Specific Indicators of the Consequences of Outages in 110 kV Electrical Networks

Introduction. Comparing the effects of outages in electrical networks of different voltage classes is important for developing strategies for their design and construction. The main scientific problem when choosing such strategies arises from the contradiction between the need to increase the reliability of equipment and structures of electrical networks of all voltage classes and to minimize capital investments and operating costs. A comparison based on specific indicators is more visual and makes it possible to scale the results obtained. Thus, it is an urgent task to assess the specific indicators of the consequences of outages in 110 kV electrical networks for their subsequent comparison with similar indicators for networks of other voltage classes. Aim of the Study. The study is aimed at conducting a comparative analysis of specific reliability indexes characterizing the consequences of outages in 110 kV and 0.4 kV electrical networks. Materials and Methods. There were analyzed the statistical data of emergency and planned outages in 110 kV electrical networks in the Oryol region for the period from 2018 to 2023. The initial data were taken from the outage log books for the branch of PJSC Rosseti Centre – Oryolenergo. The total length of the electrical networks considered was more than 1.7 thousand kilometers. Specific reliability indexes characterizing the consequences of outages in 110 kV electrical networks were determined and compared with similar indexes for 0.4 kV electrical networks. Results. The study revealed that the consequences of emergency outages in the 110 kV electrical networks in terms of specific disconnected electrical power indicator per one outage in 110 kV electrical networks are on average about 50 times greater than the consequences of outages in the 0.4 kV electrical networks and taking into account all causes of outages – 17.5 times. The average specific time of emergency interruptions per one outage in 0.4 kV electrical networks is more than 5 times greater than in 110 kV electrical networks. Specific undersupply of electrical power per one consumer in 0.4 kV electrical networks is greater than in 110 kV electrical networks by more than 2,160 times taking into account all causes of disconnections while specific electrical power undersupply per outage disconnection in 0.4 kV electrical networks is 18 times greater. The average total undersupply of electrical power for all reasons in 0.4 kV electrical networks is more than 7,500 times greater than the same indicator for 110 kV electrical networks. Discussion and Conclusion. The total annual consequences of accidents in 0.4 kV electrical networks are greater than the consequences of accidents in 110 kV electrical networks. It is necessary to revise the design standards for 0.4 kV electrical networks increasing the requirements for the reliability of their design and creating opportunities for configuration management, primarily for the purpose of automatic standby electrical power supply to consumers. This will significantly reduce damage to both rural consumers and power grid operators.