Condition-based monitoring and prognostic health management of electric machine stator winding insulation

Abstract

A comprehensive diagnostic and prognostic method is introduced for assessing the condition of stator winding insulation and predicting its failure time. A diagnostic method is developed by building an analytical model of the stator winding. Degradation is simulated by altering the permittivity and conductivity of the insulation in a finite element model simulation and changing the analytical model accordingly. The diagnostic method is performed with an oscilloscope and other common hardware. A prognostic method is introduced which is used to predict the remaining useful life of the insulation based on fitting insulation current measurements to an exponential decay model. The diagnostic method is verified with the analytical model for multiple levels of degradation and experimentally for the healthy case. The prognostic method is verified with simulated degradation data.

Failure prognosis methods in electrical drives - State of the art and future directions

“…A commonly used one model is the Paris-Erdogan [28,35], • insulation degradation is generally considered to be due to aging and increased temperature and follows the Arrhenius model [36], • models for the aging of electronics include thermal and voltage stresses and the physics associated with them; a number of reviews exist, e.g. [7,37].…”

“…Prognosis based on on-line measurement is feasible, but only recently methods such as those in [46] have been attempted, e.g. [36].…”

Using Leakage Currents to Evaluate the Induction Motor Insulation Condition

“…Поэтому желательно иметь такие методы мониторинга состояния изоляции, которые позволили бы прогнозировать это состояние. В работе [10] путем математического моделирования показано, что имеется возможность отслеживать старение изоляции по изменению емкостных токов утечки, а в работе [11] это было доказано экспериментально при проведении исследований по ускоренному термическому старению изоляции статора низковольтного асинхронного двигателя. Эти исследования показали, что емкостные токи утечки со временем экспоненциально изменяются по мере старения изоляции, что создает возможности не только отслеживать текущее состояние изоляции, измеряя емкостной ток утечки, но и прогнозировать это состояние.…”

The Impact of Thermal Degradation on Properties of Electrical Machine Winding Insulation Material

“…Alternatively, other researchers have tried to understand directly the physical mechanisms that lead to insulation degradation [18], leading to lifetime prediction and machine life prognosis models that may be used to improve performance and reduce cost. It is now well known that there are many different ageing stresses: electrical, thermal, mechanical, humidity, moisture etc [19].…”