In order to increase the accuracy of power flow (PF) calculations, the design scheme should account for load static characteristics (SC). The problem arises when calculations consider a «complex» load node featuring several dissimilar interconnected electrical receivers controlled by a single measurement unit. The process of searching for an appropriate SC of the complex load node is usually referred to as the SC identification. A large number of papers [1-6] are devoted to this problem. In general, there are two approaches how to collect the necessary information [7]: numerical simulation and field tests. The numerical simulation requires collecting the following data for the complex load node: types of electrical receivers and their SC; electrical power system (EPS) topology; load schedules; applied automated control devices aimed at regulating of PF parameters and their settings. When a relatively large fragment of the power system is considered, it becomes quite difficult and time-consuming to collect all the necessary information. Field tests involve measurements of PF parameters and its processing with the use of statistical data analysis methods. Field tests can be divided into two groups: a passive experiment and an active experiment. In the first case, the current parameters of the PF are recorded without the researcher intervention in the operating mode of the EPS. The key advantage of this approach is the absence of negative impact on the system reliability and, as a result, faster approval of the experiment program by electricity market subjects (system operators, generators, grid companies, utilities, key consumers). The main drawback of the passive experiment is the fact that statistically significant estimates of the SC coefficients in this approach require a relatively long-term observation time (for example, several months). Moreover, SC for certain load configurations cannot be identified even after a very long observation. In contrast to the passive experiment, the active approach implies a forced change in PF parameters in the analyzed node of the power grid. The main advantage of the method is the possibility of obtaining statistically significant estimates of SC coefficients for a wide range of nodal voltages. The paper considers the problem of identification of voltage static characteristics for a complex load node, basing on the data of field tests (an active experiment) taking into account the factor of a characteristic daily load changes.