High-voltage electrode cup, related device and method

Abstract

The invention provides a high-voltage electrode cup, a related device and a method. In the high-voltage electrode cup, a shielding electrode of an electrode cup main body is arranged at the upper part of an inner electrode; the insulating positioning ring is fixed around the outer side wall of the shielding electrode; the shielding cover is fixed on the shielding electrode, and the bottom of the shielding cover abuts against the upper part of the shielding electrode; the elastic measuring contact is fixed between the insulating ring and the shielding electrode and is connected with the inner electrode; the micro-current measuring plug passes through the shielding case and the insulating ring to be connected with the elastic measuring contact; the electrode cup main body and the outer electrode are fixed through the insulating fastening cover; the insulating fixed outer ring is in contact with the inner side wall of the outer electrode; the outer electrode and the inner electrode are concentric rings, and the electrode distance between the outer electrode and the inner electrode is a preset distance. The high-voltage electrode cup can provide an electric field type and electric field intensity similar to actual working conditions of a converter transformer, is directly used for measuring the conductivity of transformer oil under high electric field intensity, and is beneficial to miniaturization of a device adopting the high-voltage electrode cup.

Description

Technical Field

[0001] The invention relates to a high voltage electrode cup, a related device and a method. Background Art

[0002] The converter transformer is the core power transmission and transformation equipment of the UHV DC transmission project. The insulation design of the converter transformer is based on the conductivity parameters of the insulating material. It is particularly important to accurately measure the conductivity parameters of the insulating material under the operating conditions of the converter transformer.

[0003] There are no instruments and test methods for measuring the conductivity of transformer oil under the operating conditions of converter transformers at home and abroad. At present, the following two methods are mainly used to test the conductivity of transformer oil. One test method is to use instruments that meet the standards, such as GB / T5654 (IEC60247) standard "Measurement of relative permittivity, dielectric loss factor and DC resistivity of liquid insulating materials", and take the reciprocal of the measured DC resistivity as the conductivity. The other test method is to use a flat three-terminal high-voltage electrode cup to measure the conductivity under the flat electric field. Summary of the invention

[0004] In order to better measure the conductivity of transformer oil under high field strength, the embodiment of the present invention proposes a high-voltage electrode cup, a related device and a method. The technical solution proposed by the present invention is as follows:

[0005] In a first aspect, an embodiment of the present invention provides a high-voltage electrode cup, comprising: an electrode cup body, an outer electrode, and an insulating fastening cover;

[0006] The electrode cup body comprises an inner electrode, a shielding electrode, an insulating positioning ring, a micro-current measurement plug, an elastic measurement contact, an insulating ring, and a shielding cover;

[0007] The shielding electrode is disposed on the upper portion of the inner electrode;

[0008] The insulating positioning ring is fixed around the outer side wall of the shielding electrode;

[0009] The shielding cover is fixed on the shielding electrode, and the bottom of the shielding cover abuts against the upper part of the shielding electrode;

[0010] The elastic measuring contact is fixed between the insulating ring and the shielding electrode, and is connected to the inner electrode;

[0011] The micro-current measurement plug passes through the shielding cover and the insulating ring to connect the elastic measurement contact;

[0012] The electrode cup body and the outer electrode are fixed by the insulating fastening cover, and the insulating fixed outer ring is in contact with the inner side wall of the outer electrode;

[0013] The outer electrode and the inner electrode are concentric rings, and the electrode spacing between the outer electrode and the inner electrode is a preset spacing.

[0014] In a specific embodiment, the electrode cup body further comprises: an inner electrode temperature sensor and an inner electrode electric heating rod;

[0015] The inner electrode temperature sensor and the inner electrode electric heating rod are arranged on the inner electrode.

[0016] In a specific embodiment, the high-voltage electrode cup further includes an external electrode temperature sensor;

[0017] The side wall of the outer electrode is provided with an insertion hole, and the outer electrode temperature sensor is arranged in the insertion hole.

[0018] In a specific embodiment, the high-voltage electrode cup further includes a high-voltage electrical plug;

[0019] The high voltage electric plug is arranged on the outer electrode.

[0020] In a specific embodiment, the electrode spacing between the inner electrode and the outer electrode is 2 mm±0.05 mm, and the concentricity deviation between the inner electrode and the outer electrode is less than 0.05 mm.

[0021] In one embodiment, the empty cup nominal capacitance of the high voltage electrode cup is 60±1 pF, and the empty cup insulation resistance is greater than 3×1012Ω.

[0022] In a specific embodiment, the insulation strength of the insulating positioning ring is sufficient to withstand a high voltage of ±10kV.

[0023] In a second aspect, an embodiment of the present invention provides a device capable of measuring the conductivity of transformer oil under high field strength conditions, comprising: the above-mentioned high-voltage electrode cup, a DC high-voltage power supply, an electromagnetic heating system and a control system;

[0024] The high-voltage electrode cup is embedded in the electromagnetic heating system;

[0025] The control system is connected to the micro-current measuring plug and is used to measure the micro-current passing through the transformer oil in the high-voltage electrode cup;

[0026] The DC high voltage power supply is connected to the outer electrode of the high voltage electrode cup;

[0027] The control system is connected to the DC high voltage power supply and is used to control the voltage and polarity applied to the high voltage electrode cup;

[0028] The control system is connected to the electromagnetic heating system through an electromagnetic heating control line and is used to control the temperature of the electromagnetic heating system.

