A method for controlling a power system control area according to a first and a second control performance standard, wherein operation of the control area determines area control parameter values. The method comprises (a) determining a first compliance target for the first performance standard and a second compliance target for the second performance standard (100/200); (b) determining a first performance standard statistical measure responsive to the control area parameter values from a beginning of a first compliance period to a time at which the first average is determined (108); (c) determining a second performance standard statistical measure responsive to the control area parameter values from a beginning of a second compliance period to a time at which the second average is determined; (d) determining a first area control parameter target responsive to the first performance standard statistical measure (116); (e) determining a second area control parameter target responsive to the second performance standard statistical measure (204); (f) determining a first area control parameter correction responsive to the first area control parameter target and the area control parameter values (150); (g) determining a second area control parameter correction responsive to the second area control parameter target and the area control parameter values (228) and (h) controlling the power system according to one or both of the first and the second area control parameter corrections (154/232).
Description
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is explained in the following description in view of the drawings that show:
FIG. 1 is a block diagram of elements of a power system to which the teachings of the present invention can be applied.
FIGS. 2 and 3 are software flowcharts illustrating the process for determining the predictive CPS1 and CPS2 values according to the teachings of the present invention.
Claims
1. A method for controlling a power system control area according to a control performance standard, wherein operation of the control area determines area control parameter values and control performance standard values, the method comprising:
(a) determining a control performance standard compliance target;(b) determining a statistical measure of control performance standard values from a beginning of a compliance period to a time t at which the statistical measure is determined;(c) determining an area control parameter target responsive to the statistical measure;(d) determining a relationship between the area control parameter values and the area control parameter target over a prior time interval;(e) determining an area control parameter correction responsive to the relationship determined at a step (d);(f) controlling the power system control area responsive to the area control parameter correction; and(g) periodically repeating steps (b)-(f) until an end of the compliance period.
2. The method of claim 1 wherein the statistical measure comprises an average of the control performance standard values, and a step (b) further comprises;
(b1) determining an average of the area control parameter values over a one minute time interval;(b2) determining an average of frequency bias values over the one minute time interval;(b3) determining an average of frequency deviation values over the one minute time interval;(b4) determining the average control performance standard responsive to the average values determined at steps (b1)-(b3).
3. The method of claim 1 wherein the step (d) further comprises determining an average of the area control parameter values over the prior time interval and determining a difference between the average of the area control parameter values during the prior time interval and the area control parameter target, the difference representing the relationship.
4. The method of claim 3 wherein the prior time interval comprises a number of automatic generation control cycles from a beginning of an immediately prior minute to the time at which the average is determined.
5. The method of claim 1 wherein the step (d) further comprises determining instantaneous area control parameter values during the prior time interval and accumulating a difference between each of the instantaneous area control parameter values and the area control parameter target, the difference representing the relationship.
6. The method of claim 5 wherein the prior time interval comprises a number of automatic generation control cycles from a beginning of an immediately prior minute to the time at which the average is determined.
7. The method of claim 1 wherein the control performance standard values are responsive to an average of area control error values over a defined time interval and an average of frequency difference values over a defined time interval.
8. The method of claim 1 wherein the statistical measure comprises an average, the control performance standard comprises a CPS1 control performance standard, the compliance target comprises 100% and the compliance period comprises one year.
9. The method of claim 1 wherein the statistical measure is responsive to an assumed probability density function for the control performance standard, the control performance standard comprises a CPS2 control performance standard, the compliance target comprises 90% and the compliance period comprises one calendar month.
10. The method of claim 1 wherein the area control parameter values comprise ACE values and the area control parameter target comprises an ACE target.
11. The method of claim 1 wherein a step (f) further comprises controlling the power system control area responsive to the area control parameter correction within constraints imposed by operation of the power system control area.
12. The method of claim 1 wherein the beginning of the compliance period of a step (b) further comprises a beginning of a month eleven months prior to the current month and the end of the compliance period of a step (g) further comprises an end of the current month, wherein the compliance period comprises twelve months.
13. The method of claim 1 wherein the steps (b) and (c) are executed once per clock minute and the steps (d) through (f) are executed for each automatic generation control cycle.
