Medium-voltage expansion ice melting device and ice melting expansion system

Abstract

The invention relates to a medium-voltage expansion ice melting device and an ice melting expansion system. The medium-voltage expansion ice melting device comprises an ice melting transformer and a reactive compensation unit, the primary side of the ice-melting transformer is electrically connected with the power supply end of the medium-voltage power supply, and the secondary side of the ice-melting transformer and the input end of the reactive compensation unit are electrically connected with the ice-melting output end; wherein the ice melting transformer is a double-winding ice melting transformer of which the primary side is subjected to on-load voltage regulation and the secondary side is subjected to no-load gear regulation, and the medium-voltage power supply comprises a medium-voltage emergency power supply vehicle or a power grid; the deicing transformer is used for adjusting the alternating current of the medium-voltage power supply into the adjustable alternating current of the line section to be deiced, and the reactive compensation unit is used for regulating and controlling the reactive compensation current and the reactive compensation power. According to the technical scheme of the invention, the medium-voltage emergency generator car can be fully utilized to quickly expand the ice melting function of the medium-voltage emergency generator car, and meanwhile, the ice melting technical equipment of power grid power supply can be considered, and the economy of distribution network ice melting is improved.

Description

Technical Field

[0001] The present disclosure relates to the field of electrical engineering technology, and in particular to a medium-voltage extended ice-melting device and an extended ice-melting system. Background Art

[0002] Agricultural distribution lines are usually located in rural areas with diverse natural environments, such as high-altitude mountainous areas. Due to the vast rural areas, compared with urban distribution networks, agricultural distribution lines are located in harsh environments, with longer lines, more lines, and wider distribution, making them more susceptible to micro-topography and micro-meteorological freezing disasters.

[0003] In the related technologies, in order to reduce the impact of ice disasters on power lines, various de-icing and ice-melting technologies have been studied at home and abroad. Dozens of de-icing methods have been proposed, which are generally divided into thermal de-icing, artificial de-icing, natural passive de-icing, etc. according to their working principles. Electric current de-icing is an efficient means for power grids to improve their ability to prevent and control ice disasters on lines. It is widely used in main power transmission lines and has achieved good results. Electric current de-icing is an efficient means for power grids to improve their ability to prevent and control ice disasters on lines. It is widely used in main power transmission lines and has achieved good results. However, existing DC de-icing devices cannot achieve de-icing under medium voltage power supply scenarios, which severely limits the de-icing efficiency. Summary of the invention

[0004] In order to solve the above technical problems or at least partially solve the above technical problems, the present disclosure provides a medium-pressure extended ice melting device and system, which improves the ice melting efficiency.

[0005] In a first aspect, the present disclosure provides a medium-pressure extended ice melting device, comprising:

[0006] Ice melting transformer and reactive power compensation unit;

[0007] The primary side of the ice-melting transformer is electrically connected to the power supply end of the medium voltage power supply, and the secondary side of the ice-melting transformer and the input end of the reactive power compensation unit are both electrically connected to the ice-melting output end;

[0008] Wherein, the ice-melting transformer is a double-winding ice-melting transformer with on-load voltage regulation on the primary side and off-load voltage regulation on the secondary side, and the medium-voltage power supply includes a medium-voltage emergency power supply vehicle or a power grid;

[0009] The ice-melting transformer is used to adjust the alternating current of the medium-voltage power supply to an adjustable alternating current in the line section to be ice-melted, and the reactive compensation unit is used to regulate reactive compensation current and reactive compensation power.

[0010] Optionally, the reactive power compensation unit includes a capacitor group; the capacitor group includes a plurality of capacitor units connected in parallel, and the input ends of the plurality of capacitor units are electrically connected in parallel and electrically connected to the secondary side of the ice-melting transformer;

[0011] Each group of capacitor units includes a capacitor and a switch connected in series. The capacitor to be switched into operation can be determined by controlling the on and off of the switch to adjust the reactive compensation current and reactive compensation power.

[0012] Optionally, the medium voltage extended ice melting device further comprises: a measurement and control protection unit and a circuit breaker, wherein the circuit breaker is connected in series between the primary side of the ice melting transformer and the power supply end of the medium voltage power supply, the measurement and control protection unit is electrically connected to the secondary side of the ice melting transformer, the ice melting output end and the input end of the reactive power compensation unit respectively, and the measurement and control protection unit is also electrically connected to the circuit breaker;

[0013] The measurement, control and protection unit is used to control the on and off of the circuit breaker according to the internal state and output state quantity of the medium-voltage extended ice-melting device.

