MODELING THE MODE OF A LONG LINE WITH NONLINEAR CONDUCTIVITY BY EQUATIONS IN HYPERBOLIC FUNCTIONS

The most accurate and standard modeling of steady-state modes of an overhead line using long line equations (LLE) with distributed parameters in hyperbolic functions is accepted. When obtaining the LLE, an assumption was made about the quadratic dependence of active power losses to the corona on voltage. Numerous measurements of active power losses to corona in overhead lines of ultra-high voltage (UHV) and processing of experimental results have established that the dependences of active power losses to corona are a function of voltage of the 4–8th degree. It is difficult to obtain analytical equations of a line with distributed parameters in hyperbolic ones, taking into account the function of stress by dependencies that differ from the second degree by mathematical transformations. This article proposes a methodology, algorithm and software implementation for modeling active power losses to the corona as a voltage function with a real dependence with an arbitrary degree, taking into account the voltage distribution along the line. Comparison of the corona loss values obtained by direct integration of the voltage along the overhead line of the ρ-th degree according to LLE taking into account the equivalent conductivity inserting into the LLE is performed. An algorithm and program are proposed in the form of a computational software module based on LLE modeling, considering active power losses to the corona due to nonlinear conduction. To modeling overhead lines with nonlinear conductivity to the corona according to LLE, it is proposed to use the reduced value of the equivalent conductivity to the crown of the overhead line. Calculations of steady-state modes of UHV transmission lines have been carried out and the errors of simplified models have been compared. The module to calculation of the EHV overhead line modes can be applied: to designing the EHV overhead line; to analyze of the modes for optimal operation of OHL; to compare of the accuracy of steady-state models of EHV OHL. Keywords: overhead power line, ultra-high voltage, distributed parameter line equations, corona losses, nonlinear conductivity.