Algorithm for determining phase-angle observability in the presence of line-current-magnitude measurements

The paper presents an algorithm for the phase-angle observability of networks containing real power as well as line current magnitude measurements. It is assumed that all bus voltages are measured or known and the observability problem is solved only for the phase angles. The existence of line-current measurements creates the possibility of multiple solutions. Available methods of testing network observability cannot identify such multiple solutions. The algorithm described ensures that a unique solution for the phase angles exists for the given set of measurements. The algorithm is described in detail by using numerical examples