14. The method of claim 13 wherein the steps (d) and (e) are executed at the end of each automatic generation control cycle and the step (f) further comprises controlling the power system control area responsive to the area control parameter correction during a next automatic generation control cycle.
15. The method of claim 14 wherein an automatic generation control cycle comprises four seconds.
16. The method of claim 1 wherein a step (c) further comprises determining an area control parameter target responsive to the statistical measure and multiplying the area control parameter target by a gain multiplier.
17. The method of claim 1 wherein the statistical measure comprises an average and the control performance standard value comprises CPS1 and is determined from
18. The method of claim 1 wherein a step (c) further comprises determining a first actual average performance standard responsive to control performance standard values from a beginning of the compliance period to the time t at which the first actual average is determined, and a second desired average performance standard from the time t to the end of the compliance period, wherein the second desired average is responsive to the first actual average, and wherein the area control parameter target is responsive to the second desired average.
19. The method of claim 18 wherein the first average is determined from
20. The method of claim 19 wherein the term ΔFi comprises an average frequency error for a prior time interval or comprises a largest absolute value clock-minute average frequency error, including a sign of the largest absolute value clock-minute average frequency error.
21. The method of claim 1 wherein the area control parameter target is determined from
ACEt,Target={[(nt+nT-t)(2−pcps1)ε12−ntX1]/nT-t}(−10Bi)/[gΛF×(ΔFi)m]
22. The method of claim 1 wherein the step (b) further comprises;
(b1) determining an average of the area control parameter values over a ten minute time interval;(b2) determining a statistical representation of a plurality of averages of the area control parameters values determined at a step (b1);(b3) determining the statistical measure of the control performance standard values responsive to the steps (b1) and (b2).
23. The method of claim 1 wherein the beginning of the compliance period of a step (b) further comprises a beginning of a current calendar month and the end of the compliance period of a step (g) further comprises an end of the current month.
24. The method of claim 23 wherein the steps (b) and (c) are executed once per ten clock minutes and the steps (d) through (f) are executed for each automatic generation control cycle.
25. The method of claim 1 wherein the control performance standard comprises CPS2 and the statistical measure is determined from
P{|[ ACE10]|≦L10}≧pcps2
26. The method of claim 1 wherein the area control parameter target is determined from
27. A method for controlling a power system control area during a control cycle j of a control interval i according to a control performance standard, wherein operation of the control area determines area control parameter values and control performance standard values, the method comprising:
(a) determining a control performance standard compliance target;(b) determining a statistical measure of the control performance standard responsive to the control performance standard values from a beginning of a compliance period to a time t at which the average is determined;(c) determining an area control parameter upper target and lower target responsive to the statistical measure;(d) determining a first deviation of each area control parameter value from the upper target and a second deviation of each area control parameter value from the lower target, from the beginning of the control interval i to a control cycle j−1;(e) summing the first deviations to produce a first sum and summing the second deviations to produce a second sum;(f) determining an average area control parameter responsive to the area control parameter values from the beginning of the control interval i to the control cycle j−1;(g) determining a relationship between the average area control parameter and the upper target;(h) determining a relationship between the average area control parameter and the lower target; and(i) determining a correction amount to be applied to the area control parameter for the control cycle j, the correction amount responsive to the relationships determined at the steps (g) and (h) and the first and the second sums or determining that a correction amount is not required.
28. The method of claim 27 wherein the relationship of the step (g) comprises the average area control parameter greater than zero and less than the upper target, and wherein responsive to the relationship of the step (g) the step (i) further comprises determining that a correction amount is not required.
29. The method of claim 27 wherein the relationship of the step (h) comprises the average area control parameter less than zero and greater than the lower target, and wherein responsive to the relationship of the step (ha) the step (i) further comprises determining that a correction amount is not required.
30. The method of claim 27 the step (i) further comprising for the average area control parameter greater than the upper target according to the step (g), determining a correction amount of a negative of a quantity including the first sum and the area control parameter of the control cycle j.
31. The method of claim 27 the step (i) further comprising for the average area control parameter greater than the upper target according to the step (g), determining a correction amount of a negative of a quantity including the first sum, a deviation of the area control parameter of the control cycle j from the upper target and the upper target.
