Abstract:
The growing penetration of large blocks of renewable energy based on electronic inverters in
power transmission systems can decrease the power quality of these systems, especially with
increasing harmonic and interharmonic distortion and voltage fluctuation. Poor electrical
power quality (PQ) can negatively affect the protection system and can cause premature aging
of electrical equipment connected to the power system. Thus, continuous monitoring of the PQ
and in real time can be of great value for the operation, maintenance and expansion of the
power systems. This dissertation presents the real-time PQ monitoring system recently
implemented in two transmission substations of the company TBE (Transmissoras Brasileiras
de Energia) as part of the Aneel R&D project “Development of a monitoring system for power
quality and decision-making in transmission lines” and which involved the participation of
several researchers from UFJF, UNIFEI and UFSC. The monitoring system is based on the
philosophy of Digitally Enabled Substation Architecture or Substation 4.0 (SB4.0). SB4.0
involves concepts of open architecture, vendor independence, interoperability, and scalability.
The system developed for monitoring the PQ receives samples of voltage and current signals
from a Merging Unit (MU) through the IEC 61850-9-2 (SV) protocol and calculates the various
power quality parameters. As the system uses the SB4.0 concept, power quality monitoring is a
software application implemented on an industrial computer. In addition, the system provides
a Data Recording application, which runs as an additional software task that provides
instantaneous Total Harmonic Distortion (iTHD) triggered oscillography. This dissertation
presents the main aspects of the architecture of the system developed and implemented, as well
as the field results obtained from the two monitored substations.
