Ice melting device and method

Abstract

The invention discloses an ice melting device and method. The device comprises a rectification module, an ice melting mode selection module, a DC-DC module and an inversion module. The input end of the rectifier module is connected with the bus, the output end of the rectifier module is connected with the ice melting mode selection module, and the rectifier module takes electricity from the bus and converts alternating current into direct current; the ice melting mode selection module is connected with the input end of the DC-DC module and the input end of the inversion module, and the ice melting mode selection module selects the DC-DC module to melt ice or selects the inversion module to melt ice according to an ice melting line; the DC-DC module is connected in parallel with the inverter module, and the DC-DC module performs ice melting output according to the direct current output by the rectifier module; the inversion module converts the direct current output by the rectification module into alternating current and then carries out ice melting output. According to the technical scheme, the ice melting mode can be selected according to the line condition, the reliability, stability and ice melting efficiency of line ice melting are improved, and a safety guarantee is provided for stable operation of a power distribution network.

Description

Technical Field

[0001] The present invention relates to the technical field of ice melting of distribution network lines, and in particular to an ice melting device and method. Background Art

[0002] In recent years, the occurrence of extreme weather has had a great impact on the power system. Among them, the transmission lines are increasingly covered with ice. The icing disaster of power lines seriously threatens the safe, reliable and stable operation of the power system.

[0003] Since the transmission network is often exposed to the open air, it is often very vulnerable to natural disasters, which may cause accidents in the transmission network. The distribution network line is at the end of the power supply system, and its power protection is particularly important. Increasing the DC or AC charge of the transmission line will produce a thermal effect and use the heat to melt the ice. However, in actual ice melting, different ice melting lines have different requirements. DC ice melting and AC ice melting have their own advantages and disadvantages. DC ice melting melts the ice on the entire line, which consumes a lot of energy and is easy to produce harmonics in actual applications. The critical short-circuit current of DC ice melting is larger than that of AC ice melting, and the ice melting time is slow. Since the reactance of the high-voltage AC line is much greater than the resistance, the power capacity required for AC ice melting is much greater than that of DC ice melting, and AC ice melting is difficult to apply in actual applications on long lines. Summary of the invention

[0004] The invention provides an ice melting device and method to solve the ice melting problem of ice-covered lines in a distribution network.

[0005] According to one aspect of the present invention, there is provided an ice melting device, comprising: a rectifier module, an ice melting mode selection module, a DC-DC module and an inverter module;

[0006] The input end of the rectifier module is connected to the bus, the output end of the rectifier module is connected to the ice melting mode selection module, and the rectifier module is used to take power from the bus and convert AC power into DC power;

[0007] The ice-melting mode selection module is connected to the input end of the DC-DC module and the input end of the inverter module, and the ice-melting mode selection module is used to select the DC-DC module to melt ice or select the inverter module to melt ice according to the ice-melting line;

[0008] The DC-DC module is connected in parallel with the inverter module, and the DC-DC module is used to output ice melting according to the direct current output by the rectifier module; the inverter module is used to convert the direct current output by the rectifier module into alternating current and then output ice melting.

[0009] Optionally, the DC-DC module is used to convert the direct current output by the rectifier module into a voltage value required for melting ice in the ice-melting circuit.

[0010] Optionally, the inverter module adopts a full-bridge inverter, and the full-bridge inverter is used to convert direct current into alternating current and then output it for ice melting.

[0011] Optionally, the full-bridge inverter includes an inverter circuit, a logic circuit, and a filter circuit;

[0012] The inverter circuit is used to convert direct current into alternating current; the logic circuit is used to generate a control signal to control the inverter circuit; and the filter circuit is used to filter out unnecessary signals.

[0013] Optionally, the ice melting mode selection module includes a control module and two-way switches;

[0014] The control module is used to control the switching of two-way switches;

[0015] The two-way knife switches are connected to the output end of the rectifier module, the input end of the DC-DC module, and the input end of the inverter module. The control module is used to control one of the two-way knife switches to connect the output end of the rectifier module with the input end of the DC-DC module to switch the ice melting mode to DC ice melting, or control the other of the two-way knife switches to connect the output end of the rectifier module with the input end of the inverter module to switch the ice melting mode to AC ice melting.

[0016] Optionally, the two-way knife switches are remotely controlled switches, and one of the two-way knife switches is interlocked with the other.

[0017] Optionally, the rectifier module includes a power quality management unit, and the power quality management unit is used to isolate the harmonic pollution caused by the DC-DC module and the inverter module to the power grid.

