Network-cognizant voltage droop control

Patent metadata

Field	Value
Publication number	US-10784682-B2
Application number	US-201815892730-A
Country	US
Kind code	B2
Filing date	Feb 9, 2018
Priority date	Feb 9, 2017
Publication date	Sep 22, 2020
Grant date	Sep 22, 2020

Abstract

The present disclosure provides techniques for network-cognizant droop control in power systems, such as a power distribution system. An example device includes a processor configured to determine, based on (i) a model representing a structure of a power system that includes a plurality of energy resources and (ii) an indication of predicted uncontrollable power injections in the power system, for each controllable energy resource in the plurality of energy resources, a respective value of a first droop coefficient and a respective value of a second droop coefficient. The processor may be further configured to cause at least one controllable energy resource in the plurality of energy resources to modify an output power of the at least one energy resource based on the respective value of the first droop coefficient and the respective value of the second droop coefficient.

First claim

What is claimed is:

1. A device comprising:
at least one processor configured to:
determine, based on (i) a model representing a structure of a power system that includes a plurality of energy resources and (ii) an indication of predicted uncontrollable power injections in the power system, for each controllable energy resource in the plurality of energy resources, a respective value of a first droop coefficient and a respective value of a second droop coefficient; and
cause at least one controllable energy resource in the plurality of energy resources to modify an output power of the at least one energy resource based on the respective value of the first droop coefficient and the respective value of the second droop coefficient, wherein:
the indication of predicted uncontrollable power injections comprises an interval prediction of uncontrollable power injections in the power system, and
the processor is configured to determine the respective value of the first droop coefficient and the respective value of the second droop coefficient by solving a robust optimization problem.

2. The device of claim 1 , wherein the at least one processor is configured to determine the respective value of the first droop coefficient and the respective value of the second droop coefficient based further on a stability margin parameter that represents a likelihood of maintained stability of the power system when the at least one controllable energy resource modifies the output power based on the respective value of the first droop coefficient and the respective value of the second droop coefficient.

3. The device of claim 1 , wherein receiving the model representing the physical connection structure of the power system comprises receiving coefficients of a linear model of voltage values in the power system as a function of active and reactive power production values and load values in the power system.

4. The device of claim 1 , wherein the indication of predicted uncontrollable power injections comprises a point prediction of uncontrollable power injections in the power system.

5. The device of claim 1 , wherein the predicted uncontrollable power injections in the power system comprise predicted uncontrollable power productions and uncontrollable loads.

6. The device of claim 1 , wherein the at least one processor is further configured to:
receive the model; and
receive the indication of predicted uncontrollable power injections.

7. A system comprising:
a power management unit configured to:
determine, based on (i) a model representing a physical connection structure of a power system that includes a plurality of energy resources and (ii) an indication of predicted uncontrollable power injections in the power system, for each controllable energy resource in the plurality of energy resources, a respective value of a first droop coefficient and a respective value of a second droop coefficient; and
output the respective value of the first droop coefficient and the respective value of the second droop coefficient; and

a plurality of controllable energy resources in the plurality of energy resources, wherein each controllable energy resource in the plurality of controllable energy resources is configured to:
receive the respective value of the first droop coefficient and the respective value of the second droop coefficient;
determine a respective voltage value corresponding to a point at which the controllable energy resource is connected to the power system;
determine, based on the respective value of the first droop coefficient, the respective value of the second droop coefficient, and the respective voltage value, a respective value of an active power setpoint and a respective value of a reactive power setpoint; and
modify a respective output power of the controllable energy resource based on at least one of the respective value of the active power setpoint or the respective value of the reactive power setpoint.

8. The system of claim 7 , wherein:
the indication of predicted uncontrollable power injections comprises an interval prediction of uncontrollable power injections in the power system, and
the power management unit is configured to determine the respective value of the first droop coefficient and the respective value of the second droop coefficient by solving a robust optimization problem.

9. The system of claim 7 , wherein the power management unit is configured to determine the respective value of the first droop coefficient and the value of the respective second droop coefficient based further on a stability margin parameter that represents a likelihood of maintained stability of the power system when the plurality of controllable energy resources each modifies the output power based on the respective value of the first droop coefficient and the respective value of the second droop coefficient.

10. The system of claim 7 , wherein the power management unit is configured to receive the model representing the physical connection structure of the power system by receiving coefficients of a linear model of voltage values in the power system as a function of active and reactive power production values and load values in the power system.

11. The system of claim 7 , wherein the indication of predicted uncontrollable power injections comprises a point prediction of uncontrollable power injections in the power system.

12. The system of claim 7 , wherein the predicted uncontrollable power injections in the power system comprise predicted uncontrollable power productions and uncontrollable loads.

13. The system of claim 7 , wherein at least one controllable energy resource in the plurality of controllable energy resources is configured to determine the respective value of the active power setpoint and the respective value of the reactive power setpoint by:
determining a respective candidate value of the active power setpoint and a respective candidate value of the reactive power setpoint; and
projecting the respective candidate value of the active power setpoint and the respective candidate value of the reactive power setpoint onto a respective set of feasible power setpoints for the at least one controllable energy resource.

14. The system of claim 7 , wherein at least one controllable energy resource in the plurality of controllable energy resources is configured to determine the respective value of the active power setpoint and the respective value of the reactive power setpoint based further on at least one respective objective representing a desired limitation on the respective output power of the controllable energy resource.

15. The system of claim 14 , wherein the at least one respective objective represents a desired limitation on real power production, a desired limitation on reactive power production, or a desired limitation on both real and reactive power production.

16. The system of claim 7 , wherein:
the power management unit is configured to iteratively determine the respective value of the first droop coefficient and the respective value of the second droop coefficient at a first frequency; and
each controllable energy resource in the plurality of controllable energy resources is configured to determine the respective value of the active power setpoint and the respective value of the reactive power setpoint at a second frequency that is higher than the first frequency.

17. The system of claim 7 , wherein the power management unit is further configured to:
receive the model; and
receive the indication of predicted uncontrollable power injections in the power

Assignees

• Alliance Sustainable Energy

Inventors

• Baker Kyri Alysa
• Bernstein Andrey
• Dall'Anese Emiliano

Classifications

• H02J2103/30

  Simulating, planning, modelling, reliability check or computer assisted design [CAD] of electric power networks · CPC title

• H02J2101/24

  Photovoltaics · CPC title

• H02J2101/20

  Dispersed power generation using renewable energy sources · CPC title

• H02J3/1892 Primary

  the arrangements being an integral part of the loads or of their control circuits · CPC title

• H02J3/32

  using batteries or super capacitors with converting means · CPC title