voltage and current shocks during the unlocking and commutation process of the ice-melting valve group device (thyristor valve group), avoiding the high-frequency regular shock voltage generated by the stray capacitance and ground inductance of the cable connection between the rectifier and ice-melting valve group device car, ensuring the safety of operators and background equipment.

[0043] The utilization rate of the ice melting valve group device is improved, and the convenience and flexibility of the ice melting device during mobile transportation are increased.

[0044] In summary, the present invention can address the problem of stray capacitance accumulation in the modular ice-melting system caused by the need for long-distance cable connections due to the parallel operation of a large number of vehicles, especially the significant voltage rise caused by the distributed capacitance of the cable between the transformer and the ice-melting valve, and the need to specifically suppress the influence of the induced voltage of this section of cable; the present invention effectively reduces the coupling effect of the distributed capacitance of the cable by optimizing the vehicle body connection layout structure and adopting an active compensation method, thereby suppressing the abnormal voltage rise in the key section and improving the system operation stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a structural schematic diagram of a specific embodiment of the present invention;

[0046] Figure 2 This is a cross-sectional view of the AC and DC side inlet and outlet lines of a valve assembly vehicle according to a preferred embodiment of the present invention;

[0047] Figure 3 This is a front view of the 1# rectifier transformer car of the preferred embodiment of the present invention;

[0048] Figure 4This is a front view of an ice melting valve assembly vehicle according to a preferred embodiment of the present invention;

[0049] Figure 5 This is a front view of the 2# rectifier transformer car of the preferred embodiment of the present invention;

[0050] Figure 6 This is a partial view of the conductor connection of the 1# rectifier transformer car in a preferred embodiment of the present invention;

[0051] Figure 7 This is a partial view of the conductor connection of the ice melting valve assembly device according to the preferred embodiment of the present invention;

[0052] Figure 8 Schematic diagram of stray capacitance parameters of field cables and ground wires according to a preferred embodiment of the present invention;

[0053] Figure 9 This is a schematic diagram of external electrical wiring in a preferred embodiment of the present invention;

[0054] Figure 10 is a topological diagram of the electrical principle of a preferred embodiment of the present invention;

[0055] In the figure: 1# rectifier transformer car 1, 1# traction car 11, 1# rectifier transformer 12, first climbing frame 13, ice melting valve group device car 2, ice melting device car 21, ice melting valve group device 22, cable 221, second climbing frame 23, isolation transformer 24, 2# rectifier transformer car 3, 2# traction car 31, 3# rectifier transformer 32, non-inductive connection unit 4, output insulating bushing 41, steel core aluminum stranded wire 42, pipe mother 43, copper braided wire 44, transfer copper bus 45, pipe mother hardware 46, hardware 47, composite post insulator 48, insulating input bushing 5, insulating oil cooler 6, photoelectric isolation device 7. DETAILED DESCRIPTION

[0056] The present invention will be further described below with reference to the accompanying drawings and given embodiments, but the present invention is not limited thereto.

[0057] Example 1

[0058] like Figure 1 、 2 , 3, 4, 5, 6, 7, 8, 9, and 10, a modular ice-melting induced voltage suppression system includes at least one ice-melting branch, which includes a 1# rectifier transformer car 1, an ice-melting valve group device car 2, and a 2# rectifier transformer car 3. The ice-melting valve group device car 2 is located between the 1# rectifier transformer car 1 and the 2# rectifier transformer car 3.

[0059] The 1# rectifier transformer vehicle 1 includes a 1# tractor vehicle 11 and a 1# rectifier transformer 12 mounted on the 1# tractor vehicle 11.

[0060] The ice melting valve assembly vehicle 2 includes an ice melting device vehicle 21 and an ice melting valve assembly device 22 provided on the ice melting device vehicle 21.

[0061] The 2# rectifier transformer vehicle 3 includes a 2# tractor vehicle 31 and a 2# rectifier transformer 32 mounted on the 2# tractor vehicle 31.

