Electronic voltage sensor

Abstract

The present invention relates to an electronic voltage sensor that can be used in a gas-insulated switchgear. An electronic voltage sensor according to one embodiment comprises a pair of electrodes formed in a ring shape to allow a conductor to pass through and arranged concentrically, a ring-shaped insulator arranged concentrically between the pair of electrodes, and a molding portion formed by molding the stacked pair of electrodes and the insulator to form an integrated structure. The molding portion may include a single molding layer comprising an insulating resin, an organic phase change material, and an inorganic phase change material, or a first molding layer comprising an insulating resin and an organic phase change material, and a second molding layer comprising an insulating resin and an inorganic phase change material.

Description

Technology Field

[0001] The present invention relates to an electronic voltage sensor. Background Technology

[0002] In response to customer demand for digital substation automation, the transition to intelligent gas-insulated switchgear (GSW) systems incorporating Low Power Voltage Transformer (LPVT) technology is accelerating.

[0003] Low-power electronic transformers use a capacitance voltage divider as a sensor probe and require high precision non-error performance with an output error rate of ±0.2% and a phase difference of ±10 min at 80% / 100% / 120% of the rated voltage.

[0004] However, due to changes in external and internal tank temperatures of the gas-insulated switchgear, changes in the capacitance values ​​caused by the insulating gas (SF6 or eco-friendly gas) between the conductor and the sensor probe, as well as the capacitance of the sensor probe itself, act as factors causing changes in the output of the low-power electronic transformer, resulting in a decrease in non-error precision.

[0005] In the past, to overcome this problem, a signal conversion circuit that receives the output voltage (V) of the sensor probe as an input signal had to implement a separate function to enable temperature compensation, and thus measurements of sensor probe output and phase change data were performed in each temperature range based on the rated voltage, but there were difficulties in obtaining experimental data of output and phase change by temperature. The problem to be solved

[0006] The purpose of the present invention is to provide an electronic voltage sensor. means of solving the problem

[0007] An electronic voltage sensor according to the present invention comprises a pair of electrodes formed in a ring shape through which a conductor passes and arranged concentrically, a ring-shaped insulator arranged concentrically between the pair of electrodes, and a molding portion formed by molding the stacked pair of electrodes and the insulator to form an integrated structure, wherein the molding portion may include a single molding layer comprising an insulating resin, an organic phase change material, and an inorganic phase change material, or a first molding layer comprising an insulating resin and an organic phase change material, and a second molding layer comprising an insulating resin and an inorganic phase change material.

[0008] The above pair of electrodes includes a first electrode and a second electrode, and the diameter of the insulator is larger than the diameter of the first electrode and smaller than the diameter of the second electrode, so that the insulator is located inside the second electrode and the first electrode is located inside the insulator.

[0009] A signal line can be connected to each of the first electrode and the second electrode.

[0010] The insulator may have a width greater than the width (axial length) of the pair of electrodes.

[0011] The above organic phase change material and the above inorganic phase change material may be in a solid phase.

[0012] The above organic phase change material may include an alkane-based phase change material having 10 to 20 carbon atoms.

[0013] The above inorganic phase change material may be one or more selected from the group consisting of Mn(NO3)3·6H2O, Zn(NO3)3·6H2O, Mn(NO3)3·4H2O, Na2SO4·10H2O and CH3COONa·3H2O.

[0014] The above insulating resin may independently be one or more selected from the group consisting of epoxy resin, acrylic resin, and silicone resin.

[0015] The insulating resin included in each of the above-mentioned single molding layer, the first molding layer, and the second molding layer may be independently included in an amount of 50% or more by weight relative to the total weight of each of the above-mentioned single molding layer, the first molding layer, and the second molding layer.

[0016] The weight ratio of the organic phase change material and the inorganic phase change material included in the above-mentioned single molding layer may be 1:9 to 9:1.

[0017] The above electronic voltage sensor can measure the voltage flowing through the conductor using the capacitance voltage division principle.

