There are many manufacturers around the world providing power quality (PQ) monitoring and digital fault recording (DFR) solutions. Different monitoring requirements, monitoring practices, and new standardization make for a diverse range of available solutions.

The first section of the paper will summarize the requirements and challenges of a modern PQ and DFR monitoring system. The second section will be a case study about the Qualitrol and Qenergia’ systems implemented in Portugal, particularly at EDP and REN; it will show what has been done.

In the second section of the paper we will present how to manage grid measuring points whose characteristics change over time, rather than just manage a fleet of measuring instruments. We will discuss the way to make compatible different types of measurement devices, access different data sources, handle the standards changes both in the limit values and in the way values are calculated and validate PQ and event data.