WO2013026253A1

WO2013026253A1 - Power transmission line de-icing system and method thereof implemented using back braking operation during the whole process

Info

Publication number: WO2013026253A1
Application number: PCT/CN2012/000740
Authority: WO
Inventors: 傅闯; 吴怡敏; 饶宏; 许树楷; 黎小林
Original assignee: 南方电网科学研究院有限责任公司; 中国电力顾问工程集团西南电力设计院
Priority date: 2011-08-25
Filing date: 2012-05-28
Publication date: 2013-02-28
Also published as: CN102290773B; CN102290773A

Abstract

A power transmission line de-icing system and method thereof implemented using a back braking operation during the whole process. The de-icing system includes a DC de-icing device, a conversion knife-switch, a de-icing access knife-switch and a de-icing short-circuit knife-switch connected to a de-icing line, a connection wire and a fitting. When performing short-circuit de-icing on the power transmission line, the de-icing line is connected to the de-icing bus through the de-icing access knife-switch inside the transformer station where the DC de-icing device is located, and the loop line is three-phase short-circuited by the de-icing short-circuit knife-switch at the opposite side of the line, enabling the power transmission line to enter the de-icing state. The de-icing system and method need not convert the line to be in the detection state during de-icing but can accomplish operation processes such as connection, short-circuit and revocation by way of a back braking operation. The defects such as long line shut-down time, low reliability and danger to the wiring personnel caused by on-site manual operations are improved. The de-icing access knife-switch and de-icing short-circuit knife-switch in the de-icing system are small in volume and particularly applicable to the existing transformer stations and have good applicability.

Description

Transmission line ice melting system and method thereof using the switching operation in the whole process

The invention patent relates to a transmission line ice melting system and a method thereof implemented by using a switching operation in the whole process, and belongs to an innovative technology of DC melting application of a transmission line transmission line. Background technique

Transmission line ice icing caused by low temperature rain, snow and ice weather is one of the serious threats faced by many countries' power systems. Severe ice icing can cause grid disconnection and tower collapse, resulting in large-scale blackouts and rapid recovery of power transmission. It is very difficult. For a long time, the threat of ice disaster has been a major technical problem that the power system industry has tried to cope with.

The 1998 North American storm brought severe impacts on the US and Canada grids, resulting in a wide range of power outages. In 2005, the cold, snow, and snow weather caused serious disasters to China's Central China and North China power grids. From January to February 2008, the cold, snow, and snow weather hit southern China, Central China, and East China again, causing large-scale, long-term outages in Guizhou, Hunan, Guangdong, Yunnan, Guangxi, and Jiangxi provinces. And the people’s lives have caused huge losses.

After the 2008 ice disaster, Chinese power science and technology workers independently researched and developed DC ice melting technology and devices, and successfully developed a high-power DC ice melting device with completely independent intellectual property rights, mainly including dedicated rectifier transformers, without dedicated rectifiers. Transformers and vehicle-mounted mobile models have been promoted and applied throughout the country. During the ice period from 2009 to 2011, only 19 sets of DC ice-melting devices installed in the Southern Power Grid have played a major role. A total of 234 DC ice meltings were carried out on UOkV and above, of which more than 40 times were 500kV AC lines, giving full play to DC. The power of the ice melting device. From the application of the current DC ice-melting device in the power grid, the connection (or isolation) of the ice-melting busbar on the DC side of the DC ice-melting device to the ice-melting bus line and the short-circuit (or isolation) of the ice-melting line are generally achieved manually. During the melting of the ice, the operator connects the busbar busbar to the line using tools and temporary shorting wires in the substation where the ice melting device is located, and then uses the temporary three-phase line as required in the opposite substation of the ice-melting line. Wiring is short-circuited, and the line must be switched to the inspection state during the connection and removal process, because the line hanging point is often higher than the ground, especially for the 500kV line, the line hanging point height Generally, it is more than 20 meters. In manual operation, it is not only time-consuming, but also has great work intensity and difficulty. According to the actual application experience of the site in 2009-211, the manual wiring time is greater than the actual melting time of the line, causing the line outage time to exceed the line melting time by more than twice, and the time required to complete a 500kV line melting ice exceeds 10 hours. The efficiency of melting ice is seriously affected. The connection between the melting ice bus and the ice melting line on the DC side of the existing DC ice melting device and the manual temporary field connection of the opposite side of the ice melting line have the disadvantages of long line outage time, high risk and poor reliability. Therefore, it is necessary to better solve the problem of connecting and isolating the ice melting circuit and the DC ice melting device, and shorten the connection and isolation time. The transmission line ice melting system and the method implemented by the switching operation in the whole process of the invention can solve the problem better, and the total melting time of a 500 kV line can be controlled within 4 hours. Summary of the invention

