Newly Implemented Real-Time PQ Monitoring for Transmission 4.0 Substations

Abstract

The growth of penetration of large blocks of inverter based renewable energy in transmission power systems may lower the power quality of these systems, especially with rising of harmonic and interharmonic distortion and voltage fluctuation. Poor Power Quality (PQ) can negatively affect the protection system and may cause premature aging of electrical equipment connected to the power system. Thus, real-time and continuous PQ monitoring can be of great value for operation, maintenance and expansion of the system. This paper presents a recently implemented real-time PQ monitoring system based on the concept of Digitally Enabled Substation Architecture or Substation 4.0 (SB4.0). The proposed PQ monitoring system receives voltage and current signal samples from a Merging Unit (MU) and calculates the various power quality parameters. Since the system uses the SB4.0 concept the power quality monitoring is a software application implemented in an industrial computer. Also, the system provides a Data Recording application, running as additional software task that provide oscillography triggered by instantaneous Total Harmonic Distortion (iTHD). This paper presents the architecture of the developed and implemented system as well as the field results gathered from a transmission system in the north of Brazil.