WO2012031924A1 - Procédé pour surveiller le vieillissement d'une substance organique et système de mesure pourvu d'un condensateur - Google Patents

Procédé pour surveiller le vieillissement d'une substance organique et système de mesure pourvu d'un condensateur Download PDF

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Publication number
WO2012031924A1
WO2012031924A1 PCT/EP2011/064789 EP2011064789W WO2012031924A1 WO 2012031924 A1 WO2012031924 A1 WO 2012031924A1 EP 2011064789 W EP2011064789 W EP 2011064789W WO 2012031924 A1 WO2012031924 A1 WO 2012031924A1
Authority
WO
WIPO (PCT)
Prior art keywords
capacitor
substance
voltage
oil
measurement
Prior art date
Application number
PCT/EP2011/064789
Other languages
German (de)
English (en)
Inventor
Jörg HASSEL
Arno Steckenborn
Oliver Theile
Original Assignee
Siemens Aktiengesellschaft
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 Siemens Aktiengesellschaft filed Critical Siemens Aktiengesellschaft
Publication of WO2012031924A1 publication Critical patent/WO2012031924A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/22—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance
    • G01N27/221—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance by investigating the dielectric properties
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/26—Oils; Viscous liquids; Paints; Inks
    • G01N33/28—Oils, i.e. hydrocarbon liquids
    • G01N33/2888—Lubricating oil characteristics, e.g. deterioration

