Methods of an systems for coordinated system-wise energy balancing in the control of bulk power transfer

Claim 1

The method of automatically computing a control quantity for each of the interconnected areas of a multi-area power system such that the control quantities will be indicAtive respectively of the changes in generation required in each of the areas of the power system to tend to maintain the average interchange of power over interconnecting the tie-lines of each area on a predetermined schedule by reducing toward zero accumulated inadvertent interchange of each area and simultaneously to tend to maintain the average frequency of the system as a whole at a predetermined value for the correction of time-error in the system, comprising the steps of: generating first quantities for each area in accordance with the difference between a quantity representative of the scheduled net interchange of power and a quantity representative of the measured interchange of power summed with a quantity representative of the quotient of the inadvertent interchange (Ia) for the corresponding area over a span of time common to all areas, divided by a time-period divisor (H) common to all area, generating a second quantity (S) in accordance with the difference between a quantity representative of a desired frequency of the system and a quantity representative of a measured frequency of the system minus a quantity representative of the time integral of that difference over a predetermined time period which is common to all areas multiplied by a quantity representative of a bias-factor common to all areas, generating a third quantity for each area in accordance with the product of said second quantity and a frequency bias setting for the corresponding area, and subtracting said third quantity for each of said areas from the corresponding one of said first quantities for producing said control quantities.

Claim 2

The method of automatically computing a control quantity for each of the interconnected areas of a multi-area power system such that the control quantities will be indicAtive respectively of the changes in generation required in each of the areas of the power system to tend to maintain the average interchange of power over interconnecting the tie-lines of each area on a predetermined schedule by reducing toward zero accumulated inadvertent interchange of each area and simultaneously to tend to maintain the average frequency of the system as a whole at a predetermined value for the correction of time-error in the system, comprising the steps of: generating first quantities for each area in accordance with the difference between a quantity representative of the scheduled net interchange of power and a quantity representative of the measured interchange of power summed with a quantity representative of the quotient of the inadvertent interchange (Ia) for the corresponding area over a span of time common to all areas, divided by a time-period divisor (H) common to all area, generating a second quantity (S) in accordance with the difference between a quantity representative of a desired frequency of the system and a quantity representative of a measured frequency of the system minus a quantity representative of the time integral of that difference over a predetermined time period which is common to all areas multiplied by a quantity representative of a bias-factor common to all areas, generating a third quantity for each area in accordance with the product of said second quantity and a frequency bias setting for the corresponding area, and subtracting said third quantity for each of said areas from the corresponding one of said first quantities for producing said control quantities.

Claim 6

The method of automatically computing a control quantity for each of the interconnected areas of a multi-area power system such that the control quantities will be indicative respectively of the changes in generation required in each of the areas of the power system to tend to maintain the average interchange of power over interconnecting tie-lines of each area on a predetermined schedule by reducing toward zero accumulated inadvertent interchange of each area and simultaneously to tend to maintain the average frequency of the system as a whole at a predetermined value for the correction of time-error in the system, comprising the steps of: generating first quantities for each area in accordance with the difference between a quantity representative of the scheduled net interchange of power and a quantity representative of the measured interchange of power summed with a quantity representative of the quotient of the inadvertent interchange (Ia) for the corresponding area over a span of time common to all areas, divided by a time-period divisor (H) common to all areas, generating a second quantity (S) in accordance with the difference between a quantity representative of a desired frequency of the system and a quantity representative of a measured frequency of the system minus a quantity representative of the time integral of that difference over a predetermined time period which is common to all areas multiplied by a quantity representative of a bias-factor common to all areas, generating a third quantity for each area in accordance with the product of said second quantity and a frequency bias setting for the corresponding area, subtracting said third quantity for each of said areas from the corresponding one of said first quantitIes for producing said control quantities, and changing the generation of each said area in response to said control quantities in amount and direction to reduce in magnitude said control quantities thereby introducing a sustained time-error of magnitude needed to counterbalance the lack of addition to zero of the inadvertent interchanges throughout the interconnection while permitting the measured frequency of the system to be restored to its desired value, the magnitude of the additional corrective action of each area being in proportion to the relative size of that area defined as the ratio of the frequency bias setting of that area to the frequency bias setting of the entire interconnection and when the algebraic sum of inadvertent interchange for all areas is equal to zero further changing generation to bring to zero accumulated time-error.

Claim 7

The method of automatically computing a control quantity for each of the interconnected areas of a multi-area power system such that the control quantities will be indicative respectively of the changes in generation required in each of the areas of the power system to tend to maintain the average interchange of power over interconnecting tie-lines of each area on a predetermined schedule by reducing toward zero accumulated inadvertent interchange of each area and simultaneously to tend to maintain the average frequency of the system as a whole at a predetermined value for the correction of time-error in the system, comprising the steps of: generating first quantities for each area in accordance with the difference between a quantity representative of the scheduled net interchange of power and a quantity representative of the measured interchange of power summed with a quantity representative of the quotient of the inadvertent interchange (Ia) for the corresponding area over a span of time common to all areas, divided by a time-period divisor (H) common to all areas, generating a second quantity (S) in accordance with the difference between a quantity representative of a desired frequency of the system and a quantity representative of a measured frequency of the system minus a quantity representative of the time integral of that difference over a predetermined time period which is common to all areas multiplied by a quantity representative of a bias-factor common to all areas, generating a third quantity for each area in accordance with the product of said second quantity and a frequency bias setting for the corresponding area, subtracting said third quantity for each of said areas from the corresponding one of said first quantitIes for producing said control quantities, and changing the generation of each said area in response to said control quantities in amount and direction to reduce in magnitude said control quantities thereby introducing a sustained time-error of magnitude needed to counterbalance the lack of addition to zero of the inadvertent interchanges throughout the interconnection while permitting the measured frequency of the system to be restored to its desired value, the magnitude of the additional corrective action of each area being in proportion to the relative size of that area defined as the ratio of the frequency bias setting of that area to the frequency bias setting of the entire interconnection and when the algebraic sum of inadvertent interchange for all areas is equal to zero further changing generation to bring to zero accumulated time-error.