Phase selection for traveling wave fault detection systems is disclosed herein. Intelligent electronic devices (IEDs) may be used to monitor and protect electric power delivery systems by detecting and acting upon traveling waves. A phase of the electric power delivery system may be selected based on the relative polarity of the traveling waves detected. The amplitude and/or polarity of the selected phase may be compared with the amplitudes and/or polarities of the other phases to determine a fault condition. For instance, the IED may determine a single-phase-to-ground fault based on the relative polarities and magnitudes of the detected traveling waves, send a protective action to the identified faulted phase, and/or continue to monitor the system for a continuation of the event or identification of a different event, such as a three-phase fault, using incremental quantities.

A state estimation method for a multi-stage voltage sag comprises analyzing characteristics of multi-stage voltage sags due to different causes. A method for determining the cause of sudden change time of an amplitude of the multi-stage voltage sag is based on a jump characteristic of the sag amplitude. Calculation methods of a relay protection action matrix and a faulty line set are utilized to preliminarily obtain a faulty line set based on the fault clearing time of a relay protection device and other characteristics to effectively reduce a calculation amount of sag state estimation. Based on a substantive characteristic that different events cause a change of system impedance, a method for inferring a cause of an event in each stage of the multi-stage voltage sag is used to improve the accuracy of the state estimation. The state estimation method reduces the difficulty in applying to the multi-stage voltage sag.

Embodiments of the present disclosure may enable an electrical component within an electrical distribution equipment cabinet to be audibly monitored via an electrical fault detection device mounted on the housing of the cabinet. The electrical fault detection device may comprise a senor to detect a signal emitted from an electrical fault within the cabinet, a transducer to convert the detected signal into an electrical audio signal, and an output socket adapted for an external device that may generate an audible sound based on the detected signal. The detected sensor may be an ultrasound sensor and the detected signal may be an ultrasound emitted from the electrical fault.

A node for detecting local anomalies in an overhead power grid having at least one power line. The node includes a processing unit and a memory, wherein the node further includes: an electric field sensor configured to measure a first parameter related to an electric field around the at least one power line, and a magnetic field sensor configured to measure at least second parameter related to a magnetic field around the at least one power line. The processing unit is configured to: compare the measured first parameter and at least second parameter with historic data stored in the memory to identify local anomalies, and forward data related to the identified local anomalies to a system controller via a communication interface.

An electric utility distribution system in which power is supplied by a distribution transformer through an electric utility meter including an apparatus for detecting the presence of a back-feed voltage source connected to the load. The apparatus includes a virtual neutral established in the electric utility meter at ground potential and a remote switch that is opened to interrupt electric power flow from the distribution transformer to the load. The apparatus further includes a balanced voltage divider circuit including a connection point established between a pair of series connected resistive elements. In addition, the apparatus includes a detection circuit configured to monitor a voltage signal at the connection point to detect a back-feed voltage source connected between a neutral conductor of the electric utility distribution system and one of a first or second power line at the load.

A method and authenticator for authenticating a device in a system using the electrical properties of the device is disclosed. Embodiments of the disclosure enable authentication by receiving a plurality of input seed values from a requestor. For each input seed value, load stimuli are generated to produce an electrical load sequence on a power delivery network powering at least part of the system. Noise induced in the power delivery network is measured in response to the electrical load sequence using one or more sensors located on the power delivery network. Based on the measured noise, a dynamic response property (magnitude and phase response as a function of frequency) of the power delivery network corresponding to a respective input seed value can be determined and returned to the requestor.

A method and apparatus for identifying a fault in an alternating current electrical grid is provided.

The disclosed method detects anomalies in an electrical network. An ohmic matrix model of the network is initially generated from consumption measurements produced by meters connected to a same transformer. The model has currents carried by the meters as input, relative voltage drops of the meters referenced to a voltage of a reference node located on the network as output, and resistive quantities initially determined by currents and voltages based on the consumption measurements as matrix terms, the relative voltage being a voltage difference between a voltage determined for a meter and an average of voltages determined for a set of meters of the network. The model is iteratively modified according to detected anomalies, and a diagnosis of the network characterizing the detected anomalies is provided.

A method for controlling a power distribution network includes receiving, via an electronic processor, a fault indication associated with a fault from a first isolation device of a plurality of isolation devices. The processor identifies a first subset of a plurality of phases associated with the fault indication and a second subset not associated with the fault indication. The processor sends a first open command to each member of a set of downstream isolation devices for each phase in the first subset. The processor identifies a plurality of tie-in isolation devices to be closed to restore power. Responsive to identifying a first potential loop configuration, for each of the plurality of tie-in devices, the processor sends a close command to the tie-in isolation device for each of the plurality of phases and sends a second open command to the associated downstream isolation device for each phase in the second subset.

Techniques for controlling a power distribution network are provided. An electronic processor receives, a fault indication associated with a fault from a first isolation device of a plurality of isolation devices. The processor identifies a first subset of a plurality of phases associated with the fault indication and a second subset of the plurality of phases not associated with the fault indication. The processor identifies a downstream isolation device downstream of the fault. The processor sends send a first open command to the downstream isolation device for each phase in the first subset. The processor sends a close command to a tie-in isolation device for each of the plurality of phases. The processor sends a second open command to the downstream isolation device for each phase in the second subset. Responsive to identifying a potential loop configuration, the processor sends the second open command prior to the close command.