[0018] When the above electronic voltage sensor is applied to a device in an atmosphere of insulating gas, a voltage divider circuit is formed by a first capacitance acting by the insulating gas between the conductor and the electronic voltage sensor, and a second capacitance existing between the insulator and the molding part of the electronic voltage sensor, and the voltage divider ratio of the voltage divider circuit is

[0019]

[0020] Here, C1 is the first capacitance [F], C2 is the second capacitance [F], U p is the voltage [V] applied by the conductor, and U out may be defined as the voltage [V] output from the above electronic voltage sensor.

[0021] It may further include a housing that accommodates the above electronic voltage sensor. Effects of the invention

[0022] According to an embodiment of the present invention, the rate of change in sensor probe output with respect to temperature change can be reduced.

[0023] In addition, according to an embodiment of the present invention, the problem of reduced non-error precision can be improved. Brief explanation of the drawing

[0024] FIG. 1 is a cross-sectional view illustrating an electronic voltage sensor according to one embodiment of the present invention. FIG. 2 is a perspective view illustrating an electronic voltage sensor according to one embodiment of the present invention. FIG. 3 briefly illustrates the upper surface of one side of the first mold and the side surfaces of both sides of the first mold that can be used to form the first molding layer. FIG. 4 briefly illustrates the upper surface of one side of the second mold and the side surfaces of both sides of the second mold that can be used to form the second molding layer. Figure 5(a) shows the process of fixing the electrode portion to one side of the first mold and assembling both sides of the first mold; (b) shows the first molding layer composition being injected into the first mold injection port after both sides of the first mold are connected, so that the electrode portion is integrated with the first molding layer; (c) shows the process of fixing the electrode portion integrated with the first molding layer to one side of the second mold and assembling both sides of the second mold; and (d) shows the electrode portion being integrated with the first and second molding layers after both sides of the second mold are connected and the second molding layer composition is injected into the second mold injection port. Specific details for implementing the invention

[0025] The present invention is described in detail below with reference to exemplary drawings. It should be noted that in assigning reference numerals to the components of each drawing, the same components are given the same reference numeral whenever possible, even if they are shown in different drawings.

[0026] Furthermore, for convenience of explanation, this specification describes and illustrates the invention primarily with examples in which an electronic voltage sensor is applied to a gas-insulated switchgear, but the invention is not necessarily limited thereto. An electronic voltage sensor according to one embodiment of the present invention may also be applied to any other device, such as an instrument transformer or a substation, that is in an atmosphere of an insulating gas, such as sulfur hexafluoride gas.

[0027] Additionally, for the sake of convenience of explanation in this specification, the voltage sensor refers to an electronic voltage sensor.

[0028] FIG. 1 is a cross-sectional view illustrating an electronic voltage sensor according to one embodiment of the present invention, and FIG. 2 is a perspective view illustrating an electronic voltage sensor according to one embodiment of the present invention.

[0029] As illustrated in FIGS. 1 and 2, a voltage sensor according to one embodiment of the present invention may include an electrode portion (100) comprising a pair of electrodes and an insulator, and a molding portion (210, 220).

[0030] A pair of electrodes can be formed into a ring shape using a metallic conductor with excellent electrical conductivity, such as copper or silver. A pair of electrodes may include a first electrode and a second electrode, wherein the diameter of the first electrode is smaller than the diameter of the second electrode.

[0031] A pair of electrodes can be arranged concentrically. In other words, a first electrode with a relatively small diameter can be positioned inside a second electrode with a relatively large diameter.

[0032] In addition, a pair of electrodes can have substantially the same width and thickness.

[0033] A signal line for voltage sensing can be physically and electrically connected to each electrode, for example, by soldering. For example, a positive (+) signal line can be connected to the first electrode, and a negative (-) signal line can be connected to the second electrode.

[0034] The insulator can be formed into a ring shape using a flexible insulating material, such as fiber reinforced plastics (FRP) or polyimide (PI) resin.

[0035] The diameter of the insulator is larger than the diameter of the first electrode and smaller than the diameter of the second electrode. The insulator can be arranged concentrically with a pair of electrodes. In other words, the insulator can be located inside the second electrode, which has a relatively larger diameter, and the first electrode, which has a relatively smaller diameter, can be located inside the insulator.