[0014] Optionally, the measurement, control and protection unit includes:

[0015] A first current transformer, arranged at the secondary output end of the ice-melting transformer, for detecting the current at the secondary output end of the ice-melting transformer;

[0016] a second current transformer, arranged at the input end of the reactive power compensation unit, and used for detecting the current at the input end of the reactive power compensation unit;

[0017] A third current transformer, disposed at the ice-melting output end, for detecting the current at the ice-melting output end;

[0018] A voltage transformer is arranged at the ice-melting output end and is used for detecting the voltage at the ice-melting output end.

[0019] In a second aspect, the present disclosure further provides an ice melting extension system applicable to a medium voltage emergency power supply vehicle, comprising the medium voltage extended ice melting device as described in the first aspect; the system further comprises:

[0020] Ice-melting connecting cables and ice-melting short-circuit switches;

[0021] The input end of the medium voltage extended ice melting device is electrically connected to the medium voltage emergency power supply vehicle, the output end of the medium voltage extended ice melting device is connected to the ice-melting line through the ice-melting connection cable, and the end of the ice-covered section of the ice-melting line is short-circuited with the three-phase of the ice-melting short-circuit knife switch;

[0022] The medium-voltage extended ice-melting device is used to adjust the AC power supply of the medium-voltage emergency power supply vehicle to adjustable AC power in the line section to be ice-melted.

[0023] Optionally, the medium voltage emergency power supply vehicle is a 10kV emergency power generation vehicle.

[0024] Optionally, the medium voltage emergency power supply vehicle is deployed separately from the medium voltage extended ice melting device.

[0025] In a third aspect, the present disclosure further provides an ice melting extension system suitable for power grid power supply, comprising the medium voltage extended ice melting device described in the first aspect; the system further comprises:

[0026] Ice-melting connection cables, ice-melting short-circuit switches, ice-melting bypass switches, ice-melting input switches and ice-melting output switches;

[0027] The input end of the medium-voltage extended ice-melting device is electrically connected to the output end of the ice-melting input switch via the ice-melting connection cable, the input end of the ice-melting input switch and the input end of the ice-melting bypass switch are both connected to the power grid, the output end of the medium-voltage extended ice-melting device is electrically connected to the input end of the ice-melting output switch via the ice-melting connection cable, the output end of the ice-melting output switch and the output end of the ice-melting bypass switch are both connected to the line to be ice-melted, and the end of the ice-covered section of the line to be ice-melted is short-circuited in three phases by the ice-melting short-circuit switch;

[0028] The medium voltage extended ice-melting device is used to adjust the alternating current of the power grid into adjustable alternating current in the line section to be ice-melted.

[0029] Optionally, the power grid is a 10kV distribution network.

[0030] Optionally, the power grid and the medium voltage extended ice melting device are deployed integrally.

[0031] Compared with the prior art, the technical solution provided by the embodiments of the present disclosure has the following advantages:

[0032] The disclosed embodiment provides a medium voltage extended ice-melting device and system, the medium voltage extended ice-melting device includes: an ice-melting transformer and a reactive power compensation unit; the primary side of the ice-melting transformer is electrically connected to the power supply end of the medium voltage power supply, and the secondary side of the ice-melting transformer and the input end of the capacitor bank are both electrically connected to the ice-melting output end; wherein the ice-melting transformer is a double-winding ice-melting transformer with on-load voltage regulation on the primary side and off-load gear adjustment on the secondary side; the ice-melting transformer is used to adjust the alternating current at the power supply end to an adjustable alternating current in the line section to be de-iced, the reactive power compensation unit is used to regulate the reactive power compensation current and reactive power, and the medium voltage power supply includes a medium voltage emergency power supply vehicle or a power grid. Thus, by using a double-winding ice-melting transformer with on-load voltage regulation on the primary side and off-load gear adjustment on the secondary side, power can be taken from the power supply end of the medium voltage power supply, which can fully utilize the medium voltage emergency power generation vehicle to quickly expand its de-icing function, while taking into account the de-icing technical equipment powered by the power grid, thereby improving the economy of de-icing in the distribution network. In addition, in the ice-melting transformer used, the primary side on-load voltage regulation does not need to cut off the load current, so no arc will be generated during the voltage regulation process, avoiding damage to the tap changer in the ice-melting transformer. The secondary side no-load shifting is to improve the stability of the voltage and reduce the impact of load changes on the voltage in the power system by adjusting the magnetic flux of the voltage regulating winding when there is no load or light load. The reactive compensation unit is used to regulate the size of the reactive compensation current, and then regulate the current of the primary and secondary sides of the ice-melting transformer to avoid the actual output current of the ice-melting transformer and the generator set exceeding the limit. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0035] Figure 1 A schematic structural diagram of a medium-pressure extended ice melting device provided in an embodiment of the present disclosure;

[0036] Figure 2 An ice melting expansion system suitable for a medium voltage emergency power supply vehicle is provided in an embodiment of the present disclosure;

[0037] Figure 3 An ice melting expansion system suitable for power grid power supply is provided in an embodiment of the present disclosure.

