EP0038505B1 - Method of automatically bringing the voltage of an electrofilter to the discharge limit - Google Patents

Method of automatically bringing the voltage of an electrofilter to the discharge limit Download PDF

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Publication number
EP0038505B1
EP0038505B1 EP81102820A EP81102820A EP0038505B1 EP 0038505 B1 EP0038505 B1 EP 0038505B1 EP 81102820 A EP81102820 A EP 81102820A EP 81102820 A EP81102820 A EP 81102820A EP 0038505 B1 EP0038505 B1 EP 0038505B1
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European Patent Office
Prior art keywords
voltage
breakdown
time
filter
follow
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EP81102820A
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German (de)
French (fr)
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EP0038505A1 (en
Inventor
Helmut Dipl.-Ing. Herklotz
Günter Mehler
Franz Dipl.-Ing. Neulinger
Helmut Dipl.-Ing. Schummer
Horst Dr. Dipl.-Ing. Daar
Walter Dipl.-Ing. Schmidt
Heinrich Winkler
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GEA Group AG
Siemens AG
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Metallgesellschaft AG
Siemens AG
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Priority to AT81102820T priority Critical patent/ATE6912T1/en
Publication of EP0038505A1 publication Critical patent/EP0038505A1/en
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B03SEPARATION 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
    • B03CMAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/34Constructional details or accessories or operation thereof
    • B03C3/66Applications of electricity supply techniques
    • B03C3/68Control systems therefor
    • YGENERAL 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
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S323/00Electricity: power supply or regulation systems
    • Y10S323/903Precipitators