Definitions

  • the invention relates to a method for monitoring the aging of an organic substance having dielectric properties, such as. B. transformer oil or bearing oil.
  • the invention relates to a measuring arrangement with a capaci tor, which has two capacitor electrodes.
  • Organic materials with dielectric properties are often used in the art, these changing their properties with time over the period of use.
  • the object of the invention is to provide a method for monitoring the aging of an organic substance having dielectric properties as well as a measuring arrangement for performing this method with which the monitoring at a reasonable technical complexity cost in regular ⁇ regular intervals or continuously can be carried out.
  • the voltage applied to the capacitor voltage can be changed over time.
  • the next step of the ent ⁇ standing by modulating the capacitance of the capacitor temporal profile of the displacement current I (t) is measured ⁇ ge. This results as a system response of the measuring system to the modulation of the charge on the capacitor. From the time course of the displacement current I (t) is then a determines time variation of the relative permittivity r ds / dt currency ⁇ end of the measurement.
  • this method of measurement makes use of the typical behavior of organic substances with dielectric properties (such as transformer oils) by measuring the dielectric charge shifts in the measuring capacitor (also known as the recharging effect in the capacitor) by a highly sensitive method.
  • This shift of charges is due to the movement of the charges in the electric field between the capacitor electrodes forming the measuring cell. Due to the charge shifts, the relative permittivity ⁇ ⁇ and, as a consequence, also the capacitance of the capacitor changes. This effect is also called dielectric relaxation.
  • the time profiles ds r / dt of the repeated measurements are compared with one another and are characterized by differences in the temporal progression are used as a measure of the aging of the substance.
  • the time lapse ds r / dt be compared with a lower and / or upper limit for the temporal courses of the relative permittivity and the difference to the upper limit and / or the lower limit value as a measure of the aging of the substance zoom is pulled ⁇ .
  • Ver ⁇ equal value must be determined as a function of the particular application, which can for example be electronically stored in a database. This can be done in the case of transformer oil for example, in the above genann ⁇ th way that oils of different ages used to be investigated.
  • the modulation of the charge on the capacitor during a measurement is carried out solely by the temporal variation of the voltage U (t) applied to the capacitor. This is advantageously a size that can be temporally changed only by electronic means.
  • the voltage U (t) applied to the capacitor is kept constant over time in sections, in particular a square-wave voltage, wherein in each case only the measured values of the time course ds r / dt of the relative performance be taken into account in such a section.
  • the voltage U (t) remains constant, in other words, so that the step response of the measuring system can be ge ⁇ measure.
  • characteristic curves which can be concluded on the dielectric Relaxationsverhal ⁇ th of the substance in question.
  • the capacitor area or the spacing of the capacitor electrodes is changed periodically, ie that the period of this periodic change is shorter by at least a factor of 2, in particular a factor of 10, than the sections of constant voltage on Capacitor.
  • This makes it possible to superimpose a plurality of influencing variables on one another for the measurement on the capacitor, the voltage applied to the capacitor being kept constant during the change of the distance of the capacitor electrodes or the capacitor surface. This advantageously makes it easier to evaluate the individual influencing factors of a change in the measurement result separately from one another.
  • the time constants of the dielectric relaxation in the range of a few ms up to the hour range can be determined.
  • the at capacitor anlie ⁇ constricting voltage U (t) is selected periodically over time, said measured values the time course ds r / dt of relative permittivity be taken into account in each case at the same locations of the periods. Comparing the so gewonne ⁇ NEN measured values, the influence of the voltage change is hereby eliminated, and it can be determined which is a multiple of the period of the applied voltage U (t) drifting of the reco ⁇ te in a period of time. That's it geous also possible to determine more accountablefakto ⁇ ren with different time constants in the measurement result.
  • the measurements are carried out at a specific temperature. In this case, it can be ruled out that a change in the dielectric properties of the organic substance due to temperature fluctuations is determined and is erroneously correlated with aging of the substance. The influence of temperature since ⁇ with are eliminated. If the substance is liquid, it is also advantageous if it flows continuously in the electric field of the capacitor. It can hereby be advantageous ver ⁇ prevents that by differences in concentration in the liquid substance a heterogeneous property profile is created which could not be used to uniquely identify age-related changes in properties. The continuous flow of the substance causes a circulation takes place in the Reser ⁇ voir of the substance in question, which ensure ⁇ at least largely uniform property profiles over the entire volume.
  • the interior of the transformer is defined by the space in which the transformer oil is enclosed. This includes mainly the installation space for the components to be cooled transformer, but also oil-filled areas of the transformer housing, can be implemented in de ⁇ nen certain functions.
  • Example ⁇ it may be a supply or circulation line for transformer oil in which a conveyor is provided as a pump. Such a line kom ⁇ municates with the installation space of the further transformer parts, wherein the transformer oil is removed at one point and fed back to another location.
  • the OF INVENTION ⁇ -making process according to the monitoring of the transformer oil can advantageously be closed at an early stage to a unzuläs ⁇ sig high aging-induced characteristic change of the transformer oil and measures such as replacement of the transformer oil or a regeneration will be initiated in good time before a fault in the transformer.
  • the transformer is in the context of the invention only an example of an oil circulation application. Therefore, the same arguments apply to other machines with oil circuits such as engines, turbines with sliding or oil-lubricated roller bearings and the like.
  • the OF INVENTION ⁇ to the invention the measuring arrangement with a capacitor in which a measuring cell is provided between the capacitor electrodes, which is accessible to a substance to be examined.
  • the measuring cell is therefore dictated by the geometry of the Kondensa ⁇ tors, which is located in the signal generated by the capacitor electrodes electric field.
  • the capacitor electrodes themselves can form wall parts of this measuring cell. But it is also possible that the capacitor electrodes are applied to any housing component, wherein the walls of this housing component must be permeable to the electric field.