[0038] Among them, the correspondence between the figure numbers and the structures is: 1. ice-melting transformer; 2. reactive power compensation unit; 3. measurement, control and protection unit; 4. circuit breaker; 20. capacitor unit; 21. capacitor; 22. switch; 31. first current transformer; 32. second current transformer; 33. third current transformer; 34. voltage transformer; 10. medium-voltage extended ice-melting device; 101. ice-melting connection cable; 102. ice-melting short-circuit switch; 103. medium-voltage emergency power supply vehicle; 104. ice-melting bypass switch; 105. ice-melting input switch; 106. ice-melting output switch; 107. distribution transformer; U1. power supply end of medium-voltage power supply; U2. ice-melting output end. DETAILED DESCRIPTION

[0039] In order to more clearly understand the above-mentioned objectives, features and advantages of the present disclosure, the scheme of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0040] In the following description, many specific details are set forth to facilitate a full understanding of the present disclosure, but the present disclosure may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present disclosure, rather than all of the embodiments.

[0041] In the related technologies, in terms of current ice melting in distribution lines, various ice melting systems and corresponding equipment have been developed at home and abroad in just a few years, mainly including: fixed ice melting devices installed in substations, mobile ice melting devices on large power supply vehicles that can be deployed movably, segmented ice melting devices that can melt ice at the rear section of the line by drawing power from the line, and low-voltage extended ice melting devices that can be adapted to conventional emergency power supply vehicles.

[0042] The de-icing device includes: a fixed de-icing system, which is fixedly installed in the substation and draws power from the busbar in the station to de-ice the substation outgoing lines. During de-icing, the three-phase short circuit is required at the end of the ice-covered section and the power is cut off on the entire line. In theory, all ice-covered outgoing lines in the station can be de-iced.

[0043] The mobile ice-melting system of the power supply vehicle does not need to rely on the power supply of the substation. It can be deployed at the front end of the ice-covered section at will. The three phases at the end of the ice-covered section are short-circuited. The ice-covered lines are melted by the power supply of the power supply vehicle itself. In theory, the ice-covered lines in an area can be melted.

[0044] The segmented ice-melting system is installed at a fixed point in the middle and rear end of the line, draws power from the front end of the line, and short-circuits the three phases at the end of the ice-covered section, which can melt the ice at the end of the main line and the ice-covered section of the branch line, with a small power outage range and strong targeting.

[0045] The extended ice-melting system is used with a conventional power supply vehicle. It can be deployed movably and powered by the power supply vehicle. The ice-covered lines are melted after the current is converted by the device. The device is small and has strong emergency response, and can meet the ice-melting needs of the lines in an area.

[0046] A mobile DC ice-melting device for a power supply vehicle in the prior art is composed of a low-voltage generator set, a current-boosting transformer, and a six-pulse rectifier. The complete structure includes a transformer and a rectifier component to achieve voltage and current matching for ice melting. The device has many components, a large complete set volume, and is difficult to transport. The prior art also provides a portable generator set type DC ice-melting device, which is composed of a gasoline generator set and a rectifier module. After the medium-frequency generator generates electricity, it is converted into DC power for DC ice melting. However, the device has low power and a short ice melting distance. The prior art provides an ice-melting function expansion system based on a conventional power supply vehicle, which expands a conventional 400V low-voltage power supply vehicle to have an ice-melting function similar to that of a special ice-melting device. Existing mobile distribution network ice-melting equipment usually needs to be equipped with a dedicated generator set to form a complete set of dedicated ice-melting devices, or an extended ice-melting system used with a low-voltage 400V power supply vehicle. There is currently no extended ice-melting system that can be used for both line power supply and medium-voltage emergency power supply vehicles. To address this problem, there is an urgent need for an ice-melting technology equipment that can fully utilize the medium-voltage emergency generator vehicle to quickly expand its ice-melting function while taking into account the power supply of the power grid, so as to improve the economy of distribution network ice-melting.

[0047] Figure 1 A medium-pressure extended ice melting device is provided in an embodiment of the present disclosure, such as Figure 1 As shown, the medium voltage extended ice-melting device 10 includes: an ice-melting transformer 1 and a reactive compensation unit 2; the primary side of the ice-melting transformer 1 is electrically connected to the power supply terminal U1 of the medium voltage power supply, and the secondary side of the ice-melting transformer 1 and the input end of the reactive compensation unit 2 are both electrically connected to the ice-melting output terminal U2; wherein, the ice-melting transformer 1 is a double-winding ice-melting transformer 1 with on-load voltage regulation on the primary side and off-load gear regulation on the secondary side, and the medium voltage power supply is a medium voltage emergency power supply vehicle or a power grid; the ice-melting transformer 1 is used to adjust the alternating current of the power supply terminal U1 of the medium voltage power supply to an adjustable alternating current in the line section to be melted, and the reactive compensation unit 2 is used to regulate the reactive compensation current and the reactive compensation power.

