Method and device for determining the absence of voltage in electrical equipment. An installed device is electrically connected to a power source. The installed device has circuitry capable of detecting voltage, performing self-diagnostics, and testing for connectivity to the power source. In one embodiment, the device can also check to see if the voltage is at a deenergized level, recheck for continuity and repeat the self-diagnostics. In another embodiment, the installed device can be electrically connected to the line and load side of a disconnect and have circuitry configured to check the status of the disconnect. In another embodiment, the device can be configured to communicate with a portable reader in order to transfer information to the portable reader. In yet another embodiment, the device can be configured to interact with a controller that controls access to the panel in which the device is installed.

Method and device for determining the absence of voltage in electrical equipment. An installed device is electrically connected to a power source. The installed device has circuitry capable of detecting voltage, performing self-diagnostics, and testing for connectivity to the power source. In one embodiment, the device can also check to see if the voltage is at a deenergized level, recheck for continuity and repeat the self-diagnostics. In another embodiment, the installed device can be electrically connected to the line and load side of a disconnect and have circuitry configured to check the status of the disconnect. In another embodiment, the device can be configured to communicate with a portable reader in order to transfer information to the portable reader. In yet another embodiment, the device can be configured to interact with a controller that controls access to the panel in which the device is installed.

A system for the verification of the absence of voltage includes a first impedance, an amplitude limiter electrically connected to the first impedance, a second impedance electrically connected to the first impedance and the amplitude limiter, a varactor circuit electrically connected to the second impedance, an isolation capacitor electrically connected to the second impedance and varactor circuit, an envelope circuit with a voltage detection circuit connected to the isolation circuit via a buffer, and an RF oscillator. The amplitude limiter configured to limit the voltage applied to the varactor circuit. The RF oscillator configured to interact with the varactor circuit in order to create a modulated circuit for the buffer and envelope circuit. The envelope circuit is configured to demodulate the signal for the voltage detection circuit.

A system for the verification of the absence of voltage includes a first impedance, an amplitude limiter electrically connected to the first impedance, a second impedance electrically connected to the first impedance and the amplitude limiter, a varactor circuit electrically connected to the second impedance, an isolation capacitor electrically connected to the second impedance and varactor circuit, an envelope circuit with a voltage detection circuit connected to the isolation circuit via a buffer, and an RF oscillator. The amplitude limiter configured to limit the voltage applied to the varactor circuit. The RF oscillator configured to interact with the varactor circuit in order to create a modulated circuit for the buffer and envelope circuit. The envelope circuit is configured to demodulate the signal for the voltage detection circuit.

A power black-out sensing system includes: a primary power source providing an alternating current (AC) power using three phase wires and a neutral wire; a secondary power source; a sensing block comprising one or more sensing elements; and a rectifier configured to rectify the AC power from the primary power source and providing a rectified power to the sensing block voltage detector. Two wires of the three phases wires and the neutral wire of the primary power source are connected to rectifier, and a first wire of the two wires is connected to the rectifier via a switch and a second wire of the two wires is directly connected to the rectifier. The sensing block detects a phantom voltage and provides an output signal corresponding the secondary power source during a blackout period.

A permanently installed absence of voltage tester (AVT) may include a connectivity verification system for verifying the connectivity of system cable leads to the main power lines in electrical equipment. An installed AVT may indicate whether the electrical equipment is in an electrically safe state without first requiring direct access to the equipment. One step in the AVT test procedure may include connectivity verification by the connectivity verification system, which may include a sub-procedure to confirm that the installed AVT is directly coupled as intended with direct connection to the equipment being monitored. The connectivity verification system may validate that the AVT is measuring the actual voltage on the power lines of the electrical equipment and has not registered a no-voltage condition due to an unknown disconnection error or installation failure.

A permanently installed absence of voltage tester (AVT) may include a connectivity verification system for verifying the connectivity of system cable leads to the main power lines in electrical equipment. An installed AVT may indicate whether the electrical equipment is in an electrically safe state without first requiring direct access to the equipment. One step in the AVT test procedure may include connectivity verification by the connectivity verification system, which may include a sub-procedure to confirm that the installed AVT is directly coupled as intended with direct connection to the equipment being monitored. The connectivity verification system may validate that the AVT is measuring the actual voltage on the power lines of the electrical equipment and has not registered a no-voltage condition due to an unknown disconnection error or installation failure.

The present disclosure pertains to systems and methods for measuring electrical parameters in an electric power system. In one embodiment, a system may include a line-mounted wireless current sensor comprising a current monitoring subsystem to generate a current measurement of an alternating current flow through an electrical conductor. The line-mounted wireless current sensor may harvest power from the electrical conductor. A processing subsystem may generate a message comprising the current measurement, and the message may be transmitted at a synchronization point using a wireless communication subsystem. An intelligent electronic device (IED) may receive the message. The IED may further generate a voltage and generate a phasor based on the current measurement and the voltage measurement. A control action subsystem may implement a control action (e.g., selectively connecting or disconnecting a capacitor bank) based on the phasor.

The present disclosure pertains to systems and methods for measuring electrical parameters in an electric power system. In one embodiment, a system may include a line-mounted wireless current sensor comprising a current monitoring subsystem to generate a current measurement of an alternating current flow through an electrical conductor. The line-mounted wireless current sensor may harvest power from the electrical conductor. A processing subsystem may generate a message comprising the current measurement, and the message may be transmitted at a synchronization point using a wireless communication subsystem. An intelligent electronic device (IED) may receive the message. The IED may further generate a voltage and generate a phasor based on the current measurement and the voltage measurement. A control action subsystem may implement a control action (e.g., selectively connecting or disconnecting a capacitor bank) based on the phasor.

An electrical safety monitoring system is provided. The system includes an analog circuit having line inputs for hardwiring an L1, an L2, an L3, and a GND three-phase connections, the analog circuit configured to monitor if voltage exists between any two of the line inputs, a heartbeat circuit electrically connected to the analog circuit to provide a heartbeat signal indicative of voltage present on any of the line inputs, an isolated voltage source electrically connected to the heartbeat circuit to power the heartbeat circuit with a VDC+ and a VDC−, and a logic circuit in operative communication with the heartbeat circuit for monitoring input from the heartbeat circuit and decoding the input from the heart beat circuit. The isolated voltage source may be supplied by a programmable logic controller (PLC) and the logic circuit may be implemented within the same PLC as a function block.