EP0035209A1 - Process for operating an electrofilter - Google Patents

Process for operating an electrofilter Download PDF

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Publication number
EP0035209A1
EP0035209A1 EP81101300A EP81101300A EP0035209A1 EP 0035209 A1 EP0035209 A1 EP 0035209A1 EP 81101300 A EP81101300 A EP 81101300A EP 81101300 A EP81101300 A EP 81101300A EP 0035209 A1 EP0035209 A1 EP 0035209A1
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EP
European Patent Office
Prior art keywords
voltage
microprocessor
filter
values
control
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EP81101300A
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German (de)
French (fr)
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EP0035209B1 (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 AT81101300T priority Critical patent/ATE8110T1/en
Publication of EP0035209A1 publication Critical patent/EP0035209A1/en
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    • 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

  • the invention relates to a controller for an electrostatic filter, which is fed from an AC voltage network via an actuator and a high-voltage rectifier and in which the actuator can be controlled as a function of electrical filter operating values.
  • This generic term refers to arrangements such as are known, for example, from Siemens magazine 1971 (number 9), pages 567 to 572, in particular figure 2 or DE-AS 11 48 977.
  • filter current and filter voltage are detected and guided depending on breakdowns in such a way that optimum separation conditions result.
  • the previously known controls are generally constructed using means of analog technology, that is to say amplifiers, resistors and capacitors, etc. As digital technology advances, it is desirable to use the microprocessor for control purposes.
  • the object of the present invention is to provide a universally applicable and simple control for electrostatic filters on a microprocessor basis, which is very versatile with regard to measured value acquisition and processing, but at the same time also has sufficient time available for superordinate control purposes.
  • the electrical filter operating values can be queried and stored multiple times by a microprocessor in a cycle comprising a maximum of 1/2 period of the mains alternating voltage, the microprocessor in each case the required current and voltage values to the control signal of the at the end of the sampling cycle Actuator, the other microprocessor of the same microcomputer system calculating according to predetermined criteria, and only the breakdown signal derived from the comparison of corresponding values of voltage and current in successive half-waves of the DC filter voltage can be transmitted immediately to the higher-level microprocessor.
  • the higher-level microprocessor controlling the start-up and carrying of the voltage at the breakdown limit is kept free from the time-consuming breakdown detection and measured value processing, so that a relatively simple microcomputer system results despite the use of two processors (master-slave processor system).
  • the primary winding of a high-voltage transformer 3 is connected to an AC network U via a thyristor actuator 4.
  • the actual electrostatic filter 1 is connected to the secondary side of the high-voltage transformer 3 via a rectifier 2.
  • the amplitude of the pulsating DC filter voltage is dependent on the commands of the control unit 41, which in turn receives its control voltage U st from a microcomputer system 5 serving as a regulator.
  • the microcomputer system 5 consists essentially of a master processor 51 (master) and a slave processor 52 (slave); Both processors 51 and 52 operate on the same bus 57.
  • a memory 53 which is known from read / write memories (RAM) for data and read-only memories (ROM) for the operating system
  • a digital-analog -Converter 56 and an input-output stage 54 are connected for the transmission and reception of process signals.
  • a coupling element 58 also works on the bus, which can maintain the connection to a higher-level control computer 7 (see FIG. 2) via a bus system 71.
  • the input of data into the microcomputer system 5 is carried out via a connector 61 by means of a programming device 6.
  • processor 52 also has the task of detecting breakdowns in the filter. For this purpose, corresponding voltage or current values are compared with one another in successive half-waves and the breakdown signal is formed therefrom. This signal is immediately passed on to the control processor 51. The formation of this signal - and also other signals - is explained in more detail in connection with FIGS. 3 and 4.
  • FIG. 2 shows the use of such a control in the context of an electrostatic filter system consisting of several electrostatic filters A, B, C, through which the gas to be cleaned flows in the direction of arrow 8.
  • each filter A, B, C has its own control, i.e. assigned a microcomputer system 5.
  • Each of these microcomputer systems is connected via the coupling element 58 and a data bus 71 to a superordinate control computer 7 which can calculate superordinate optimization strategies or the like; e.g.
  • the separation efficiency can be detected by a dust loading measuring device 9 and the separation can be distributed to the individual filters in such a way that an optimal separation degree results with minimal energy expenditure.
  • the configuration mentioned above has the advantage that even if a microcomputer system 5 fails, the system can continue to be operated as such, since the other controls can continue to work individually. This also applies to the failure of the control processor 7, since even then the individual filters can still be regulated.
  • FIG. 3 shows the course of the pulsating DC filter voltage U F in kV as a function of the time t, with T denoting the period of the mains AC voltage.
  • the arithmetic mean value of the filter voltage is also of interest, for example for recording the filter characteristic, ie the filter current I F as a function of the filter voltage U F.
  • the sum ⁇ of all measured values and the number, for example 20 are transmitted to the control processor 51, which then calculates the mean value from this.
  • the mean value of the filter current is also of interest.
  • the individual measured values of the filter current I F for example 20, are added in the processor 52 during the duration of a half-wave.
  • the measured value sum and the number of mean values are also transmitted to the control processor 51, which can then carry out the mean value calculation.
  • the nominal current monitoring is also of interest; this requires the formation of the primary current effective value.
  • all individual measured values Jp 1 which are greater than the magnetizing current are added in the processor 52 during the duration of a half-wave.
  • the measured value sum, number of individual measured values and the peak value of the primary current are transmitted to the master processor 51, which can use this to calculate the effective value based on an approximate solution.
  • the output control voltage U St is actually present at the tax rate 41.
  • the individual measured values of the thyristor control voltage are also continuously called up and added in each half-wave.
  • the measured value sum and the number of measured values are likewise transmitted to the control processor 51, which carries out the mean value calculation. This must then again match the control voltage output via the digital-to-analog converter 56.
  • the peak values occurring in the 10 millisecond cycle and the arithmetic mean values of the filter voltage U F and the arithmetic mean values of the filter current I F are averaged over, for example, '1 second. These values can then be displayed on a numerical display, for example. If a control processor 7 is present, these second average values can also be averaged over a minute. These values can then be transferred to the control processor on request.
  • Another essential task of processor 52 is to detect a breakdown.
  • a method for detecting the breakdown on the high-voltage side can consist, for example, in that the voltage profiles of successive half-waves of the fluctuations in the voltage U F at the separator are continuously compared with one another and a predetermined deviation of mutually assigned half-wave measurement values serves as a criterion for a breakdown.
  • voltage comparisons of successive half-waves of the filter voltage are used, then the comparison of peak values of the primary current and additionally a minimum voltage monitoring.
  • Each of the individual voltage differences ⁇ U Fi is compared with a limit value, which is a certain percentage of the filter DC voltage.
  • the breakthrough signal is given when the difference is greater than the predetermined limit.
  • the primary current I p is rectified and the peak values of a half-wave and the following half-wave Î p (N), Î p (N + 1) are stored and with the corresponding values Î p (N + 2), Î p (N + 3) of the following network period compared.
  • the comparison of the assigned peak values of two network periods results in a certain Be breakthrough, the amount of which depends on the current strength, the breakthrough processing is also initiated.
  • the drop in the filter voltage U F below a predetermined target value is also considered.
  • control parameters e.g. Rise in the filter voltage and evaluation of the breakdowns per unit of time etc.
  • the control parameters e.g. Rise in the filter voltage and evaluation of the breakdowns per unit of time etc.
  • the programming device 6 depending on the filter conditions required. This means that the same control system can be used for a large number of different filters and systems.