[0036] In addition, the insulator is preferably larger than the width (axial width) of the pair of electrodes. For example, to stably connect a signal line to a first electrode located radially inside the insulator, the signal line may be fixed to the insulator by soldering or the like, and then connected to the first electrode through the insulator. Here, the axial width may refer to a direction passing through the center of the diameter of the pair of electrodes and parallel to the surface of the pair of electrodes.

[0037] The molding portion may include a single molding layer comprising an insulating resin, an organic phase change material, and an inorganic phase change material, or a first molding layer comprising an insulating resin and an organic phase change material, and a second molding layer comprising an insulating resin and an inorganic phase change material. As shown in FIGS. 1 and 2, the electrode portion integrated with the first molding layer may have a form integrated with the second molding layer, or the electrode portion integrated with the second molding layer may have a form integrated with the first molding layer (not shown).

[0038] In a stacked state with an insulator interposed between a pair of electrodes, the stacked pair of electrodes and the insulator can be molded into a ring shape by a molding material, covered, and fixed to each other. Together with this molded portion, the pair of electrodes and the insulator are integrated to form a single voltage sensor. Here, the molding material may refer to a composition comprising an insulating resin and a phase change material.

[0039] Phase Change Materials (PCMs) are classified into organic and inorganic categories and can also be referred to as latent heat materials, thermal storage materials, cold storage materials, or thermal regulating materials. Phase Change Materials can accumulate or release large amounts of thermal energy while undergoing a physical change from their initial state due to temperature variations, such as transitioning from solid to liquid to solid or from liquid to gas to liquid.

[0040] Organic phase change materials and inorganic phase change materials can be in a solid state or in powder form.

[0041] It is desirable to apply two or more types of phase change materials with different temperatures at which phase change occurs depending on the target temperature. For example, based on 25°C, for temperature conditions lower than this, a powder-type alkane-based phase change material protected by microcapsules can be considered.

[0042] The above organic phase change material may be an alkane-based phase change material having 10 to 20 carbon atoms, and examples include dodecane, tridecane, tetradecane, pentadecane, etc.

[0043] The above inorganic phase change material may be a metal salt hydrate, specifically a metal salt hydrate such as a nitrate, sulfate, or acetate containing manganese, zinc, sodium, etc., and more specifically, one or more selected from the group consisting of Mn(NO3)3·6H2O, Zn(NO3)3·6H2O, Mn(NO3)3·4H2O, Na2SO4·10H2O, and CH3COONa·3H2O.

[0044] The insulating resin may be any resin having insulating properties such as epoxy resin, and may be one or more selected from the group consisting of, for example, epoxy resin, acrylic resin, and silicone resin. The insulating resin may be a polymer resin, and may have a weight-average molecular weight (Mw) of 1,000 g / mol or more, specifically 1,000 g / mol to 1,000,000 g / mol, more specifically 10,000 g / mol to 800,000 g / mol, but is not limited thereto.

[0045] The insulating resin included in each of the single molding layer, the first molding layer, and the second molding layer may be included in an amount of 50% by weight or more with respect to the total weight of each of the single molding layer, the first molding layer, and the second molding layer. For example, the single molding layer may include an insulating resin in an amount of 50% by weight or more with respect to the total weight of the single molding layer, and may include an organic phase change material and an inorganic phase change material in an amount of 50% by weight or less with respect to the total weight of the single molding layer. As another example, the first molding layer may include an insulating resin in an amount of 50% by weight or more with respect to the total weight of the first molding layer and an organic phase change material in an amount of 50% by weight or less, and the second molding layer may include an insulating resin in an amount of 50% by weight or more with respect to the total weight of the second molding layer and an inorganic phase change material in an amount of 50% by weight or less.

