A method for isolating a fault in an underground power distribution network. The network includes a power line, a plurality of transformers electrically coupled to and positioned along the power line, a first recloser connected to one end of the power line and a second recloser connected to an opposite end of the power line, where each transformer includes an upstream switching device and a downstream switching device, and where power is provided to both ends of the power line through the first and second reclosers and one of the switching devices is a normally open switching device. The method includes detecting overcurrent by some of the switching devices, detecting loss of voltage by some of the switching devices and sending clear to close messages to some of the switching devices to open and close certain ones of the switching devices to isolate the fault.

A relay array may connect an electrical device (e.g., an inverter, power converter, etc.) to a utility grid. Based on a detection of a power interruption or fault, the relay array may disconnect the electrical device from the grid to ensure safety or reduce damage to the electrical device or grid. The relay array may include one or more electromechanical relays (e.g., latching relays). A safety catch may prevent the latching relay(s) from changing states. The electrical device may be configured to facilitate removal of the safety catch once the ability to change states is desired. The latching relay(s) may also be supplied with a power pulse for changing a state of the latching relay(s). The power pulse may be provided by a power bank that may be maintained with power in case of a power interruption or fault.

A communication-based permissive protection method for protecting an electrical power distribution network from a fault. The network includes a power source, an electrical line and a plurality of fault interrupters, where the fault interrupters are operable to prevent current flow in response to the fault. The method includes detecting the fault by each fault interrupter that is between the fault and the power source, and sending a drop of voltage message from each fault interrupter that doesn't detect the fault, but does detect a drop of voltage as a result of the fault to its immediate upstream fault interrupter. The method opens the fault interrupter that both detects the fault and receives a drop of voltage message from all of the fault interrupters immediately downstream of that fault interrupter.

A detection scheme for temporary overvoltages and/or ground fault overvoltages in electric power systems is described. Current passing through a surge arrestor component of the power system is monitored. An algorithm for identifying one or more frequency components of the measured current signal is performed to screen out unwanted harmonics. In some embodiments, this is a frequency domain analysis. The frequency component(s) of the current signal is then compared to a calculated pickup current or pickup voltage of the system to determine if system protection steps should be undertaken.

Communication enabled circuit breakers and circuit breaker panels are described. Methods associated with such communication enabled circuit breakers and circuit breaker panels are also described. A circuit breaker panel may include a circuit breaker controller and one or more communication enabled circuit breakers. Two-way wireless communication is possible between the circuit breaker controller and the one or more communication enabled circuit breakers.

An electrical system for a motor vehicle includes a current distributor; a plurality of first lines which are designed to connect a corresponding plurality of electric components to the current distributor; a plurality of semiconductor-based first switch elements, wherein a specified first switch element of a specified first line is designed to interrupt said specified first line; a second line which is designed to connect the current distributor to the electrical system; a limiting unit which is designed to limit or prevent a second current on the second line; and a control unit which is designed to determine that the specified first switch element does not open although a first current running through the specified first switch element exceeds a first current threshold and, in response to said determination, to trigger the limiting unit to limit or prevent the second current on the second line.

A method for protecting at least a part of a network segment of an electrical power distribution network has: detecting voltage dips at the intermediate feeding devices of the line arrangements by the voltage dip detection devices; generating and feeding an electrical signal into the line arrangement by the signal generating device at each intermediate feeding device at which one of the voltage dips is detected, the electrical signals having frequencies different from a network frequency of the network segment; receiving the electrical signals via the line arrangements by the receiving devices of the line protection devices; detecting electrical faults on the line arrangement using the electrical signals received by the triggering device of the respective line protection device; and triggering the disconnecting device of the line protection device of the line arrangement, where an electric fault is detected, by the triggering device so that the line arrangement is electrically disconnected from the further element.

A circuit breaker system includes a first circuit breaker and a second circuit breaker. The first circuit breaker has a first trip unit, a first control unit, and a first electrical sensor. The first control unit is configured to control the first trip unit. The second circuit breaker has a second trip unit, a second control unit, and a second electrical sensor. The second control unit is configured to control the second trip unit. The first control unit is in communication with the second control unit. The first control unit is configured to monitor the communication with the second control unit to determine whether there is an internal device failure in the second circuit breaker. The first control unit is configured to change the first control unit's standard tripping characteristics to emergency tripping characteristics based on detecting the internal device failure of the second circuit breaker.

A relay array may connect an electrical device (e.g., an inverter, power converter, etc.) to a utility grid. Based on a detection of a power interruption or fault, the relay array may disconnect the electrical device from the grid to ensure safety or reduce damage to the electrical device or grid. The relay array may include one or more electromechanical relays (e.g., latching relays). A safety catch may prevent the latching relay(s) from changing states. The electrical device may be configured to facilitate removal of the safety catch once the ability to change states is desired. The latching relay(s) may also be supplied with a power pulse for changing a state of the latching relay(s). The power pulse may be provided by a power bank that may be maintained with power in case of a power interruption or fault.

A method for identifying a location of a fault in an electrical power distribution network that includes identifying an impedance of an electrical line between each pair of adjacent utility poles, measuring a voltage and a current of the power signal at a switching device during the fault, and estimating a voltage at each of the utility poles downstream of the switching device using the impedance of the electrical line between the utility poles and the measured voltage and current during the fault. The method calculates a reactive power value at each of the utility poles using the estimated voltages, where calculating a reactive power value includes compensating for distributed loads along the electrical line that consume reactive power during the fault, and determines the location of the fault based on where the reactive power goes to zero along the electrical line.