Abstract

1. A process for operating an electrofiler circuit which is fed from an alternating voltage supply network by a control element (4) and a high-voltage rectifier (2) and wherein the control element (4) is controlled in dependence upon electrical operating filter data, characterized in that a cycle, which comprises a half-wave of the alternating network supply voltage, the electrical operating filter data is repeatedly sampled and stored by a microprocessor (52), and that at the end of the sampling cycle, the microprocessor (52) transfers the required current and voltage values to a surbonate further microprocessor (51) of the same micro-computer system, which microprocessor calculates the control signal of the control element (1) in accordance with predetermined criteria, and only immediately transmits to the subordinate microprocessor (51) the breakdown signal derived by comparison of corresponding values of voltage and current in successive half-waves of the direct filter voltage.

Description

Die Erfindung bezieht sich auf eine Steuerung für ein Elektrofilter, das über ein Stellglied und einen Hochspannungsgleichrichter aus einem Wechselspannungsnetz gespeist ist und bei dem das Stellglied abhängig von elektrischen Filterbetriebswerten aussteuerbar ist.The invention relates to a controller for an electrostatic filter, which is fed from an AC voltage network via an actuator and a high-voltage rectifier and in which the actuator can be controlled as a function of electrical filter operating values.

Mit diesem Oberbegriff wird auf Anordnungen Bezug genommen, wie sie beispielsweise aus der Siemens-Zeitschrift 1971 (Heft 9), Seiten 567 bis 572, insbesondere Bild 2 oder der DE-AS 11 48 977 bekannt sind.This generic term refers to arrangements such as are known, for example, from Siemens magazine 1971 (number 9), pages 567 to 572, in particular figure 2 or DE-AS 11 48 977.

Bei diesen bekannten Steuerungen werden unter anderem Filterstrom und Filterspannung erfaßt und abhängig von Durchschlägen so geführt, daß sich optimale Abscheideverhältnisse ergeben.In these known controls, filter current and filter voltage, among other things, are detected and guided depending on breakdowns in such a way that optimum separation conditions result.

Die bisher bekannten Steuerungen sind im allgemeinen mit Mitteln der Analogtechnik, also Verstärkern, Widerständen und Kondensatoren usw, aufgebaut. Im Zuge des Vordringens der Digitaltechnik wird es wünschenswert, auch hier für Steuerungszwecke den Mikroprozessor einzusetzen.The previously known controls are generally constructed using means of analog technology, that is to say amplifiers, resistors and capacitors, etc. As digital technology advances, it is desirable to use the microprocessor for control purposes.

