AMI based volt-VAR optimization using online model learning

• US 10,642,237 B2
• Filed: 05/04/2018
• Issued: 05/05/2020
• Est. Priority Date: 11/09/2015
• Status: Active Grant

• Current Assignee: Hitachi Energy Limited (Hitachi, Ltd.)
• Original Assignee: ABB Schweiz AG (ABB Limited)
• Inventors: Feng, Xiaoming, Kang, Ning
• Primary Examiner(s): Lee, Thomas C
• Assistant Examiner(s): Tang, Michael
• Application Number:
  US15/971,655
• Publication Number:
  US 20180321650A1
• Time in Patent Office: 732 Days
• CPC Class Codes: G05B 19/042 using digital processors G05B19/05 takes precedence
• CPC Class Codes: G05B 2219/2639 Energy management, use maximum of cheap power, keep peak load low
• CPC Class Codes: H02J 13/00002 characterised by monitoring
• CPC Class Codes: H02J 13/00034 the elements or equipment being or involving an electric power substation
• CPC Class Codes: H02J 2203/20 Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
• CPC Class Codes: H02J 3/00 Circuit arrangements for ac mains or ac distribution networks
• CPC Class Codes: H02J 3/16 by adjustment of reactive power
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H04Q 2209/60 for transmitting utility meters data, i.e. transmission of data from the reader of the utility meter
• CPC Class Codes: H04Q 2213/13544 modeling or simulation, particularly of networks
• CPC Class Codes: H04Q 9/02 Automatically-operated arrangements
• CPC Class Codes: Y02E 40/30 Reactive power compensation
• CPC Class Codes: Y02E 40/70 Smart grids as climate change mitigation technology in the energy generation sector
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 10/00 Systems supporting electrical power generation, transmission or distribution
• CPC Class Codes: Y04S 10/12 Monitoring or controlling equipment for energy generation units, e.g. distributed energy generation [DER] or load-side generation
• CPC Class Codes: Y04S 10/22 Flexible AC transmission systems [FACTS] or power factor or reactive power compensating or correcting units
• CPC Class Codes: Y04S 10/30 State monitoring, e.g. fault, temperature monitoring, insulator monitoring, corona discharge
• CPC Class Codes: Y04S 10/50 Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
• CPC Class Codes: Y04S 40/20 Information technology specific aspects, e.g. CAD, simulation, modelling, system security

Abstract

The present application relates generally to Volt-VAR optimization for power distribution systems having advanced metering infrastructure (AMI). Distributed energy resources (DER) such as photovoltaic arrays are becoming prevalent in distribution systems. These DER systems inject power into the distribution system which can cause unfavorable changes, such as a rise in voltage across the feeder lines of the distribution system. Existing control proposals suffer from a number of shortcomings, drawbacks and disadvantages. In some instances, traditional controllers for distribution systems with DER systems may require information related to the arrangement of the distribution system which is unknown and cannot be provided by the advanced metering infrastructure. There remains a significant need for the apparatuses, methods, systems and techniques disclosed herein.

Claims

1. A power device controller for controlling a power distribution system having at least one feeder, at least one electromechanical device and at least one distributed energy resource without using a power flow model, the controller comprising:

a communication transceiver structured to receive electrical measurements from a plurality of electronic power meters, the transceiver additionally structured to transmit perturbation signals to the at least one electromechanical device, and the transceiver additionally structured to transmit control signals to the at least one electromechanical device and the at least one distributed energy resource;

a memory device structured to store electrical measurements received by the communication transceiver; and

a processing unit structured to receive electrical measurements from the communication transceiver, transmit perturbation signals and control signals to the communication transceiver, receive data stored on the memory device, transmit data to the memory device to be stored, and programmed to;

receive historical measurements generated by the plurality of electronic power meters and the at least one electromechanical device,

determine the sensitivities of system voltages over changes in aggregate real power consumption, aggregate reactive power consumption, aggregate distributed energy resource real power generation, aggregate distributed energy resource reactive power generation, switched capacitor bank reactive power generation and voltage regulator tap position using one of only the historical measurements or, if the historical measurements are determined to be insufficient, a combination of the historical measurements and one or more responses to the perturbation signals,

identify a predictive model based on the determined sensitivities of system voltages, and

transmit at least one command signal to the communication transceiver, the at least one command signal being structured to modify power line characteristics by controlling a setting of one of the at least one electromechanical device or the at least one distributed energy resource.

2. The controller of claim 1 wherein the electrical measurements are at least one of voltage measurements, current measurements, real power measurements, reactive power measurements, and power factor measurements.

3. The controller of claim 1 wherein the electromechanical devices are each one of a switched capacitor bank and a voltage regulator.

4. The controller of claim 3 wherein the setting controlled by the control signal is one of the tap position of the voltage regulators, the on/off status of the switch capacitors, and the power factor setting of the distributed energy resources.

5. The controller of claim 1 wherein the central processing unit is programmed to determine the sensitivities of system voltages over the change in switched capacitor bank reactive power generation and voltage regulator tap position by transmitting a plurality of perturbation signals to the communication transceiver, each perturbation signal being structured to control a setting of one electromechanical device, and receiving electrical measurements from the plurality of electronic power meters generated following each of the perturbation signals.

6. The controller of claim 1 wherein at least one of the at least one distributed energy resource comprises a smart inverter and a DC power source and the communication transceiver transmits controls signals to the smart inverter of the distributed energy resource.

