1.1.1 History of Live Working&Tools...
1.First Stage of Development of Tools and Instruments for Live Working
Live working technology in China started in the 1950s when Anshan Iron and steel factory,the largest iron and steel base in China at that time,had a very high dependence on power energy to the extent that even the power outage necessary for grid maintenance could not be realized.In order to solve the contradiction that power line maintenance required to cut off power while user power supply required not,the so-called"non-interruption maintenance technology"at that time came into being.
In 1953,workers of the former Anshan Electric Power Bureau began to study simple tools for live cleaning,replacement and disassembly of power distribution equipment and leads.On May 12,1954,in the mass movement of technological innovation,Liu Changgeng,a technician of Anshan Electric Power Bureau,came up w ith a method of live removing and binding distribution porcelain bottle binding w ires,showed tools he had developed,such as insulated tongs,insulated clip scissors,porcelain insulator cable clip,etc.,and put forward technical analysis report and operation scheme of live replacing straight w ire pole,porcelain insulator and cross arm of 3.3kV line.
Live replacement of items like cross arm,wooden pole and porcelain insulator of 3.3kV distribution line was successfully completed on the scene by using tools fabricated w ith wood similar to birch wood bar.His technical innovation was recognized by experts and passed the feasibility study.
The date,May 12,1954,was recorded in the annals of Anshan Electric Power Bureau as the founding day of live working,and also recorded in the history of electric power development in China as the beginning of development of live working in China.
Live working was highly valued by leaders of Anshan Electric Power Bureau,and in order to consolidate and develop initial achievements of live working,Anshan Electric Power Bureau formally established a professional team of live working in June 1956,w ith Zhang Renjie as the team leader,and Liu Changgeng as the specific engineer.It was further developed to live replacement of wooden straight w ire pole,cross arm and insulator of 44-66kV line.
The first generation of tools have the follow ing characteristics:the main insulating tools are made of porcelain insulator and porcelain bushing,and the metal parts are made of ordinary steel and malleable cast iron,which makes the tools and instruments bulky and insufficient in universality.As shown in Fig.1-1,the first generation of"rise and fall"tool is used for live replacement of a straight wooden pole of 66kV line,and in Fig.1-2,the first generation of"insulated splint"tool is used for live replacement of a strain insulator string of 22-33kV line.
Fig.1-1 Live Replacement of a Straight Wooden Pole of 66kV Line
Fig.1-2 Live Replacement of a Strain Insulator String of 22-33kV Line
2.Second Stage of Development of Tools and Instruments for Live Working
In October 1957,the former Northeast Electric Power Bureau designed the first set of tools for live working for 220kV high-voltage transmission line,and successfully applied them to live working of 220kV high-voltage transmission lines.At the same time,the complete set of maintenance tools for 3.3-33kV wooden pole and tower line had also been improved and perfected,which laid a material and technical foundation for the implementation of non-interruption maintenance of lines at all voltage levels.
In 1958,the current Shenyang Central Test Institute started the experimental study on the maintenance with human body directly contacting with conductors.On the basis of learning from foreign experience,they solved the shielding problem of high-voltage electric field,and successfully carried out the first equipotential experiment of human body directly contacting with 220kV live conductors in the test field.The experimenter was Liu Dewei who completed the task of equipotential operation and conductor repair on 220kV line for the first time.The success of this equipotential live working experiment opened a new chapter of live working in China.Since then,equipotential operation technology has been widely used in live working in China.
Fig.1-3 is the picture of 220kV equipotential experiment conducted by Anshan Electric Power Bureau in 1958,and Fig.1-4 is the operation of removing lead wire of 220kV arrester conducted by Anshan Electric Power Bureau in 1958.
Fig.1-3 220kV Equipotential Experiment
Fig.1-4 220kV Operation of Removing Lead Wire of Arrester
Around 1959,Anshan Electric Power Bureau developed a set of tools and operation methods for non-interruption maintenance of transformer equipment on the basis of 3.3-220kV outdoor power transmission and distribution equipment.Till then,China's live working technology had developed into a 3.3-220kV comprehensive maintenance technology integrated with transmission,transformation and distribution.
In March 1958,the former Electric Power Bureau of Liaoning Province held a conference on non-interruption maintenance of lines in Anshan,after which the live working technology began to be popularized in power supply departments of Liaoning Province and northeast electric power system.On April 12,1958,the People's Daily reported the success of live working technology experiment in Anshan Electric Power Bureau under the title of Major Technological Innovation in the Electric Power Industry-Non-interruption Maintenance of Electric Power Lines.From May 20 to July 1 of the same year,46 technical representatives from power supply departments of Beijing,Shanghai,Hubei,Sichuan,Shaanxi and other provinces and cities received technical training on live working in Anshan.In that year,more than 5700 representatives from associate units visited Anshan to learn the live working technology.
The second generation of tools and instruments for live working used in 1957-1960 have the following characteristics:the main insulating tools are made of phenolic wood laminate,phenolic rubber paper tube,phenolic cardboard and silk,and the metal parts are made of ordinary steel and malleable cast iron.The tools and instruments in this stage are bulky,with certain universality.
3.Third Stage of Development of Tools and Instruments for Live Working
In 1960,the former Liaoji Electric Power Bureau formulated the Specification for Safety Operation for Non-interruption Maintenance of High-voltage Overhead Lines which became the first instructional specification for live working in China.It marked that live working in China had been on the right track.During this period,the nationwide non-interruption maintenance work had shifted from simple technology promotion to the stage of innovation and development combined with local specific conditions and production tasks.In addition to indirect operation and direct equipotential operation,the maintenance method moved forward to water washing,explosion crimping,etc.Maintenance tools changed from original heavy tools such as support rod,pull rod and suspender to light tools and rope tools.The insulated rope ladder and insulated tackle block with oriental characteristics were also been widely used.The operation was marching towards complex projects,such as replacing conductor and overhead ground wire,moving tower and transforming tower head.
