Online purification device and method for insulating oil in high-voltage cable terminal

Abstract

The invention discloses an online purification device and method for insulating oil in a high-voltage cable terminal, and relates to the technical field of power grids, the online purification device comprises an intelligent monitoring unit, a circular flow unit, a purification unit and an insulating oil supplementing unit; the intelligent monitoring unit is used for monitoring the oil quality and the oil quantity of insulating oil in the cable terminal in real time, the circular flowing unit is used for promoting the insulating oil to circularly flow between the cable terminal and the purifying unit, and the purifying unit is used for purifying the insulating oil which circularly flows; the insulating oil supplementing unit is used for supplementing insulating oil into the pipeline of the circulating flow unit and the cable terminal; when the intelligent monitoring unit detects that the oil quantity in the cable terminal is smaller than a set threshold value, the insulating oil in the insulating oil supplementing unit is conveyed into the cable terminal through the circular flowing unit. According to the invention, the internal insulating oil can be purified on line without power failure, so that time and labor are saved, and the maintenance cost can be reduced.

Description

Technical Field

[0001] This invention relates to high-voltage cable termination technology, specifically to an online purification device and method for the internal insulating oil of a high-voltage cable termination. Background Technology

[0002] High-voltage cable terminals are critical components in power transmission systems, and the insulating oil filling them plays a vital role in insulation and heat dissipation. The quality of the insulating oil directly affects the safe and stable operation of the cable terminal and even the entire cable line. During long-term operation, the insulating oil gradually deteriorates due to various factors: on the one hand, external moisture may infiltrate through weak points in the seal, leading to increased water content in the oil; on the other hand, aging of internal materials, partial discharge, or overheating faults can generate tiny particulate impurities and characteristic dissolved gases such as hydrogen, methane, and acetylene. These contaminants significantly reduce the breakdown voltage and dielectric loss factor of the insulating oil, accelerate the aging of the insulation materials, and may ultimately lead to terminal insulation failure, triggering serious power accidents.

[0003] Currently, the maintenance of insulating oil inside cable terminals mainly relies on two methods: one is to periodically replace all the insulating oil, and the other is to extract the insulating oil, perform offline purification treatment, and then reinject it. Both of these traditional methods have significant drawbacks: First, they must be carried out under conditions of cable de-energization, which is not only complex and time-consuming, but also leads to power outages, resulting in huge economic and social costs; second, offline treatment is a periodic maintenance and cannot respond in real time to sudden and rapid deterioration of the insulating oil, creating maintenance blind spots; third, if not handled properly during the oil extraction and injection process, air, moisture, or new particulate contamination can easily be introduced, leading to secondary risks. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned problems and provide an online purification device for the internal insulating oil of high-voltage cable terminals. This online purification device can purify the internal insulating oil without power interruption, which not only saves time and effort, but also significantly reduces maintenance costs.

[0005] Another objective of this invention is to provide an online purification method for the insulating oil inside high-voltage cable terminals.

[0006] The objective of this invention is achieved through the following technical solution: An online purification device for insulating oil inside a high-voltage cable terminal includes an intelligent monitoring unit, a circulation unit, a purification unit, and an insulating oil replenishment unit. The intelligent monitoring unit is used to monitor the oil quality and the amount of insulating oil in the cable terminal in real time. The circulating flow unit is used to promote the circulation of insulating oil between the cable terminal and the purification unit. The purification unit is used to purify the circulating insulating oil. The insulating oil replenishment unit is used to replenish insulating oil into the pipeline of the circulation flow unit and the cable terminal. When the pipeline of the circulation flow unit is not filled with insulating oil before the purification device is started, the insulating oil in the insulating oil replenishment unit is transported to the pipeline through the circulation flow unit. When the intelligent monitoring unit detects that the amount of oil in the cable terminal is less than the set threshold, the insulating oil in the insulating oil replenishment unit is transported to the cable terminal through the circulation flow unit until the intelligent monitoring unit detects that the amount of oil in the cable terminal is greater than or equal to the set threshold.