Überträgt man nun Erfassung und Aufbereitung der Meßwerte sowie Weiterverarbeitung und Regelung einem Mikrocomputer mit einem Mikroprozessor, so ist dieser Rechner im allgemeinen durch die Erfassung und Aufbereitung der sich rasch ändernden Meßwerte so beschäftigt, daß für die eigentliche Regelung kaum mehr Zeit bleibt, es sei denn, es wird eine Beschränkung der Meßwerte durchgeführt oder ein aufwendiger Rechner benutzt. Die erste Alternative führt zu einem Verlust an Regelgenauigkeit oder Vielseitigkeit, die zweite Alternative zu erheblichem Kostenaufwand.If one transfers the acquisition and processing of the measured values as well as further processing and control to a microcomputer with a microprocessor, this computer is generally so busy with the acquisition and processing of the rapidly changing measured values that there is hardly any time left for the actual control, unless , the measured values are restricted or an expensive computer is used. The first alternative leads to a loss of control accuracy or Versatility, the second alternative at a considerable cost.

Hiervon ausgehend besteht die Aufgabe der vorliegenden Erfindung darin, eine universell einsetzbare und einfache Steuerung für Elektrofilter auf Mikroprozessorbasis zu schaffen, die hinsichtlich der Meßwerterfassung und Aufbereitung sehr vielseitig ist, aber gleichzeitig auch für übergeordnete Regelzwecke genügend Zeit zur Verfügung hat.Proceeding from this, the object of the present invention is to provide a universally applicable and simple control for electrostatic filters on a microprocessor basis, which is very versatile with regard to measured value acquisition and processing, but at the same time also has sufficient time available for superordinate control purposes.

Diese Aufgabe wird erfindungsgemäß dadurch gelöst, daß jeweils in einem maximal 1/2 Periode der Netzwechselspannung umfassenden Zyklus mehrfach die elektrischen Filterbetriebswerte durch einen Mikroprozessor abfragbar und speicherbar sind, der Mikroprozessor jeweils am Ende des Abtastzyklus die benötigten Strom- und Spannungswerte an einen das Steuersignal des Stellgliedes nach vorgegebenen Kriterien berechnenden, übergeordneten weiteren Mikroprozessor des gleichen Mikrocomputersystems übergibt und nur das aus dem Vergleich korrespondierender Werte von Spannung und Strom in aufeinanderfolgenden Halbwellen der Filtergleichspannung abgeleitete Durchschlagsignal sofort an den übergeordneten Mikroprozessor übertragbar ist.This object is achieved in that the electrical filter operating values can be queried and stored multiple times by a microprocessor in a cycle comprising a maximum of 1/2 period of the mains alternating voltage, the microprocessor in each case the required current and voltage values to the control signal of the at the end of the sampling cycle Actuator, the other microprocessor of the same microcomputer system calculating according to predetermined criteria, and only the breakdown signal derived from the comparison of corresponding values of voltage and current in successive half-waves of the DC filter voltage can be transmitted immediately to the higher-level microprocessor.

Auf diese Weise wird der das Hochfahren und Führen der Spannung an der Durchschlagsgrenze steuernde, übergeordnete Mikroprozessor von der zeitaufwendigen Durchschlagserfassung und Meßwertaufbereitung freigehalten, so daß sich trotz der Verwendung zweier Prozessoren (Master-Slave Prozessorsystem) ein verhältnismäßig einfaches Mikrocomputersystem ergibt.In this way, the higher-level microprocessor controlling the start-up and carrying of the voltage at the breakdown limit is kept free from the time-consuming breakdown detection and measured value processing, so that a relatively simple microcomputer system results despite the use of two processors (master-slave processor system).

Weitere vorteilhafte Ausgestaltungen der Steuerung sind in den kennzeichnenden Merkmalen der Unteransprüche beschrieben.Further advantageous refinements of the control are described in the characterizing features of the subclaims.

Anhand eines in der Zeichnung dargestellten Ausführungsbeispiels sei die Erfindung näher erläutert; es zeigen:

  • Figur 1 den Schaltungsaufbau der Steuerung,
  • Figur 2 eine aus mehreren Elektrofiltern bestehende Anlage mit individueller Steuerung je Filter,
  • Figur 3 einen beispielsweisen Verlauf der pulsierenden Filtergleichspannung und
  • Figur 4 einen beispielsweisen Verlauf des Primärstromes des Elektrofilters.
The invention will be explained in more detail with reference to an embodiment shown in the drawing; show it:
  • FIG. 1 shows the circuit structure of the control,
  • FIG. 2 shows a system consisting of several electrostatic filters with individual control for each filter,
  • Figure 3 shows an example of the course of the pulsating DC filter voltage
  • Figure 4 shows an example of the course of the primary current of the electrostatic filter.

Die Primärwicklung eines Hochspannungstransformators 3 ist über ein Thyristorstellglied 4 an ein Wechselspannungsnetz U angeschlossen. Auf der Sekundärseite des Hochspannungstransformators 3 ist über einen Gleichrichter 2 das eigentliche Elektrofilter 1 angeschlossen. Die Amplitude der pulsierenden Filtergleichspannung ist dabei von den Befehlen des Steuersatzes 41 abhängig, der seinerseits seine Steuerspannung Ust aus einem als Regler dienenden Mikrocomputersystem 5 erhält.The primary winding of a high-voltage transformer 3 is connected to an AC network U via a thyristor actuator 4. The actual electrostatic filter 1 is connected to the secondary side of the high-voltage transformer 3 via a rectifier 2. The amplitude of the pulsating DC filter voltage is dependent on the commands of the control unit 41, which in turn receives its control voltage U st from a microcomputer system 5 serving as a regulator.

