Using real or estimated power measurements to detect one or more anomalies in an AC electric network. In some implementations, one or more actions can be automatically performed in response to detection of the anomaly. Such action(s) can include causing automatic control of electrical resource(s) of the AC electric network to mitigate the detected anomaly/anomalies. For example, such action(s) can include automatically isolating the AC electric network in response to detecting the AC electric network has one or more anomalies, and optionally restoring the AC electric network after the abnormal conditions are no longer detected. For instance, this can include a main AC electric network isolating an AC electric subnetwork in response to detecting abnormal conditions in the AC electric sub-network or an AC electric sub-network isolating and islanding itself from the main AC electric network in response to detecting abnormal conditions in the main AC electric network.