WO2007050440A2 - An apparatus and methods for providing a voltage adjustment for single-phase voltage regulator operation in a three-phase power system - Google Patents
An apparatus and methods for providing a voltage adjustment for single-phase voltage regulator operation in a three-phase power system Download PDFInfo
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- WO2007050440A2 WO2007050440A2 PCT/US2006/040965 US2006040965W WO2007050440A2 WO 2007050440 A2 WO2007050440 A2 WO 2007050440A2 US 2006040965 W US2006040965 W US 2006040965W WO 2007050440 A2 WO2007050440 A2 WO 2007050440A2
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- voltage
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Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
- G05F1/70—Regulating power factor; Regulating reactive current or power
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/18—Arrangements for adjusting, eliminating or compensating reactive power in networks
- H02J3/1878—Arrangements for adjusting, eliminating or compensating reactive power in networks using tap changing or phase shifting transformers
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/30—Reactive power compensation
Definitions
- the present invention generally relates to power system control, and more specifically, to an apparatus and methods for providing a voltage adjustment for single-phase voltage regulator operation in a three-phase power system.
- Electric utility systems or power systems are designed to generate, transmit and distribute electrical energy to loads via a variety of power system elements such as electrical generators, electrical motors, power transformers, power transmission lines, distribution lines, buses and transformers, power transmission lines, distribution lines, buses and capacitors, to name a few.
- power systems typically include a number of regulators having associated control devices, and many protective devices having associated protective .schemes to protect the power system elements from abnormal conditions such as electrical short circuits, overloads, frequency excursions, voltage fluctuations, and the like.
- protective devices and their associated protective schemes act to isolate a power system element(s) (e.g., a generator, transformers, buses, motors, etc.) from the remainder of the power system upon detection of the abnormal condition or a fault in, or related to, the power system element(s).
- a power system element(s) e.g., a generator, transformers, buses, motors, etc.
- Such protective devices may include different types of protective relays, surge protectors, arc gaps and associated circuit breakers and reclosures.
- Regulators and their associated control devices are utilized to regulate the voltage level in the power system.
- a number of single-phase step voltage regulators may be coupled to the various transmission, sub-transmission and distribution lines (collectively, “distribution lines") to enable voltage regulation of the distribution line to, for example 13kV ⁇ 10 percent, during a wide range of load conditions (e.g., a plant coming on-line).
- Such voltage regulators are often located adjacent to a step-down power transformer and generally include an autotransformer having a single winding (e.g., a series winding), which is tapped at some tap position along the winding to provide a desired voltage level.
- a typical step voltage regulator may have a 100 percent exciting winding in shunt with the distribution line on the source side, and operate to . maintain a voltage on the load side of the distribution line. The voltage is maintained within a desired voltage bandwidth by means of a 10 percent tapped buck/boost winding connected in series with the distribution line.
- the series winding has taps connected to stationary contacts of a tap changer dial switch, where the tap changer dial switch includes a pair of rotatable selector contacts driven by a reversible motor into sequential engagement with the pairs of contacts.
- the tap changer dial switch may enable a capability to change the effective turns ratio from input to output + 10 percent in 32 steps of 5/8 percent each or 0.75 V.
- a voltage control device, operatively coupled to the voltage regulator may also be included to select the proper tap position or tap for voltage regulator operation based on power system conditions.
- Voltage regulators operate via a comparison of an actual measured voltage (Ae., a secondary distribution line voltage) to some internal fixed reference voltage, or center-band voltage. A voltage difference is amplified and used to control operation of the voltage regulator via the voltage control device. Thus, if the measured voltage is too high or in a first out of band (OOB) area above an in-band area, the voltage regulator is directed by the voltage control device to execute a tap change to yield a lower voltage. If the measured voltage is too low, or in a second OOB area below the in-band area, the voltage regulator is directed by the voltage control device to execute a tap change (e.g., a one tap position change) to yield a higher voltage.
- a tap change e.g., a one tap position change
- the currents and voltages are stepped-down via current and voltage transformers, respectively.
