WO2006128265A1 - Electronic gas relay - Google Patents

Electronic gas relay Download PDF

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Publication number
WO2006128265A1
WO2006128265A1 PCT/BR2006/000104 BR2006000104W WO2006128265A1 WO 2006128265 A1 WO2006128265 A1 WO 2006128265A1 BR 2006000104 W BR2006000104 W BR 2006000104W WO 2006128265 A1 WO2006128265 A1 WO 2006128265A1
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WO
WIPO (PCT)
Prior art keywords
insulating oil
gasses
relay
liquid medium
electronic
Prior art date
Application number
PCT/BR2006/000104
Other languages
French (fr)
Inventor
Junko Hiraoka
Alberto Moriyama
Original Assignee
Junko Hiraoka
Alberto Moriyama
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 Junko Hiraoka, Alberto Moriyama filed Critical Junko Hiraoka
Publication of WO2006128265A1 publication Critical patent/WO2006128265A1/en

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
    • G01F23/28—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring the variations of parameters of electromagnetic or acoustic waves applied directly to the liquid or fluent solid material
    • G01F23/296—Acoustic waves
    • G01F23/2962—Measuring transit time of reflected waves
    • G01F23/2963—Measuring transit time of reflected waves magnetostrictive
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
    • G01F23/26—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields
    • G01F23/263—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring variations of capacity or inductance of capacitors or inductors arising from the presence of liquid or fluent solid material in the electric or electromagnetic fields by measuring variations in capacitance of capacitors
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
    • G01F23/28—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring the variations of parameters of electromagnetic or acoustic waves applied directly to the liquid or fluent solid material
    • G01F23/284—Electromagnetic waves
    • G01F23/292—Light, e.g. infrared or ultraviolet
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
    • G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
    • G01F23/28—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring the variations of parameters of electromagnetic or acoustic waves applied directly to the liquid or fluent solid material
    • G01F23/296—Acoustic waves
    • G01F23/2962—Measuring transit time of reflected waves
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H33/00—High-tension or heavy-current switches with arc-extinguishing or arc-preventing means
    • H01H33/02—Details
    • H01H33/53—Cases; Reservoirs, tanks, piping or valves, for arc-extinguishing fluid; Accessories therefor, e.g. safety arrangements, pressure relief devices
    • H01H33/55—Oil reservoirs or tanks; Lowering means therefor
    • H01H33/555—Protective arrangements responsive to abnormal fluid pressure, liquid level or liquid displacement, e.g. Buchholz relays

Definitions

  • This invention relates to a gas relay with electronic devices that transmits continuous electric signals proportional to the volume of gasses retained in its interior, named ELECTRONIC GAS RELAY for electric power transformer immersed in insulating oil, composed of one tight metallic body manufactured with casting material or welded construction with laminated materials, comprising one chamber for capture and retention of gasses released from liquid medium, one electronic sensor device for identification of volumetric change of gasses and one electronic circuit module for signals transmitter that transmits electrical signals proportional to the volume of gasses captured inside the body.
  • ELECTRONIC GAS RELAY electric power transformer immersed in insulating oil
  • the electrical power transformer immersed in insulating oil with conservator tank uses insulating oil as a dielectric liquid medium and as a cooling agent of active parts.
  • the electrical power transformer is basically composed of: the active parts comprising the core, windings and solid insulation; the main oil tank or said transformer's body; and the expansion tank or said conservator tank; interconnected through one piping system, which make a tight mechanical system for containing the active parts and the insulating oil.
  • the pipe that connects the main tank to the conservator tank has a gas relay, universally known as Buchholz Gas Relay, that is basically an electric on-off type interrupter switch, which operates when a certain amount of gasses released from the insulating oil is detected.
  • gasses are captured and retained in internal part of the relay's body and whose function is to close the switch's electric contacts, which allows the supply electric current circulation in the protection and control circuit of the transformer's panel.
  • the gasses released from insulating oil which are captured and retained in inside part of relay's body they are originated from atmospheric air of the environment through breathing process of the conservator tank; or they are generated by degradation process of insulating oil itself due to its natural ageing; or they may also be generated due to high temperatures that may occur in insulating oil during electric failure situations in the active element due to dielectric loss of the solid or liquid insulation, poor contacts between electrical conductors, allowing partial discharges, voltaic arc or corona effect.
  • the ones said dissolved gasses are normally in solubilized state in insulating oil liquid medium, according to the "Gasses Dissolving Limit in Insulating Oil Bunsen Graph", that represents the maximum amount of gasses content that may be dissolved in the insulating oil for a given temperature at a constant pressure.
  • the gasses reach the super-saturation state in insulating oil, which occurs due to temperature or pressure decreasing, an amount of gasses may go from dissolved state to suspension state in insulating oil liquid medium, a phenomenon that may also occur when gasses generated by electrical failures do not have sufficient time to dissolve in insulating oil.
  • the gasses mass retained inside the space of relay's body may also be collected through an orifice located in upper part of the body, in order to constitute a sample for qualitative and quantitative analysis destination.
  • the qualitative identification of extracted gasses allows the achievement of state diagnosis of the electrical active parts due to characterization of such gasses origin: if they come from the atmospheric air; or they are produced by insulating oil's natural ageing process; or they are generated due to electrical failure in transformer. For instance, presence of acetylene gas in analyzed sample: this means that it occurred the phenomenon of voltaic arc in active parts, because this kind of phenomenon may occur only when there is a failure in transformer's dielectric medium.
  • the insulating oil and the solid insulation's quality control is performed with qualitative and quantitative analysis of contents of gasses dissolved in the liquid medium, that are normally performed by laboratories works in insulating oil samples periodically extracted from transformer.
  • the periodicity of insulating oil quality control analysis as general procedure is annual, but in certain cases this kind of procedure may be fatal to the transformer if any anomalous event is taking place in the active parts in the interval time between trials.
  • the gas relay installed in the connecting pipe from transformer's main tank to conservator tank permanently monitors the amount of gasses dissolved in insulating oil when they are released from liquid medium, in this way being an indispensable device for transformer's protection and control facilities. Therefore, the safety and reliability of transformer depend upon the good performance of gas relay.
  • the actual gas relay on-off electrical contacts elements are enacted by a set of mechanic devices comprising levers moved by a float that operates through the thrust action of insulating oil liquid medium which follows the interface surface level of gasses bed created by accumulation of gasses mass in the interior of relay's body.
  • ft is a device with purely mechanical work in unstable balance operation, it is subject to inappropriate operation caused by the wear and tear of the parts, by float and levers jamming due to insulating oil sludge incrustations, and by undue operation works caused by Shock waves propagation in the insulating oil liquid medium.