[0048] Specifically, Figure 1 As shown, the medium voltage extended ice melting device 10 takes power from the power supply terminal U1 of the medium voltage power supply, and is converted into an adjustable voltage source through the ice melting transformer 1 and the reactive power compensation unit 2. The output voltage of the ice melting device 10 acts on the ice melting line to be melted through the ice melting output terminal U2 ( Figure 1 (not shown in the figure), after the three phases are short-circuited by the de-icing short-circuiting knife switch at the end of the line to be de-iced, the line is equivalent to a resistive and inductive impedance related to the wire model and length.

[0049] The ice-melting transformer 1 used in the embodiment of the present disclosure is a double-winding ice-melting transformer 1 with on-load voltage regulation on the primary side and off-load gear shifting on the secondary side. It can control the ice-melting voltage applied to the ice-melting line, and then adjust the current of the ice-melting line to achieve the predetermined line ice melting. The on-load voltage regulation on the primary side does not need to cut off the load current, so no arc will be generated during the voltage regulation process, avoiding damage to the tap switch in the ice-melting transformer 1. Off-load gear shifting is to improve the stability of the voltage and reduce the impact of load changes on the voltage in the power system by adjusting the magnetic flux of the voltage regulating winding when there is no load or light load.

[0050] Exemplarily, before the medium-voltage extended ice-melting device 10 is used, the gear of the secondary side of the ice-melting transformer 1 can be pre-set according to the relevant parameters of the line to be melted, and the gear of the primary side of the ice-melting transformer 1 can be set to the lowest. After the power supply terminal U1 of the medium-voltage power supply is powered, the gear of the primary side of the ice-melting transformer 1 is gradually increased. Thus, the double-winding ice-melting transformer 1 with on-load voltage regulation on the primary side and off-load gear regulation on the secondary side can avoid the shutdown of the power supply terminal U1 of the medium-voltage power supply. For example, when a conventional medium-voltage emergency power supply vehicle is used as a power supply, according to the sudden load capacity of the conventional medium-voltage emergency power supply vehicle, an on-load voltage regulating switch is added to the primary side of the ice-melting transformer 1 and the voltage regulating gear is designed, so that when the conventional medium-voltage emergency power supply vehicle 103 passes through the line to be melted by the device, it will not exceed its sudden load limit and cause protection action or even shutdown.

[0051] It should be noted that the specific structure of the double-winding ice-melting transformer 1 with on-load voltage regulation on the primary side and off-load gear regulation on the secondary side can be set according to actual use requirements, and the embodiments of the present disclosure are not limited to this.

[0052] For example, the parameters of the ice melting transformer 1 used in the embodiment of the present disclosure are, for example, a rated capacity of 1250 kVA, a rated input voltage of 10 kV, a rated output voltage of 2.5 kV, and a rated output current of 300 A. The primary side has 5 gears configured for on-load voltage regulation: 12-11-10-9-8 kV; the secondary side has 5 gears configured for off-load voltage regulation: 2.5-2.0-1.5-1.0-0.5 kV. In other embodiments, other parameters may also be selected, and the embodiment of the present disclosure is not limited to this.

[0053] The ice-melting transformer 1 and the reactive power compensation unit 2 jointly provide the current and power required for line ice-melting, wherein the ice-melting transformer 1 supports the required line ice-melting voltage and provides all the required active power and part of the reactive power. The reactive power compensation unit 2 provides most of the reactive power required for line ice-melting, and the remaining part is provided by the ice-melting transformer 1, which can reduce the output current and output power of the ice-melting transformer 1. The secondary current of the ice-melting transformer 1 is equal to the vector difference between the current of the line to be ice-melted and the reactive power compensation current. The reactive power compensation unit 2 is used to adjust the size of the reactive power compensation current, and then adjust the current of the primary and secondary sides of the ice-melting transformer 1 to avoid the current of the actual output of the ice-melting transformer 1 and the generator set from exceeding the limit.

[0054] The disclosed embodiment of the present invention realizes power drawing from the power supply terminal U1 of the medium-voltage power supply by utilizing a double-winding ice-melting transformer 1 with on-load voltage regulation on the primary side and off-load gear adjustment on the secondary side. It can fully utilize the medium-voltage emergency power generation vehicle to quickly expand its ice-melting function, while taking into account the ice-melting technical equipment of the power grid, thereby improving the economy of ice-melting in the distribution network. In addition, in the ice-melting transformer 1 used, the on-load voltage regulation on the primary side does not need to cut off the load current, so no arc will be generated during the voltage regulation process, thereby avoiding damage to the tap switch in the ice-melting transformer. The off-load gear adjustment on the secondary side is to improve the stability of the voltage and reduce the impact of load changes on the voltage in the power system when there is no load or light load by adjusting the magnetic flux of the voltage regulating winding. The reactive compensation unit 2 is used to regulate the size of the reactive compensation current, and then regulate the current of the primary and secondary sides of the ice-melting transformer 1 to avoid the current actually output by the ice-melting transformer 1 and the generator set from exceeding the limit.