Definitions

  • the invention relates to a method for automatically guiding the voltage of an electrostatic precipitator at the breakdown limit by increasing the filter voltage as a function of time until it breaks down and then reducing it by a predetermined amount to a new value.
  • the degree of separation of an electrostatic precipitator is higher the closer the operating voltage is to the flashover limit. Since the rollover limit changes during operation depending on several influencing factors, such as. B. gas composition, dust content and temperature changes, the voltage of the electrostatic precipitator must be controlled depending on the amount of the rollover limit.
  • Devices for voltage regulation are known in which the voltage is increased as a function of time up to the rollover limit. If one or more rollovers occur, the voltage is reduced by a certain, predetermined amount below the rollover limit and then increased again to the rollover limit.
  • a control capacitor is charged via a resistor depending on the filter current.
  • a continuously controllable tube is connected in parallel to this control capacitor, which in turn is controlled by a capacitor.
  • This capacitor is charged depending on the breakdown and continuously discharged via a parallel resistor.
  • the voltage at the control capacitor serves as a control voltage for a primary-side actuator.
  • the object of the present invention is therefore to design the method of the type mentioned in the introduction in such a way that consequential breakthroughs are avoided as far as possible.
  • the filter voltage is reduced to zero in the case of a further breakdown following a breakdown, the so-called follow-through breakdown, within a predetermined time period, and is brought up to the new value after a predetermined pause within a predetermined ramp-up period , whereby the breakthrough follow-up time is selected somewhat larger than the sum of the break and run-up time.
  • the control voltage for an actuator is then carried out so that its number remains as small as possible.
  • pause and run-up times are also advantageously made dependent on the number of subsequent copies in a previous, predetermined search period; d. H. If there were many follow-up copies in the previous search period, the pause duration and the ramp-up time are chosen to be relatively long and vice versa. This means that both the recording criterion for subsequent copies and their treatment follow the parameter subsequent copies themselves. Furthermore, the search period can also be made dependent on the number of copies.
  • the voltage or current is reduced after each breakdown.
  • a reduction in the current breakdown voltage or current is selected for the reduction, the percentage being dependent on the breakdown frequency in a previously defined period of time.
  • the power supply of an electrostatic filter normally consists of a thyristor actuator, which is arranged between the mains and a high-voltage transformer, and a rectifier connected downstream.
  • a microcomputer system is advantageously used within the scope of the present invention, which calculates the required control voltage from the existing values and stored operating parameters.
  • a breakthrough D may occur at time To. If the next breakdown lies within the so-called breakthrough time t F z. B. at T 1 , this breakdown is treated as a subsequent breakdown D F. If the breakthrough occurred outside the breakthrough follow-up time t F at time TY, it would happen again a normal breakthrough.
  • the breakthrough time t F is defined as
  • the pause time tp is to be understood as the pause or deionization time which should pass until the voltage is increased again after the control voltage has dropped to zero. This time is advantageously made automatically dependent on the frequency of the subsequent copies in a previous search period, i. H. if there were many subsequent runs, this pause time tp is increased and vice versa.
  • the run-up time t H is defined as the time that passes until the voltage is brought up to the new value. This time is also advantageously made dependent on the number of follow-through copies of a given search period, in the same way as the pause time, ie the increase is slowed down with increasing frequency, ie the run-up time is increased and vice versa. For safety henceforth nor the time T / 2 is then taken into account in the calculation of the penetration time sequence, wherein T under the power supply period of 20 ms and 16 2/3 ms is understood.
  • a breakdown D occurs at the time T o , as can be seen from the corresponding breakdown of the filter voltage U F or the increase in the filter current I F.
  • the control voltage Ust for the actuator is reduced by the amount L tU s t, so that a filter voltage would result in the subsequent half-wave which is lower than the previous voltage by the value UP.
  • This voltage drop UP can be selected as a percentage of the pulsating filter DC voltage that is currently present.
  • a new breakdown occurs at the time T 1 within the breakthrough follow-up time to be defined after the breakdown D, so that this breakdown is to be regarded as a subsequent breakdown D F.
  • the control voltage U st for the actuator is set to zero and the filter voltage is also reduced accordingly. Since this is the first subsequent breakdown, a pause time, ie a deionization time, is not taken into account and the filter voltage is gradually increased again within the period t H to the new value U FN of the filter voltage with the current value I FN . From this value, the breakdown limit is then sought again in a manner known per se by increasing the voltage as a function of time.
  • Fig. 3 shows the circuit implementation of the arrangement.
  • an AC voltage network 1 feeds the primary side of a high-voltage transformer 3 via a thyristor actuator 2.
  • a rectifier 4 is connected to the secondary side of the high-voltage transformer 3 and supplies the filter DC voltage for the electrostatic filter 5.
  • the control voltage U st for the control rate 21 of the thyristor actuator 2 is carried out by a digital controller 6, which - as indicated by the equal sign - today generally consists of a microcomputer system 7.
  • This system has the main components of the central unit 71, the memory 72 and the input and output devices 73. For the sake of easier understanding, however, the individual functions of this microcomputer system are shown as function blocks in the controller 6.
  • a breakdown detection 62 is provided which derives the criterion for the breakdown from the primary current and / or filter voltage, e.g. B. in such a way that it is checked whether the voltage in the current half-wave of the filter DC voltage falls below the corresponding values of the same phase position in the previous half-wave of the filter DC voltage. If a breakdown occurs, the voltage reduction element 63 generates a correspondingly reduced control voltage U st via the voltage regulator 61 and thus the filter voltage is lowered by the value OPEN. After a certain period of time has elapsed, this voltage is raised again to the breakdown limit using a predetermined gradient - gradient selector 64, whereupon the game described above is repeated.
  • the primary current and / or filter voltage e.g. B.
  • a follow-up breakdown detection 66 is connected to the breakdown detection 62 via a test stage 65; This reports breakthroughs that lie within the so-called breakthrough follow-up time t F as follow-through breakthroughs to the follow-through breakthrough detection element 66.
  • pause time tp and time t H of the increase as well as the breakthrough follow-up time are regarded as a function of the number of follow-through copies D F within a predetermined search period, a value proportional to the number h of follow-up copies within a given search period is also stored in a follow-through copy memory 67 and as appropriate size used to determine the breakthrough follow-up time and the other times.

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  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Electrostatic Separation (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)
  • Rectifiers (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)

Abstract

A system for automatically controlling the voltage of an electrostatic filter with respect to its breakdown voltage limit. The detection of secondary voltage breakdowns which occur within a post-breakdown time period after an initial voltage breakdown cause the filter voltage to be lowered to zero value. After a deionizing time period, the filter voltage is gradually raised during a predetermined rise time period until it reaches a new value. The duration of the deionizing time period and the rise time period may be advantageously computed in response to the history of voltage breakdowns, by a microcomputer system.

