An electronic device comprising a first connector is provided. The first connector is connected to an external device. The first connector includes a first pin and a second pin. The electronic device determines whether the electronic device is electrically connected to the external device according to a voltage level of the first pin. When the electronic device is connected to the external device, the electronic device determines whether to supply power to the external device according to a voltage level of the second pin. A control method thereof is also provided.

A load controller is connected with a residential electric load to regulate electric power drawn by the load from a residential a.c. electric power distribution system via power input terminals of the load. A voltmeter is connected to measure voltage at the power input terminals, and an ammeter is connected to measure electric current at the power input terminals. A microprocessor or microcontroller is programmed to compute a source impedance of the power distribution system as seen from the power input terminals using measured voltage and electric current at the power input terminals. The source impedance may be computed by determining an equivalent source voltage as equal to measured voltage at the power input terminals when the electric current at the power input terminals is zero, and computing the source impedance from measured non-zero electric current at the power input terminals in combination with at least the equivalent source voltage.

A transfer switch selectively couples at least two power sources to a load. The load may be a home, business, or vehicle. A current transformer is coupled to the output of the transfer switch and generates a load measurement signal that is proportional to the current or power output from the transfer switch. A controller receives the load measurement signal and a switch setting describing the operation of the switch. The controller generates data for a status message for display based on the load measurement signal and the switch setting. The status message may describe the power consumption of the load or indicate when an error has occurred.

There is provided a distribution abnormality detecting device that detects a distribution abnormality of partitioned power with identification information, the distribution abnormality detecting device being configured to: determine that the distribution abnormality has occurred when an interval of the identification information detected during power distribution is different from an interval specified by the partitioned power.

A distance protection element for fault coverage through a transformer that introduces a break in the zero-sequence equivalent network is disclosed herein. Voltage and current signals from a delta (low) side of the transformer are obtained and compensated using wye (high) side neutral current and nominal values. The compensated voltage and current signals are used in a distance protection element to detect faults on the wye (high) side of the transformer. The distance protection element may be implemented in a generator protection device as backup distance protection.

A distance protection element for fault coverage through a transformer that introduces a break in the zero-sequence equivalent network is disclosed herein. Voltage and current signals from a delta (low) side of the transformer are obtained and compensated using wye (high) side neutral current and nominal values. The compensated voltage and current signals are used in a distance protection element to detect faults on the wye (high) side of the transformer. The distance protection element may be implemented in a generator protection device as backup distance protection.