Improved computations of the voltage collapse point using the P-index

Online voltage stability assessment of power system is important to ensure reliability and security. Over the years, many voltage monitoring indices have been documented in the literature. These indices are designed to quantify proximity to voltage collapse. However, they all have inaccuracies when predicting the voltage collapse point. A recent research project resulted in a new robust voltage stability monitoring tool called the P-index. A method that utilizes linear approximation of Voltage-Load relationship was introduced alongside the P-index, providing enhanced precision compared to most recognized indices. However, this method generates a high level of inaccuracy because the actual Voltage-Load behavior in general is non-linear, but rather more complex. This study proposed two new models that take into account the nonlinearity of Voltage-Load relationship, providing an enhanced representation of its complexity. Moreover, these models have a higher accuracy in predicting voltage collapse points than the linear method