CN106207925B - A kind of distribution network line ice melting system and its de-icing method - Google Patents

Abstract

The invention discloses an ice-melting system and an ice-melting method for lines of a distribution network. The AC ice-melting unit includes an ice-melting switch, an ice-melting protection device, and a fixed ice-melting voltage output device. The long branch line mobile DC ice-melting unit includes a mobile ice-melting power generation device and a first ice-melting rectifier connected to each other. The short branch line is portable. The DC ice-melting unit includes a portable ice-melting power generation device and a second ice-melting rectification device connected to each other; the method includes selecting different ice-melting units to perform AC or DC ice melting according to the icing situation and line type. The invention is designed for the main line, long branch line and short branch line, covering all lines of the distribution network to melt ice, can improve the efficiency of line thawing in the distribution network and expand the scope of ice melting, and strengthen the lines of the distribution network to resist large-scale rain and snow freezing disasters ability.

Description

A system and method for melting ice of distribution network lines

technical field

The invention belongs to the technical field of electrical engineering, and in particular relates to an ice-melting system and an ice-melting method for distribution network lines.

Background technique

Since 2008, the large-scale rain, snow and freezing disasters in the south have caused heavy damage to the power systems of Hunan, Guizhou, Jiangxi, Zhejiang and other provinces. The distribution network lines are the most terminal of electricity sales, and they are widely distributed, mostly in micro-topographic and micro-meteorological areas. The frequent accidents of tower collapse and disconnection have directly affected the reliable power supply of users. The research and design of the distribution network line ice melting system is the key to ensure the reliability of power supply for users during ice disasters.

At present, there are not many studies on the distribution network ice melting system. The distribution network ice melting devices developed by some scientific research institutes are mainly aimed at melting short lines and ultra-short lines. Partial ice melting is carried out, and an ice melting system for a certain area has not yet been formed. Moreover, there are many mixed lines in the distribution network, and generally only small cross-section conductors can be deiced, which is difficult. When a large-scale ice disaster occurs, the current ice-melting device configuration is not enough to support all the lines of the distribution network system in this area to melt ice. Therefore, a set of ice melting system for distribution network lines is established, covering all main lines, long branch lines, and short branch lines of the distribution network. It is an urgent problem to be solved in improving the line's ability to resist large-scale rain, snow and freezing disasters.

Contents of the invention

The technical problem to be solved by the present invention: Aiming at the above-mentioned problems of the prior art, a system is designed for the main line, long branch line and short branch line of the distribution network, which covers the ice melting of all lines of the distribution network, and can effectively improve the power distribution system. The efficiency of ice melting of network lines and the expansion of ice melting range, and the distribution network line ice melting system and its ice melting method that enhance the ability of distribution network lines to resist large-scale rain and snow freezing disasters.

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is:

A method for melting ice of a distribution network line ice melting system, the distribution network line ice melting system includes a main line fixed AC ice melting unit, a long branch line mobile DC ice melting unit and a short branch line portable DC ice melting unit, the The main line fixed AC deicing unit is installed in the substation. The main line fixed AC deicing unit includes an deicing switch, an deicing protection device, and a fixed deicing voltage output device. The input end of the fixed deicing voltage output device The deicing protection device, the deicing switch and the 10kV bus of the substation are connected in turn, the control terminal of the deicing switch is connected with the deicing protection device, and the long branch line mobile DC deicing unit includes mobile deicing power generation units connected to each other. device and a first ice-melting rectification device, the short branch portable DC ice-melting unit includes a portable ice-melting power generation device and a second ice-melting rectification device connected to each other, and the steps include:

1) Detect the icing situation of the distribution network main line of the distribution network line. If the distribution network main line reaches the first specified proportion and the icing occurs, then jump to step 2); otherwise, when the distribution network main line is partially icing Jump to step 3);

2) If the icing on the main line of the distribution network reaches the preset ice-covering warning value, the small-section wire in the main line of the icing distribution network is used as the target line, and the output terminal of the fixed ice-melting voltage output device is connected to the target line Short the end of the target line to ground, turn on the ice melting switch to melt ice on the target line; skip to step 4);

3) If the partial icing of the main line of the distribution network reaches the preset icing warning value, the large-section conductor section in the partially icing main line of the distribution network is used as the target line, and the output end of the first ice-melting rectification device Connect to one end of the target line, and short-circuit the end of the target line to ground, and turn on the mobile ice-melting power generation device to perform DC melting on the target line; skip to step 4);

