US6858953B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
Power control interface between a wind farm and a power transmission system
Assignee: Hawaiian Electric Co Inc
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Filing: 2003-10-17
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Granted: 2005-02-22
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Expires: 2023-10-17
Abstract
Abstract A power control interface between an unstable power source such as a wind farm and a power transmission line employs an electrical energy storage, control system, and electronic compensation module which act together like an “electronic shock absorber” for storing excess power during periods of increased power generation and releasing stored energy during periods of decreased power generation due to wind fluctuations. The control system is provided with a “look ahead” capability for predicting power output (wind speed conditions) and maintaining energy storage or release over a “narrow-band” range despite short duration fluctuations. The control system uses data derived from monitoring the wind farm power output and the power transmission line, and employs system-modeling algorithms to predict narrow-band wind speed conditions. The power control interface can also use its energy storage capacity to provide voltage support at the point of injection into the power transmission system, as well as fault clearance capability for “riding out” transient fault conditions occurring on the power transmission line.
Inventors
- 👤 Karl E. Stahlkopf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 03:11
CPC Classifications
H; H02; H02J; H02J3/00; H02J3/28; H02J3/32; F; F03; F03D; F03D17/00; F03D9/00; F03D9/10; F03D9/11; F03D9/20; F03D9/25; F03D9/255; F03D9/257; H02J3/38; H02J3/381; H02P; H02P9/00; H02P9/04; F05; F05B; F05B2260/00; F05B2260/96; F05B2270/00; F05B2270/40; F05B2270/404; H02J2101/00; H02J2101/20; H02J2101/28; H02J3/46; H02J3/50; Y; Y02; Y02A; Y02A30/00; Y02E; Y02E10/00; Y02E10/70; Y02E10/72; Y02E10/76; Y02E70/00; Y02E70/30; Y02P; Y02P90/00; Y02P90/50
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
254 words
A power control interface between a power output of an unstable power source such as a wind farm and a power transmission line, comprising: (a) an electrical energy storage coupled between the unstable power source and the power transmission line to store excess power output when it is above a normal output level of the unstable power source and to release stored electrical energy to add to the power output when it is below the normal output level of the unstable power source; (b) a control system which receives a power source data signal derived from monitoring the power output of the unstable power source and a transmission line data signal derived from monitoring the power transmission line, and which determines when electrical energy stored in the electrical energy storage is to be released to add to power output to the power transmission line to compensate for conditions of decreased power generation encountered by the unstable power source, or when excess electrical energy generated during conditions of increased power generation encountered by the unstable power source is to be stored in the electrical energy storage; and (c) an electronic compensation module which receives a control signal from the control system corresponding to its determination and operates to release electrical energy stored in the electrical energy storage to add to power output to the power transmission line to compensate for decreased power source output, and to store excess electrical energy from increased power source output in the electrical energy storage in accordance with said determination.
Claim 2
Dependent Claim
254 words
A power control interface between a power output of an unstable power source such as a wind farm and a power transmission line, comprising: (a) an electrical energy storage coupled between the unstable power source and the power transmission line to store excess power output when it is above a normal output level of the unstable power source and to release stored electrical energy to add to the power output when it is below the normal output level of the unstable power source; (b) a control system which receives a power source data signal derived from monitoring the power output of the unstable power source and a transmission line data signal derived from monitoring the power transmission line, and which determines when electrical energy stored in the electrical energy storage is to be released to add to power output to the power transmission line to compensate for conditions of decreased power generation encountered by the unstable power source, or when excess electrical energy generated during conditions of increased power generation encountered by the unstable power source is to be stored in the electrical energy storage; and (c) an electronic compensation module which receives a control signal from the control system corresponding to its determination and operates to release electrical energy stored in the electrical energy storage to add to power output to the power transmission line to compensate for decreased power source output, and to store excess electrical energy from increased power source output in the electrical energy storage in accordance with said determination.
Claim 3
Dependent Claim
46 words
A power control interface according to claim 1 , wherein the power source is a wind farm providing an AC power output, and the power output is stored in a selected one of the group of electrical energy storage devices consisting of ultracapacitors, capacitors, and batteries.
Claim 4
Dependent Claim
46 words
A power control interface according to claim 1 , wherein the power source is a wind farm providing an AC power output, and the AC power output is converted by an ac-to-dc inverter to direct current (DC) for storage in a DC capacitor array or battery.
Claim 5
Dependent Claim
75 words
A power control interface according to claim 1 , wherein the control system includes a power source monitoring means, a transmission line monitoring means, and a control calculating means for calculating what the power output of the unstable power source is likely to be over a narrow-band range and for maintaining the release of energy or the storage of energy in the electrical energy storage over the narrow-band range despite power fluctuations of short duration.
Claim 6
Dependent Claim
58 words
A power control interface according to claim 4 , wherein the power source is a wind farm, and the control system receives data signals derived from monitoring the power output of the wind farm, and data signals derived from monitoring conditions on the transmission line, and the control system employs system-modeling algorithms to predict narrow-band wind speed conditions.