  • the device of this ELECTRONIC GAS RELAY invention as it makes use of electronic utilities in detection works of bed volumetric change of captured gasses in the relay's body, it is immune for the wear and tear and jamming, it is also undue operation free, therefore it adds greater reliability to transformer control and protecting operations.
  • the Buchholz Gas Relay is a device that was introduced for protection and control of electrical power transformer immersed in insulating oil in 1920 ! s, and has improved very little up to present days. As it was seen, it basically comprises one floating buoy, one set of levers and one on-off micro switch with electrical contacts.
  • Buchholz Gas Relay Complete informations about Buchholz Gas Relay may be found in specialized technical literatures where it may be found as trafoscope, Gas Relay or Buchholz Type Gas Relay.
  • Moving Conductive Liquid which deals with an actuator to enact mechanisms of electric contacts, replacing floating buoys, is not, in any aspects, similar to the object of this invention.
  • Nonbuming Transformer which deals with a transformer that has a device for disposing the gasses generated by the insulating oil upon electrical failures, said device being enacted by a float, and one unit for the de-gasification of the insulating oil, is not, in any aspects, similar to this invention.
  • the electric contacts closing action that characterizes the gas relay operation is caused by the movement of a levers set, which is moved by the buoyancy float that works in the interface level surface between insulating oil liquid medium and gaseous medium of gasses mass released from insulating oil, creating a gas bed inside the relay's body.
  • the insulating oil that initially fills total internal volume of relay's body changes the occupied space inside the body with captured and retained gasses mass released from insulating oil, until the creation of a certain gas bed thick enough to promote the float actuation and movement of levers set, which enact electric on-off micro switch.
  • the mechanic device that moves the electric contacts is a set of fine precision mechanic parts, similar to those produced with high precision clock manufacture technique, comprising a set of articulated arms in unstable balance working.
  • the internal environment of gas relay's body comprising the insulating oil is hostile to operation of such mechanic device, due to formation of sludge what causes jamming of articulated parts by incrustation, which requires constant cleaning and maintenance services.
  • the parts of the mechanic device, as well, are subject to wear and tear due to the friction in the supported points. And, if the electric on-off switch is mercury type, the glass ampoule may break, and then, mercury may contaminate insulating oil, causing serious losses.
  • the current Buchholz Gas Relay is also vulnerable to said false undue operation.
  • the mechanic device is in unstable balance, it is sensible to pressure waves that transit in the insulating oil medium when short-circuits external to the transformer occur, and therefore provoking actuation of relay.
  • electric cables of energy distribution networks touch each other, due to wind action or due to branches of the trees movement, they create a short-circuit external to transformer, which responds with abnormal behavior of active parts, generating pressure waves that propagate through insulating oil liquid medium inside transformer.
  • the high number of occurrences for this type of event leads the transformer users to keep the relay turned off; i.e., "jumped", out of operation.
  • the anomalous state is not detected and it results in a catastrophe for the transformer what may result in explosion and fire.
  • This electronic gas relay invention is a new device with updated technology for electric power transformer immersed in insulating oil, which allows improvement to techniques of protection and control to transformer, because it makes available continuous electric signals that are proportional to volumetric variation of the bed of gasses released from insulating oil. It is also a definitive solution to solve inconveniences caused by current Buchholz Gas Relay. BRIEF DESCRIPTION OF DRAWINGS
  • Figure 1A is a scheme for electronic gas relay installation in connecting pipe between main tank and conservator tank for option "in line installation way”.
  • Figure 1B is a scheme for electronic gas relay installation in connecting pipe between main tank and conservator tank for option "in high point installation way”.
  • Figure 2 is a drawing of electronic gas relay with constructive design for installation in connecting pipe between main tank and conservator tank for option "in line installation way", that shows a magnet-restrictive electronic sensor device only for presentation purposes.
  • Figure 3 is a drawing of electronic gas relay with constructive design for installation in the connecting pipe between main tank and conservator tank for option "in high point installation way", that shows a capacitive electronic sensor device only for presentation purposes.
  • Figures 4A, 4B and 4C are composed by pictures that show the gas bed thickness evolution sequences of gasses released from insulating oil captured and retained in a capacitive type electronic gas relay body with the connection end for option "in high point installation way” in connecting pipe
  • Figures 5A, 5B and 5C are composed by pictures that show the gas bed thickness evolution sequence of gasses released from the insulating oil captured and retained in a magnetic-restrictive type electronic gas relay body with the connection end for option "in high point installation way” in connecting pipe.
  • Figures 6A, 6B and 6C are composed by pictures that show the gas bed thickness evolution sequences of gasses released from the insulating oil captured and retained in a ultrasonic type electronic gas relay body with the connection end for option "in high point installation way" in connecting pipe.
  • Figures 7A, 7B and 7C are composed by pictures that show the gas bed thickness evolution sequences of gasses released from the insulating oil captured and retained in a optical refraction of infrared radiation beam type electronic gas relay body with the connection end for option "in high point installation way" in connecting pipe.
  • Figures 8A, 8B and 8C are composed by pictures that show the gas bed thickness evolution sequences of gasses released from the insulating oil captured and retained in a optical reflection of laser ray radiation beam type electronic gas relay body with the connection end for option "in high point installation way" in connecting pipe.
  • the electronic gas relay is a device for protection of electric power transformer immersed in insulating oil to be installed as option "in line installation way” in connecting pipe 5 of main tank 3 to conservator tank 4 according to Figure 1A 1 or to be installed as option "in high point installation way” in connecting pipe 5 according to Figure 1B.
  • the active parts 1, a primordial electrical component of transformer, is immersed in insulating oil liquid medium 2.
  • the main tank 3 is connected to conservator tank 4, through connecting pipe 5, which is the communication way of insulating oil between such tanks.
  • the constructive design of electronic gas relay 6 for option "in line installation way” in connecting pipe 5 is shown in the drawing of Figure 2.
  • the electronic gas relay 6, object of this invention has a tight metallic body 11 manufactured with casting material or welded construction with laminated materials, to contain the insulating oil liquid medium 2 and the gasses 10 released from the insulating oil that are separated by an interface level surface 9.
  • the electronic gas relay 6 also comprises: the installation connection ends 18; the sight glass 16; the baffle 17 that promotes deviation of oil flow coarse inside the body 11 and creates a favorable condition for releasing gasses that are in suspension state in insulating oil liquid medium 2; the cover 12 that works as a chamber for capture, retention and detection by an electronic sensor device of the gas bed 10 created with the gasses released from insulating oil; a gas purging orifice 15; the electronic sensor device appropriate for each operation principle, represented in this Figure 2 by the electronic magnet-restrictive sensor device comprising the float 13a that has a magnet in its interior, the stem 13b that contains internally an electrical conductor wire and the electronic circuit module for signal transmitter 14.