[0029] In a specific embodiment, the electromagnetic heating system includes: an electromagnetic coil;

[0030] When the high-voltage electrode cup is embedded in the electromagnetic heating system, the electromagnetic coil is distributed around the high-voltage electrode cup.

[0031] In a specific embodiment, the control system includes a high-precision micro-ammeter;

[0032] The high-precision micro-ammeter is connected to the micro-current measuring plug of the high-voltage electrode cup and is used to measure the micro-current passing through the transformer oil in the high-voltage electrode cup.

[0033] In a specific embodiment, the microcurrent test range of the high-precision microammeter is 1×10-13A to 1×10-2A, and the resolution is 1×10-13A.

[0034] In a specific embodiment, the control system further comprises: an integrated control box;

[0035] The integrated control box is connected to the high-voltage electrode cup oil temperature sensor, the inner electrode temperature sensor, the inner electrode electric heating rod and the outer electrode temperature sensor, and is connected to the electromagnetic coil for setting and controlling the test temperature;

[0036] The integrated control box is connected to a high-precision micro-ammeter for collecting and recording the micro-current of the transformer oil in the high-voltage electrode cup;

[0037] The integrated control box is connected to the high-voltage DC power supply and is used to set the DC high voltage value and the polarity of the DC high voltage, and to set the charging time and the discharging time.

[0038] In a specific embodiment, the control system further comprises the touch screen liquid crystal display;

[0039] The touch screen liquid crystal display is connected to the integrated control box and is used for inputting experimental parameters and displaying real-time control parameters and experimental results.

[0040] In a third aspect, the present invention provides a method for measuring the electrical conductivity of transformer oil under high field strength conditions, comprising:

[0041] Disassemble and clean the high-voltage electrode cup and dry, assemble and inspect it;

[0042] Turn on the control system and set the test temperature, electric field strength, polarity and electrification time;

[0043] Mix the test sample evenly and slowly inject it into the high voltage electrode cup;

[0044] Installing the high voltage electrode cup into an electromagnetic heating system;

[0045] The control system controls the heating of the high-voltage electrode cup, and after detecting that the oil temperature in the high-voltage electrode cup reaches the test temperature, the test temperature is kept constant for a preset time, and the high-voltage electrode cup is pressurized, charged and measured by a high-voltage DC power supply to obtain a test result;

[0046] The oil cup of the high-voltage electrode cup is drained, and the above test process is executed again to perform parallel tests until the results of two adjacent tests meet the preset conditions, and the conductivity is calculated.

[0047] In a specific embodiment, the method further comprises:

[0048] After obtaining the applied DC voltage value and the measured sample current value, the conductivity is calculated using the following formula:

[0049] σ=I / K·U

[0050] In the formula: σ represents conductivity; K represents the empty electrode constant; I represents the measured sample current value; U represents the applied DC voltage value; among them, K=0.113Ca, Ca represents the empty cup electrode capacitance value of the high voltage electrode cup.

[0051] The beneficial effects of the above technical solution provided by the embodiment of the present invention include at least:

[0052] The high-voltage electrode cup provided in the embodiment of the present invention fixes the electrode cup body in the outer electrode by an insulating fastening cover. Since the outer electrode and the inner electrode in the electrode cup body are concentric rings, the electrode spacing between the two is a preset spacing. Therefore, the electric field type formed by the concentric electrodes between the two is similar to the actual working condition of the converter transformer. Since the insulating positioning ring is fixed on the shielding electrode, the micro-current measurement plug passes through the shielding cover and the insulating ring and is connected to the inner electrode via the elastic measurement contact, thereby ensuring the insulation performance of the inner electrode and the micro-current measurement plug, and the insulating positioning ring contacts the inner side wall of the outer electrode, thereby increasing the insulation distance and improving the insulation strength, avoiding surface discharge, and enabling the high-voltage electrode cup to meet the insulation requirements for withstanding high voltage; it is connected to the micro-current measurement plug through the shielding cover, and the structure including the shielding electrode and the inner electrode is shielded for signal, thereby ensuring stability and accuracy during test measurement.

[0053] The high-voltage electrode cup provided in the embodiment of the present invention can be applied to a device for measuring the conductivity of transformer oil under a high-field strength electric field, so that the electric field strength used by the device can meet the electric field strength of 2kV / mm to 4kV / mm that the transformer oil in the converter transformer is subjected to, and can withstand high voltage, and directly and reliably measure the conductivity of the transformer oil under high field strength conditions. Since the high-voltage electrode cup is an electric field type formed by concentric circle electrodes, which is similar to the actual working condition of the converter transformer, and the volume of the high-voltage electrode cup is small, it is conducive to the miniaturization of the measuring device using the high-voltage electrode cup, so that the device can be directly used as a transformer oil product factory inspection instrument, providing a basis for the design and oil selection of the converter transformer and the product development, quality control and factory inspection of the converter transformer oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 for Figure 3 Schematic diagram of the inner electrode structure shown.

