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The paper presents a novel adaptive stator ground fault protection scheme with fault location capability for high-impedance grounded synchronous generators. The protection scheme uses already available neutral grounding signals in the existing subharmonic injection protection to obtain a Kalman adaptive filter (KAF) for real-time stator insulation parameter estimation. The KAF estimator yields a method of continuous tracking of stator insulation condition during healthy operations. This information is then used for real-time stator ground fault detection as well as fault location. The effectiveness of the proposed method is verified using extensive experiments performed on a lab-scale unit-connected generating station. [ABSTRACT FROM AUTHOR]

The paper presents a new adaptive 100% stator ground protection for high-impedance-grounded (HIG) synchronous generators. This is done by first examining reliability, that is, dependability and security of the most prominent conventional 3rd-harmonic voltage schemes. Using field data from various capacity industrial generators, it is shown that the conventional 3rd-harmonic differential voltage scheme, while being dependable, lacks security. Using the same field data, it is shown that the new adaptive scheme is a highly secure and sensitive scheme. Moreover, the new adaptive scheme is a zero-setting scheme which does not require any setting calculations, 3rd-harmonic voltage testings, or additional hardware. [ABSTRACT FROM PUBLISHER]