  • the constructive design of electronic gas relay 7 for option "in high point installation way" in the connecting pipe 5 is shown in the drawing of Figure 3.
  • the electronic gas relay 7, object of this invention has a tight metallic body 21 manufactured with casting material or welded construction with laminated materials, to contain the insulating oil liquid medium 2 that is separated by an interface level surface 9 from the gasses 10 released from the insulating oil.
  • the electronic gas relay 7 is also constituted by: the installation connection end 27 for installing with a block valve 8 attached in connecting pipe 5; the gasses purging orifice 25; the sight glass 26; the cover 22 to close the body for retaining released gasses 10 and to attach the electronic sensor device with electronic circuit module for signal transmitter. This electronic sensor device shall be made accordingly for each operation modal type.
  • Figure 3 shows the capacitive electronic sensor device with capacitive stem 23 and electronic circuit module for signal transmitter 24. Only for simplifying the comprehension of this descriptive text, the following one relates to an electronic gas relay 7 with constructive design for option "in high point installation way” in connecting pipe 5. Therefore the description text is the same for both alternatives: to the electronic gas relay 6 for option “in line installation way” and to the electronic gas relay 7 for option “in high point installation way” in connecting pipe 5.
  • the electronic gas relay 7 is installed in the connecting pipe 5 at top height elevation position (relative to connecting pipe) below the bottom height elevation position of conservator tank 4.
  • the body 21 which is initially fulfilled with insulating oil liquid medium 2 , due to its installation arrangement and its geometric form, creates favorable condition to work as a trap for capturing the gasses 10 that are released from insulating oil liquid medium 2.
  • the gasses dissolved in insulating oil liquid medium 2 when they reach the supersatu ration state, or the gasses generated in electric failures that have not had time enough to solubilize in insulating oil liquid medium 2, become in suspension state in insulating oil liquid medium 2, and go to agglutinate and create gas micro bubbles.
  • the action of thrust force, by Principle of Archimedes, on gasses micro bubbles in suspension state in insulating oil liquid medium 2, causes the travel of such gas micro bubbles towards the upper part of main tank 3, and then, to conservator tank 4 through connecting pipe 5, wherein they are captured inside the body 21 of electronic gas relay 7, continually forming one crescent size bubble, which increases in volume with the capture of other new gas micro bubbles from gasses 10 released from the insulating oil liquid medium 2.
  • the continuous increase in volume of gas bubbles retained internally in upper part of body 21 create a gas bed 10 released from insulating oil, whose thickness also increases with incoming of other new gasses micro bubbles, and the body 21 will be fulfilled with gasses.
  • This dynamic way of creation of gas bed characterizes the body as a favorable environment for release of gasses in suspension state in insulating oil liquid medium 2 and behaves as a chamber for capture and retention of gasses, and allows the actuation of electronic sensor device for the volumetric identification of gasses retained in body 21.
  • the electronic sensor device identifies the bed volumetric change of gasses 10 released from insulating oil that are retained in the body 21 and may operate according to distinct operation mode such as: the capacitance change for capacitive mode; the time needed to detect a sound produced by Wiedemann Effect for magnet- restrictive mode; the time needed for wave return for ultrasonic mode; the deviation measure of refracted beam for optical refraction of a infrared radiation beam mode; or the deviation measure of reflected beam for optical reflection of a laser ray beam mode.
  • distinct operation mode such as: the capacitance change for capacitive mode; the time needed to detect a sound produced by Wiedemann Effect for magnet- restrictive mode; the time needed for wave return for ultrasonic mode; the deviation measure of refracted beam for optical refraction of a infrared radiation beam mode; or the deviation measure of reflected beam for optical reflection of a laser ray beam mode.
  • the capacitive electronic sensor device of electronic gas relay 7, with an electronic circuit module and signal transmitter 4, identifies the bed volumetric change of gasses 10 released from insulating oil and retained in the body 21, through electric capacitance change of capacitor composed by body 21 itself and by a capacitive stem 23, in which electric capacitance value is proportional to dielectric value of presented insulating oil liquid medium 2, which changes due to volume changing of insulating oil liquid medium 2 as consequence of bed volumetric change of gasses 10 released from insulating oil and retained in the body 21.
  • the internal space of body 21 is entirely occupied by insulating oil liquid medium 2; after that, the space is also occupied by the bed of released gasses 10 that is created in upper part of body 21 , according to Figure 4B, and that is separated from the insulating oil by interface level surface 9; until, according to Figure 4C, the bed of released gasses 10 occupies the maximum volume within the internal space of body 21.
  • the magnet-restrictive electronic sensor device of electronic gas relay 7, with an electronic circuit module and signal transmitter 4, identifies the bed volumetric change of gasses 10 released from the insulating oil and retained inside the body 21 by position of float that has an internal magnet 13b which follows the surface position of interface level surface 9.
  • the float with a central guide hole, allows the passing of a stem 13a, which contains internally an electric conductor wire for propagation of electrical pulse, which is emitted by electronic circuit module 14. Whether the electrical pulse, when traveling through conductor wire, interacts with the magnetic field of the magnet mounted inside the float 13b, the conductor wire allows a torsion that produces a click sound called Wiedemann Effect.
  • the click sound wave travels through conductor wire to reach the electronic circuit module 14, where it is collected and the time difference between the time from emission of electric pulse and the time for collecting click sound wave determines the bed thickness of gasses 10 released from insulating oil liquid medium and retained in body 21 , which is separated from insulating oil by an interface level surface 9. And, finally, according to Figure 5C, released gasses 10 fill the maximum volume within internal spaces of body 21.
  • the ultrasonic electronic sensor device of electronic gas relay 7, identifies the bed volumetric change of gasses 10 released from insulating oil and retained in body 21.
  • the electronic sensor device comprising an ultrasound wave emitting / receiving source 31 said ultrasonic transducer and an electronic circuit module and signal transmitter 32, detects the bed volumetric change of gasses 10 contained in body 21 through the bed thickness change, which is identified by response time difference between the ultrasound wave emission and reception times.
  • the ultrasound wave travels through gas medium of gasses bed and reaches the interface level surface 9 of gas-liquid phases; it reflects on the liquid surface and it is collected by electronic sensor device 31 mounted at upper part inside body 21. So it is established the co-relation between emission and reception times difference of ultrasound wave and the bed thickness of gasses retained in body 21.
