Modeling Insulation Leakage Effects on Platinum Resistance Thermometer Performance

The purpose of this paper is to discuss electrical leakage in the insulating material of typical platinum resistance thermometers (PRTs) and how it can be modeled to understand its effect on PRT measurement. The paper will present comprehensive background information regarding PRT insulation leakage, what it is, how it is caused, and how it affects PRT measurement. To model the effect on PRT measurement, the insulating materials and sensor circuit in a typical PRT are transformed into an equivalent electrical circuit that is analyzed using SPICE circuit analysis. Detailed diagrams, including equivalent electrical schematics, are used to fully describe the subject. The outcome will provide awareness to PRT users to know how to identify and understand insulation leakage and its effects. It will also demonstrate how to monitor PRTs for insulation leakage and what steps should be taken to prevent measurement errors.