US3903399A
Expired / Lapsed
US
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System and method for converging iterations in a hybrid loadflow computer arrangement
Assignee: Westinghouse Electric Corp
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Filing: 1971-08-26
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Granted: 1975-09-02
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Expires: 1991-08-26
Abstract
Abstract A hybrid loadflow computer arrangement includes an analog network simulator and a digital computer which acquires and processes on-line data and operator data related to the power system for which a loadflow problem is being solved. The analog simulator includes modular circuits representative of power system busses and lines and the interface between the digital computer and the analog network simulator is provided by analogto-digital and digital-to-analog converters and by line outage contact closure outputs. The hybrid arrangement operates iteratively, with the analog network simulator providing a bus voltage solution for a set of network simultaneous equations and the digital computer providing bus load and generation injection current calculations and convergence steering control. To converge the solution, the digital computer is programmed to change the generation reactive power at voltage regulated busses in each iteration as a function of the difference between the analog computed bus voltage and a specified bus voltage.
Inventors
- 👤 Mark K Enns
- 👤 Jorge E Petit
- 👤 Jerry C Russell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 13:15
CPC Classifications
G; G06; G06G; G06G7/00; G06G7/48; G06G7/62; G06G7/63; G06J; G06J1/00
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
289 words
A hybrid loadflow computer arrangement comprising a DC analog simulator of an AC network, said simulator including a plurality of bus DC circuits and line DC circuits interconnected to correspond to the AC network, digital means for generating bus generation and load current values as a function of predetermined parameters including stored bus power and voltage data, an analog output system for converting digital outputs to analog outputs, said digital means including means for causing said analog output system to generate phasor current signals representative of the digitally determined bus generation and load currents, means for applying the phasor bus geneRation and load current signals to the corresponding bus DC circuits, each of said bus DC circuits including means for responding to line phasor current and bus generation and load phasor input current signals and for generating an output bus voltage phasor signal, each of said line DC circuits including means for responding to the difference between applied bus voltage phasor signals and generating an output line phasor current signal in accordance at least with a representation of the equivalent series branch line impedance, means for applying bus voltage phasor signals to said digital means said digital means generating bus generation and load current values in successive iterations after a startup iteration as a function of bus voltage values determined in the next preceding iteration, said digital means further generating the bus generation and load current values as a function of bus reactive powers, means for generating new voltage regulated bus reactive power values in each iteration as a function of computed bus voltage signal representations from the last iteration so as to converge the iterative process to a solution, and means for sensing when a solution is reached.
Claim 2
Dependent Claim
289 words
A hybrid loadflow computer arrangement comprising a DC analog simulator of an AC network, said simulator including a plurality of bus DC circuits and line DC circuits interconnected to correspond to the AC network, digital means for generating bus generation and load current values as a function of predetermined parameters including stored bus power and voltage data, an analog output system for converting digital outputs to analog outputs, said digital means including means for causing said analog output system to generate phasor current signals representative of the digitally determined bus generation and load currents, means for applying the phasor bus geneRation and load current signals to the corresponding bus DC circuits, each of said bus DC circuits including means for responding to line phasor current and bus generation and load phasor input current signals and for generating an output bus voltage phasor signal, each of said line DC circuits including means for responding to the difference between applied bus voltage phasor signals and generating an output line phasor current signal in accordance at least with a representation of the equivalent series branch line impedance, means for applying bus voltage phasor signals to said digital means said digital means generating bus generation and load current values in successive iterations after a startup iteration as a function of bus voltage values determined in the next preceding iteration, said digital means further generating the bus generation and load current values as a function of bus reactive powers, means for generating new voltage regulated bus reactive power values in each iteration as a function of computed bus voltage signal representations from the last iteration so as to converge the iterative process to a solution, and means for sensing when a solution is reached.
Claim 3
Dependent Claim
49 words
A hybrid overflow computer arrangement as set forth in claim 1 wherein said digital means is a programmed digital computer and said digital computer having means for controlling its sequential programmed operation including the programmed operation of said digital generating means, said sensing means, and said analog causing means.
Claim 4
Dependent Claim
78 words
A hybrid loadflow computer arrangement as set forth in claim 2 wherein said digital computer further includes means for generating specified voltages for the network busses including acquired on-line voltage values for at least some of the busses, means for differencing at least voltage regulated bus voltage signal representations with the respective specified bus voltages, and means for determining the voltage regulated bus reactive power values as a function of the voltage differences for the voltage regulated busses.