[0007] In a preferred embodiment of the present invention, the intelligent monitoring unit includes an oil quality monitoring module and an oil quantity monitoring module. The oil quality monitoring module is located on the outside of the cable terminal and includes a humidity sensor, a particle sensor, and a gas detection module. The oil quantity monitoring module includes a pressure sensor, which is located at the top of the inner cavity of the cable terminal and is used to detect the pressure inside the cable terminal to reflect the oil quantity of the insulating oil. Through the above structure, synchronous and real-time online monitoring of key quality parameters of the insulating oil (moisture, particles, fault gases) and the oil quantity status inside the terminal (indirectly and accurately reflected by pressure) is achieved. This not only provides accurate criteria for the intelligent start and stop of the purification process, but more importantly, it can directly and sensitively sense pressure fluctuations inside the terminal caused by changes in oil quantity, providing a core feedback signal for subsequent automatic oil replenishment control, fundamentally ensuring the safety of terminal operation.

[0008] In a preferred embodiment of the present invention, the purification unit includes a microfiltration unit and an adsorption unit. The microfiltration unit is used to remove particulate impurities from the circulating insulating oil, and the adsorption unit is used to remove moisture and dissolved gases from the circulating insulating oil. This allows for the step-by-step and targeted removal of particulate impurities, moisture, and dissolved gases, resulting in a highly efficient and complete purification process that significantly improves the overall dielectric properties of the insulating oil.

[0009] Furthermore, the adsorption unit includes a housing and a multi-layer composite filter assembly disposed within the housing. The multi-layer composite filter assembly includes a pre-filter, a middle filter element, and a post-filter element arranged sequentially along the direction of insulating oil flow.

[0010] Furthermore, the pre-filter is made of stainless steel sintered mesh, which is used to intercept larger diameter particles and play a primary protection role.

[0011] The central filter element uses a high-precision glass fiber or polymer material filter element, which is responsible for intercepting micron-sized fine particles, including metal wear debris, fibers and other contaminants.

[0012] The post-filter uses a homogeneous membrane filter to further ensure the uniformity of the particle size of the filtered oil. All filter materials are compatible with insulating oil for a long time and will not swell, decompose, or introduce new contaminants.

[0013] Furthermore, the adsorption unit includes molecular sieve material and activated alumina, which fully utilizes the strong adsorption capacity of molecular sieve for moisture and the synergistic adsorption effect of activated alumina for moisture and acidic substances, making the dehydration and degassing effect more thorough and reliable.

[0014] In a preferred embodiment of the present invention, the circulating flow unit includes a circulating pump and a circulating flow pipeline assembly. The circulating flow pipeline assembly includes an oil outlet circulating pipeline, an intermediate flow pipeline, and an oil inlet circulating pipeline. One end of the oil outlet circulating pipeline is connected to the outlet of the cable terminal, and the other end of the oil outlet circulating pipeline is connected to the inlet of the circulating pump. The intermediate flow pipeline includes a first intermediate flow pipeline, a second intermediate flow pipeline, and a third intermediate flow pipeline. One end of the first intermediate flow pipeline, the second intermediate flow pipeline, and the third intermediate flow pipeline are respectively connected to the outlet of the circulating pump, and the other ends of the first intermediate flow pipeline, the second intermediate flow pipeline, and the third intermediate flow pipeline are respectively connected to one end of the oil inlet circulating pipeline. The microfiltration unit and the adsorption unit are connected in series on the second intermediate flow pipeline, and the oil quality monitoring module of the intelligent monitoring unit is located on the third intermediate flow pipeline. The other end of the oil inlet circulating pipeline is connected to the inlet of the cable terminal. An oil outlet solenoid valve is installed on the oil circulation pipeline, and a first intermediate solenoid valve, a second intermediate solenoid valve, and a third intermediate solenoid valve are respectively installed on the first intermediate flow pipeline, the second intermediate flow pipeline, and the third intermediate flow pipeline. With this structure, driven by the circulation pump, the insulating oil in the cable terminal can be extracted, then passed to the microfiltration unit to filter particulate impurities, then to the adsorption unit to remove moisture and impurity gases, and finally returned to the cable terminal, completing the fully automatic online purification of the insulating oil.