[0018] Optionally, in the power distribution line, the first section of the ice-melting line is connected to the output end of the ice-melting device, and the end of the ice-melting line is connected to the ice-melting short-circuit device.

[0019] According to another aspect of the present invention, there is provided an ice melting method, which is performed by using the ice melting device according to any embodiment of the present invention, and the ice melting method comprises:

[0020] Controlling the isolation switch to segment the ice-melting line and disconnect the power supply of the ice-melting line;

[0021] Opening the ice-melting short-circuiting device at the end of the ice-melting line to short-circuit the ice-melting line;

[0022] The ice melting device is connected in series between the bus and the ice melting line, wherein the input end of the rectifier module is connected to the bus, and the output end of the DC-DC module and the output end of the inverter module are connected to the ice melting line;

[0023] Selecting a corresponding ice melting mode according to the ice melting line conditions;

[0024] The ice melting device is started to melt ice.

[0025] Optionally, after starting the ice melting device to melt ice, the method further includes:

[0026] Adjust the ice-melting voltage to melt the ice on the line;

[0027] After the ice is melted, the connection between the ice-melting device and the busbar and the ice-melting line is disconnected, and the power supply of the ice-melting line is restored.

[0028] The technical solution of the embodiment of the present invention is to set a rectifier module, an ice-melting mode selection module, a DC-DC module and an inverter module, take power from the bus according to the rectifier module, and convert the AC power into DC power for power supply. The ice-melting mode selection module selects DC ice-melting or AC ice-melting according to the specific situation of the ice-melting line. After determining the ice-melting mode, the DC-DC module is used to convert the DC output of the rectifier module into the DC voltage value required by the ice-melting line, or the inverter module is used to convert the DC output of the rectifier module into the AC voltage value required by the ice-melting line before melting the ice. The technical solution of the embodiment of the present invention can select the ice-melting mode according to the specific situation of the ice-covered line, improve the reliability, stability and ice-melting efficiency of the line ice-melting, and provide safety guarantee for the stable operation of the distribution network.

[0029] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 is a structural schematic diagram of an ice melting device provided according to an embodiment of the present invention;

[0032] Figure 2 is a flow chart of an ice melting method provided according to an embodiment of the present invention;

[0033] Figure 3 The diagram is a schematic diagram of connecting an ice melting device when an ice melting line is melted according to an embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0035] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0036] Figure 1 The present invention provides a schematic diagram of the structure of an ice melting device. This embodiment is applicable to the ice melting of distribution network lines. The ice melting device can be implemented in the form of hardware and / or software, and the device can be configured in the distribution network lines. Figure 1 As shown, the device includes: a rectifier module 101, an ice melting mode selection module 102, a DC-DC module 103 and an inverter module 104;

[0037] The input end of the rectifier module 101 is connected to the bus, and the output end of the rectifier module 101 is connected to the ice melting mode selection module 102. The rectifier module 101 is used to take power from the bus and convert AC power into DC power.

[0038] The ice-melting mode selection module 102 is connected to the input end of the DC-DC module 103 and the input end of the inverter module 104. The ice-melting mode selection module 102 is used to select the DC-DC module 103 to melt ice or select the inverter module 104 to melt ice according to the ice-melting line;

[0039] The DC-DC module 103 is connected in parallel with the inverter module 104. The DC-DC module 103 is used to melt ice according to the DC power output by the rectifier module 102. The inverter module 104 is used to convert the DC power output by the rectifier module 102 into AC power for melting ice.

[0040] Among them, the input end of the rectifier module 101 is connected to the busbar, and the rectifier module 101 can draw power from the busbar and convert AC power into DC power for use by the back-end module. The busbar can be a 10k busbar. The ice melting mode selection module 102 can select the ice melting mode as DC ice melting or AC ice melting according to the specific situation of the ice melting line. The specific situation of the ice melting line includes the specific parameters of the line, the grid conditions, the availability and economy of the ice melting device. DC ice melting is to apply DC current to the ice-covered line, use the ice-covered line as a load, and use the DC current generated by a lower voltage to melt the ice on the line. AC ice melting mainly melts the ice on the line by using the Joule heat generated by the AC current passing through the conductor. DC ice melting can be selected when the ice melting line is long, and AC ice melting can be selected when the main line ice melting line has many branches. The DC-DC module 103 is connected in parallel with the inverter module 104, and the input end is connected to the ice-melting mode selection module 102. The DC-DC module 103 can convert the direct current output by the rectifier module 101 into a direct current voltage value required by the ice-melting circuit. The specific output ice-melting voltage value is set according to the specific conditions of the ice-melting circuit. The inverter module 104 can convert the direct current output by the rectifier module 102 into an alternating current voltage value required by the ice-melting circuit for ice-melting.

