Determination of Energy Intensity of Autonomous Power Supplies Taking into Account Interruptible Service of Power Mains

A methodological approach for determining the energy intensity of autonomous power supplies in the presence of interruptible power service due to the overrange of supply quality indices has been considered. The modes of operation of the power supply system have been represented in the form of a Markov chain with discrete states and continuous time. The exponential rule of a working time distribution of the power feeds has been adopted. A marked graph of states of the power supply system that consists of the state electric mains, uninterruptible power supply equipment, and a standby diesel power station has been constructed. The matrix of transition probabilities has been created, and the analytical expressions have been obtained to determine ultimate probabilities. Since the ultimate probabilities are the mean relative residence time of the system in the given state, the analytical expression has been deducted to determine operating time of the storage battery used in the equipment of uninterruptible power supply. The operating time of other standby power supplies can be similarly calculated.