[0055] Figure 2 A structural diagram of a device capable of measuring transformer oil conductivity under high field strength conditions provided by an embodiment of the present invention.

[0056] Figure 3 A structural diagram of a high-voltage electrode cup provided in an embodiment of the present invention.

[0057] Figure 4 for Figure 3 Schematic diagram of the outer electrode structure of the high-voltage electrode cup shown.

[0058] In the figure: 1 is a DC high-voltage power supply, 2 is a high-voltage electrode cup, 3 is an electromagnetic heating system, 4 is a control system, 5 is an inner electrode, 6 is an outer electrode, 7 is an inner electrode electric heating rod, 8 is an inner electrode temperature sensor, 9 is an outer electrode temperature sensor, 10 is an electromagnetic coil, 11 is a micro-current measurement plug, 12 is a high-voltage electric plug, 13 is a high-precision micro-ammeter, 14 is a touch screen liquid crystal display, 15 is an oil temperature sensor, 16 is an elastic measuring contact, 17 is an insulating positioning ring, 18 is a shielding electrode, 19 is an insulating ring, 20 is a shielding cover, 21 is a fixing bolt, and 22 is an insulating fastening cover. DETAILED DESCRIPTION

[0059] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0060] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of devices and methods consistent with some aspects of the present invention as detailed in the appended claims.

[0061] The inventor found that the electrode cup of the instrument used in the first test method provided in the prior art is a concentric circle electrode that forms an electric field type similar to the actual working condition of the converter transformer, but the electric field strength used is only 0.25kV / mm, which is far from the working condition of the 2kV / mm-4kV / mm electric field strength that the transformer oil in the converter transformer is subjected to. Since the design of the electrode cup in the instrument cannot withstand high voltage, the conductivity of the transformer oil under high electric field strength cannot be measured. The other test method uses a flat three-terminal high-voltage electrode cup. Although it can be tested under high electric field strength, this method measures the conductivity under the flat electric field, which is completely different from the concentric ring electric field type that the transformer oil in the converter transformer is mainly subjected to. In addition, the device is large in size and difficult to be miniaturized, and cannot be used as a factory inspection instrument for transformer oil products. Based on this, the inventor provides a high-voltage electrode cup, a device for measuring the conductivity of transformer oil under high field strength conditions, and a method for measuring the conductivity of transformer oil under high field strength conditions.

[0062] Embodiment 1

[0063] Reference Figure 1 As shown, an embodiment of the present invention provides a device capable of measuring the conductivity of transformer oil under high field strength conditions, the device comprising: a high-voltage electrode cup 2, a DC high-voltage power supply 1, an electromagnetic heating system 3 and a control system 4. Among them:

[0064] The high voltage electrode cup 2 is embedded in the electromagnetic heating system 3;

[0065] The control system 4 is connected to the micro-current measuring plug 11 of the high-voltage electrode cup 2, and is used to measure the micro-current passing through the transformer oil in the high-voltage electrode cup 2;

[0066] The DC high voltage power supply 1 is connected to the outer electrode 6 of the high voltage electrode cup 2;

[0067] The control system 4 is connected to the DC high voltage power supply 1 and is used to control the voltage and polarity applied to the high voltage electrode cup 2;

[0068] The control system 4 is connected to the electromagnetic heating system 3 via an electromagnetic heating control line, and is used to control the temperature of the electromagnetic heating system 3 .

[0069] Reference Figure 2-Figure 4 As shown, the high voltage electrode cup 2 comprises: an electrode cup body (not shown in the figure), an outer electrode 6 and an insulating fastening cover 22;

[0070] The electrode cup body includes an inner electrode 5, a shielding electrode 18, an insulating positioning ring 17, a micro-current measurement plug 11, an elastic measurement contact 16, an insulating ring 19, and a shielding cover 20;

[0071] The shielding electrode 18 is disposed on the upper portion of the inner electrode 5;

[0072] The insulating positioning ring 17 is fixed around the outer wall of the shielding electrode 18;

[0073] The shielding cover 20 is fixed on the shielding electrode 18, and the bottom of the shielding cover 20 abuts against the upper part of the shielding electrode 18;

[0074] The elastic measuring contact 16 is fixed between the insulating ring 19 and the shielding electrode 18, and is connected to the inner electrode 5;

[0075] The micro-current measuring plug 11 passes through the shielding cover 20 and the insulating ring 19 to connect to the elastic measuring contact 16;

[0076] The electrode cup body and the outer electrode 6 are fixed by the insulating fastening cover 22, and the insulating fixed outer ring 17 is in contact with the inner wall of the outer electrode 6;

[0077] The outer electrode 6 and the inner electrode 5 are concentric rings, and the electrode spacing between the outer electrode 6 and the inner electrode 5 is a preset spacing.

[0078] The above-mentioned high-voltage electrode cup 2 provided in the embodiment of the present invention is a three-terminal high-voltage electrode cup, and the electrode cup body is fixed in the outer electrode 6 by an insulating fastening cover 22. Since the outer electrode 6 and the inner electrode 5 in the electrode cup body are concentric rings, the electrode spacing between the two is a preset spacing, so the electric field type formed by the concentric electrodes between the two is similar to the actual working condition of the converter transformer.

