Analysis And Countermeasures Of 10kV Switchboard Malfunction In Zhuhai Distribution Network

With the development of the power industry reform, the applicationsof 10 kV high-voltage switchgears(HVSs)are also becoming wider and wider.The utilities pay more attention onthe repair and maintenanceof 10 kV HVSs. During recent years,the Zhuhai power supply bureau has donea great deal of researchabout the analysis and countermeasure of 10 kVhigh-voltage switchgears.On the basis of the statistical analysis of fault types of 10 kVHVSs,this thesis take focus on heating failures,insulation faults and transmission-mechanism faults of 10 k VHVSs.Themain reasonsand prevention measures of the failure areput forward. The details of the studies are given as follows.Firstly, the overall statisticaldata of 10 kV HVSfaults are analyzedto get the faulttypes and frequencies.The heating failure,insulation fault and transmission-mechanism fault are found as the three of the most common failures of 10 kV HVSs in Zhuhai grids.Secondly, for the heating failures,the main causes of the failure are analyzed the oretical calculation of temperature rising. The main causes of the heating failureincludethe poor contact of conductive parts and the improper selection of the conductivematerials. To prevent the heat failure,the non-contact wireless temperature measurement methodis appliedinto monitoring the temperature inside the switch cabinet.Thirdly, for the insulation faults,the recent insulation fault examplesof Zhuhai gridsare analyzed. The main reason resulting in insulationfaults is becauseof the weakinsulation abilityof electrical devices in the cabinet. Then the acoustic detection technique of partial discharge monitoring is applied to monitor insulation situation in the HVSs. The effectiveness of the approach are testifiedby the real results of the applications.Finally, for transmission-mechanism faults, theauxiliary earthingswitchin AEG switchgear is found as the position withthe highest failure frequecy.For preventing the transmission-mechanism faults,the structure of the auxiliary earthing switchis redesigned. The materials and implementation of the auxiliary earthing switchare discussed for the practical realization in the field.Anovel auxiliary earthingswitch is developed and put into operation.This thesisanalyzedthe fault data of HVSs and obtained the mainfault types in Zhuhai grids.The main reasons of HVS faultswere analyzed and the prevention strategies were given for threedifferent faults. Effectsof practical application show that the proposed measures can reduce the fault frequencies significantly.It provides important guidance for maintenance of 10 kV HVSs.