[0062] The output ends of the 1# rectifier transformer 12 and the 2# rectifier transformer 32 are respectively electrically connected to the AC side of the ice melting valve assembly 22 through the corresponding non-inductive connection unit 4 and with the same phase sequence, so as to suppress the ice melting induced voltage.

[0063] During ice melting, the three-phase ice melting power supply on the grid side is respectively connected to the input ends of the 1# rectifier transformer 12 and the 2# rectifier transformer 32, and is transformed by the 1# rectifier transformer 12 and the 2# rectifier transformer 32, and then converted from AC to DC by the ice melting valve group device 22. The DC current output from the DC side of the ice melting valve group device 22 is output to the line that needs to melt ice to perform ice melting operations.

[0064] Among them, the 1# tractor and 2# tractor are both quasi-trailer heavy-duty trucks, equipped with anti-skid chains, which can be modified and have a load capacity that meets the requirements of the Ministry of Transport. The overall dimensions of the equipment installation can meet the requirements of the national integrated vehicle announcement for any vehicle model.

[0065] Further, such as Figure 1 、 2 As shown in Figures 3, 4, 5, 6, and 7, to prevent the primary cable shielding layer between the rectifier transformer and the ice-melting valve assembly from presenting periodic pulse current to the ground, the non-inductive connection unit 4 includes an output insulating sleeve 41, a steel-core aluminum stranded wire 42, and a pipe mother 43. The output ends of the 1# rectifier transformer 12 and the 2# rectifier transformer 32 are electrically connected to one end of the steel-core aluminum stranded wire 42 through the corresponding output insulating sleeve 41. The other end of the steel-core aluminum stranded wire 42 is electrically connected to the pipe mother 43. The pipe mother 43 is electrically connected to the AC side of the ice-melting valve assembly 22 through a copper braided wire 44. The present invention achieves electrical connection between the rectifier transformer and the ice-melting valve assembly through a non-inductive connection power supply, eliminating the shielded cable from the transformer low-side to the ice-melting valve assembly AC side in the prior art, minimizing the induced voltage generated by the ice-melting valve assembly capacitance to the ground, and ensuring the safety of operators and background equipment.

[0066] Further, such as Figure 6 As shown, in order to ensure a stable electrical connection between the rectifier transformer and the steel core aluminum stranded wire, the output end of the 1# rectifier transformer 12 is electrically connected to one end of the steel core aluminum stranded wire 42 through the corresponding output insulating sleeve 41 and the transfer copper bus 45.

[0067] In order to provide good support and insulation, and to prevent the ice-melting valve assembly from being too high, the two ends of the pipe mother 43 are connected to the composite support insulator 48 provided on the top of the ice-melting valve assembly 22 through the pipe mother hardware 46. The composite support insulator 48 can also be easily disassembled and repaired.

[0068] Further, if Figure 1 As shown, in order to facilitate the adjustment of the phase sequence on the low-voltage side of the rectifier transformer and ensure that the phase sequence of the 1# rectifier transformer and the 2# rectifier transformer are connected to the ice-melting valve group device in the same manner, a first climbing frame 13 is provided on the 1# tractor 11 and located on the outside of the 1# rectifier transformer 12, and the transfer copper bus 45 is connected to the first climbing frame 13 through an insulator. A second climbing frame 23 is provided on the ice-melting device vehicle 21 and located on the outside of the ice-melting valve group device 22, and the copper braided wire 44 is fixed to the second climbing frame 23 through an insulator.

[0069] Furthermore, in order to facilitate quick and efficient installation, the first climbing frame 13 is fixed to the vehicle plate of the 1# tractor 11 by bolts, the insulator is fixed to the first climbing frame 13 by bolts, and the transfer copper bus 45 is fixed to the insulator by bolts for electrical insulation support.

[0070] Further, such as Figure 3 、 4 As shown in Figures 6 and 7, in order to facilitate repeated disassembly, installation and use, the two ends of the steel core aluminum stranded wire 42 are connected to the transfer copper bus 45 and the tube mother 43 through angle-adjustable hardware 47. The hardware 47 can be adjusted from 0° to 90° to adapt to the connection direction of the steel core aluminum stranded wire and fix it. It can be disassembled and transported when it is needed to melt ice in different places.

