METHOD AND MODEL FOR EVALUATING TRANSMISSION ULTRACAPACITORS IN POWER SYSTEMS

• US 20100057268A1
• Filed: 08/29/2008
• Published: 03/04/2010
• Est. Priority Date: 08/29/2008
• Status: Abandoned Application

• Current Assignee: Electric Power Research Institute Incorporated
• Original Assignee: Electric Power Research Institute Incorporated
• Inventors: Smith, Jeffrey W., Kook, Kyung Soo
• Application Number:
  US12/200,992
• Publication Number:
  US 20100057268A1
• Time in Patent Office: Days
• US Class Current: 700/298
• CPC Class Codes: H01G 11/14 Arrangements or processes for adjusting or protecting hybrid or EDL capacitors emergency protective circuit arrangements specially adapted for capacitors, and effecting automatic switching in the event of an undesired change from normal working conditions H02H7/16; emergency protective circuit arrangements for limiting excess current or voltages without disconnection H02H9/00
• CPC Class Codes: H02J 2203/20 Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
• CPC Class Codes: H02J 3/28 Arrangements for balancing of the load in a network by storage of energy
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors
• CPC Class Codes: Y04S 40/20 Information technology specific aspects, e.g. CAD, simulation, modelling, system security

Abstract

A method and model for evaluating transmission ultracapacitor response in a power system. The method includes the steps of implementing a transmission ultracapacitor model into power system simulation software, simulating a desired condition of a power system, and determining a desired output power of a transmission ultracapacitor to define a control setpoint. The method further includes the steps of determining the transmission ultracapacitor limit, such that the desired output power does not exceed the transmission ultracapacitor limit, responding to the condition by adjusting output according to the control setpoint, and using the output in conjunction with other elements in the power system to determine an overall system response.

Claims

1. A method of evaluating transmission ultracapacitors, comprising the steps of:

(a) implementing a transmission ultracapacitor model into power system simulation software;

(b) simulating a desired condition of a power system;

(c) responding to the condition by adjusting output according to a control setpoint; and

(d) determining an overall system response.

2. The method according to claim 1, further including the step of using simple transfer functions to calculate an equivalent circuit current and losses.

3. The method according to claim 1, further including the step of calculating voltage across a transmission ultracapacitor using:

4. The method according to claim 1, further including the step of calculating current across a transmission ultracapacitor using:

5. The method according to claim 1, further including the step of calculating energy remaining in a transmission ultracapacitor using:

E(t)=E(t−

1)−

Energy(delivered)−

Energy(losses).

6. The method according to claim 1, further including the step of calculating losses.

7. The method according to claim 1, further including the step of calculating a maximum power output.

8. The method according to claim 1, further including the step of calculating a maximum input power.

9. The method according to claim 1, further including the step of determining a desired output power of the transmission ultracapacitor.

10. The method according to claim 1, further including the step of determining a transmission ultracapacitor limit.

11. A method of evaluating transmission ultracapacitors, comprising the steps of:

(a) implementing a transmission ultracapacitor model into power system simulation software;

(b) simulating a desired condition of a power system;

(c) determining a desired output power of a transmission ultracapacitor to define a control setpoint;

(d) determining the transmission ultracapacitor limit, such that the desired output power does not exceed the transmission ultracapacitor limit;

(e) responding to the condition by adjusting output according to the control setpoint; and

(f) using the output in conjunction with other elements in the power system to determine an overall system response.

12. The method according to claim 11, further including the step of using simple transfer functions to calculate an equivalent circuit current and losses by holding a constant voltage across an equivalent capacitance based on energy remaining in the transmission ultracapacitor.

13. The method according to claim 11, wherein the step of determining the transmission ultracapacitor limit includes the step of calculating a maximum power output and maximum input power.

14. The method according to claim 13, wherein the maximum power output is determined using a fixed minimum operating voltage of the transmission ultracapacitor.

15. The method according to claim 13, wherein the maximum input power is determined using a fixed maximum operating voltage of the transmission ultracapacitor.

16. The method according to claim 11, wherein if the desired output exceeds the transmission ultracapacitor limit then the desired output is defined at a point below the limit.