For oil-consuming electric power equipment, their protection and condition monitoring are dependent on the real-time test of its oil’s various performance, for which impedance spectroscopy (IS) provides a potentially efficient technology. Therefore, the current situation and prospect of IS and its application in Electric Power Equipment Oil (EPEO)’s performance test are reviewed in this paper. First, IS is introduced from new classifications of univariate IS and multivariate IS, the current problems in EPEO’s performance test are summarized, and for solutions to these problems, the principle of why a matter system’s various properties can be tested by IS and IS’s advantages and application potentials are analyzed. Then, IS’s development status in impedance spectrum’s measurement and acquisition, analysis and processing, and industrial application is summarized, and its implementation scheme and key problems in EPEO’s performance test, including the construction of impedance spectrum’s measuring system, the analysis and processing of spectrum data, and the representation and derivation of EPEO’s performance, are also provided. Finally, it is pointed out that (1) the pursuit of high-precision, rapid, miniaturized, and multivariate impedance spectrum measuring technology and instruments; (2) for impedance spectrum analysis and processing, the mining of in-depth information, construction of new object models, processing of the impedance spectrum under nonlinear or even unstable conditions, and the analysis of multivariate impedance spectra; (3) the development of industrial applications in depth and breadth are IS’s future trends.
