External Power Supply Reliability Assessment to Consumers of 6-10 kV of the Substations of 35 kV and Higher

Assessing the reliability of external power supply is an important step in choosing a circuit for a high-voltage switchgear at main step-down substations. The main task in calculating the reliability indicators is to estimate the recovery duration and the failure flow parameter in order to determine the likely economic damage, which also depends on the size and type of load. This paper proposes a unification of calculations for assessing the reliability of external power supply circuits of the main step-down substations with a voltage of 35 kV and higher, which makes it possible to speed up the process of choosing the optimal switchgear circuit and evaluate the damage from a power outage. The developed algorithm makes it possible to determine, based on the technical specifications for designing, the value of the failure flow parameter and recovery time for switchgear circuits, converting them into a structural-analytical circuit that reflects the logic of the circuit in heavy duty mode (including redundancy of individual circuits, bypass, bus junction and section switches) In the calculation, an analytical method was used, based on the equivalentization of the structural scheme using the forced downtime coefficients. The work is carried out with the financial support of a grant from the President of the Russian Federation for young scientists - candidates of sciences MK-939.2019.8.