WO1992016302A1 - Reacteur limiteur de courant electriquement variable pour appareils de precipitation - Google Patents

Reacteur limiteur de courant electriquement variable pour appareils de precipitation Download PDF

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Publication number
WO1992016302A1
WO1992016302A1 PCT/US1991/001745 US9101745W WO9216302A1 WO 1992016302 A1 WO1992016302 A1 WO 1992016302A1 US 9101745 W US9101745 W US 9101745W WO 9216302 A1 WO9216302 A1 WO 9216302A1
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WO
WIPO (PCT)
Prior art keywords
clr
control
current limiting
limiting reactor
transformer
Prior art date
Application number
PCT/US1991/001745
Other languages
English (en)
Inventor
David Johnston
Peter Birscak
Original Assignee
Hitran Corporation
Bha Group, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitran Corporation, Bha Group, Inc. filed Critical Hitran Corporation
Priority to PCT/US1991/001745 priority Critical patent/WO1992016302A1/fr
Priority to DE69127815T priority patent/DE69127815D1/de
Priority to EP91906521A priority patent/EP0528805B1/fr
Priority to CA002082056A priority patent/CA2082056C/fr
Publication of WO1992016302A1 publication Critical patent/WO1992016302A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00—Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/34—Constructional details or accessories or operation thereof
    • B03C3/66—Applications of electricity supply techniques
    • B03C3/68—Control systems therefor

Definitions

  • An electrostatic precipitator is an air pollution control device designated to electrically charge and collect particulates generated from industrial
  • Particulate-laden gas flows through the precipitator where the particles acquire a charge. These charged particles are attracted to, and collected by, oppositely-charged metal plates. The cleaned process gas may then be further processed or safely discharged to the atmosphere.
  • a precipitator should operate at the highest practical usable energy level, increasing both the particle charge and collection capabilities of the system. At the same time, there is an energy level above which arcing or
  • sparking a temporary short which creates a conductive gas path, occurs in the system. Maximizing the efficiency of an electrostatic precipitator requires operating the system at the highest possible usable energy level.
  • the electrostatic precipitator should operate constantly at its point of greatest efficiency.
  • conditions under which an electrostatic precipitator operates such as temperature, combustion rate, and the chemical composition of the particles being collected, change constantly. This complicates
  • This invention relates to electrostatic precipitators in general and specifically to precipitator power supplies.
  • Prior art precipitator power supplies have used either saturable core reactors or silicon-controlled rectifiers (SCRs) paired with a fixed-value current-limiting reactor (CLR).
  • SCRs silicon-controlled rectifiers
  • CLR fixed-value current-limiting reactor
  • Prior art CLRs have an inductance of fixed value with several taps for selecting other values. The number of taps available is limited, typically to three. Adjusting the inductance of the CLR requires that the precipitator field section be powered down and taps manually changed.
  • a CLR of the correct value contributes to protecting the precipitator power supply from the
  • Patent No. 4,973,930 issued November 27, 1990 to U. Mai et al on a Twin Coil.
  • saturable core reactor An alternative to the silicon-controlled rectifiers paired with a fixed-value current limiting reactor is a saturable core reactor.
  • the saturable core reactor (or saturable reactor) was originally developed in Germany and was used in the United States extensively from 1945 foreward. The principal application has been to control the power applied to heating elements. Saturable reactors are electrically and mechanically rugged. In recent years, their functions have been largely taken over by silicon-controlled rectifiers; as a consequence, the saturable reactor has been relegated to obscurity.
  • the present invention generally provides a current limiting reactor for use within a power supply system for a electrostatic precipitator wherein the inductance of the current limiting reactor can be
  • variable current limiting reactor of the present invention be constructed such as to
  • the basic precipitator power supply includes a silicon controlled rectifier stack which preferably includes two individual silicon control rectifiers
  • An automatic control can be operative to modify the output of the silicon control rectifier stack to modify the power output of the silicon controlled rectifier stack.