Description

Die Erfindung bezieht sich auf ein Verfahren zum selbsttätigen Führen der Spannung eines Elektrofilters an der Durchschlagsgrenze durch zeitabhängige Steigerung der Filterspannung bis zum Durchschlag und anschließende durchschlagsabhängige Absenkung um einen vorgegebenen Betrag auf einen neuen Wert.The invention relates to a method for automatically guiding the voltage of an electrostatic precipitator at the breakdown limit by increasing the filter voltage as a function of time until it breaks down and then reducing it by a predetermined amount to a new value.

Der Abscheidegrad eines elektrostatischen Abscheiders ist um so höher, je näher die Betriebsspannung an der Überschlagsgrenze liegt. Da sich die Überschlagsgrenze während des Betriebs in Abhängigkeit von mehreren Einflußgrößen, wie z. B. Gaszusammensetzung, Staubgehalt und Temperatur ändert, muß die Spannung des elektrostatischen Abscheiders in Abhängigkeit von der Höhe der Überschlagsgrenze geregelt werden.The degree of separation of an electrostatic precipitator is higher the closer the operating voltage is to the flashover limit. Since the rollover limit changes during operation depending on several influencing factors, such as. B. gas composition, dust content and temperature changes, the voltage of the electrostatic precipitator must be controlled depending on the amount of the rollover limit.

Es sind Einrichtungen zur Spannungsregelung bekannt, bei denen die Spannung bis an die Überschlagsgrenze zeitabhängig erhöht wird. Kommen ein oder mehrere Überschläge, so wird die Spannung um einen bestimmten, fest vorgegebenen Betrag unter die Überschlagsgrenze abgesenkt und anschließend wieder bis zur Überschlagsgrenze erhöht.Devices for voltage regulation are known in which the voltage is increased as a function of time up to the rollover limit. If one or more rollovers occur, the voltage is reduced by a certain, predetermined amount below the rollover limit and then increased again to the rollover limit.

Bei einem aus der DE-AS 1 148 977 bekanntgewordenen Verfahren wird über einen Widerstand ein Regelkondensator filterstromabhängig aufgeladen. Als Entladewiderstand ist diesem Regelkondensator eine stetig steuerbare Röhre parallelgeschaltet, die ihrerseits wieder von einem Kondensator angesteuert wird. Dieser Kondensator wird durchschlagsabhängig aufgeladen und fortlaufend über einen Parallelwiderstand entladen. Die Spannung am Regelkondensator dient als Steuerspannung für ein primärseitiges Stellglied.In a method which has become known from DE-AS 1 148 977, a control capacitor is charged via a resistor depending on the filter current. As a discharge resistor, a continuously controllable tube is connected in parallel to this control capacitor, which in turn is controlled by a capacitor. This capacitor is charged depending on the breakdown and continuously discharged via a parallel resistor. The voltage at the control capacitor serves as a control voltage for a primary-side actuator.

Steuerverfahren und deren schaltungstechnische Realisierung sind ferner auch in der Siemens Zeitschrift 1971, Seiten 567-572 näher beschrieben.Control methods and their circuitry implementation are also described in more detail in Siemens magazine 1971, pages 567-572.

Es kommt nun vor, daß nach einem Durchschlag sofort ein oder mehrere weitere Durchschläge folgen. Dies ist im Regelfall unerwünscht, da während der Durchschlagszeit die eigentliche Abscheidewirkung entfällt.It now happens that one or more further copies follow immediately after a copy. This is usually undesirable since the actual separation effect is eliminated during the breakthrough time.

Die Aufgabe der vorliegenden Erfindung besteht daher darin, das Verfahren der eingangs genannten Art so auszugestalten, daß Folgedurchschläge möglichst vermieden werden.The object of the present invention is therefore to design the method of the type mentioned in the introduction in such a way that consequential breakthroughs are avoided as far as possible.