[0071] Specifically, one end of the steel core aluminum stranded wire 42 is fixed to one end of the transfer copper busbar 45 by a zero-degree wire clamp with a bolt, and the other end of the transfer copper busbar 45 is connected to the output insulating sleeve 41 of the 1# rectifier transformer 12 by a bolt to carry current;

[0072] The other end of the steel core aluminum stranded wire 42 is fixed to the mother pipe 43 through a 30° wire clamp hardware and fastened by bolts. The mother pipe 43 is fixed to the composite support insulator 48 through the mother pipe hardware 46 and fastened by bolts. The composite support insulator 48 is fixed to the top of the container of the ice melting valve group device 22 and is detachably connected by bolts.

[0073] Further, such as Figure 1 、 4 As shown, in order to facilitate quick connection with the ice-melting line and realize DC access, the DC side of the ice-melting valve group device 22 is connected to a cable 221, and the DC current is output to the line requiring ice melting through the cable 221 to perform ice melting operations.

[0074] Further, such as Figure 1 、 3 As shown in Figures 5 and 6, in order to ensure the safe access of the three-phase ice-melting power supply to the rectifier transformer, the input ends of the 1# rectifier transformer 12 and the 2# rectifier transformer 32 are each provided with an insulating input bushing 5 connected to the three-phase ice-melting power supply on the grid side.

[0075] Further, such as Figure 1 、 3 As shown in Figures 5 and 6, in order to significantly reduce the weight and volume of the rectifier transformers, so that the vehicle-mounted weight and volume can be reduced accordingly, the 1# rectifier transformer 12 and the 2# rectifier transformer 32 both adopt forced oil circulation air-cooled oil-immersed transformers for voltage conversion, which work by converting the high voltage received by the primary winding into a low voltage suitable for different purposes, or vice versa. The 1# rectifier transformer 12 and the 2# rectifier transformer 32 include a split-type transformer and an insulating oil cooler 6. The insulating oil outlet and return ports of the transformers are connected to the corresponding connection port pipelines of the insulating oil cooler 6 to form a circulating cooling of the insulating oil, that is, the coils of the transformers are immersed in the insulating oil. The oil not only helps to improve the electrical insulation performance, but also has good heat dissipation performance, which can effectively take away the heat generated during the operation of the transformer.

[0076] Further, such as Figure 1 、 5 As shown in Figures 9 and 9, after adopting voltage isolation measures, the voltage rise of the vehicle will be greatly improved, but it is inevitable that there will still be a certain potential. Therefore, in order to ensure the safety of secondary equipment and operators, the power supply scheme is optimized. The 1# tractor 11 or the ice melting device vehicle 21 or the 2# tractor 31 is also provided with an isolation transformer 24 for supplying secondary power to the ice melting valve group device 22, and the isolation transformer 24 is fixed to the corresponding vehicle body by bolts to supply the secondary power to the ice melting valve group device.

[0077] Since the original power supply scheme is to directly introduce the power into the ice-melting valve group device through cables at locations such as the station maintenance power box, and the power supply method on site is uncertain, the potential between the high voltage of the ice-melting valve group device and the N line is relatively high. Therefore, the present invention adds an isolation transformer.

[0078] Specifically, the isolation transformer 24 is a three-phase dry-type double-winding outdoor isolation transformer. The primary side of the isolation transformer 24 is connected to the power supply in the user station, and the secondary side is connected to the aviation plug connection end of the ice melting valve group device 22 through the leakage protection switch. At the same time, the N line of the isolation transformer 24 is connected to the body of the ice melting device vehicle 21, which greatly improves the safety of the secondary equipment operation.

[0079] Further, such as Figure 10As shown, in order to avoid the influence of high potential, the control and signal between the ice-melting valve group device 22 and the high-voltage switch cabinet are converted and transmitted using a photoelectric isolation device 7 to achieve secondary signal electrical isolation, and the photoelectric isolation device 7 is arranged in the user's operating room. In this way, the control and signal between the high-voltage switch cabinet and the ice-melting valve group device are isolated by optical fiber, which effectively avoids the influence of high potential and ensures the safe operation of operators and background equipment.

