Expanding the Field of Synchronized Phasor Measurements Application in Power Systems

Abstract

Expansion of synchronized measurement application due to the use of equivalent synchrophasors and higher harmonic synchrophasors is considered. The use of equivalent synchrophasors will significantly increase the number of power system mode calculated parameters. The application of equivalent synchrophasors will increase the controllability and reliability of the power system. Before calculating the equivalent current and voltage synchrophasors in IEDs, it is necessary to first determine the current and voltage values, active and reactive power. Various algorithms of reactive power measurements are considered. The disadvantages of using the Hilbert transform to calculate reactive power in the presence of higher harmonics are indicated. More efficient algorithms for measuring reactive and apparent power are proposed. Algorithms for the equivalent synchrophasors formation have been developed, which make it possible to calculate reactive power in various ways: as the sum of reactive harmonic powers, based on the apparent and active power, by the fundamental harmonic, etc. Using equivalent synchrophasors will allow calculating symmetric components of currents, voltages, powers taking into account higher harmonics. Higher harmonic synchrophasors can be used to restore the secondary current of the measuring transformer due to its nonlinear distortions caused by the core saturation. Secondary current restoration is performed based on the previously obtained relationship between the saturation degree of the current measuring transformer and higher harmonic synchrophasor values. The simulation results of secondary current restoration using the virtual Simulink model are given. The simulation results confirmed the effectiveness of the proposed algorithm and its potential for use in differential protection devices of transformers, motors, power lines, etc. The proposed approach can be used in other technology fields for the restoration of sinusoidal and modulated signals at nonlinear distortions.