QV Analysis for the Identification of Vulnerable Zones to Voltage Collapse: A Study Case

Abstract

Radial High-Voltage networks have problems ensuring voltage stability when a fault occurs. Among preventive actions for these events, installing reactive power compensation in the most vulnerable zones to voltage instability is an economical and simple alternative. Previous works have used the QV curves methodology based on contingency power flows to identify such zones. However, this method has been criticized because it does not consider the dynamical effect of some network elements that depend on the voltage levels, especially in contingency scenarios. This article proposes a QV curve analysis based on the operating point resulting from dynamic simulations to amend this critique. To evaluate the proposed procedure, the model of the Patagonian High-Voltage Network in southern Argentina is used through the PSS/E software with the help of the Python programming language. The results detect the most vulnerable areas to voltage instability after a fault occurs and the reactive power necessary to maintain voltage levels in an acceptable operating range. The proposed methodology can be applied to other networks. For example, it can be used in the Latin-American context to assess future network expansions, especially on those linking countries, such as Ecuador with Perú or Colombia, or even the Centro American Interconnected System.