Identification The Critical Heating Of Supply Conductors From A SIEMENS WL I 800 N Automatic Circuit Breaker

This paper presents an application that determines and processes the temperature increase and the heat dissipation inside an insulated copper conductor of a given section as function depending on the applied conduction current from a SIEMENS WL I 800 N automatic circuit breaker. The application was made with a programmable automation CPU 1215 PLC, analog extension module SM1245 and operator interface TP 700 Comfort (Siemens). The current output is transmitted from the circuit breaker to the PLC using an analog module interface. The determination of the temperature is done indirectly by measuring the conduction current by a current loop 4–20mA generated by the CB interface. The processing of the instantaneous values of the conduction current is carried out by connecting the output module to the analog input port of the extension module having a 10 bits resolution of the analog-digital conversion. The measurements performed will allow the introduction of pre-alarms that will be useful for the maintenance of the installation served by the automatic circuit breaker.