Partial discharge detection and defect identification system and method for tube-type GIS insulating pull rod

Abstract

The application relates to a partial discharge detection and defect identification system and method for a tubular GIS insulating pull rod, which comprises a high-voltage power supply, a partial discharge collection device and a detection electrode system; the annular high-voltage electrode of the detection electrode system is sleeved outside the tubular GIS insulating pull rod, the columnar ground electrode is installed inside the tubular GIS insulating pull rod and is connected to the partial discharge collection device through a wire; the partial discharge collection device performs defect detection and identification according to the received data. The application has the characteristics of high detection precision, convenient use and the like, solves the problems that in the traditional method, due to the continuous reduction of the electric field strength along the axial direction, the pull rod partial discharge characteristics are not obvious, latent defects are difficult to detect, and interference is prone to occur in the partial discharge detection, and can detect defects and classify defects of the tubular GIS insulating pull rod generated in the production and use process, and evaluate the durability of the fatigue-damaged insulating pull rod.

Description

Technical Field

[0001] This invention belongs to the field of high-voltage power distribution technology, and relates to high-voltage GIS insulated tie rods, particularly a partial discharge detection and defect identification system and method for tubular GIS insulated tie rods. Background Technology

[0002] High-voltage GIS is a high-voltage power distribution device that uses SF6 gas as the insulating medium and is composed of high-voltage electrical equipment such as circuit breakers and disconnectors. Due to its compact structure, high reliability, and convenient maintenance, high-voltage GIS has become the best equipment for power conversion in ultra-high voltage and extra-high voltage substations and is widely used in power transmission and transformation projects in my country.

[0003] Insulating tie rods are key components in high-voltage gas-insulated metal-enclosed switchgear (GIS) circuit breakers and disconnectors, used to transmit motion from the grounded part to the high-potential part to achieve electrical connection switching. Because insulating tie rods need to withstand break-point recovery voltage and frequent mechanical operations, stringent requirements are placed on the comprehensive performance of the insulation materials. In recent years, multiple internal breakdown and disintegration faults of insulating tie rods have occurred during field commissioning or operation of ultra-high voltage / extra-high voltage GIS, becoming a significant factor seriously threatening the safe and reliable operation of power grid equipment. Disassembly and analysis of faulty tie rods revealed that some fault characteristics mainly included: interlayer breakdown channels within the composite material of the insulating tie rod, burning marks on the surface and inside of the insulating tie rod, and localized penetrating ablation along the radial direction of the rod wall. Fault process analysis and simulation experiments confirmed that all of these faults were caused by defects inside the insulating tie rod. Furthermore, in the traditional partial discharge testing method using electrodes placed at both ends of the insulating tie rod, the electric field strength continuously decreases along the axial direction, resulting in indistinct partial discharge characteristics and making it difficult to detect latent defects. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and propose a partial discharge detection and defect identification system and method for tubular GIS insulated tie rods, which solves the problem that latent defects are difficult to detect because the partial discharge characteristics of the tie rods are not obvious due to the continuous decrease of electric field strength along the axial direction.

[0005] The present invention solves the existing technical problems by adopting the following technical solution:

[0006] A partial discharge detection and defect identification system for tubular GIS insulated tie rods includes a high-voltage power supply, a partial discharge acquisition device, and a detection electrode system;

[0007] The high-voltage power supply includes a partial discharge-free transformer, a voltage regulator, a current-limiting resistor, and a voltage divider. The partial discharge-free transformer is connected to the voltage regulator. The output terminal of the partial discharge-free transformer outputs a high-voltage power supply and is connected to one end of the current-limiting resistor. The other end of the current-limiting resistor is connected to one end of the voltage divider and the high-voltage electrode of the detection electrode system. The voltage divider measures the applied voltage in real time and provides a phase synchronization signal.

[0008] The detection electrode system consists of a ring-column electrode and a tubular GIS insulating rod. The ring-column electrode is composed of a ring-shaped high-voltage electrode and a columnar ground electrode. The ring-shaped high-voltage electrode is fitted outside the tubular GIS insulating rod, and the columnar ground electrode is installed inside the tubular GIS insulating rod and connected to the partial discharge acquisition device through a wire.

[0009] The partial discharge acquisition device includes an HFCT sensor, a signal processor, and a test host. The HFCT sensor has a wire concentrically passing through a cylindrical ground electrode to acquire the discharge pulse current in real time. The signal processor is connected to the resistor-capacitor voltage divider and the HFCT sensor, synchronizes the phase of the discharge pulse current with the applied voltage, and transmits the processed data to the test host. The test host performs defect detection and identification based on the received data.

