Fast Estimating Method of Effective Life of Power Cable in Industrial Environment

With the wide and ever-increasing application of non-linear loads, such as variable speed drives, personal computers, compact fluorescent lamps (CFL), arc furnace transformers and high frequency electrical heaters, power quality of the supply is severely disturbed. Low power quality means introduction of higher order harmonic frequency, harmonic current and harmonic voltage in supply system. These harmonics result in unbalance in a three-phase system and this causes a considerable amount of I2R loss in the cable and increases the cable resistance. Increment of r. m.s current and cable resistance results in the increment of joule losses of the cable. This paper describes a method of determining cable temperature rise with respect to harmonic current present in the system and this helps to estimate the remaining service life of the power cable. The proposed method helps to determine the effective life of cable and thus reduce insulation failure rate. The proposed method also helps to increase reliability of supply system for critical process industry.