4.2.4 Precautions for Use of Bypass Work Vehicle a...
1.Bypass Work Vehicle
(1)Bypass work vehicle is a special transport vehicle for the transfer bypass equipment,with high cost,and it is necessary to strictly prevent the vehicle from being crushes and bumped during transportation and use.
(2)Special personnel shall be designated for the bypass work vehicle,and shall not be operated by the untrained or licensed personnel.
(3)During parking and using,the hydraulic auxiliary legs should be supported in time to avoid deformation and damage of the wheel load.(https://www.daowen.com)
2.Load Switch Vehicle
(1)In order to make the bypass load switch and the bypass flexible cable easy to connect,the external interface shall be plug-in interface,which is easy and reliable to connect.The indicative marks for closing and opening of the switch shall be clear and obvious.No matter the manner by which the switch is closed,it is necessary to lock after closing.It is strictly forbidden to open the switch without operation and without any measures.It also has a pressure display and a decompression locking device.
(2)The bypass load switch has a nuclear phase function,so that the voltage on both sides of the switch can be phased in the opening position to avoid phase-to-phase short circuit caused by incorrect phase sequence closing during bypass circuit assembly.Otherwise,the bypass load switch shall have a terminal for checking the nuclear phase function,and the terminal voltage shall be no more than 800V.The phasing device or phasing detector must be provided with obvious in-phase or out-of-phase indication signals,audible alarm signals,etc.
(3)When the power side bypass load switch is pulled off,the bypass load switch is disconnected by the capacitor current of the no-load bypass cable,that is,the charging current.The charging current of the no-load cable is related to the length,wire diameter,voltage,etc.of the cable.According to the testing analysis of the China Electric Power Research Institute,when the single-core(phase)cross-sectional area of the cable line is not more than 300mm2 and the length is not more than 3km,the maximum single-phase steady-state capacitive current that is disconnected should be 5A.In general,the length of the overhead bypass work line is relatively short,and the cross-sectional area of the bypass flexible cable is also small,generally 35 to 50mm2.In this case,when the power side bypass load switch is opened,the disconnected charging current should be much less than 20A.Therefore,the life of the bypass switch cannot be simply measured by the number of times the load current or the charge current is disconnected.Of course,it is not equivalent to the mechanical life and its life is also related to the use,preservation and maintenance.