[0055] Optionally, the reactive compensation unit 2 includes a capacitor group; the capacitor group includes a plurality of capacitor units 20 connected in parallel, the input ends of the plurality of capacitor units 20 are electrically connected in parallel to each other, and are electrically connected to the secondary side of the ice-melting transformer 1; each capacitor unit 20 includes a capacitor 21 and a switch 22 connected in series, and the capacitor 21 that is put into operation can be determined by controlling the on and off of the switch 22 to regulate the reactive compensation current and the reactive compensation power.

[0056] Specifically, the capacitor group serves as the reactive power compensation unit 2, and the capacitor group includes a plurality of groups of three-phase capacitor units 20 connected in parallel. Each group of capacitor units 20 can be three-phase star-connected or cross-connected. The input ends of the plurality of groups of capacitor units 20 are electrically connected in parallel to each other and are electrically connected to the secondary side of the ice-melting transformer 1. Each group of capacitor units 20 can include one or more switches 22 and one or more capacitors 21 connected in series. For each group of capacitor units 20, the on and off of the switch 22 can determine whether the capacitor 21 of the group of capacitor units 20 is switched on or off.

[0057] In addition to the capacitor 21 and the switch 22, the capacitor unit 20 may also include other components. For example, each group of capacitor units 20 may include an isolating switch, a capacitor, a fuse, a discharge resistor, etc. The number of capacitor units 20 can be set to multiple groups, which can be grouped and switched according to the reactive power demand of the ice-melting line. For a longer ice-melting line, even in the initial power-on stage, the power supply end U1 of the medium-voltage power supply, such as a medium-voltage power supply vehicle, can drive the ice-melting line, but because its operating power factor continues to decrease during the pressurization process, it will cause shutdown. Therefore, in the embodiment of the present disclosure, the capacitor group number set single group capacitor unit 20 is designed and put into use according to the reactive power demand of the ice-melting line parameters, ensuring that the power supply end U1 of the medium-voltage power supply, such as a conventional medium-voltage power supply vehicle, reaches 0.8 or above, thereby improving the reliability of use. In addition, the rated voltage of the capacitor group is designed according to the maximum rated voltage of the secondary side of the on-load tap-changing ice-melting transformer 1.

[0058] Illustratively, the capacitor bank provided in the embodiment of the present disclosure has a rated capacity of 3000 kvar and is designed as three groups of capacitor units 20, each with a rated capacity of 1000 kvar and a rated voltage of 2.5 kV.

[0059] Alternatively, if Figure 1 As shown, the medium-voltage extended ice-melting device 10 also includes: a measurement and control protection unit 3 and a circuit breaker 4. The circuit breaker 4 is connected in series between the primary side of the ice-melting transformer 1 and the power supply terminal U1 of the medium-voltage power supply. The measurement and control protection unit 3 is electrically connected to the secondary side of the ice-melting transformer 1, the ice-melting output terminal U2 and the input terminal of the reactive power compensation unit 2, respectively. The measurement and control protection unit 3 is also electrically connected to the circuit breaker 4. The measurement and control protection unit 3 is used to control the on and off of the circuit breaker 4 according to the internal state and output state quantity of the medium-voltage extended ice-melting device 10.

[0060] Specifically, Figure 1 As shown, the circuit breaker 4 can be, for example, a circuit breaker. The monitoring and control protection unit 3 is used to output a trip signal to the circuit breaker 4 according to at least one of the secondary current of the ice-melting transformer 1, the voltage of the ice-melting output terminal U2, the current of the ice-melting output terminal U2, and the current of the input terminal of the reactive compensation unit 2 exceeding a preset overvoltage and overcurrent protection value, so as to cut off the electrical connection between the medium-voltage power supply and the medium-voltage extended ice-melting device 10, so as to improve the use safety of the medium-voltage extended ice-melting device 10.

[0061] Exemplarily, the circuit breaker 4 may adopt a conventional 10 kV circuit breaker structure, with a specific model of ZW32C-12GP / 630-20, a rated voltage of 10 kV, a rated current of 630 A, and a rated short-circuit breaking current of 20 kA.

[0062] Alternatively, if Figure 1As shown, the measurement, control and protection unit 3 includes: a first current transformer 31, which is arranged at the secondary output end of the ice-melting transformer 1, and is used to detect the current at the secondary output end of the ice-melting transformer 1; a second current transformer 32, which is arranged at the input end of the reactive power compensation unit 2, and is used to detect the current at the input end of the reactive power compensation unit 2; a third current transformer 33, which is arranged at the ice-melting output end U2, and is used to detect the current of the ice-melting output end U2; a voltage transformer 34, which is arranged at the ice-melting output end U2, and is used to detect the voltage of the ice-melting output end U2.

