Electrical-Based Diagnostic Techniques for Assessing Insulation Condition in Aged Transformers

• Main Authors: Issouf Fofana, Yazid Hadjadj
• Format: Article
• Language: English
• Published: MDPI AG 2016-08-01
• Series: Energies
• Subjects: power transformers; diagnostic techniques; insulation condition; transformer aging; partial discharge (PD); return voltage (RV); dielectric response; dielectric dissipation factor (DDF); dielectric response analysis; mechanical or electrical integrity of the core and windings
• Online Access: http://www.mdpi.com/1996-1073/9/9/679

The condition of the internal cellulosic paper and oil insulation are of concern for the performance of power transformers. Over the years, a number of methods have been developed to diagnose and monitor the degradation/aging of the transformer internal insulation system. Some of this degradation/aging can be assessed from electrical responses. Currently there are a variety of electrical-based diagnostic techniques available for insulation condition monitoring of power transformers. In most cases, the electrical signals being monitored are due to mechanical or electric changes caused by physical changes in resistivity, inductance or capacitance, moisture, contamination or aging by-products in the insulation. This paper presents a description of commonly used and modern electrical-based diagnostic techniques along with their interpretation schemes.