The object of the present invention is to provide a transmission line ice melting system which is implemented by using a switching operation in the whole process of the existing DC ice melting system and method, and does not need to convert the transmission line and the DC ice melting device into maintenance during the ice melting process. State, the system does not require manual temporary wiring during the implementation of the melting line of the transmission line. The facilities and equipment required for the present invention mainly include a DC ice melting device, a conversion knife gate, a melting ice accessing knife gate connected to the ice melting circuit, a melting ice shorting knife gate, a connecting wire and a fitting. The invention has reasonable design, convenience and practicality.

Another object of the present invention is to provide a DC ice melting method for a transmission line that is simple in operation and convenient to use.

The technical solution of the present invention is: the transmission line melting ice system implemented by the switching operation in the whole process of the invention, including the DC ice melting device DI, the DC side switching knife gates S1, S2, S3 and S4, the melting ice bus DB, melting Ice access to the knife gate SA, the ice melting transmission line TL, the ice melting short circuit breaker SC, and the DC ice melting device DI and the circuit breaker QF connected to the busbar in the substation of the substation, the isolation knife gate K, the transmission line TL The circuit breaker QFA connected to the AC busbar of the station, the isolation knife gate KA, the circuit breaker QFB connected to the corresponding AC bus of the substation Q station, the isolation knife gate KB, the one end of the DC converter switch gates SI and S2 are short. After connecting, it is connected with the negative pole of the DC ice melting device DI, and the short-circuiting of the DC-side switching knife S3 and S4-end is connected with the positive pole of the DC ice-melting device DI; the other end of the DC-side switching knife gate S1 and the melting ice bus DB In the A phase connection, the other ends of the DC side switching knife gates S2 and S3 are shorted and connected to the B in the melting ice bus DB, and the other end of the DC side switching knife gate S4 is connected to the C in the melting ice bus DB; The low pressure side of the ice access knife gate SA is connected to the ice melting bus bar DB, and the high pressure side of the ice melting access knife gate SA is connected with the power transmission line TL; the low voltage side of the ice shorting knife gate SC is shorted, and the ice melting short circuit knife The high voltage side of the gate SC is connected to the power transmission line TL.

The connection and isolation of the above-mentioned transmission line TL and the DC ice melting device DI are realized by the ice-impregnating knife gate SA and the melting ice shorting knife gate SC.

When the above-mentioned DC ice-melting device DI adopts two six-pulse bridge series structure, the midpoint of the two bridges is the only grounding point of the DC ice-melting system. When a single six-pulse bridge is used or two six-pulse bridges are used in parallel structure, the DC ice-melting system is not connected. location.

The above-mentioned melting ice accessing knife gate SA and the melting ice shorting knife gate SC are composed of three single-column one-arm vertical telescopic isolation knife gates or single-column double-arm vertical telescopic isolation knife gates.

The low-pressure end of the three vertical telescopic knife gates in the above-mentioned ice-melting short-circuiting knife gate is short-circuited, and the low-pressure end of the three vertical telescopic knife gates in the ice-impregnated knife gate SA is not short-circuited.