[0079] In the embodiment of the present invention, the electrode cup body of the high-voltage electrode cup 2 is fixed to the outer electrode 6 by an insulating fastening cover 22. The insulating fastening cover 22 insulates and protects the outer electrode 6 and the electrode cup body to avoid surface discharge, thereby improving the insulation performance of the high-voltage electrode cup 2, so that the high-voltage electrode cup 2 can meet the insulation requirements of withstanding high voltage.

[0080] In the embodiment of the present invention, the outer electrode 6 of the high-voltage electrode cup 2 and the inner electrode 5 in the electrode cup body are concentric rings, and the electrode spacing between the two is a preset spacing. The concentric rings form a concentric ring electric field through the high voltage provided by the DC high-voltage power supply 1, which completely simulates the electric field type that the transformer oil in the converter transformer is mainly subjected to, making the measurement result more reliable.

[0081] In a specific embodiment, the electrode spacing between the inner electrode 5 and the outer electrode 6 of the high-voltage electrode cup 2 is 2mm±0.05mm, the nominal capacitance value of the empty cup is 60±1pF, the insulation resistance of the empty cup is greater than 3×1012Ω and the concentric deviation is less than 0.05mm, thereby improving the measurement accuracy of the high-voltage electrode cup 2.

[0082] In the embodiment of the present invention, the shielding electrode 18 of the high-voltage electrode cup 2 is arranged on the upper part of the inner electrode 5, which can prevent electromagnetic interference and arcing, and ensure the accuracy and reliability of data collection during the test process of measuring the conductivity of transformer oil.

[0083] In the embodiment of the present invention, the insulating positioning ring 17 of the high-voltage electrode cup 2 is fixed to the outer wall of the shielding electrode 18 and contacts the inner wall of the outer electrode 6. The insulating positioning ring 17 needs to have a sufficient diameter to cooperate with the outer electrode 6 to improve the insulation strength of the high-voltage electrode cup 2, so that the insulating positioning ring 17 can withstand a high voltage exceeding ±10kV, so that the high-voltage electrode cup can provide the same operating conditions as the 2kV / mm-4kV / mm electric field strength that the transformer oil in the converter transformer withstands.

[0084] In a specific embodiment, the insulating positioning ring 17 can be made of insulating materials such as ceramics, glass or PEEK (polyetheretherketone). The insulating material can effectively isolate the current and protect the measuring device from electromagnetic interference.

[0085] In a specific embodiment, referring to Figure 4 As shown, the shielding cover 20 is fixed on the shielding electrode 18 by fixing bolts 21, and the bottom of the shielding cover 20 abuts against the upper part of the shielding electrode 18 to shield the signal, improve the measurement accuracy, and ensure the stability of the measured current value.

[0086] In the embodiment of the present invention, the elastic measuring contact 16 of the high-voltage electrode cup 2 is fixed between the insulating ring 19 and the shielding electrode 18, and is connected to the inner electrode 5. The micro-current measuring plug 11 passes through the shielding cover 20 and the insulating ring 19 to connect the elastic measuring contact 16, thereby establishing the connection between the micro-current measuring plug 11 and the inner electrode 5, ensuring the insulation performance of the inner electrode 5 and the micro-current measuring plug 11, and realizing the measurement of the transformer oil current. The shielding cover 20 is connected to the micro-current measuring plug 11, and the structure including the shielding electrode 18 and the inner electrode 5 is shielded for signal, ensuring the stability and accuracy during the test measurement.

[0087] In the embodiment of the present invention, the high voltage electrode cup 2 connects the inner electrode 5 with the micro-current measuring plug 11 through the elastic measuring contact 16, and adopts a soft connection method for the purpose of facilitating assembly. When fixing the elastic measuring contact 16, attention should be paid to whether the contact is fastened to avoid problems such as poor contact or looseness affecting the measurement results.

[0088] In a specific embodiment, referring to Figure 4 As shown, the electrode cup body also includes an inner electrode temperature sensor 8 and an inner electrode electric heating rod 7. The inner electrode temperature sensor 8 and the inner electrode electric heating rod 7 are arranged on the inner electrode 5. The inner electrode electric heating rod 7 is used to heat the inner electrode 5 and provide the required temperature of the inner electrode 5. The inner electrode temperature sensor 8 is used to monitor the temperature of the inner electrode 5. The inner electrode temperature sensor 8 and the inner electrode electric heating rod 7 are connected to the control system to form an inner electrode 5 heating device of the high-voltage electrode cup 2, which is used to control the temperature of the inner electrode 5 in the high-voltage electrode cup 2 so that the transformer oil is at the required temperature for the test.

[0089] In a specific embodiment, referring to Figure 2 As shown, the high-voltage electrode cup 2 further includes an external electrode temperature sensor 9, which is disposed in a socket on the side wall of the external electrode 6 to collect the temperature of the external electrode 6.

