Responding to local grid events and distributed grid events

• US 9,368,968 B2
• Filed: 12/28/2012
• Issued: 06/14/2016
• Est. Priority Date: 12/28/2012
• Status: Expired due to Fees

• Current Assignee: Younicos Inc. (Aggreko Ltd.)
• Original Assignee: Younicos Inc. (Aggreko Ltd.)
• Inventors: Schrock, Eric, Jennings, Richard Thomas
• Primary Examiner(s): Amrany, Adi
• Application Number:
  US13/729,801
• Publication Number:
  US 20140183961A1
• Time in Patent Office: 1,264 Days
• Field of Search: 307/44, 307/48, 307/102
• US Class Current: 1/1
• CPC Class Codes: H02J 2310/12 The local stationary network supplying a household or a building
• CPC Class Codes: H02J 3/0012 Contingency detection
• CPC Class Codes: H02J 3/06 Controlling transfer of power between connected networks; Controlling sharing of load between connected networks
• CPC Class Codes: H02J 3/28 Arrangements for balancing of the load in a network by storage of energy
• CPC Class Codes: Y02B 70/3225 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y04S 20/222 Demand response systems, e.g. load shedding, peak shaving

Abstract

A control system for an energy storage device is coupled to sensors on an electrical grid. The control system is configured to receive a measurement from each of the sensors. The control system determines, based on the received measurements, whether a grid event is a local event or a distributed event. The control system selects a response mode for controlling the energy storage device based on whether the grid event is determined to be a local event or a distributed event.

Claims

1. A system comprising:

an energy storage device coupled to an electrical grid;

a plurality of sensors coupled to the electrical grid, the electrical grid comprising a plurality of metering nodes at different geographic locations, each sensor being coupled to a metering node;

a control system coupled to the energy storage device and the sensors, wherein the control system is configured to;

receive a measurement from each of the sensors;

determine, based on the received measurement, whether a grid event is a local event or a distributed event; and

select a response mode for controlling the energy storage device based on whether the grid event is determined to be a local event or a distributed event;

wherein determining whether a grid event is a local event or a distributed event comprises calculating a difference between a first phase angle at a first sensor of the plurality of sensors and a second phase angle at a second sensor of the plurality of sensors, and, if the difference exceeds a threshold, determining that the grid event is a distributed event.

2. The system of claim 1, wherein the control system is configured to:

determine that a first grid event is a local event, and in response, cause the energy storage device to inject or absorb active power at a first rate to compensate for the first grid event; and

determine that a second grid event is a distributed event, and in response, cause the energy storage device to inject or absorb active power at a second rate greater than the first rate to compensate for the second grid event.

3. The system of claim 1, wherein determining whether the grid event is a local event or a distributed event further comprises counting a number of sensors reporting the grid event, and, if the number of sensors is greater than a threshold number of sensors, determining that the grid event is a distributed event.

4. The system of claim 1, wherein the system is configured to determine that the grid event has occurred by determining that at least a first sensor has reported a reduction in a measured electrical parameter of the grid.

5. The system of claim 4, wherein determining that at least a first sensor has reported the reduction in the measure electrical parameter comprises determining that the first sensor has reported the reduction in the measured electrical parameter for at least a threshold period of time.

6. The method of claim 4, wherein determining whether the grid event is a local event or a distributed event further comprises:

receiving location information from each of the sensors; and

determining whether the grid event is a local event or a distributed event based on the location information.

7. The method of claim 6, wherein determining whether the grid event is a local event or a distributed event based on the location information further comprises:

counting a first number of sensors of a first location reporting the grid event;

counting a second number of sensors of a second location reporting the grid event;

determining a difference between the first number of sensors and the second number of sensors; and

determining that the grid event is a local event if the difference is less than or equal to a threshold difference and determining that the grid event is a distributed event if the difference is greater than the threshold difference.

8. A system comprising:

an energy storage device coupled to an electrical grid;

a plurality of sensors coupled to the electrical grid, the electrical grid comprising a plurality of metering nodes at different geographic locations, each sensor being coupled to a metering node;

a control system coupled to the energy storage device and the sensors, wherein the control system is configured to;

receive a measurement from each of the sensors;

determine, based on the received measurement, whether a grid event is a local event or a distributed event; and

select a response mode for controlling the energy storage device based on whether the grid event is determined to be a local event or a distributed event;

wherein determining whether the grid event is a local event or a distributed event comprises;

determining a first power flow from a first sensor of the plurality of sensors to a second sensor of the plurality of sensors;

comparing the first power flow with a recorded power flow from the first sensor to the second sensor, and, if the first power flow is oscillating more than a threshold oscillation amount from the recorded power flow or a rate of change of the power flow relative to the recorded power flow exceeds a rate of change threshold, determine that the grid event is a distributed event.

