Bad Data Identification When Using Phasor Measurements

Synchronized phasor measurements obtained by phasor measurement units (PMU) are rapidly populating power systems. Among the expected benefits of having these measurements are the potential improvements in the accuracy and reliability of state estimation. On the other hand, state estimation formulation will have to be modified when phasor measurements are incorporated due to two issues. One is related to the reference bus selection which is no longer needed when phasor measurements are present. The other is the numerical problems encountered during initialization if current phasor measurements exist. This paper presents a reference-free rectangular state estimation method to address both of these problems. Furthermore, it is also shown that bad data in any of the phasor measurements can be detected and identified provided certain redundancy re quirements are met. These requirements are illustrated using example systems and measurement configurations.