Method and apparatus for damping power oscillations on an electrical grid using networked distributed energy storage systems

• US 10,389,126 B2
• Filed: 10/23/2013
• Issued: 08/20/2019
• Est. Priority Date: 09/13/2012
• Status: Active Grant

• Current Assignee: Stem, Inc.
• Original Assignee: Stem, Inc.
• Inventors: Kearns, Ben, Detmers, James W., Burlinson, Jon, Stevens, Drew
• Primary Examiner(s): Jarrett, Ryan A
• Application Number:
  US14/061,643
• Publication Number:
  US 20140074311A1
• Time in Patent Office: 2,127 Days
• Field of Search: 700297
• CPC Class Codes: H02J 2310/64 The condition being economic, e.g. tariff based load management
• CPC Class Codes: H02J 3/14 by switching loads on to, or off from, network, e.g. progressively balanced loading
• CPC Class Codes: H02J 3/241 The oscillation concerning frequency
• CPC Class Codes: H02J 3/242 using phasor measuring units [PMU]
• CPC Class Codes: H02J 3/38 Arrangements for parallely feeding a single network by two or more generators, converters or transformers
• CPC Class Codes: Y02B 70/3225 Demand response systems, e.g. load shedding, peak shaving
• 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 10/22 Flexible AC transmission systems [FACTS] or power factor or reactive power compensating or correcting units
• CPC Class Codes: Y04S 20/222 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y04S 50/10 Energy trading, including energy flowing from end-user application to grid

Abstract

Embodiments of the present invention include control methods employed in multiphase distributed energy storage systems that are located behind utility meters typically located at, but not limited to, medium and large commercial and industrial locations. These distributed energy storage systems can operate semi-autonomously, and can be configured to develop energy control solutions for an electric load location based on various data inputs and communicate these energy control solutions to the distributed energy storage systems. In some embodiments, one or more distributed energy storage systems may be used to absorb and/or deliver power to the electric grid in an effort to provide assistance to or correct for power transmission and distribution problems found on the electric grid outside of an electric load location. In some cases, two or more distributed energy storage systems are used to form a controlled and coordinated response to the problems seen on the electric grid.

Claims

1. A system for managing power flow related to an electrical grid, comprising:

a first energy storage device located at an electric load location that is in electric communication with a first electric power line located at the electric load location that is connected to at least a portion of an electric power grid, wherein the first energy storage device comprises a first energy source; and

a first controller located at the electric load location that is in communication with the first energy storage device and a first sensor configured to measure an amount of power transmitted through the first electric power line,

wherein the first controller is configured to control a transfer of energy between the first electric power line and the first energy storage device based on information generated by the first sensor,

wherein the first controller is further configured to receive grid power oscillation information derived from measurements made by two or more second sensors, the grid power oscillation information based on one or more sinusoidal oscillations in electric power flowing through the electric power grid, and to control a transfer of energy between the first electric power line and the first energy storage device based on the received grid power oscillation information by injecting to the electric power grid or withdrawing from the electric power grid an amount of energy in accordance with a first waveform selected to dampen the one or more sinusoidal oscillations, and

wherein the two or more second sensors are configured to measure a characteristic of the electric power flowing through the electric power grid.

2. The system of claim 1, wherein the first controller is further configured to control the transfer of energy between the electric power line and the first energy source using a first bidirectional power converter.

3. The system of claim 1, wherein the measured characteristic of the electric power comprises a power angle.

4. The system of claim 1, wherein each of the two or more second sensors further comprises a synchrophasor.

5. The system of claim 1, further comprises:

a third sensor configured to measure a frequency of the power transmitted through the first electric power line, wherein the first controller is configured to control a transfer of energy between the first electric power line and the first energy storage device based on the measured frequency information received from the third sensor.

6. The system of claim 1, further comprising:

a second energy storage device located at the electric load location that is in electric communication with a second electric power line that is connected to at least a portion of the electric power grid, wherein the second energy storage device comprises a second energy source; and

a second controller located at the electric load location that is in communication with the second energy storage device and a third sensor configured to measure an amount of power transmitted through the second electric power line,

wherein the second controller is configured to control a transfer of energy between the second electric power line and the second energy storage device based on information generated by the third sensor, and

wherein the second controller is further configured to receive information relating to measurements made by the two or more second sensors, and control a transfer of energy between the second electric power line and the second energy storage device based the received information.

7. The system of claim 6, wherein the first energy storage device further comprises a first communication device and the second energy storage device further comprises a second communication device, and wherein the first communication device is adapted to communicate with the second communication device.

8. The system of claim 1, further comprising an operation center that is configured to:

receive information from the two or more second sensors, and

transfer a control signal to a first system controller in the first energy storage device, wherein the control signal is derived from the information generated by the two or more second sensors.

9. The system of claim 1, wherein the first energy storage device further comprises a system controller, and the system further comprises:

an optimization engine configured to receive one or more external inputs and create a set of operating parameters based on the one or more external inputs,

wherein the system controller is further configured to receive the created operating parameters and use the operating parameters to control an amount of energy flowing through the first electric power line below a threshold value.

10. The system of claim 9, wherein the set of operating parameters are derived from simulations of energy use at an electric load location in which the first energy storage device is disposed, and the simulations are performed by the optimization engine.

11. The system of claim 9, wherein the one or more external inputs are selected from a group consisting of weather information, sunrise and sunset information, power usage cost information, utility'"'"'s billing period, geographic location, local solar production, local incident light, customer type, electric load location building specifications, grid operator data and time data.