[0010] Furthermore, the ring-column electrode is composed of a copper ring-shaped high-voltage electrode and a copper columnar ground electrode.

[0011] Furthermore, the detection electrode system is installed in silicone oil within the oil tank.

[0012] Furthermore, the tubular GIS insulating tie rod is installed inside the oil tank via a sample bracket at the bottom of the oil tank, and the columnar ground electrode is installed inside the tubular GIS insulating tie rod via an insulating bracket.

[0013] Furthermore, the high-voltage power supply, partial discharge acquisition equipment, detection electrode system, and their associated equipment are all connected via shielded wires.

[0014] Furthermore, the partial discharge-free transformer is a 0-100kV transformer, the current-limiting resistor is a 2MΩ current-limiting resistor, and the voltage divider is a 1000:1 RC voltage divider.

[0015] A method for partial discharge detection and defect identification system for tubular GIS insulated tie rods includes the following steps:

[0016] Step 1: Clean the inner and outer walls of the GIS insulating tie rod to be tested.

[0017] Step 2: Immerse the GIS insulating rod to be tested into an oil tank containing silicone oil at a certain angle;

[0018] Step 3: Place the ring-cylinder electrode into the oil tank and install it in the test area of ​​the tubular GIS insulating tie rod to be tested;

[0019] Step 4: Connect the ring-shaped high-voltage electrode to the high-voltage power supply, and pass the cylindrical ground electrode through the HFCT sensor to the signal processor via a wire; adjust the voltage regulator to control the applied voltage, and then turn on the signal processor to collect partial discharge characteristics in real time, and observe the partial discharge situation in real time on the test host.

[0020] Step 5: After the test area is completed, adjust the voltage regulator to zero and turn off the voltage regulator and signal processor.

[0021] Step 6: Move the ring-pillar electrode to the next test area, return to step 3 and repeat steps 3-6.

[0022] Furthermore, in step 3, the installation process of the ring-column electrode is carried out entirely below the surface of the oil tank. The ring-shaped high-voltage electrode is fitted onto the outside of the tubular GIS insulating rod, and the columnar ground electrode is installed inside the tubular GIS insulating rod, with the ring-shaped high-voltage electrode and the columnar ground electrode strictly aligned.

[0023] The advantages and positive effects of this invention are:

[0024] This invention features a rational design, integrating a ring-cylinder electrode with a tubular GIS insulating tie rod. The ring-cylinder electrode can move flexibly between different positions on the insulating tie rod, enabling defect detection and identification in different areas. This solves the problem in traditional methods where the electric field strength continuously decreases along the axial direction, resulting in indistinct partial discharge characteristics and difficulty in detecting latent defects. Furthermore, the use of an oil-immersion acquisition method solves the interference problem that easily occurs in partial discharge detection. It can perform real-time synchronous testing of the partial discharge characteristics of insulating tie rods with different defects, and features high detection accuracy and ease of use. It can detect and classify defects generated during the production and use of composite material insulating tie rods for GIS, and evaluate the durability of fatigue-damaged insulating tie rods. Attached Figure Description

[0025] Figure 1 This is a diagram of the ring-pillar electrode structure of the present invention;

[0026] Figure 2 This is a schematic diagram of the detection electrode system of the present invention;

[0027] Figure 3 This is a schematic diagram of the connection of the tubular GIS insulated tie rod partial discharge detection and defect identification system of the present invention;

[0028] Figure 4 This is a diagram showing the results of synchronous testing of the partial discharge characteristics of a defective insulating tie rod according to the present invention.

[0029] In the diagram, 1-no partial discharge transformer, 2-voltage regulator, 3-current limiting resistor (2MΩ), 4-voltage divider, 5-signal processor, 6-HFCT sensor, 7-test host, 8-detection electrode system. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to the accompanying drawings.

[0031] A partial discharge detection and defect identification system for tubular GIS insulated tie rods, such as Figure 3 As shown, the system is composed of a high-voltage power supply, a partial discharge acquisition device and a detection electrode system (8). This detection and defect identification system can perform real-time synchronous testing on the partial discharge characteristics of tubular GIS insulated rods, thereby realizing the function of detecting and identifying latent defects in insulated rods.