- the three-phase current and voltages are commonly referred to as the primary current and voltages, while the stepped-down current and voltages are referred to as the secondary current and voltages, respectively.
- the stepped-down secondary current and voltages are digitized and utilized to determine corresponding phasors representative of the primary current and voltages. The phasors may then used while executing the voltage control logic scheme of the voltage control device to determine whether a tap change is required by the voltage regulator (discussed below).
- the voltage control device may cause a tap limit to be reached; that is, due to lower measured voltages over time, the voltage control device causes the voltage regulator to continue to change taps to increase the voltage delivered to the load until there are no more available taps. As a result, further decreases in the load voltage can not be addressed via a tap change.
- the problem of the tap limit may be addressed by adjusting the center-band voltage to a lower voltage via subtracting a percentage of the center-band voltage setting from the center-band voltage setting, thereby effectively lowering the reference voltage used by the voltage control device.
- a method provides a voltage adjustment for single-phase voltage regulator operation of a voltage regulator . operatively coupled to a single-phase distribution line of a three- , phase power system.
- the voltage regulator includes a plurality of taps selectable to adjust a voltage at a load of the single-phase distribution line to an in-band area.
- the method includes determining a measured voltage and a measured current based on a respective digitized voltage signal and a digitized current signal of the single-phase distribution line at the voltage regulator, and if there are no available taps and the measured voltage is in the out-of-band area above the in-band area, eliminating an effect of a line ⁇ . voltage drop between the voltage regulator and the load to adjust the. . voltage at the load.
- a method provides a voltage adjustment for single-phase voltage regulator operation of a voltage regulator operatively coupled to a single-phase distribution line of a three-phase power system.
- the voltage regulator includes a plurality of taps selectable to adjust a voltage at a load of the single-phase distribution line to an in-band area.
- the method includes determining a measured voltage and a measured current based on a respective digitized voltage signal and a digitized current signal of the single-phase distribution line at the voltage regulator, determining a line voltage drop between the voltage regulator and the load if the measured voltage is in an out-of-band area above the in-band area, and if there are no available taps, reducing an effect of the line voltage drop to adjust the voltage at the load.
- an apparatus and method provides a voltage adjustment for single-phase voltage regulator operation of a voltage regulator operatively coupled to a single-phase distribution line of a three-phase power system.
- the voltage regulator includes a plurality of taps selectable to adjust a voltage at a load of the single-phase distribution line to an in-band area.
- the apparatus includes a means for deriving a digitized voltage signal and a digitized current signal of the single-phase distribution line at the voltage regulator, and a microcontroller operatively coupled to the means for deriving.
- the microprocessor is programmed to determine a measured voltage and a measured current based on the respective digitized voltage signai and the digitized current signal, to determine a line voltage drop between the voltage regulator and the load if the measured voltage is in an out-of-band area above the in-band area, and if there are no available taps of the plurality of taps, utilize the measured voltage to adjust (lower) the voltage at the load when the measured voltage is in an out-of-band area above the in-band area. Utilization of only the measured voltage bypasses an effect of the line voltage drop on the adjustment of the voltage at the load to yield a voltage reduction for single-phase voltage regulator operation of the voltage regulator.
- an apparatus and method provides a voltage adjustment for single-phase voltage regulator operation of a voltage regulator operatively coupled to a single- phase distribution line of a three-phase power system.
- the voltage regulator includes a plurality of taps selectable to adjust a voltage at a load of the single-phase distribution line to an in-band area.
- the apparatus includes a means for deriving a digitized voltage signal and a digitized current signal of the single-phase distribution line at the voltage regulator, and a microcontroller operatively coupled to the means for deriving.
- microcontroller is programmed to determine a measured voltage and a measured current based on the respective digitized voltage and current signals, to determine a line voltage drop between the voltage regulator and the load if the measured voltage is in the out-of-band area above the in- band area, to divide the line voltage drop by a tap voltage value of a single tap of the plurality of taps to form a required taps value, and if the required taps value is greater than a number of available taps of the plurality of taps, to utilize the measured voltage less another line voltage drop to adjust the voltage at the load.
