Study On The Single-phase Ground Fault Limiting Measures Of 10KV Distribution Network In A Steel Plant

This paper studies and analyzes the proble ms existing in the practical treatment of single-phase ground fault of 10 k V distribution network in an iron and steel plant.The specific contents are as follows:A steel plant has been put into operation for more tha n more than 10 years.All kinds of electrical equip ment are affected by ma ny factors,such as product ma nufacturing level,daily mainte nance,maintenance quality,e quip ment operation environment,etc.In case of unstable arc single-phase ground fault in 10 k V power distribution network in the plant area,during the period when the operator on duty is looking for the specific ground point,the arc ground over-voltage generated on the no n fault phase can be up to 3-4 times of the phase voltage,which causes weak insulation of other equip ment to click through,and the single-phase ground fault develops into p hase to phase short-circuit fault or different phase to ground fault of different equipme nt,so as to expand the scope of fault influence It causes the voltage fluctuation of power system in iron and steel works,which is very harmful to the operation of power syste m in iron and steel works.In order to solve the dama ge of arc grounding over-voltage to the insulation perfor mance of electrical equip ment in 10 k V distribution network,the arc extinguishing mode of 10 k V distribution network in iron and steel plant is analyzed by using ne utral point and arc suppression coil.The arc suppression coil's over-voltage suppression ability to arc grounding can no longer meet the production and operation requirements,so the existing arc extinguishing technology needs to be upgraded and transformed to meet the safety and stability requirements of distribution network.Based on the research and analysis of arc suppression and line selection in the case of single-phase grounding fault of 10 k V distribution network in the substation of iron a nd steel plant,the fast grounding transfer de vice is installed on the 10 k V two sections of buses in the main raw material drop substation respectively,which can effectively restrain the arc grounding overvoltage and effectively s uppleme nt the existing arc suppression c oil grounding co mpensation mode.The actual operation results show that the device and arc suppression coil carry out grounding compensation together,effectively limit the non fa ult phase line voltage to a level slightly higher tha n the normal operation line voltage,solve the threat of arc Overvoltage on electrical equipme nt and operation safety,protect the insulation perfor mance of electrical equipment,and improve the reliability of 10 k V distribution network power supply.With the introduction of the power frequency transient current acquisition method and the ma ximu m increment method,the sensitivity,reliability and accuracy of the small current grounding line selection device are improved.