4) Detect the icing situation of the distribution network long branch line of the distribution network line. If the distribution network long branch line reaches the second specified proportion and the icing occurs, then jump to step 5); otherwise, when the distribution network long branch line is partially Skip to step 6 when covered with ice);

5) If the icing of the long branch line of the distribution network reaches the preset icing warning value, the small cross-section conductor in the main line of the distribution network and the long branch line of the distribution network covered with ice are connected in series as the target line, and the fixed ice melting The output terminal of the voltage output device is connected to the target line and the end of the target line is short-circuited to ground, and the ice melting switch is turned on to perform AC melting on the target line; skip to step 7);

6) If the local icing of the long branch line of the distribution network reaches the preset ice-covering warning value, the long branch line of the distribution network with partial icing is taken as the target line, and the output terminal of the first melting and rectifying device and the target line One end is connected, and the end of the target line is short-circuited to ground, and the mobile ice-melting power generation device is turned on to perform DC melting on the target line; skip to step 7);

7) For the target lines that are ice-covered between the partial distances of the distribution network lines or the fixed AC ice-melting unit of the main line and the mobile DC ice-melting unit of the long branch line cannot carry out ice-melting target lines, if the target line is ice-covered to the expected If the ice-covering warning value is set, the output end of the second ice-melting rectification device is connected to one end of the target line and the end of the target line is short-circuited to ground, and the portable ice-melting power generation device is turned on to perform DC melting on the target line.

Preferably, the connection to one end of the target line specifically refers to connecting to one end of each phase conductor of the target line through a connection clamp.

Preferably, the short-circuiting and grounding of the end of the target line refers to common connection of each phase wire at the end of the target line through a short-circuit wire and then grounding through a ground nail.

The distribution network circuit ice melting system of the present invention has the following advantages:

1. The distribution network line ice melting system of the present invention includes a main line fixed AC ice melting unit, a long branch line mobile DC ice melting unit and a short branch line portable DC ice melting unit, through the main line fixed AC ice melting unit, long branch line mobile type The DC ice-melting unit and the short branch line portable DC ice-melting unit can cover different distribution network line lengths at the same time, and can realize the ice melting of all distribution networks in a certain area, which greatly improves the resistance of distribution network lines to large-scale rain, snow and freezing disasters Ability.

2. The distribution network line ice melting system of the present invention includes a main line fixed AC ice melting unit, a long branch line mobile DC ice melting unit and a short branch line portable DC ice melting unit. This method takes into account the ice-melting capacity and the convenience of ice-melting when the distribution network line is ice-melted, and has strong implementability.

3. The distribution network line ice melting system of the present invention includes a main line fixed AC ice melting unit, a long branch line mobile DC ice melting unit and a short branch line portable DC ice melting unit, and AC and DC ice melting units can be flexibly selected for different line lengths The method reduces the workload of system operation and maintenance, and has strong ice-melting mobility and high ice-melting efficiency.

4. The distribution network line ice melting system of the present invention includes a main line fixed AC ice melting unit, a long branch line mobile DC ice melting unit and a short branch line portable DC ice melting unit, and different ice melting units can be selected for different line types and lengths The method solves the problem that there are many mixed line types in the distribution network and it is difficult to melt ice.

5. When the present invention melts ice for some lines, it can realize non-stop power supply of the main line and improve the reliability of power supply when the lines of the distribution network are melted.

Description of drawings

Fig. 1 is a schematic structural diagram of a distribution network line ice melting system in this embodiment.

Legend: 1. Fixed main line AC ice melting unit; 11. Ice melting switch; 12. Ice melting protection device; 13. Fixed ice melting voltage output device; 14. Ice melting knife gate; 2. Long branch line mobile DC ice melting Unit; 21. Mobile ice-melting power generation device; 22. First ice-melting rectification device; 23. Vehicle chassis; 24. First wiring device; 3. Short branch line portable DC ice-melting unit; . The second ice-melting rectification device; 33. The second wiring device.