- the another line drop voltage is less than the line drop voltage and is based on the required taps value.
- the microcontroller is further programmed to divide the number of available taps by the required taps value to form a line drop compensation adjustment value, to multiply a line impedance of the single-phase distribution line by the line drop compensation adjustment value to form another line impedance, and to multiply the another line impedance by a total current of the single-phase distribution line to calculate the another line voltage drop. Utilization of the measured voltage less the another line voltage drop reduces an effect of the line voltage drop to yield the voltage reduction for single-phase voltage regulator operation of the voltage regulator. In cases where the measured voltage is in an out-of-band area below the in-band area and there are no available taps, the microcontroller is programmed to utilize the measured voltage plus a reduction voltage to adjust (further lower) the voltage at the load.
- FIGURE 1 is a single line schematic diagram of a power system that may be utilized in a typical wide area.
- FIGURE 2 is a schematic diagram illustrating a configuration of the voltage regulator with voltage control device of FIG. 1, according to an embodiment of the invention.
- FIGURE 3 is a block diagram of an exemplary configuration of the voltage control device of FIG. 2.
- FIGURE 4 is an exemplary graphic illustrating the in-band area and associated out-of-band areas that may be used by the voltage control device of FIG. 2, according to an embodiment of the invention.
- FIGURE 5 is a flowchart of a single-step line drop compensation LDC bypassing method for providing voltage reduction when reaching the tap position limit of the single-phase voltage regulator, of FIGS, land 2, . . according to an embodiment of the invention. ⁇
- FIGURE 6 is a flowchart of an incremental-step line drop compensation LDC method for providing voltage reduction before reaching the tap limit of the single-phase voltage regulator of FIGS. 1 and 2, according to an embodiment of the invention.
- Methods are provided in a voltage control device for providing voltage reduction for single-phase voltage regulator operation in a three-phase power system.
- the problem of exceeding the tap limit may be addressed by lowering the center-band voltage setting. Lowering the center-band voltage setting may result however, in an uneven system voltage profile or large system voltage changes.
- FIG. 1 is a single line schematic diagram of a power system 10 that may be utilized in a typical wide area.
- the power system 10 includes, among other things, three generators 12a, 12b and 12c, configured to generate three-phase sinusoidal waveforms such as 12 kV sinusoidal waveforms, three step-up power transformers 14a, 14b and 14c, configured to increase the generated waveforms to a higher voltage sinusoidal waveforms such as 138 kV sinusoidal waveforms and a number of circuit breakers 18.
- the step-up power transformers 14a, 14b, 14c operate to provide the higher voltage sinusoidal waveforms to a number of long distance transmission lines such as the transmission lines 20a, 20b and , 20c.
- a first substation 16 may be defined to include the , two generators 12a and 12b, the two step-up power transformers 14a and 14b and associated circuit breakers 18, all interconnected via a first bus 19.
- a second substation 35 may be defined to include the generator 12c, the step-up power transformer 14c and associated circuit breakers 18, all interconnected via a second bus 25.
- a third substation 22 includes two step-down . power transformers 24a and 24b configured to transform the higher voltage sinusoidal waveforms to lower voltage sinusoidal waveforms (e.g., 15 kV) suitable for distribution via one or more. distribution lines.
- the second substation 35 also includes two step-down power transformers 24c and 24d on respective distribution lines 28 and 29 to transform the higher voltage sinusoidal waveforms, received via the second bus 25, to lower voltage sinusoidal waveforms.
- a (line) voltage regulator 32 is included on the load side of the power transformer 24c to provide voltage regulation for the load 30, and a voltage regulator 37, identically configured and operable as the voltage regulator 32, is included on the load side -of the power transformer 24d to provide voltage regulation to the load 34.
- the voltage regulator 32 may be designed to provide 13 kV ⁇ 10% for distribution via an A-phase distribution line 28 to the load 30.
- Voltage control devices 100 and 101 are operatively coupled to respective voltage regulators 32, 37, and execute a voltage control scheme (discussed below), to provide control for their associated voltage regulators 32, 37.
