New loss of mains detection algorithm for embedded generation using rate of change of voltage and changes in power factors

The work reported in this paper proposes a new method for detecting loss of mains (LOM), which considered one of the basic protection systems that should be provided for an embedded generator (EG). The proposed LOM protection particularly considers the case when the EG is “islanded” with part of the utility load which has a capacity close to that of the generator. It also has the capability to deal with the difficult situation related to differentiate between LOM and the loss of parallel feeder at the interfacing circuit between EG and the utility. The proposed method is based on using the rate of change of voltage (dV/dt) and the change in power factor (Δpf) measured at the interfacing point between the EG and the utility network