Surveying supply reliability and voltage quality at Italian customers

While outages and voltage quality problems are today main concerns and highly affect electric customers, nevertheless reports on effects of Power Quality (PQ) events are not yet well documented and there are still few estimates of PQ-related costs to the national industrial segment economy. For this reason a survey activity focused on assessing PQ in the industrial customers' segment of end-use was promoted within a wide Italian research project (called “Ricerca di Sistema” and supported by the Italian Ministry of Productive Activities with the aim to get benefits for the customers of the Italian Power System; it is worthy of note that the activities connected to this project are considered of public interest and are therefore financed from a specific item in the electric bill of not eligible customers). This survey is mainly aimed at identifying power quality levels at demand-side throughout the Country and collecting information about PQ costs, according to the industrial customers' point of view. The survey method was based on a questionnaire, providing the approach of asking customers about their reliability experiences and perceptions. In the questionnaire, both the main topics of PQ were clearly addressed: voltage continuity (or supply reliability), related to power supply outages, and voltage quality, related to low frequency disturbances (or voltage deviations from an ideal waveform) reaching equipment through the electricity supply. The paper presents, comments and discusses the main survey results, with special emphasis to the PQ related costs.