Das Mikrocomputersystem 5 besteht im wesentlichen aus einem Leitprozessor 51 (Master) und einem Folgeprozessor 52 (Slave); beide Prozessoren 51 und 52 arbeiten auf den gleichen Bus 57. An diesen Bus 57 sind auch noch der in bekannter Weise aus Schreib-Lesespeichern (RAM) für Daten und Nur-Lesespeichern (ROM) für das Betriebssystem bestehende Speicher 53, ein Digital-Analog-Wandler 56 und eine Eingabe-Ausgabe-Stufe 54 zur Weitergabe und Empfang von Prozeß-Signalen angeschlossen. Ferner arbeitet auf den Bus auch noch ein Koppelglied 58, das die Verbindung zu einem übergeordneten Leitrechner 7 (vgl. Figur 2) über ein Bussystem 71 aufrechterhalten kann. Die Eingabe von Daten in das Mikrocomputersystem 5 wird über einen Anschlußstecker 61 mittels eines Programmiergerätes 6 vorgenommen. Die Anordnung arbeitet in der Weise, daß dem Primärstrom I p dem Filterstrom IF, der Filterspannung UF und der Steuerspannung Ust proportionale Werte über einen Analog-Digital-Wandler an den Prozessor 52 gelangen, dort aufbereitet werden und am Schluß ihres Abtastzyklus an den Leitprozessor 51 weitergegeben werden. Dieser berechnet dann nach vorgegebenen Kriterien die erforderlichen Stellbefehle für das Stellglied 4 und gibt diese über den Digital-Analog-Wandler 56 an den Steuersatz 41 aus. Zusätzlich hat der Prozessor 52 noch die Aufgabe, Durchschläge im Filter zu erkennen. Hierzu werden korrespondierende Spannungs- bzw. Stromwerte in aufeinanderfolgenden Halbwellen miteinander verglichen und hieraus das Durchschlägssignal gebildet. Dieses Signal wird sofort an den Leitprozessor 51 weitergegeben. Die Bildung dieses Signals - und auch anderer Signale - ist in Zusammenhang mit den Figuren 3 und 4 näher erläutert.The microcomputer system 5 consists essentially of a master processor 51 (master) and a slave processor 52 (slave); Both processors 51 and 52 operate on the same bus 57. On this bus 57 there is also a memory 53, which is known from read / write memories (RAM) for data and read-only memories (ROM) for the operating system, a digital-analog -Converter 56 and an input-output stage 54 are connected for the transmission and reception of process signals. Furthermore, a coupling element 58 also works on the bus, which can maintain the connection to a higher-level control computer 7 (see FIG. 2) via a bus system 71. The input of data into the microcomputer system 5 is carried out via a connector 61 by means of a programming device 6. The arrangement works in such a way that the primary current I p, the filter current I F , the filter voltage U F and the control Voltage U st proportional values reach the processor 52 via an analog-digital converter, are processed there and are passed on to the control processor 51 at the end of their sampling cycle. The latter then calculates the required control commands for the actuator 4 according to predetermined criteria and outputs them to the tax rate 41 via the digital-to-analog converter 56. In addition, processor 52 also has the task of detecting breakdowns in the filter. For this purpose, corresponding voltage or current values are compared with one another in successive half-waves and the breakdown signal is formed therefrom. This signal is immediately passed on to the control processor 51. The formation of this signal - and also other signals - is explained in more detail in connection with FIGS. 3 and 4.

Figur 2 zeigt den Einsatz einer derartigen Steuerung im Rahmen einer aus mehreren Elektrofiltern A, B, C bestehenden Elektrofilteranlage, die in Richtung des Pfeiles 8 von dem zu reinigenden Gas durchströmt wird. Wie ersichtlich, ist jedem Filter A, B, C eine eigene Steuerung, d.h. ein Mikrocomputersystem 5 zugeordnet. Jedes dieser Mikrocomputersysteme steht über das Koppelglied 58 und einen Datenbus 71 mit einem übergeordneten Leitrechner 7 in Verbindung, der übergeordnete Optimierungsstrategien oder dgl. berechnen kann; z.B. kann durch ein Staubbeladungsmeßgerät 9 die Abscheideleistung erfaßt und die Abscheidung so auf die einzelnen Filter verteilt werden, daß sich bei minimalen Energieaufwand ein optimaler Abscheidungsgrad ergibt. Die vorstehend erwähnte Konfiguration hat den Vorteil, daß auch bei Ausfall eines Mikrocomputersystems 5 die Anlage als solche weiterbetrieben werden kann, da die anderen Steuerungen individuell für sich weiterarbeiten können. Ebenso gilt dies für den Ausfall des Leitprozessors 7, da auch dann noch immer die einzelnen Filter regelbar sind.FIG. 2 shows the use of such a control in the context of an electrostatic filter system consisting of several electrostatic filters A, B, C, through which the gas to be cleaned flows in the direction of arrow 8. As can be seen, each filter A, B, C has its own control, i.e. assigned a microcomputer system 5. Each of these microcomputer systems is connected via the coupling element 58 and a data bus 71 to a superordinate control computer 7 which can calculate superordinate optimization strategies or the like; e.g. The separation efficiency can be detected by a dust loading measuring device 9 and the separation can be distributed to the individual filters in such a way that an optimal separation degree results with minimal energy expenditure. The configuration mentioned above has the advantage that even if a microcomputer system 5 fails, the system can continue to be operated as such, since the other controls can continue to work individually. This also applies to the failure of the control processor 7, since even then the individual filters can still be regulated.