[0063] Specifically, the first current transformer 31, the second current transformer 32, the third current transformer 33 and the voltage transformer 34 are respectively configured with a voltmeter and an ammeter, which are used to display the values ​​of the current and voltage detected by these transformers. For example, the measurement and control protection unit 3 may also include a first ammeter corresponding to the first current transformer 31, a second ammeter corresponding to the second current transformer 32, a third ammeter corresponding to the third current transformer 33 and a voltmeter corresponding to the voltage transformer 34.

[0064] In some embodiments, a threshold value can be set for each ammeter and voltmeter. In addition to displaying the value detected by the corresponding circuit transformer and voltage transformer 34, each ammeter and voltmeter can output an overcurrent or overvoltage protection signal when the detected value exceeds the respective threshold value. The protection signals of each signal are connected in parallel to output a total protection signal. In some embodiments, the total protection signal can be sent to the processor, which can output a trip signal to the circuit breaker 4 after receiving the total protection signal. In other embodiments, the total protection signal can be directly sent to the circuit breaker 4 to disconnect the circuit breaker 4.

[0065] Exemplarily, the measurement and control protection unit 3 includes a first ammeter, which is configured to receive and display the current at the secondary output terminal detected by the first current transformer 31, and to send a first overcurrent protection signal when the current at the secondary output terminal exceeds a first current threshold; a second ammeter, which is configured to receive and display the current at the input terminal of the reactive compensation unit 2 detected by the second current transformer 32, and to send a second overcurrent protection signal when the current at the input terminal of the reactive compensation unit 2 exceeds a second current threshold; a third ammeter, which is configured to receive and display the current at the ice-melting output terminal U2 detected by the third current transformer 33, and to send a third overcurrent protection signal when the current at the ice-melting output terminal U2 exceeds a third current threshold; a voltmeter, which is configured to receive and display the voltage at the ice-melting output port detected by the voltage transformer 34, and to send an overvoltage protection signal when the voltage at the ice-melting output terminal U2 exceeds a voltage threshold. The first overcurrent protection signal, the second overcurrent protection signal, the third overcurrent protection signal, and the overvoltage protection signal are connected in parallel to output a total protection signal as a trip signal.

[0066] The disclosed embodiment also provides an ice melting expansion system suitable for a medium voltage emergency power supply vehicle. Figure 2 An ice melting expansion system for a medium voltage emergency power supply vehicle is provided in an embodiment of the present disclosure, such as Figure 2 As shown, the ice-melting extension system suitable for the medium-voltage emergency power supply vehicle 103 includes the medium-voltage extended ice-melting device 10 provided in the above-mentioned embodiment; the ice-melting extension system of the medium-voltage emergency power supply vehicle 103 also includes: an ice-melting connection cable 101 and an ice-melting short-circuit switch 102; the input end of the medium-voltage extended ice-melting device 10 is electrically connected to the medium-voltage emergency power supply vehicle 103, and the output end of the medium-voltage extended ice-melting device 10 is connected to the ice-melting line to be melted through the ice-melting connection cable 101, and the end of the ice-covered section of the ice-melting line to be melted is short-circuited in three phases with the ice-melting short-circuit switch 102; the medium-voltage extended ice-melting device 10 is used to adjust the AC power supply of the medium-voltage emergency power supply vehicle 103 to an adjustable AC power in the ice-melting line section. Figure 2 The shaded area in the figure represents the ice-covered section of the line to be de-iced, and the de-icing short-circuit switch 102 is in a state of not short-circuiting the three phases.

[0067] Specifically, Figure 2 As shown, the embodiment of the present disclosure utilizes the medium voltage extended ice melting device 10 to expand the conventional medium voltage power supply vehicle to have an ice melting function similar to that of the dedicated ice melting device, thereby making full use of the resources of the existing medium voltage emergency power supply vehicle 103 and quickly expanding its ice melting function.

[0068] For example, the ice melting connection cable 101 is of model ZC-YJV22-8.7 / 15kV-1×185mm 2 Cable, rated voltage 10kV, rated current 300A.

[0069] Optionally, the medium voltage emergency power supply vehicle 103 is a 10 kV emergency power generation vehicle.

[0070] Therefore, the medium voltage extended ice melting device 10 is used to realize the ice melting extension system of the medium voltage emergency power supply vehicle 103 using the 10 kV emergency power generation vehicle as the medium voltage power supply, thereby expanding the existing ice melting equipment.

[0071] Alternatively, if Figure 2 As shown, the medium voltage emergency power supply vehicle 103 is deployed separately from the medium voltage extended ice melting device 10.

