Conductivity power of zero sequence for asymmetrical non-sinusoidal modes of three-phase electrical network with grounded neutral wire

Abstract

The paper analyzes the work of a three-phase network with grounded neutral wire with nonlinear asymmetric consumers based on the theory of instantaneous power. In non-symmetric, non-sinusoidal modes of three-phase electric networks with grounded neutral wire, instantaneous reactive power contains three components. The regime’s imbalance is characterized by instantaneous active and reactive conditional capacities of zero sequence qb and qa. Conditional powers of the zero sequence qb and qa contain components that are due to asymmetry and non-sinusoidal mode character, which are characterized by a constant qb and qa an alternating component respectively. Since the positive, negative and zero sequence of voltage and current in the asymmetric non-sinusoidal mode are defined as the sum of the symmetric components, respectively, of the positive sequence of the first and seventh harmonics, the negative sequence of the first and fifth harmonics, the zero sequence of the first and third harmonics, the presence of the first harmonic of current and the voltage of the zero sequence forms the constant component and the second harmonic of capacities qb and qa, and the presence of the third harmonic of current and voltage forms mainly the second and fourth harmonics of these capacities. It is expedient to divide instantaneous conditional power qb and qa into instantaneous conditional capacities , which are determined by the product of instantaneous positive and negative sequential stresses on the zero sequence current, and the instantaneous conditional capacities that are determined by the product of instantaneous currents of the positive and negative sequences on the voltage of the zero sequence. The analytical expressions for the determination of the permanent components in the integral and complex forms of recording for the conditional capacities that characterize the imbalance of the current regime and the zero sequence voltage that can be used in the process of symmetry and compensation of higher harmonics have been obtained