In year 2007 or 2008,electromagnetic loop circuits of the north power network of Henan will not be opened,this paper try to find some problems by researching on loads,power network structure;then try to study the infection of some serious faults,for example,the bus fault,the switch malfunction,or N-(1+1) faults,and so on;and check against network s safety and stability.

This paper introduces the configuration of bus protection in dual-bus dual-subsection connection,and puts emphasis on analysis of action of bus differential protection in bus coupling breakers or sectional switches malfunction and dead-zone fault,and also expounds the differences between bus coupling breaker malfunction and sectional switch malfunction.

Analysis of open circuit failure of chip resistors.;

Analysis on fissuring failure of H13 steel in warm extrusion die cavity and control measurements;