Diese Aufgabe wird erfindungsgemäß dadurch gelöst, daß bei einem innerhalb einer vorgegebenen Zeitdauer, der sog. Durchbruchsfolgezeit auf einen Durchschlag folgenden weiteren Durchschlag, dem sog. Folgedurchschlag die Filterspannung auf Null verringert und nach einer vorgegebenen Pause innerhalb einer vorgegebenen Hochlaufdauer auf den neuen Wert hochgeführt wird, wobei die Durchbruchsfolgezeit etwas größer als die Summe aus Pausen- und Hochlaufzeit gewählt ist. Auf diese Weise liegt ein Kriterium vor, mit dem zwischen Normaldurchschlägen und Folgedurchschlägen unterschieden werden kann. Bei den Folgedurchschlägen wird dann die Steuerspannung für ein Stellglied so geführt, daß ihre Zahl möglichst gering bleibt.This object is achieved in that the filter voltage is reduced to zero in the case of a further breakdown following a breakdown, the so-called follow-through breakdown, within a predetermined time period, and is brought up to the new value after a predetermined pause within a predetermined ramp-up period , whereby the breakthrough follow-up time is selected somewhat larger than the sum of the break and run-up time. In this way, there is a criterion with which a distinction can be made between normal carbon and subsequent carbon dioxide. In the subsequent breakdowns, the control voltage for an actuator is then carried out so that its number remains as small as possible.

Zur besseren Adaptierung an die tatsächlichen Filterverhältnisse werden vorteilhafterweise auch Pausen- und Hochlaufzeit von der Zahl der Folgedurchschläge in einer vorhergehenden, vorgegebenen Suchperiode abhängig gemacht; d. h. waren in der vorhergehenden Suchperiode viele Folgedurchschläge zu verzeichnen, so wird die Pausendauer und die Hochlaufzeit relativ groß gewählt und umgekehrt. Damit folgen sowohl das Erfassungskriterium für Folgedurchschläge als auch deren Behandlung dem Parameter Folgedurchschlag selbst. Weitergehend kann auch noch die Suchperiode von der Zahl der Durchschläge abhängig gemacht werden.In order to better adapt to the actual filter conditions, pause and run-up times are also advantageously made dependent on the number of subsequent copies in a previous, predetermined search period; d. H. If there were many follow-up copies in the previous search period, the pause duration and the ramp-up time are chosen to be relatively long and vice versa. This means that both the recording criterion for subsequent copies and their treatment follow the parameter subsequent copies themselves. Furthermore, the search period can also be made dependent on the number of copies.

Wie bereits einleitend bemerkt, wird nach jedem Durchschlag die Spannung bzw. auch der Strom abgesenkt. Vorteilhafterweise wird für die Absenkung jeweils ein prozentualer Betrag der gerade vorliegenden Durchbruchsspannung bzw. des Stromes gewählt, wobei der Prozentsatz von der Durchschlagshäufigkeit in einer vorhergehenden festgelegten Zeitperiode abhängig sein kann.As already mentioned in the introduction, the voltage or current is reduced after each breakdown. Advantageously, a reduction in the current breakdown voltage or current is selected for the reduction, the percentage being dependent on the breakdown frequency in a previously defined period of time.

Die Stromversorgung eines Elektrofilters besteht normalerweise aus einem Thyristorstellglied, das zwischen Netz und einem Hochspannungstransformator angeordnet ist und einem nachgeschalteten Gleichrichter. Zur Vorgabe der Steuerspannung für das Stellglied wird vorteilhafterweise im Rahmen der hier vorliegenden Erfindung ein Mikrocomputersystem benutzt, das aus den vorhandenen Werten und gespeicherten Betriebsparametern die erforderliche Steuerspannung berechnet.The power supply of an electrostatic filter normally consists of a thyristor actuator, which is arranged between the mains and a high-voltage transformer, and a rectifier connected downstream. To specify the control voltage for the actuator, a microcomputer system is advantageously used within the scope of the present invention, which calculates the required control voltage from the existing values and stored operating parameters.