9. A system comprising:

an energy storage device coupled to an electrical grid;

a plurality of sensors coupled to the electrical grid, the electrical grid comprising a plurality of metering nodes at different geographic locations, each sensor being coupled to a metering node;

a control system coupled to the energy storage device and the sensors, wherein the control system is configured to;

receive a measurement from each of the sensors;

determine, based on the received measurement, whether a grid event is a local event or a distributed event; and

select a response mode for controlling the energy storage device based on whether the grid event is determined to be a local event or a distributed event;

wherein the grid comprises first and second levels of grid components and a first plurality of sensors are located in the first level of grid components and a second plurality of sensors are located in the second level of grid components, and wherein determining whether the grid event is a local event or a distributed event comprises counting a first number of sensors reporting the grid event in the first level and a second number of sensors reporting the grid event in the second level and determining whether the grid event is a local event or a distributed event based on the first number of sensors and the second number of sensors;

wherein determining whether the grid event is a local event or a distributed event based on the first number of sensors and the second number of sensors comprises;

determining a difference between the first number of sensors and the second number of sensors; and

if the difference is greater than a threshold difference, determining that the grid event is a local event, and if the difference is less than or equal to the threshold difference, determining that the grid event is a distributed event.

10. A system comprising:

an energy storage device coupled to an electrical grid;

a plurality of sensors coupled to the electrical grid, the electrical grid comprising a plurality of metering nodes at different geographic locations, each sensor being coupled to a metering node;

a control system coupled to the energy storage device and the sensors, wherein the control system is configured to;

receive a measurement from each of the sensors;

determine, based on the received measurement, whether a grid event is a local event or a distributed event; and

select a response mode for controlling the energy storage device based on whether the grid event is determined to be a local event or a distributed event;

wherein determining whether the grid event is a local event or a distributed event comprises;

receiving location information from each of the sensors;

counting a first number of sensors of a first location reporting the grid event;

counting a second number of sensors of a second location reporting the grid event;

determining a difference between the first number of sensors and the second number of sensors; and

determining that the grid event is a local event if the difference is less than or equal to a threshold difference and determining that the grid event is a distributed event if the difference is greater than the threshold difference.

11. A method comprising:

receiving a measurement from each of a plurality of sensors coupled to an electrical grid, the electrical grid comprising a plurality of metering nodes at different geographic locations, each sensor being coupled to a metering node;

determining, based on the received measurements, whether a grid event is a local event or a distributed event; and

selecting a response mode for controlling an energy storage device coupled to the electrical grid based on whether the grid event is determined to be a local event or a distributed event;

wherein determining whether a grid event is a local event or a distributed event comprises calculating a difference between a first phase angle at a first sensor of the plurality of sensors and a second phase angle at a second sensor of the plurality of sensors, and, if the difference exceeds a threshold, determining that the grid event is a distributed event.

12. The method of claim 11, comprising:

determining that a first grid event is a local event, and in response, causing the energy storage device to inject or absorb active or reactive power at a first rate to compensate for the first grid event; and

determine that a second grid event is a distributed event, and in response, cause the energy storage device to inject or absorb active or reactive power at a second rate greater than the first rate to compensate for the second grid event.

13. The method of claim 11, wherein determining whether the grid event is a local event or a distributed event further comprises counting a number of sensors reporting the grid event, and, if the number of sensors is greater than a threshold number of sensors, determining that the grid event is a distributed event.

14. The method of claim 11, wherein the grid comprises first and second levels of grid components and a first plurality of sensors are located in the first level of grid components and a second plurality of sensors are located in the second level of grid components, and wherein determining whether the grid event is a local event or a distributed event further comprises counting a first number of sensors reporting the grid event in the first level and a second number of sensors reporting the grid event in the second level and determining whether the grid event is a local event or a distributed event based on the first number of sensors and the second number of sensors.

15. The method of claim 14, wherein determining whether the grid event is a local event or a distributed event based on the first number of sensors and the second number of sensors comprises:

determining a difference between the first number of sensors and the second number of sensors; and

if the difference is greater than a threshold difference, determining that the grid event is a local event, and if the difference is less than or equal to the threshold difference, determining that the grid event is a distributed event.

16. The method of claim 11, comprising determining that the grid event has occurred by determining that at least a first sensor has reported a reduction in a measured electrical parameter of the grid.

17. The method of claim 16, wherein determining that at least a first sensor has reported the reduction in the measured electrical parameter comprises determining that the first sensor has reported the reduction in the measured electrical parameter for at least a threshold period of time.