Claim 7
Dependent Claim
31 words
A power control interface according to claim 5 , wherein the control system's algorithms include prediction based on current data on wind farm output and historical data of wind farm output.
Claim 8
Dependent Claim
47 words
A power control interface according to claim 1 , wherein the electrical energy storage includes an energy storage circuit, a charge controller at an input side of the energy storage circuit, and a discharge controller at an output side of the energy storage circuit for energy release.
Claim 9
Dependent Claim
29 words
A power control interface according to claim 7 , wherein the charge controller and the discharge controller act like double-action gates controlled by signals from the electronic compensation module.
Claim 10
Dependent Claim
46 words
A power control interface according to claim 7 , wherein the power source is a wind farm providing an AC power output, and the power output is stored in a selected one of the group of electrical energy storage devices consisting of ultracapacitors, capacitors, and batteries.
Claim 11
Dependent Claim
27 words
A power control interface according to claim 9 , wherein the electrical energy storage is an array of ultracapacitors arranged to store electrical energy in respective stages.
Claim 12
Dependent Claim
41 words
A power control interface according to claim 1 , further comprising power electronics circuitry for providing voltage support at the point of connection of the wind farm with the power transmission line by using energy stored in said electrical energy storage.
Claim 13
Dependent Claim
24 words
A power control interface according to claim 11 , wherein the power electronics circuitry for providing voltage support is distribution static compensator (D-STATCOM) circuitry.
Claim 14
Dependent Claim
41 words
A power control interface according to claim 1 , wherein the control system includes a control mode for fault clearance capability for “riding through” a fault condition on the power transmission line by using energy stored in said electrical energy storage.
Claim 15
Dependent Claim
47 words
A power control interface according to claim 13 , wherein the control system receives data signals derived from monitoring the transmission line, and enables the electrical energy storage to release stored energy to maintain power output when a fault condition on the power transmission line is detected.
Claim 16
Independent Claim
178 words
A method of interfacing a power output of an unstable power source such as a wind farm with a power transmission line, comprising: (a) coupling an electrical energy storage between the unstable power source and the power transmission line to store excess power output when it is above a normal output level of the unstable power source and to release stored electrical energy to add to the power output when it is below the normal output level of the unstable power source; (b) controlling the electrical energy storage to act with a “shock-absorber” function based on monitoring the power output of the unstable power source and conditions on the power transmission line, by determining when electrical energy stored in the electrical energy storage is to be released to add to power output to the power transmission line to compensate for conditions of decreased power generation encountered by the unstable power source, and when excess electrical energy generated during conditions of increased power generation encountered by the unstable power source is to be stored in the electrical energy storage.
Claim 17
Independent Claim
178 words
A method of interfacing a power output of an unstable power source such as a wind farm with a power transmission line, comprising: (a) coupling an electrical energy storage between the unstable power source and the power transmission line to store excess power output when it is above a normal output level of the unstable power source and to release stored electrical energy to add to the power output when it is below the normal output level of the unstable power source; (b) controlling the electrical energy storage to act with a “shock-absorber” function based on monitoring the power output of the unstable power source and conditions on the power transmission line, by determining when electrical energy stored in the electrical energy storage is to be released to add to power output to the power transmission line to compensate for conditions of decreased power generation encountered by the unstable power source, and when excess electrical energy generated during conditions of increased power generation encountered by the unstable power source is to be stored in the electrical energy storage.
Claim 18
Dependent Claim
63 words
A method of interfacing a power output of an unstable power source according to claim 15 , further comprising calculating what the power output of the unstable power source is likely to be over a narrow-band range, and maintaining the release of energy or the storage of energy in the electrical energy storage over the narrow-band range despite power fluctuations of short duration.
Claim 19
Dependent Claim
64 words
A method of interfacing a power output of an unstable power source according to claim 16 , wherein the power source is a wind farm, and calculating the likely power output of the wind farm is based on monitoring current power output of the wind farm and using historical wind farm data, and employing system-modeling algorithms to predict narrow-band wind farm output based therein.
Claim 20
Dependent Claim
68 words
A method of interfacing a power output of an unstable power source according to claim 15 , wherein the electrical energy storage includes an energy storage circuit, a charge controller at an input side of the energy storage circuit, and a discharge controller at an output side of the energy storage circuit for energy release, and wherein the charge controller and the discharge controller act like double-action gates.
Claim 21
Dependent Claim
43 words
A method of interfacing a power output of an unstable power source according to claim 15 , further comprising providing for voltage support at the point of power injection with the power transmission line by using energy stored in the electrical energy storage.
Claim 22
Dependent Claim
44 words
A method of interfacing a power output of an unstable power source according to claim 15 , further comprising providing for fault clearance capability for “riding through” a fault condition on the power transmission line by using energy stored in the electrical energy storage.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2008-02-22 | 2008-08-23 | 2009-02-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2012-02-22 | 2012-08-23 | 2013-02-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2016-02-22 | 2016-08-23 | 2017-02-22 | $7700.00 | Window Closed / Lapsed |