Anhand eines in der Zeichnung dargestellten Ausführungsbeispiels sei die Erfindung näher beschrieben; es zeigt

  • Fig. 1 eine schematische Skizze zur Verdeutlichung des Begriffes des Folgedurchschlags,
  • Fig. 2 einen beispielsweisen Verlauf von Filterspannung, Filterstrom und Steuerspannung des Stellgliedes aufgetragen über der Zeit und
  • Fig. 3 die Spannungsversorgung eines Elektrofilters mit dazugehöriger Regelung nach dem erfindungsgemäßen Steuerverfahren.
The invention will be described in more detail using an exemplary embodiment shown in the drawing; it shows
  • 1 is a schematic sketch to clarify the term follow-through breakdown,
  • Fig. 2 shows an exemplary course of the filter voltage, filter current and control voltage of the actuator plotted over time and
  • Fig. 3 shows the voltage supply of an electrostatic filter with associated control according to the control method according to the invention.

Nach einem Durchschlag wird zunächst unterschieden, ob es sich um einen einfachen Durchschlag D oder einen Folgedurchschlag DF handelt.After a breakdown, a distinction is first made as to whether it is a simple breakdown D or a subsequent breakdown D F.

Zum Zeitpunkt To möge sich ein Durchschlag D ereignen. Liegt der nächste Durchschlag innerhalb der sog. Durchbruchsfolgezeit tF z. B. bei T1 so wird dieser Durchschlag als Folgedurchschlag DF behandelt. Würde sich der Durchschlag außerhalb der Durchbruchsfolgezeit tF zum Zeitpunkt TY ereignen, würde es sich wieder um einen normalen Durchschlag handeln. Die Durchbruchsfolgezeit tF ist definiert als

Figure imgb0001
A breakthrough D may occur at time To. If the next breakdown lies within the so-called breakthrough time t F z. B. at T 1 , this breakdown is treated as a subsequent breakdown D F. If the breakthrough occurred outside the breakthrough follow-up time t F at time TY, it would happen again a normal breakthrough. The breakthrough time t F is defined as
Figure imgb0001

Als Pausenzeit tp ist die Pause bzw. die Entionisierungszeit zu verstehen, die vergehen sollte, bis nach dem Absinken der Steuerspannung auf Null wieder die Spannung erneut gesteigert wird. Diese Zeit wird mit Vorteil von der Häufigkeit der Folgedurchschläge in einer vorhergehenden Suchperiode selbsttätig abhängig gemacht, d. h. lagen viele Folgedurchschläge vor, wird diese Pausenzeit tp erhöht und umgekehrt.The pause time tp is to be understood as the pause or deionization time which should pass until the voltage is increased again after the control voltage has dropped to zero. This time is advantageously made automatically dependent on the frequency of the subsequent copies in a previous search period, i. H. if there were many subsequent runs, this pause time tp is increased and vice versa.

Als Hochlaufzeit tH wird diejenige Zeit definiert, die vergeht, bis die Spannung auf den neuen Wert hochgeführt ist. Auch diese Zeit wird mit Vorteil von der Zahl der Folgedurchschläge einer vorgegebenen Suchperiode abhängig gemacht und zwar in gleicher Weise wie die Pausenzeit, d. h. mit zunehmender Durchschlagshäufigkeit wird der Anstieg verlangsamt, d. h. die Hochlaufzeit vergrößert und umgekehrt. Zur Sicherheit ist dann fernerhin noch die Zeit T/2 bei der Berechnung der Durchbruchsfolgezeit zu berücksichtigen, wobei unter T die Netzperiode mit 20 ms bzw. 162/3 ms verstanden wird.The run-up time t H is defined as the time that passes until the voltage is brought up to the new value. This time is also advantageously made dependent on the number of follow-through copies of a given search period, in the same way as the pause time, ie the increase is slowed down with increasing frequency, ie the run-up time is increased and vice versa. For safety henceforth nor the time T / 2 is then taken into account in the calculation of the penetration time sequence, wherein T under the power supply period of 20 ms and 16 2/3 ms is understood.