In November 1964,live maintenance performance was held in Tianjin,which had a positive impact on the promotion of these new technologies nationwide.
In 1966,the production office of the former Water Conservancy and Power Department held a national live performance conference for live working in Anshan,which marked the live working in China had developed into the stage of popularization,and also promoted the development of live working to a newer and deeper field.
In 1968,the former Anshan Electric Power Bureau successfully experimented the new method of entering 220kV intense electric field along the insulator string.Since it was very convenient to replace single insulator on the double strain insulator string by this method in certain conditions,it was quickly spread to the whole country.single insulator on the double strain insulator string in certain conditions,it was quickly spread to the whole country.
In 1973,the former Water Conservancy and Power Department held the second national experience exchange meeting on live working in Beijing.The technical group of this meeting put forward a discussion draft of related topics on live working safety technology,which laid a technical foundation for the formulation of national regulations for live working.(https://www.daowen.com)
Fig.1-5 Operation of Replacing Whole String of Strain Insulators of 220kV line
Fig.1-6 Equipotential Inspection on 220kV Line,Dealing with Defects such as Heat of Strain Lead Contact
Fig.1-5 shows the operation of replacing the whole string of strain insulators on 220kV line with the third generation of tools and instruments for live working(stringing pull rod and insulator cradle),and Fig.1-6 shows the equipotential inspection and handling of defects like heat of strain lead contact on 220kV line with insulated rope ladder.
The third generation of tools and instruments for live working have the following characteristics:the main insulating tools are made of epoxy glass cloth laminate,epoxy glass cloth pipe,glass wire drawing rod,nylon rope and silk rope,and the metal parts are made of alloy steel and malleable cast iron.In this stage,the weight of tools and instruments for live working was reduced and the universality was strengthened.
4.Development of Tools and Instruments for Live Working in Later Stages
In 1977,the former Water Conservancy and Power Department brought live working into the safety work regulations issued by the Department,which further affirmed the safety of live working technology.In the same year,China's live working personnel started international exchanges,participated in activities of the live working group of the International Electrotechnical Commission,and established a domestic working group with IEC/TC78 standard to work out relevant standards for live working.In May 1984,China Live Working Standardization Committee was established.
In 1979,the 500kV Yuanbaoshan-Jinzhou-Liaoyang-Haicheng Transmission Line was built in Northeast China.In order to ensure the safe and economic power supply after the 500kV Line was put into operation,the former Anshan Electric Power Bureau carried out the research on new technologies of 500kV live working.In order to solve this problem,retired employees such as Zhang Renjie and Ge Yuanchang were invited back to carry out the research work on live working of 500kV tangent tower and resisting-tensile tower.They fully carried forward the hardworking spirit in previous years,and made tools,conducted field tests and prepared operating procedures in person.In 1984,the research and development supporting work of 500kV partial live working routine items and tools were completed.Soon afterwards,working methods and tools and instruments for 500kV live replacement of linear insulator string and strain insulator string,and live repair of conductor,etc.were successfully developed as scheduled and entered the implementation stage.
In 2000,the former North China Power Grid Co.,Ltd.first studied and realized live working of 500kV compact line.Fig.1-7 shows the operation of Jinzhou Electric Power Bureau using"stringing pull rod-insulated trolley"to replace the whole string of strain insulators on 500kV Line in the 1980s;Fig.1-8 shows the operation of"entering intense electric field along insulator string"to replace 500kV single insulator in Northeast China.
Fig.1-7 Operation of Replacing Whole String of Strain Insulators of 500kV Line
Fig.1-8 Operation of Replacing Single Insulator of 500kV Line
In the 1990s,China introduced aerial devices with insulating booms,which solved many problems that perplexed live working of distribution lines.At present,aerial devices with insulating booms have been widely used in live operation of distribution lines,and the localization of aerial devices with insulating booms with the working voltage of 10-500kV has been realized.
In 2007,North China Power Grid Co.,Ltd.realized live working of 500kV line with helicopter after research,which reached the international leading level.Fig.1-9 shows equipotential operation with helicopter,and Fig.1-10 shows live washing operation with helicopter.
Fig.1-9 Equipotential Live Working with Helicopter
Fig.1-10 Live Washing Operation with Helicopter
From 2006 to 2009,Shanghai Municipal Electric Power Company of State Grid and Beijing Electric Power Corporation of State Grid researched and implemented non-interruption operation methods of 10kV distribution line.
From 2008 to 2009,Northwest Power Grid researched and implemented live working of UHVAC 750kV line.Central China Power Grid and North China Power Grid began to research and implement live working of UHV 1000kV line,tools and instruments for live working of±500kV and±800kV transmission line as well as project implementation.
On April 14,2009,the first UHV live line defect elimination operation carried out by Hubei UHV Power Transmission and Transformation Company in China was successfully completed on 1000kV Nanjing LineⅠ,as shown in Fig.1-11.
On June 11,2009,the world's first±800kV UHV DC transmission live working was successfully completed by 7 professionals(including Hu Guang)of Hubei UHV Transmission and Transformation Company.This live working operation used self-developed tools and instruments for live working,as shown in Fig.1-12.
Fig.1-11 1000kV UHV Equipotential Defect Elimination Operation
Fig.1-12 ±800kV UHV DC Transmission Live Working