[0090] In a specific embodiment, referring to Figure 1 As shown, the high-voltage electrode cup 2 also includes a high-voltage electrical plug 12 , which is disposed on the outer electrode 6 and is used to connect the DC high-voltage power supply 1 and the outer electrode 6 .

[0091] In a specific embodiment, referring to Figure 1 As shown, the electromagnetic heating system 3 includes an electromagnetic coil 10. When the high-voltage electrode cup 2 is embedded in the electromagnetic heating system 3, the electromagnetic heating system 3 converts the electric energy provided by the DC high-voltage power supply 1 into heat energy by using the electromagnetic induction principle, provides a reasonable transformer oil temperature for the high-voltage electrode cup 2, and controls the transformer oil to remain stable at a certain set temperature.

[0092] In this specific embodiment, the DC high-voltage power supply 1 can be a ±12kV DC high-voltage power supply 1, which is connected to the high-voltage electric plug 12 of the high-voltage electrode cup 2 through the high-voltage power supply output line to provide the required high field strength environment for the high-voltage electrode cup 2 to measure the oil conductivity. The high-voltage electric plug 12 is arranged on the outer electrode 6.

[0093] In a specific embodiment, the control system 4 includes a high-precision micro-ammeter 13, which is connected to the micro-current measuring plug 11 of the high-voltage electrode cup 2 and is used to measure the micro-current passing through the transformer oil in the high-voltage electrode cup 2. The micro-current test range of the high-precision micro-ammeter 13 is 1×10-13A to 1×10-2A, and the resolution is 1×10-13A. The smaller the resolution, the higher the measurement accuracy, and the more accurate the transformer oil measurement result.

[0094] In a specific embodiment, referring to Figure 1 As shown, the control system 4 also includes an integrated control box (not shown in the figure) and a touch LCD display 14. The integrated control box is connected to the high-voltage DC power supply 1, and is used to set the DC high voltage value and the polarity of the DC high voltage, and to set the charging time and the discharging time. The integrated control box is connected to the oil temperature sensor 15, the inner electrode temperature sensor 8, the inner electrode electric heating rod 7 and the outer electrode temperature sensor 9 of the high-voltage electrode cup 2, and is connected to the electromagnetic coil 10, wherein the oil temperature sensor 15 converts the measured temperature of the transformer oil into an electrical signal and sends it to the integrated control box. The integrated control box monitors the experimental temperature in real time according to the received oil temperature signal. The function of setting and controlling the test temperature is realized. The integrated control box is connected to the high-precision microammeter 13 to collect and record the microcurrent of the transformer oil in the high-voltage electrode cup 2. The touch screen LCD display 14 is connected to the integrated control box, and can input experimental parameters and display control parameters and experimental test results in real time.

[0095] In order to make a clearer description of the device for measuring the conductivity of transformer oil under high field strength provided by the embodiment of the present invention, the present invention is further described in detail below by taking the test process of measuring the conductivity of transformer oil (measured in the actual working process) of the KI50GX transformer when it is running with the device as an example. The test process specifically includes:

[0096] Step 1, disassembling and cleaning the high-voltage electrode cup 2: remove the insulating fastening cover 22, take out the electrode cup body from the outer electrode 6, and first use cleaning gasoline (petroleum ether or n-heptane) to clean it. Cleaning gasoline can effectively remove the dirt on the surface of the high-voltage electrode cup. After that, use detergent to wash (or boil in 5%-10% trisodium phosphate solution for 5 minutes) to further remove the dirt on the surface of the high-voltage electrode cup 2. Then rinse with tap water until neutral to ensure that the measurement results are not interfered by other factors. Finally, wash with distilled water 2-3 times to complete the disassembly and cleaning of the high-voltage electrode cup 2.

[0097] Step 2, drying the high-voltage electrode cup 2: Place the cleaned components of the high-voltage electrode cup 2 in a 105℃-110℃ drying oven and dry for 2h-4h. Take them out and place them in a glass dryer to cool to room temperature (do not touch them directly with your hands during operation, wear clean cloth gloves to avoid contamination of the high-voltage electrode cup 2 and thus affect the measurement results).

[0098] Step 3, assemble the high-voltage electrode cup 2, assemble the components in the reverse order of disassembly, and then place the inner electrode 5 in the outer electrode 6.

[0099] Step 4, check the high-voltage electrode cup 2: Use a capacitance meter to confirm that the positive and negative deviation between the measured value of the empty cup capacitance of the high-voltage electrode cup and the nominal value is no more than 2%, and confirm that the insulation resistance of the empty cup is greater than 3×1012Ω.

[0100] Step 5, turn on the instrument and use the control system to set the test temperature, electric field strength, polarity and electrification time.

[0101] Step 6, injecting transformer oil: Mix the test sample evenly (try to avoid generating bubbles), and slowly inject an appropriate amount of the sample into the cleaned test high-voltage electrode cup 2.

[0102] Step 7, install the high-voltage electrode cup 2 into the electromagnetic heating system 3, connect the wires, and install the fasteners.

