With the development of distribution network and the increase of power cable lines, the capacitor current of ungrounded system increases sharply, which seriously threatens production safety. To this end, our company has developed a complete set of arc suppression pressure limiting line selection device, when single-phase grounding current is induced in grid, earth capacitance current compensation power grid, the grounding current of fault point as monomer casting nylon values significantly decrease the residual current, reduce the arc grounding fault phase voltage recovery after zero velocity. By prolonging the recovery time of fault phase voltage, avoiding the reburning of grounding arc and realizing full arc extinguishing, many technical casting problems such as real-time on-line monitoring of capacitor current, automatic tracking compensation and overvoltage suppression in resonant grounding system have been successfully solved. At present, there are technical problems in the selection of overvoltage protector in this set of equipment, which are expected to be solved. 1) The bearing involved in this special technology is the bearing used for the drive roller of the sector section of the continuous caster in the metallurgical department of the steel plant, which is basically monopolized by foreign brands. The technical support required for bearings is as follows: (1) optimize the structure and main parameters of bearings; ② selection of bearing manufacturing materials; (3) Ring crack fracture gap and structural design; ④ efficient, reasonable and convenient patent fixture design method; (5) Study the test method of subdivided bearings. The high bearing capacity of CARB bearings allows up to 10 times the allowable Angle alignment error of short cylindrical roller bearings, tapered roller bearings or needle roller bearings, up to 0.5°. The metal casting bearing of CARB shaft has high reliability and long service life, and it is widely used in the guidance of continuous casting machine (namely roller bearing with fan support) in steel mills. The required technical support includes :① the optimization design of the main parameters of the bearing; ② Research on bearing detection technology.