Voltage sag mitigation using overcurrent protection devices

The relationship between distribution system protection schemes and overcurrents, and thus voltage sags, is presented. Sources of interruptions and voltage sags are also reported. The Computer Business Equipment Manufacturing Association (CBEMA) curve is described and adopted as most representative of sensitive equipment capability to withstand voltage sags. A short introduction of the protection parameters, like types of faults, protection device characteristics, and fault prevention, is presented. The sit main sag mitigation measures are analyzed, studying their main, advantages and drawbacks, with some given examples. The main, emphasis is given to the recloser fast tripping elimination, dead time reduction, and the improving of the protection operating speed. Changes in protection criteria and circuit layout can avoid some sensitive equipment dropouts.