[0015] Furthermore, the insulating oil replenishment unit includes an insulating oil replenishment container and an insulating oil replenishment pipeline. One end of the insulating oil replenishment pipeline is connected to the outlet of the insulating oil replenishment container, and the other end is connected to the inlet of the circulating pump. An insulating oil replenishment solenoid valve is installed on the insulating oil replenishment pipeline. With this structure, a single circulating pump and part of the circulating flow pipeline assembly can be shared, enabling online automatic replenishment of insulating oil. This is convenient and fast, eliminating the need for a dedicated replenishment pump, simplifying the system structure, reducing manufacturing costs and potential failure points, and demonstrating a high degree of integration and intelligence.

[0016] A method for online purification of insulating oil inside high-voltage cable terminals. It includes multiple working modes, namely: Normal standby mode; in this working mode, the oil level monitoring module is in operation, which detects the capacity of the insulating oil inside the cable terminal in real time, and all solenoid valves remain closed. Oil replenishment mode: When the oil level monitoring module detects that the oil level in the cable terminal is less than the set threshold, the insulating oil replenishment solenoid valve and the first intermediate solenoid valve are opened, while the other solenoid valves remain closed. The circulation pump is started to extract the insulating oil from the insulating oil replenishment container and replenish the cable terminal with new insulating oil through the insulating oil replenishment pipeline and the first intermediate flow pipeline until the oil level monitoring module detects that the oil level in the cable terminal is greater than or equal to the set threshold. Oil quality monitoring working mode: In this working mode, according to the pre-set periodic monitoring time points, the insulating oil replenishment solenoid valve and the third intermediate solenoid valve are opened, while other solenoid valves remain closed. The circulation pump is started to draw the insulating oil from the insulating oil replenishment container and flow the insulating oil into the cable terminal through the insulating oil replenishment pipeline and the third intermediate flow pipeline until the oil quantity monitoring module detects an increase in the oil quantity in the cable terminal, indicating that the insulating oil has filled the third intermediate flow pipeline. The oil quality monitoring work is then officially started. The oil outlet solenoid valve and the third intermediate solenoid valve are opened, while other solenoid valves remain closed. The circulation pump is started to draw the insulating oil from the cable terminal and transport the insulating oil to the oil quality monitoring module through the third intermediate flow pipeline, where the oil quality monitoring module performs real-time monitoring of the insulating oil. Purification Working Mode: When the oil quality monitoring module detects that the oil quality parameters of the insulating oil in the cable terminal exceed the standard, the insulating oil replenishment solenoid valve and the second intermediate solenoid valve are opened, while other solenoid valves remain closed. The circulation pump is started to extract the insulating oil from the insulating oil replenishment container and flow it into the cable terminal through the insulating oil replenishment pipeline and the second intermediate flow pipeline until the oil quantity monitoring module detects an increase in the oil quantity in the cable terminal, indicating that the insulating oil has filled the second intermediate flow pipeline. Formal purification then begins. The oil outlet solenoid valve and the second intermediate solenoid valve are opened, while other solenoid valves remain closed. The circulation pump is started to extract the insulating oil from the cable terminal and transport it through the second intermediate flow pipeline to the microfiltration unit and adsorption unit of the purification unit, where the microfiltration unit and adsorption unit perform real-time purification of the insulating oil.