Der vorstehend erwähnte modulare Aufbau führt außerdem zu Vorteilen bei Wartung und Nachrüstung von Elektrofilteranlagen und bietet ein Maximum an Störsicherheit. Figur 3 zeigt den Verlauf der pulsierenden Filtergleichspannung UF in kV in Abhängigkeit von der Zeit t, wobei mit T die Periodendauer der Netzwechselspannung bezeichnet ist. In jeder Halbperiode N, N+1 usw. der Netzwechselspannung U wird die Filterspannung UF 20x abgetastet, d.h. die Einzelwerte UFi(N) von i=o bis i = 20 vom Mikroprozessor 52 abgefragt und gespeichert. Tritt während der Halbwelle, d.h. im Abtastzyklus, kein Durchbruch auf, so wird in jeder Halbwelle N im Prozessor 52 der Scheitelwert Umax ermittelt und bei Beginn der nächsten Halbwelle N+1 an den Leitprozessor 51 übergeben. Dieser nimmt die automatische Anpassung der Filterspannung an die sich ändernden Betriebsverhältnisse des Elektrofilters vor. Außer dem für die Durchschlagsgrenze wichtigen Scheitelwert Umax ist auch der arithmetische Mittelwert der Filterspannung von Interesse, z.B. zur Aufnahme der Filtercharakteristik, d.h. des Filterstromes IF in Abhängigkeit von der Filterspannung UF. Hierzu wird am Ende jeder Spannungshalbwelle N die Summe Σ sämtlicher Meßwerte und die Anzahl, z.B. 20 an den Leitprozessor 51 übertragen, der hieraus dann den Mittelwert berechnet.The modular structure mentioned above also leads to advantages in the maintenance and retrofitting of electrostatic precipitator systems and offers maximum interference immunity. FIG. 3 shows the course of the pulsating DC filter voltage U F in kV as a function of the time t, with T denoting the period of the mains AC voltage. The filter voltage U F 20x is sampled in each half period N, N + 1 etc. of the AC line voltage U, ie the individual values U Fi (N) from i = o to i = 20 are queried and stored by the microprocessor 52. If no breakthrough occurs during the half-wave, ie in the sampling cycle, then the peak value U max is determined in the processor 52 in each half-wave N and transferred to the control processor 51 at the beginning of the next half-wave N + 1. This automatically adjusts the filter voltage to the changing operating conditions of the electrostatic filter. In addition to the peak value U max, which is important for the breakdown limit , the arithmetic mean value of the filter voltage is also of interest, for example for recording the filter characteristic, ie the filter current I F as a function of the filter voltage U F. For this purpose, at the end of each voltage half-wave N, the sum Σ of all measured values and the number, for example 20, are transmitted to the control processor 51, which then calculates the mean value from this.

Von Interesse ist auch der Mittelwert des Filterstromes. Hierzu werden im Prozessor 52 die Einzelmeßwerte des Filterstroms IF, z.B. 20, während der Dauer einer Halbwelle addiert. Bei Beginn der nächsten Halbwelle wird die Meßwertsumme und die Anzahl der Mittelwerte ebenfalls an den Leitprozessor 51 übertragen, der dann die Mittelwertberechnung ausführen kann.The mean value of the filter current is also of interest. For this purpose, the individual measured values of the filter current I F , for example 20, are added in the processor 52 during the duration of a half-wave. At the beginning of the next half-wave, the measured value sum and the number of mean values are also transmitted to the control processor 51, which can then carry out the mean value calculation.

Von Interesse ist auch die Nennstromüberwachung; hierzu ist die Bildung des Primärstromeffektivwertes notwendig. Hierzu werden im Prozessor 52 alle Einzelmeßwerte Jp1 die größer als der Magnetisierungsstrom sind, während der Dauer einer Halbwelle addiert. Bei Beginn der nächsten Halbwelle wird die Meßwertsumme, Anzahl der Einzelmeßwerte und der Scheitelwert des Primärstroms an den Master-Prozessor 51 übertragen, der hieraus nach einer Näherungslösung den Effektivwert berechnen kann.The nominal current monitoring is also of interest; this requires the formation of the primary current effective value. For this purpose, all individual measured values Jp 1 which are greater than the magnetizing current are added in the processor 52 during the duration of a half-wave. At the beginning of the next Most half-wave, the measured value sum, number of individual measured values and the peak value of the primary current are transmitted to the master processor 51, which can use this to calculate the effective value based on an approximate solution.