  • the silicon controlled rectifier stack output When operated at maximum power the silicon controlled rectifier stack output includes a sinusoidal AC current waveform. However when operated below the rating thereof there is a naturally occurring deterioration of the waveform in addition to the power output.
  • the current limiting reactor is positioned in series with respect to the silicon controlled rectifier stack. In prior art configurations this current limiting reactor was of a fixed inductance value or had various taps to allow some element of modification of the
  • this current limiting reactor is dynamic and continuously responsive to system parameters in order to vary the inductance thereof.
  • the operative current limiting reactor is connected to a transformer rectifier set. Initially the primary of the transformer receives the low voltage and high current signal and transforms this to a high voltage and low current signal in the secondary of the
  • the output of the step-up transformer secondary is provided to a rectifier which provides a high voltage DC signal to the precipitator to facilitate collection of particulate matter.
  • control winding is connected to a variable DC power source.
  • This control winding is adapted to vary the inductance of the current limiting reactor responsive to variations in the DC power source.
  • electrical coupling between the control winding and the inductor winding or windings of the current limiting reactor is achieved through a magnetic core.
  • two identical inductor windings are wound about a magnetic core.
  • the core extending through each inductor winding extends through the control winding in opposite directions to yield a resultant instantaneous flux through the control winding of zero.
  • the inductance of the CLR control device is a function of the magnitude of the DC current passing through the control winding.
  • Operation of the control winding can be automatic responsive to sensed system conditions such as the dynamic variables within the precipitator field.
  • Preferably variation in DC power supply to the control winding is responsive to the shape of the AC waveform at the input of the primary of the transformer rectifier set or is responsive to the shape of the
  • the present invention can include a somewhat modified automatic system for controlling the inductance of the current limiting reactor wherein a current transformer utilizes the primary current passing in series from the silicon controlled rectifier to the transformer rectifier set as the primary with a transformer secondary winding extending thereabout.
  • the output signal of the current transformer secondary winding is rectified by a conventional full wave bridge rectifier and is provided to the control winding of the current limiting reactor control winding. The DC current through this control winding will then modify the
  • inductance value of the inductor winding of the current limiting reactor will be proportionally responsive to the current at the primary of the transformer rectifier set.
  • electrostatic precipitator wherein a high secondary fractional conduction at any power level is achieved at the output of the full wave rectifier of the transformer rectifier set.
  • electrostatic precipitator wherein the destructive effects of arcing or spark currents are minimized.
  • electrostatic precipitator wherein greater electrical and particulate collection efficiencies are achieved.
  • electrostatic precipitator wherein the overall average voltage and current in the precipitator field is increased before spark over occurs thereby permitting a higher overall power level before spark over.
  • Figure 1 is a schematic illustration of a typical precipitator power system
  • Figure 2 is a graph of a conventional sinusoidal waveform
  • Figure 3 is a vector diagram for determining the impedance of the current limiting reactor
  • Figure 4 is a graph of kilovolts vs. milliamps showing the advantages of the variable current limiting reactor over the prior art fixed current limiting reactor;
  • Figure 5 is a schematic of an embodiment of an automatic electrically variable current limiting reactor
  • Figure 6 is a schematic illustration of an embodiment of the general coil and core configuration for an electrically variable current limiting reactor
  • Figure 7 is a perspective illustration of an embodiment of the electrically variable current limiting reactor shown in Figure 6;
  • Figure 8 is a perspective illustration of an embodiment of the general coil and core configuration for an electrically variable current limiting reactor.
  • Figure 9 is a graph of a transfer function of an electrically variable current limiting reactor.
  • the present invention is designed to provide a precipitator field 10 where particulate matter is actually collected. It is made up of collecting plates connected to one side of the precipitator power supply. The other side of the supply is connected to discharge electrodes 58 which are uniformly spaced from the collection plates.
  • the field in effect, forms a capacitor, two conductors separated by an insulating material.