Detailed ways

As shown in Figure 1, the distribution network line deicing system in this embodiment includes a main line fixed AC deicing unit 1, a long branch line mobile DC deicing unit 2 and a short branch portable DC deicing unit 3, and a main line fixed AC deicing unit The ice melting unit 1 is installed in the substation. The main line fixed AC ice melting unit 1 includes an ice melting switch 11, an ice melting protection device 12, and a fixed ice melting voltage output device 13. The input end of the fixed ice melting voltage output device 13 passes through the ice melting The protection device 12 and the ice-melting switch 11 are connected to the 10kV busbar of the substation, the control end of the ice-melting switch 11 is connected to the ice-melting protection device 12, and the long branch line mobile DC ice-melting unit 2 includes a mobile ice-melting power generation device 21 and The first ice-melting and rectifying device 22 and the short-branch portable DC ice-melting unit 3 include a portable ice-melting power generation device 31 and a second ice-melting and rectifying device 32 connected to each other.

In this embodiment, the 10kV busbar of the substation can be taken from the 35kV or 110kV substation of the corresponding regional distribution network according to the needs, and the ice melting switch 11 adopts the commercially available KYN28 type 10kV switchgear; the ice melting protection device 12 adopts the commercially available XDBH-10 type protection device , with the functions of overspeed break protection, current protection, and differential protection, and at the same time has the function of identifying and braking the inrush current, and jumps off the ice melting switch 11 to cut off the power supply when the ice melting fails; in this embodiment, the fixed ice melting voltage output device 13 is Multi-level voltage output device, specifically XDRB-7000 ice-melting device, with a capacity of 7000kVA and an input voltage of 10kV, can choose different gears for ice-melting voltage according to the line impedance to meet the ice-melting needs of different line types and lengths. In this embodiment, the output end of the fixed ice-melting voltage output device 13 is provided with an ice-melting knife switch 14, and the voltage output of the fixed ice-melting voltage output device 13 can be conveniently controlled through the ice-melting knife switch 14, which is safe and reliable. The ice-melting knife switch 14 specifically adopts the XDDZ-10.5 type knife switch with a rated voltage of 10.5kV and three-phase linkage to improve the reliability of operation.

The main line fixed AC ice melting unit 1 is mainly designed for the main line ice melting of the distribution network. The components are built inside the distribution network substation. The switch 11 is connected to the ice-melting protection device 12, the ice-melting protection device 12 is connected to the fixed ice-melting voltage output device 13, the fixed ice-melting voltage output device 13 is connected to the ice-melting knife gate 14, and the ice-melting knife gate 14 is connected to the waiting For the ice-melting wire, the three-phase short-circuit grounding is carried out at the end of the wire through a short-circuit wire to realize AC ice-melting. The main line of the distribution network is long and the ice melting power is large. The ice melting device with its own power generation system cannot meet its ice melting capacity, and the wire diameter of the distribution network is small, and the reactance component is equivalent to the resistance component. The advantage of AC ice melting is not obvious, so the main line fixed AC ice melting unit 1 of this embodiment adopts the method of taking power locally from the 10kV busbar of the substation, inputting it to the fixed ice melting voltage output device 13, and the fixed ice melting voltage output device 13 The low-voltage voltage is adjustable, and the appropriate gear can be selected according to different outlets to output three-phase AC voltage. The fixed ice-melting voltage output device 13 is connected to the main line to be ice-melted through the wiring clip, and the three-phase short-circuit is performed at the end of the main line through a short wire Grounding and turning on the ice-melting switch 11 can realize AC ice-melting. During ice-melting, the ice-melting protection device 12 is used to protect all equipment, and when a fault occurs, the ice-melting switch 11 is tripped. The mainline fixed AC deicing unit 1 can melt ice for 5km-30km mainline conductors.

In this embodiment, the mobile ice-melting power generation device 21 is a diesel generator, and the first ice-melting rectifying device 22 is a six-pulse rectifying device. The mobile ice-melting power generation device 21 specifically adopts a commercially available Cummins diesel generator, with a generating power of 320kW, a maximum output voltage of 400V, and continuous power generation for 15 hours each time; the first ice-melting rectifier 22 uses XDZL-600 six-pulse rectifier device, the rectification power is 600kW. In this embodiment, the long-branch mobile DC ice-melting unit 2 also includes a vehicle-mounted chassis 23, the vehicle-mounted chassis 23 adopts a commercially available Isuzu box truck, and the mobile ice-melting power generation device 21 and the first ice-melting rectification device 22 are respectively installed on the On the vehicle chassis 23. In this embodiment, the vehicle-mounted chassis 23 is provided with a first wiring device 24, and the first wiring device 24 is connected to the output end of the first melting and rectifying device 22. The first wiring device 24 specifically adopts a YDJX-500 type wiring device. The positive and negative poles of the DC output of the first ice melting and rectifying device 22 are connected to the three-phase line, and the rated current is 500A.