Wie aus Fig. ersichtlich, ereignet sich zum Zeitpunkt To ein Durchschlag D, wie aus dem entsprechenden Zusammenbruch der Filterspannung UF bzw. dem Anstieg des Filterstroms IF ersichtlich ist. Als Reaktion auf diesen normalen Durchschlag wird die Steuerspannung Ust für das Stellglied um den Betrag LtUst verringert, so daß sich bei der nachfolgenden Halbwelle eine Filterspannung ergeben würde, die um den Wert AUF niedriger als die vorhergehende Spannung ist. Diese Spannungsabsenkung AUF kann dabei zu einem prozentualen Wert der gerade vorliegenden pulsierenden Filtergleichspannung gewählt werden.As can be seen from FIG. 1, a breakdown D occurs at the time T o , as can be seen from the corresponding breakdown of the filter voltage U F or the increase in the filter current I F. In response to this normal breakdown, the control voltage Ust for the actuator is reduced by the amount L tU s t, so that a filter voltage would result in the subsequent half-wave which is lower than the previous voltage by the value UP. This voltage drop UP can be selected as a percentage of the pulsating filter DC voltage that is currently present.

Wie ferner aus Fig. 2 ersichtlich, ereignet sich zum Zeitpunkt T1 also innerhalb der nach dem Durchschlag D zu definierenden Durchbruchsfolgezeit ein neuer Durchschlag, so daß dieser Durchschlag als Folgedurchschlag DF zu betrachten ist. Als Reaktion auf diesen Folgedurchschlag DF wird die Steuerspannung Ust für das Stellglied auf Null gesetzt und damit die Filterspannung ebenfalls entsprechend herabgesetzt. Da es sich um den ersten Folgedurchschlag handelt wird eine Pausenzeit, d. h. eine Entionisierungszeit nicht berücksichtigt und die Filterspannung innerhalb des Zeitraumes tH schrittweise wieder bis zum neuen Wert UFN der Filterspannung mit dem Stromwert IFN gesteigert. Von diesem Wert aus wird dann in an sich bekannter Weise durch zeitabhängige Erhöhung der Spannung wieder die Durchschlagsgrenze gesucht.As can further be seen from FIG. 2, a new breakdown occurs at the time T 1 within the breakthrough follow-up time to be defined after the breakdown D, so that this breakdown is to be regarded as a subsequent breakdown D F. In response to this subsequent breakdown D F , the control voltage U st for the actuator is set to zero and the filter voltage is also reduced accordingly. Since this is the first subsequent breakdown, a pause time, ie a deionization time, is not taken into account and the filter voltage is gradually increased again within the period t H to the new value U FN of the filter voltage with the current value I FN . From this value, the breakdown limit is then sought again in a manner known per se by increasing the voltage as a function of time.

Fig. 3 zeigt die schaltungsmäßige Realisierung der Anordnung. Wie ersichtlich, speist ein Wechselspannungsnetz 1 über ein Thyristorstellglied 2 die Primärseite eines Hochspannungstransformators 3. An die Sekundärseite des Hochspannungstransformators 3 ist ein Gleichrichter 4 angeschlossen, der die Filtergleichspannung für das Elektrofilter 5 liefert. Die Führung der Steuerspannung Ust für den Steuersatz 21 des Thyristorstellgliedes 2 wird von einem Digitalregler 6 vorgenommen, der - wie durch das Gleichheitszeichen angedeutet -, heute im Regelfall aus einem Mikrocomputersystem 7 besteht. Dieses System hat als wesentliche Komponenten die Zentraleinheit 71, den Speicher 72 und die Ein- und Ausgabegeräte 73. Der leichteren Verständlichkeit halber sind jedoch die einzelnen Funktionen dieses Mikrocomputersystems als Funktionsbausteine im Regler 6 dargestellt.Fig. 3 shows the circuit implementation of the arrangement. As can be seen, an AC voltage network 1 feeds the primary side of a high-voltage transformer 3 via a thyristor actuator 2. A rectifier 4 is connected to the secondary side of the high-voltage transformer 3 and supplies the filter DC voltage for the electrostatic filter 5. The control voltage U st for the control rate 21 of the thyristor actuator 2 is carried out by a digital controller 6, which - as indicated by the equal sign - today generally consists of a microcomputer system 7. This system has the main components of the central unit 71, the memory 72 and the input and output devices 73. For the sake of easier understanding, however, the individual functions of this microcomputer system are shown as function blocks in the controller 6.

