A first sense resistor is connected between a fourth terminal of a power source potential of a high-potential region and a first terminal of a ground potential. A second sense resistor is connected between a third terminal of a reference potential of the high-potential region and the first terminal. A comparator is disposed in a low-potential region and uses the ground potential as a reference potential for operation. The comparator compares a voltage between an intermediate potential point of the first sense resistor and an intermediate potential point of the second sense resistor with a predetermined reference voltage. The output of the comparator is input through a control circuit and a level shift circuit to a high-side drive circuit driving an upper-arm IGBT. The output of the comparator is input to a driver circuit driving a lower-arm IGBT.

A first sense resistor is connected between a fourth terminal of a power source potential of a high-potential region and a first terminal of a ground potential. A second sense resistor is connected between a third terminal of a reference potential of the high-potential region and the first terminal. A comparator is disposed in a low-potential region and uses the ground potential as a reference potential for operation. The comparator compares a voltage between an intermediate potential point of the first sense resistor and an intermediate potential point of the second sense resistor with a predetermined reference voltage. The output of the comparator is input through a control circuit and a level shift circuit to a high-side drive circuit driving an upper-arm IGBT. The output of the comparator is input to a driver circuit driving a lower-arm IGBT.

The present disclosure relates to a method for preventing a maloperation of differential protection of an optical fiber caused by saturation of a single Current Transformer (CT) of 3/2 connection. By applying a combination of the differential judgment and the sub-CT current judgment, reliable identification of internal and external faults is ensured, and the problem of misjudging of the internal fault as the external fault can be prevented as well.

An arc fault detection system includes a first current sensor, a second current sensor, a band-pass filter, and a comparator module. The first current sensor, the second current sensor, and the comparator module are each connected to the comparator module by direct leads for biasing a current differential between the first current sensor and the second current sensor using a bias calculated from a frequency component indicative of arc events received from the frequency selector.

A method and arrangement are provided for time synchronization between two geographically separated stationary clocks, such as first and second clocks located respectively at first and second ends of an AC power line. A first representation of an oscillating power line quantity is produced by measuring or recording the power line quantity at the first end of the power line, and time-stamping the first representation by the first clock. A second representation of the same oscillating power line quantity is produced by measuring the power line quantity at the second end of the power line, and time-stamping the second representation by the second clock. The first and second representations are compared to determine a clock offset between the first and second clocks. Based on the comparison, one or both of the first and second clocks are adjusted to reduce the determined clock offset.

A method and arrangement are provided for time synchronization between two geographically separated stationary clocks, such as first and second clocks located respectively at first and second ends of an AC power line. A first representation of an oscillating power line quantity is produced by measuring or recording the power line quantity at the first end of the power line, and time-stamping the first representation by the first clock. A second representation of the same oscillating power line quantity is produced by measuring the power line quantity at the second end of the power line, and time-stamping the second representation by the second clock. The first and second representations are compared to determine a clock offset between the first and second clocks. Based on the comparison, one or both of the first and second clocks are adjusted to reduce the determined clock offset.

Techniques for detecting electrical arcing in an electrical system include receiving, by a network device, first voltage or current readings associated with a first site; receiving, by the network device, second voltage or current readings associated with a second site; determining, by the network device, whether an electrical arcing condition is associated with the first site or the second site by comparing the first voltage or current readings with the second voltage or current readings; and performing, by the network device, a remedial operation in response to determining that the electrical arcing condition is associated with the first site.

Techniques for detecting electrical arcing in an electrical system include receiving, by a network device, first voltage or current readings associated with a first site; receiving, by the network device, second voltage or current readings associated with a second site; determining, by the network device, whether an electrical arcing condition is associated with the first site or the second site by comparing the first voltage or current readings with the second voltage or current readings; and performing, by the network device, a remedial operation in response to determining that the electrical arcing condition is associated with the first site.

A solution is disclosed for providing fault-managed power systems using optical elements. The fault-managed power systems are able to provide safe and efficient power delivery utilizing optical fiber links to improve signal integrity, security, and reach of the system.

A solution is disclosed for providing fault-managed power systems using optical elements. The fault-managed power systems are able to provide safe and efficient power delivery utilizing optical fiber links to improve signal integrity, security, and reach of the system.