On-line tracking of single phase reactive power in non-sinusoidal conditions using S-ADALINE networks

This paper presents design and implementation of a new on-line single phase reactive power measurement technique under non-sinusoidal conditions. The proposed method expresses the conventional reactive power definition in a suitable state space form to avoid use of quadrature phase shifting method in measurement, thus, improving estimation accuracy. A modified adaptive linear combiner (ADALINE) structure has been introduced which is capable of dealing with off-nominal frequency conditions rather than the existing ADALINE, which provides good accuracy only at nominal frequency. The new topology is able to synchronize itself with the system signals using an efficient fundamental angular frequency deviation estimation algorithm and is called S-ADALINE. The principle and the architecture of this S-ADALINE is well suited for on-line implementation of the proposed reactive power measurement algorithm. Illustrative laboratory test results confirm the validity and accurate performance of the proposed method under both static and dynamic conditions.