A system for monitoring the integrity of a plurality of ground conductors has a plurality of monitors, with a different monitor associated with each ground conductor. Each monitor includes a voltage sensor which monitors voltage on a closed circuit of the monitor. Upon the voltage sensor sensing an unexpected voltage, a transmitter of the monitor issues an “alarm” signal, which may be wireless (e.g., being sent using LoRaWAN protocol). The transmitter may issue other signals, including a periodic “heartbeat” signal to confirm continued operation of the monitor, and a “movement” signal to indicate movement of the monitor. The monitor may be GPS-enabled, in which case each signal may include the GPS coordinates of the monitor. The signals issued by the transmitter may ultimately be analyzed by an operator via a user interface platform, which may simultaneously display information regarding two or more of the plurality of monitors.

An apparatus for detecting an open neutral condition in a split phase power system is described. The apparatus includes two powered lines providing output electricity to an electrical distribution system and a shared neutral line providing a grounded neutral to the first and second powered lines. The apparatus is configured for detecting when an open neutral condition is present in the split phase power system by determining when a power current is present on one or both of the first and second powered lines while a return current is not present on the neutral line; and in response to detecting that the open neutral condition is present, causing an interrupter to interrupt the power supplied by the first and second powered lines or to generate a signal indicating an open condition.

An apparatus for detecting an open neutral condition in a split phase power system is described. The apparatus includes two powered lines providing output electricity to an electrical distribution system and a shared neutral line providing a grounded neutral to the first and second powered lines. The apparatus is configured for detecting when an open neutral condition is present in the split phase power system by determining when a power current is present on one or both of the first and second powered lines while a return current is not present on the neutral line; and in response to detecting that the open neutral condition is present, causing an interrupter to interrupt the power supplied by the first and second powered lines or to generate a signal indicating an open condition.

A load drive circuit includes a power source terminal (“PST”), a power source and a load terminal connecting a load to the power source. A semiconductor switch connects the PST to the load terminal. A control circuit includes an output terminal for opening/closing the semiconductor switch. A freewheeling circuit includes a freewheeling diode and a protection switch blocks a current from the power source to the semiconductor switch when the power source is connected in a reverse manner. A first terminal connects the control circuit to a first fixed potential and a second terminal connects an anode of the freewheeling diode to a second fixed potential. A connection circuit includes a connection switch connecting the output terminal and the first terminal. The connection circuit connects the output terminal to the first terminal when a rise in a potential difference between the first terminal and the second terminal is detected.

A fault protection arrangement. The fault protection arrangement may include a neutral grounding resistor including a first non-ground end, connected to a neutralizing point, and a second non-ground end. The fault protection arrangement may include a neutral grounding resistance monitor assembly, directly coupled to the second non-ground end of the neutral grounding resistor. The neutral grounding resistance monitor assembly may include comprising a signal source coupled to the neutralizing-point; a first current sense circuit coupled between the signal source and the neutralizing-point; a first voltage sense circuit coupled between the signal source and the neutralizing-point; a second current sense circuit, comprising a current sensor, coupled between the second non-ground end of the neutral grounding resistor and a protective earth connection.

An apparatus for detecting an open neutral condition in a split phase power system is described. The apparatus includes two powered lines providing output electricity to an electrical distribution system and a shared neutral line providing a grounded neutral to the first and second powered lines. The apparatus is configured for detecting when an open neutral condition is present in the split phase power system by determining when a power current is present on one or both of the first and second powered lines while a return current is not present on the neutral line; and in response to detecting that the open neutral condition is present, causing an interrupter to interrupt the power supplied by the first and second powered lines or to generate a signal indicating an open condition.

An apparatus for detecting an open neutral condition in a split phase power system is described. The apparatus includes two powered lines providing output electricity to an electrical distribution system and a shared neutral line providing a grounded neutral to the first and second powered lines. The apparatus is configured for detecting when an open neutral condition is present in the split phase power system by determining when a power current is present on one or both of the first and second powered lines while a return current is not present on the neutral line; and in response to detecting that the open neutral condition is present, causing an interrupter to interrupt the power supplied by the first and second powered lines or to generate a signal indicating an open condition.

A system for safely obtaining electrical power from a solar array in a grid-down situation is disclosed. The system may include an array of solar panels, an inverter, a rapid shutdown transmitter, a transformer, and a switch. First wiring may extend to electrically connect the array of solar panels to the inverter. The transformer may have an electrical input and an electrical output. The electrical input of the transformer may be connected to receive electrical power from at least one solar panel of the array of solar panels. Second wiring may extend to electrically connect the electrical output of the transformer to the rapid shutdown transmitter. The switch may control delivery of electrical power through the second wiring from the electrical output of the transformer to the rapid shutdown transmitter.

A DC circuit switching apparatus having a novel structure is disclosed that can reduce the number of electromagnetic contactors with a simple structure, and can realize a compact and low-cost apparatus. A DC circuit switching apparatus to be connected between a battery and a load that includes a power supply line that connects between the battery and the load, wherein the power supply line includes a positive electrode-side power supply line and a negative electrode-side power supply line, a main relay is connected to one of the positive electrode-side power supply line and the negative electrode-side power supply line, and an active fuse is connected to the other of the positive electrode-side power supply line and the negative electrode-side power supply line.

The present disclosure discloses a device and a method for condition monitoring and protection of rotating electrical motors. The device receives measurements of current flowing in a power line connected to the rotating electrical machine. The device extracts a frequency band content containing information representative of condition of rotor bar from the measured current signal using wavelet filters. Further, the device compares the frequency band contents with a predefined threshold value and identifies a condition of the rotor bars. The condition includes damages caused to the rotor bars. Based on the condition, the IED generates one or more status signals (alarm signals or trip signals). The trip signal is provided to a switch connected to the power line to disconnect the rotating electrical machine.