New Power Quality Assessment Criteria for Harmonic Disturbances

This chapter presents an overview of the main disturbances affecting the electrical power system operation. It also investigates the harmonic issues and outlines the contents of the major international standards in this context. The problem of controlling power quality is becoming more relevant because of the widespread use of non-linear and time-varying single-phase or three-phase loads. These affect the operation of distribution networks in residential, commercial, and industrial areas. Power quality deterioration is due to transient disturbances and steady-state disturbances. This chapter describes the main causes of such disturbances as well as the detrimental effects they have on the electrical systems. Some definitions relevant to non-sinusoidal systems are also presented. The chapter then outlines the International Electrotechnical Commission (IEC) and Institute of Electrical and Electronics Engineers (IEEE) Standards guidelines, which deal with harmonic disturbances. It emphasizes that the responsibility for the power quality deterioration should be shared between the supplier and the customer. Such information can be provided by indices in a straightforward and simple way. However, the traditional indices used by the international standards cannot satisfy these specifications. In this context, the chapter provides discusses a new index to evaluate the harmonic distortion phenomena in the supply electrical networks.