  • the internal space of body 21 is entirely filled by insulating oil liquid medium 2; the space is then beginning to be filled with gasses, as shown in Figure 6B, also the bed is created at internal upper part in body 21 with released gasses 10 which is separated from the insulating oil liquid medium by an interface level surface 9; until, finally, according to Figure 6C, the bed of released gasses 10 occupies the maximum volume within the internal space of body 21.
  • the optical reflection electronic sensor device of electronic gas relay 7, comprising a laser ray beam emitting source 51 mounted in upper part of body 21 , a photocells set 52 sensible to laser ray beam and an electronic circuit module and signal transmitter 53, identifies the bed volumetric change of gasses retained in body 21 through the change of incidence point of the reflected laser ray beam on the photocells set, which is reflected by interface level surface 9, in a certain off-set angle relative to interface level surface 9 normal axis. In this way, when the laser ray beam, traveling through gaseous medium 10, reaches the interface level surface 9, it will reflect and fall upon photocells set at a point that changes according to bed thickness of gasses 10 retained inside body 21.
  • the great merit of this invention is to change a mechanical movable set composed of levers and other mobile parts by electronic fixed set composed of electronic sensor devices, electronic circuit modules and signal transmitters, except for floats in case of electronic magnet-restrictive sensor device.
  • This electronic fixed set application for detecting and identifying the bed volumetric change of gasses retained inside body 21 is an adapted form with inverted function of technologies already established and widely used in liquid level control process.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Thermal Sciences (AREA)
  • Fluid Mechanics (AREA)
  • General Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Housings And Mounting Of Transformers (AREA)
  • Testing Relating To Insulation (AREA)

Abstract

Electronic Gas Relay for electrical power transformer immersed in insulating oil is a device for capture and retention of gasses released from insulating oil liquid medium, for operating an electronic circuit module and an electric signal transmitter by an electronic sensor device; and for transmitting the electric signals proportional to the bed volumetric change of such gasses released from insulating oil liquid medium, which are captured and retained inside its body made of metallic material. The electronic gas relay has the following operation modals: the capacitance change for capacitive mode, the time needed to detect a sound produced by Wiedemann Effect for magnet-restrictive mode, the time needed for wave return for ultrasonic mode, the deviation measure of refracted beam for optical refraction of a infrared radiation beam mode, or the deviation measure of reflected beam for optical reflection of a laser ray beam mode.

Description

"ELECTRONIC GAS RELAY"
TECHNICAL FIELD
This invention relates to a gas relay with electronic devices that transmits continuous electric signals proportional to the volume of gasses retained in its interior, named ELECTRONIC GAS RELAY for electric power transformer immersed in insulating oil, composed of one tight metallic body manufactured with casting material or welded construction with laminated materials, comprising one chamber for capture and retention of gasses released from liquid medium, one electronic sensor device for identification of volumetric change of gasses and one electronic circuit module for signals transmitter that transmits electrical signals proportional to the volume of gasses captured inside the body. BACKGROUND ART
The electrical power transformer immersed in insulating oil with conservator tank uses insulating oil as a dielectric liquid medium and as a cooling agent of active parts. The electrical power transformer is basically composed of: the active parts comprising the core, windings and solid insulation; the main oil tank or said transformer's body; and the expansion tank or said conservator tank; interconnected through one piping system, which make a tight mechanical system for containing the active parts and the insulating oil. The pipe that connects the main tank to the conservator tank has a gas relay, universally known as Buchholz Gas Relay, that is basically an electric on-off type interrupter switch, which operates when a certain amount of gasses released from the insulating oil is detected. These gasses are captured and retained in internal part of the relay's body and whose function is to close the switch's electric contacts, which allows the supply electric current circulation in the protection and control circuit of the transformer's panel. The gasses released from insulating oil which are captured and retained in inside part of relay's body: they are originated from atmospheric air of the environment through breathing process of the conservator tank; or they are generated by degradation process of insulating oil itself due to its natural ageing; or they may also be generated due to high temperatures that may occur in insulating oil during electric failure situations in the active element due to dielectric loss of the solid or liquid insulation, poor contacts between electrical conductors, allowing partial discharges, voltaic arc or corona effect.
The ones said dissolved gasses are normally in solubilized state in insulating oil liquid medium, according to the "Gasses Dissolving Limit in Insulating Oil Bunsen Graph", that represents the maximum amount of gasses content that may be dissolved in the insulating oil for a given temperature at a constant pressure. When the gasses reach the super-saturation state in insulating oil, which occurs due to temperature or pressure decreasing, an amount of gasses may go from dissolved state to suspension state in insulating oil liquid medium, a phenomenon that may also occur when gasses generated by electrical failures do not have sufficient time to dissolve in insulating oil.
The mass of gasses in suspension state in the insulating oil liquid medium, under action of thrust force, tends to move in direction to the highest point of insulating oil liquid medium of transformer. Thus, when the gasses in suspension state in the liquid medium move from main tank, where they are generated due to electrical failures, towards conservator tank, located in a more elevated position relative to main tank itself, through connecting pipe, these gasses are released from the insulating oil liquid medium, whether they find a favorable medium. Such gasses are captured and retained in the internal space of the relay's body that works as a medium phase separation trap of gasses in suspension state in insulating oil liquid medium. The relay's body, when filled internally with a certain volume of gasses, allows the work of mechanic devices that close the switch contacts for electric current circulation in the circuit of protection and control of transformer's panel.
And, the gasses mass retained inside the space of relay's body may also be collected through an orifice located in upper part of the body, in order to constitute a sample for qualitative and quantitative analysis destination. The qualitative identification of extracted gasses allows the achievement of state diagnosis of the electrical active parts due to characterization of such gasses origin: if they come from the atmospheric air; or they are produced by insulating oil's natural ageing process; or they are generated due to electrical failure in transformer. For instance, presence of acetylene gas in analyzed sample: this means that it occurred the phenomenon of voltaic arc in active parts, because this kind of phenomenon may occur only when there is a failure in transformer's dielectric medium.
The insulating oil and the solid insulation's quality control is performed with qualitative and quantitative analysis of contents of gasses dissolved in the liquid medium, that are normally performed by laboratories works in insulating oil samples periodically extracted from transformer. The periodicity of insulating oil quality control analysis as general procedure is annual, but in certain cases this kind of procedure may be fatal to the transformer if any anomalous event is taking place in the active parts in the interval time between trials. Thus, the gas relay installed in the connecting pipe from transformer's main tank to conservator tank, permanently monitors the amount of gasses dissolved in insulating oil when they are released from liquid medium, in this way being an indispensable device for transformer's protection and control facilities. Therefore, the safety and reliability of transformer depend upon the good performance of gas relay. The actual gas relay on-off electrical contacts elements are enacted by a set of mechanic devices comprising levers moved by a float that operates through the thrust action of insulating oil liquid medium which follows the interface surface level of gasses bed created by accumulation of gasses mass in the interior of relay's body. And, as ft is a device with purely mechanical work in unstable balance operation, it is subject to inappropriate operation caused by the wear and tear of the parts, by float and levers jamming due to insulating oil sludge incrustations, and by undue operation works caused by Shock waves propagation in the insulating oil liquid medium.