Wie ersichtlich, ist eine Durchschlagserfassung 62 vorgesehen, die aus Primärstrom und/oder Filterspannung das Kriterium für den Durchschlag ableitet, z. B. in der Weise, daß geprüft wird, ob die Spannung in der gerade vorliegenden Halbwelle der Filtergleichspannung die entsprechenden Werte gleicher Phasenlage in der vorhergehenden Halbwelle der Filtergleichspannung unterschreitet. Ereignet sich ein Durchschlag, so wird durch das Spannungsabsenkungsglied 63 über den Spannungsregler 61 eine entsprechend verringerte Steuerspannung Ust erzeugt und damit die Filterspannung um den Wert AUF abgesenkt. Nach Ablauf einer bestimmten Zeitdauer wird diese Spannung mit einem vorgegebenen Gradienten - Gradientenwähler 64 - wieder bis zur Durchschlagsgrenze angehoben, worauf sich dann das vorstehend beschriebene Spiel wiederholt.As can be seen, a breakdown detection 62 is provided which derives the criterion for the breakdown from the primary current and / or filter voltage, e.g. B. in such a way that it is checked whether the voltage in the current half-wave of the filter DC voltage falls below the corresponding values of the same phase position in the previous half-wave of the filter DC voltage. If a breakdown occurs, the voltage reduction element 63 generates a correspondingly reduced control voltage U st via the voltage regulator 61 and thus the filter voltage is lowered by the value OPEN. After a certain period of time has elapsed, this voltage is raised again to the breakdown limit using a predetermined gradient - gradient selector 64, whereupon the game described above is repeated.

Zusätzlich zu den Durchschlägen D werden auch die Folgedurchschläge DF erfaßt. Hierzu ist mit der Durchschlagserfassung 62 eine Folgedurchschlagserfassung 66 über eine Prüfstufe 65 verbunden; diese meldet Durchschläge, die innerhalb der sog. Durchbruchsfolgezeit tF liegen als Folgedurchschläge an das Folgedurchschlagserfassungsglied 66.In addition to the carbon copies D, the subsequent carbon copies D F are also recorded. For this purpose, a follow-up breakdown detection 66 is connected to the breakdown detection 62 via a test stage 65; This reports breakthroughs that lie within the so-called breakthrough follow-up time t F as follow-through breakthroughs to the follow-through breakthrough detection element 66.

Dieses bewirkt dann über das Spannungsabsenkungsglied 68 die Herabsetzung der Filterspannung bzw. der Steuerspannung auf Null und deren langsamen Anstieg bis zum vorgegebenen neuen Spannungswert. Da Pausenzeit tp und Zeit tH des Anstieges ebenso wie die Durchbruchsfolgezeit als Funktion der Zahl der Folgedurchschläge DF innerhalb einer vorgegebenen Suchperiode angesehen werden, wird in einem Folgedurchschlagspeicher 67 auch noch ein der Zahl h der Folgedurchschläge innerhalb einer vorgegebenen Suchperiode proportionaler Wert gespeichert und als entsprechende Größe zur Festlegung der Durchbruchsfolgezeit und der anderen Zeiten verwendet.This then causes the filter voltage or control voltage to be reduced to zero via the voltage reduction element 68 and slowly increases to the predetermined new voltage value. Since pause time tp and time t H of the increase as well as the breakthrough follow-up time are regarded as a function of the number of follow-through copies D F within a predetermined search period, a value proportional to the number h of follow-up copies within a given search period is also stored in a follow-through copy memory 67 and as appropriate size used to determine the breakthrough follow-up time and the other times.

Claims (4)