32. The method of claim 27 the step (i) further comprising for the average area control parameter less than the lower target, determining a correction amount of a negative of a quantity including the second sum and the area control parameter of the control cycle j.
33. The method of claim 27 the step (i) further comprising for the average area control parameter less than the lower target according to the step (h), determining a correction amount of a negative of a quantity including the second sum, a deviation of the area control parameter of the control cycle j from the lower target and the lower target.
34. The method of claim 27 wherein step (g) further comprises determining a relationship between the average determined at the step (f) and a fraction of the upper target.
35. The method of claim 27 wherein step (h) further comprises determining a relationship between the average determined at the step (f) and a fraction of the lower target.
36. The method of claim 27 wherein the control performance standard comprises CPS1, the statistical measure comprises an average, the compliance target comprises 100%, the compliance period comprises one year, and the upper target is determined according to
ACEiU=|{[(nt+nT-t)(2−pcps1)ε12−ntX1]/nT-t}(−10Bi)/[gΛF×(ΔFi)m]|
37. The method of claim 27 wherein the control performance standard comprises CPS1, the statistical measure comprises an average, the compliance target comprises 100% and the compliance period comprises one year, the upper target is determined according to
ACEiU=|{[(nt+nT-t)(2−pcps1)ε12−ntX1]/nT-t}(−10Bi)/[(ΔFi)]|
38. The method of claim 27 wherein a step (c) further comprises using a gain factor to determine the upper and lower targets.
39. The method of claim 27 wherein the control performance standard comprises CPS2, the statistical measure is responsive to an assumed probability density function for the control performance standard, the control performance standard comprises a CPS2 control performance standard, the compliance target comprises 90% and the compliance period comprises one calendar month, the upper target is determined according to
40. The method of claim 27 wherein the control performance standard comprises CPS2, the statistical measure is responsive to an assumed probability density function for the control performance standard, the compliance target comprises 90% and the compliance period comprises one calendar month, the
41. The method of claim 27 wherein a step (c) further comprises using a gain factor to determine the upper and lower targets.
42. A method for controlling a power system control area according to a first and a second control performance standard, wherein operation of the control area determines area control parameter values, the method comprising:
(a) determining a first compliance target for the first performance standard and a second compliance target for the second performance standard;(b) determining a first performance standard statistical measure responsive to the control area parameter values from a beginning of a first compliance period to a time at which the first average is determined;(c) determining a second performance standard statistical measure responsive to the control area parameter values from a beginning of a second compliance period to a time at which the second average is determined;(d) determining a first area control parameter target responsive to the first performance standard statistical measure;(e) determining a second area control parameter target responsive to the second performance standard statistical measure;(f) determining a first area control parameter correction responsive to the first area control parameter target and the area control parameter values;(g) determining a second area control parameter correction responsive to the second area control parameter target and the area control parameter values; and(h) controlling the power system according to one or both of the first and the second area control parameter corrections.
43. The method of claim 42 wherein the second area control parameter has a higher priority than the first area control parameter, wherein if the first and the second corrections are in a same direction, a correction having the greater value is used according to the step (i), wherein if the first and the second correction are in an opposite direction, the second correction is used according to the step (i), if one of the first and the second corrections is substantially zero, the non-zero correction is used according to the step (i).
44. The method of claim 42 wherein the first area control parameter comprises CPS1 and the second area control parameter comprise CPS2.
45. The method of claim 42 wherein the first compliance target comprises 100%, the first compliance period comprises a calendar year, the second compliance target comprises 90% and the second compliance period comprises a calendar month.
46. An apparatus for controlling a power system control area according to a first and a second control performance standard, the apparatus comprising:
a data base for storing area control parameter values determined from operational parameters of the power system control areaa first module for determining a first measure of a first control performance standard responsive to the operational parameters from a beginning of a first compliance period to the time at which the first measure is determined;a second module for determining a second measure of a second control performance standard responsive to the operational parameters from a beginning of a second compliance period to the time at which the second measure is determined;a third module for determining a first area control parameter target responsive to the first measure and to a compliance target for the first control performance standard, and for determining a second area control parameter target responsive to the second measure and to a compliance target for the second control performance standard;a fourth module for determining a first area control parameter correction responsive to a first area control parameter target and the area control parameter values and for determining a second area control parameter correction responsive to the second area control parameter target and the area control parameter values; anda fifth module for controlling the power system control area according to one or both of the first and the second area control parameter corrections.