The vertical telescopic knife gate used in the above-mentioned ice-impacting knife gate SA and the ice-melting short-circuit knife gate includes a high-voltage supporting insulating porcelain bottle, a low-voltage supporting insulating porcelain bottle, an operating insulating porcelain bottle, a vertically-opening main knife gate, a static contact, and a dynamic touch. a head, a pressure equalizing ring, a high voltage terminal block, a low voltage terminal block, a main knife electric operating mechanism; a top end of the high voltage supporting insulating porcelain bottle and a bottom surface of the equalizing ring are fixedly electrically connected; the top surface of the high voltage supporting insulating porcelain bottle is fixed The high-voltage terminal block is installed, the bottom surface of the equalizing ring is also fixedly mounted with a static contact, and the static contact, the high-voltage terminal block and the equalizing ring are electrically connected; the low-voltage supporting insulating porcelain bottle and the operating porcelain bottle are of the same height and mutual Parallel and connected to the upper end; the top end of the low-voltage support insulating porcelain bottle is fixedly connected with the low-voltage terminal block and the vertical open type main knife, and the low-voltage terminal board is electrically conductively fixedly connected with the lower end of the vertical open main-knife. The top of the vertical open main knife gate and the movable contact are electrically conductively fixedly connected; the main knife gate electric operating mechanism and the vertical opening The main knife gates are connected by operating the porcelain bottle drive; the length of the vertically open main knife gate is extended to make the movable contact contact with the static contact, and the vertical open main knife gate is not extended when the movable contact and the static contact The distance between them meets the moving contact The level of insulation between the static contact and the static contact is the same as the insulation level of the power switchgear required for the melting line voltage level.

The insulation level of the low-voltage support insulating porcelain bottle and the operating insulating porcelain bottle of the above-mentioned ice-melting inlet knife and the ice-shrinking knife are the same. The insulation level of the high-voltage supporting insulating porcelain bottle is much higher than that of the low-voltage supporting insulating porcelain bottle and the operating insulating porcelain bottle. Level.

The length of the high-voltage supporting insulating porcelain bottle satisfies the same level of insulation required for the high-voltage supporting insulating porcelain bottle and the grounding insulation TL voltage level; the length of the low-voltage supporting insulating porcelain bottle and the operating insulating porcelain bottle satisfy the insulation level and the direct current melting The level of insulation required for ground is the same as that required for the ice voltage of the ice device.

The low-voltage terminal block of the three vertical telescopic knife gates in the above-mentioned ice-melting short-circuiting knife gate SC is connected to the busbar and the connection.

The ice melting method of the transmission line ice melting system implemented by the switching operation in the whole process of the invention comprises the following steps:

1) Converting the transmission line TL that needs to be melted into a hot standby state, that is, the P station disconnects the circuit breaker QFA connected to the transmission line TL and the P station bus, and disconnects the circuit breaker QFB connected to the corresponding bus of the B station;

2) Converting the transmission line TL that needs to be melted into a cold standby state, that is, the P station disconnects the isolation knife gate KA connected to the transmission line TL and the P station bus, and disconnects the isolation knife gate connected with the corresponding bus of the B station;

3) P station closes the transmission line TL and the DC ice-melting device DI connected to the ice-melting access knife gate SA, Q station closes the ice-melting short-circuiting knife gate SC connected to the transmission line, that is, the transmission line TL exits the cold standby state , entering the state of melting ice;

4) Close the DC side switching knife switches S1 and S3 and confirm that S2 and S4 are disconnected;

5) Close the DC ice melting device DI AC side isolation knife gate K and circuit breaker QF;

6) Start the DC ice melting device DI, raise the DC current to the design melting current of the transmission line TL, wait for the A and B phase conductors to fall off the ice, that is, use the "one to one" DC melting mode to realize the A and B phases. The wire is melted in series, and the DC melting device DI is blocked after melting the A and B phase lines;