[0103] Step 8, the control system 4 controls the heating of the high-voltage electrode cup 2 and detects the oil temperature in the high-voltage electrode cup 2. When the oil temperature reaches the test temperature and remains constant for a preset time, the high-voltage electrode cup 2 is pressurized, charged and measured by a high-voltage DC power supply, and the test results are recorded.

[0104] Step 9, empty the high-voltage electrode cup 2, re-execute the above test process for parallel testing, and record the results of the parallel testing. In normal testing, if the oil tested in the previous test is of the same type and qualified, then in this test, the high-voltage electrode cup 2 can be "injected with an appropriate amount of the tested sample each time and shaken for 1 minute to empty, and repeated 2-3 times"; if the sample tested in the previous test is not of the same type or unqualified, then in this test, the high-voltage electrode cup 2 is cleaned according to step 1.

[0105] Step 10, compare the two measurement results. The difference between the two results should not exceed 35% of the lower of the two values. Otherwise, continue to measure the sample until the difference between two adjacent readings does not exceed 35% of the lower of the two values. Only then is the test valid.

[0106] Step 11, calculate the experimental results based on the experimental data:

[0107] After obtaining the applied DC voltage value and the measured sample current value, the conductivity is calculated using the following formula:

[0108] σ=I / K·U

[0109] In the formula: σ represents conductivity; K represents empty electrode constant; I represents the measured sample current value; U represents the applied DC voltage value; wherein, K=0.113Ca, Ca represents the empty cup electrode capacitance value of the high voltage electrode cup 2.

[0110] The specific test results are shown in Table 1. The device successfully completed the measurement of transformer oil conductivity under high field strength conditions.

[0111] Table 1 Test results of conductivity of K150GX transformer oil operating oil at different electric field strengths

[0112]

[0113] Based on the above-mentioned device for measuring the conductivity of transformer oil under high-field strength electric field, the electric field strength used can meet the electric field strength of 2kV / mm to 4kV / mm that the transformer oil in the converter transformer is borne, can withstand high voltage, and directly and reliably measure the conductivity of transformer oil under high-field strength conditions. Since the high-voltage electrode cup 2 is an electric field type formed by concentric circular electrodes, which is similar to the actual working condition of the converter transformer, and the volume of the high-voltage electrode cup 2 is small, the device for measuring the conductivity of transformer oil under high-field strength electric field using the high-voltage electrode cup 2 can be miniaturized, so that the device can be directly used as a factory inspection instrument for transformer oil products, providing a basis for the design and oil selection of converter transformers and the product development, quality control and factory inspection of converter transformer oil.

[0114] Embodiment 2

[0115] Based on the same inventive concept, the embodiment of the present invention further provides a high voltage electrode cup 2, referring to Figure 2-Figure 4 As shown, the high voltage electrode cup 2 comprises: an electrode cup body (not shown in the figure), an outer electrode 6 and an insulating fastening cover 22;

[0116] The electrode cup body includes an inner electrode 5, a shielding electrode 18, an insulating positioning ring 17, a micro-current measurement plug 11, an elastic measurement contact 16, an insulating ring 19, and a shielding cover 20;

[0117] The shielding electrode 18 is disposed on the upper portion of the inner electrode 5;

[0118] The insulating positioning ring 17 is fixed around the outer wall of the shielding electrode 18;

[0119] The shielding cover 20 is fixed on the shielding electrode 18, and the bottom of the shielding cover 20 abuts against the upper part of the shielding electrode 18;

[0120] The elastic measuring contact 16 is fixed between the insulating ring 19 and the shielding electrode 18, and is connected to the inner electrode 5;

[0121] The micro-current measuring plug 11 passes through the shielding cover 20 and the insulating ring 19 to connect to the elastic measuring contact 16;

[0122] The electrode cup body and the outer electrode 6 are fixed by the insulating fastening cover 22, and the insulating fixed outer ring 17 is in contact with the inner wall of the outer electrode 6;

[0123] The outer electrode 6 and the inner electrode 5 are concentric rings, and the electrode spacing between the outer electrode 6 and the inner electrode 5 is a preset spacing.

[0124] The high-voltage electrode cup 2 is characterized in that the electrode cup body further comprises: an inner electrode temperature sensor 8 and an inner electrode electric heating rod 7;

[0125] The inner electrode temperature sensor 8 and the inner electrode electric heating rod 7 are arranged on the inner electrode 5 .

[0126] The high voltage electrode cup 2 is characterized in that it also includes an external electrode temperature sensor 9;

[0127] The side wall of the outer electrode 6 is provided with an insertion hole, and the outer electrode temperature sensor 9 is arranged in the insertion hole.

[0128] The high-voltage electrode cup 2 is characterized in that it also includes a high-voltage electrical plug 12;

[0129] The high voltage electrical plug 12 is disposed on the outer electrode 6 .

[0130] The high-voltage electrode cup 2 is characterized in that the electrode spacing between the inner electrode 5 and the outer electrode 6 is 2 mm±0.05 mm, and the concentricity deviation between the inner electrode 5 and the outer electrode 6 is less than 0.05 mm.

[0131] The high-voltage electrode cup 2 is characterized in that the empty cup nominal capacitance value of the high-voltage electrode cup 2 is 60±1pF, and the empty cup insulation resistance is greater than 3×1012Ω.

