The present disclosure relates to a recloser control that detects islanding based on a continuous analysis of frequency and rate of change of frequency. For example, a recloser control may include protection circuitry that is communicatively coupled to a recloser. The recloser control may receive measurements of an electrical characteristic in an electric power delivery system. The recloser control may determine frequency (F) and a rate of change of frequency (ROCOF) based on the received measurements. The recloser control may detect islanding of a microgrid in the electric power delivery system based at least in part on F and ROCOF. The recloser control may send a signal to the recloser to trip the recloser based on the islanding of the microgrid.

Techniques are disclosed for providing a variable output micro-grid frequency in order to cause loads and producers coupled to a micro-grid to change operating modes/behaviors accordingly. For example, the utility frequency delivered via the micro-grid may be used as a control signal for the purposes of demand response, e.g., increasing or decreasing load, energy storage control, e.g., to cause storage of energy or the discharging of energy, and generator output curtailment as is mandated by generator interconnection standards such as UL1741 for output power curtailment under high frequency.

The current disclosure provides methods and systems for intelligent load management in off-grid AC systems and provides methods and systems to control and prioritize loads, so that supply and demand can be balanced via an extremely robust and reliable system.

The present disclosure relates to a recloser control that provides autosynchronization of a microgrid to an area electric power system (EPS). For example, a recloser control may include an output connector that is communicatively coupled to a recloser at a point of common coupling (PCC) between the area EPS and the microgrid. The recloser control may include a processor that acquires a first set of measurements indicating electrical characteristics of the area EPS and acquires a second set of measurements indicating electrical characteristics of the microgrid. The recloser control may send synchronization signals to one or more distributed energy resource (DER) controllers to synchronize one or more DERs to the area EPS based on the first set of measurements and the second set of measurements.

Techniques are disclosed for providing a variable output micro-grid frequency in order to cause loads and producers coupled to a micro-grid to change operating modes/behaviors accordingly. For example, the utility frequency delivered via the micro-grid may be used as a control signal for the purposes of demand response, e.g., increasing or decreasing load, energy storage control, e.g., to cause storage of energy or the discharging of energy, and generator output curtailment as is mandated by generator interconnection standards such as UL1741 for output power curtailment under high frequency.

A method for designing a distributed communication topology of a micro-grid based on network mirroring and global propagation rates includes the following steps: first, determining the communication connectivity of distributed directed networks in the micro-grid; next, obtaining, for connected directed communication networks, mirror networks thereof based on a mirroring operation, and selecting an optimal distributed directed communication topology corresponding to a maximum performance indicator based on algebraic connectivity and communication costs; solving, for the optimized distributed communication topology, pinned distributed generation sets corresponding to different pinning numbers based on global propagation rates and out-degrees; and finally, establishing a distributed secondary voltage control of the micro-grid based on the optimal distributed communication network and pinned nodes of the micro-grid, to achieve accurate reactive power sharing and average voltage restoration.

The current disclosure provides methods and systems for intelligent load management in off-grid AC systems and provides methods and systems to control and prioritize loads, so that supply and demand can be balanced via an extremely robust and reliable system.

Disclosed herein are multi-source microgrid power supply systems including a rectifier having an incoming line terminal connected to a low-voltage side of a transformer and an outgoing line terminal connected to a DC bus having one terminal connected to the outgoing line terminal of the rectifier, an inverter having an incoming line terminal connected to the DC bus and an outgoing line terminal connected to oil well equipment, a first voltage regulator having an incoming line terminal connected to a photovoltaic array and an outgoing line terminal connected to the DC bus, a second voltage regulator having an incoming line terminal connected to an energy storage unit and an outgoing line terminal connected to the DC bus, and a third voltage regulator having an incoming line terminal connected to a wind power generation unit and an outgoing line terminal connected to the DC bus.

A fault isolating device for use in a microgrid disconnected from a main power grid includes a voltage meter for detecting a voltage anomaly indicative of an electrical fault, a timer for establishing a time window that begins and ends a predetermined time after a voltage anomaly is detected, a switch that is opened at the start of the time window, and a microcontroller that determines whether to leave the switch open to isolate a faulted portion of the microgrid or to close the switch. A plurality of fault isolating devices can be distributed throughout a microgrid to isolate a faulted branch or faulted branches of an islanded microgrid without interfering with normal fuse operation when the microgrid is connected to the main power grid.

The present disclosure relates to a recloser control that provides autosynchronization of a microgrid to an area electric power system (EPS). For example, a recloser control may include an output connector that is communicatively coupled to a recloser at a point of common coupling (PCC) between the area EPS and the microgrid. The recloser control may include a processor that acquires a first set of measurements indicating electrical characteristics of the area EPS and acquires a second set of measurements indicating electrical characteristics of the microgrid. The recloser control may send synchronization signals to a microgrid controller to synchronize the microgrid controller based on the first set of measurements and the second set of measurements.