[0080] According to the test, the length and winding placement of the existing grounding wire make the induced voltage effect generated by the inductance non-negligible. Therefore, it is necessary to optimize the grounding wire wiring method. Specifically, the vehicle bodies of the 1# tractor 11, the ice melting device vehicle 21 and the 2# tractor 31 are all provided with electrical component grounding collection points, and the ground wires at the grounding collection points of each electrical component are directly connected to the ground grid to achieve the grounding safety of the vehicle body and avoid the single vehicle grounding cable being too long, which causes excessive voltage.

[0081] Specifically, in actual application scenarios, special yellow-green grounding wires are used to make grounding wires of different lengths. The length is as short as possible and connected to the ground grid nearby. They are not entangled or coiled. Direct single-point grounding is used to avoid the grounding cable of a single vehicle being too long, entangled, or coiled, which may cause the induced voltage to be too high. That is, each vehicle on site uses two grounding wires of appropriate length to connect in parallel for grounding; if the length is not enough, the grounding wire of appropriate length can be remade by the on-site pressure head, and the grounding wire cannot be entangled or coiled when connected.

[0082] Furthermore, in order to facilitate the control of ice melting lines, such as Figure 10 As shown, a knife switch is connected between the cable 221 on the DC side of the ice-melting valve assembly 22 and the line that needs to melt ice.

[0083] Furthermore, in order to explain the reason for the generation of induced voltage, Figure 8 It can be seen that during the operation of the ice-melting device, the thyristor valve group is subjected to severe transient voltage and current surges during the unlocking and commutation phases. This dynamic process induces high-frequency, regularly varying surge voltages in the capacitance of the device's cables to ground and the inductance of the ground wire to ground. Given the large capacitance and inductance parameters, the resulting induced voltage peaks far exceed the normal operating range, causing a series of destructive consequences such as insulation damage and signal interference, seriously threatening the safe and stable operation of the ice-melting device. Therefore, measures to suppress the induced voltage are essential.

[0084] like Figure 10 As shown, the topology of the actual application scenario can be configured by connecting multiple groups of ice-melting branches in parallel. Under the condition that the rectifier valve group is the same, the DC current output can be many times that of the existing ice-melting device, which has a wider range of applications. Under the condition that the output parameters of the ice-melting device are the same, the thyristor on-state current can be less than that of the existing ice-melting device, which effectively reduces the device cost.

[0085] In summary, the present invention can address the problem of stray capacitance accumulation in the modular ice-melting system caused by the need to use long-distance cable connections due to the parallel operation of a large number of vehicles, especially the significant voltage rise caused by the distributed capacitance of the cable between the transformer and the ice-melting valve, and the need to specifically suppress the influence of the induced voltage of this section of cable; the present invention effectively reduces the coupling effect of the distributed capacitance of the cable by optimizing the vehicle body connection layout structure and adopting an active compensation method, thereby suppressing the abnormal voltage rise in the key section and improving the system operation stability.

[0086] Example 2

[0087] like Figure 1 、 9 As shown in FIG10 , a method for suppressing induced voltage of building block ice melting includes the above-mentioned system for suppressing induced voltage of building block ice melting, including the following steps:

[0088] (1) Preliminary preparation process

[0089] The low-voltage sides of the 1# rectifier transformer 12 and the 2# rectifier transformer 32 are pre-connected to the AC side of the ice-melting valve group device 22 through a non-inductive connection unit. The three-phase ice-melting power supply on the grid side is connected to the high-voltage side of the 1# rectifier transformer 12 and the 2# rectifier transformer 32 through the corresponding insulating input bushing 5. The DC side of the ice-melting valve group device 22 is connected to the ice-melting line through a control knife switch. The secondary power supply of the high-voltage switchgear in the operation monitoring background provides secondary power supply to the ice-melting valve group device 22 through the isolation transformer 24. The control and signal of the high-voltage switchgear are connected to the ice-melting valve group device 22 through the photoelectric isolation device 7.