  • the precipitator power supply is operated at a very high direct-current voltage which charges particulates entering the field as well as causing them to be attracted to the collecting plates. As the voltage of the precipitator power supply is increased, particulate collection increases. The voltage cannot be increased infinitely, however; the practical high-voltage ceiling is limited by the
  • Ionized gas is a
  • transformer-rectifier (TR) set 22 If the precipitator power supply is not interrupted when a spark occurs, the spark may be maintained, causing current flow in the precipitator to become very high as energy is gained from the power supply. Spark currents are wasted energy; they do not contribute to the collection of particulates.
  • a transformer rectifier (TR) set 22 is a combination step-up transformer and full-wave rectifier.
  • the transformer transforms the primary voltage to a very high secondary voltage and transforms the primary current to a low secondary current.
  • the rectifier converts the alternating current (AC) output from the secondary of the transformer to full-wave rectified DC.
  • a typical TR set used in a precipitator application is filled with oil for cooling and insulation. Typical ratings might be:
  • one TR set is connected to one or two precipitator field sections.
  • SCR silicon-controlled rectifiers 16 and 18
  • An SCR is a solid-state device that acts like a switch because it has a "gate" that allows it to be turned on electrically.
  • a first silicon-controlled rectifier 16 and a second silicon-controlled rectifier 18 are connected in an inverse-parallel configuration in series between the line voltage power source 14 and ahead of the current-limiting reactor 24 and the precipitator high voltage transformer. Each SCR conducts alternately, one on the positive half- cycle, the other on the negative half-cycle.
  • Some form of automatic SCR voltage control 20 typically
  • microprocessor-based determines which SCR is switched on and at what point in the half-cycle of the waveform. An SCR which is switched on remains on until the current flowing through it decays below what is called the
  • a complete sine (sinusoidal) wave cycle 28, one positive followed by one negative half-cycle, is measured in its progress by degrees from zero to 360 ( Figure 2).
  • a half-cycle is measured in its progress from zero to 180 degrees. The point at which an SCR is turned on, or
  • firing is measured in degrees from the beginning of the half-cycle and hence is called the firing angle.
  • the part of the half-cycle during which the SCR conducts is also measured in degrees from the firing point until conduction ceases and is called the conduction angle.
  • Power control is achieved with SCRs by varying the point in the half- cycle at which each SCR is switched on. The nature of the SCR device is such that the output from the stack is no longer a sine wave 28 because each half-cycle is "chopped" at the point in that cycle where an SCR is "fired” or switched into a conductive state.
  • Determining the SCR stack rating also involves several considerations.
  • the SCRs 16 and 18 must each have a current rating that exceeds that of the TR set 22 with which they will be used.
  • the blocking voltage of each SCR must be approximately three times the line voltage to prevent inadvertent conduction of the SCR resulting from voltage breakdown.
  • the rate of change of voltage with respect to time (expressed as dv/dt) must also be
  • the SCR automatic voltage control measures the primary and secondary voltages and currents (some also monitor form factor and secondary fractional conduction), and is connected to the SCR stack 12.
  • the AVC provides the triggering pulses which fire the SCRs, putting them into a state of conduction. It determines where in the electrical half-cycle to fire a particular SCR, thereby achieving power control. For example, if the AVC fired each SCR 16 or 18 at 90 degrees into the electrical half-cycle, the firing angle would be 90 degrees, the
  • the conduction angle would be 90 degrees, and exactly half of the AC power would be applied to the TR set 22. It is in this manner that the AVC 20 provides power control to ensure operation within the electrical limits of the equipment. Further, if the AVC does not fire an SCR for a half-cycle, then the output of the precipitator power supply is interrupted for that half-cycle. This permits interrupting or "quenching" sparks when the AVC detects them.
  • the current-limiting reactor 24 (CLR) of prior art is an inductor of fixed value. Many CLRs used in precipitator applications have taps which can be changed manually to provide a limited selection of inductance values.
