Evaluation and identification of critical zones due to sag activity

This paper proposes a methodology to identify critical zones in electric distribution systems due to sag activity. The methodology is based on the acquisition of Power Quality (PQ) information in substation buses, measurements that are obtained through a PQ analysis system demanded by the Colombian regulator CREG1 to all electric distribution companies of the country. The methodology is developed in three stages. The first stage consists in a preprocessing of sag events data and its proper organization in a PQ database. Next, the sag activity assessment in each substation bus is achieved as a function of both, the number of times that each substation bus was the cause of a sag event and the number of substation buses affected by that particular sag event. Finally, a geographical identification by means of sag maps where the electric companies may focus their efforts to improve PQ. This methodology was applied to the whole electric distribution system in Bogota-Colombia, showing some interesting results.