US3903402A
Expired / Lapsed
US
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Digital computer program system employed in a hybrid loadflow computer arrangement for monitoring the security of an electric power system
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. A program system employed in the digital computer preprocesses input data, determines automatic and operator contingency cases and provides contingency modified preprocessed data, generates basecase and contingency case steady state loadflow solutions for the preprocessed data, and monitors solution results.
Inventors
- 👤 Jorge E Petit
- 👤 David Egelston
- 👤 Jerry C Russell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 00:49
CPC Classifications
G; G06; G06J; G06J1/00; G06G; G06G7/00; G06G7/48; G06G7/62; G06G7/63
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
195 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 preselected network parameters as a function of other stored network parameters and parameters calculated by or derived from parameters calculated by said analog network simulator, analog input and output systems for transferring signals between said digital means and said analog network simulator, means for generating signal representations of on-line power system data including generation power values and tieline power values and at least some bus voltage values to said digital means, said digital means further including means for preprocessing online and other system data in accordance with predetermined indexing and compression and modification requirements, means for generating an on-line basecase loadflow solution with use of the preprocessed data and with interaction with said analog network simulator, means for monitoring the results of the basecase loadflow solution, means for determining contingency cases to be provided with loadflow solutions, means generating contingency case loadflow solutions, and means for sensing the contingency case data for the contingency case loadflow solutions.
Claim 2
Dependent Claim
195 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 preselected network parameters as a function of other stored network parameters and parameters calculated by or derived from parameters calculated by said analog network simulator, analog input and output systems for transferring signals between said digital means and said analog network simulator, means for generating signal representations of on-line power system data including generation power values and tieline power values and at least some bus voltage values to said digital means, said digital means further including means for preprocessing online and other system data in accordance with predetermined indexing and compression and modification requirements, means for generating an on-line basecase loadflow solution with use of the preprocessed data and with interaction with said analog network simulator, means for monitoring the results of the basecase loadflow solution, means for determining contingency cases to be provided with loadflow solutions, means generating contingency case loadflow solutions, and means for sensing the contingency case data for the contingency case loadflow solutions.
Claim 3
Dependent Claim
19 words
A hybrid loadflow computer arrangement as set forth in claim 1 wherein said digital means is a digital computer.
Claim 4
Dependent Claim
156 words
An automated method for operating a hybrid loadflow coMputer arrangement comprising the steps of using a DC analog simulator of an AC network to calculate predetermined network parameters, using a digital means to generate preseleced network parameters as a function of the analog calculated parameters and other stored parameters, transferring signals between the simulator and the digital means during successive loadflow solution iterations, acquiring on-line power system data including generation power values and tieline power values and at least some bus voltage values, and operating the digital means with steps including preprocessing on-line and other system data in accordance with predetermined indexing and compression and modification requirements, generating an on-line basecase loadflow solution with use of the preprocessed data and with interaction with said analog network simulator, monitoring the results of the basecase loadflow solution, repeating the loadflow solution generation step for contingency cases, and determining the contingency case data for the contingency case loadflow solutions.
Claim 5
Dependent Claim
156 words
An automated method for operating a hybrid loadflow coMputer arrangement comprising the steps of using a DC analog simulator of an AC network to calculate predetermined network parameters, using a digital means to generate preseleced network parameters as a function of the analog calculated parameters and other stored parameters, transferring signals between the simulator and the digital means during successive loadflow solution iterations, acquiring on-line power system data including generation power values and tieline power values and at least some bus voltage values, and operating the digital means with steps including preprocessing on-line and other system data in accordance with predetermined indexing and compression and modification requirements, generating an on-line basecase loadflow solution with use of the preprocessed data and with interaction with said analog network simulator, monitoring the results of the basecase loadflow solution, repeating the loadflow solution generation step for contingency cases, and determining the contingency case data for the contingency case loadflow solutions.
Claim 6
Dependent Claim
39 words
An automated method as set forth in claim 3 wherein a digital computer is programmed to perform the steps of the digital means, and sequentially controlling the operation of the digital computer in the performance of its program steps.
Claim 7
Dependent Claim
35 words
A method as set forth in claim 4 wherein the digital computer operating steps further comprise running the on-line basecase loadflow solutions on a cyclical basis and suspending the basecase loadflow solutions on operator request.