  • the capacitor electrodes can be placed on the surface of anomme ⁇ sponding solid, thus forming a function of the geometry of the capacitor electrodes, the measuring cell to be examined solid.
  • the measuring arrangement according to the invention is simply made from a few components can be adapted very flexibly to the present application all.
  • one of the capacitor electrodes is formed as part of a micro-electro-mechanical system, where ⁇ in the micro-electro-mechanical system is on a Strombau ⁇ part and having a mechanically coupled to an actuator, movable diaphragm, the is displaceable by the actuator in front of the said capacitor electrode .
  • the actuator can move the shutter so that the capacitor electrode is released or shaded.
  • the diaphragm of a material which can at least from the electrical ⁇ 's field or not are heavier penetrated, as the medium otherwise located between the capacitor electrodes.
  • the structure of the micro-electro-mechanical system can be designed, for example, according to the aforementioned DE 10 2008 052 477 A1, which advantageously ent ⁇ a simple to manufacture component with a small footprint ent stands.
  • the micro-electro-mechanical system (hereinafter briefly referred to as MEMS) is suitable, for example, the clamping voltage ⁇ running U (t) to be determined.
  • the measuring cell is designed as part of a fluidic line for a liquid substance to be examined.
  • the measuring arrangement according to the invention is provided in the conduit in such a way that a measurement can be carried out on the substance to be examined while it flows through the conduit.
  • this measuring arrangement integrated into a pipe that is designed as part of an oil circuit of a machine. This makes it advantageous to carry out measurements on the oil in a simple manner, without the need for a removal of oil and external examination in the laboratory. Further details of the invention are described below with reference to schematic embodiments.
  • the same or corresponding Zeichnungsele ⁇ elements here are each provided with the same reference numerals and are explained only to the extent that there are differences between the individual figures. Show it :
  • FIG. 4 is a schematic circuit view of a machine with oil, in which the measurement assembly is installed in accordance with Fi gur ⁇ 2 and
  • Figures 5 and 6 waveforms as WUR created using embodiments of the method according to the invention ⁇ , once for glass as toomme ⁇ sponding material and once for an FR4 material as the organic material having dielectric properties.
  • a measuring device consists of a MEMS voltmeter 11, the structure of which is still described below.
  • a capacitor electrode 12a (see FIG. 3), not shown, is provided, which forms a capacitor 13 with a second capacitor electrode 12b.
  • the capacitor forms a measuring cell into which an organic substance 14 with dielectric properties in the form of a plate of FR4 material is introduced.
  • the MEMS voltmeter 11 has not further illustrates ⁇ asked connections, which make it possible to determine a shift Ver ⁇ current I (t) flowing at the pins sen when the capacitance of the capacitor is modulated. 13
  • An electronic circuit for determining the displacement current for example, the above-mentioned article by B.
  • FIG. 2 shows an alternative embodiment of the measuring device according to FIG.
  • This has a conduit 15 which is provided for receiving the substance to be examined 14 in liquid form.
  • This line 15 has a rectangular cross-section (not shown in detail), so that the MEMS voltmeter 11 with an associated support plate 16a and the capacitor electrode 12b with an associated Trä ⁇ gerplatte 16b just on the outer wall of the line 15 can be fastened ⁇ taken.
  • the capacitor plates 12a, 12b see also Figure 3
  • the capacitor area A (t) is predetermined.
  • the position of the capacitor plates 12a, 12b also determines their distance d.
  • the capacitor plates 12a, 12b are connected in the manner indicated to a voltage source 17 with which, for example, a square-wave voltage U (t) can be generated.
  • the MEMS voltmeter 11 according to FIGS. 1 and 2 (detail III) is shown schematically with its essential components.
  • the capacitor electrode 12a which are covered by a shutter 18 and released can.
  • This diaphragm 18 is therefore movable into and out of the measuring cell.
  • the diaphragm 18 is fixed with an elastic suspension 19 and connected to a mechanical coupling 20 with an actuator 21.
  • This consists of telescoping electrodes 22, which are available as an electrostatic drive for the diaphragm 18.
  • the components described are produced micromechanically in a carrier component 23, which in turn is fixed on the carrier plate 16a.
  • the actuator 21 is driven by a drive voltage, which is not shown in detail.
  • the time course of at ⁇ operating voltage is periodic, in particular, there is a square-wave voltage.
  • the period of the rectangular voltage is at most half, preferably one
  • a transformer 24 is shown as an example of a machine having an oil circuit. This is an outer view, wherein an oil circulation in the perception ⁇ ren of the transformer is indicated by a dot-dash line 25th This oil circuit also passes through a För ⁇ said power 26 with a pump 27. The bypass goes from the delivery line 26 and the line 15 from, in which the MEMS voltmeter is integrated. 11 At this point, a uniform volume flow in the conduit 15 can be ensured, so that the method according to the invention can be used. Likewise, according to the circumstances, the measuring system can also be integrated directly on the delivery line 26.
  • the measurement curve for a measurement setup is Darge ⁇ provides, in which instead of the inventive organic material 14, a glass plate is placed in the measuring cell shown in FIG. 1
  • the illustrated step function shows the course of the voltage U (t) applied to the capacitor electrodes as well as the course of the voltage determined by the displacement current I (t), which is output by the MEMS voltmeter (referred to as "signal (glass)").
  • the flow of the measured voltage and the applied voltage are the same, since a dielectric relaxation in this Frequency Ranges ⁇ is rich negligible in the glass sample.
  • a dashed line drawn ⁇ give (labeled "signal (FR4)").
  • a region 30 for the change of the relaxation curve and a region 31 for the change of the drift 29 are qualitatively indicated in FIG.
  • Such curves can be determined in particular for Tranformatoröl.
  • Factors that change the dielectric behavior of the transformer oil in particular can be the contamination of the transformer oil with water and a breaking of the molecules of the transformers ⁇ toröls. These effects inevitably have an effect on the characteristic relaxation curves with different time constants, so that criteria for a still permissible age-related change of these properties can be defined by defining ranges 30, 31 or comparable ranges.
  • A is the area of the capacitor electrodes and
  • d is the distance between the capacitor electrodes.
  • I (t) ⁇ -. U + .C + ⁇ . K f
  • U (t) is off-dU
  • the term - includes the dielectric relaxation. It changes
  • the ⁇ ser term which can be detected by the measurement.

