Loading calculation

A system for controlling an electrical power distribution network that includes at least one power source, a primary feeder partitioned into sections by switching devices, and at least one alternate source selectively connectable to one or more of the sections, the system comprising:

• a plurality of switching devices positioned along the feeder, each switching device including:
• (i) sensors configured to obtain time-stamped current measurements and, in some devices, voltage measurements on one or both sides of the device;
• and
• (ii) local processing circuitry configured to compute, at predetermined sample times, power flowing through the device using the obtained measurements;
• a communications interface coupled to the switching devices and configured to disseminate device information, including computed powers and device status, between neighbor devices and to a control device so that, at the end of each dissemination period, the control device possesses up-to-date information for the devices and sections of a division of the feeder;
• a control device implemented in one or more of the switching devices or in a control center and comprising:
• (a) a topology model storing a graph representation that identifies, for each switching device, the section on each device side and the devices on each section, thereby enabling automatic recovery and update of division topology from disseminated device and section (team) data;
• (b) a memory configured to store, for each device side, a fixed-size history of computed powers or underlying measurements from consecutive sample times;
• and
• (c) a median-filter module configured to determine, for each section, a robust section-load estimate as a median over a predetermined number of the most recent section-load computations, where each section load is defined as the sum of power flowing into that section from all devices bounding the section;
• (d) a restoration logic module configured to:
• (1) upon detection of a known topology change that may directly alter section loading, clear at least a portion of the stored history so that subsequent median-filtered section-load estimates reflect post-change conditions more rapidly;
• (2) for any section that is electrically adjacent to a constant-voltage source and lacks source-side measurements, compute an available additional capacity for that source from a maximum source capability, a maximum allowed section load, and a latest robust section-load estimate measured at the section boundary;
• (3) model any distributed generation within a section as negative load such that the section-load estimate represents an algebraic combination of consumption and distributed generation output;
• and
• (4) select and issue switching commands to open and close the switching devices to restore one or more de-energized sections subject to constraints that each energized source and each alternate source can accommodate an aggregate of the robust section-load estimates on the corresponding restored segments, including the computed available additional capacity;
• wherein the control device is further configured to repeat acquisition, estimation, and constraint checking in successive dissemination periods to verify continued compliance with source-capacity constraints during ongoing restoration or reconfiguration.