Claim 8
Dependent Claim
24 words
A method as set forth in claim 4 wherein the digital computer operating steps further comprise repeating the monitoring step for contingency case solutions.
Claim 9
Dependent Claim
38 words
A method as set forth in claim 4 wherein the digital computer operating steps further comprise undertaking the contingency case determination step only after completion of on-line basecase solutions and not after completion of contingency case loadflow solutions.
Claim 10
Dependent Claim
27 words
A method as set forth in claim 4 wherein the computer operating steps further comprise bidding for a basecase loadflow solution after determined contingency cases are run.
Claim 11
Dependent Claim
39 words
A method as set forth in claim 4 wherein the computer operating steps further comprise using basecase preprocessed data for contingency case loadflow solutions with data modifications needed to reflect the contingency or contingencies specified for each contingency case.
Claim 12
Dependent Claim
37 words
A method as set forth in claim 4 wherein the computer operating steps further comprise alarming and identifying for printout monitored loadflow solution parameters which exceed limits, and specifying a full loadflow solution printout on operator demand.
Claim 13
Dependent Claim
45 words
A method as set forth in claim 4 wherein the computer operating steps further comprise compressing on-line unit generation values into bus generation values and generator unit spinning reserve values into bus spinning reserve values and generator reactive power limits into bus reactive power limits.
Claim 14
Dependent Claim
23 words
A method as set forth in claim 11 wherein the compression steps further comprises compressing bus spinning reserve values into system spinning reserve.
Claim 15
Dependent Claim
25 words
A method as set forth in claim 11 wherein the compression step further comprises compressing bus real powers and tieline interchange powers into system load.
Claim 16
Dependent Claim
53 words
A method as set forth in claim 13 wherein the computer operating steps further comprise generating preprocessed load bus arrays by multiplying total system load against historic bus load distribution factors to obtain real bus loads and by multiplying the real bus loads against historic bus power factors to obtain reactive bus loads.
Claim 17
Dependent Claim
128 words
A method as set forth in claim 14 wherein the computer operating steps further comprise determining a preprocessed bus voltage array of on-line bus voltages and stored table bus voltages and operator entered voltages, and indexing on-line tieline powers into preprocessed arrays, compressing on-line unit generation values into bus generation values and generatOr unit spinning reserve values into bus spinning reserve values and generator unit reactive power limits into bus reactive power limits, compressing bus real load and bus real power generation and tieline real power into a not bus real power array, compressing stored bus generation reactive power and bus reactive load and tieline reactive load and bus shunt megavars into a net bus reactive power array, and determining net low and high bus reactive power limits.
Claim 18
Dependent Claim
42 words
A method as set forth in claim 4 wherein the computer operating steps further comprise determining a preprocessed bus voltage array of on-line bus voltages and stored table bus voltages and operator entered voltages, and indexing on-line tieline powers into preprocessed arrays.
Claim 19
Dependent Claim
48 words
A method as set forth in claim 4 wherein the computer operating steps further comprise modifying a lines out of service array in accordance with entered actual line outages and causing any line outages to be implemented in the analog simulator, and modifying stored bus shunt admittance accordingly.
Claim 20
Dependent Claim
45 words
A method as set forth in claim 4 wherein the computer operating steps further comprise generating and storing for contingency case data generation any data arrays subject to contingency modification and intermediately or finally developed in the data preprocessing step for an on-line basecase solution.
Claim 21
Dependent Claim
29 words
A method as set forth in claim 4 wherein the computer operating steps further comprise executing an input/output subroutine after each loadflow solution to provide for hybrid data transfer.
Claim 22
Dependent Claim
33 words
A method as set forth in claim 19 wherein the subroutine step further comprises imposing a time delay on computer reading of analog computer solution parameters after computer output of computer calculated parameters.
Claim 23
Dependent Claim
30 words
A method as set forth in claim 19 wherein the subroutine step further comprises packing imaginary and real components of digital computer output parameters into single digital computer output words.
Claim 24
Dependent Claim
32 words
A method as set forth in claim 19 wherein the subroutine step further comprises employing conversion factors on read analog simulator phasor signals to correlate analog simulator scaling with per unit values.
Claim 25
Dependent Claim
30 words
A method as set forth in claim 4 wherein the computer operating steps further comprise determining whether the power system has sufficient reserve as a part of the monitoring step.
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 |