  • the CLR 24 limits the current flow during sparking. If a spark occurs while an SCR is conducting, the spark continues until the SCR stops conducting near the end of the half-cycle. During this time, the TR set 22 effectively has a short on its secondary due to the spark and this is reflected into the primary. A properly designed TR set 22 has some circuit impedance, even with a spark, but it is not enough to significantly limit the current. Since the SCR 12 is fully turned on and the TR set 22 presents a low impedance due to the spark, the only circuit element remaining to control current flow is the CLR. Because of this, it is important that the CLR 24 have the right inductance value to control spark currents.
  • Another function of the CLR 24 is to shape the voltage and current waveforms.
  • the wave shape of the voltage and current presented at the primary of the TR set 22 must be a sine wave 28. Because the SCRs 16 and 18 chop and thereby distort the current waveform, the CLR 24 is needed to filter and restore the waveform to some approximation of the sine wave. Selecting the proper inductance value of the CLR 24 is important for this function as well. Historically, the inductance value of the CLR 24 has been determined by using a figure of 50 percent of the impedance of the TR set 22. Vector analysis of the voltages in the primary circuit of the TR set 22
  • the voltage on the primary of the TR set 22 is assumed to be at a zero-degree phase angle such that TR set 22 is purely resistive.
  • the voltage is set at its maximum value, which is the primary voltage rating of the example TR set 22, or 400 VAC.
  • the voltage across the CLR 24 is assumed to be at a 90-degree phase angle such that the CLR 24 is purely inductive. The voltage is to be determined.
  • the problem presents itself as a right triangle.
  • the voltage output from the SCR stack 12 forms the hypotenuse of the triangle. If the SCRs 16 and 18 are assumed to be at or near full conduction, i.e., a zero-degree firing angle and a 180-degree conduction angle, the magnitude of the hypotenuse will be approximately equal to the line
  • the CLR voltage is found to be the square root of 42,500, or 206 volts, approximately half the voltage on the TR set primary.
  • the impedance of the CLR 24 is approximately half that of the TR set 22.
  • the needed inductance is determined by
  • the CLR value has been selected for operation at the current limit rating of the example TR set. For operation at a lower current, a correspondingly larger inductance value could be used. This would have the practical effect of reducing spark currents, significantly lengthening the life of equipment. However, this would also limit the amount of current that could be applied to the TR set 22 and therefore restrict its output to a lower current. Many TR sets 22 are operated below their rated limited. Measuring Resultant Precipitator Wave Shapes - Once the values and ratings of the components of the precipitator power supply are determined, the
  • characteristics of the primary and secondary voltages and currents can be measured to determine if those values and ratings are correct. Recall that the CLR inductance value was calculated to provide nearly full conduction of the SCR stack output when the TR set is operating at its maximum ratings. This will provide a primary current wave shape that will be very nearly a sine wave 28. The secondary current wave shape will be very nearly a full-wave rectified sine wave. Two electrical measurements can be made to determine how closely the wave shapes
  • Precipitator power supplies operating at maximum ratings are normally designed to operate at a form factor of 1.2.
  • fractional conduction data These indicate how closely the waveforms approximated a sine wave 28 at the primary of the TR set 22 and a full-wave rectified sine wave on the secondary.
  • the TR set 22 has the ratings presented on page 13, and a turns ratio of 1:135.
  • variable CLR and CLR control 26 for the purpose of maintaining a low form factor and a high secondary fractional conduction at any given power level, thereby increasing the average voltage and current in the
  • the secondary voltage is not subject to corresponding analysis because of the capacitive nature of the precipitator field.
  • the voltage-current (VI) graph ( Figure 4) illustrates that the secondary voltage also increases as the form factor decreases.
  • the graph on Figure 4 is for a precipitator power supply used in a refuse burning application. Its ratings are:
  • the first shows the voltages and currents in the precipitator field with the fixed-value CLR supplied by the manufacturer. At the primary current limit of 61A, the secondary current limit of 400 mA could not be attained. The maximum secondary current possible was 332 mA.
  • the second plot shows the voltages and currents in the precipitator field with a prototype variable CLR.
