Power generator controller

• US 6,745,109 B2
• Filed: 02/13/2003
• Issued: 06/01/2004
• Est. Priority Date: 08/23/2002
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Kojima, Yasuhiro, Nakamura, Shizuka, Mori, Kazumi, Izui, Yoshio
• Primary Examiner(s): PALADINI, ALBERT WILLIAM
• Application Number:
  US10/365,694
• Publication Number:
  US 20040039490A1
• Time in Patent Office: 474 Days
• Field of Search: 700/287, 700/286, 700/291, 700/28, 700/29, 700/33, 705/412
• US Class Current: 700/291
• CPC Class Codes: G06Q 50/06 Energy or water supply
• CPC Class Codes: H02J 3/241 The oscillation concerning frequency
• CPC Class Codes: Y02E 40/70 Smart grids as climate change mitigation technology in the energy generation sector
• 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

Abstract

A power generator controller includes a power system monitor and a power generator output optimizing part. The power system monitor keeps check on current status of a power system and puts out an electricity demand. The power generator output optimizing part solves an objective function for determining outputs of power generators of the power system at an interval under a supply and demand balancing constraint which imposes agreement between electric power demanded and electric power supplied. The objective function minimizes total costs in power generation. The power generator output optimizing part solves the objective function further considering an automatic frequency control capacity constraint based on an upper limit of rates of change of outputs of power generators of the power system.

Claims

1. A power generator controller comprising:

a power system monitor monitoring current status of each of a plurality of power generators of a power system and demand for electricity from the power system; and

a power-generator-output-optimizing-part solving an objective function in consideration of a balancing constraint balancing supply of power from the generators and demand for electricity from the power system and determining an output of each of the power generators of the power system at each of a plurality of intervals, the objective function requiring minimized total cost of power generation subject to the balancing constraint, wherein the power-generator-output-optimizing-part solves the objective function in further consideration of automatic frequency control (AFC) capacity, based on an upper limit of rate of change of the power output of each of the power generators.

2. The power generator controller according to claim 1, wherein the power-generator-output-optimizing-part solves the objective function incorporating a fuel consumption constraint which requires that total power outputs of the power generators of the power system are in agreement with a target fuel consumption.

3. The power generator controller according to claim 1, including a load-variation-predicting-unit predicting load variations of the power generators of the power system and calculating a predicted control variable, wherein the power-generator-output-optimizing-part solves the objective function incorporating a variable speed flywheel capacity constraint determined in consideration of the predicted control variable.

4. The power generator controller according to claim 1, wherein the power-generator-output-optimizing-part solves the objective function incorporating a frequency deviation constraint that takes into account follow delay of each of the power generators of the power system.

5. The power generator controller according to claim 4, wherein, in solving the objective function incorporating the frequency deviation constraint, the power-generator-output-optimizing-part calculates the power outputs of each of the power generators of the power system at a first of the intervals, without taking account of the frequency deviation constraint, and solves the objective function at a second of the intervals, which is shorter than the first interval, of the outputs of each of the power generators of the power system, taking the frequency deviation constraint into account.

6. The power generator controller according to claim 1, including a control signal transmitter transmitting to separate power plants of the power system the power outputs of each of the power generators of the power system determined by the power-generator-output-optimizing-part.

7. The power generator controller according to claim 1, wherein cost of power generation at each of the power generators of the power system is described as a quadratic function of power outputs of the respective power generators.

8. A power generator controller comprising:

a power system monitor monitoring operative and inoperative states of each of lines connected to a power system including a plurality of power generators and outputting current status of the power system;

a line work scheduler outputting a schedule for work on the lines, the schedule describing a switching schedule of the lines;

a power-system-section-drawing-unit planning future status of the power system, using the current status of the power system and the schedule for work on the lines;

a power-flow-sensitivity-calculating-unit calculating power flow sensitivity of each of the lines for each power generator in each section of the power system, planned by the power-system-section-drawing-unit; and

a power-generator-output-optimizing-part solving an objective function incorporating a power flow constraint and determining the power outputs of each of the power generators of the power system at each of a plurality of intervals, the objective function requiring minimized total cost of power generation by the plurality of power generators of the power system, subject to the power flow constraint of each of the lines, described as the power flow sensitivity of each of the lines for each of the power generators, wherein the power-generator-output-optimizing-part uses the power flow sensitivity calculated by the power-flow-sensitivity-calculating-unit, considering the power flow constraint.

9. The power generator controller according to claim 8, wherein the power-generator-output-optimizing-part solves the objective function incorporating a fuel consumption constraint which requires that total power outputs of the power generators of the power system are in agreement with a target fuel consumption.

10. The power generator controller according to claim 8, wherein the power-generator-output-optimizing-part solves the objective function incorporating an automatic frequency control capacity constraint determined based on an upper limit on rate of change in the power output of each of the power generators of the power system.

11. The power generator controller according to claim 8, including a load-variation-predicting-unit predicting load variations of the power generators of the power system and calculating a predicted control variable, wherein the power-generator-output-optimizing-part solves the objective function incorporating a variable speed flywheel capacity constraint determined in consideration of the predicted control variable.

12. The power generator controller according to claim 8, wherein the power-generator-output-optimizing-part solves the objective function incorporating a frequency deviation constraint that takes into account follow delay of each of the power generators of the power system.

13. The power generator controller according to claim 12, wherein, in solving the objective function incorporating the frequency deviation constraint, the power-generator-output-optimizing-part calculates the power outputs of each of the power generators of the power system at a first of the intervals, without taking account of the frequency deviation constraint, and solves the objective function at a second of the intervals, which is shorter than the first interval, of the outputs of each of the power generators of the power system, taking the frequency deviation constraint into account.

14. The power generator controller according to claim 8, including a control signal transmitter transmitting to separate power plants of the power system the power outputs of each of the power generators of the power system determined by the power-generator-output-optimizing-part.

15. The power generator controller according to claim 8, wherein cost of power generation at each of the power generators of the power system is described as a quadratic function of power outputs of the respective power generators.