The present disclosure provides a method for modifying a gas density relay and a gas density relay having an online self-check function and a check method therefor. The gas density relay having an online self-check function is used for high-voltage and medium-voltage electrical devices, and includes a gas density relay body, a gas density detection sensor, a gas path blocking pressure regulation mechanism, an online check contact signal sampling unit and an intelligent control unit. The intelligent control unit controls a blocking member of the gas path blocking pressure regulation mechanism to move, so as to block a gas path between a first interface and a second interface. Moreover, a volume of a sealed cavity changes, a gas pressure of the gas density relay body slowly falls, thereby generating contact action, the contact action is transmitted to the intelligent control unit by means of the online check contact signal sampling unit, and the intelligent control unit detects an alarm and/or blocking contact signal action value and/or return value according to a density value during the contact action, such that check can be completed without maintenance personnel on site, and the reliability and efficiency of a power grid are greatly improved while cost is lowered.

Examples relate to a current sensor and to a method for sensing a strength of an electric current using two groups of magnetic sensing probes. The current sensor includes a first group and a second group of magnetic sensing probes. The current sensor comprises sensor circuitry coupled to the first and the second group of magnetic sensing probes. The sensor circuitry is configured to determine a first differential magnetic field measurement of a magnetic field using probes of the first group of magnetic sensing probes. The sensor circuitry is configured to determine a second differential magnetic field measurement of the magnetic field using probes of the second group of magnetic sensing probes. The sensor circuitry is configured to determine a strength of the electric current based on a difference between the first differential magnetic field measurement and the second differential magnetic field measurement.

A method of detecting a failure of an antiparallel thyristor, wherein the antiparallel thyristor includes a first thyristor and a second thyristor connected in parallel and in opposite directions, and is configured to control power supplied from an alternating current power supply to a load, the method including: detecting, as a first detection value, a voltage or a current supplied to the load when ceasing an output command for the second thyristor and issuing an output command for the first thyristor; detecting, as a second detection value, the voltage or the current supplied to the load when ceasing the output command for the first thyristor and issuing the output command for the second thyristor; and determining the failure of the antiparallel thyristor based on a difference between the first detection value and the second detection value.

A circuit breaker monitoring system and method includes a vibration sensor, a processing unit, and an output unit. The vibration sensor is configured to be mounted to a circuit breaker and to acquire a temporal vibration signal over at least a temporal portion of a closing operation of the circuit breaker. The closing operation comprises: initiation of the closing operation; latch release; movement of a moveable contact towards a fixed contact; contact touch of the moveable contact with the fixed contact; stop of movement of the moveable contact. The sensor provides the temporal vibration signal to the processing unit, which determines a plurality of physical switch events and corresponding plurality of time points of the plurality of physical switch events over the closing operation of the circuit breaker.

A system and method for monitoring a circuit breaker monitoring system includes a vibration sensor, a processing unit, and an output unit. The vibration sensor is mounted to a circuit breaker acquires a temporal vibration signal over at least a temporal portion of a closing operation of the circuit breaker, wherein the closing operation comprises: initiation of the closing operation, latch release, movement of a moveable contact towards a fixed contact, contact touch of the moveable contact with the fixed contact, and stop of movement of the moveable contact. The vibration sensor provides the temporal vibration signal to the processing unit, which determines a plurality of features of the closing operation and an indication of operational functionality of the circuit breaker.

A method and a device for determining an operating state of an elevator system include determining a current/time profile of a current supplied to the elevator system via a power supply line, identifying at least one current profile segment of the current/time profile, and deriving a current profile pattern of the identified current profile segment. The operating state of the elevator system is determined based on comparing the current profile pattern to at least one reference pattern. The method and the device may also be easily used by personnel without electrical training and may be used in elevator systems that are not known in detail.

The smart circuit breaker tester is a portable system for testing medium voltage circuit breakers. The system includes a programmable logic controller (PLC), a human machine interface (HMI), transducers for measuring current and voltage, an impedance tester, a smart power supply for supplying voltages required for testing circuit breakers with related power and safety components, and plug and play and OEM cables for connecting the system to the circuit breaker under test. The PLC is programmed with custom software that reports such testing criteria as closing time and closing drain current, opening time and opening drain current, contact resistance, etc. within about two minutes, and permits testing automatically in sequence or manually one at a time. The system permits testing in situ while the circuit breaker is still connected to the circuit(s) being protected, or when drawn out.

The invention relates to a switch including a switch housing, a contact system and a base disposed in the switch housing, a resistive element for diagnosing a state of a switch, and at least two terminals leading from the base. The resistive element has a specific resistance value. The resistive element is a conductive material formed on the base, the terminals being electrically connected by the conductive material.

A method of monitoring electrical faults includes processing features of signals output by sensors of a circuit breaker about electrical properties of a circuit coupled with a load and transitioning between states of operation based on the processed features. The states include a normal state, a fault state, and a trip state, wherein the state remains in the normal state until the processed features no longer satisfy normal criteria, after which the state transitions to the fault state, wherein the state transitions back to the normal state when a trip condition is not satisfied, and transitions from the fault state to the trip state when the trip condition is satisfied. The method further includes detecting a warning event when the state transitions from the normal state to the fault state and back to the normal state and outputting a warning event notification upon detection of the warning event.

A meter including a phase conductor connected to a phase line of the network, a cut-off member, and a detection circuit comprising: an injection chain arranged, while the cut-off member is open, to generate a test signal with a predetermined voltage level, and arranged to inject the test signal into the phase conductor downstream from the cut-off member; a measurement chain arranged to measure an intermediate voltage level of the test signal at a measurement point of the injection chain, which point is situated between the generator component and the injection component; a processor component arranged to act as a function of the intermediate voltage level in order to determine whether the circuit breaker is open or closed.