US4741023A
Expired / Lapsed
US
⏱️ 0.0 years remaining
On-line test and diagnostic system for power system stabilizer
Assignee: General Electric Co
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Filing: 1986-12-23
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Granted: 1988-04-26
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Expires: 2006-12-23
Abstract
Abstract A method and apparatus for performing a complete functional test of a power system stabilizer connected to the excitation system of an electrical power generator is disclosed. Two tests are performed, one an on-line modulation test, and the second a system response test. In the on-line modulation test, an internal 0.5 hertz sine wave is generated by a microprocessor which is applied as a frequency modulating input to the continuous wave frequency transducer included in the power system stabilizer. Such a signal acts to stimulate intertie mode oscillations and provide a means of determining the gain and phase shift characteristic of the power system stabilizer. In the second test, a voltage step type of signal is generated and applied to the output of the power system stabilizer where it is then coupled to the excitation system of the generator. This has the effect of stimulating local mode oscillations. The generator response to the local mode oscillation is sensed to determine system damping. Both tests are adapted to verify the operational status of the power system stabilizer and the adequacy of its adjustments. Furthermore, a local terminal and a telephone modem are connected to a communication port associated with the microprocessor for enabling the test to be initiated and the results evaluated either locally or remotely.
Inventors
- 👤 Rodney A. Lawson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 07:31
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/34; G01R31/343; G01R27/00; G01R27/28
Claims Analysis
Total Claims: 45
Claim 1
Independent Claim
110 words
A method of testing an electrical power generating system, comprising the steps of: (a) generating a test signal of a predetermined type at the initiation of a test procedure; (b) coupling the test signal into the system at a predetermined location; (c) sensing and storing signals corresponding to a selected number of system operating parameters both before and after the insertion of the test signal; (d) retrieving the stored signals; and (e) thereafter comparing respective signal characteristics of the retrieved signals, before and after the insertion of the test signal, to determine any differences therebetween and thereby provide an indication of the operational status of said electrical power generating system.
Claim 2
Independent Claim
110 words
A method of testing an electrical power generating system, comprising the steps of: (a) generating a test signal of a predetermined type at the initiation of a test procedure; (b) coupling the test signal into the system at a predetermined location; (c) sensing and storing signals corresponding to a selected number of system operating parameters both before and after the insertion of the test signal; (d) retrieving the stored signals; and (e) thereafter comparing respective signal characteristics of the retrieved signals, before and after the insertion of the test signal, to determine any differences therebetween and thereby provide an indication of the operational status of said electrical power generating system.
Claim 3
Independent Claim
116 words
A method of testing an electrical power generating system including a power system stabilizer, comprising the steps of: (a) generating a test signal of a predetermined type at the initiation of a test procedure; (b) inserting the test signal into the system at the power system stabilizer; (c) sensing and storing signals corresponding to a selected number of system operating parameters both before and after the insertion of the test signal; (d) accessing and retrieving the stored signals; and (e) comparing respective signal characteristics of the retrieved signals before and after the insertion of the test signal to determine any difference therebetween and thereby provide an indication of operational status of said electrical power generating system.
Claim 4
Independent Claim
116 words
A method of testing an electrical power generating system including a power system stabilizer, comprising the steps of: (a) generating a test signal of a predetermined type at the initiation of a test procedure; (b) inserting the test signal into the system at the power system stabilizer; (c) sensing and storing signals corresponding to a selected number of system operating parameters both before and after the insertion of the test signal; (d) accessing and retrieving the stored signals; and (e) comparing respective signal characteristics of the retrieved signals before and after the insertion of the test signal to determine any difference therebetween and thereby provide an indication of operational status of said electrical power generating system.
Claim 5
Dependent Claim
43 words
The method as defined by claim 2 wherein said step (a) of generating a test signal comprises generating a sinusoidal type of test signal at a frequency in the range of the natural frequency of intertie oscillatory modes of the power generating system.
Claim 6
Dependent Claim
27 words
The method as defined by claim 3 wherein the frequency of the sinusoidal type test signal is in the range between and including 0.2 and 0.5 hertz.
Claim 7
Dependent Claim
20 words
The method as defined by claim 3 wherein said frequency of said test signal comprises a frequency of 0.5 hertz.
Claim 8
Dependent Claim
43 words
The method of claim 3 wherein said power system stabilizer additionally includes an electrical transducer which generates a signal proportional to the frequency of the generator terminal voltage, and wherein said test signal is applied to the transducer for frequency modulating the transducer.