1. Method of automatically guiding the voltage of an electrostatic filter (4) to the breakdown limit by the time-dependent increase of the filter voltage (UF) up to breakdown (D) and subsequent breakdown-dependent decrease (AUF) by a predetermined amount to a new value, characterised in that in the event of a further breakdown, the so-called secondary breakdown (DF), following a breakdown '(D) within a predetermined period of time, the so-called breakdown follow-up time (tF), the filter voltage (UF) is reduced to zero and, after a predertermin- able pause (tp), is increased to the new value within a predetermined run-up time (tH), the breakdown follow-up time (tF) being selected to be somewhat longer than the sum of pause and run-up times.
2. Method according to claim 1, characterised in that the pause and run-up times (tp, tH) are made to be dependent on the number (h) of secondary breakdowns (DF) within a predetermined search period.
3. Method according to claim 2, characterised in that the length of the search period is made to be dependent on the number (h) of breakdowns.
4. Method according to claim 1, characterised in that the voltage (UF) is reduced after each breakdown (D) by a percentage amount (ΔUr), which is dependent on the frequency of breakdowns in a previously determined period of time.
EP81102820A 1980-04-21 1981-04-13 Method of automatically bringing the voltage of an electrofilter to the discharge limit Expired EP0038505B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT81102820T ATE6912T1 (en) 1980-04-21 1981-04-13 PROCEDURE FOR AUTOMATICALLY CARRYING THE VOLTAGE OF AN ELECTRICAL FILTER AT THE BREAKDOWN LIMIT.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3015275 1980-04-21
DE19803015275 DE3015275A1 (en) 1980-04-21 1980-04-21 METHOD FOR AUTOMATICALLY LEADING THE VOLTAGE OF AN ELECTROFILTER AT THE DISTANCE LIMIT

Publications (2)

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EP0038505A1 EP0038505A1 (en) 1981-10-28
EP0038505B1 true EP0038505B1 (en) 1984-04-04

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US (1) US4382805A (en)
EP (1) EP0038505B1 (en)
JP (1) JPS56163764A (en)
AT (1) ATE6912T1 (en)
AU (1) AU534502B2 (en)
DE (2) DE3015275A1 (en)
ZA (1) ZA812550B (en)

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* Cited by examiner, † Cited by third party
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WO1983000297A1 (en) * 1981-07-24 1983-02-03 Rodney John Truce Detecting, measuring and applying back corona parameters on an electrostatic precipitator
DE3233249C2 (en) * 1982-09-08 1986-10-02 Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt Method for controlling an electrostatic precipitator and control device for carrying out the method
JPS6125650A (en) * 1984-07-17 1986-02-04 Sumitomo Heavy Ind Ltd Method for controlling electrical charge of electrical dust precipitator
DK552186A (en) * 1986-11-19 1988-05-20 Smidth & Co As F L METHOD AND APPARATUS FOR DETECTING RETURN RADIATION IN AN ELECTROFILTER WITH GENERAL OR INTERMITTING POWER SUPPLY
DE4220658C1 (en) * 1992-06-24 1993-03-18 Metallgesellschaft Ag, 6000 Frankfurt, De
DE4222069A1 (en) * 1992-07-04 1994-01-05 Rothemuehle Brandt Kritzler Comparing electrical wood filter dust arcing activity with arcing in dust-free passage - to control voltage level below arcing threshold, maximising efficiency without increase in fire risk
US7081152B2 (en) * 2004-02-18 2006-07-25 Electric Power Research Institute Incorporated ESP performance optimization control
CN103752413B (en) * 2014-01-24 2016-03-23 镇江天力变压器有限公司 A kind of secondary voltage modulate circuit of high-frequency dust removing power supply

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US3577708A (en) * 1968-05-28 1971-05-04 Koppers Co Inc Spark interval responsive precipitator voltage control
US3648437A (en) * 1969-07-23 1972-03-14 Koppers Co Inc Automatic scr precipitator control
US3745749A (en) * 1971-07-12 1973-07-17 Envirotech Corp Circuits for controlling the power supplied to an electrical precipitator
US3873282A (en) * 1972-07-27 1975-03-25 Gen Electric Automatic voltage control for an electronic precipitator
CA1089002A (en) * 1976-08-13 1980-11-04 Richard K. Davis Automatic control system for electric precipitators
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DE2949764A1 (en) * 1979-12-11 1981-07-02 Metallgesellschaft Ag, 6000 Frankfurt METHOD FOR AUTOMATICALLY LEADING THE VOLTAGE OF AN ELECTROFILTER AT THE DISTANCE LIMIT

Also Published As

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US4382805A (en) 1983-05-10
AU534502B2 (en) 1984-02-02
JPS6124053B2 (en) 1986-06-09
EP0038505A1 (en) 1981-10-28
JPS56163764A (en) 1981-12-16
DE3015275A1 (en) 1981-10-22
ZA812550B (en) 1982-04-28
AU6956581A (en) 1981-10-29
ATE6912T1 (en) 1984-04-15
DE3162931D1 (en) 1984-05-10

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