  • the practical limit to which the high voltage can be raised is governed by the electrical ratings of the equipment or by sparking in the precipitator field.
  • This voltage is determined by several factors, including gas chemistry. When this voltage level is reached, voltage cannot be raised beyond it. An ideal precipitator power supply will apply power in such a manner that the peak value of the secondary voltage and current are near the average value. This will produce the maximum average secondary voltage and current before spark-over occurs.
  • this invention is designed to maximize particulate collection efficiency by devising a variable CLR 24 for the purpose of maintaining a low form factor and a high secondary fractional conduction at any given power level, thereby increasing the average voltage and current in the precipitator field before spark-over occurs.
  • sparking in the precipitator field, energy management, or any condition that causes operation of the TR set below its rated limits will cause an increased form factor and a decreased secondary fractional conduction, resulting in operating inefficiencies.
  • the voltage level at which a spark occurs changes constantly because of dynamics of the gas
  • the impedance of the CLR 24 must be dynamically adjustable.
  • variable CLR 24 that can be dynamically adjusted by being varied electrically and automatically for the purpose of maintaining a low form factor and a high secondary fractional conduction at any power level.
  • This precipitator power supply is designed to have a full-wave rectified sine wave output from the TR set 22. This will contribute to the electrical and particulate collection efficiencies.
  • SCRs 16 and 18 paired with a fixed-value current limiting reactor 24 have been shown to be superior to saturable core reactor systems. However, even SCR-CLR systems become inefficient when operated at any power level other than the limits for which the components were rated. This is because at any lower power level the SCRs have a reduced conduction angle resulting in a high form factor and a low secondary fractional conduction. It is therefore the objective of this invention to create current limiting reactor 24 that can be varied electrically and/or automatically for the purpose of overcoming these inefficiencies.
  • the electrically variable current-limiting reactor is an improvement over the prior art fixed-value CLRs and saturable reactor systems.
  • the EVCLR is much like a saturable reactor. Both devices have a control winding 32 which is connected to a source of DC energy. Both devices are basically inductors, the
  • the impedance of which can be varied electrically.
  • the speed at which a change applied to the control winding appears as a change in the impedance of the device is slow in both devices.
  • the range of variability of the inductance of the EVCLR is not as great as that of the saturable
  • the principal advantage of the EVCLR over the saturable reactor is that the EVCLR causes virtually no distortion to the primary current waveform, while the saturable reactor causes much distortion.
  • the distortion caused by the EVCLR can be held to low values, on the close order of less than one percent.
  • the EVCLR Since the EVCLR is slow like the saturable reactor and has a limited range of inductance adjustment, it is not suitable as a control element if used by itself. However, in precipitator systems that use SCRs paired with a fixed-value CLR, the EVCLR can replace the fixed-value CLR and yield considerable advantage. In this
  • EVCLR operation that is contemplated is that the impedance of the EVCLR would be adjusted to its minimum inductance value when the TR set 22 is operating at its rated limit. This would be approximately 50 percent of the TR set impedance, and would provide the optimum form factor of 1.2 and secondary fractional conduction of 0.86. When the TR set 22 is operated below its rated limit, the EVCLR can be adjusted electrically to increase its inductance, thereby
  • the basic configuration of the EVCLR is as shown in Figures 6 and 7.
  • the control winding 32 is operatively connected with respect to a variable DC power source 42.
  • the control winding is coupled with respect to the inductor winding means 30 which preferably takes the form of a first inductor winding means 34 and a second inductor winding means 36 which are basically identical with respect to one another.
  • the first inductor winding means 34 as shown best in Figure 7 is wound about a first core 38.
  • the second inductor winding means 36 is wound about a second core 40.
  • both the first core 38 and the second core 40 extend through the control winding 32 in opposite directions to cancel the
  • Various controls for modifying the DC current through the control winding 32 can include a manual adjustment which is based upon manual reading of form factor and/or secondary fractional conduction readings.
