Effect of Frequency Offset on Power Measurement Error in Digital Input Electricity Meters

摘要

The realization principle of digital input electricity meters and the present situation of the conventional power algorithm in the field of signal processing are introduced. According to the onsite operating conditions, formulas are derived for changes in active power and reactive power with frequency offset or phase change, aiming at the influence of nonsynchronization sampling created by the frequency offset. The corresponding analysis was simulated. The theory and simulated analysis indicate that the influence caused by frequency offset could cause excessive errors in digital input electricity meters at substation sites. A weighted algorithm is proposed to effectively reduce the influence to a negligible level. Error measurements of the frequency offset in the laboratory verify the analysis results. Finally, rationalization proposals are given for the software algorithm in digital input electricity meters.