Claim 5
Dependent Claim
25 words
A hybrid overflow computer arrangement as set forth in claim 3 wherein the convergence function includes a predetermined gain factor for each voltage regulated bus.
Claim 6
Dependent Claim
47 words
A hybrid overflow computer arrangement as set forth in claim 4 wherein the gain factor includes one element having a value common to all voltage regulated busses and another element having a value dependent on the maximum real power generation capability of the respective voltage regulated busses.
Claim 7
Dependent Claim
23 words
A hybrid loadflow computer arrangement as set forth in claim 4 wherein the bus gain factor is multiplied against the bus voltage differences.
Claim 8
Dependent Claim
29 words
A hybrid loadflow computer arrangement as set forth in claim 4 wherein bus generation and load currents are determined by the quantity Pp-jQpk divided by the quantity Epk conjugate.
Claim 9
Dependent Claim
25 words
A hybrid loadflow computer arrangement as set forth in claim 2 wherein the convergence function includes a predetermined gain factor for each voltage regulated bus.
Claim 10
Dependent Claim
47 words
A hybrid loadflow computer arrangement as set forth in claim 8 wherein the gain factor includes one element having a value common to all voltage regulated busses and another element having a value dependent on the maximum real power generation capability of the respective voltage regulated busses.
Claim 11
Dependent Claim
32 words
A hybrid loadflow computer arrangement as set forth in claim 2 wherein said digital computer further includes means for retaining voltage regulated bus reactive power within limits as the solution is converged.
Claim 12
Dependent Claim
52 words
A hybrid loadflow computer arrangement as set forth in claim 2 wherein said digital computer further includes means for setting the last on-line solution values of the bus voltage signal representations and the voltage regulated bus reactive powers as the corresponding initial values in the first iteration of a new on-line solution.
Claim 13
Dependent Claim
234 words
An automated method for making on-line loadflow solUtions for an electric power system, the steps of said method comprising sensing representations of at least some on-line values including at least some on-line unit generation power and bus voltage values for the system, storing said on-line values in a programmed digital computer operating the digital computer to generate bus generation and load currents as a function of stored bus power and voltage data, applying phasor signals corresponding to the bus generation and load currents to an analog network simulator which includes DC bus circuits and DC line circuits interconnected to simulate the power system, operating the analog simulator to cause the bus circuits to generate solution bus voltage phasor signals, and operating the digital computer to generate new bus generation and load current values as a function of the stored data and the solution bus voltage phasor signals, operating said digital computer further to generate the bus generation and load current values as a function of bus reactive powers, operating said digital computer to generate new voltage regulated bus reactive power values in each iteration as a function of computed bus voltage signal representations from the last iteration so as to converge the iterative process to a solution, operating said digital computer to sense when a solution is reached, and sequentially controlling the operation of the digital computer in the performance of its program steps.
Claim 14
Dependent Claim
234 words
An automated method for making on-line loadflow solUtions for an electric power system, the steps of said method comprising sensing representations of at least some on-line values including at least some on-line unit generation power and bus voltage values for the system, storing said on-line values in a programmed digital computer operating the digital computer to generate bus generation and load currents as a function of stored bus power and voltage data, applying phasor signals corresponding to the bus generation and load currents to an analog network simulator which includes DC bus circuits and DC line circuits interconnected to simulate the power system, operating the analog simulator to cause the bus circuits to generate solution bus voltage phasor signals, and operating the digital computer to generate new bus generation and load current values as a function of the stored data and the solution bus voltage phasor signals, operating said digital computer further to generate the bus generation and load current values as a function of bus reactive powers, operating said digital computer to generate new voltage regulated bus reactive power values in each iteration as a function of computed bus voltage signal representations from the last iteration so as to converge the iterative process to a solution, operating said digital computer to sense when a solution is reached, and sequentially controlling the operation of the digital computer in the performance of its program steps.
Claim 15
Dependent Claim
81 words
A method as set forth in claim 12 wherein the method steps further comprise operating said digital computer to generate specified voltage values for the network busses including acquired on-line voltage values for at least some of the busses, operating said digital computer to difference at least voltage regulated bus voltage signal representations with the respective specified bus voltage values, and generating the voltage regulated bus reactive power values as a function of the voltage differences for the voltage regulated busses.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-01 | 1979-03-03 | 1979-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-01 | 1983-03-03 | 1983-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-01 | 1987-03-03 | 1987-09-02 | $7700.00 | Window Closed / Lapsed |