  • This manual adjustment furthermore could be based upon any applicable physical signal or combination of physical signals such as boiler load, coal type or temperature, etc. Furthermore the adjustment of the DC power source 42 and thus the control of the amount of DC current passing through control winding 32 can be varied by an automatic adjustment responsive to the same above-identified
  • an automatic electrically variable current limiting reactor can be designed utilizing the current at the primary of the transformer rectifier set 22 as the power source.
  • the automatic electrically variable current- limiting reactor 44 can be constructed according to schematic illustrated in Figure 5.
  • the primary winding 48 of a current transformer 46 is placed in series with the AEVCLR.
  • the secondary winding 50 of the current transformer is connected to a full-wave bridge rectifier 52.
  • the DC output of the full-wave bridge rectifier is connected to the control winding 56 of the AEVCLR.
  • This configuration provides for automatic adjustment of the current-limiting reactor 24.
  • the inductance will be inversely proportional to the primary current. As the primary current increases, the DC signal to the control winding 56 increases. This causes a proportional decrease in the inductance of the CLR
  • This configuration will automatically adjust the inductance of the AEVCLR 44 by responding to changes in operating conditions of the TR set 22, thereby maintaining a low form factor and a high secondary fractional
  • EVCLR electrically-variable current limiting reactor
  • Inductance required at rated operating current Inductance required at one-half of rated operating current;
  • Distortion should be kept at a minimal level over the entire operating range.
  • Figures 6, 7 and 8 present the general coil and core configuration of the device.
  • Two identical inductor windings 34 and 36 are mounted on two cores 38 and 40 and connected in parallel as shown. Alternating currents in the inductor windings 30 result in an alternating flux in each core.
  • the windings are connected so that the instantaneous flux coupled to the control winding, which is common to both cores, is always zero. Hence, if everything is balanced, there is no induced voltage in the control winding.
  • FIG. 6 and 7 present the general coil and core configuration of the device.
  • Two identical inductor windings 34 and 36 are mounted on two cores 38 and 40 and connected in parallel as shown. Alternating currents in the inductor windings 30 result in an alternating flux in each core.
  • the windings are connected so that the instantaneous flux coupled to the control winding, which is common to both cores, is always zero. Hence, if everything is balanced, there is no induced voltage in the control winding.
  • the center leg of the core can be magnetically coupled. Two separate core structures are not required.
  • a magnetomotive force caused by DC current in the control winding 32 does, however, cause equal magnetic drops in both cores 38 and 40. These drops cause changes in reluctance of the magnetic paths and hence changes in inductance. As such, the inductance value of the device is a function of the magnitude of the direct current in the control winding 32.
  • the EVCLR as illustrated is two inductors in parallel, each of which conducts half of the load current. Each individual inductor, therefore, must be designed for twice the required inductance and half of the rated current.
  • the EVCLR must be designed not to saturate when the full primary voltage is impressed across it. During sparking, the full primary voltage appears across the EVCLR.
  • the maximum AC flux density will therefore be limited to 16 kilogauss (one kilogauss equals 1000 lines of flux per square centimeter) at full primary voltage for M-6 29-gauge electrical steel. This density (B) can be calculated as follows:
  • E p is the system primary voltage
  • N is the number of turns
  • A is the inductor core area in square inches
  • f is the line frequency in Hertz (cycle per second).
  • the individual inductors must be designed for half the maximum continuous current expected.
  • a 110-degree Celsius (C) temperature rise is acceptable for this type of device.
  • C 110-degree Celsius
  • inductance for the example EVCLR will be 1.5 ⁇ mH at rated current and 3.0 ⁇ mH at one-half of rated current, providing a desirable and usable control range.
  • AC line current in the lines is transformed to a suitable level, then rectified.
  • This DC signal is supplied to the control winding of the EVCLR.
  • the DC signal has little ripple because of the high inductance inherent in the control winding.
  • the control current is therefore proportional to the average of the primary load current.
  • the control current is proportional to the RMS of the load current only if the form factor remains constant.