The device of this ELECTRONIC GAS RELAY invention, as it makes use of electronic utilities in detection works of bed volumetric change of captured gasses in the relay's body, it is immune for the wear and tear and jamming, it is also undue operation free, therefore it adds greater reliability to transformer control and protecting operations.
The Buchholz Gas Relay is a device that was introduced for protection and control of electrical power transformer immersed in insulating oil in 1920!s, and has improved very little up to present days. As it was seen, it basically comprises one floating buoy, one set of levers and one on-off micro switch with electrical contacts.
Complete informations about Buchholz Gas Relay may be found in specialized technical literatures where it may be found as trafoscope, Gas Relay or Buchholz Type Gas Relay.
The Brazilian publication "Manutencao de Transformadores em Lϊquido Isolante, Milan Milasch, 1984, Editora Edgar Blϋcher Ltda." [Maintenance of Transformers
Immersed in Dielectric Liquid] on pages 237 to 242 and catalogs of transformers and accessories manufacturers provide broad and adequate information to state-of-art of gas relay, what proves that it has been little improved since it was introduced in the market.
The researches in databanks of INPI [National Intellectual Property Institute - Brazil] and in the international patent's bases show that there are no novelties as to the modal of volumetric detection of gasses mass captured in the relay's body, as:
The patent WO 03/098763 of Williams, John, Owen (AU/ AU), "Modified Buchholz Relay For Continuous Monitoring Of Gas Generated by Transformer Internal Faults", which deals with improvements introduced in the current Buchholz type gas relay, is not, in any aspect, similar to the object of this invention.
The patent WO 2003/ 011422 of Altmann, Josef (CZ/CZ), "The Device for
Reducing The Gas And Water Contamination Of Transformer Oil Filling", which deals with a stabilization tank with one bed of stratification of the dense phases of the bottom of the conservator tank and hot phase of the bottom of the main tank which, with the aid of one under installed Buchholz Gas Relay, obtains the elimination of the gasses dissolved in the hot phase oil. The applied Buchholz Gas Relay does not present novelties such as this invention, and, is not, in any aspects, similar to this invention. The patent WO 2004/ 046019 of Montanya Silvestre, Josep (ES/ ES),
"Miniature Relay And Corresponding Uses Thereof, which deals with one principle of one capacitive cell in which the sensor element (pos. 7) is a mobile part, which does not occur with the object of this invention.
The patent USP-6,072,398 of Hayes; James, Appl. No. 294877, "Automatic Gas Detection System", which deals with one sensor for the carbon monoxyde gas to be employed in the monitoring of the internal space occupied by car passengers, nor similar, in any aspects, to the object of this invention.
The patent USP-4,561 ,464 of Frantz; Virgil L. (Salem, VA), "Relay Valve", which deals with one valve to be installed in a gas piping system, is not, in any aspects, similar to the object of this invention.
The patent USP-4,419,650 of John; Frank T. (Williamsville, NY), "Liquid
Contact Relay Incorporating Gas-Containing Finely Reticular Solid Motor Element for
Moving Conductive Liquid", which deals with an actuator to enact mechanisms of electric contacts, replacing floating buoys, is not, in any aspects, similar to the object of this invention.
The patent USP-4,263,938 of Frantz; Virgil L. (Salem, VA), "Relay Valve for
Fluid Actuators", which deals with one valve for controlling a hydraulic actuator of operation of piping systems valves, is not, in any aspects, similar to the object of this invention. The patent USP-4, 168,480 of De Lucia; Victor E. (Santa Monica, CA),
"Relay Assembly", which deals with an electric switch for use in electric systems that use the SF6 (sulphur hexafluoride) as a dielectric medium, is not, in any aspects, similar to the object of this invention. The patent USP-4,001,644 of Lingenfelter, et al., Sharon, PA, "Sudden Pressure Relay Having Seismic Protection", which deals with one relay enacted by a floater to monitor perturbations that may occur on the surface of the dielectric liquid in electrical equipment with dielectric fluid, such as the sealed transformers, not the ones immersed in insulating liquid that have a conservator tank, is not, in any aspects, similar to the object of this invention.
The patent GB557957 of BRITISH THOMSON HOUSTON CO LTD, "Improvements in and relating to fluid dielectric systems for electric apparatus", which deals with a system for the de-gasification of electric equipment immersed in insulating oil, such as the transformer, is not, in any aspects, similar to the object of this invention.
The patent GB673800 of Bertie Withers, "Improvements relating to high voltage oil immersed transformers", which deals with an arrange of the conservator tank to serve the main tank and the inner chamber of the high pressure bushing, in which oil is separated from the main tank, and, uses a Buchholz gas relay, which is one of the objects of replacement by this invention, is not, in any aspects, similar to the object of this invention.
The patent GB6693448 of Smith Leslie; Kingsley Frederick, "Improvements in or relating to electric power transformer", which deals with a system of the breathing sealing of the conservator tank, uses the Buchholz type gas relay in the connection pipe of the main tank to the conservator tank, and its substitution is one of the objects of this invention.
The patent GB710004 of Fenton Laurence Raymond; Howell Ernest Albert, "Improvements in and relating to oil actuated protective relays for transformers and other oil-filled electrical apparatus", which deals with a device similar to the Buchholz gas relay, is not, in any aspects, similar to the object of this invention.
The patent GB1004021 of Du Pont, "Gas detection apparatus", which deals with a gas sensor to operate only in temperatures above 1350° F, is not, in any aspects, similar to the object of this invention.
The patent GB1468404 of Texas Instruments Inc, "Electrical switching devices relays and systems incorporating same", which deals with an electrical switch, is not, in any aspects, similar to this invention.
The patent JP8241818 of Anpo Akinaga, "Oil-Immersed Electric Apparatus", which is a system for collecting and discharging gasses generated by the insulating oil in electric failure condition of the transformer, is not, in any aspects, similar to the object of this invention.
The patent JP8148342 of Kobayashi Nobuo, "Elephant Transformer", which is a transformer with differentiated arrangement, is not, in any aspects, similar to this invention.
