The objective of this work is to develop algorithms to detect voltage variation events in power quality data and to figure out their characteristics. Voltage variation events covered in this work are missing voltage and motor starting events. The first part of this work describes the fundamental concept, characteristics and sources of voltage variation events. Next, this work describes the algorithms to detect voltage variation events. The verification of the algorithms is performed using simulated data from PSCAD/EMTDC and actual field data. The results show that the performance of the algorithms and the characteristics of voltage variation events are satisfactory. This work contributes to the development of detecting voltage variation events from a real distribution system and the analysis of voltage variation events.