| Utilizing live working platform for live maintenance can reduce the loss caused by outage maintenance and provide better safety assurance for live working operators.However,when it is tough to meet the constraints of minimum approach distance and the complex gap due to the narrow live working space,the design of live working platform in substations turns into a technical difficulty.At present,calculation methods that relate the complex gap with the structural parameters of live working platform and the flow parameters are rarely discussed in the relevant papers.Besides,there is a lack of research on the operational safety of workers availing themselves of live working platform in substations.Therefore,under the task of developing live working platform for 330 k V substation in Fuping,this paper focuses on the influence of electric field on the platform design and operational safety.Primarily,in order to ensure the insulation distance,this paper puts forward a structural scheme to achieve lifting through automatic assembly and disassembly of insulation modules,and part of the structural parameters’ design values such as the width of the vehicle are given according to the technical parameters like load-carrying capacity.In addition,a weighted digraph model is constructed with spatial conductors as elements of vertex set and distances between conductors as elements of weight set.According to the structural scheme,the minimum approach distance as well as complex gap are related with the structural parameters and flow parameters through the weight set of the weighted digraph.Applying the method of calculating the minimum weight set of weighted digraph and the shortest path between the high-voltage node and the ground potential node,the feasible region of flow parameters and the design values of structural parameters satisfying the constraints of minimum approach distance and complex gap are acquired under the conditions of driving,lifting,translational and equipotential working conditions.So as to verify the reliability of the design parameters and process parameters obtained,an equivalent experimental platform was built.By means of measuring 50% switching impulse discharge voltage,the calculated risk rate is less than 10-5,which meets the requirements of operational safety.Furthermore,via finite element simulation,from the point of view of the operational safety of live maintenance personnel,the distribution of electric field intensity on human body surface under different working conditions,different working locations,when operators are in different postures as well as in different material buckets is analyzed.Based on the analysis,the maximum surface field intensity of live working operators appears at the equipotential condition,which is 18 k V/cm.Referring to the relevant standards,the protective suggestion that live maintenance personnel should wear at least 42 d B shielding clothing is given.Finally,from the point of view of structural safety,the critical speed that avoids the first mode of breeze vibration in cross-wind direction is 6.7m/s.Under circumstances when the wind speed instantaneously increases but does not exceed the critical wind speed,the response characteristics of the live working platform along the wind direction are analyzed by modal superposition method. |
