Chapter 5 by Ma reviews measurement and monitoring technologies for electrical power systems concentrating on characterization of metallic material, condition monitoring of insulation and condition monitoring of associated assets.
The chapter focuses on insulation degradation and its measurement and discusses the thermal, mechanical, and electrical stresses that lead to degradation. Defect formation is highlighted, which can lead to partial discharges in operation. It is the interaction of thermal, mechanical, and electrical stresses on defects that increases the probability of partial dis¬charge activity and eventual failure of the system. Thus, Ma makes the case that it is imperative that partial discharge in such systems is detected at an early stage for a quick remedy.
Ma extensively discusses the different approaches to partial discharge detection and measurement. A particularly helpful section is on noise issues and denoising of measurements. Partial discharge measurements can often be immersed and lost by electrical noise and require noise reduction techniques that fall into two categories:
1.Specialist hardware—purpose-built circuits, and
2.Specialist software—purpose-built signal processing techniques.
A selection of these circuits and techniques is discussed in detail. An example using a wavelet-based technique is presented and proves to be impressive.