Application of parity mismatches in detection of bad data for power systemstate estimation

Measurement residuals have been conventionally used in the detection and id entification of gross errors in poser system state estimation. Other types of mismatches have been employed in failure detection of complex plants, th ough their application to power systems have not yet been reported. Paramet ers in power systems can be used for the purpose of generating such mismatc hes called parity mismatches in this paper. Parameters calculated from meas urements containing erroneous ones differ from their true values resulting in parity mismatches. In this paper, parity mismatches are employed for ide ntification of gross errors in given measurements. A relation between parit y mismatches and measurement residuals has been derived. Similar to the met hod of residuals, normalisation can be effected on parity mismatches. Physi cal appeal of the parity mismatches enables one to adopt normalisation whic h improves the detectability of bad data in short lines. A segregated treat ment for real, reactive power floss and also the injections can be applied unlike the method of residuals.