[0046] The weight ratio of the organic phase change material and the inorganic phase change material included in the single molding layer may be 1:9 to 9:1, and specifically, depending on the temperature change conditions of the environment in which the sensor probe is installed, the low-temperature phase change material and the high-temperature phase change material may be composed of a mixing ratio (weight ratio) of 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, or 9:1, and the low-temperature phase change material may be an organic phase change material or an inorganic phase change material as a material capable of undergoing a phase change at a lower temperature, and the high-temperature phase change material may be an inorganic phase change material or an organic phase change material as a material capable of undergoing a phase change at a higher temperature. For example, the present invention includes a low-temperature phase change material and a high-temperature phase change material, either separately or in combination, in the molding layer, so that the change in sensor probe output with respect to temperature change can show a change in output of about +4% higher at -40℃ relative to 25℃, and a change in output of -1.2% lower at +40℃.

[0047] With respect to the electrode portion, a first molding layer may be formed first and then a second molding layer may be formed, or the second molding layer may be formed first and then the first molding layer may be formed.

[0048] Figures 1 and 2 show an example in which, with respect to the electrode portion, a first molding layer is formed first and then a second molding layer is formed.

[0049] FIG. 3 briefly illustrates the upper surface of one side of a first mold and the side surfaces of both sides of the first mold that can be used to form a first molding layer. The first mold may include a first mold injection port (11) capable of injecting a first molding layer composition and a first mold body part (12) forming a space into which the first molding layer composition is injected.

[0050] FIG. 4 briefly illustrates the upper surface of one side of a second mold and the side surfaces of both sides of the second mold that can be used to form a second molding layer. The second mold may include a second mold injection port (21) capable of injecting a second molding layer composition and a second mold body part (22) forming a space into which the second molding layer composition is injected.

[0051] The molding portion enables a pair of electrodes and an insulator to be completely sealed and bonded during the process of molding the electrode portion into a single molding layer or a first molding layer and a second molding layer, and also enables the shape of the voltage sensor to be stably maintained.

[0052] One embodiment of the method for manufacturing an electronic voltage sensor of the present invention may include manufacturing a single molding composition, fixing an electrode portion to a single mold, and then injecting the single molding composition to integrate the electrode portion and the single molding layer. Here, the single molding composition comprises an insulating resin, an organic phase change material, and an inorganic phase change material, wherein the insulating resin may be included in an amount of 50% by weight or more and the organic phase change material and the inorganic phase change material may be included in an amount of 50% by weight or less relative to the total weight of the single molding composition. In addition, the organic phase change material and the inorganic phase change material may be composed of a mixing ratio (weight ratio) of 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, or 9:1 depending on the temperature change conditions of the environment in which the sensor probe is installed.

[0053] Referring to FIG. 5, another embodiment of the method for manufacturing an electronic voltage sensor of the present invention may include manufacturing a first molding composition and a second molding composition, fixing an electrode portion to one side of the first mold, assembling both sides of the first mold, and then injecting the first molding layer composition into the first mold injection port (11) so that the electrode portion and the first molding layer are integrated, fixing the electrode portion integrated with the first molding layer to one side of the second mold, assembling both sides of the second mold, and then injecting the second molding layer composition into the second mold injection port (21) so that the electrode portion and the first and second molding layers are integrated. Here, the first molding composition comprises an insulating resin and an organic phase change material, and with respect to the total weight of the first molding composition, the insulating resin may be included in an amount of 50% by weight or more, and the organic phase change material may be included in an amount of 50% by weight or less. Additionally, the second molding composition comprises an insulating resin and an organic phase change material, and with respect to the total weight of the second molding composition, the insulating resin may be included in an amount of 50% by weight or more, and the inorganic phase change material may be included in an amount of 50% by weight or less. Furthermore, the organic phase change material and the inorganic phase change material may be composed in a weight ratio of 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, or 9:1 depending on the temperature change conditions of the environment in which the sensor probe is installed. Meanwhile, the method may include fixing an electrode portion to a first mold and injecting the second molding composition to integrate the electrode portion and the second molding layer, fixing the electrode portion integrated with the second molding layer to a second mold, and injecting the first molding layer composition to integrate the electrode portion and the first and second molding layers.