The long branch line mobile DC ice-melting unit 2 is mainly designed for partial ice-melting of the long branch line or main line of the distribution network. Ice rectifying device 22, the first melting and rectifying device 22 is connected to the first wiring device 24, the first wiring device 24 realizes the connection between the positive and negative poles of DC and the three phases of AC, and the first wiring device 24 passes through the wiring The clip is connected to the head end of the wire section to be melted, and the three-phase short-circuit grounding is performed at the end of the wire segment to be melted through the short wire, so as to realize local DC ice melting of long branch lines or main lines. The line type of the distribution network is complex, and there are often mixed erections of multiple line types on the branch line and some main lines. The fixed AC ice-melting unit 1 can only melt ice for small-diameter wires and large-diameter wires. There is a risk of burning small-diameter wires when the wires are thawed. The long-branch mobile DC ice-melting unit 2 uses a mobile ice-melting power generation device 21 as a power source, and after being rectified by the first ice-melting rectifier 22, it is connected to the wire section to be ice-melted through the wiring clip, and the wire section to be ice-melted Three-phase short-circuit grounding is carried out at the end through a short-circuit wire, and the mobile ice-melting power generation device 21 is started to realize DC ice-melting of a long branch line or a part of a main line. The long-branch mobile DC deicing unit 2 is integrally integrated on the vehicle chassis 23, which can be moved flexibly. Using DC deicing can reduce the capacity of the mobile deicing power generation device 21, reduce the volume of the vehicle chassis 23, and selectively Different ice-covered sections perform direct current melting. The long branch line mobile DC ice melting unit 2 can melt ice for 0-5km branch lines and local main lines.

In this embodiment, the portable ice-melting power generation device 31 is an intermediate frequency generator, and the second ice-melting rectifying device 32 is a six-pulse rectifying device. The portable ice-melting power generation device 31 specifically adopts the commercially available TF-12 type intermediate frequency generator, the generating power is 12kW, the maximum output voltage is 24V, and the weight is 70kg; the second ice-melting rectifier 32 specifically adopts the XDZL-15 type six-pulse generator Rectification device, rectification power 15kW. In this embodiment, the short-branch portable DC ice-melting unit 3 further includes a second wiring device 33 , and the second wiring device 33 is connected to the output end of the second ice-melting and rectifying device 32 . The second connection device 33 specifically adopts a YDJX-400 type connection device to connect the positive and negative poles of the DC output of the second ice-melting rectification device 32 with the three-phase line, and the rated current is 400A. The short-branch portable DC ice-melting unit 3 is mainly designed for melting ice on short-branch lines of distribution networks or lines that cannot be reached by vehicles. The short-branch portable DC ice-melting unit 3 can realize mobile ice melting based on the portable ice-melting power generation device 31 The portable ice-melting power generation device 31 is used as a power source, connected to the second ice-melting and rectifying device 32, and the second ice-melting and rectifying device 32 is connected to the second wiring device 33, and the second wiring device 33 is connected to the To the head end of the wire section to be thawed, three-phase short-circuit grounding is performed at the end of the wire segment to be thawed through the short wire, so as to realize DC thawing of short branch lines or lines that cannot be reached by vehicles. Many distribution networks are located in remote mountainous areas with obvious micro-topography and micro-climate. The situation of icing is serious, but the traffic is extremely inconvenient, and it is difficult for vehicles to enter. The short-line portable DC ice-melting unit 3 adopts the mode of a small power generation platform. The portable ice-melting power generation device 31 that can be carried by 4 people is used as the ice-melting power supply. Go to the wire section to be melted, perform three-phase short-circuit grounding through a short wire at the end of the wire to be melted, and start the portable ice-melting power generation device 31 to realize DC ice-melting for short branch lines or lines that cannot be reached by vehicles. The short-branch portable DC ice-melting unit 3 can melt ice for wires of 0-400m.

