Abstract Voltage security problems, an indispensable aspect of power system studies, highly depend on the system limits and the limits can greatly restrict the loading capability of networks. The techniques proposed in this paper are able to evaluate voltage stability status efficiently in both pre-contingency and post-contingency states with considering the effect of active and reactive power limits. The proposed method also employs the adaptive continuation technique and local analysis of the contingency effect. Moreover, to enhance voltage security, it is essential for system planners and operators to recognize vulnerable areas of the power system. Thus, the method is also developed toward determining vulnerable buses of the power system with respect to voltage security. It is shown that power limits have a major effect on vulnerability of buses. The proposed techniques have been examined on two practical systems, power networks of New Zealand and Iran. Obtained results, discussed comprehensively, indicate the efficiency of proposed approaches.