BASIC EQUATIONS OF THE MULTI-CIRCUIT, MULTI-PHASE AC POWER LINES

Abstract

Different types of overhead lines (AC) of AC transmission are described and classified according to the main distinctive features.. All types of AC overhead lines in the design schemes are modeled by parameters that take into account their specificity. For all types of AC overhead lines, the calculated values are the specific values of the longitudinal active (r0) and inductive (Х0) resistances, as well as the transverse specific conductivities: active (g0) and capacitive (в0). Additional characteristics are: characteristic impedance (Zc), natural power (PH) and charging power (Qc). Inductive resistance and transverse capacitive conductivity depend on the strength of the magnetic and electric fields, respectively, which, in turn, depend on the design of overhead lines and parameters and mode - voltage phases and flowing currents. Characteristics of overhead lines in general are determined by the specified parameters and the length of the line. All interconnections of parameters and operating characteristics of an overhead transmission line are described by their basic equations. The article presents the basic equations for the most general case of the basic equations of voltage and current of an overhead transmission line containing any number of phases, forming the corresponding number of circuits for stationary full-phase and half-phase modes. Initially, equivalent circuits of multi-phase multi-phase overhead lines were developed, then equations of voltage and current distribution over an infinitesimal portion of overhead lines in partial derivatives were compiled. After the transition to sinusoidal images of current and voltage, the equations are integrated. Thus decisions ina general view turn out. Then the initial conditions are formed - the integration constants, the calculations of the distribution of voltage and current along the line are performed. Calculations are made for the example of a double-circuit compact USVL-500 kV. The data are presented in tabular and graphical form