- a voltage control scheme discussed below
- each of the A-, B- and C-phase distribution lines may include a single-phase voltage regulator such as the voltage regulator 32 and an associated voltage control device such as the voltage control device 100.
- FIG. 2 is a schematic diagram illustrating a configuration of the voltage regulator 32 with the voltage control device 100, according to an embodiment of the invention.
- each phase distribution line of the A-, B- and C-phase power system may include its own voltage regulator and voltage control device.
- the voltage regulator 32 and the voltage control device 100 are operatively coupled to an A-phase distribution line 28.
- the voltage control device 100 is designed to utilize currents and voltages much less than those of a distribution line such as, for example, the A-phase distribution line 28, transformers are provided.
- the voltage control device 100 is coupled to the A-phase distribution line 28 via one current transformer 36 and one voltage transformer 40.
- the voltage transformer 40 is used to step-down the power system voltage to a secondary voltage waveform V 54 46 having a magnitude that can be readily monitored and
- the voltage control device 100 e.g., to step-down the distribution line voltage from 13kV to 120 V.
- the current transformer 36 is utilized to proportionally step-down the power system line current to a secondary current / ⁇ 44 having a magnitude that can be readily
- a second voltage transformer 38 may also be included for use during a reverse load condition (i.e., a generator is switched in on the load side).
- each of the current transformer 36 and the voltage transformer(s) 40 are included in the voltage regulator 32, however other arrangements of the voltage regulator 32, the voltage control device 100 and associated transformers are contemplated.
- the A-phase . . secondary current and A-phase-to-ground voltage are filtered, processed and utilized by a microcontroller 130 to calculate phasors having corresponding magnitudes and phase angles.
- FIG. 3 is a block diagram of an exemplary configuration of the voltage control device 100. During operation of the voltage control device 100, the secondary current waveform I ⁇ 44
- transformer 40 is similarly processed and filtered via another analog low pass filter 116.
- An analog-to-digital (AJO) converter 120 then multiplexes, samples and digitizes the filtered secondary current and secondary voltage . waveforms to form a corresponding digitized current and voltage signal 124.
- the corresponding digitized current and voltage signal 124 is received by a microcontroller 130, where it is digitally filtered via, for example, Cosine filters to eliminate DC and unwanted frequency components.
- the microcontroller 130 includes a CPU, or a microprocessor 132, a program memory 134 (e.g., a Flash EPROM) and a parameter memory 136 (e.g., an EEPROM).
- a program memory 134 e.g., a Flash EPROM
- a parameter memory 136 e.g., an EEPROM
- other suitable microcontroller configurations or FPGA configurations
- FPGA configurations may be utilized.
- the embodiments presented and claimed herein may be practiced using an FPGA or other equivalent.
- the microprocessor 132 executing a computer program or voltage control logic scheme (discussed below in connection to Figure 4), processes (each of) the digitized current and voltage signal 124 to extract phasors representative of a corresponding measured secondary voltage F ⁇ and
- the microprocessor 132 issues a tap change command to the voltage regulator 32 to cause a tap change (i.e., change the effective turns ratio) to adjust the A-phase-to-ground voltage to the desired center-band voltage, or reference voltage.
- a tap change i.e., change the effective turns ratio
- voltage regulators generally operate via a comparison of an actual measured secondary voltage V 34 to some internal
- FIG. 4 is an exemplary graphic 150 illustrating the in-band area 152, including the center-band voltage 153, and associated OOB areas 154, 156 that may be used by the voltage control device of 100, according to an embodiment of the invention. Although assigned voltage values for discussion purposes, it should be noted that the in-band area 152 and the first and second OOB areas 154, 156 may include different voltage values.
- a center-band voltage 153 included within an in-band area 152 is selected to be 120 V ⁇ 2V for a total in-band area width of 4 V.
- the first OOB area 154 begins at a first in-band/OOB edge 155 at 122V and extends upward beyond 128V, where 128V is the maximum voltage above which tap RAISE commands are suspended by the voltage control device 100.