7. The controller of claim 1 wherein the processing unit receives historical measurements generated by the plurality of electronic power meters by receiving electrical measurements from the plurality of electronic power meters, storing the electrical measurements in the memory device, and requesting the electrical measurements from the memory device.

8. The controller of claim 1 wherein the historical electrical measurements taken by the electronic power meters and received by the processing unit are generated by a subset of the plurality of electronic power meters, the subset of the plurality of electronic power meters being selected such that the subset collectively captures the extreme variations on the feeders of the power distribution system.

9. The controller of claim 8 wherein the subset of plurality of electronic power meters is analyzed and selectively modified on at least a weekly basis.

10. The controller of claim 1 wherein at least one of the sensitivities of system voltages over the change in aggregate real power consumption, aggregate reactive power consumption, aggregate distributed energy resource real power generation, aggregate distributed energy resource reactive power generation, switched capacitor bank reactive power generation, and voltage regulator tap position are estimated through regression analysis.

11. The controller of claim 1 wherein sensitivities are calculated for a sub-period within a day, the sub-period being determined by the various combinations of loading levels and DER generation levels.

12. The power distribution system of claim 1 wherein the controller is configured to control the processing unit to transmit the perturbation signals when the distributed energy resources are inactive.

13. A power distribution system comprising:

a distribution substation;

a feeder power line electrically coupled with the distribution substation;

at least one lateral power line electrically coupled with the feeder line;

at least one secondary power line electrically coupled with the at least one of the lateral power lines;

at least one switched capacitor bank electrically coupled with at least one of the feeder power line, one of the lateral power lines, and one of the secondary power lines;

at least one voltage regulator electrically coupled with at least one of the feeder power line, one of the lateral power lines, and one of the secondary power lines;

at least one load system electrically coupled with the respective feeder power line, lateral power line or secondary power line, the load system including an electronic power meter electrically coupled with the respective feeder power line, lateral power lines or secondary power lines, and a distributed energy resource electrically coupled with each electronic power meter; and

a central electronic control system in operative communication with the switched capacitor banks, the voltage regulators, and the distributed energy resources, the central electronic control system being structured to

determine a plurality of control commands including switching commands for the switched capacitors, tap position commands for the voltage regulators, and power factor commands for the distributed energy resources, using a model predictive controller structured to determine the plurality of control commands based upon a predicted aggregate real power demand of the entire feeder, a predicted aggregate reactive power demand of the entire feeder, a predicted aggregate real power generation of the distributed energy resources, a sensitivity matrix, and the predicted real power demand uncertainty range, and

transmit the switching commands to the switched capacitors, the tap position commands to the voltage regulators and the power factor commands to the distributed energy resource devices.

14. The system of claim 13 wherein the sensitivity matrix indicates sensitivity of a voltage of the feeder power line to variation in aggregate real power consumption of the feeder power line, variation in aggregate reactive power consumption of the feeder power line, variation in aggregate real power generation of the distributed energy resources, variation in aggregate reactive power generation of the distributed energy resources, variation in reactive power of the switched capacitor banks, and variation in tap position of the voltage regulators.

15. The power distribution system of claim 13 wherein the central electronic control system is structured to determine portions of the sensitivity matrix indicating sensitivity to variation in reactive power of the switched capacitor banks, and variation in tap position of the voltage regulators of sensitivity matrix by applying controlled perturbation to the power distribution system.

16. The power distribution system of claim 15 wherein the central electronic control system is structured to apply the controlled perturbation to the power distribution system during time intervals when the distributed energy resources are inactive.

17. The power distribution system of claim 14 wherein the central electronic control system is structured to determine at least a portion of the sensitivity matrix indicating sensitivity to variation in aggregate real power consumption of the feeder power line, variation in aggregate reactive power consumption of the feeder power line, variation in aggregate real power generation of the distributed energy resources, variation in aggregate reactive power generation of the distributed energy resources by performing a regression analysis upon a set of multiple measurements of voltage, aggregate real power consumption of the feeder power line, aggregate reactive power consumption of the feeder power line, aggregate real power generation of the distributed energy resources, aggregate reactive power generation of the distributed energy resources, and information of the state of the switched capacitor banks and the voltage regulators over a plurality of time intervals.

18. The power distribution system of claim 17 wherein the plurality of time intervals are selected to include a plurality of combinations of aggregate real power consumption of the feeder power line, aggregate reactive power consumption of the feeder power line, aggregate real power generation of the distributed energy resources, and aggregate reactive power generation of the distributed energy resources.

19. The power distribution system of claim 13 wherein the model predictive controller is structured to determine values of the plurality of control commands such that a predicted voltage of the feeder power line meets a predetermined criterion.

20. The power distribution system of claim 13 wherein the model predictive controller utilizes a linear relationship between variation of voltage of the feeder power line and variation of aggregated real power consumption of the feeder power line, aggregated reactive power consumption of the feeder power line, aggregated real power generation of the distributed energy resources, aggregated reactive power generation of the distributed energy resources, reactive power of the switched capacitors and tap position of the voltage regulators.

21. The power distribution system of claim 13 wherein one or more of power flow information of the power distribution system, phasing information of the at least one lateral power line and at least one secondary power line relative to the feeder power line, and impedance information of the at least one lateral power line and at least one secondary power line relative is unknown to the central electronic control system.