[0041] The technical solution of the embodiment of the present invention is to set a rectifier module, an ice-melting mode selection module, a DC-DC module and an inverter module, take power from the bus according to the rectifier module, and convert the AC power into DC power for power supply. The ice-melting mode selection module selects DC ice-melting or AC ice-melting according to the specific situation of the ice-melting line. After determining the ice-melting mode, the DC-DC module is used to convert the DC output of the rectifier module into the DC voltage value required by the ice-melting line, or the inverter module is used to convert the DC output of the rectifier module into the AC voltage value required by the ice-melting line before melting the ice. The technical solution of the embodiment of the present invention can select the ice-melting mode according to the specific situation of the ice-covered line, improve the reliability, stability and ice-melting efficiency of the line ice-melting, and provide safety guarantee for the stable operation of the distribution network.

[0042] In some optional embodiments of the embodiments of the present invention, the DC-DC module is used to convert the direct current output by the rectifier module into a voltage value required for melting ice in the ice-melting circuit.

[0043] According to the specific requirements of the ice-melting line, the output DC voltage is adjusted to meet the specific requirements for voltage during the ice-melting process. In practical applications, the required voltage value needs to be determined based on the specific parameters of the ice-melting line and the ice-melting device.

[0044] In some optional embodiments of the embodiments of the present invention, the inverter module adopts a full-bridge inverter, and the full-bridge inverter is used to convert direct current into alternating current and then output it for ice melting.

[0045] Among them, the full-bridge inverter is mainly a device that converts direct current (DC) into alternating current (AC). The basic working principle of the full-bridge inverter is to convert the DC power supply into alternating current with the required frequency, amplitude and phase, such as low-frequency alternating current, by controlling the conduction and shutdown of four switching tubes (usually IGBT or MOSFET).

[0046] In some optional embodiments of the present invention, the full-bridge inverter includes an inverter circuit, a logic circuit, and a filter circuit;

[0047] The inverter circuit is used to convert direct current into alternating current; the logic circuit is used to generate control signals to control the inverter circuit; and the filter circuit is used to filter out unnecessary signals.

[0048] Among them, the inverter circuit converts direct current (DC) into alternating current (AC). The full-bridge inverter circuit consists of four switching devices (usually MOSFET or IGBT) to form a full-bridge structure. By controlling the on and off of the four switching devices, the conversion of DC to AC can be achieved. The logic circuit is responsible for generating control signals to control the switching devices in the inverter circuit. Usually based on pulse width modulation (PWM) technology, the frequency and voltage of the output AC can be controlled by adjusting the on time of the switching device. The function of the filter circuit is to filter out unnecessary signals, reduce harmonics, and improve the quality of power.

[0049] In some optional embodiments of the present invention, the ice melting mode selection module includes a control module and a two-way knife switch;

[0050] The control module is used to control the switching of two-way switches;

[0051] The two-way knife switch is connected to the output end of the rectifier module, the input end of the DC-DC module, and the input end of the inverter module. The control module is used to control one of the two-way knife switch to connect the output end of the rectifier module with the input end of the DC-DC module to switch the ice melting mode to DC ice melting, or control the other of the two-way knife switch to connect the output end of the rectifier module with the input end of the inverter module to switch the ice melting mode to AC ice melting.

[0052] The control module connects the rectifier module with the DC-DC module by controlling one of the two switches, and selects DC ice melting. Or the control module connects the rectifier module with the inverter module by controlling the other of the two switches, and selects AC ice melting.

[0053] In some optional embodiments of the embodiments of the present invention, the two-way knife switch is a remote-controlled switch, and one of the two-way knife switches is interlocked with the other.

[0054] Among them, the two-way knife switch can remotely control two independent paths, namely the DC-DC module or the inverter module, that is, the control module can select the ice melting mode by controlling the two-way knife switch, whether it is DC ice melting or AC ice melting. Interlocking one of the two-way knife switches with the other means that only one knife switch can be in the closed state, while the other knife switch is locked in the open state, and vice versa.

[0055] In some optional embodiments of the embodiments of the present invention, the rectifier module includes a power quality management unit, and the power quality management unit is used to isolate the harmonic pollution caused by the DC-DC module and the inverter module to the power grid.

[0056] Among them, DC-DC modules and inverter modules will generate harmonics during operation, which will pollute the power grid, affect the stability and power quality of the power grid, and also damage the equipment in the power grid. The power quality management unit can isolate the harmonic pollution caused by DC-DC modules and inverter modules to the power grid, ensuring the safety and reliability of power system operation.