  • the EVCLR must also be operated in the more linear portion of its range as shown in the graph in Figure 8. As illustrated, the design range for the example inductor must be
  • the inductor is constructed with two different air gaps.
  • Figure 8 shows the general construction used. Each of the pair of inductors has two large air gaps and two small ones.
  • l c is the mean length of the magnetic path (steel)
  • l gx and l gu are the lengths of the air gaps in the X and U portions of the core, respectively
  • a x and A u both are the area of steel in the x and u portions, respectively.
  • the inductance range can then be calculated to be from sections U and X both being completely unsaturated (high relative permeability) to section U being completely saturated. In this condition, it is as if section U does not exist. Derivation of the design equations proceeds in this manner:
  • N turns
  • ⁇ total flux lines
  • I current
  • R reluctance
  • ⁇ r is the relative permeability of
  • u r will be considered either very high (infinite) or very low (zero).
  • R T R u R x /(R u +R x )
  • R x l gx /A x
  • R T R u R x / (R u +R x )
  • control winding must be designed and matched to the primary load current with several factors borne in mind:

Abstract

Réacteur limiteur de courant (24) électriquement variable, pouvant être utilisé en combinaison avec une alimentation électrique (14-22) pour un appareil de précipitation électrostatique (10, 58). La valeur d'inductance du réacteur limiteur de courant (24) peut varier en fonction des conditions de fonctionnement du système. En particulier, l'inductance du réacteur limiteur de courant (24) peut être modifiée en fonction du facteur de forme du courant alternatif sinusoïdal d'entrée appliqué au transformateur d'alimentation. En outre, l'inductance du réacteur limiteur de courant (24) peut être régulée en fonction de la conduction fractionnaire de la forme d'onde de courant ayant subi un redressement double alternance, à la sortie du redresseur double alternance de l'alimentation. Il est possible de surveiller d'autres conditions, telles que des paramètres physiques du système afin de réguler la valeur d'inductance du réacteur limiteur de courant (24). Une commande de fonctionnement automatique peut modifier l'inductance du réacteur limiteur de courant en fonction du courant injecté dans le primaire du transformateur de l'alimentation.
PCT/US1991/001745 1991-03-14 1991-03-14 Reacteur limiteur de courant electriquement variable pour appareils de precipitation WO1992016302A1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
PCT/US1991/001745 WO1992016302A1 (fr) 1991-03-14 1991-03-14 Reacteur limiteur de courant electriquement variable pour appareils de precipitation
DE69127815T DE69127815D1 (de) 1991-03-14 1991-03-14 Elektrische veränderliche strombegrenzende reaktanzspule für abscheider
EP91906521A EP0528805B1 (fr) 1991-03-14 1991-03-14 Reacteur limiteur de courant electriquement variable pour appareils de precipitation
CA002082056A CA2082056C (fr) 1991-03-14 1991-03-14 Un reacteur limiteur de courant electriquement variable pour precipitateurs

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PCT/US1991/001745 WO1992016302A1 (fr) 1991-03-14 1991-03-14 Reacteur limiteur de courant electriquement variable pour appareils de precipitation

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US2843215A (en) * 1953-07-02 1958-07-15 Research Corp Automatic precipitator control
US3873282A (en) * 1972-07-27 1975-03-25 Gen Electric Automatic voltage control for an electronic precipitator
DD205342A1 (de) * 1982-05-07 1983-12-28 Alois Hahn Verfahren und vorrichtung zum betrieb von elektroabscheidern
US4808200A (en) * 1986-11-24 1989-02-28 Siemens Aktiengesellschaft Electrostatic precipitator power supply

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Also Published As

Publication number Publication date
EP0528805B1 (fr) 1997-10-01
EP0528805A4 (en) 1993-03-17
DE69127815D1 (de) 1997-11-06
CA2082056A1 (fr) 1992-09-15
EP0528805A1 (fr) 1993-03-03
CA2082056C (fr) 1996-09-10

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