Probabilistic evaluation of critical clearing times for the analysis of transient stability

• Grant number: 17/15562-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2017
• End date: September 30, 2018
• Field of knowledge: Engineering - Electrical Engineering - Power Systems
• Principal Investigator: Rodrigo Andrade Ramos
• Grantee: Daniela Arantes Gomes Ferreira
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil

Abstract

The stability analysis of the Electric Power Systems is an area of study of great importance and has gained notoriety with the interconnection of the electrical systems. This analysis ensures a safe system operation, since the occurrence of instability can lead to the malfunction of electrical machines and equipments connected to the network. Another negative effect that may be a consequence of the electrical system instability is blackouts, that is the interruption of the electricity supply to the consumer. The short circuits are the main causes of disturbances in the Electric Power System (SEP), since it is difficult to predict them and to avoid them because they occur in a random way due to external agents. As the differential equations describing the systems are non-linear, in the case of large disturbances, in the study of transient stability, the stability evaluation must be done through numerical simulations. Fault parameters, such as their location and their impedance, influence system modeling during the transient and are also not predetermined. In this context, this research proposal has as main intention to seek improvements in SEP protection adjustments based on a probabilistic treatment of the parameters associated to faults. By performing a careful analysis of the distribution of the critical clearing times generated by numerical simulations, taking as input a well-defined probabilistic distribution for the points where the fault can occur, it is possible to define a maximum time to which the protection must act in order to isolate the fault and keep the remaining system on stable operation, preventing the disturbance from affecting a larger part of the network. In this way, it is possible to increase the transient stability margin of a system and adjust it to reconcile it with the other protection requirements. (AU)