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Pathology (AREA)
  • Immunology (AREA)
  • General Physics & Mathematics (AREA)
  • Physics & Mathematics (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Medicinal Chemistry (AREA)
  • Food Science & Technology (AREA)
  • General Chemical & Material Sciences (AREA)
  • Electrochemistry (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)

Abstract

L'invention concerne un procédé pour surveiller le vieillissement d'une substance organique ayant des propriétés diélectriques, comme par exemple de l'huile de transformateur ou également de l'huile ou de la graisse de palier. L'invention concerne également un système de mesure qui est pourvu d'un condensateur de mesure et qui est approprié à la mise en œuvre de ce procédé. Selon l'invention, la variation dans le temps du courant de déplacement I(t) est enregistrée de manière répétée par modulation de la charge sur le condensateur de mesure, un vieillissement de la substance étant déterminé du fait qu'un changement de la permittivité relative (28, 29) varie en fonction du vieillissement dans des régions (30, 31) de sorte qu'il soit possible de tirer des conclusions sur l'état de la substance subordonné au vieillissement. Le système de mesure peut avantageusement être réalisé comme un MEMS (microsystème électromécanique) ce qui permet une mise en œuvre du procédé à coût réduit.
PCT/EP2011/064789 2010-09-06 2011-08-29 Procédé pour surveiller le vieillissement d'une substance organique et système de mesure pourvu d'un condensateur WO2012031924A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102010044628.9 2010-09-06
DE102010044628 2010-09-06

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WO2012031924A1 true WO2012031924A1 (fr) 2012-03-15

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9841394B2 (en) 2015-11-16 2017-12-12 Pitco Frialator, Inc. System and method for sensing oil quality
US9861233B2 (en) 2014-06-30 2018-01-09 Pitco Frialator, Inc. System and method for sensing oil quality
US10436730B2 (en) 2015-12-21 2019-10-08 Pitco Frialator, Inc. System and method for sensing oil quality
CN116482216A (zh) * 2023-06-19 2023-07-25 国网安徽省电力有限公司电力科学研究院 一种变压器绝缘油老化程度的检测方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998050790A1 (fr) * 1997-05-07 1998-11-12 Lubrigard Limited Mesure electrique de la qualite d'une huile
US20070151806A1 (en) * 2004-05-07 2007-07-05 Boyle Frederick P Method for On-Line Monitoring of Condition of Non-Aqueous Fluids
WO2009124731A1 (fr) * 2008-04-10 2009-10-15 Robert Seuffer Gmbh & Co. Kg Procédé et dispositif de détermination d'une propriété d'un fluide diélectrique
DE102008052477A1 (de) 2008-10-20 2010-06-10 Siemens Aktiengesellschaft Als mikromechanisches System ausgebildeter Sensor für elektrische Felder

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998050790A1 (fr) * 1997-05-07 1998-11-12 Lubrigard Limited Mesure electrique de la qualite d'une huile
US20070151806A1 (en) * 2004-05-07 2007-07-05 Boyle Frederick P Method for On-Line Monitoring of Condition of Non-Aqueous Fluids
WO2009124731A1 (fr) * 2008-04-10 2009-10-15 Robert Seuffer Gmbh & Co. Kg Procédé et dispositif de détermination d'une propriété d'un fluide diélectrique
DE102008052477A1 (de) 2008-10-20 2010-06-10 Siemens Aktiengesellschaft Als mikromechanisches System ausgebildeter Sensor für elektrische Felder

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
B. BAHREY NI ET AL., JOURNAL OF MICROELECTROMECHANICAL SYSTEMS, vol. 17, no. 1, February 2008 (2008-02-01), pages 31 - 36
B. BAHREY NI ET AL., JOURNAL OF MICROELECTROMECHANICAL SYSTEMS, vol. 17, no. 1, February 2008 (2008-02-01), pages 31 - 36, XP002665461 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9861233B2 (en) 2014-06-30 2018-01-09 Pitco Frialator, Inc. System and method for sensing oil quality
US10178927B2 (en) 2014-06-30 2019-01-15 Pitco Frialator, Inc. System and method for sensing oil quality
US9841394B2 (en) 2015-11-16 2017-12-12 Pitco Frialator, Inc. System and method for sensing oil quality
US10436730B2 (en) 2015-12-21 2019-10-08 Pitco Frialator, Inc. System and method for sensing oil quality
CN116482216A (zh) * 2023-06-19 2023-07-25 国网安徽省电力有限公司电力科学研究院 一种变压器绝缘油老化程度的检测方法
CN116482216B (zh) * 2023-06-19 2023-08-25 国网安徽省电力有限公司电力科学研究院 一种变压器绝缘油老化程度的检测方法

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