Method, apparatus, and system for real time reactive power output monitoring and predicting

• US 6,492,801 B1
• Filed: 08/21/2001
• Issued: 12/10/2002
• Est. Priority Date: 08/21/2001
• Status: Active Grant

• Current Assignee: Southern Company Services, Inc. (Southern Company)
• Original Assignee: Southern Company Services, Inc. (Southern Company)
• Inventors: Sims, Thomas R., Noles, Daniel W., Hallmark, Daryl K.
• Primary Examiner(s): Oda, Christine
• Assistant Examiner(s): LEROUX, ETIENNE PIERRE
• Application Number:
  US09/934,365
• Time in Patent Office: 476 Days
• Field of Search: 324/76.13, 324/142, 307/19, 307/52, 307/87, 318/808, 318/809, 322/6, 322/20, 322/25, 323/205
• US Class Current: 324/142
• CPC Class Codes: H02J 3/1885 using rotating means, e.g. synchronous generators
• CPC Class Codes: Y02E 40/30 Reactive power compensation

Abstract

An actual real-time reactive power output reserve of a generator is calculated by determining a real-time reactive power output of the generator at present operating conditions, determining a maximum reactive power output of the generator at the present operating conditions based on a maximum volt-ampere output capability of the generator, a real-time transmission voltage level of a transmission system connected to the generator, and a real-time maximum acceptable generator terminal voltage, and subtracting the real-time reactive power output from the maximum reactive power output. A future near-term reactive power output reserve of the generator is calculated by determining an expected maximum reactive power output of the generator at rated operating conditions based on a rated maximum volt-ampere output capability of the generator, a scheduled transmission voltage level of a transmission system connected to the generator, and a maximum acceptable generator terminal voltage, and subtracting the real-time reactive power output from the expected maximum reactive power output.

Claims

1. A method for determining an actual real-time reactive power output reserve of at least one generator, comprising the steps of:

determining a real-time reactive power output of the generator at a present gas cooling gas pressure;

determining a maximum reactive power output capability of the generator at the present cooling gas pressure; and

determining the real-time reactive power output reserve of the generator by subtracting the real-time reactive power output from the maximum reactive power output capability.

2. The method of claim 1, wherein the real-time reactive power output is determined based on a maximum volt-ampere output capability of the generator at the present cooling gas pressure, a real-time transmission voltage level of a transmission system connected to the generator, and a real-time maximum acceptable generator terminal voltage, including real-time voltage limits associated with station service load buses connected to the generator.

3. The method of claim 1, further comprising predicting a future reactive power output reserve of the generator.

4. The method of claim 3, wherein the step of predicting the future reactive power output reserve comprises:

determining an expected maximum reactive power output capability of the generator at rated cooling gas pressure; and

subtracting the real-time reactive power output from the expected maximum reactive power output capability to obtain the future reactive power output reserve.

5. The method of claim 1, wherein the steps for determining the reactive power output reserve are repeated at regular intervals.

6. The method of claim 1, wherein the steps are performed for a plurality of generators.

7. An apparatus for determining an actual real-time reactive power output reserve of at least one generator, comprising:

means for determining a real-time reactive power output of the generator at a present cooling gas pressure conditions;

means for determining a maximum reactive power output capability of the generator at the present cooling gas pressure; and

means for determining the real-time reactive power output reserve by subtracting the real-time reactive power output from the maximum reactive power output capability.

8. The apparatus of claim 7, wherein the real-time reactive power output capability is determined based on a maximum volt-ampere output capability of the generator at the present cooling gas pressure, a real-time transmission voltage level of a transmission system connected to the generator, and a real-time maximum acceptable generator terminal voltage, including real-time voltage limits associated with station service load buses connected to the generator.

9. The apparatus of claim 7, further comprising means for predicting a future reactive power output reserve.

10. The apparatus of claim 9, wherein the means for predicting the future reactive power output reserve comprises:

means for determining an expected maximum reactive power output capability of the generator at rated cooling gas pressure; and

means for subtracting the real-time reactive power output from the expected maximum reactive power output capability to obtain the future reactive power output reserve.

11. The apparatus of claim 7, wherein the determination of the reactive power output, maximum reactive power output capability, and reactive power output reserve is repeated at regular intervals.

12. The apparatus of claim 7, wherein the reactive power output reserve is determined for a plurality of generators.

13. A system for determining an actual real-time reactive power output reserve;

comprising;

at least one generator;

input means for receiving information from the generator in real time, including information regarding a present cooling gas pressure; and

a processor connected to the input means, wherein the processor determines a real-time reactive power output of the generator at the present cooling gas pressure, determines a maximum reactive power output capability of the generator at the present cooling gas pressure, and determines the real-time reactive power output reserve by subtracting the real-time reactive power output from the maximum reactive power output capability.

14. The system of claim 13, wherein the input means also receives information from a transmission system connected to the generator, and the processor determines the real-time reactive power output capability based on a maximum volt-ampere output capability of the generator at the present cooling gas pressure, a real-time transmission voltage level of the transmission system connected to the generator, and a maximum acceptable generator terminal voltage, including real-time voltage limits associated with station service load buses connected to the generator.

15. The system of claim 13, wherein the processor predicts a future reactive power output reserve of the generator.

16. The system of claim 15, wherein for predicting the future reactive power output reserve, the processor determines an expected maximum reactive power output capability of the generator at rated cooling gas pressure and subtracts the real-time reactive power output from the expected maximum reactive power output capability to obtain the future reactive power output reserve.

17. The system of claim 13, wherein the processor repeats the determination of the real-time reactive power output, the maximum reactive power output capability, and the real-time reactive power output reserve at regular intervals.

18. The system of claim 13, wherein the reactive power output reserve is determined for a plurality of generators.