[0090] 1# rectifier transformer car 1, ice melting valve group device car 2 and 2# rectifier transformer car 3 are all directly connected to the ground grid nearby, and ensure that the grounding wires are not entangled or coiled.

[0091] The de-icing line is in the middle or opposite station, and the three phases are short-circuited by using the corresponding short-circuiting hardware or short-circuiting knife switch.

[0092] Use the monitoring background to set the ice melting system parameters,

[0093] (2) Ice melting operations

[0094] The control (start) command issued by the monitoring background is transmitted to the ice-melting valve group device 22 through the photoelectric isolation device to achieve network electrical isolation and control the 1# rectifier transformer 12, the 2# rectifier transformer 32 and the ice-melting valve group device 22 to make different action responses. The 1# rectifier transformer 12 and the 2# rectifier transformer 32 convert the ice-melting power supply voltage and convert it into AC / DC through the ice-melting valve group device 22.

[0095] According to the connection mode of the ice melting circuit on the DC side of the ice melting valve group device, the two 6-pulse ice melting systems operate their respective 6 DC isolation switches to connect the ice melting device and the ice melting circuit.

[0096] Up-flow unlocking: According to the connection mode of the ice-melting line, the monitoring background controls the rectifier valve group of the ice-melting valve group device 22 to work in parallel mode, controls different DC isolation switches to close and open, and performs up-flow unlocking.

[0097] The ice-melting line performs ice-melting operations according to the rising flow rate and ice-melting target current set by the monitoring background.

[0098] Furthermore, the ice-melting current value, ice-melting mode and ice-melting phase sequence are confirmed in advance according to the ice-covering condition of the line. The ice-melting line connection mode includes a 1-1 mode or a 1-2 mode.

[0099] For short distances and when ice thickness is severe, a phase-split ice melting mode is used. Two phases of the three-phase AC line are melted each time. The three phases at the opposite end are short-circuited, one phase at this end is connected to the positive pole of the DC voltage of the ice melting device, and the other phase is connected to the negative pole of the DC voltage of the ice melting device to melt the ice. This is usually called the "1-1 mode."

[0100] For long distances and light ice coverage, the three phases of a three-phase AC line are melted one at a time. The three phases at the opposite end are short-circuited, and one phase at the local end is connected to the positive DC voltage of the ice-melting device. The other two phases are connected in parallel and then to the negative DC voltage of the ice-melting device (equivalent to a parallel circuit with low resistance and long ice-melting distance). This is commonly referred to as the "1-2 mode."

[0101] In summary, the present invention suppresses the ice melting induced voltage through the following innovative methods:

[0102] ①By optimizing the overall layout structure and achieving electrical connection through bare conductors,

[0103] ② Grounding wire optimization,

[0104] ③Optimization of power supply mode,

[0105] ④ Structural optimization of control and signal power supply optoelectronic isolation.

[0106] Thus, the present invention can output a DC current many times greater than that of existing ice-melting valve groups, provided that the ice-melting valve group device (rectifier valve group) is the same, thus having a wider range of applications. Furthermore, under the same output parameters of the ice-melting valve group device, the thyristor on-state current can be selected to be less than that of existing ice-melting valve groups, effectively reducing device costs.

[0107] It suppresses transient voltage and current shocks during the unlocking and commutation process of the ice melting valve group device (thyristor valve group), avoids the high-frequency regular shock voltage generated by the cable-to-ground capacitance and ground wire-to-ground inductance of the entire device, and ensures the safety of operators and background equipment;

[0108] The utilization rate of the ice melting valve group device is improved, and the convenience and flexibility of the ice melting device during mobile transportation are increased.