[0057] In some optional embodiments of the embodiments of the present invention, in the power distribution line, the first section of the ice-melting line is connected to the output end of the ice-melting device, and the end of the ice-melting line is connected to the ice-melting short-circuit device.

[0058] Among them, the ice-melting short-circuiting device can short-circuit one end of the line in the transmission line that needs to melt the ice, and the branch line on the main line is in an open circuit state, ensuring that the current passes through the line that needs to melt the ice and avoid current dispersion, thereby speeding up the ice melting speed and improving the ice melting efficiency.

[0059] Figure 2 A flow chart of an ice melting method provided in an embodiment of the present invention. Figure 3 1 is a schematic diagram of the connection of an ice melting device when melting ice on an ice melting line provided in an embodiment of the present invention. The ice melting method can be performed by the ice melting device described in the above embodiment. Figure 2 and Figure 3 , the method comprising:

[0060] S201, control the isolation switch to segment the ice-melting line and disconnect the power supply of the ice-melting line.

[0061] The ice-melting line can be segmented by the isolation switch 302, and the power supply of the ice-melting line can be disconnected by the third switch S3 to ensure the safety of operators and equipment, while ensuring the efficiency of ice-melting operation and the stability of the power grid.

[0062] S202: Turn on the ice-melting short-circuiting device at the end of the ice-melting line to short-circuit the ice-melting line.

[0063] Among them, the ice-melting short-circuit device 305 can short-circuit one end of the ice-melting line, and the branch line 304 is in an open circuit state, which can ensure that the current passes through the line that needs to be melted and avoid current dispersion, thereby accelerating the ice-melting speed and improving the ice-melting efficiency.

[0064] S203, connecting the ice melting device in series between the bus and the ice melting line, wherein the input end of the rectifier module is connected to the bus, and the output end of the DC-DC module and the output end of the inverter module are connected to the ice melting line.

[0065] The ice melting device 303 is connected in series between the bus 301 and the ice melting line through the first switch S1 and the second switch S2. After taking power from the bus 301, the AC power is converted into DC power through the rectifier module to power the ice melting device 303. The output end of the DC-DC module and the output end of the inverter module are connected to the ice melting line, which is convenient for selecting the ice melting mode, that is, DC ice melting is performed through the DC-DC module, and AC ice melting is performed through the inverter module.

[0066] S204: Select a corresponding ice-melting mode according to the ice-melting line conditions.

[0067] Among them, the de-icing line conditions include the specific parameters of the line, grid conditions, availability of de-icing equipment, and economy. DC de-icing is to de-icing the entire line, which consumes a lot of energy, and the critical short-circuit current of DC de-icing is larger than that of AC de-icing. DC de-icing can be selected when the de-icing line is long. Since the reactance of the high-voltage AC line is much greater than the resistance, the power capacity required for AC de-icing is much greater than the capacity of DC de-icing. However, AC de-icing can be selected when there are many branches on the main de-icing line. Figure 3 As shown, the ice-melting line has many branches 304, and AC ice-melting can be used to melt the ice on the line.

[0068] S205: Start the ice melting device to melt ice.

[0069] After the ice melting method is determined, the ice melting device 303 is started to melt the ice. The ice melting voltage can be adjusted to melt the ice on the line. By changing the voltage applied to the ice melting line, the current flowing through the ice melting line is controlled, and the thermal effect of the current is used to melt the ice on the line.

[0070] Continue to refer Figure 3 In some optional embodiments of the embodiments of the present invention, after the ice melting device is started to melt ice, the method further includes:

[0071] Adjust the ice-melting voltage to melt the ice on the line;

[0072] After the ice is melted, the connection between the ice-melting device 303 and the busbar 301 and the ice-melting line is disconnected, and the power supply of the ice-melting line is restored.

[0073] Among them, when performing the ice melting operation, the current flowing through the ice melting line is controlled by changing the magnitude of the voltage applied to the ice melting line, and the ice on the line is melted by the thermal effect of the current. The setting of the ice melting voltage needs to take into account the actual parameters of the line, such as the length of the line, the resistance of the conductor, and the impedance of the line. For example, for longer lines, a higher voltage may be required to ensure that sufficient current passes to achieve ice melting. First, it is necessary to determine the required ice melting current based on the line type, temperature and other parameters of the ice melting line, and then estimate the required ice melting voltage based on the line length, impedance and other parameters. After the ice melting operation is completed, the ice layer on the ice-covered line has been melted. After the ice melting device 303 is disconnected from the bus 301 and the ice melting line, the power supply to the ice melting line can be restored by closing the third switch S3, and the power system will return to normal operation.