In summary, the distribution network line ice melting system in this embodiment includes a fixed AC ice melting unit 1 for the main line, a mobile DC ice melting unit 2 for long branch lines and a portable DC ice melting unit 3 for short branch lines, and has multiple power-taking methods , can flexibly choose the AC/DC ice melting method, the ice melting mobility is strong, and it can well solve the difficult problem of mixed line types in the distribution network and the ice melting difficulty, covering all the ice melting of the distribution network in a certain area, which greatly improves Improve the ability of distribution network lines to resist large-scale rain, snow and freezing disasters.

The steps of the ice melting method of the distribution network line ice melting system in this embodiment include:

1) Detect the icing situation of the distribution network main line of the distribution network line. If the distribution network main line reaches the first specified ratio (in this embodiment, the specific value is 30%, which can be adjusted according to the needs) and the icing occurs in the range above, Then skip to step 2); otherwise, when the main line of the distribution network is partially covered with ice, skip to step 3);

2) If the icing on the main line of the distribution network reaches the preset icing warning value, the small-section wire in the main line of the ice-covered distribution network is used as the target line, and the output terminal of the fixed ice-melting voltage output device 13 is connected to the target line Connect and short-circuit the end of the target line to ground, turn on the ice melting switch 11 to perform AC melting on the target line; skip to step 4);

3) If the partial icing of the main line of the distribution network reaches the preset icing warning value, the large-section conductor section in the partially icing main line of the distribution network is used as the target line, and the output of the first ice-melting and rectifying device 22 is used as the target line. end is connected to one end of the target line, and the end of the target line is short-circuited to ground, and the mobile ice-melting power generation device 21 is turned on to carry out DC melting of the target line; jump to step 4);

4) Detect the icing situation of the distribution network long branch line of the distribution network line. If the distribution network long branch line reaches the second specified proportion and the icing occurs, then jump to step 5); otherwise, when the distribution network long branch line is partially Skip to step 6 when covered with ice);

5) If the icing of the long branch line of the distribution network reaches the preset icing warning value, the small cross-section conductor in the main line of the distribution network and the long branch line of the distribution network covered with ice are connected in series as the target line, and the fixed ice melting The output end of the voltage output device 13 is connected to the target line and the end of the target line is short-circuited to ground, and the ice melting switch 11 is turned on to perform AC melting on the target line; skip to step 7);

6) If the partial icing of the long branch line of the distribution network reaches the preset icing warning value, then the long branch line of the distribution network with partial icing is taken as the target line, and the output end of the first melting and rectifying device 22 and the target line connected to one end of the target line, and the end of the target line is short-circuited to ground, and the mobile ice-melting power generation device 21 is turned on to perform DC melting of the target line; skip to step 7);

7) For the target line between the partial spans of the distribution network line that is ice-covered or the main line fixed AC ice-melting unit 1 and the long-branch mobile DC ice-melting unit 2 cannot carry out ice-melting target lines, if the target line is ice-covered When the preset ice-covering warning value is reached, connect the output end of the second ice-melting rectification device 32 to one end of the target line and short-circuit the end of the target line to ground, and turn on the portable ice-melting power generation device 31 to perform DC melting on the target line. ice.

In this embodiment, being connected to one end of the target line specifically refers to being connected to one end of each phase conductor of the target line through a connection clip. In this embodiment, the wiring clamp adopts the XDJJ-2 type fast wiring clamp, and the clamp can be directly connected to the head end of the line to be thawed. In this embodiment, short-circuiting and grounding the end of the target line refers to connecting the wires of each phase at the end of the target line to common connection through a short-circuit wire, and then grounding through a ground nail. In this embodiment, the shorting wire adopts the XDDJ-3 type shorting device, and the device is equipped with a grounding nail.

For example, in the distribution network line, the main line of a distribution network is a mixed line type of LGJ-95 and LGJ-70, and the length is 15km. Among them, the length of the LGJ-95 conductor is 9km, the length of the LGJ-70 conductor is 6km, and the length of the LGJ-70 conductor is 5km. Severe icing occurs in the section, and the icing warning value is about to be reached. According to the ice melting method of the distribution network line ice melting system in this embodiment, the main line fixed AC ice melting unit 1 is used for AC melting for the main line of the substation, the main line impedance: 4.99+j6.00Ω, and the LGJ-70 wire melting current The range is 290A to 420A, and the ice melting voltage range can be calculated from 3918V to 5674V according to the AC ice melting calculation formulas shown in formulas (1) and (2).