The patent JP7029463 of Nojima Hirotaka, "Protective Relay Device For Oil Fill Transformer", which deals with a gas relay enacted by a pressure gas relief valve, with the flow of the insulating oil monitored by an ultrasonic detector, is not, in any aspects, similar to this invention. The patent JP3078216 of Shimizu Yoshiaki, "Oil-Filled Transformer", which deals with a sealing system of the conservator tank and one additional tank for gas expansion and collection of the insulating oil for the case of opening of the sudden pressure relief device, is not, in any aspects, similar to this invention.
The patent JP1158709 of Yamazaki Haruyuki and others, "Nonbuming Transformer", which deals with a transformer that has a device for disposing the gasses generated by the insulating oil upon electrical failures, said device being enacted by a float, and one unit for the de-gasification of the insulating oil, is not, in any aspects, similar to this invention.
The patent JP63287319 of Ohashi Fumio, "Transformer", which deals with a transformer that keeps the actual Buchholz gas relay and adds a gasses detector at the gas relay upstream, is not, in any aspects, similar to this invention.
The patent JP57027005 of Maekawa Koichi, "Transportation Of Oil-Filled Transformer", which deals with one transformer transportation process by using a second conservator tank, is not, in any aspects, similar to this invention. DISCLOSURE OF THE INVENTION
The actual Buchholz Gas Relay presents many inconveniences associated to the principle of operation and to the constructive design itself.
The electric contacts closing action that characterizes the gas relay operation, it is caused by the movement of a levers set, which is moved by the buoyancy float that works in the interface level surface between insulating oil liquid medium and gaseous medium of gasses mass released from insulating oil, creating a gas bed inside the relay's body.
The insulating oil that initially fills total internal volume of relay's body changes the occupied space inside the body with captured and retained gasses mass released from insulating oil, until the creation of a certain gas bed thick enough to promote the float actuation and movement of levers set, which enact electric on-off micro switch.
The mechanic device that moves the electric contacts is a set of fine precision mechanic parts, similar to those produced with high precision clock manufacture technique, comprising a set of articulated arms in unstable balance working. The internal environment of gas relay's body comprising the insulating oil is hostile to operation of such mechanic device, due to formation of sludge what causes jamming of articulated parts by incrustation, which requires constant cleaning and maintenance services. The parts of the mechanic device, as well, are subject to wear and tear due to the friction in the supported points. And, if the electric on-off switch is mercury type, the glass ampoule may break, and then, mercury may contaminate insulating oil, causing serious losses.
The current Buchholz Gas Relay is also vulnerable to said false undue operation. In other words, as the mechanic device is in unstable balance, it is sensible to pressure waves that transit in the insulating oil medium when short-circuits external to the transformer occur, and therefore provoking actuation of relay. For instance, when electric cables of energy distribution networks touch each other, due to wind action or due to branches of the trees movement, they create a short-circuit external to transformer, which responds with abnormal behavior of active parts, generating pressure waves that propagate through insulating oil liquid medium inside transformer. The high number of occurrences for this type of event leads the transformer users to keep the relay turned off; i.e., "jumped", out of operation. And, when the actual condition of electrical failure occurs in active parts, the anomalous state is not detected and it results in a catastrophe for the transformer what may result in explosion and fire.
This electronic gas relay invention is a new device with updated technology for electric power transformer immersed in insulating oil, which allows improvement to techniques of protection and control to transformer, because it makes available continuous electric signals that are proportional to volumetric variation of the bed of gasses released from insulating oil. It is also a definitive solution to solve inconveniences caused by current Buchholz Gas Relay. BRIEF DESCRIPTION OF DRAWINGS
The invention will be more readily appreciated from following description references being had to Figures:
Figure 1A is a scheme for electronic gas relay installation in connecting pipe between main tank and conservator tank for option "in line installation way". Figure 1B is a scheme for electronic gas relay installation in connecting pipe between main tank and conservator tank for option "in high point installation way".
Figure 2 is a drawing of electronic gas relay with constructive design for installation in connecting pipe between main tank and conservator tank for option "in line installation way", that shows a magnet-restrictive electronic sensor device only for presentation purposes.
Figure 3 is a drawing of electronic gas relay with constructive design for installation in the connecting pipe between main tank and conservator tank for option "in high point installation way", that shows a capacitive electronic sensor device only for presentation purposes.
Figures 4A, 4B and 4C are composed by pictures that show the gas bed thickness evolution sequences of gasses released from insulating oil captured and retained in a capacitive type electronic gas relay body with the connection end for option "in high point installation way" in connecting pipe Figures 5A, 5B and 5C are composed by pictures that show the gas bed thickness evolution sequence of gasses released from the insulating oil captured and retained in a magnetic-restrictive type electronic gas relay body with the connection end for option "in high point installation way" in connecting pipe.
Figures 6A, 6B and 6C are composed by pictures that show the gas bed thickness evolution sequences of gasses released from the insulating oil captured and retained in a ultrasonic type electronic gas relay body with the connection end for option "in high point installation way" in connecting pipe.
Figures 7A, 7B and 7C are composed by pictures that show the gas bed thickness evolution sequences of gasses released from the insulating oil captured and retained in a optical refraction of infrared radiation beam type electronic gas relay body with the connection end for option "in high point installation way" in connecting pipe.
Figures 8A, 8B and 8C are composed by pictures that show the gas bed thickness evolution sequences of gasses released from the insulating oil captured and retained in a optical reflection of laser ray radiation beam type electronic gas relay body with the connection end for option "in high point installation way" in connecting pipe.
DETAILED DESCRIPTION OF THE INVENTION
The electronic gas relay is a device for protection of electric power transformer immersed in insulating oil to be installed as option "in line installation way" in connecting pipe 5 of main tank 3 to conservator tank 4 according to Figure 1A1 or to be installed as option "in high point installation way" in connecting pipe 5 according to Figure 1B. The active parts 1, a primordial electrical component of transformer, is immersed in insulating oil liquid medium 2. The main tank 3 is connected to conservator tank 4, through connecting pipe 5, which is the communication way of insulating oil between such tanks.
The constructive design of electronic gas relay 6 for option "in line installation way" in connecting pipe 5 is shown in the drawing of Figure 2. The electronic gas relay 6, object of this invention, has a tight metallic body 11 manufactured with casting material or welded construction with laminated materials, to contain the insulating oil liquid medium 2 and the gasses 10 released from the insulating oil that are separated by an interface level surface 9. The electronic gas relay 6 also comprises: the installation connection ends 18; the sight glass 16; the baffle 17 that promotes deviation of oil flow coarse inside the body 11 and creates a favorable condition for releasing gasses that are in suspension state in insulating oil liquid medium 2; the cover 12 that works as a chamber for capture, retention and detection by an electronic sensor device of the gas bed 10 created with the gasses released from insulating oil; a gas purging orifice 15; the electronic sensor device appropriate for each operation principle, represented in this Figure 2 by the electronic magnet-restrictive sensor device comprising the float 13a that has a magnet in its interior, the stem 13b that contains internally an electrical conductor wire and the electronic circuit module for signal transmitter 14.