[0017] In a preferred embodiment of the present invention, during the purification operation mode, the oil level monitoring module continuously monitors the volume of insulating oil inside the cable terminal. When the oil level monitoring module detects that the oil level inside the cable terminal is less than a set threshold, with the oil outlet solenoid valve and the second intermediate solenoid valve open, the insulating oil replenishment solenoid valve is also opened. Simultaneously, the circulating pump extracts insulating oil from the insulating oil replenishment container and replenishes the insulating oil into the cable terminal through the insulating oil replenishment pipeline and the second intermediate flow pipeline until the oil level monitoring module detects that the oil level inside the cable terminal is greater than or equal to the set threshold. Through the above operation, the oil volume lost during the purification process can be compensated (the adsorption and filtration of the insulating oil removes impurities and moisture, thus reducing the volume of the insulating oil), allowing for real-time replenishment and ensuring the insulation performance of the cable terminal.

[0018] Compared with the prior art, the present invention has the following advantages: 1. The purification device of the present invention can complete the purification and monitoring of insulating oil during normal operation without power outage, which significantly saves maintenance time and economic costs and improves power supply reliability.

[0019] 2. The purification device of this invention innovatively introduces an insulating oil replenishment unit, fundamentally solving the problem of oil balance during online purification. During online circulating purification, traditional solutions are prone to oil reduction and pressure drop inside the terminal due to oil extraction, pipeline obstruction, leakage, or flow resistance, forming oil-gas cavities and posing a risk of discharge. This invention, through the replenishment unit, pre-fills the pipeline at startup and dynamically replenishes clean insulating oil during operation based on real-time oil pressure (oil quantity) monitoring, ensuring that the terminal is always full and the pressure is stable, thus guaranteeing the electrical safety and normal operation of the cable terminal during the purification process.

[0020] 3. The intelligent monitoring unit tracks key parameters in the oil in real time, such as moisture, gas, and particle size. Once a deterioration trend is detected, a purification cycle is automatically initiated, shifting from reactive remediation to proactive prevention. This not only eliminates insulation hazards promptly but also slows down the aging of insulation materials, effectively extending the service life of cable terminals.

[0021] 4. This invention integrates filtration, adsorption, circulation, monitoring and compensation functions, and automatically coordinates the work of each unit through an intelligent control system, enabling unattended operation. Maintenance personnel can monitor the oil quality status, purification progress and equipment health information in real time through a remote platform, simplifying the operation and maintenance process and improving management efficiency. Attached Figure Description

[0022] Figures 1-2 These are three-dimensional structural schematic diagrams from two different perspectives of the online purification device for insulating oil inside the high-voltage cable terminal of the present invention.

[0023] Figure 3This is a simplified structural diagram of the online purification device for the internal insulating oil of the high-voltage cable terminal according to the present invention. Detailed Implementation

[0024] To enable those skilled in the art to fully understand the technical solutions of the present invention, the present invention will be further described below in conjunction with embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0025] Example 1 Combination Figures 1-3 The online purification device for insulating oil inside the high-voltage cable terminal in this embodiment includes an intelligent monitoring unit, a circulation unit, a purification unit, and an insulating oil replenishment unit. The intelligent monitoring unit includes an oil quality monitoring module 2 for real-time monitoring of the oil quality in the cable terminal 1 and an oil quantity monitoring module for monitoring the amount of insulating oil in the cable terminal 1. The circulation unit promotes the circulation of insulating oil between the cable terminal 1 and the purification unit, and the purification unit purifies the circulating insulating oil. The insulating oil replenishment unit replenishes the insulating oil into the pipeline of the circulation unit when the purification device is first started. When the intelligent monitoring unit detects that the amount of oil in the cable terminal 1 is less than a set threshold, the insulating oil in the insulating oil replenishment unit is transported to the cable terminal 1 through the circulation unit until the intelligent monitoring unit detects that the amount of oil in the cable terminal 1 is greater than or equal to the set threshold.