[0054] For the preparation of a single molding composition, a first molding composition, and a second molding composition, sufficient stirring is performed under vacuum using a magnetic stirrer or a motor stirrer at a water bath temperature of 30 to 40°C to ensure homogeneous dispersion of the phase change material within the insulating resin (polymer resin), and the composition containing the phase change material after stirring is performed a second stirring with a curing agent for polymer resin, and then vacuum degassing is performed to remove bubbles.

[0055] The final manufactured single molding composition, the first molding composition, or the second molding composition can be injected into a metal or Teflon mold (first mold, second mold) preheated to 40 to 50°C in which a sensor probe (electrode part) is fixedly mounted, and by removing bubbles generated during curing in a vacuum oven, an electronic voltage sensor can be manufactured as a sensor probe of a low-power electronic transformer electrically insulated molded with a final phase change material.

[0056] The voltage sensor of the present invention can precisely measure the voltage flowing through a conductor by utilizing the principle of capacitance voltage division. The ring-shaped voltage sensor is formed and mounted so that a conductor carrying current passes through it, thereby enabling the detection of the voltage magnitude using a non-contact method. Consequently, the voltage sensor can omit the iron core, which in turn eliminates the occurrence of iron resonance.

[0057] When an electronic voltage sensor is applied to a device in an atmosphere of insulating gas, such as a gas-insulated switchgear, and the voltage sensor is installed so as to surround a conductor within a tank, that is, to be penetrated by the conductor, a voltage divider circuit can be formed between the conductor within the tank and the voltage sensor by a first capacitance (C1) acting by an insulating gas, such as sulfur hexafluoride gas, and a second capacitance (C2) possessed by the voltage sensor itself, that is, existing in the insulator and the molding part.

[0058] In this voltage divider circuit, the voltage division ratio of the voltage sensor varies according to the capacitance, and while the value of the second capacitance (C2) can be maintained constant as the combined value of the capacitance of the insulator and the molding part, the value of the first capacitance (C1) changes according to the temperature of the insulating gas.

[0059] Accordingly, for example, the temperature of the insulating gas can be measured from a temperature sensor mounted on the tank of a gas-insulated switchgear, and the value of the first capacitance (C1) can be obtained by correcting the capacitance of the insulating gas with the rate of change of capacitance according to the measured temperature, i.e., the temperature coefficient of capacitance.

[0060] The partial pressure ratio can be expressed by the following mathematical formula.

[0061]

[0062] Here, C1 is the first capacitance due to the insulating gas [F], C2 is the second capacitance possessed by the voltage sensor itself [F], U p is the voltage applied by the conductor [V], and U out is the voltage [V] output from the voltage sensor.

[0063] As described above, for example, in the case where a voltage sensor is installed to surround a conductor, that is, to be penetrated by the conductor, within the tank of a gas-insulated switchgear, the voltage sensor may be installed in the connecting ring unit of the tank. The connecting ring unit may connect the first tank and the second tank by contacting each of these tanks between the first tank and the second tank constituting the tank. The connecting ring unit may be positioned adjacent to the circuit breaker constituting the gas-insulated switchgear in the tank.

[0064] Here, the configuration and structure of the electronic voltage sensor, the connecting ring unit for installing the electronic voltage sensor, and the configuration and arrangement relationships of the transmitting unit that receives measurement information from the voltage sensor, amplifies it, and transmits it to the data processing unit are described in detail in the applicant’s Korean Registered Patent No. 2458873 and Published Patent Application No. 10-2024-0109375. Therefore, the description and illustration thereof are omitted in this specification, and it is merely noted that the contents of the aforementioned patents may be incorporated by reference into this specification.

[0065] In order to be coupled to or separated from such a connecting ring unit, a voltage sensor according to one embodiment of the present invention can be modularized.

[0066] The voltage sensor may further include a housing that accommodates the voltage sensor.

[0067] The housing may include a main body formed to have a ring shape using a non-magnetic material, such as aluminum or an aluminum alloy. Additionally, the housing may have a flange extending radially outward from the main body and may include a plurality of bolt holes formed at regular intervals in the flange.

[0068] A single sensing module can be formed by inserting and accommodating a voltage sensor within the main body of the housing.