In formulas (1) and (2), U _min is the minimum value of the ice-melting voltage range, U _max is the maximum value of the ice-melting voltage range, I _min is the minimum value of the wire melting current range, and I _max is the wire melting current The maximum value of the range, R is the line resistance value, X is the line inductance value. Select the ice-melting voltage of the fixed ice-melting voltage output device 13 within this range, set the protection value of the ice-melting protection device 12, close the ice-melting knife switch 14, connect the fixed ice-melting voltage output device 13 and the waiting The first end of the ice-melting wire is short-circuited in three phases at the end of the wire, and the ice-melting switch 11 (circuit breaker) is turned on to start melting the wire. After the ice melting is finished, turn off the ice melting switch 11 and remove the wiring.

For example, in a distribution network line, an LGJ-50 branch line in a certain area has 3 km of serious ice covering, which is about to reach the ice-covering warning value. The local traffic is suitable for the long branch line mobile DC deicing unit 2 to enter. The ice-melting method of the ice system can adopt the long-branch mobile DC ice-melting unit 2 to carry out long-branch mobile DC ice-melting. Conductor impedance of the ice-covered section: 1.68+j1.55Ω, the melting range of the LGJ-50 conductor is 230A～350A, according to the calculation formula of DC melting

U _min =1.5I _min R (3)

U _max = 2I _max R (4)

In formulas (3) and (4), U _min is the minimum value of the ice-melting voltage range, U _max is the maximum value of the ice-melting voltage range, I _min is the minimum value of the wire melting current range, and I _max is the wire melting current The maximum value of the range, R is the line resistance value, where the coefficient is 2 when the three-phase connection is two-phase series connection, and the coefficient is 1.5 when the three-phase connection is two-phase connection. Calculate the DC ice-melting voltage range from 580V to 1176V. Place the mobile ice-melting part of the long branch line in the middle of the ice-covered wire section, and short-circuit at one end first. The DC ice-melting voltage range is only 1/2 (U _min ~ U _max ), that is, 290V ~ 588V.

The rated output voltage U _dc =1.25U _ac =500V of the long-branch mobile DC ice-melting unit 2 . Connect the output voltage of the long branch line mobile DC ice-melting unit 2 to the middle of the wire to be melted (target line) with a wiring clamp, connect the short wire to the end of the wire to be melted, start the mobile ice-melting power generation device 21, and adjust the melting When the ice current reaches an appropriate level, the ice melting can start. After the three-phase ice melting is completed, the mobile ice melting power generation device 21 is turned off, one end of the short circuit is removed, and the other end is connected with a three-phase short circuit, and the other half of the line is subjected to DC ice melting. After all lines have been thawed, remove the wiring.

For example, in a distribution network line, an LGJ-70 branch line in a certain area has 0.5km of serious ice, and the ice-covered section is located in a remote mountainous area, vehicles cannot enter, and the main line where the branch line is located has a mixed line type of LGJ-70 and LGJ-50 , the ice thickness is about to reach the ice-covering warning value. According to the ice-melting method of the distribution network line ice-melting system in this embodiment, the short-branch portable DC ice-melting unit 3 is used for short-branch portable DC ice-melting. Conductor impedance of the ice-covered section: 0.20+j0.20Ω, the melting range of the LGJ-70 conductor is 290A~420A, and the DC melting voltage range is 87V~168V calculated according to formulas (3) and (4). The rated output voltage U _dc =1.25U _ac =30V of the portable DC ice-melting unit 3 with short branch lines. In view of the strong mobility of the short-branch portable DC ice-melting unit 3, the ice-covered section is divided into five parts, and the DC ice-melting voltage of each part ranges from 17.4V to 33.6V. Within the ice capacity, use wiring clips to connect the portable ice-melting parts of the short branch line to the ice-melting section, make a three-phase short connection at the end, start the portable ice-melting power generation device 31, adjust the ice-melting current to an appropriate size, and start For ice melting, after the end of the three-phase ice melting, the portable ice melting power generation device 31 is turned off, and the next stage of ice melting starts until all five sections of ice melting are completely finished.

