Requirements for a modern PQ and DFR monitoring systemPQ monitoring case study in Portugal

Abstract

There are many manufacturers around theworld providing power quality (PQ) monitoring and digitalfault recording (DFR) solutions. Different monitoringrequirements, monitoring practices, and newstandardization make for a diverse range of availablesolutions. The first section of the paper will summarize therequirements and challenges of a modern PQ and DFRmonitoring system. The second section will be a case studyabout the Qualitrol and QEnergia’ systems implemented inPortugal, particularly at EDP and REN; it will show whathas been done.Until IEC 61000-4-30 [1] was introduced in 2003 manypower quality parameters were not well defined leading tosituations where different instruments produced differentresults. In 2008 Edition 2 was introduced and Edition 3 isnow in progress.As well as considering 61000-4-30, this paper willsummarize the key requirements of the new upcoming IEC62586 [2] product standard for power quality monitoringdevices.In the second section of the paper we will present how tomanage grid measuring points whose characteristicschange over time, rather than just manage a fleet ofmeasuring instruments. We will discuss the way to makecompatible different types of measurement devices, accessdifferent data sources, handle the standards changes bothin the limit values and in the way values are calculated andvalidate PQ and event data.Different ways of representing power quality informationwill also be addressed. Presenting information and not justraw data from the monitoring system is essential forefficient management of reports for regulatory and thirdparty use.The Qualitrol and QEnergia’s systems at EDP and RENhave been developed to suit existing communication infrastructure, automatic and manual data retrieval andintegrate in a single software analysis package, in a multivendor way, already existing older PQ devices togetherwith new instruments. Combining PQ and DFR data alsoleads to efficiencies when collecting and analyzingresults.