- the second OOB area 156 begins at a second in- band/OOB edge 157 at 118V and extends downward beyond 109V, where 109V is the minimum voltage below which tap LOWER commands are suspended by the voltage control device 100.
- a deadband area 158 is .
- the voltage control device 100 issues a tap LOWER command without any time delay.
- the distribution lines 28 and 29 of the second substation 35 may not draw the same current due to their respective different loads 30 and 34, regulating the measured voltage at the second substation 35 may result in undesirable- high voltages on lightly- loaded distribution lines and undesirable low voltage on heavily loaded distribution lines.
- the problem of undesirable high and low voltages on distribution lines due to load variations may be addressed via compensating for the voltage drop across, for example, the A-phase distribution line 28 between the voltage regulator 32 and the load 30.
- the voltage control device 100 determines tap changes based on a calculated controller voltage V CONTROLLER that includes distribution line voltage drops, or line voltage .
- the voltage control device 100 via the voltage regulator 32 regulates the overall system, or load voltage to a level that is higher than the reference voltage of the in- band area 152.
- the voltage control device 100 determines a tap change based on the controller voltage V C0NTR0LLER that includes the line voltage drop 39 reflected as
- the microcontroller 130 utilizes a controller voltage V CONTROLLER of 119 V to
- the controller voltage V CONTROLLER of 119 V reflects the measured voltage 46 of
- V CONTROLLER v MEAS U RED - V L i NEDR ⁇ p
- the microcontroller 130 uses the principles discussed above and based on the controller voltage V comROLLER of 119 V to cause a tap change
- load current As a current of the load 30 ("load current") increases due to, for example, additional power needs, the load voltage 43 generally decreases. : The decreased load voltage 43 results in a decreased measured voltage sample V MEASURED at the voltage regulator 32. As a result, the controller
- V CONTROLLER is Iower tnan tne center-band voltage 153, a tap change occurs to
- FIG. 5 is a single-step line drop compensation (LDC) bypassing method 200 for providing load voltage reduction when reaching the tap limit of the single- phase voltage regulator 32, according to an embodiment of the invention.
- LDC line drop compensation
- load voltage 43 may be defined to include a voltage at the load 30 defined by the distribution line parameters R+jX.
- the single-step LDC bypassing method 200 includes removing or bypassing the affects of the distribution line parameters R+jX
- the single-step LDC bypassing method 200 begins when the microcontroller 130 determines a measured voltage V MEASURED and a measured current I MEASURED (derived from I ⁇ 44) at
- step 202 determines a line voltage drop V LINEDROP , or the voltage drop across the distribution line 28 between the
- the measured voltage ⁇ MEASURED at tne voltage regulator 32 is based on a digitized voltage signal
- the line voltage drop V L1NEDR0P may be affected by a
- the line is characterized by the distribution line parameters R+jX .
- V L!NEDROP may be calculated using the total current I T0TAL and
- V LINEDR0P I TOTAL *Z ⁇ mE .
- calculation of the total current I T0TAL is based on the
- the microcontroller 130 can determine the line voltage drop V umDR0P
- phase current transformer 36 may be used rather than calculating the total current I T0TAL (the total current I T0TAL requiring V MEASURED , and the sum of
- the line voltage drop is equal to a product of the line impedance and the measured current I MEASURED , where the measured current I MEASURED is
- the microcontroller 130 uses the controller voltage V CONTROLLER to determine a tap change, where the controller
- V CONTROLLER includes the line voltage drop V mEmoP (step 206), or
- VCONTROLLER v mAsuRED - ⁇ UNEDROP • l n other words - the measured voltage
- microcontroller 130 uses an adjusted controller voltage V CONTROLLER _ ADJUST to calculate the controller voltage V CONTROLLER _ ADJUST to calculate the controller voltage V CONTROLLER _ ADJUST.
- the adjusted controller voltage does not include the line voltage drop V mEDROP . In that case
- FIG. 6 is an incremental-step line drop compensation (LDC) method 300 for providing incremental load voltage reduction before reaching the tap limit of the single-phase voltage regulator 32, according to an embodiment of the invention.