The constructive design of electronic gas relay 7 for option "in high point installation way" in the connecting pipe 5 is shown in the drawing of Figure 3. The electronic gas relay 7, object of this invention, has a tight metallic body 21 manufactured with casting material or welded construction with laminated materials, to contain the insulating oil liquid medium 2 that is separated by an interface level surface 9 from the gasses 10 released from the insulating oil. The electronic gas relay 7 is also constituted by: the installation connection end 27 for installing with a block valve 8 attached in connecting pipe 5; the gasses purging orifice 25; the sight glass 26; the cover 22 to close the body for retaining released gasses 10 and to attach the electronic sensor device with electronic circuit module for signal transmitter. This electronic sensor device shall be made accordingly for each operation modal type. Figure 3 shows the capacitive electronic sensor device with capacitive stem 23 and electronic circuit module for signal transmitter 24. Only for simplifying the comprehension of this descriptive text, the following one relates to an electronic gas relay 7 with constructive design for option "in high point installation way" in connecting pipe 5. Therefore the description text is the same for both alternatives: to the electronic gas relay 6 for option "in line installation way" and to the electronic gas relay 7 for option "in high point installation way" in connecting pipe 5.
The electronic gas relay 7 is installed in the connecting pipe 5 at top height elevation position (relative to connecting pipe) below the bottom height elevation position of conservator tank 4. The body 21 , which is initially fulfilled with insulating oil liquid medium 2 , due to its installation arrangement and its geometric form, creates favorable condition to work as a trap for capturing the gasses 10 that are released from insulating oil liquid medium 2.
The gasses dissolved in insulating oil liquid medium 2, when they reach the supersatu ration state, or the gasses generated in electric failures that have not had time enough to solubilize in insulating oil liquid medium 2, become in suspension state in insulating oil liquid medium 2, and go to agglutinate and create gas micro bubbles. The action of thrust force, by Principle of Archimedes, on gasses micro bubbles in suspension state in insulating oil liquid medium 2, causes the travel of such gas micro bubbles towards the upper part of main tank 3, and then, to conservator tank 4 through connecting pipe 5, wherein they are captured inside the body 21 of electronic gas relay 7, continually forming one crescent size bubble, which increases in volume with the capture of other new gas micro bubbles from gasses 10 released from the insulating oil liquid medium 2. The continuous increase in volume of gas bubbles retained internally in upper part of body 21 create a gas bed 10 released from insulating oil, whose thickness also increases with incoming of other new gasses micro bubbles, and the body 21 will be fulfilled with gasses. This dynamic way of creation of gas bed characterizes the body as a favorable environment for release of gasses in suspension state in insulating oil liquid medium 2 and behaves as a chamber for capture and retention of gasses, and allows the actuation of electronic sensor device for the volumetric identification of gasses retained in body 21.
The electronic sensor device identifies the bed volumetric change of gasses 10 released from insulating oil that are retained in the body 21 and may operate according to distinct operation mode such as: the capacitance change for capacitive mode; the time needed to detect a sound produced by Wiedemann Effect for magnet- restrictive mode; the time needed for wave return for ultrasonic mode; the deviation measure of refracted beam for optical refraction of a infrared radiation beam mode; or the deviation measure of reflected beam for optical reflection of a laser ray beam mode.
The capacitive electronic sensor device of electronic gas relay 7, with an electronic circuit module and signal transmitter 4, identifies the bed volumetric change of gasses 10 released from insulating oil and retained in the body 21, through electric capacitance change of capacitor composed by body 21 itself and by a capacitive stem 23, in which electric capacitance value is proportional to dielectric value of presented insulating oil liquid medium 2, which changes due to volume changing of insulating oil liquid medium 2 as consequence of bed volumetric change of gasses 10 released from insulating oil and retained in the body 21. Initially, as shown in Figure 4A, the internal space of body 21 is entirely occupied by insulating oil liquid medium 2; after that, the space is also occupied by the bed of released gasses 10 that is created in upper part of body 21 , according to Figure 4B, and that is separated from the insulating oil by interface level surface 9; until, according to Figure 4C, the bed of released gasses 10 occupies the maximum volume within the internal space of body 21.
The magnet-restrictive electronic sensor device of electronic gas relay 7, with an electronic circuit module and signal transmitter 4, identifies the bed volumetric change of gasses 10 released from the insulating oil and retained inside the body 21 by position of float that has an internal magnet 13b which follows the surface position of interface level surface 9. The float, with a central guide hole, allows the passing of a stem 13a, which contains internally an electric conductor wire for propagation of electrical pulse, which is emitted by electronic circuit module 14. Whether the electrical pulse, when traveling through conductor wire, interacts with the magnetic field of the magnet mounted inside the float 13b, the conductor wire allows a torsion that produces a click sound called Wiedemann Effect. The click sound wave travels through conductor wire to reach the electronic circuit module 14, where it is collected and the time difference between the time from emission of electric pulse and the time for collecting click sound wave determines the bed thickness of gasses 10 released from insulating oil liquid medium and retained in body 21 , which is separated from insulating oil by an interface level surface 9. And, finally, according to Figure 5C, released gasses 10 fill the maximum volume within internal spaces of body 21.