7) Start the ice-melting mode switching logic after the DC ice-melting device DI is locked, and disconnect the DC-side switching knife S3, close the DC side switching knife gates S2 and S4, that is, make Sl, S2 and S4 are closed, S3 is disconnected, enter the "two to one return" DC melting mode, that is, the A and B phase wires are connected in parallel and then the C phase conductor Tandem

8) Start the DC ice-melting device DI, raise the DC current to the design melting current of the transmission line TL, wait for the C-phase wire to fall off the ice, and complete the blocking of the DC ice-melting device DI after the C-phase wire is melted;

9) Disconnect DC ice melting device DI AC side circuit breaker QF and isolation knife K;

10) Disconnect the DC side transfer switches Sl, S2 and S4 and confirm that Sl, S2, S3 and S4 are disconnected;

11) The P station disconnects the transmission line TL and the ice melting device DI is connected to the ice-melting knife gate SA, and the Q station disconnects the melting ice shorting knife gate SC connected to the transmission line TL, that is, the transmission line TL exits the melting ice State, enter the cold standby state;

12) Convert the transmission line TL to the hot standby state, that is, the P station closes the isolation circuit gate connected to the transmission line TL and the P station bus, and the B station closes the isolation knife gate connected with the corresponding bus line;

13) Convert the transmission line TL to the running state, that is, after the A station closes the circuit breaker QFA connected to the transmission line TL and the P station bus, the Q station closes the circuit breaker QFB connected to the corresponding bus.

Compared with the prior art, the invention has the following characteristics:

1) The invention is convenient to operate, no manual field wiring is needed, no tools are needed, manpower and material resources are saved, and personal injury may be avoided at the time of manual wiring.

2) The invention greatly shortens the line outage time when melting ice, and the method in the present invention can

The total melting time of the 500kV line is controlled within 4 hours. Through the operation of the closing operation, the access and disconnection of the ice melting device is completed, and there is no transfer repair time on the line, which greatly improves the melting efficiency.

3) The invention has high reliability. Manual temporary wiring may result in unreliable access reliability due to unreasonable operation, which makes the melting of ice impossible. The automatic access is achieved by this scheme, and the reliability is greatly improved.

4) The main equipment used in the ice-melting method of the present invention is a set of ice-melting accessing knife gates and a set of ice-melting short-circuiting knife gates, and three single-column one-arm vertical telescopic isolating knife gates or The single-column double-arm vertical telescopic isolating knife gate is realized, and the land occupation is small. When the reconstructed project of the completed substation is implemented, it is generally unnecessary to carry out new land acquisition and has good implementation feasibility. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a transmission line ice melting system implemented by a switching operation in the whole process; FIG. 2 is a front view of a single column single arm vertical telescopic isolating knife; FIG. 3 is a single column single arm vertical telescopic FIG. 4 is a front view of a single-column double vertical telescopic isolating knife gate; FIG. 5 is a side view of a single-column double vertical telescopic isolating knife gate; The connecting gate adopts three single-column single-arm vertical telescopic isolation knife gates on the low-voltage side short-circuit diagram;

Figure 7 is a schematic diagram of the short-circuiting of the low-pressure side of the three-column vertical telescopic isolating knife gate for the ice-shrinking short-circuit knife gate;

Figure 8 is a schematic view showing the ice melting method of the transmission line ice melting system implemented by the switching operation in the whole process of the present invention.

