| With the rapid growth of China’s electricity supply,more transmission lines need to be built,leading to increasingly prominent contradictions between line construction and land resources issues.Although the 500 kV compact tower tower on the same tower double-circuit transmission line can solve the problem of scarcity of land resources,due to its compact three-phase conductor distribution and unique insulator connection method,the live replacement of insulators has its own particularities.In order to solve the problem of live replacement of insulators caused by the combination of compact 500 kV and double-circuit transmission technology on the same tower,it is imperative to study key technologies.In combination with the 500 kV conventional line live replacement insulator technique,according to the compact characteristics of the tower form and the specific tower type and insulator string connection characteristics of the double-conductor multi-conductor tower layout,the possible use of the traditional replacement insulator technology for this special tower type was studied.Security risks.Based on the detailed analysis of personnel,equipment,environment,electrical potential,and maintenance tools,we identified two key technologies for entering the equipotential method and the special fixtures for live replacement of insulators as live replacement insulators for 500 kV compact double-circuit transmission lines on the same tower.The study is as follows:1)According to the compact three-phase arrangement of a 500 kV compact double-circuit tower on the same tower and the tower’s compact three-phase arrangement,and different jumper arrangements on the tower,the analysis of several working positions in the potential path of equipotential workers,Calculate the minimum combination gap,and verify whether the operator meets the minimum combination gap based on the calculation results,and finally put forward a reasonable path into the equipotential.2)A three-dimensional model with a physical dimension of 1:1 ratio of a linear tower and a tension tower of a 500 kV compact double-circuit tower on the same tower has been established,aiming at the typical working of the conductors entering the upper phase and the lower phase conductors for the path conditions of the workers entering the three-phase conductors.The location simulations were performed to obtain the amplitude and distribution of the field strength on the human body surface,thereby determining the safety of entering the equipotential path and proposing reasonable suggestions for safety protection measures.3)According to the actual working conditions and safety standards for the replacement of live working of insulators,the maximum permissible load of fixtures is obtained,and in combination with the standard specifications for fixture design,fixture manufacturing materials and fixture structures that are more in line with practical requirements are designed.After checking the mechanical strength and electric field strength of the new type of fixtures designed,after confirming safety,special fixtures for live replacement insulators that meet the engineering requirements were developed.4)Taking the live work of the 500 kV Yuxing first loop as an engineering application example,the climbing ladder method was used to enter the upper phase conductor of the straight tower,and the developed upper and lower flower cards and airfoil cards were used to complete the string insulator string in the straight tower.The live working replacement of the tension tower insulator string is performed.The practical application of engineering shows that the two key technologies proposed in this paper can well meet the actual engineering needs and have a wider application prospect. |
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