- LDC line drop compensation
- the incremental-step LDC method 300 provides a smoother system voltage profile during OOB conditions 154 above the in- band area 152 due to incremental load voltage decrease .
- the incremental-step LDC method 300 is equally applicable to any regulated load voltage.
- the incremental-step LDC method 300 includes incrementally reducing the. affects of the distribution line parameters i2,+. jX
- V LINEDR0P voltage drop
- the microcontroller 130 may be initiated when the microcontroller 130 detects that a predetermined threshold has been exceeded. For example, the incremental reduction may begin when the microcontroller 130 detects that a required taps value exceeds the number of available taps Taps AVAILABLE .
- the incremental-step LDC method 300 begins when the microcontroller 130 determines a measured voltage V MEASURED and a measured current I MEAS ⁇ RED at the voltage regulator
- the microcontroller 130 determines a line voltage drop V mEDR0P , or the voltage drop across the
- the line voltage drop V UNEDR0P may be calculated as described above
- microcontroller 130 determines how many taps are represented by the magnitude of the calculated line voltage drop V mEDR0P via dividing
- the microcontroller 130 compares the required taps value
- required taps value is less than or equal to the number of available taps
- Taps AVA1LABLE ' tne microcontroller 130 regulates, in this case lowers, the load voltage 43 using the controller voltage equal to the measured voltage
- V CON TROLLER ⁇ ME AS URED ⁇ V L 1 NE D ROP ' ⁇ *» r ⁇ SUlt, tK ⁇ full ⁇ ff ⁇ Ct Of tll ⁇ distribution
- line parameters R+jX is included in the determination of a tap change to
- the microcontroller 130 calculates an LDC adjustment
- the LDC adjustment value is a value less than one, and is
- microcontroller 130 multiplies the line impedance Z L1NE by the LDC
- V ummop _ mw V ummop _ mw
- the microcontroller 130 then regulates the load voltage 43 using an adjusted controller voltage V CONTROLLER _ ADJUST equal to the measured voltage
- the microcontroller 130 regulates the load voltage 43 using an adjusted controller voltage that includes an adjusted line voltage loss reflected as a portion of the distribution line parameters R+jX such that
- V CONTROUER_ADJVST ⁇ MEASURED] ⁇ ⁇ Ll NED RO P _N E W
- adjusted controller voltages to incrementally remove the effects of the distribution line parameters from the calculation to regulate the load voltage 43 may continue until either the load voltage 43 is in the in-band area 152 (step 317) or until the tap limit has been reached. In this way, the affect of the distribution line parameters R+jX on the controller voltage is
- the microcontroller 130 includes the
- the LDC adjustment value is equal to 1.
- the microcontroller 130 uses a new adjusted voltage of 115.175 V to regulate the load voltage 43, via a six tap change, to the in-band area 152.
- LDC _ Adjust 3 tap % ta s ⁇
- the microcontroller 130 multiplies line impedance Z LINE of 5Z60 0 by the
- V LINEDRQP _ NEW equal to 2.412Z28.85 0 .
- the microcontroller 130 uses a new adjusted voltage of 117.59 V to regulate the load voltage 43, via a tap change, to the in-band area 152.
- the microcontroller 130 uses a new adjusted voltage of 117.59 V to regulate the load voltage 43, via a tap change, to the in-band area 152.
- the effect of the distribution line parameters on the load voltage regulation decreases, thereby increasing the new adjusted voltage incrementally to the in-band area 152, and decreasing the system or load voltage.
- the center-band voltage 153 may not provide the needed load voltage 43 decrease. Accordingly, voltage reduction via lowering the center-band voltage 153 may additionally be used after executing either of the single- step LDC bypassing method or the incremental-step LDC method 300 described above.
- step 1 may include bypassing the distribution line parameters R+jX to provide only the voltage measured V MEASURED for
- step 2 may include lowering the center- band voltage 153 by 2 %; and step 3 may include again lowering the center- band voltage 153 by 2 %, and so on until the load voltage 43 is regulated to the center-band voltage 153.
- step 3 may include again lowering the center- band voltage 153 by 2 %, and so on until the load voltage 43 is regulated to the center-band voltage 153.