detailed description

The whole process of the invention utilizes the transmission line melting system implemented by the switching operation, including the DC ice melting device DI, the DC side switching knife gates S1, S2, S3 and S4, the melting ice bus bar DB, and the melting ice accessing the knife gate SA. Need to melt the ice transmission line TL, melt the ice short circuit breaker SC, and the DC ice melting device DI and the circuit breaker QF connected to the busbar in the substation of the substation, the isolation knife gate K, the transmission line TL and the station AC bus connection Circuit breaker QFA, isolation knife gate KA, transmission line TL and another substation Q station corresponding AC bus connection circuit breaker QFB, isolation knife gate KB, DC side conversion knife gates SI and S2 one end shorted with DC ice melting device The DI negative pole is connected, the DC side switching knife gates S3 and S4 are short-circuited and connected to the DC ice-melting device DI positive pole; the other end of the DC-side switching knife gate S1 is connected with the A in the ice melting busbar DB, and the DC-side switching knife gate After the other ends of S2 and S3 are short-circuited, they are connected with B in the melting ice bus DB, and the other end of the DC-side switching knife gate S4 is connected with C in the melting ice bus DB. The low-pressure side of the melting ice is connected to the knife gate SA. Ice busbar DB connection, melting ice into the high pressure of the knife gate SA Connected to the transmission line TL; ice-melting low-side short knife shorting SC, SC melting ice short knife pressure side is connected to the transmission line TL. The connection and isolation of the above-mentioned transmission line TL and the DC ice-melting device DI are realized by the ice-melting access knife gate SA and the ice-melting short-circuiting knife gate SC.

The low-voltage end of the three vertical telescopic knife gates in the above-mentioned ice-melting short-circuit knife gate is short-circuited, and the low-voltage terminals of the three vertical telescopic knife gates in the ice-impregnated knife gate SA are not short-circuited.

The vertical telescopic knife switch used for the above-mentioned ice-melting access knife gate SA and the ice-melting short-circuit knife gate includes a high-voltage supporting insulating porcelain bottle 1, a low-voltage supporting insulating porcelain bottle 2, an operating insulating porcelain bottle 3, a vertically-opening main knife gate 4, and a static touch. The head 5, the moving contact 6, the equalizing ring 7, the high voltage terminal block 8, the low voltage terminal board 9, the main knife electric operating mechanism 10; the top end of the high voltage supporting insulating porcelain bottle 1 and the bottom surface of the equalizing ring 7 are fixedly conductive The top surface of the high-voltage supporting insulating porcelain bottle 1 is fixedly mounted with a high-voltage terminal block 8, the bottom surface of the equalizing ring 7 is also fixedly mounted with a static contact 5, and the static contact 5, the high-voltage terminal block 8 and the pressure equalization The ring 7 is electrically connected; the low-voltage supporting insulating porcelain bottle 2 is equal to the operating porcelain bottle 3, parallel to each other and connected to the upper end; the low-voltage supporting insulating porcelain bottle 2 is fixedly connected with the low-voltage terminal block 9 and the vertical open main switch 4. The low-voltage terminal block 9 and the lower end of the vertical open main switch 4 are electrically conductively fixedly connected, and the top end of the vertical open main switch 4 and the movable contact 6 are guided. The fixed connection; the main knife electric operation mechanism 10 and the vertical opening main switch 4 are connected by the operation of the porcelain bottle 3; the length of the vertical open main switch 4 after extension can make the movable contact 6 and the static contact 5 contact, When the vertical open main switch 4 is not extended, the distance between the movable contact 6 and the static contact 5 satisfies the insulation level between the movable contact 6 and the static contact 5 and the power switch required by the voltage level of the ice melting line The insulation level of the equipment break is the same.

The low-voltage supporting insulating porcelain bottle 2 and the operating insulating porcelain bottle 3 of the above-mentioned ice-melting access knife gate SA and the ice-melting short-circuiting knife gate SC have the same insulation level, and the insulation level of the high-voltage supporting insulating porcelain bottle 1 is much higher than that of the low-voltage support. The insulation level of the edge porcelain bottle 2 and the operation of the insulating porcelain bottle 3.

