A node in a power distribution system is described. The node includes an electrical connection to a single-phase power signal from an AC mains power source, a wireless communication interface configured to receive a first phase synchronization message, and a controller. The controller is configured to determine whether the first phase synchronization message is acceptable and detect a zero-crossing event on the single phase power signal subsequent to the receipt of the first phase synchronization message in response to determining that the first phase synchronization message is acceptable. The controller is further configured to calculate a time difference between the receipt of the first phase synchronization signal and the detected zero-crossing event, determine a local phase angle based on the time difference, and establish an identity of the single phase power signal based on the local phase angle.

Systems for determining a phase of a device coupled to an electrical distribution system. The system includes a number of gateway devices configured to transmit a synchronization signal. The gateway device receives a node response message from a first node device that includes a duration value indicating a time between a receipt of the transmitted synchronization signal and a detected zero crossing. The gateway device compares the duration value against duration values received from node devices with a known phase connection and determines a phase of the first node device based on the comparison.

Systems for determining a phase of a device coupled to an electrical distribution system. The system includes a number of gateway devices configured to transmit a synchronization signal. The gateway device receives a node response message from a first node device that includes a duration value indicating a time between a receipt of the transmitted synchronization signal and a detected zero crossing. The gateway device compares the duration value against duration values received from node devices with a known phase connection and determines a phase of the first node device based on the comparison.

A microgrid (MG) controller can control a plurality of distributed generators (DGs) of photovoltaic (PV) arrays. The MG controller can include a power sharing unit configured to share power proportionally in a single current controlled mode (CCM) between the plurality of DGs based on a power capacity for each DG. The power sharing unit can include a robust current droop controller (RCDC) configured to provide proportional active current shared between the plurality of DGs. The power sharing unit can also include a quasi-proportional resonant (QPR) regulator coupled to the RCDC within a unified architecture. The QPR regulator can be configured to regulate a reference current signal.

A microgrid (MG) controller can control a plurality of distributed generators (DGs) of photovoltaic (PV) arrays. The MG controller can include a power sharing unit configured to share power proportionally in a single current controlled mode (CCM) between the plurality of DGs based on a power capacity for each DG. The power sharing unit can include a robust current droop controller (RCDC) configured to provide proportional active current shared between the plurality of DGs. The power sharing unit can also include a quasi-proportional resonant (QPR) regulator coupled to the RCDC within a unified architecture. The QPR regulator can be configured to regulate a reference current signal.

The subject matter of this specification can be embodied in, among other things, an apparatus having a housing, a first electrical input port, a second electrical input port, at least one trigger output port, and a synchronization check relay arranged at least partly within the housing and in electrical communication with the first electrical input port, the second electrical input ports, and the at least one trigger output port.

The subject matter of this specification can be embodied in, among other things, an apparatus having a housing, a first electrical input port, a second electrical input port, at least one trigger output port, and a synchronization check relay arranged at least partly within the housing and in electrical communication with the first electrical input port, the second electrical input ports, and the at least one trigger output port.

Systems for determining a phase of a device coupled to an electrical distribution system. The system includes a number of gateway devices configured to transmit a synchronization signal. The gateway device receives a node response message from a first node device that includes a duration value indicating a time between a receipt of the transmitted synchronization signal and a detected zero crossing. The gateway device compares the duration value against duration values received from node devices with a known phase connection and determines a phase of the first node device based on the comparison.

Systems for determining a phase of a device coupled to an electrical distribution system. The system includes a number of gateway devices configured to transmit a synchronization signal. The gateway device receives a node response message from a first node device that includes a duration value indicating a time between a receipt of the transmitted synchronization signal and a detected zero crossing. The gateway device compares the duration value against duration values received from node devices with a known phase connection and determines a phase of the first node device based on the comparison.

Electrically connecting a first node of a first power grid to a second node of a second power grid includes: determining a phase angle of at least one phase of an AC voltage at the first node in the first power grid; determining a phase angle of at least one phase of an AC voltage at the second node in the second power grid; determining a phase angle metric based on comparing the phase angle of the AC voltage in the first power grid to the phase angle of the AC voltage in the second power grid; comparing the phase angle metric to a phase angle threshold; and if the phase angle metric is equal to or exceeds the phase angle threshold, controlling a dispatchable energy source in the first power grid in a P-Q control mode to adjust the phase angle of at least one phase of the AC voltage at the first node.