Claim 9
Dependent Claim
21 words
The method as defined by claim 6 wherein said step (a) of generating the test signal comprises generating the signal locally.
Claim 10
Dependent Claim
27 words
The method as defined by claim 7 wherein said step (a) of locally generating the test signal comprises generating the test signal within the power system stabilizer.
Claim 11
Dependent Claim
51 words
The method as defined by claim 8 wherein said step (a) of generating said test signal comprises the step of digitally generating said test signal, and additionally including the step of: (f) converting the digital test signal to an analog signal and thereafter coupling the analog test signal to said transducer.
Claim 12
Dependent Claim
39 words
The method as defined by claim 9 and wherein said step (c) of sensing and storing signals further comprises the step of converting the sensed signals into digital signals, and then storing said digital signals in a digital memory.
Claim 13
Dependent Claim
33 words
The method as defined by claim 10 and wherein said step (d) of retrieving the stored signals comprises accessing the digital memory from a remote location and then retrieving stored digital signals therefrom.
Claim 14
Dependent Claim
27 words
The method as defined by claim 11 wherein said step of accessing the digital memory includes accessing by way of a modem coupled to a telephone line.
Claim 15
Dependent Claim
35 words
The method as defined by claim 12 and additionally including the step of initiating the generating of said test signal of step (a) from said remote location by way of said modem and telephone line.
Claim 16
Dependent Claim
33 words
The method as defined by claim 10 wherein said step (d) of retrieving the stored signals comprises accessing the digital memory locally by way of the local terminal coupled to said digital memory.
Claim 17
Dependent Claim
51 words
The method as defined by claim 6 wherein said step (c) of sensing and storing comprises storing a signal corresponding to the test signal applied to said transducer, storing a signal corresponding to the output of said transducer and storing a signal corresponding to the output of the power system stabilizer.
Claim 18
Dependent Claim
43 words
The method as defined by claim 15 wherein said step (c) of sensing and storing further comprises sensing and storing said signals substantially 0.5 seconds before the insertion of the test signal and substantially 10 seconds after the insertion of the test signal.
Claim 19
Dependent Claim
24 words
The method as defined by claim 2 wherein said step (a) of generating a test signal comprises generating a step function type of signal.
Claim 20
Dependent Claim
40 words
The method as defined in claim 17 wherein the step (b) of inserting the test signal comprises coupling the test signal to the excitation system of a generator coupled to the power system stabilizer of said electrical power generating system.
Claim 21
Dependent Claim
49 words
The method as defined by claim 18 wherein said step (b) of inserting the step function type of test signal comprises inserting the test signal into the output of the power system stabilizer, said power system stabilizer thereafter coupling said test signal to the excitation system of the generator.
Claim 22
Dependent Claim
23 words
The method as defined by claim 19 and wherein said step (a) of generating a test signal comprises generating the test signal locally.
Claim 23
Dependent Claim
27 words
The method as defined by claim 19 and wherein said step (a) of generating the test signal comprises generating the test signal within the power system stabilizer.
Claim 24
Dependent Claim
54 words
The method as defined by claim 21 and wherein said step (a) of generating a test signal comprises generating a digital type of test signal and further including the step of converting the digital test signal to an analog signal, said analog signal being thereafter coupled to the output of said power system stabilizer.
Claim 25
Dependent Claim
31 words
The method as defined by claim 22 wherein said test signal comprises a step function type of signal and step (c) includes storing said digital step function type of test signal.
Claim 26
Dependent Claim
24 words
The method as defined by claim 23 wherein said step (d) of retrieving stored signals comprises accessing said digital memory from a remote location.
Claim 27
Dependent Claim
31 words
The method as defined by claim 24 wherein said step (d) of accessing said memory from a remote location comprises accessing said memory via a modem connected to a telephone line.
Claim 28
Dependent Claim
27 words
The method as defined by claim 23 wherein said step of accessing said memory comprises locally accessing said memory through a local terminal coupled to said memory.
Claim 29
Dependent Claim
55 words
The method as defined by claim 18 wherein said step (c) of sensing and storing signals comprises storing signals corresponding to: (i) generator electrical output power, (ii) generator reactive output power, (iii) at least one phase voltage of the generator terminal voltage, (iv) generator line current, (v) generator output frequency, and (vi) generator field voltage.
Claim 30
Dependent Claim
33 words
The method as defined by claim 2 and additionally including the step of: (f) initiating the test from a remote location, and comprising signal characteristics in step (c) also at said remote location.