To sum up, the ice-melting method of the distribution network line ice-melting system in this embodiment can flexibly select the ice-melting method according to the ice-covered section and ice-covering situation of the line, which reduces the workload of system operation and maintenance. The ice has strong mobility and high ice-melting efficiency. It can melt ice for all distribution network lines in a certain area. The ice-melting range includes all main lines and branch lines, and adopts power supplies from substations, vehicle power supplies and portable power supplies. Three power-taking methods, taking into account the ice-melting capacity and the convenience of ice-melting when the distribution network line is ice-melted, are highly implementable.

The above descriptions are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions under the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those skilled in the art, some improvements and modifications without departing from the principles of the present invention should also be regarded as the protection scope of the present invention.

Claims (3)

1. A method for melting ice of a distribution network line ice melting system. The distribution network line ice melting system includes a main line fixed AC ice melting unit (1), a long branch line mobile DC ice melting unit (2) and a short branch line portable DC deicing unit (3), the main line fixed AC deicing unit (1) is arranged in the substation, the main line fixed AC deicing unit (1) includes deicing switch (11), deicing protection device ( 12), a fixed ice-melting voltage output device (13), the input end of the fixed ice-melting voltage output device (13) is connected to the 10kV bus bar of the substation through the ice-melting protection device (12), the ice-melting switch (11) in sequence, The control end of the ice-melting switch (11) is connected to the ice-melting protection device (12), and the long-branch mobile DC ice-melting unit (2) includes a mobile ice-melting power generation device (21) and a first melting ice-melting unit connected to each other. The ice rectification device (22), the short-branch portable DC ice melting unit (3) includes a portable ice melting power generation device (31) and a second ice melting rectification device (32) connected to each other, characterized in that the steps include: 1) Detect the icing situation of the distribution network main line of the distribution network line. If the distribution network main line reaches the first specified proportion and the icing occurs, then jump to step 2); otherwise, when the distribution network main line is partially icing Jump to step 3); 2) If the icing on the main line of the distribution network reaches the preset icing warning value, the small-section wire in the main line of the ice-covered distribution network is used as the target line, and the output terminal of the fixed ice-melting voltage output device (13) and the The target line is connected and the end of the target line is short-circuited to ground, and the ice melting switch (11) is turned on to melt the ice of the target line; skip to step 4); 3) If the partial icing of the main line of the distribution network reaches the preset icing warning value, the large-section conductor section in the partially icing main line of the distribution network is used as the target line, and the first ice-melting rectification device (22) The output end of the target line is connected to one end of the target line, and the end of the target line is short-circuited to ground, and the mobile ice-melting power generation device (21) is turned on to carry out DC melting of the target line; jump to step 4); 4) Detect the icing situation of the distribution network long branch line of the distribution network line. If the distribution network long branch line reaches the second specified proportion and the icing occurs, then jump to step 5); otherwise, when the distribution network long branch line is partially Skip to step 6 when covered with ice); 5) If the icing of the long branch line of the distribution network reaches the preset icing warning value, the small cross-section conductor in the main line of the distribution network and the long branch line of the distribution network covered with ice are connected in series as the target line, and the fixed ice melting The output end of the voltage output device (13) is connected to the target line and the end of the target line is short-circuited to ground, and the ice-melting switch (11) is turned on to perform AC melting on the target line; skip to step 7); 6) If the partial icing of the long branch line of the distribution network reaches the preset icing warning value, then the long branch line of the distribution network with partial icing is taken as the target line, and the output terminal of the first melting and rectifying device (22) and the One end of the target line is connected, and the end of the target line is short-circuited to ground, and the mobile ice-melting power generation device (21) is turned on to perform DC melting of the target line; skip to step 7); 7) Target lines that are covered with ice between some spans of distribution network lines or where the fixed AC ice-melting unit (1) of the main line and the mobile DC ice-melting unit (2) of the long branch line cannot carry out ice-melting target lines, if When the icing of the target line reaches the preset icing warning value, the output terminal of the second ice-melting rectification device (32) is connected to one end of the target line and the end of the target line is short-circuited to ground, and the portable ice-melting power generation device ( 31) Perform DC deicing on the target line. 2. The ice-melting method of the distribution network line ice-melting system according to claim 1, characterized in that, the connection with one end of the target line specifically refers to one end of each phase conductor of the target line through the wiring clamp and the target line respectively connected. 3. The ice-melting method of the distribution network line ice-melting system according to claim 2, wherein said short-circuiting the end of the target line to ground refers to connecting each phase wire at the end of the target line to After the common connection, it is grounded through the ground nail.