Decomposition model for examination and optimization of reliability of the basic structure of UES of Russia

Abstract

The main provisions are outlined of the author’s model of electric energy systems and their associations (Unified Energy Systems of Russia, UPS), enabling to determine analytically the key parameters of reliability of operation of EES within generation facilities (generation adequacy) and trunk power grids (transmission reliability) subject to dislocation of generation facilities and electric loads, electric modes and reliability of operation of trunk power grids.For calculations of electric modes of operation of 750–220 kV power grids, Stott’s decomposition method is used involving simplification of the Jacobian matrix, the latter being divided into two independent subsystemsP → δ and Q → U, based on a weak functional link between P and Uand between Q and δ. When developing the model, much attention has been paid to improving the correctness in assessing the static and dynamic stability of the UES and taking into account these factors in the process of calculating the reliability of trunk power grids networks for each of the considered emergency situations. Special attention has been paid to improving the accuracy of estimates of economic losses (damage to the national economy) under various conditions of operation and recovery of UES: when working at low frequency, on actuation of automatic frequency load shedding (AFLS) devices and special load shedding automatics (SLSA), in case of sudden shutdowns, shutdowns with prior notice, and planned power supply restrictions. When forming the composition of consumers subject to restrictions, instead of the currently used proportional approach, the method of indefinite Laplace multipliers is used to reduce damage, based on taking into account the technological and economic response of various types of consumers to restrictions of their electrical loads. The calculations are concluded with an assessment of the annual average undersupply of electric energy and economic damage to consumers from disruptions of their power supply for the UES of Russia in 2017–2019, as a basis for optimizing the system reliability. It is shown that the probable annual average damage only in trunk grids of the UES of Russia amounts to as much as 1.2 percent of annual GDP, while its annual growth over the same period is estimated by the Ministry of Economic Development and the State Statistics Committee of the Russian Federation to be within 1.8%. Thus, due to the unreliability of the operation of only 750–220 kV main nets of UES, the national economy annually loses up to 2/3 of its annual growth.