Von weiterem Interesse ist, ob die ausgegebene Steuerspannung USt auch tatsächlich am Steuersatz 41 vorliegt. Hierzu werden in jeder Halbwelle ebenfalls die Einzelmeßwerte der Thyristorsteuerspannung fortlaufend abgerufen und addiert. Bei Beginn der nächsten Halbwelle wird die Meßwertsumme und die Meßwertanzahl ebenfalls an den Leitprozessor 51 übertragen, der die Mittelwertberechnung ausführt. Diese muß dann wieder mit der über den Digital-Analog-Wandler 56 ausgegebenen Steuerspannung übereinstimmen.Of further interest is whether the output control voltage U St is actually present at the tax rate 41. For this purpose, the individual measured values of the thyristor control voltage are also continuously called up and added in each half-wave. At the beginning of the next half-wave, the measured value sum and the number of measured values are likewise transmitted to the control processor 51, which carries out the mean value calculation. This must then again match the control voltage output via the digital-to-analog converter 56.

Im Leitprozessor 51 selbst werden die im 10Millisekundenzyklus anfallenden Scheitelwerte und die arithmetischen Mittelwerte der Filterspannung UF sowie die arithmetischen Mittelwerte des Filterstroms IF über z.B. ' 1 Sekunde gemittelt. Diese Werte können dann z.B. an einer Ziffernanzeige angezeigt werden. Falls ein Leitprozessor 7 vorhanden ist, können diese Sekundenmittelwerte zusätzlich über eine Minute gemittelt werden. Diese Werte können dann auf Anforderung in den Leitprozessor übertragen werden.In the control processor 51 itself, the peak values occurring in the 10 millisecond cycle and the arithmetic mean values of the filter voltage U F and the arithmetic mean values of the filter current I F are averaged over, for example, '1 second. These values can then be displayed on a numerical display, for example. If a control processor 7 is present, these second average values can also be averaged over a minute. These values can then be transferred to the control processor on request.

Eine weitere wesentliche Aufgabe des Prozessors 52 besteht in der Erfassung eines Durchschlags.Another essential task of processor 52 is to detect a breakdown.

Ein Verfahren zum hochspannungsseitigen Erfassen des Durchschlags kann z.B. darin bestehen, daß jeweils die Spannungsverläufe aufeinanderfolgender Halbwellen der Schwankungen der Spannung UF am Abscheider miteinander fortlaufend verglichen werden und eine vorgegebene Abweichung einander zugeordneter Halbwellenmeßwerte als Kriterium für einen Durchschlag dient. Bei der hier vorliegenden Steuerung werden einmal Spannungsvergleiche aufeinanderfolgender Halbwellen der Filterspannung, dann der Vergleich von Scheitelwerten des Primärstromes und zusätzlich noch eine Mindestspannungsüberwachung verwendet. Hierzu werden, wie bereits ausgeführt, die Halbwellen der Filterspannung UF (vgl. Figur 3) z.B. 20x - Abtastungen i = 0,1,2... - pro Halbwelle N abgetastet, wobei der Halbwellenbeginn mit z.B. der Spannung UFO (N) durch das externe Signal Null-Durchgang der Netzspannung U mit der Periode T signalisiert wird. In dem dem Mikroprozessor 52 zugeordneten Speicherteil werden 20 dieser über die halbe Periode verteilte Einzelmeßwerte UFi (N) der Halbwelle (N) gespeichert. Anschließend werden 20 Einzelmeßwerte UFi (N+1) der nachfolgenden Halbwelle N+1 abgetastet und gespeichert, und zwar von gleicher Phasenlage wie die der vorhergehenden Halbwelle (N). Die Einzelmeßwerte gleicher Phasenlage aufeinanderfolgender Halbwellen werden miteinander verglichen und die Spannungsdifferenzen

Figure imgb0001
gebildet. Jede der Einzelspannungsdifferenzen ΔUFi wird mit einem Grenzwert verglichen, der ein bestimmter Prozentsatz der Filtergleichspannung ist. Das Durchbruchssignal wird gegeben, wenn die Differenz größer als der vorgegebene Grenzwert ist. Wie ersichtlich,liegt an der Stelle D in der Halbwelle N+1 ein Filterdurchschlag vor, da der hier vorliegende Spannungswert erheblich kleiner als der zugeordnete Spannungswert in der vorhergehenden Halbwelle N ist.A method for detecting the breakdown on the high-voltage side can consist, for example, in that the voltage profiles of successive half-waves of the fluctuations in the voltage U F at the separator are continuously compared with one another and a predetermined deviation of mutually assigned half-wave measurement values serves as a criterion for a breakdown. In front of here lying control, voltage comparisons of successive half-waves of the filter voltage are used, then the comparison of peak values of the primary current and additionally a minimum voltage monitoring. For this purpose, as already stated, the half-waves of the filter voltage U F (cf. FIG. 3), for example 20x samples i = 0.1.2 ... - are sampled per half-wave N, the half-wave beginning with, for example, the voltage U FO (N ) is signaled by the external signal zero crossing of the mains voltage U with the period T. In the memory part assigned to the microprocessor 52, 20 individual measured values U Fi (N) of the half-wave (N) distributed over half the period are stored. Subsequently, 20 individual measured values U Fi (N + 1) of the subsequent half-wave N + 1 are sampled and stored, in the same phase position as that of the previous half-wave (N). The individual measured values of the same phase position of successive half-waves are compared with one another and the voltage differences
Figure imgb0001
 educated. Each of the individual voltage differences ΔU Fi is compared with a limit value, which is a certain percentage of the filter DC voltage. The breakthrough signal is given when the difference is greater than the predetermined limit. As can be seen, there is a filter breakdown at point D in the half-wave N + 1, since the voltage value present here is considerably smaller than the assigned voltage value in the previous half-wave N.