[0032] The high-voltage power supply includes a 0-100kV partial discharge-free transformer (1), a voltage regulator (2), a 2MΩ current-limiting resistor (3), and a 1000:1 RC divider (4). The 0-100kV partial discharge-free transformer (1) is connected to the voltage regulator (2) to output a 0-100kV high-voltage power supply. The output terminal of the 0-100kV partial discharge-free transformer (1) is connected to one end of the 2MΩ current-limiting resistor (3). The 2MΩ current-limiting resistor (3) is used to prevent overcurrent and avoid damage to the system from overcurrent. The other end of the 2MΩ current-limiting resistor (3) is connected to one end of the 1000:1 RC divider (4) and one end of the detection electrode system. The 1000:1 RC divider (4) is used to measure the applied voltage in real time and provide a phase synchronization signal to the signal processor (5).

[0033] The partial discharge acquisition device includes an HFCT sensor (6), a signal processor (5), and a test host (7). The HFCT sensor (6) is concentrically connected to the ground wire of the detection electrode system to collect the discharge pulse current in real time and transmit it to the signal processor (5). The signal processor (5) is connected to a 1000:1 resistor-capacitor voltage divider (4) and the HFCT sensor (6) to synchronize the phase of the discharge pulse current with the applied voltage and transmit the processed data to the test host (7). The test host (7) performs defect detection and identification based on the received data.

[0034] All the above devices are connected by wires, and the wires are equipped with shielding devices to prevent ambient current from affecting the test results.

[0035] like Figure 2 As shown, the detection electrode system (8) consists of a ring-pillar electrode and a tubular GIS insulating rod, the insulating rod being made of composite material. Figure 1As shown, the ring-column electrode consists of a copper ring-shaped high-voltage electrode and a copper columnar ground electrode. The copper ring-shaped high-voltage electrode is fitted onto the outside of the insulating rod, and the copper columnar ground electrode is installed inside the insulating rod. To ensure better fit of the ring-column electrode to the surface of the insulating rod, both the copper ring-shaped high-voltage electrode and the copper columnar ground electrode have undergone mirror polishing.

[0036] During the testing process, the detection electrode system (8) requires immersing the ring-column electrode and the composite material insulating rod in silicone oil within an oil bath. Electrode installation should be completed below the oil surface to prevent gas from entering the gap between the electrode and the inner wall of the rod, thus distorting the results. Furthermore, the electrodes should be precisely aligned to ensure a uniform electric field. To prevent electrode slippage due to the insulating rod tilting after installation, a sample holder can be added to the bottom of the oil bath. An insulating support is installed inside the insulating rod to prevent the wire from contacting the inner wall of the insulating rod.

[0037] In this invention, the detection electrode system (8) adopts a specially designed ring-column electrode, which can be effectively applied to slender tubular insulating rods and can move flexibly between different positions of the insulating rod. This solves the problem that in the traditional partial discharge test method where electrodes are placed at both ends of the insulating rod, the electric field strength continuously decreases along the axial direction, resulting in indistinct partial discharge characteristics of the rod and making it difficult to detect latent defects. At the same time, the partial discharge test adopts an oil immersion acquisition method, which overcomes the problem of easy interference in partial discharge detection.

[0038] The working principle of this partial discharge detection and defect identification system is as follows: by installing ring-column electrodes on the tubular GIS insulated tie rod and applying high voltage to both ends of the electrodes, an electric field can be formed in the radial direction (thickness direction) of the insulated tie rod. If there is a defect in this part, partial discharge will be generated under the action of the electric field, and then detected by the partial discharge detection equipment. The size and type of defect are identified based on the characteristic parameters of partial discharge, such as discharge initiation voltage, discharge frequency, and average discharge quantity.

[0039] Based on the above-mentioned partial discharge detection and defect identification system for tubular GIS insulated tie rods, this invention also proposes a method for partial discharge detection and defect identification of tubular GIS insulated tie rods, comprising the following steps:

[0040] Step 1: Wipe and rinse the inner and outer walls of the insulating rod to be tested with alcohol to ensure that there are no impurities on the surface.

[0041] Step 2: Immerse the insulating rod at a certain angle into the oil tank containing silicone oil to ensure that all internal air is expelled.

[0042] Step 3: Place the ring-column electrode into the oil bath, so that... Figure 2Install the annular high-voltage electrode and the cylindrical ground electrode to the area to be measured as shown. During installation, use a calibrated device to ensure that the positive and negative electrodes are strictly aligned and that there are no air bubbles or impurities between the electrodes and the wall of the insulating rod.

[0043] Step 4: Connect the ring-shaped high-voltage electrode to the high-voltage power supply, and pass the cylindrical ground electrode concentrically through the HFCT sensor (6) to the signal processor (5) via a wire; adjust the voltage regulator (2) to control the applied voltage, and then turn on the signal processor (5) to collect partial discharge characteristics in real time, and observe the partial discharge situation in real time on the test host (7), such as... Figure 4 As shown.

