Probabilistic PMU placement considering topological change in high voltage substations

• In regular PMU placement methods, all substations are considered as simple buses.
• Substations in real networks have complex busbars such as double busbar.
• Basic formulation for PMU placement is modified according to bus types.
• Connection probability is considered for identifying unusual configurations.
• The best placement can be selected with network observability and cost awareness.

WAMS and WAMPAC are developed recently in the world electrical networks. PMU forms the basis of WAMS networks by measuring the main electrical parameters (bus voltage and feeder current). It is not necessary to use PMU on all of the network buses for a full observability and many studies are done for optimizing PMU numbers and placement in electrical networks. Considering simple buses for the networks is a common assumption in these studies. While practically, the busbar arrangement is not simple in high voltage substations, especially in 230 and 400 kV substations. As a result, it is feasible under different utilization condition that the substations be sectionalized and turns into two separate buses. In this paper a modified PMU placement method is presented considering different busbar arrangement in substations and possibility of network topology variation due to feeders’ connection exchange at substation breakers opening/closing. In the revised method, at first step an optimized placement is aimed for full observability of each network under all configurations and at the second step, an improved placement is the goal in which the network small value of unobservability is acceptable under certain degree of risk. The test results on IEEE standard networks are presented.