The length of the high-voltage supporting insulating porcelain bottle 1 satisfies the insulation level of the high-voltage supporting insulating porcelain bottle 1 and the grounding insulation level required for the melting line TL voltage level; the length of the low-voltage supporting insulating porcelain bottle 2 and the operating insulating porcelain bottle 3 satisfy the insulation thereof The level of insulation required for the horizontal and the DC ice melting device melting ice bus DB voltage level is the same.

The low-voltage terminal block 9 of the three vertical telescopic knife gates in the above-mentioned ice-melting short-circuiting knife gate SC is connected by connecting the bus bars 11 and 12.

2) Converting the transmission line TL that needs to be melted into a cold standby state, that is, the P station disconnects the isolation knife gate KA connected to the transmission line TL and the P station bus, and disconnects the isolation knife gate connected with the corresponding bus line of the B station;

7) DC ice-melting device starts the ice-melting mode switching logic after DI lock, disconnects the DC-side switching knife switch S3, closes the DC-side switching knife gates S2 and S4, so that Sl, S2 and S4 are closed, S3 is disconnected, enter

"Two to one" DC melting mode, that is, the A and B phase conductors are connected in parallel and then connected in series with the C phase conductor;

8) Start the DC ice-melting device DI, raise the DC current to the design melting ice current of the transmission line TL, wait for the C-phase wire to fall off the ice, and complete the DC-melting device DI after the C-phase wire is melted; 9) Disconnect the DC AC side circuit breaker QF and the isolating knife K from the DC ice melting device;

Claims

1. The transmission line melting system implemented by the switching operation in the whole process is characterized by including DC ice melting device DI, DC side switching knife gates S1, S2, S3 and S4, melting ice bus bar DB, melting ice accessing the knife gate SA, need to melt ice transmission line TL, melt ice short circuit breaker SC, and DC ice melting device DI and the circuit breaker QF connected to the bus station in the substation P station, isolation knife gate K, transmission line TL and station AC bus Connected circuit breaker QFA, isolation knife gate KA, transmission line TL and another substation Q station corresponding AC bus connection circuit breaker QFB, isolation knife gate KB, DC side conversion knife gates SI and S2 one end shorted with DC The ice device DI is connected to the negative pole, and the DC side switching knife gates S3 and S4 are short-circuited and connected to the DC ice-melting device DI positive electrode; the other end of the DC-side switching knife gate S1 is connected with the A in the melting ice bus DB, DC side conversion The other ends of the knife gates S2 and S3 are short-circuited and connected to the B in the ice-melting bus bar DB, and the other end of the DC-side switching knife gate S4 is connected to the C in the ice-melting bus bar DB; the ice-melting is connected to the low-pressure side of the knife gate SA And melting Bus DB is connected, the access melting ice knife SA pressure side is connected with the transmission line TL; melting ice short knife shorting the low pressure side SC, SC melting ice short knife pressure side is connected to the transmission line TL.

2. The power transmission line ice melting system implemented by the switching operation according to claim 1, wherein the connection and isolation of the power transmission line TL and the DC ice melting device DI are integrated into the blade and the melt through the ice melting. Ice shorting knife gate SC is realized.

3. The power transmission line ice melting system implemented by the switching operation according to claim 1, wherein the DC ice melting device DI adopts two six-pulse bridge series structures, and the midpoint of the two bridges is a DC ice melting system. The only grounding point is that there is no grounding point for the DC ice-melting system when using a single six-pulse bridge or two six-pulse bridges in parallel.

4. The transmission line ice melting system implemented by the entire operation process according to claim 1, wherein the melting ice accessing knife gate SA and the melting ice shorting knife gate SC adopt three single column single arm vertical Telescopic isolation knife gate or single-column double vertical telescopic isolation knife gate.

5. The transmission line ice melting system implemented by the switching operation according to claim 1, wherein the low-voltage end of the three vertical telescopic knife gates in the ice-shrinking knife gate SC is short-circuited, melting ice The low-voltage ends of the three vertical telescopic knife gates in the access knife gate SA are not short-circuited.

