Systems and methods for assessing cable insulation

A method for nondestructively assessing cable insulation age-related damage without contacting the insulation but measuring through the outer jacket;

• the method comprising:
• engaging a first (narrow) tine gap interdigital capacitor assembly engaged with a first portion of the exterior of the cable jacket, the first tine gap interdigital capacitor assembly comprising a first electrode, and the engaging comprising aligning the first electrode on the exterior of the cable jacket;
• determining a first capacitance or dissipation value of the jacket and insulation using the first tine gap interdigital capacitor assembly;
• engaging a second (wide) tine gap interdigital capacitor assembly with a second portion of the exterior of the cable jacket, the second tine gap interdigital capacitor assembly comprising a second electrode, and the engaging comprising aligning the second electrode on the exterior of the cable jacket;
• determining a second capacitance or dissipation value of the jacket and insulation using the second tine gap interdigital capacitor assembly, wherein the first and second tine gap interdigital capacitor assemblies have different gap widths and corresponding depths of field;
• and
• estimating capacitance or dissipation factor of the cable insulation using a calibrated regression model, wherein said estimating includes calibrating the regression model by determining 2-factor linear regression coefficients of the regression model based on the first and second values.

A system for assessing cable insulation age-related damage, the system comprising:

• a cable jacket encompassing cable insulation and conductive material;
• at least two tine gap interdigital capacitor assemblies engaged with and residing upon the exterior of the cable jacket;
• and
• a first tine gap interdigital capacitor assembly configured to engage with a first portion of the exterior of the cable jacket, the first tine gap interdigital capacitor assembly comprising a first electrode, and the engaging comprising aligning the first electrode on the exterior of the cable jacket;
• a second tine gap interdigital capacitor assembly having a different gap width than the first tine gap interdigital capacitor assembly and configured to engage with a second portion of the exterior of the cable jacket, the second tine gap interdigital capacitor assembly comprising a second electrode, and the engaging comprising aligning the second electrode on the exterior of the cable jacket;
• processing circuitry operatively engaged with the capacitor assembles and configured to:
• determine a first capacitance or dissipation value of the cable insulation using the first tine gap interdigital capacitor assembly;
• determine a second capacitance or dissipation value of the cable insulation using the second tine gap interdigital capacitor assembly;
• and
• estimate capacitance or dissipation factor of the cable insulation using a calibrated regression model, wherein said estimating includes calibrating the regression model by determining 2-factor linear regression coefficients of the regression model based on the first and second values.