47. The apparatus of claim 46 wherein the operational parameters comprise actual and scheduled incoming and outgoing power flows and actual and scheduled interconnection frequency.
48. The apparatus of claim 46 wherein the second area control parameter has a higher priority than the first area control parameter, wherein if the first and the second area control parameter corrections are in a same direction, a correction having the greater absolute value is used by the fifth module, wherein if the first and the second area control parameter corrections are in an opposite direction, the second correction is used by the fifth module, if one of the first and the second area control parameter corrections is substantially zero, a non-zero correction is used by the fifth module.
49. The apparatus of claim 46 wherein the first area control parameter comprises CPS1 and the second area control parameter comprise CPS2.
50. The apparatus of claim 46 wherein the compliance target for the first control performance standard comprises 100%, the first compliance period comprises a calendar year, the compliance target for the second control performance standard comprises 90% and the second compliance period comprises a calendar month.
51. The apparatus of claim 46 wherein the first and the second measures are determined from the beginning of the respective first and second compliance periods to a time t, wherein the fourth module determines the first area control parameter correction responsive to the first area control parameter target and the area control parameter values to the time t and determines the second area control parameter correction responsive to the second area control parameter target and the area control parameter values to the time t.
52. A computer program product for controlling a power system control area during a control cycle j of a control interval i according to a control performance standard, wherein operation of the control area determines area control parameter values and control performance standard values, the computer program product comprising:
a computer usable medium having computer readable program code modules embodied in the medium for controlling the power system control area;a computer readable first program code module for determining a control performance standard compliance target;a computer readable second code module for determining a statistical measure of the control performance standard responsive to the control performance standard values from a beginning of a compliance period to a time t at which the statistical measure is determined;a computer readable third program code module for determining an area control parameter upper target and lower target responsive to the statistical measure;a computer readable fourth program code module for determining a first deviation of each area control parameter value from the upper target and a second deviation of each area control parameter value from the lower target, from the beginning of the control interval i to a control cycle j−1;a computer readable fifth program code module for summing the first deviations to produce a first sum and summing the second deviations to produce a second sum;a computer readable sixth program code module for determining an average area control parameter responsive to the area control parameter values from the beginning of the control interval i to the control cycle j−1;a computer readable seventh program code module for determining a relationship between the average area control parameter and the upper target;a computer readable eighth program code module for determining a relationship between the average area control parameter and the lower target; anda computer readable ninth program code module for determining a correction amount to be applied to the area control parameter for the control cycle j, the correction amount responsive to the relationships determined by the seventh and eighth program code modules and the first and the second sums or determining that a correction amount is not required.
53. A computer program product for controlling a power system control area according to a first and a second control performance standard, wherein operation of the control area determines area control parameter values, the computer program product comprising:
a computer usable medium having computer readable program code modules embodied in the medium for controlling the power system control area;a computer readable first program code module for determining a first compliance target for the first performance standard and a second compliance target for the second performance standard;a computer readable second program code module for determining a first performance standard statistical measure responsive to the control area parameter values from a beginning of a first compliance period to a time at which the first average is determined;a computer readable third program code module for determining a second performance standard statistical measure responsive to the control area parameter values from a beginning of a second compliance period to a time at which the second average is determined;a computer readable fourth program code module for determining a first area control parameter target responsive to the first performance standard statistical measure;a computer readable fifth program code module for determining a second area control parameter target responsive to the second performance standard statistical measure;a computer readable sixth program code module for determining a first area control parameter correction responsive to the first area control parameter target and the area control parameter values;a computer readable seventh program code module for determining a second area control parameter correction responsive to the second area control parameter target and the area control parameter values; anda computer readable eighth program code module for controlling the power system according to one or both of the first and the second area control parameter corrections.
Patent Application
20070213878