Zur Überwachung des Stromkriteriums (vgl. Figur 4) wird der Primärstrom Ip gleichgerichtet und jeweils die Scheitelwerte einer Halbwelle und der folgenden Halbwelle Îp (N), Îp (N+1) gespeichert und mit den entsprechenden Werten Îp (N+2) , Îp (N+3) der folgenden Netzperiode verglichen. Ergibt der Vergleich der zugeordneten Scheitelwerte zweier Netzperioden eine über einen bestimmten Betrag hinausgehende Abweichung, deren Höhe von der vorliegenden Stromstärke abhängig gemacht ist, so wird ebenfalls die Durchbruchsverarbeitung angestoßen. Als zusätzliches Kriterium für den Durchschlag wird auch noch das Absinken der Filterspannung UF unter einen vorgegebenen Sollwert angesehen.To monitor the current criterion (cf. FIG. 4), the primary current I p is rectified and the peak values of a half-wave and the following half-wave Î p (N), Î p (N + 1) are stored and with the corresponding values Î p (N + 2), Î p (N + 3) of the following network period compared. The comparison of the assigned peak values of two network periods results in a certain Be breakthrough, the amount of which depends on the current strength, the breakthrough processing is also initiated. As an additional criterion for the breakdown, the drop in the filter voltage U F below a predetermined target value is also considered.

Von besonderem Interesse ist auch noch bei der vorliegenden Steuerung, daß die Regelparameter, wie z.B. Anstieg der Filterspannung und Bewertung der Durchschläge pro Zeiteinheit usw. je nach den geforderten Filterbedingungen von außen durch das Programmiergerät 6 in die Steuerung eingegeben werden können. Hierdurch kann die gleiche Steuerung für eine Vielzahl von unterschiedlichen Filtern und Anlagen verwendet werden.It is also of particular interest in the present control system that the control parameters, e.g. Rise in the filter voltage and evaluation of the breakdowns per unit of time etc. can be entered into the control system from the outside by the programming device 6, depending on the filter conditions required. This means that the same control system can be used for a large number of different filters and systems.

Claims (8)

1. Steuerung für ein Elektrofilter, das über ein Stellglied und einen Hochspannungsgleichrichter aus einem Wechselspannungsnetz gespeist ist und bei dem das Stellglied abhängig von elektrischen Filterbetriebswerten aussteuerbar ist, dadurch gekennzeichnet, daß jeweils in einem eine Halbwelle der Netzwechselspannung umfassenden Zyklus mehrfach die elektrischen Filterbetriebswerte durch einen Mikroprozessor abfragbar und speicherbar sind, der Mikroprozessor (52) jeweils am Ende des Abtastzyklus die benötigten Strom- und Spannungswerte an einen das Steuersignal des Stellgliedes (4) nach vorgegebenen Kriterien berechneten, übergeordneten weiteren Mikroprozessor (51) des gleichen Mikrocomputersystems (5) übergibt und nur das aus dem Vergleich korrespondierende Werte von Spannung und Strom in aufeinanderfolgenden Halbwellen der Filtergleichspannung abgeleitete Durchschlagssignal sofort an den übergeordneten Mikroprozessor (51) überträgt.1.Control for an electrostatic precipitator, which is fed via an actuator and a high-voltage rectifier from an AC voltage network and in which the actuator can be controlled as a function of electrical filter operating values, characterized in that the electrical filter operating values are repeated several times in a cycle comprising a half-wave of the mains alternating voltage Microprocessor can be queried and stored, the microprocessor (52) at the end of the sampling cycle transfers the required current and voltage values to a superordinate further microprocessor (51) of the same microcomputer system (5) calculated according to predetermined criteria and the control signal of the actuator (4) and only the breakdown signal derived from the comparison of the values of voltage and current in successive half-waves of the DC filter voltage is immediately transmitted to the higher-level microprocessor (51). 2. Steuerung nach Anspruch 1, dadurch gekennzeichnet, daß im Mikroprozessor (52) aus den abgetasteten Filterspannungswerten jeder Halbperiode der Scheitelwert ermittelbar ist und am Ende der Abtastperiode an den übergeordneten Prozessor (51) weitergebbar ist.2. Control according to claim 1, characterized in that the peak value can be determined in the microprocessor (52) from the sampled filter voltage values of each half period and can be passed on to the higher-level processor (51) at the end of the sampling period. 3. Steuerung nach Anspruch 1, dadurch gekennzeichnet, daß die Zahl und Summe der Spannungs- und Strommeßwerte vom Mikroprozessor (52) am Ende jedes Abtastzyklus an den übergeordneten Mikroprozessor (51) weitergebbar ist.3. Control according to claim 1, characterized in that the number and sum of the voltage and current measured values from the microprocessor (52) can be passed on to the higher-level microprocessor (51) at the end of each sampling cycle. 4. Steuerung nach Anspruch 1, dadurch gekennzeichnet, daß die Zahl und Summe der Steuerspannungswerte des Stellgliedes (4) in jedem Abtastzyklus ermittelbar und an den übergeordneten Mikroprozessor (51) übertragbar ist.4. Control according to claim 1, characterized in that the number and sum of the control voltage values of the actuator (4) in each Ab duty cycle can be determined and transmitted to the higher-level microprocessor (51). 5. Steuerung nach Anspruch 1, dadurch gekennzeichnet, daß im übergeordneten Prozessor (51) Langzeitmittelwerte von Filterstrom und Filterspannung für eine Anzeige errechenbar sind.5. Control according to claim 1, characterized in that long-term mean values of filter current and filter voltage can be calculated for a display in the higher-level processor (51). 6. Steuerung nach Anspruch 1, dadurch gekennzeichnet, daß die Abtastzyklen mit den Nulldurchgängen der Netzwechselspannung (U) synchronisiert sind.6. Control according to claim 1, characterized in that the sampling cycles are synchronized with the zero crossings of the AC line voltage (U). 7. Steuerung nach Anspruch 1, gekennzeichnet durch an den Mikrocomputerbus (57) angeschlossene Speicher für Filterparameter.7. Control according to claim 1, characterized by connected to the microcomputer bus (57) memory for filter parameters. 8. Steuerungen nach Anspruch 1, im Rahmen einer aus mehreren Filtern (A, B, C) bestehenden Elektrofilteranlage, gekennzeichnet durch eine den gleichartigen Steuerungen der Filter (A, B, C) überlagerten Leitrechner (7) zur Optimierung und Koordinierung der Filteranlage.8. Controls according to claim 1, in the context of a filter consisting of a plurality of filters (A, B, C), characterized by a control computer (7) superimposed on the similar controls of the filters (A, B, C) for optimizing and coordinating the filter system.
EP81101300A 1980-02-27 1981-02-23 Process for operating an electrofilter Expired EP0035209B1 (en)