[0044] Step 5: After the test area is completed, adjust the voltage regulator (2) to zero and turn off the voltage regulator (2) and signal processor (5).

[0045] Step 6: Move the ring-pillar electrode to the next test area, return to step 3 and repeat steps 3-6.

[0046] It should be emphasized that the embodiments described in this invention are illustrative rather than limiting. Therefore, this invention includes, but is not limited to, the embodiments described in the specific implementation. Any other implementations derived by those skilled in the art based on the technical solutions of this invention are also within the scope of protection of this invention.

Claims

1. A partial discharge detection and defect identification system for tubular GIS insulated tie rods, characterized in that: This includes a high-voltage power supply, partial discharge acquisition equipment, and a detection electrode system; The high-voltage power supply includes a partial discharge-free transformer, a voltage regulator, a current-limiting resistor, and a voltage divider. The partial discharge-free transformer is connected to the voltage regulator. The output terminal of the partial discharge-free transformer outputs a high-voltage power supply and is connected to one end of the current-limiting resistor. The other end of the current-limiting resistor is connected to one end of the voltage divider and the high-voltage electrode of the detection electrode system. The voltage divider measures the applied voltage in real time and provides a phase synchronization signal. The detection electrode system consists of a ring-column electrode and a tubular GIS insulating rod. The ring-column electrode is composed of a ring-shaped high-voltage electrode and a columnar ground electrode. The ring-shaped high-voltage electrode is fitted outside the tubular GIS insulating rod, and the columnar ground electrode is installed inside the tubular GIS insulating rod and connected to the partial discharge acquisition device through a wire. The partial discharge acquisition device includes an HFCT sensor, a signal processor, and a test host. The HFCT sensor has a wire that passes concentrically through a cylindrical ground electrode to acquire the discharge pulse current in real time. The signal processor is connected to the resistor-capacitor voltage divider and the HFCT sensor to synchronize the phase of the discharge pulse current with the applied voltage and transmit the processed data to the test host. The test host performs defect detection and identification based on the received data. The detection electrode system is installed in silicone oil in the oil tank; The tubular GIS insulating tie rod is installed in the oil tank through a sample bracket at the bottom of the oil tank, and the columnar ground electrode is installed inside the tubular GIS insulating tie rod through an insulating bracket.

2. The partial discharge detection and defect identification system for tubular GIS insulated tie rods according to claim 1, characterized in that: The ring-column electrode consists of a copper ring-shaped high-voltage electrode and a copper column-shaped ground electrode.

3. The partial discharge detection and defect identification system for tubular GIS insulated tie rods according to claim 1 or 2, characterized in that: The high-voltage power supply, partial discharge acquisition equipment, detection electrode system, and their associated equipment are all connected via shielded wires.

4. The partial discharge detection and defect identification system for tubular GIS insulated tie rods according to claim 1 or 2, characterized in that: The partial discharge-free transformer is a 0-100kV transformer, the current-limiting resistor is a 2MΩ current-limiting resistor, and the voltage divider is a 1000:1 RC voltage divider.

5. A method for identifying defects in a partial discharge detection and defect identification system for tubular GIS insulated tie rods as described in any one of claims 1 to 4, characterized in that: Includes the following steps: Step 1: Clean the inner and outer walls of the GIS insulating tie rod to be tested. Step 2: Immerse the GIS insulating rod to be tested into an oil tank containing silicone oil at a certain angle; Step 3: Place the ring-cylinder electrode into the oil tank and install it in the test area of ​​the tubular GIS insulating tie rod to be tested; Step 4: Connect the ring-shaped high-voltage electrode to the high-voltage power supply, and pass the cylindrical ground electrode through the HFCT sensor to the signal processor via a wire; adjust the voltage regulator to control the applied voltage, and then turn on the signal processor to collect partial discharge characteristics in real time, and observe the partial discharge situation in real time on the test host. Step 5: After the test area is completed, adjust the voltage regulator to zero and turn off the voltage regulator and signal processor. Step 6: Move the ring-pillar electrode to the next test area, return to step 3 and repeat steps 3-6.

6. The identification method of the partial discharge detection and defect identification system for tubular GIS insulated tie rods according to claim 5, characterized in that: In step 3, the installation process of the ring-column electrode is carried out entirely below the surface of the oil tank. The ring-shaped high-voltage electrode is fitted outside the tubular GIS insulating tie rod, and the columnar ground electrode is installed inside the tubular GIS insulating tie rod, with the ring-shaped high-voltage electrode and the columnar ground electrode strictly aligned.

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