[0069] In this case, the housing is made of a non-magnetic material to shield the voltage sensor, thereby minimizing the influence of magnetic fields caused by current flow on the voltage sensor. As a result, the voltage sensor is minimally affected by magnetic fields and noise, enabling precise voltage measurement.

[0070] In addition, since the voltage sensor is modularized, in the event of damage to the voltage sensor, only the damaged voltage sensor can be replaced from equipment such as a gas-insulated switchgear.

[0071] The above description is merely an illustrative explanation of the technical concept of the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications and variations within the scope of the essential characteristics of the present invention.

[0072] Accordingly, the embodiments disclosed in this invention are intended to explain, not limit, the technical concept of the invention, and the scope of the technical concept of the invention is not limited by these embodiments. The scope of protection of this invention shall be interpreted by the claims below, and all technical concepts within an equivalent scope shall be interpreted as being included within the scope of rights of this invention. Explanation of the symbols

[0073] 100: Electrode part 210: 1st molding layer 220: Second molding layer 11: 1st mold injection port 12: First mold main body part 21: Second mold injection port 22: Second mold main body part

Claims

Claim 1 An electronic voltage sensor comprising: a pair of electrodes formed in a ring shape to allow a conductor to pass through and arranged concentrically; a ring-shaped insulator arranged concentrically between the pair of electrodes; and a molding portion formed by molding the stacked pair of electrodes and the insulator to form an integrated structure, wherein the molding portion comprises a first molding layer comprising an insulating resin and an organic phase change material, and a second molding layer comprising an insulating resin and an inorganic phase change material. Claim 2 An electronic voltage sensor according to claim 1, wherein the pair of electrodes comprises a first electrode and a second electrode, and the diameter of the insulator is larger than the diameter of the first electrode and smaller than the diameter of the second electrode, so that the insulator is located inside the second electrode and the first electrode is located inside the insulator. Claim 3 An electronic voltage sensor according to paragraph 2, wherein signal lines are connected to the first electrode and the second electrode, respectively. Claim 4 In paragraph 2, the insulator is an electronic voltage sensor having a width greater than the width (axial length) of the pair of electrodes. Claim 5 An electronic voltage sensor according to claim 1, wherein the organic phase change material and the inorganic phase change material are in a solid phase. Claim 6 An electronic voltage sensor according to claim 1, wherein the organic phase change material comprises an alkane-based phase change material having 10 to 20 carbon atoms. Claim 7 An electronic voltage sensor according to claim 1, wherein the inorganic phase change material is one or more selected from the group consisting of Mn(NO3)3·6H2O, Zn(NO3)3·6H2O, Mn(NO3)3·4H2O, Na2SO4·10H2O, and CH3COONa·3H2O. Claim 8 An electronic voltage sensor according to claim 1, wherein the insulating resin is independently one or more types selected from the group consisting of epoxy resin, acrylic resin, and silicone resin. Claim 9 An electronic voltage sensor according to claim 1, wherein the insulating resin included in each of the first molding layer and the second molding layer is independently included in an amount of 50% by weight or more with respect to the total weight of each of the first molding layer and the second molding layer. Claim 10 An electronic voltage sensor according to claim 1, wherein the stacked pair of electrodes and the insulator are integrated with the first molding layer and then integrated with the second molding layer, or integrated with the second molding layer and then integrated with the first molding layer. Claim 11 In claim 1, the electronic voltage sensor measures the voltage flowing through the conductor using the capacitance voltage division principle. Claim 12 In claim 11, when the electronic voltage sensor is applied to a device in an atmosphere of insulating gas, a voltage divider circuit is formed by a first capacitance acting by the insulating gas between the conductor and the electronic voltage sensor, and a second capacitance existing between the insulator and the molding part of the electronic voltage sensor, and the voltage divider ratio of the voltage divider circuit is Here, C1 is the first capacitance [F], C2 is the second capacitance [F], U p is the voltage [V] applied by the conductor, and U out An electronic voltage sensor defined as the voltage [V] output from the above electronic voltage sensor. Claim 13 An electronic voltage sensor according to any one of claims 1 to 12, further comprising a housing for accommodating the electronic voltage sensor.

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