Abstract: A method of analyzing characteristics and adjusting parameters of cable type linear thermal fire detector is proposed to achieve performance status discrimination.Firstly,on the basis of studying the equivalent circuit of cable type linear thermal fire detector,the variation characteristics of insulation resistance of cable type linear thermal fire detectors with temperature and humidity is analyzed.Then a temperature resistance characteristic model for cable type linear thermal fire detector is established.A performance discrimination method is proposed,which divides cable type linear temperature fire detector into three states (excellent,good,and unqualified),and provides processing methods for these three states.Finally,a set of temperature resistance characteristic analysis device for cable type linear temperature fire detector is developed and it′s applied on site at a 1 000 kV ultra-high voltage substation.The results show that the device can accurately distinguish the performance status of cable type linear thermal fire detector,and significantly reduce false alarms during actual using.

Key words: cable type linear thermal fire detector, characteristic analysis, performance states, discriminant methods, parameter adjustment