US 9,812,870 B2
Microgrid reactive power management for voltage regulation during and subsequent to islanding
Junhui Zhao, Hamden, CT (US); Di Shi, San Jose, CA (US); and Ratnesh K. Sharma, Fremont, CA (US)
Assigned to NEC Corporation, Tokyo (JP)
Filed by NEC Laboratories America, Inc., Princeton, NJ (US)
Filed on Aug. 19, 2014, as Appl. No. 14/463,204.
Claims priority of provisional application 61/868,127, filed on Aug. 21, 2013.
Prior Publication US 2015/0054339 A1, Feb. 26, 2015
Int. Cl. H02J 3/38 (2006.01); H02J 3/16 (2006.01)
CPC H02J 3/386 (2013.01) [H02J 3/16 (2013.01); H02J 2003/388 (2013.01); Y02E 10/763 (2013.01); Y02E 40/34 (2013.01); Y02P 80/14 (2015.11); Y02P 80/152 (2015.11); Y10T 307/352 (2015.04); Y10T 307/549 (2015.04)] 18 Claims
OG exemplary drawing
 
1. A method for power management, comprising:
determining a voltage level of a grid;
if the voltage level is below a lower voltage threshold, setting power outputs for one or more distributed generators on the grid to maximum; and
if the voltage level is above the lower voltage threshold and below an upper voltage threshold, determining power outputs for one or more distributed generators on the grid using sensitivity-based distributed reactive power compensation by minimizing a sum of power outputs across the distributed generators, wherein a total voltage generated by the one or more distributed generators maintains the voltage level of the grid between the upper and lower voltage thresholds and is the sum of a target bus voltage and a voltage deviation at the bus determined from a voltage sensitivity matrix, the voltage deviation for a bus j being calculated as:

OG Complex Work Unit Drawing
where Dlj is an element of the voltage sensitivity matrix defined as

OG Complex Work Unit Drawing
and ΔQl is a change in reactive power at the bus.