Systems and methods for distributed synchronization of micro-grids with multiple points of interconnection

A distributed synchronization method for interconnecting a microgrid with adjacent electric power grids at multiple points of interconnections, wherein each distributed generator of the microgrid includes a primary controller, a secondary controller and a synchronization controller along with a primary controller and a secondary controller, wherein a sparse communication network is used to enable the distributed generator exchanging information with each of its neighboring distributed generators within the microgrid through bi-directional communication links, and the distributed generators located at points of interconnections also receive information from the adjacent power grids that connect to the same points of interconnections, comprising the steps of:

• receiving a request to connect to the microgrid from a first identified adjacent power grid in time, wherein the synchronization controllers of the microgrid assigns the distributed generator connecting to the point of interconnection between the microgrid and the first adjacent power grid as a leader distributed generator and only allows the leader distributed generator sending information to each of its neighboring distributed generators, and all remaining distributed generators are assigned as follower distributed generators within the microgrid, wherein the leader distributed generator only accepts information from the first identified adjacent power grid;
• determining a frequency synchronization correction and a voltage synchronization correction by the synchronization controller of the leader distributed generator, based on synchronization parameters received from the first adjacent power grid and nominal frequency and voltage for the leader distributed generator, and achieving consensus on frequency and voltage corrections for synchronization among all distributed generators of the microgrid;
• adjusting active and reactive outputs of the follower distributed generators and the leader distributed generator, by modifying frequency and voltage references for each distributed generator in the microgrid with the determined frequency synchronization correction and voltage synchronization correction after passing through low-pass filters;
• connecting the first adjacent power grid with the microgrid based on when a set of first predetermined synchronization parameter thresholds are satisfied, wherein the set of the first predetermined synchronization parameters thresholds are received from a user of a user input interface in communication with the synchronization controllers of the microgrid;
• reassigning the leader distributed generator as a follower distributed generator and re-enabling its bi-way communications with each of its neighboring distributed generators after connecting the first adjacent power grid with the microgrid;
• and
• iterating synchronizing of each remaining identified adjacent power grid with the above steps, based on a received request to connect to the microgrid from an identified adjacent power grid.

A distributed synchronization system for interconnecting a microgrid with adjacent power grids at multiple points of interconnections, wherein each distributed generator of the microgrid includes a synchronization controller along with a primary controller and a secondary controller, wherein a sparse communication network is used to enable the distributed generator exchanging information with each of its neighboring distributed generators within the microgrid through bi-directional communication links, and the distributed generators located at points of interconnections also receive information from the adjacent power grids that connect to the same points of interconnections, comprising:

• a user input interface, such that a user of the user input interface is in communication with the synchronization controllers of the microgrid, and provides a set of first predetermined synchronization parameter thresholds;
• a first identified adjacent power grid sends a request to connect to the microgrid which is received according in time, wherein the synchronization controllers of the microgrid assigns the distributed generator connecting to the point of interconnection between the microgrid and the first adjacent power grid as a leader distributed generator and only allows the leader distributed generator sending information to each of its neighboring distributed generators, and all remaining distributed generators are assigned as follower distributed generators within the microgrid, wherein the synchronization controller of the leader distributed generator is configured to determine a frequency synchronization correction and a voltage synchronization correction, based on synchronization parameters received from the first adjacent power grid and nominal frequency and voltage for the leader distributed generator, and achieving consensus on frequency and voltage corrections for synchronization among all distributed generators of the microgrid;
• adjust active and reactive outputs of the follower distributed generators and the leader distributed generator, by modifying frequency and voltage references for each distributed generator in the microgrid with the determined frequency synchronization correction and voltage synchronization correction after passing through low-pass filters;
• connect the first adjacent power grid with the microgrid based on when the set of first predetermined synchronization parameter thresholds are satisfied;
• reassigns the leader distributed generator as a follower distributed generator and re-enabling its bi-way communications with each of its neighboring distributed generators after connecting the first adjacent power grid with the microgrid;
• and
• iterate synchronizing of each remaining identified adjacent power grid with the above steps, based on a received request to connect to the microgrid from an identified adjacent power grid.