Optimal PMU placement method for complete topological observability of power system under various contingencies

•The effect of channel capacity of PMUs on their optimal placement is investigated.•A method for optimal placement of PMUs with limited number of channels is proposed.•The method is extended for assuring full observability under various contingencies.•The scalability of the method is demonstrated on several IEEE test systems.•The results show that the proposed method can be applied to real-world network. In optimal phasor measurement units (PMUs) placement problem, it is assumed that each PMU can measure unlimited number of voltages and currents. However, available PMUs have limited number of channels and cannot measure the current phasors of all their incident lines. This paper investigates the effect of channel capacity of PMUs on their optimal placement for complete power system observability. At first, the conventional complete observability of power networks is formulated. Then, a revised formulation for the optimal placement problem of these types of PMUs is presented. Proposed method is further extended for assuring complete observability under single PMU loss or single line outage cases. The proposed method is demonstrated on several IEEE standard test systems and compared with the existing techniques. Results show that the proposed method is simple to implement and accurate compared to other existing methods.