The article discusses the mathematical model fundamentals of the power distribution problem, that makes it possible to simulate the main power grid technological process activity - transmission and distribution of electrical energy (EE) flows. The energy distribution problem application is associated with EE balances, technical losses evaluation, commercial losses localization, unreliable EE metering devices identification as well as their metrological characteristics monitoring by calculations. State estimation and observability theory methodological approaches provide EE metering systems development optimization and additional metering units installation that allow observability and redundancy criteria numerically assessment. Based on the EE transmission process model, a subsystem for calculating and analyzing financial and economic indicators of power grid activity has been developed. The power-cost distribution model relates the technological parameters of the EE transmission process with its economic indicators. This model provides cost distribution of transmission services and their components between consumers individually, taking into account electrical equipment loads and power losses assessment. At the same time model is used to estimate the unit cost of EE transmission for all power grid nodes.