US5798634A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Load management and control apparatus
Assignee: Mitsubishi Electric Corp
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Filing: 1997-04-25
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Granted: 1998-08-25
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Expires: 2017-04-25
Abstract
Abstract A load management and control apparatus comprising a control unit in which system voltage and a power flow state are measured to make an arithmetic decision by using the resultant variations in voltage and reactive power so as to estimate system reactance, and the estimated system reactance is used to carry out control operation while establishing unique relationship between tap changing operation of the transformer and connection or disconnection of the reactive power supply unit in the receiving side sub-station so as to set voltage and power factor of the receiving side of power system in desired ranges, whereby in a receiving end side substation, it is possible to prevent frequent tap changing operation of the transformer, and adjust system voltage not only to reduce the voltage deviation but also to provide integrated and reasonable management of the reactive power.
Inventors
- 👤 Makoto Terada
- 👤 Isao Iyoda
- 👤 Yoshiyuki Kobayashi
- 👤 Akifumi Iwamaru
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:54
CPC Classifications
H; H02; H02J; H02J3/00; H02J3/12; H02J3/14; H02J3/18; H02J3/1878; H02J2105/00; H02J2105/50; H02J2105/51; Y; Y02; Y02B; Y02B70/00; Y02B70/30; Y02B70/3225; Y02E; Y02E40/00; Y02E40/30; Y04; Y04S; Y04S20/00; Y04S20/20; Y04S20/222
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
188 words
A load management and control apparatus installed in a receiving end substation, comprising: a transformer having a tap changer and being connected between a load bus and a source of power; a voltage adjusting unit for adjusting a tap of the transformer; a reactive power supply unit connected to said load bus; and a control unit for controlling connection or disconnection of said reactive power supply unit from said load bus and for changing said tap of said transformer, and including means for detecting active power and reactive power in addition to a detection of system voltage, means for varying the system voltage and a power flow state by the connection or disconnection of the reactive power supply unit, means for estimating system reactance by using the resultant variations in the voltage and the reactive power, and means for carrying out control operation by using the estimated system reactance and establishing a relationship between the tap changing operation of the transformer and the connection or disconnection operation of the reactive power supply unit for setting the voltage and power factor of the system receiving side within desired ranges.
Claim 2
Dependent Claim
188 words
A load management and control apparatus installed in a receiving end substation, comprising: a transformer having a tap changer and being connected between a load bus and a source of power; a voltage adjusting unit for adjusting a tap of the transformer; a reactive power supply unit connected to said load bus; and a control unit for controlling connection or disconnection of said reactive power supply unit from said load bus and for changing said tap of said transformer, and including means for detecting active power and reactive power in addition to a detection of system voltage, means for varying the system voltage and a power flow state by the connection or disconnection of the reactive power supply unit, means for estimating system reactance by using the resultant variations in the voltage and the reactive power, and means for carrying out control operation by using the estimated system reactance and establishing a relationship between the tap changing operation of the transformer and the connection or disconnection operation of the reactive power supply unit for setting the voltage and power factor of the system receiving side within desired ranges.
Claim 3
Dependent Claim
184 words
A load management and control apparatus installed in a receiving end substation, comprising: a transformer having a tap changer and being connected between a load bus and a source of power; a voltage adjusting unit for adjusting a tap of the transformer; a reactive power supply unit connected to said load bus; and a control unit for controlling connection or disconnection of said reactive power supply unit from said load bus and for changing said tap of said transformer, and including means for detecting active power and reactive power in addition to a detection of system voltage, means for monitoring and detecting variations in the active power, the reactive, and the voltage, means for estimating impedance, and to confirm variations in system properties by using the system variations means for carrying out control operation by using the estimated impedance while establishing a unique relationship between the tap changing operation of the transformer and the connection or disconnection operation of the reactive power supply unit; and means for establishing desired relationships between voltage, the active power, and the reactive power of the receiving side system.
Claim 4
Dependent Claim
184 words
A load management and control apparatus installed in a receiving end substation, comprising: a transformer having a tap changer and being connected between a load bus and a source of power; a voltage adjusting unit for adjusting a tap of the transformer; a reactive power supply unit connected to said load bus; and a control unit for controlling connection or disconnection of said reactive power supply unit from said load bus and for changing said tap of said transformer, and including means for detecting active power and reactive power in addition to a detection of system voltage, means for monitoring and detecting variations in the active power, the reactive, and the voltage, means for estimating impedance, and to confirm variations in system properties by using the system variations means for carrying out control operation by using the estimated impedance while establishing a unique relationship between the tap changing operation of the transformer and the connection or disconnection operation of the reactive power supply unit; and means for establishing desired relationships between voltage, the active power, and the reactive power of the receiving side system.
Claim 5
Dependent Claim
216 words
A load management and control apparatus installed in a receiving end substation, comprising: a transformer having a tap changer and being connected between a load bus and a source of power; a voltage adjusting unit for changing a tap of the transformer; a reactive power supply unit connected to said load bus; and a control unit for controlling connection or disconnection of said reactive power supply unit from said load bus and for changing said tap, and including means for measuring and monitoring higher harmonic voltage or current, means for using the system reactance estimated using variations in voltage and reactive power or the system impedance estimated using variations in voltage, active power and reactive power, means for carrying out control operation and establishing a relationship between the tap changing operation of the transformer and the connection or disconnection operation of the reactive power supply unit, means for setting the voltage and power factor of the system receiving side within desired ranges, means for comparing system short-circuit capacity with magnitude of a load power flow, means for automatically setting the reduction level of higher harmonics in the current system, and means for sending, externally to the apparatus, information about conditions or operation to activate an adjacent higher harmonics reducing apparatus and the reactive power supply unit.
Claim 6
Dependent Claim
216 words
A load management and control apparatus installed in a receiving end substation, comprising: a transformer having a tap changer and being connected between a load bus and a source of power; a voltage adjusting unit for changing a tap of the transformer; a reactive power supply unit connected to said load bus; and a control unit for controlling connection or disconnection of said reactive power supply unit from said load bus and for changing said tap, and including means for measuring and monitoring higher harmonic voltage or current, means for using the system reactance estimated using variations in voltage and reactive power or the system impedance estimated using variations in voltage, active power and reactive power, means for carrying out control operation and establishing a relationship between the tap changing operation of the transformer and the connection or disconnection operation of the reactive power supply unit, means for setting the voltage and power factor of the system receiving side within desired ranges, means for comparing system short-circuit capacity with magnitude of a load power flow, means for automatically setting the reduction level of higher harmonics in the current system, and means for sending, externally to the apparatus, information about conditions or operation to activate an adjacent higher harmonics reducing apparatus and the reactive power supply unit.
References Cited (Backward Citations)
JPS59136822A
Cited
US4812669A
Cited
US4752726A
Cited
US4755738A
Cited
WO1988007655A1
Cited
JPH0356035A
Cited
US5136233A
Cited
US5349522A
Cited
JPH0519873A
Cited
JPH0564373A
Cited
US5402057A
Cited
US5428551A
Cited
US5422561A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-08-24 | 2002-02-23 | 2002-08-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-08-24 | 2006-02-23 | 2006-08-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-08-24 | 2010-02-23 | 2010-08-25 | $7700.00 | Window Closed / Lapsed |