[0072] Specifically, Figure 2 As shown, in order to avoid occupying too much space of the medium-voltage emergency power supply vehicle 103, the medium-voltage emergency power supply vehicle 103 and the medium-voltage extended ice-melting device 10 can be separately deployed.

[0073] For example, Figure 2The structure of the distribution transformer 107 is also shown in the figure. The specific usage is well known to those skilled in the art and will not be described in detail here.

[0074] The disclosed embodiment also provides an ice melting expansion system suitable for power grid power supply. Figure 3 An ice melting expansion system suitable for power grid power supply is provided in an embodiment of the present disclosure, such as Figure 3 As shown, the ice-melting extension system suitable for power supply of the grid includes the medium-voltage extended ice-melting device provided in the above embodiment, and the ice-melting extension system suitable for power supply of the grid also includes: an ice-melting connection cable 101, an ice-melting short-circuit switch 102, an ice-melting bypass switch 104, an ice-melting input switch 105 and an ice-melting output switch 106; the input end of the medium-voltage extended ice-melting device 10 is electrically connected to the output end of the ice-melting input switch 105 via the ice-melting connection cable 101, and the input end of the ice-melting input switch 105 is electrically connected to the output end of the ice-melting input switch 105. The input ends of the medium-voltage extended ice-melting device 10 and the ice-melting bypass switch 104 are both connected to the power grid, the output end of the medium-voltage extended ice-melting device 10 is electrically connected to the input end of the ice-melting output switch 106 via the ice-melting connecting cable 101, the output end of the ice-melting output switch 106 and the output end of the ice-melting bypass switch 104 are both connected to the line to be melted, and the end of the ice-covered section of the line to be melted is short-circuited in three phases with the ice-melting short-circuit switch 102; the medium-voltage extended ice-melting device 10 is used to adjust the alternating current of the power grid to adjustable alternating current in the section of the line to be melted. Figure 3 The shaded area in the figure represents the ice-covered section of the line to be de-iced, and the de-icing short-circuit switch 102 is in a state of not short-circuiting the three phases.

[0075] Specifically, Figure 3 As shown, when the power is supplied by the medium voltage power supply grid, the medium voltage extended ice melting device 10 is used to step down the AC power of the medium voltage power supply grid into an adjustable AC power for the line section to be ice-melted. Exemplarily, in the ice-melting stage, the ice-melting bypass switch 104 is in an open state, and the ice-melting input switch 105 and the ice-melting output switch 106 are in a closed state; when the power is supplied normally, the ice-melting bypass switch 104 is in a closed state, and the ice-melting input switch 105 and the ice-melting output switch 106 are in an open state.

[0076] Therefore, the disclosed embodiment can utilize the medium voltage extended ice-melting device 10 to enable mobile emergency deployment, transform the grid power supply into adjustable alternating current in the line section to be de-iced, and improve the economy of distribution network de-icing.

[0077] Optionally, the power grid is a 10kV distribution grid.

[0078] Therefore, mobile distribution network ice-melting equipment does not need to have its own dedicated generator set to form a complete set of dedicated ice-melting equipment to melt ice, thereby improving the economy of distribution network ice-melting.

[0079] Optionally, the power grid and the medium voltage extended ice melting device 10 are deployed integrally.

[0080] Specifically, the power grid and the medium voltage extended ice melting device 10 can be deployed as one, and on-site wiring is no longer required when ice melting is required, which improves the convenience of using the medium voltage extended ice melting device 10 and greatly reduces the workload of on-site wiring.

[0081] For example, Figure 3 The structure of the distribution transformer 107 is also shown in the figure. The specific usage is well known to those skilled in the art and will not be described in detail here.

[0082] Exemplarily, in the above-mentioned embodiment, the ice-melting short-circuit switch 102, the ice-melting bypass switch 104, the ice-melting input switch 105 and the ice-melting output switch 106 are three-phase linkage isolation switches with a rated voltage of 10 kV and a rated current of 630A.

[0083] The disclosed embodiment provides an ice-melting expansion system suitable for medium-voltage emergency power supply vehicles and power grid power supply, which can expand conventional medium-voltage power supply vehicles to have ice-melting functions similar to special ice-melting devices, and can also take power from the power grid and convert it into ice-melting current for the rear-end lines, with strong mobility and applicability. The disclosed embodiment can make full use of the existing medium-voltage emergency power generation vehicle resources and quickly expand its ice-melting function; it can also be deployed in a mobile emergency manner, converting the power grid power into ice-melting current for the rear-end lines, and improving the economic efficiency of ice-melting in the distribution network.