Claim 31
Dependent Claim
41 words
The method as defined by claim 2 and additionally including the step of: (f) activating an enabling switch locally and thereafter transmitting a password from a remote location to the system for initiating said step (a) of generating the test signal.
Claim 32
Dependent Claim
137 words
Apparatus for testing an electrical power generating system, comprising: (a) at least one electrical generator including an excitation system; (b) a power system stabilizer coupled to said excitation system for damping the electromechanical oscillations of said power generating system; (c) test signal generation means included in the power system stabilizer; (d) means for activating said test signal generation means; (e) means for inserting said test signal at a predetermined point in said power generating system; (f) means for sensing selected system parameters and generating signals corresponding thereto; (g) means for storing said parameter signals; and (h) means for selectively accessing said storing means and retrieving said parameter signals therefrom, whereby said respective parameter signals can be compared before and after the insertion of the test signal for determining system performance either locally or at a remote location.
Claim 33
Dependent Claim
137 words
Apparatus for testing an electrical power generating system, comprising: (a) at least one electrical generator including an excitation system; (b) a power system stabilizer coupled to said excitation system for damping the electromechanical oscillations of said power generating system; (c) test signal generation means included in the power system stabilizer; (d) means for activating said test signal generation means; (e) means for inserting said test signal at a predetermined point in said power generating system; (f) means for sensing selected system parameters and generating signals corresponding thereto; (g) means for storing said parameter signals; and (h) means for selectively accessing said storing means and retrieving said parameter signals therefrom, whereby said respective parameter signals can be compared before and after the insertion of the test signal for determining system performance either locally or at a remote location.
Claim 34
Dependent Claim
33 words
The apparatus as defined by claim 30 wherein said test signal comprises a low frequency sinusoidal signal in the range of the natural frequency of intertie oscillatory modes of the power generating system.
Claim 35
Dependent Claim
58 words
The apparatus as defined by claim 31 wherein said power system stabilizer additionally includes an electrical transducer which generates a signal proportional to the frequency of the generator terminal output voltage, and wherein said means (e) for inserting said test signal comprises means for coupling said low frequency sinusoidal signal to said transducer for frequency modulating said transducer.
Claim 36
Dependent Claim
16 words
The apparatus as defined by claim 31 wherein said transducer comprises a continuous wave frequency transducer.
Claim 37
Dependent Claim
29 words
The apparatus as defined by claim 33 wherein said low frequency sinusoidal signal comprises a signal having a frequency in the range between and including 0.2 and 0.5 hertz.
Claim 38
Dependent Claim
18 words
The apparatus as defined by claim 30 wherein said test signal comprises a step voltage type of signal.
Claim 39
Dependent Claim
32 words
The apparatus as defined by claim 35 wherein said means (e) for inserting said test signal comprises means for coupling said voltage step signal to the excitation system of said electrical generator.
Claim 40
Dependent Claim
36 words
The apparatus as defined by claim 30 wherein said power system stabilizer comprises a digital power system stabilizer including a microprocessor, said microprocessor including a set of stored comparator programs implementing said test signal generator means.
Claim 41
Dependent Claim
45 words
The apparatus as defined by claim 37 wherein one of said stored computer programs operates to generate a 0.5 hertz sinusoidal test signal for stimulating intertie mode oscillations and another stored computer program operates to generate a step function signal for stimulating local mode oscillations.
Claim 42
Dependent Claim
24 words
The apparatus as defined by claim 38 and wherein said means for storing said parameter signals comprises a digital memory coupled to said microprocessor.
Claim 43
Dependent Claim
33 words
The apparatus as defined by claim 39 wherein said means (h) for selectively accessing said memory includes a digital communications port and additionally including a local terminal coupled to said digital communications port.
Claim 44
Dependent Claim
53 words
The apparatus as defined by claim 39 wherein said means (h) for selectively accessing said memory includes a digital communications port and additionally including a modem coupled to said digital communications port, said modem being coupled to a telephone line, whereby access to said parameter signals can be obtained at a remote location.
Claim 45
Dependent Claim
43 words
The apparatus as defined by claim 41 and additionally including a local switch means for enabling a test and means for transmitting a password from said remote location to said microprocessor for initiating the generation of at least one of said test signals.
References Cited (Backward Citations)
US4463306A
Cited
US4626622A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-04-26 | 1991-10-26 | 1992-04-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-04-26 | 1995-10-26 | 1996-04-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-04-26 | 1999-10-26 | 2000-04-26 | $7700.00 | Window Closed / Lapsed |