| UHVDC Transmission Lines have the advantages of large transmission capacity,long transmission distance,low loss,high reliability of operation,and few opportunities for power outages and maintenance.It has become an important part of the State Grid and plays an increasingly important role.With the construction and operation of ±800k V DC Transmission Lines in china,new requirements have been put forward for are put for the technical research of live operations,including the selection of equipotential method and optimal path,potential transfer mode and optimal transfer distance of UHV DC Transmission Lines,which has become a research hotspot in this field.Therefore,it is necessary to carry out in-depth and systematic research on the optimal path and the optimal distance of potential transfer for UHV DC Transmission Lines.Therefore,the following researches are carried out in this thesis:(1)According to the several postures commonly used by the workers when using the hanging basket method for live work and referring to the standard size of males between 26 and35 years old in "GBT10000-88 Chinese Adult Human Body Size",this thesis establishes the corresponding human body model.At the same time,the corresponding linear tower model and wire model are established according to the actual parameters of the linear tower of ±800k V DC transmission line,and the simulation models of several typical positions of live working are given.(2)For the worker to use the hanging basket method to enter the equipotential,the safety distance,combined gap and discharge hazard rate at any position in the plane area surrounded by the tower body,crossarms and pole conductors are studied.The reliability and safety of using the hanging basket method to enter the equipotential are verified from these three aspects.It is concluded that any position in the plane area can ensure the personal safety of the worker.(3)The COMSOL finite element simulation software is used to simulate the distribution of the electric field strength on human body surface at the typical positions of the ground potential,intermediate potential,and equipotential of live working.According to the calculation formula of the shielding efficiency,the safety protection measures should be taken when entering the equipotential.At the same time,combined with the FLOYD algorithm,the optimal path is calculated for the worker to enter the equipotential from the linear tower body and crossarm of the ±800k V transmission line using the hanging basket method.(4)The electromagnetic transient simulation software PSCAD is used to calculate the transfer current and transfer energy at different potential transfer distances.The potential transfer method and the optimal potential transfer distance of ±800k V DC transmission line are obtained. |
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