[0132] The high-voltage electrode cup 2 is characterized in that the insulation strength of the insulating positioning ring 17 is sufficient to withstand a high voltage of ±10kV.

[0133] The high-voltage electrode cup 2 provided in the embodiment of the present invention fixes the electrode cup body in the outer electrode 6 through the insulating fastening cover 22. Since the outer electrode 6 and the inner electrode 5 in the electrode cup body are concentric rings, the electrode spacing between the two is a preset spacing. Therefore, the electric field type formed by the concentric electrodes between the two is similar to the actual working condition of the converter transformer. Since the insulating positioning ring 17 is fixed on the shielding electrode 18, the micro-current measurement plug 11 passes through the shielding cover 20 and the insulating ring 19 and is connected to the inner electrode 5 via the elastic measurement contact 16, thereby ensuring the insulation performance of the inner electrode 5 and the micro-current measurement plug 11, and the insulating positioning ring 17 is in contact with the inner side wall of the outer electrode 6, thereby increasing the insulation distance and improving the insulation strength, avoiding surface discharge, so that the high-voltage electrode cup 2 can meet the insulation requirements of withstanding high voltage; it is connected to the micro-current measurement plug 11 through the shielding cover 20, and the structure including the shielding electrode and the inner electrode 5 is signal shielded to ensure stability and accuracy during test measurement.

[0134] The high-voltage electrode cup 2 provided in the embodiment of the present invention can be applied to a device for measuring the conductivity of transformer oil under a high-field strength electric field, so that the electric field strength used by the device can meet the electric field strength of 2kV / mm to 4kV / mm that the transformer oil in the converter transformer is borne by, and can withstand high voltage, and directly and reliably measure the conductivity of the transformer oil under high field strength conditions. Since the high-voltage electrode cup 2 is an electric field type formed by concentric circle electrodes, which is similar to the actual working condition of the converter transformer, and the volume of the high-voltage electrode cup 2 is small, it is conducive to the miniaturization of the measuring device using the high-voltage electrode cup 2, so that the device can be directly used as a transformer oil product factory inspection instrument, providing a basis for the design and oil selection of converter transformers and the product development, quality control and factory inspection of converter transformer oil.

[0135] Embodiment 3

[0136] Based on the same inventive concept, an embodiment of the present invention further provides a method for measuring transformer oil conductivity under high field strength conditions, the method comprising the following steps:

[0137] Disassemble and clean the high-voltage electrode cup 2 and dry, assemble and inspect it;

[0138] Turn on the control system and set the test temperature, electric field strength, polarity and electrification time;

[0139] Mix the test sample evenly and slowly inject it into the high voltage electrode cup 2;

[0140] Installing the high voltage electrode cup 2 into the electromagnetic heating system 3;

[0141] The control system 4 controls the heating of the high-voltage electrode cup 2, and after detecting that the oil temperature in the high-voltage electrode cup 2 reaches the test temperature, the test temperature is kept constant for a preset time, and the high-voltage electrode cup 2 is pressurized, charged and measured by the high-voltage DC power supply 1 to obtain the test result;

[0142] The oil cup of the high-voltage electrode cup 2 is drained, and the above test process is executed again to perform parallel tests until the results of two adjacent tests meet the preset conditions, and the conductivity is calculated.

[0143] In a specific embodiment, the method further comprises:

[0144] After obtaining the applied DC voltage value and the measured sample current value, the conductivity is calculated using the following formula:

[0145] σ=I / K·U

[0146] In the formula: σ represents conductivity; K represents empty electrode constant; I represents the measured sample current value; U represents the applied DC voltage value; wherein, K=0.113Ca, Ca represents the empty cup electrode capacitance value of the high voltage electrode cup 2.

[0147] The specific implementation process of the method for measuring the conductivity of transformer oil under high field strength conditions provided in the third embodiment of the present invention can refer to the detailed description of the experimental process of using the device for measuring the conductivity of transformer oil under high field strength conditions to measure the conductivity of transformer oil at different electric field strengths when the KI50GX transformer is running in the first embodiment, which will not be repeated here.

[0148] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0149] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0150] In this document, relational terms such as first and second, etc. are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. The orientation or position relationship indicated by the terms "upper", "lower", etc. is based on the orientation or position relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0151] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict. The present invention is not limited to any single aspect, any single embodiment, or any combination and / or permutation of these aspects and / or embodiments. Each aspect and / or embodiment of the present invention can be used alone, or in combination with one or more other aspects and / or other embodiments.

[0152] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A high voltage electrode cup, characterized in that: include: Electrode cup body, outer electrode and insulating fastening cover; The electrode cup body comprises an inner electrode, a shielding electrode, an insulating positioning ring, a micro-current measurement plug, an elastic measurement contact, an insulating ring, and a shielding cover; The shielding electrode is disposed on the upper portion of the inner electrode; The insulating positioning ring is fixed around the outer side wall of the shielding electrode; The shielding cover is fixed on the shielding electrode, and the bottom of the shielding cover abuts against the upper part of the shielding electrode; The elastic measuring contact is fixed between the insulating ring and the shielding electrode, and is connected to the inner electrode; The micro-current measurement plug passes through the shielding cover and the insulating ring to connect the elastic measurement contact; The electrode cup body and the outer electrode are fixed by the insulating fastening cover, and the insulating fixed outer ring is in contact with the inner side wall of the outer electrode; The outer electrode and the inner electrode are concentric rings, and the electrode spacing between the outer electrode and the inner electrode is a preset spacing.

