Calculating the sequence of stationary modes in power distribution networks of Russia for wide-scale integration of renewable energy based installations

Abstract

The global trend of the past decades on the development of the decentralized power generation concept is associated with the growing number of power plants integrated into power distribution networks including those employing renewable energy sources. In recent years, high-capacity wind power and solar PV stations have been put into operation, in Russia, and wide-scale construction of micro-generation sites is at the stage of planning and design. Under these conditions, power distribution networks will be permanently affected by the deviation of operational status that can be indicated in the temporary change of stationary mode parameters. Currently it is not technically possible to equip all network control and supervision Centers with hardware and software complexes designed to calculate automatically transients in operation modes in order to work out decisions on prompt actions for controlling network operational status and maintaining its operation modes within the range of permissible values of their rated parameters. In this article, the principles have been analyzed that enable to apply the existing software complexes for calculating the sequences of stationary operating modes (SSOP). Results of calculating SSOP make it possible to perform the analysis of changes that may occur in power distribution, in transient conditions, and to work up reasonable control actions in order to stabilize operation modes of power network equipment. Properly estimated amount of available reactive capacity of generating installations helps to prevent critical voltage drop in load nods, as well as occurrence of voltage avalanche, in installations, particularly in industrial power consuming areas. In power distribution networks, operating mode characteristics essentially depend on parameters of loads due to their comparability with the aggregate capacity of generating installations and low interaction impedance. The issues of accurate load modeling and those of possible assumptions have been considered. The principles of application of the results of SSOP calculations for the analysis of the effect of voltage control devices, in live conditions, automatic voltage control equipment and quick-response shunt compensation devices that make their contribution in VAR flow and distribution power network operation have been demonstrated.