| As China’s energy bases and power load centers exhibit the characteristics of east-west distribution,it is an inevitable trend to build UHV HVDC transmissions with long-distance and large-capacity characteristics in order to ensure that electricity keeps pace with the rapid socio-economic development.The ±1100kV UHVDC transmission project is currently being constructed in China as the highest voltage level in the world.The inevitability as a skeleton of the power grid determines that outage maintenance for ±1100kV transmission line is very difficult.However its associated operation standards for live working have not yet been established.Once the ±1100 kV UHVDC transmission line is put into use,it will face the risk of live working at any time.Therefore,this article has carried out the research on the live working technology of ±1100kV UHVDC transmission lines in order to provide the basis for the optimization design of line insulation and the technical standards of live working safety.Firstly,based on the calculation principle of the dangerous rate of live working and altitude correction,this paper studied the minimum safety distance of the typical working positions during the live working process for the ±1100 kV UHVDC transmission line tower and the tension tower,the typical operation positions include the tower ground potential,side towers and wires,etc.,which provide technical support for the actual live working of ±1100kV UHVDC power transmission in the future.Secondly,according to the characteristics of ±1100kV UHVDC transmission lines,the potential equipotential modes adopted by the straight tower and the tension tower are analyzed and compared,and the detailed process simulation analysis is performed.The best suitable mode for the tower type is recommended.In addition,this article carried out the test of a true-size tower head.According to the process of equipotential entry and exit recommended in this paper,the minimum combined clearance needed for live working was calculated.Thirdly,this paper analyzes the influence of electric field on human body from the perspective of strong electric field,leakage current and audible noise,and then the electromagnetic field simulation software ANSYS is used to simulate and calculate the surface electric field of the live working personnel at the typical working position of the ±1100kV UHVDC transmission line straight tower.And the three indicators in the course of live working of ±1100kV UHVDC transmission lines are studied through the way of experimental measurement.And then combined with ±1100kV live working safety protection appliances,the safety protection measures for live working of ±1100kV UHVDC transmission lines are studied.Finally,the evaluation indicators for the safety of live working in UHV are analyzed based on the fuzzy layer method and fiuzzy comprehensive evaluation method,and a safety evaluation system for UHV live working is established with the framework of live working environment,on-site operation management,comprehensive management of safety operations,quality of live working personnel and equipment management and safety protection.The UHV live working safety evaluation system has verified the applicability by using an example of replacement of spacer spacers on ±1100kV UHVDC Transmission Line... |