- ⁇ . . . ⁇ O58 As noted above, one prior art method of adjusting the load voltage 43 includes simply lowering or raising the center-band voltage 153, depending on tap availability and the measured voltage V MEASURED . According to an
- the system voltage reduction method can also be used
- V ssm ⁇ m ⁇ is preferably expressed as a percentage of the center-band
- voltage 153 setting (e.g., 2 % of a 120V center-band voltage setting), and may be either fixed or variable, depending on the controller design.
- V UD ⁇ caar to and therefore a lower load or system voltage 43. Accordingly, multiple adjustments via V ⁇ crmr yields incremental decreases in the load voltage
- the voltage control device 100 causes the voltage regulator 32 to "tap down" such that the measured voltage V MEASURED
- V ⁇ DUC ⁇ W term causes the voltage control device 100 to assume a higher .
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
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CA2624411A CA2624411C (en) | 2005-10-21 | 2006-10-18 | An apparatus and methods for providing a voltage adjustment for single-phase voltage regulator operation in a three-phase power system |
BRPI0617615-1A BRPI0617615A2 (en) | 2005-10-21 | 2006-10-18 | apparatus and method for providing a voltage adjustment for single-phase voltage regulator operation of a voltage regulator, and method for providing a voltage reduction for single-phase voltage regulator operation of a voltage regulator |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
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US72934105P | 2005-10-21 | 2005-10-21 | |
US60/729,341 | 2005-10-21 | ||
US11/368,827 US7271572B2 (en) | 2005-10-24 | 2006-03-06 | Apparatus and methods for providing a voltage adjustment for single-phase voltage regulator operation in a three-phase power system |
US11/368,827 | 2006-03-06 |
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WO2007050440A2 true WO2007050440A2 (en) | 2007-05-03 |
WO2007050440A3 WO2007050440A3 (en) | 2009-05-14 |
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PCT/US2006/040965 WO2007050440A2 (en) | 2005-10-21 | 2006-10-18 | An apparatus and methods for providing a voltage adjustment for single-phase voltage regulator operation in a three-phase power system |
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CA (1) | CA2624411C (en) |
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Citations (4)
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US5581173A (en) * | 1991-01-03 | 1996-12-03 | Beckwith Electric Co., Inc. | Microcontroller-based tap changer controller employing half-wave digitization of A.C. signals |
GB2339928A (en) * | 1996-12-05 | 2000-02-09 | Robert Wallace Beckwith | Controlling VAR flow in electrical power systems |
US6118676A (en) * | 1998-11-06 | 2000-09-12 | Soft Switching Technologies Corp. | Dynamic voltage sag correction |
US6486644B1 (en) * | 1999-05-28 | 2002-11-26 | Arris International, Inc. | Method and architecture for limiting input current to a broadband network power supply |
-
2006
- 2006-10-18 WO PCT/US2006/040965 patent/WO2007050440A2/en active Application Filing
- 2006-10-18 CA CA2624411A patent/CA2624411C/en not_active Expired - Fee Related
- 2006-10-18 BR BRPI0617615-1A patent/BRPI0617615A2/en not_active IP Right Cessation
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5581173A (en) * | 1991-01-03 | 1996-12-03 | Beckwith Electric Co., Inc. | Microcontroller-based tap changer controller employing half-wave digitization of A.C. signals |
GB2339928A (en) * | 1996-12-05 | 2000-02-09 | Robert Wallace Beckwith | Controlling VAR flow in electrical power systems |
US6118676A (en) * | 1998-11-06 | 2000-09-12 | Soft Switching Technologies Corp. | Dynamic voltage sag correction |
US6486644B1 (en) * | 1999-05-28 | 2002-11-26 | Arris International, Inc. | Method and architecture for limiting input current to a broadband network power supply |
Also Published As
Publication number | Publication date |
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WO2007050440A3 (en) | 2009-05-14 |
CA2624411C (en) | 2011-12-13 |
CA2624411A1 (en) | 2007-05-03 |
BRPI0617615A2 (en) | 2011-08-02 |
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