The ultrasonic electronic sensor device of electronic gas relay 7, identifies the bed volumetric change of gasses 10 released from insulating oil and retained in body 21. The electronic sensor device comprising an ultrasound wave emitting / receiving source 31 said ultrasonic transducer and an electronic circuit module and signal transmitter 32, detects the bed volumetric change of gasses 10 contained in body 21 through the bed thickness change, which is identified by response time difference between the ultrasound wave emission and reception times. The ultrasound wave travels through gas medium of gasses bed and reaches the interface level surface 9 of gas-liquid phases; it reflects on the liquid surface and it is collected by electronic sensor device 31 mounted at upper part inside body 21. So it is established the co-relation between emission and reception times difference of ultrasound wave and the bed thickness of gasses retained in body 21. As shown in Figure 6A, the internal space of body 21 is entirely filled by insulating oil liquid medium 2; the space is then beginning to be filled with gasses, as shown in Figure 6B, also the bed is created at internal upper part in body 21 with released gasses 10 which is separated from the insulating oil liquid medium by an interface level surface 9; until, finally, according to Figure 6C, the bed of released gasses 10 occupies the maximum volume within the internal space of body 21. The optical refraction electronic sensor device of electronic gas relay 7, with an electronic circuit module and signal transmitter 43, identifies the bed volumetric change of gasses retained in body 21 through the change of incidence point of refracted infrared radiation beam collected by a set of photocells 42 arranged in upper part of body 21, which was emitted by a source 41 arranged in the inferior part of body 21 with a certain off-set angle relative to interface level surface 9 normal axis, so as the radiation beam, when traveling through insulating oil liquid medium 2 and refracting at interface level surface of gaseous medium 10, the incidence point of radiation beam on photocells set will change according to bed thickness of gasses retained inside body 21. As shown in Figure 7A1 internal space of body 21 is entirely occupied by insulating oil liquid medium 2; after that, as in Figure 7B, upper part of internal space of body 21 is also occupied by the bed of released gasses 10, which is separated from the insulating oil liquid medium by interface level surface 9, and the bed of released gasses 10 increases until it fills the maximum volume within the internal space of body 21, as shown in Figure 7C.
The optical reflection electronic sensor device of electronic gas relay 7, comprising a laser ray beam emitting source 51 mounted in upper part of body 21 , a photocells set 52 sensible to laser ray beam and an electronic circuit module and signal transmitter 53, identifies the bed volumetric change of gasses retained in body 21 through the change of incidence point of the reflected laser ray beam on the photocells set, which is reflected by interface level surface 9, in a certain off-set angle relative to interface level surface 9 normal axis. In this way, when the laser ray beam, traveling through gaseous medium 10, reaches the interface level surface 9, it will reflect and fall upon photocells set at a point that changes according to bed thickness of gasses 10 retained inside body 21. As shown in Figure 8A, in the beginning, internal space of body 21 is entirely occupied by insulating oil liquid medium 2; afterwards, as shown in Figure 8B, this space is also occupied by released gasses 10 that created a bed in upper part of body 21 , which is separated from the insulating oil by interface level surface 9; and, finally, as shown in Figure 8C, the bed of released gasses 10 fills the maximum volume within the internal space of body 21. The electronic components used to make electronic gas relay 7, such as electronic sensor devices and electronic circuit modules and signal transmitter, are commodity devices available in instrumentation specialized market for liquids level measuring and controlling process. The great merit of this invention is to change a mechanical movable set composed of levers and other mobile parts by electronic fixed set composed of electronic sensor devices, electronic circuit modules and signal transmitters, except for floats in case of electronic magnet-restrictive sensor device. This electronic fixed set application for detecting and identifying the bed volumetric change of gasses retained inside body 21 , is an adapted form with inverted function of technologies already established and widely used in liquid level control process. This invention electronic gas relay 6 or 7, independently of its working principle for detecting and identifying the bed volumetric change of gasses 10 released from insulating oil liquid medium and retained inside body 11 or 21 , presents a large series of advantages relative to current Buchholz Gas Relay, such as: it allows greater acuity on detection of bed thickness change of gasses retained inside body 11 or 21 ;it allows dispensing maintenance services that need frequent operations of cleaning of levers mechanisms; it is free of false operation caused by outbreaks from shock waves in transit in insulating oil liquid medium 2; it provides "in high point installation way" of electronic gas relay 7 in connecting pipe 5 with a block valve 8 that allows access to electronic gas relay 7 without need to turn off the transformer; and, it allows continually identifying in proportional regimen the gasses bed volumetric change, that allows development of news tools for better monitoring of transformer.
At last, the use of this invention electronic gas relay 6 or 7 in any of the operation kinds increases reliability of protection and control system for electrical power transformer immersed in insulating oil.

Claims

1. 1 claim Electronic Gas Relay for electric power transformer immersed in insulating oil, characterized by electric signals output generated by means of electronic sensor device operation from quantification of bed volumetric change of gasses released from insulating oil liquid medium which create a gas bed within relay's metallic body.
2. I claim Electronic Gas Relay according to claim 1 , characterized by having one connection end for installation in a high point of connecting pipe between transformer main tank and conservator tank, to capture and retain gasses released from insulating oil liquid medium.
3. I claim Electronic Gas Relay according to claim 1 , that has two connection ends for in line installation in connecting pipe between transformer main tank and conservator tank, characterized by having within the metallic body, a baffle to deflect the insulating oil flow into the relay's body and promote a greater release performance of gasses in suspension state in insulating oil liquid medium.
4. I claim Capacitive Type Electronic Gas Relay according to claims 1 , 2 and 3, characterized by the electronic sensor device work being based in capacitance value change of capacitor composed by relay's metallic body itself and a capacitive stem, due to bed volumetric change of gasses retained within relay's metallic body which change the dielectric value of medium.
5. I claim Magnet-Restrictive Type Electronic Gas Relay according to claims 1 , 2 and 3, characterized by the electronic sensor device work being based on difference time between emission time of an electric pulse and reception time of a click sound wave produced by torsion of internal conductor wire inside stem when emitted electric pulse interacts with the magnetic field of the magnet contained within the float that follows the position of interface level surface between insulating oil liquid medium and gaseous medium due to bed volumetric change of gasses retained within relay's metallic body.
6. I claim Ultrasonic Type Electronic Gas Relay according to claims 1 , 2 and 3, characterized by the electronic sensor device work being based on time difference between the emission time of one ultrasonic wave emitted by sensor device and the reception time of ultrasonic wave reflected on the interface level surface between insulating oil liquid medium and gaseous medium that changes its position according to bed volumetric change of gasses retained within relay's metallic body.
7. I claim Optical Refraction Type Electronic Gas Relay according to the claims 1 , 2 and 3, characterized by the electronic sensor device work being based on the proportional change of incidence point along photocells set by an infrared radiation beam refracted from insulating oil liquid medium to gaseous medium of gasses mass, originated from an infrared radiation beam emitting source mounted inside the liquid medium, at inclined position with a constant and appropriate angle relative to surface normal axis, so that the position of rise out point of refracted infrared radiation beam, relative to surface normal axis of interface level surface of insulating oil liquid medium and gaseous medium, changes due to bed volumetric change of gasses retained within the relay's metallic body.
8. I claim Optical Reflection Type Electronic Gas Relay according to claims 1 , 2 and 3, characterized by the electronic sensor device work being based on the proportional change of incidence point along a photocells set mounted at upper part inside relay's body by a laser ray beam emitted from a source located in relay's upper part and reflected by the interface level surface from insulating oil liquid medium and gaseous medium, due to bed volumetric change of gasses retained within relay's metallic body.
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