Dielectric Loss Tester is often referred to as "tan delta tester" or "tester"
Dielectric Loss Tester, often called "tan delta tester" or "tanδ tester", is a specialized precision instrument used in power systems to measure the dielectric loss tangent (tanδ) and capacitance (C) of insulating materials in high-voltage electrical equipment. It is one of the most sensitive means to judge whether the insulation of electrical equipment (such as transformers, instrument transformers, bushings, arresters, capacitors, etc.) is damp, aged, or deteriorated. In the 2026 power operation and maintenance standards, it remains the core equipment for preventive tests. 1. Core concept: What is dielectric loss (tanδ)? When an AC voltage is applied to insulating materials, a tiny leakage current is generated in the insulator. This current can be decomposed into two components: Capacitive current (