[0084] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0085] The above are only specific embodiments of the present disclosure, so that those skilled in the art can understand or implement the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to these embodiments herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A medium pressure extended ice melting device, characterized in that: include: Ice melting transformer and reactive power compensation unit; The primary side of the ice-melting transformer is electrically connected to the power supply end of the medium voltage power supply, and the secondary side of the ice-melting transformer and the input end of the reactive power compensation unit are both electrically connected to the ice-melting output end; Wherein, the ice-melting transformer is a double-winding ice-melting transformer with on-load voltage regulation on the primary side and off-load voltage regulation on the secondary side, and the medium-voltage power supply includes a medium-voltage emergency power supply vehicle or a power grid; The ice-melting transformer is used to adjust the alternating current of the medium-voltage power supply to an adjustable alternating current in the line section to be ice-melted, and the reactive compensation unit is used to regulate reactive compensation current and reactive compensation power.

2. The medium pressure extended ice melting device according to claim 1, characterized in that: The reactive power compensation unit includes a capacitor group; the capacitor group includes a plurality of capacitor units connected in parallel, the input ends of the plurality of capacitor units are electrically connected in parallel and are electrically connected to the secondary side of the ice-melting transformer; Each group of capacitor units includes a capacitor and a switch connected in series. The capacitor to be switched into operation can be determined by controlling the on and off of the switch to adjust the reactive compensation current and reactive compensation power.

3. The medium pressure extended ice melting device according to claim 1, characterized in that: Also includes: A measurement and control protection unit and a circuit breaker, wherein the circuit breaker is connected in series between the primary side of the ice-melting transformer and the power supply end of the medium-voltage power supply, the measurement and control protection unit is electrically connected to the secondary side of the ice-melting transformer, the ice-melting output end and the input end of the reactive power compensation unit respectively, and the measurement and control protection unit is also electrically connected to the circuit breaker; The measurement, control and protection unit is used to control the on and off of the circuit breaker according to the internal state and output state quantity of the medium-voltage extended ice-melting device.

4. The medium pressure extended ice melting device according to claim 3, characterized in that: The measurement, control and protection unit comprises: A first current transformer, arranged at the secondary output end of the ice-melting transformer, for detecting the current at the secondary output end of the ice-melting transformer; a second current transformer, arranged at the input end of the reactive power compensation unit, and used for detecting the current at the input end of the reactive power compensation unit; A third current transformer, disposed at the ice-melting output end, for detecting the current at the ice-melting output end; A voltage transformer is arranged at the ice-melting output end and is used for detecting the voltage at the ice-melting output end.

5. An ice melting expansion system suitable for a medium voltage emergency power supply vehicle, characterized in that: The system comprises the medium-pressure extended ice melting device according to any one of claims 1 to 4; the system further comprises: Ice-melting connecting cables and ice-melting short-circuit switches; The input end of the medium voltage extended ice melting device is electrically connected to the medium voltage emergency power supply vehicle, the output end of the medium voltage extended ice melting device is connected to the ice-melting line through the ice-melting connection cable, and the end of the ice-covered section of the ice-melting line is short-circuited with the three-phase of the ice-melting short-circuit knife switch; The medium-voltage extended ice-melting device is used to adjust the AC power supply of the medium-voltage emergency power supply vehicle to adjustable AC power in the line section to be ice-melted.

6. The ice melting expansion system for a medium voltage emergency power supply vehicle according to claim 5, characterized in that: The medium voltage emergency power supply vehicle is a 10kV emergency power generation vehicle.

7. The ice melting expansion system for a medium voltage emergency power supply vehicle according to claim 5, characterized in that: The medium voltage emergency power supply vehicle is deployed separately from the medium voltage extended ice melting device.

8. An ice melting expansion system suitable for grid-powered power supply, characterized in that: The system comprises the medium-pressure extended ice melting device according to any one of claims 1 to 4; the system further comprises: Ice-melting connection cables, ice-melting short-circuit switches, ice-melting bypass switches, ice-melting input switches and ice-melting output switches; The input end of the medium-voltage extended ice-melting device is electrically connected to the output end of the ice-melting input switch via the ice-melting connection cable, the input end of the ice-melting input switch and the input end of the ice-melting bypass switch are both connected to the power grid, the output end of the medium-voltage extended ice-melting device is electrically connected to the input end of the ice-melting output switch via the ice-melting connection cable, the output end of the ice-melting output switch and the output end of the ice-melting bypass switch are both connected to the line to be ice-melted, and the end of the ice-covered section of the line to be ice-melted is short-circuited in three phases by the ice-melting short-circuit switch; The medium voltage extended ice-melting device is used to adjust the alternating current of the power grid into adjustable alternating current in the line section to be ice-melted.

9. The ice melting expansion system suitable for grid-powered power supply according to claim 8, characterized in that: The power grid is a 10kV distribution network.

10. The ice melting expansion system suitable for grid power supply according to claim 8, characterized in that: The power grid and the medium voltage extended ice melting device are deployed integrally.

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