[0026] Combination Figures 1-3 The oil quality monitoring module 2 is located on the outside of the cable terminal 1 and includes a humidity sensor, a particle sensor, and a gas detection module. The oil quantity monitoring module includes a pressure sensor, which is located at the top of the inner cavity of the cable terminal 1 and is used to detect the pressure inside the cable terminal 1 to reflect the oil quantity of the insulating oil. Through the above structure, synchronous and real-time online monitoring of key quality parameters of the insulating oil (moisture, particles, fault gases) and the oil quantity status inside the terminal (indirectly and accurately reflected by pressure) is realized. This not only provides accurate criteria for the intelligent start and stop of the purification process, but more importantly, it can directly and sensitively sense the pressure fluctuations inside the terminal caused by changes in oil quantity, providing a core feedback signal for subsequent automatic oil replenishment control, fundamentally ensuring the safety of terminal operation.

[0027] Combination Figures 1-3 The purification unit includes a microfiltration unit 3 and an adsorption unit 4. The microfiltration unit 3 is used to remove particulate impurities from the circulating insulating oil, and the adsorption unit 4 is used to remove moisture and dissolved gases from the circulating insulating oil. This allows for the step-by-step and targeted removal of particulate impurities, moisture, and dissolved gases, resulting in a highly efficient and complete purification process that significantly improves the overall dielectric properties of the insulating oil.

[0028] Furthermore, the adsorption unit 4 includes a housing and a multi-layer composite filter assembly disposed within the housing. The multi-layer composite filter assembly includes a pre-filter, a middle filter element, and a post-filter element arranged sequentially along the direction of insulating oil flow.

[0029] Furthermore, the pre-filter is made of stainless steel sintered mesh, which is used to intercept larger diameter particles and play a primary protection role.

[0030] The central filter element uses a high-precision glass fiber or polymer material filter element, which is responsible for intercepting micron-sized fine particles, including metal wear debris, fibers and other contaminants.

[0031] The post-filter uses a homogeneous membrane filter to further ensure the uniformity of the particle size of the filtered oil. All filter materials are compatible with insulating oil for a long time and will not swell, decompose, or introduce new contaminants.

[0032] Furthermore, the adsorption unit 4 includes molecular sieve material and activated alumina, which fully utilizes the strong adsorption capacity of molecular sieve for moisture and the synergistic adsorption effect of activated alumina for moisture and acidic substances, making the dehydration and degassing effect more thorough and reliable.

[0033] Combination Figures 1-3 The circulating flow unit includes a circulating pump 5 and a circulating flow pipeline assembly. The circulating flow pipeline assembly includes an oil outlet circulating pipeline 6, an intermediate flow pipeline, and an oil inlet circulating pipeline 7. One end of the oil outlet circulating pipeline 6 is connected to the outlet of the cable terminal 1, and the other end of the oil outlet circulating pipeline 6 is connected to the inlet of the circulating pump 5. The intermediate flow pipeline includes a first intermediate flow pipeline 8, a second intermediate flow pipeline 9, and a third intermediate flow pipeline 10. One end of the first intermediate flow pipeline 8, the second intermediate flow pipeline 9, and the third intermediate flow pipeline 10 are respectively connected to the outlet of the circulating pump 5. The other ends of intermediate flow pipeline 9 and third intermediate flow pipeline 10 are respectively connected to one end of oil inlet circulation pipeline 7; the microfiltration unit 3 and adsorption unit 4 are connected in series on the second intermediate flow pipeline 9, and the oil quality monitoring module 2 of the intelligent monitoring unit is installed on the third intermediate flow pipeline 10; the other end of oil inlet circulation pipeline 7 is connected to the inlet end of cable terminal 1; an oil outlet solenoid valve 11 is provided on the oil outlet circulation pipeline 6, and a first intermediate solenoid valve 12, a second intermediate solenoid valve 13, and a third intermediate solenoid valve 14 are respectively provided on the first intermediate flow pipeline 8, the second intermediate flow pipeline 9, and the third intermediate flow pipeline 10. With the above structure, driven by the circulation pump 5, the insulating oil in cable terminal 1 can be extracted, then passed to the microfiltration unit 3 to filter particulate impurities, then passed to the adsorption unit 4 to remove moisture and impurity gases, and finally returned to cable terminal 1, completing the fully automatic online purification of insulating oil.

