A method for identifying element failure in capacitor banks is provided. Capacitor bank phase current is measured and a zero-sequence or negative-sequence current is calculated or measured. A three-phase voltage is measured from a three-phase bus voltage transformer and a zero-sequence voltage or negative-sequence voltage is calculated. A compensated unbalance current is calculated and compared to a predetermined acceptable range. A failure is identified where the compensated unbalance current is outside the predetermined acceptable range.

A ground fault detection apparatus is used to detect a ground fault of a three-phase UPS apparatus. The UPS apparatus includes a first filter circuit, an AC/DC conversion circuit, a DC bus, a DC/AC conversion circuit, and a second filter circuit coupled in sequence. The ground fault detection apparatus includes a detection circuit having a first detection end and a second detection end. The first detection end is coupled to the first filter circuit and the second filter circuit, and the second detection end is coupled to an equipment grounding point. The equipment grounding point is coupled to a neutral point of a three-phase power source, and the three-phase power source is coupled to the first filter circuit. The detection circuit indicates whether the UPS apparatus has a ground fault and a location where the ground fault occurs according to a detection voltage between the first detection end and the second detection end.

A ground fault detection apparatus is used to detect a ground fault of a three-phase UPS apparatus. The UPS apparatus includes a first filter circuit, an AC/DC conversion circuit, a DC bus, a DC/AC conversion circuit, and a second filter circuit coupled in sequence. The ground fault detection apparatus includes a detection circuit having a first detection end and a second detection end. The first detection end is coupled to the first filter circuit and the second filter circuit, and the second detection end is coupled to an equipment grounding point. The equipment grounding point is coupled to a neutral point of a three-phase power source, and the three-phase power source is coupled to the first filter circuit. The detection circuit indicates whether the UPS apparatus has a ground fault and a location where the ground fault occurs according to a detection voltage between the first detection end and the second detection end.

An apparatus is disclosed to identify defects in a cable plant including a cable comprises a carriage and a roller attached to the carriage. The roller is configured to sit on a cable plant. A motor is attached to the carriage and is coupled to the roller to cause rotation of the roller in at least a first direction, to cause movement of the carriage across the cable plant. A transmitter is attached to the carriage and an antenna is coupled to the transmitter. The antenna is configured to emit an RF signal under the control of the transmitter. If there is a defect in the cable, the RF signal may enter the cable through a defect. Detection of the RF signal in the cable is indicative of the presence of a defect in the cable and the location of the defect. Methods and systems are also disclosed.

An apparatus is disclosed to identify defects in a cable plant including a cable comprises a carriage and a roller attached to the carriage. The roller is configured to sit on a cable plant. A motor is attached to the carriage and is coupled to the roller to cause rotation of the roller in at least a first direction, to cause movement of the carriage across the cable plant. A transmitter is attached to the carriage and an antenna is coupled to the transmitter. The antenna is configured to emit an RF signal under the control of the transmitter. If there is a defect in the cable, the RF signal may enter the cable through a defect. Detection of the RF signal in the cable is indicative of the presence of a defect in the cable and the location of the defect. Methods and systems are also disclosed.

A method of fault detection and recovery in a tubing string located in a hydrocarbon well, a method of fault protection in a tubing string located in a hydrocarbon well, and an apparatus and system for same. In one aspect, there is provided a method of fault detection and recovery in a tubing string located in a hydrocarbon well, the tubing string having a plurality of valves, each valve having a control unit, each control unit being connected in series to a power-line providing power and communication, each of the control units being independently controllable. The method comprises: detecting a short circuit, fault or failure in one of the control units of the tubing string via an output of the power-line; causing individual control units to be selectively isolated from the power-line via a circuit interrupting device; and determining one or more control unit associated with the short circuit, fault or failure via the output of the power-line while individual control units are selectively isolated from the power-line.

A method of fault detection and recovery in a tubing string located in a hydrocarbon well, a method of fault protection in a tubing string located in a hydrocarbon well, and an apparatus and system for same. In one aspect, there is provided a method of fault detection and recovery in a tubing string located in a hydrocarbon well, the tubing string having a plurality of valves, each valve having a control unit, each control unit being connected in series to a power-line providing power and communication, each of the control units being independently controllable. The method comprises: detecting a short circuit, fault or failure in one of the control units of the tubing string via an output of the power-line; causing individual control units to be selectively isolated from the power-line via a circuit interrupting device; and determining one or more control unit associated with the short circuit, fault or failure via the output of the power-line while individual control units are selectively isolated from the power-line.

An insulation fault response method for a fuel cell vehicle, comprising: when a vehicle starts, detecting whether a fuel cell is in a startup state or not; when the fuel cell is not in the startup state, reading a first insulation resistance detected by a fuel cell control unit and a second insulation resistance detected by a cell management system; when the first insulation resistance indicates that the vehicle is in an insulation fault, executing a first control policy; and when the second insulation resistance indicates that the vehicle in an insulation fault, executing a second control policy, wherein the first control policy is different from the second control policy, and wherein when the first insulation resistance is less than a first threshold and/or the second insulation resistance is less than a second threshold, the vehicle is in an insulation fault.

An insulation fault response method for a fuel cell vehicle, comprising: when a vehicle starts, detecting whether a fuel cell is in a startup state or not; when the fuel cell is not in the startup state, reading a first insulation resistance detected by a fuel cell control unit and a second insulation resistance detected by a cell management system; when the first insulation resistance indicates that the vehicle is in an insulation fault, executing a first control policy; and when the second insulation resistance indicates that the vehicle in an insulation fault, executing a second control policy, wherein the first control policy is different from the second control policy, and wherein when the first insulation resistance is less than a first threshold and/or the second insulation resistance is less than a second threshold, the vehicle is in an insulation fault.

Examples of determining electronic component authenticity via electronic signal signature measurement are discussed. Reference pin identifiers corresponding to pins of a known authentic electronic component are determined. Measurement values corresponding to characteristics of pins of an electronic component are obtained, and pin identifiers based on the measurement values are generated. Accordingly, an indication that the electronic component is authentic can be provided based at least in part on a comparison of the pin identifiers and the reference pin identifiers.