[0109] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A system for suppressing induced voltage during ice melting, characterized by: The invention comprises at least one group of ice-melting branches, wherein the ice-melting branches include a 1# rectifier transformer car (1), an ice-melting valve group device car (2) and a 2# rectifier transformer car (3), wherein the ice-melting valve group device car (2) is located between the 1# rectifier transformer car (1) and the 2# rectifier transformer car (3). The 1# rectifier transformer vehicle (1) comprises a 1# tractor vehicle (11) and a 1# rectifier transformer (12) mounted on the 1# tractor vehicle (11). The ice-melting valve assembly device vehicle (2) comprises an ice-melting device vehicle (21) and an ice-melting valve assembly device (22) provided on the ice-melting device vehicle (21). The 2# rectifier transformer vehicle (3) comprises a 2# tractor vehicle (31) and a 2# rectifier transformer (32) mounted on the 2# tractor vehicle (31). The output ends of the 1# rectifier transformer (12) and the 2# rectifier transformer (32) are respectively electrically connected to the AC side of the ice-melting valve assembly device (22) through corresponding non-inductive connection units (4) and with consistent phase sequence, so as to suppress the ice-melting induced voltage. During ice melting, the three-phase ice melting power supply on the grid side is respectively connected to the input ends of the first rectifier transformer (12) and the second rectifier transformer (32), and the voltage is transformed by the first rectifier transformer (12) and the second rectifier transformer (32), and then the AC-DC conversion is performed by the ice melting valve group device (22). The DC current outputted from the DC side of the ice melting valve group device (22) is outputted to the line requiring ice melting to perform the ice melting operation.

2. The system for suppressing induced voltage of building block ice melting according to claim 1, characterized in that: The non-inductive connection unit (4) comprises an output insulating sleeve (41), a steel core aluminum stranded wire (42) and a mother pipe (43); the output ends of the 1# rectifier transformer (12) and the 2# rectifier transformer (32) are electrically connected to one end of the steel core aluminum stranded wire (42) through the corresponding output insulating sleeve (41); the other end of the steel core aluminum stranded wire (42) is electrically connected to the mother pipe (43); and the mother pipe (43) is electrically connected to the AC side of the ice melting valve assembly device (22) through a copper braided wire (44).

3. The system for suppressing induced voltage of building block ice melting according to claim 2, characterized in that: The output end of the 1# rectifier transformer (12) is electrically connected to one end of the steel core aluminum stranded wire (42) through the corresponding output insulating sleeve (41) and the transfer copper busbar (45). Both ends of the tube mother (43) are connected to a composite support insulator (48) provided on the top of the ice melting valve assembly device (22) through a tube mother metal fitting (46).

4. The system for suppressing induced voltage of building block ice melting according to claim 3, characterized in that: A first climbing frame (13) is provided on the No. 1 tractor vehicle (11) and is located outside the No. 1 rectifier transformer (12); the transfer copper busbar (45) is connected to the first climbing frame (13) via an insulator; a second climbing frame (23) is provided on the de-icing device vehicle (21) and is located outside the de-icing valve assembly device (22); and the copper braided wire (44) is fixed to the second climbing frame (23) via an insulator.

5. The system for suppressing induced voltage of building block ice melting according to claim 3, characterized in that: The two ends of the steel core aluminum stranded wire (42) are respectively connected to the transfer copper bus (45) and the tube mother (43) through angle-adjustable metal fittings (47).

6. The system for suppressing induced voltage of building block ice melting according to claim 1, characterized in that: The DC side of the ice-melting valve assembly device (22) is connected to a cable (221), and the DC current is output to the circuit requiring ice melting through the cable (221) to perform ice melting operations.

7. The system for suppressing induced voltage of building block ice melting according to claim 1, characterized in that: The input ends of the 1# rectifier transformer (12) and the 2# rectifier transformer (32) are respectively provided with insulating input bushings (5) connected to the three-phase ice-melting power supply on the grid side.

8. The system for suppressing induced voltage of building block ice melting according to claim 1, characterized in that: The 1# rectifier transformer (12) and the 2# rectifier transformer (32) are both forced oil circulation air-cooled oil-immersed transformers, and the 1# rectifier transformer (12) and the 2# rectifier transformer (32) include a transformer and an insulating oil cooler (6) arranged in a split manner, and the insulating oil outlet and return ports of the transformers are connected to the corresponding connecting port pipelines of the insulating oil cooler (6) to form circulating cooling of the insulating oil.

