A new power quality deviation index based on principal curves

•The principal curves technique is used to construct a new PQ deviation index.•The proposed PQ index is general, i.e., it can be used for any type of disturbance.•The PQ index measures how much the actual voltage is deviated from the ideal voltage.•The index can also be used for disturbance detection and classification purposes.•In the operational stage, the PQ index is achieved by simply computing a distance.

In this paper, a new power quality deviation index based on principal curves is proposed. The index provides a quantitative measure, which gives an idea of how much the monitored electrical signal has deviated from the nominal one. Differently of existing indices, the proposed index is a general index, i.e., it can be used for any type of disturbance in the monitored signal. In addition, the proposed index is used to perform a direct approach for detecting disturbances in power signals. This approach is able to detect the beginning and localize the disturbance by analyzing non-overlapping signal windows of one cycle of the fundamental component, leading to a simple method in terms of computational complexity.