6. The ice melting circuit of the transmission line implemented by the switching operation according to claims 1 to 5 The system is characterized in that the vertical telescopic knife gate adopted by the above-mentioned ice-impacting knife gate SA and the ice-melting short-circuit knife gate comprises a high-voltage supporting insulating porcelain bottle (1), a low-voltage supporting insulating porcelain bottle (2), and an operating insulating porcelain bottle (3) ), vertical open main knife gate (4), static contact (5), moving contact (6), pressure equalizing ring (7), high voltage terminal block (8), low voltage terminal block (9), main knife gate The electric operating mechanism (10); the top end of the high-voltage supporting insulating porcelain bottle (1) is fixedly electrically connected with the bottom surface of the equalizing ring (7); the top surface of the high-voltage supporting insulating porcelain bottle (1) is fixedly mounted with a high-voltage terminal board (8), the bottom surface of the pressure equalizing ring (7) is also fixedly mounted with a static contact (5), and the static contact (5), the high voltage terminal block (8) and the equalizing ring (7) are electrically connected The low-voltage support insulating porcelain bottle (2) is parallel to the operating porcelain bottle (3), parallel to each other and connected to the upper end; the low-voltage supporting insulating porcelain bottle (2) is fixedly connected with the low-voltage terminal block (9) and the vertical opening main knife Brake (4), low voltage terminal block (9) and vertical open main switch (4) The lower end is electrically conductively fixedly connected, and the top of the vertical open main knife (4) and the movable contact (6) are electrically conductively fixedly connected; the main knife electric operating mechanism (10) and the vertical open type main knife ( 4) by operating the porcelain bottle (3) transmission connection; the length of the vertically open main knife gate (4) after extension can make the moving contact (6) and the static contact (5) contact, the vertical opening main knife The distance between the moving contact (6) and the static contact (5) when the brake (4) is not extended satisfies the insulation level between the moving contact (6) and the static contact (5) and the voltage level of the ice melting line. The required insulation level of the power switchgear is the same.

7. The transmission line ice melting system implemented by the switching operation according to any one of claims 1 to 5, characterized in that the above-mentioned ice-impregnated knife gate SA and the ice-shrinking short-circuit knife SC low-voltage support insulating porcelain bottle ( 2) The insulation level of the insulated porcelain bottle (3) is the same as that of the high-voltage supporting insulating porcelain bottle (1), which is much higher than that of the low-voltage supporting insulating porcelain bottle (2) and the operating insulating porcelain bottle (3).

8. The transmission line ice melting system implemented by the switching operation according to any one of claims 1 to 5, characterized in that the length of the high-voltage supporting insulating porcelain bottle (1) satisfies the high-voltage supporting insulating porcelain bottle

The insulation level of (1) is the same as the insulation level required for the TL voltage level of the ice-melting line; the length of the low-voltage support insulating porcelain bottle (2) and the operating insulating porcelain bottle (3) satisfy the insulation level and the DC ice melting device The insulation level required for the ice busbar DB voltage level is the same.

9. The ice melting circuit of the transmission line implemented by the switching operation according to any of claims 1 to 5 The system is characterized in that the low-voltage terminal strips (9) of the three vertical telescopic cutters in the ice-shrinking knife gate SC are connected by connecting the busbars (11) and (12).

10. The ice melting method of the transmission line ice melting system implemented by the switching operation in the whole process includes the following steps:

11) The P station disconnects the transmission line TL and the ice melting device DI is connected to the ice-melting knife gate SA, and the Q station disconnects the melting ice shorting knife gate SC connected to the transmission line TL, that is, the transmission line TL exits the melting ice State, enter the cold standby state; 12) Converting the transmission line TL into a hot standby state, that is, the P station closes the isolation knife gate KA connected to the transmission line TL and the P station bus, and the B station closes the isolation knife gate KB connected with the corresponding bus line;