A risk-based approach for short term security assessment with voltage stability constraint is presented in this paper. This approach includes voltage-stability considerations in reactive power adequacy assessment of a composite power system. The proposed method is based on probabilistic criteria because deterministic risk criteria do not define consistently the true risk in the system. For risk calculation, in this paper, load and parametric uncertainties and system contingencies are considered. Then the effects of uncertainties and contingencies on bus voltage violation are calculated. The required reactive power is determined based on the calculated voltage violation in order to maintain the bus voltage in an acceptable range. At the end, to make a trade-off between reliability and economics, the local reactive power adequacy is calculated using the reliability cost/worth concept. The effect of voltage violations on reliability indices and required reactive power is illustrated in a reliability test system (6-bus RBTS).
Rahimi, M., Fotuhi-Firuzabad, M., & Karimi, A. (2016). Short term voltage-based risk assessment by incorporating reactive power adequacy. Ain Shams Engineering Journal, 7(1), 131–141. https://doi.org/10.1016/j.asej.2015.11.015