2. The high voltage electrode cup according to claim 1, characterized in that: The electrode cup body also includes: an inner electrode temperature sensor and an inner electrode electric heating rod; The inner electrode temperature sensor and the inner electrode electric heating rod are arranged on the inner electrode.

3. The high voltage electrode cup according to claim 1, characterized in that: Also included is an outer electrode temperature sensor; The side wall of the outer electrode is provided with an insertion hole, and the outer electrode temperature sensor is arranged in the insertion hole.

4. The high voltage electrode cup according to claim 1, characterized in that: It also includes a high voltage electrical plug; The high voltage electric plug is arranged on the outer electrode.

5. The high voltage electrode cup according to claim 1, characterized in that: The electrode spacing between the inner electrode and the outer electrode is 2 mm±0.05 mm, and the concentricity deviation between the inner electrode and the outer electrode is less than 0.05 mm.

6. The high voltage electrode cup according to claim 1, characterized in that: The empty cup nominal capacitance value of the high voltage electrode cup is 60±1pF, and the empty cup insulation resistance is greater than 3×1012Ω.

7. The high voltage electrode cup according to claim 1, characterized in that: The insulation strength of the insulating positioning ring is sufficient to withstand a high voltage of ±10kV.

8. A device capable of measuring the electrical conductivity of transformer oil under high field strength conditions, characterized in that: include: The high-voltage electrode cup, DC high-voltage power supply, electromagnetic heating system and control system according to any one of claims 1 to 7; The high-voltage electrode cup is embedded in the electromagnetic heating system; The control system is connected to the micro-current measuring plug and is used to measure the micro-current passing through the transformer oil in the high-voltage electrode cup; The DC high voltage power supply is connected to the outer electrode of the high voltage electrode cup; The control system is connected to the DC high voltage power supply and is used to control the voltage and polarity applied to the high voltage electrode cup; The control system is connected to the electromagnetic heating system through an electromagnetic heating control line and is used to control the temperature of the electromagnetic heating system.

9. The device according to claim 8, characterized in that The electromagnetic heating system comprises: an electromagnetic coil; When the high-voltage electrode cup is embedded in the electromagnetic heating system, the electromagnetic coil is distributed around the high-voltage electrode cup.

10. The device of claim 9, wherein the control system comprises a high-precision micro-ammeter; The high-precision micro-ammeter is connected to the micro-current measuring plug of the high-voltage electrode cup and is used to measure the micro-current passing through the transformer oil in the high-voltage electrode cup.

11. The device as claimed in claim 10, wherein the microcurrent test range of the high-precision microammeter is 1×10-13A to 1×10-2A, and the resolution is 1×10-13A.

12. The device of claim 10, wherein the control system further comprises: Integrated control box; The integrated control box is connected to the high-voltage electrode cup oil temperature sensor, the inner electrode temperature sensor, the inner electrode electric heating rod and the outer electrode temperature sensor, and is connected to the electromagnetic coil for setting and controlling the test temperature; The integrated control box is connected to a high-precision micro-ammeter for collecting and recording the micro-current of the transformer oil in the high-voltage electrode cup; The integrated control box is connected to the high-voltage DC power supply and is used to set the DC high voltage value and the polarity of the DC high voltage, and to set the charging time and the discharging time.

13. The apparatus of claim 12, wherein the control system further comprises the touch screen liquid crystal display; The touch screen liquid crystal display is connected to the integrated control box and is used for inputting experimental parameters and displaying real-time control parameters and experimental results.

14. A method for measuring the electrical conductivity of transformer oil under high field strength conditions, characterized in that: include: Disassemble and clean the high-voltage electrode cup and dry, assemble and inspect it; Turn on the control system and set the test temperature, electric field strength, polarity and electrification time; Mix the test sample evenly and slowly inject it into the high voltage electrode cup; Installing the high voltage electrode cup into an electromagnetic heating system; The control system controls the heating of the high-voltage electrode cup, and after detecting that the oil temperature in the high-voltage electrode cup reaches the test temperature, the test temperature is kept constant for a preset time, and the high-voltage electrode cup is pressurized, charged and measured by a high-voltage DC power supply to obtain a test result; The oil cup of the high-voltage electrode cup is drained, and the above test process is executed again to perform parallel tests until the results of two adjacent tests meet the preset conditions, and the conductivity is calculated.

15. The method according to claim 14, characterized in that Also includes: After obtaining the applied DC voltage value and the measured sample current value, the conductivity is calculated using the following formula: σ=I / K·U In the formula: σ represents conductivity; K represents the empty electrode constant; I represents the measured sample current value; U represents the applied DC voltage value; among them, K=0.113Ca, Ca represents the empty cup electrode capacitance value of the high voltage electrode cup.

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