Global power quality indices for assessment of multipoint Power quality measurements

This paper presents an extended definitions of global power quality indices (GPQIs) applied for analysis of multipoint power quality measurements. A definitions of two GPQIs has been performed introducing aggregated data index (ADI) and flagged data index (FDI). The ADI is based on selected classical PQ parameters like frequency, RMS level, flicker severity, unbalance, harmonics. The aggregation time of particular PQ parameters is typical 10 minutes and the flagged data are extracted. Additionally definition of ADI is extended including parameters of envelope of voltage deviation created by maximum and minimum of 200 ms rms values within 10 minutes. As the support for ADI the FDI definition use extracted number 10 minutes flagged date which are rejected from classical power quality assessment due to abnormal state of the system work. Introduced definitions of ADI and FDI has been tested on the basis of real multipoint power quality measurements performed in mining industry power system. Using definition of proposed GPQIs allowed to assess impact of distributed generation (DG) on local working condition of electrical power network.