9. The system for suppressing induced voltage of building block ice melting according to claim 1, characterized in that: The 1# tractor (11) or the ice-melting device vehicle (21) or the 2# tractor (31) is also provided with an isolation transformer (24) for supplying secondary power to the ice-melting valve assembly device (22).

10. The system for suppressing induced voltage of building block ice melting according to claim 9, characterized in that: The isolation transformer (24) is a three-phase dry-type double-winding outdoor isolation transformer. The primary side of the isolation transformer (24) is connected to the power supply in the user station, and the secondary side is connected to the aviation plug connection end of the ice melting valve assembly device (22) through a leakage protection switch. At the same time, the N line of the isolation transformer (24) is connected to the body of the ice melting device vehicle (21).

11. The system for suppressing induced voltage of building block ice melting according to claim 1, characterized in that: The control and signal between the ice-melting valve assembly device (22) and the high-voltage switch cabinet are converted and transmitted using a photoelectric isolation device (7).

12. The system for suppressing induced voltage of building block ice melting according to claim 1, characterized in that: The bodies of the 1# tractor (11), the ice melting device vehicle (21) and the 2# tractor (31) are all provided with electrical component grounding aggregation points, and the ground wires at the electrical component grounding aggregation points are directly connected to the ground grid to achieve grounding safety of the vehicle bodies.

13. The system for suppressing induced voltage of building block ice melting according to claim 1, characterized in that: A knife switch is connected between the cable (221) on the DC side of the ice-melting valve assembly device (22) and the circuit requiring ice melting.

14. A method for suppressing induced voltage in block-type ice melting, comprising the system for suppressing induced voltage in block-type ice melting according to any one of claims 1 to 13, characterized in that: The following steps are involved: The three-phase ice-melting power supply on the grid side is connected to the high-voltage side of the 1# rectifier transformer (12) and the 2# rectifier transformer (32), and the low-voltage side of each of the 1# rectifier transformer (12) and the 2# rectifier transformer (32) is connected to the AC side of the ice-melting valve group device (22) through a non-inductive connection unit. The DC side of the ice-melting valve group device (22) is connected to the ice-melting line, and the three phases of the ice-melting line are short-circuited. The grounding points of the 1# rectifier transformer car (1), the ice-melting valve group device car (2) and the 2# rectifier transformer car (3) are directly connected to the ground grid. The monitoring background is used to set the parameters of the ice melting system. The control instructions issued by the monitoring background are transmitted to the ice melting valve group device (22) through the photoelectric isolation device, and the 1# rectifier transformer (12) and the 2# rectifier transformer (32) and the ice melting valve group device (22) are controlled to make different action responses. The 1# rectifier transformer (12) and the 2# rectifier transformer (32) convert the voltage of the ice melting power supply and convert the AC to DC through the ice melting valve group device (22). According to the connection mode of the ice melting line, the monitoring background controls the rectifier valve group of the ice melting valve group device (22) to work in parallel mode and performs flow increase unlocking. The ice-melting line performs ice-melting operations according to the rising flow rate and ice-melting target current set by the monitoring background.

15. The method for suppressing induced voltage in building block ice melting according to claim 14, characterized in that: The ice melting line is short-circuited in three phases by means of a short-circuiting fitting or a short-circuiting knife switch.

16. The method for suppressing induced voltage in building block ice melting according to claim 14, characterized in that: The DC side of the ice-melting valve assembly device (22) is connected to the ice-melting circuit via a control switch.

17. The method for suppressing induced voltage in building block ice melting according to claim 14, characterized in that: The ice-melting line connection mode includes a 1-1 mode or a 1-2 mode. The 1-1 mode adopts a phase-split ice-melting mode, and ice is melted on two phase conductors of a three-phase AC line each time. The 1-2 mode melts ice on three phase conductors of a three-phase AC line each time.

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