12. The system of claim 1, further comprising:

a second energy storage device located at a second electric load location that is remote from the first electric load location, wherein the second energy storage device is in electric communication with a second electric power line located at the second electric load location that is connected to at least a portion of the electric power grid; and

a second controller located at the second electric load location that is in communication with the second energy storage device,

wherein the second controller is configured to receive second grid power oscillation information that is derived from the measurements made by the two or more second sensors and to control a transfer of energy between the second electric power line and the second energy storage device by injecting to the electric power grid or withdrawing from the electric power grid a second amount of energy in accordance with a second waveform based on the received second grid power oscillation information in order to dampen the one or more sinusoidal oscillations, and

wherein the transfer of energy between the second electric power line and the second energy storage device is synchronized with the transfer of energy between the first electric power line and the first energy storage device.

13. The system of claim 1, wherein the two or more second sensors measure a relative phase angle associated with synchrophasors, and wherein the grid power oscillation information is derived based on detecting that the relative phase angle measured by the two or more second sensors oscillates over time.

14. The system of claim 1, wherein the one or more sinusoidal oscillations in electric power flowing through the electric power grid have a frequency that is a harmonic of a first frequency associated with the electric power grid.

15. A system for managing power flow related to an electrical grid, comprising:

a first energy storage device located at an electric load location that is in electric communication with a first electric power line located at the electric load location that is configured to transmit electric power within at least a portion of an electric power grid, wherein the first energy storage device comprises a first energy source, a first controller located at the electric load location and a first sensor, and the first controller is configured to control a transfer of energy between the first electric power line and the first energy storage device based on information generated by the first sensor;

a second energy storage device located at the electric load location that is in electric communication with a second electric power line that is configured to transmit electric power within at least a portion of the electric power grid, wherein the second energy storage device comprises a second energy source, a second controller located at the electric load location and a second sensor, and the second controller is configured to control a transfer of energy between the second electric power line and the second energy storage device based on information generated by the second sensor; and

a grid services controller that is configured to receive information relating to measurements made by two or more third sensors that are configured to measure a characteristic of the electric power flowing through the electric power grid to different parts of the electric power grid, and to transfer a grid power oscillation control signal to the first controller,

wherein the grid power oscillation control signal is derived from the information generated by the two or more third sensors and based on one or more sinusoidal oscillations in electric power flowing through the electric power grid, and

wherein the first controller is configured to control a transfer of energy between the first electric power line and the first energy storage device based on the grid power oscillation control signal by injecting to the electric power grid or withdrawing from the electric power grid an amount of energy in accordance with a first waveform selected to dampen the one or more sinusoidal oscillations.

16. The system of claim 15, wherein the measured characteristic of the electric power comprises a power angle.

17. The system of claim 15, wherein the system further comprises:

an optimization engine configured to receive one or more external inputs and create a set of operating parameters based on the one or more external inputs,

wherein the first controller is further configured to receive the created operating parameters and use the operating parameters to control an amount of energy flowing through the first electric power line below a threshold value.

18. The system of claim 17, wherein the set of operating parameters are derived from simulations of energy use at an electric load location in which the first energy storage device is disposed, and the simulations are performed by the optimization engine.

19. The system of claim 17, wherein the one or more external inputs are selected from a group consisting of weather information, sunrise and sunset information, power usage cost information, utility'"'"'s billing period, geographic location, local solar production, local incident light, customer type, electric load location building specifications, grid operator data and time data.

20. A method of managing power flow related to an electrical grid, comprising:

receiving, at an electric load location, grid power oscillation information, wherein the grid power oscillation information is derived from information collected by two or more first sensors and is based on one or more sinusoidal oscillations in electric power flowing through the electrical grid, and wherein each first sensor is configured to measure a characteristic of the power transmitted through at least a portion of the electrical grid; and

controlling at the electric load location a transfer of power between a first energy storage device located at the electric load location and the electrical grid by injecting to the electrical grid or withdrawing from the electrical grid an amount of energy in accordance with a first waveform selected to dampen the one or more sinusoidal oscillations based on the received grid power oscillation information.

21. The method of claim 20, further comprising receiving power delivery information from a command source, wherein the power delivery information comprises the frequency of the power transmitted through a second portion of the electric power grid, wherein controlling the transfer of power further comprises controlling the transfer of power between one of the plurality of distributed energy storage devices and an electric power line that is in electrical communication with the portion of the electrical grid based on data received by monitoring the frequency of the power transmitted through the electric power line.

22. The method of claim 20, further comprising:

generating control parameters based on a simulation that is performed using forecast information;

monitor a first rate of energy transfer from an electric line to an electric load location, wherein the electric line is in electrical communication with the portion of the electrical grid; and

control a second rate of energy transfer between the electric line and one of the plurality of distributed energy storage devices based on the control parameters, wherein controlling the second rate of energy transfer alters the first rate of energy transfer.

23. The method of claim 22, wherein the control parameters comprise optimum demand set-points as a function of time and one or more battery curves that comprise a set of time-based battery state-of-charge curves.

24. The method of claim 22, wherein the one or more battery state-of-charge curves comprise a flat battery curve, a continuously varying battery curve, a stepped battery curve, or a forecasted battery curve.

25. The method of claim 22, wherein controlling the transfer of power between the plurality of distributed energy storage devices and the electric power grid further comprises:

receiving a time stamp signal from a time source; and

comparing the time stamp signal with the information derived from the information collected by the two or more first sensors.