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AT81101300T ATE8110T1 (en) 1980-02-27 1981-02-23 PROCEDURE FOR OPERATING AN ELECTRIC FILTER.

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DE19803007364 DE3007364A1 (en) 1980-02-27 1980-02-27 CONTROL FOR AN ELECTRIC FILTER

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0132659A1 (en) * 1983-07-20 1985-02-13 Siemens Aktiengesellschaft Regulating arrangement for an electrofilter
EP0499138A2 (en) * 1991-02-15 1992-08-19 Ente Nazionale Per L'energia Elettrica - (Enel) An assembly for controlling a voltage pulse feeder in a electrostatic precipitator
EP0569838A1 (en) * 1992-05-15 1993-11-18 Siemens Aktiengesellschaft Control process and control device for an electrofilter
EP0696365A1 (en) * 1993-04-02 1996-02-14 Belco Technologies Corporation System for controlling an electrostatic precipitator using digital signal processing
JP2003519004A (en) * 2000-01-05 2003-06-17 ザトーリウス アクチエン ゲゼルシャフト Crossflow filtration device and assembly

Families Citing this family (3)

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Publication number Priority date Publication date Assignee Title
DE3219664A1 (en) * 1982-05-26 1983-12-01 Metallgesellschaft Ag, 6000 Frankfurt Process for detecting breakdowns in an electrostatic filter
DE3219663A1 (en) * 1982-05-26 1983-12-01 Metallgesellschaft Ag, 6000 Frankfurt Process for detecting breakdowns in an electrostatic filter
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

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US3959715A (en) * 1972-11-16 1976-05-25 Dresser Industries, Inc. Automatic controller for electrostatic precipitator

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US3893828A (en) * 1973-06-11 1975-07-08 Wahlco Inc Electrostatic precipitator central monitor and control system

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US3959715A (en) * 1972-11-16 1976-05-25 Dresser Industries, Inc. Automatic controller for electrostatic precipitator

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0132659A1 (en) * 1983-07-20 1985-02-13 Siemens Aktiengesellschaft Regulating arrangement for an electrofilter
US4521228A (en) * 1983-07-20 1985-06-04 Siemens Aktiengesellschaft Control device for an electrostatic precipitator
EP0499138A2 (en) * 1991-02-15 1992-08-19 Ente Nazionale Per L'energia Elettrica - (Enel) An assembly for controlling a voltage pulse feeder in a electrostatic precipitator
EP0499138A3 (en) * 1991-02-15 1992-09-30 Ente Nazionale Per L'energia Elettrica - (Enel) An assembly for controlling a voltage pulse feeder in a electrostatic precipitator
EP0569838A1 (en) * 1992-05-15 1993-11-18 Siemens Aktiengesellschaft Control process and control device for an electrofilter
EP0696365A1 (en) * 1993-04-02 1996-02-14 Belco Technologies Corporation System for controlling an electrostatic precipitator using digital signal processing
EP0696365A4 (en) * 1993-04-02 1999-04-14 Belco Techn Corp System for controlling an electrostatic precipitator using digital signal processing
JP2003519004A (en) * 2000-01-05 2003-06-17 ザトーリウス アクチエン ゲゼルシャフト Crossflow filtration device and assembly
JP4817576B2 (en) * 2000-01-05 2011-11-16 ザトーリウス ステディム ビオテーク ゲーエムベーハー Cross-flow filtration device and assembly

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DE3007364A1 (en) 1981-09-10
ATE8110T1 (en) 1984-07-15
DE3164359D1 (en) 1984-08-02
EP0035209B1 (en) 1984-06-27

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