[0074] Continue to refer Figure 3 Specifically, the de-icing process of the de-icing line includes: firstly, the de-icing line is segmented by using the isolating switch 302 of the distribution network, the third switch S3 is disconnected, the power supply of the de-icing line is disconnected, and the de-icing short-circuit device 305 at the end of the de-icing line is opened; the de-icing short-circuit device 305 is operated to short-circuit the de-icing line; the first switch S1 is closed on the bus 301, and the bus 301 is connected to the de-icing device 303 at this time; the de-icing device 303 selects a corresponding de-icing mode according to the situation of the de-icing line, such as Figure 3 The ice-melting line shown has a large number of branches 304, and AC ice-melting can be used to melt the ice on the line; the second switch S2 is closed, and the ice-melting device 303 and the ice-melting line form an ice-melting loop; the ice-melting device 303 is started to melt the ice, and the ice-melting voltage is adjusted to melt the ice on the line; after the ice-melting is completed, the first switch S1 and the second switch S2 of the ice-melting device 303 are disconnected, and the third switch S3 is closed to restore power supply to the ice-melting line.

[0075] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0076] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An ice melting device, characterized in that: include: Rectification module, ice melting mode selection module, DC-DC module and inverter module; The input end of the rectifier module is connected to the bus, the output end of the rectifier module is connected to the ice melting mode selection module, and the rectifier module is used to take power from the bus and convert AC power into DC power; The ice-melting mode selection module is connected to the input end of the DC-DC module and the input end of the inverter module, and the ice-melting mode selection module is used to select the DC-DC module to melt ice or select the inverter module to melt ice according to the ice-melting line; The DC-DC module is connected in parallel with the inverter module, and the DC-DC module is used to output ice melting according to the direct current output by the rectifier module; the inverter module is used to convert the direct current output by the rectifier module into alternating current and then output ice melting.

2. The ice melting device according to claim 1, characterized in that: The DC-DC module is used to convert the direct current output by the rectifier module into a voltage value required for melting ice in the ice-melting circuit.

3. The ice melting device according to claim 1, characterized in that: The inverter module adopts a full-bridge inverter, and the full-bridge inverter is used for converting direct current into alternating current and then outputting it for ice melting.

4. The ice melting device according to claim 3, characterized in that: The full-bridge inverter includes an inverter circuit, a logic circuit, and a filter circuit; The inverter circuit is used to convert direct current into alternating current; the logic circuit is used to generate a control signal to control the inverter circuit; and the filter circuit is used to filter out unnecessary signals.

5. The ice melting device according to claim 1, characterized in that: The ice melting mode selection module includes a control module and two-way switches; The control module is used to control the switching of two-way switches; The two-way knife switches are connected to the output end of the rectifier module, the input end of the DC-DC module, and the input end of the inverter module. The control module is used to control one of the two-way knife switches to connect the output end of the rectifier module with the input end of the DC-DC module to switch the ice melting mode to DC ice melting, or control the other of the two-way knife switches to connect the output end of the rectifier module with the input end of the inverter module to switch the ice melting mode to AC ice melting.

6. The ice melting device according to claim 5, characterized in that: The two-way knife switches are remotely controlled switches, and one of the two-way knife switches is interlocked with the other.

7. The ice melting device according to claim 1, characterized in that: The rectifier module includes a power quality management unit, which is used to isolate the harmonic pollution caused by the DC-DC module and the inverter module to the power grid.

8. The ice melting device according to claim 1, characterized in that: In the power distribution line, the first section of the ice-melting line is connected to the output end of the ice-melting device, and the end of the ice-melting line is connected to the ice-melting short-circuit device.

9. An ice melting method, characterized in that: The ice melting device according to any one of claims 1 to 8 is used, and the ice melting method comprises: Controlling the isolation switch to segment the ice-melting line and disconnect the power supply of the ice-melting line; Opening the ice-melting short-circuiting device at the end of the ice-melting line to short-circuit the ice-melting line; The ice melting device is connected in series between the bus and the ice melting line, wherein the input end of the rectifier module is connected to the bus, and the output end of the DC-DC module and the output end of the inverter module are connected to the ice melting line; Selecting a corresponding ice melting mode according to the ice melting line conditions; The ice melting device is started to melt ice.

10. The ice melting method according to claim 9, characterized in that: After the ice melting device is started to melt ice, the method further comprises: Adjust the ice-melting voltage to melt the ice on the line; After the ice is melted, the connection between the ice-melting device and the busbar and the ice-melting line is disconnected, and the power supply of the ice-melting line is restored.

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