Electric Power System (EPS) is continuously subjected to internal and external disturbances that cause changes in the operational parameters – the EPS response. Change in parameters depends on the type and magnitude of the disturbance, its application point (external factors), and the diagram and parameters of EPS elements (internal factors). The purpose of this paper is to provide methods for detection of network parameters that are most sensitive to external impacts, determine their relationship with EPS parameters, to use this information for improvement of EPS behavioural properties. The so-called weak points – nodes, links, sections, which are most "guilty" in the presence of sensors and the change in parameters of which is the most effective for removing excess sensitivity, are sought for this purpose. By doing so, the method that do not require statistical tests, busting of a huge number of options for scenarios. Singular Jacobian matrix and nodal conduction analyses are considered as these methods.