To determine the payments for delivered electricity and the power losses arising from the supply of electricity, the amount of electricity delivered from a power station to a certain consumer (reciprocal power) should be known. This to be done, it is not necessary to trace the flow of electricity. The superposition principle can be applied. The network is represented by generator nodes and consumer nodes connected by transmission line or by network branches. Generator nodes are fed by generator currents, consumer admittances determined at normal power flow mode are connected to consumer nodes. This circuit is energized by all generators in turn sending to their nodes currents equal to those in normal operation mode. Reciprocal current of a specific consumer node and a given generator is determined out of voltage across this consumer and its admittance. Reciprocal power loss then is determined by method of reciprocal current increments.