[0034] Combination Figures 1-3 The insulating oil replenishment unit includes an insulating oil replenishment container 15 and an insulating oil replenishment pipeline 16. One end of the insulating oil replenishment pipeline 16 is connected to the outlet of the insulating oil replenishment container 15, and the other end is connected to the inlet of the circulating pump 5. An insulating oil replenishment solenoid valve 17 is provided on the insulating oil replenishment pipeline 16. With the above structure, a single circulating pump 5 and part of the circulating flow pipeline assembly can be shared to automatically replenish the insulating oil online, which is convenient and fast. The specific operation is as follows: In the oil replenishment state, the circulating pump 5 is started to extract the insulating oil from the insulating oil replenishment container 15, and new insulating oil is replenished into the cable terminal 1 through the insulating oil replenishment pipeline 16 and the first intermediate flow pipeline 8 until the oil level monitoring module detects that the oil level in the cable terminal 1 is greater than or equal to the set threshold. Therefore, when oil replenishment is needed, the control system can close the terminal oil outlet line and directly drive the clean oil in the replenishment container to be rapidly injected into the terminal through the insulating oil replenishment line 16 and the first intermediate flow line 8. This path avoids the purification unit (microfiltration and adsorption), preventing the oil replenishment process from being affected by the resistance of the purification unit, significantly improving the oil replenishment response speed and efficiency, and quickly restoring the internal pressure of the terminal. At the same time, this design shares the circulation pump 5 and most of the pipelines, eliminating the need for an additional dedicated oil replenishment pump, simplifying the system structure, reducing manufacturing costs and potential failure points, and demonstrating a high degree of integration and intelligence.

[0035] Example 2 Combination Figures 1-3 The online purification method for the insulating oil inside the high-voltage cable terminal in this embodiment includes multiple working modes, namely: Normal standby mode; in this working mode, the oil level monitoring module is in working condition, and it detects the capacity of the insulating oil inside the cable terminal 1 in real time, while all solenoid valves remain closed.

[0036] Oil replenishment mode: When the oil level monitoring module detects that the oil level in cable terminal 1 is less than the set threshold, the insulating oil replenishment solenoid valve 17 and the first intermediate solenoid valve 12 are opened, while other solenoid valves remain closed. The circulation pump 5 is started to extract the insulating oil from the insulating oil replenishment container 15 and replenish the cable terminal 1 with new insulating oil through the insulating oil replenishment pipeline 16 and the first intermediate flow pipeline 8 until the oil level monitoring module detects that the oil level in cable terminal 1 is greater than or equal to the set threshold.

[0037] Oil quality monitoring working mode: In this working mode, according to the pre-set periodic monitoring time points, the insulating oil replenishment solenoid valve 17 and the third intermediate solenoid valve 14 are opened, while other solenoid valves remain closed. The circulation pump 5 is started to draw the insulating oil from the insulating oil replenishment container 15 and flow the insulating oil into the cable terminal 1 through the insulating oil replenishment pipeline 16 and the third intermediate flow pipeline 10 until the oil quantity monitoring module detects an increase in the oil quantity in the cable terminal 1, indicating that the insulating oil has filled the third intermediate flow pipeline 10. The oil quality monitoring work is then officially started. The oil outlet solenoid valve 11 and the third intermediate solenoid valve 14 are opened, while other solenoid valves remain closed. The circulation pump 5 is started to draw the insulating oil from the cable terminal 1 and transport the insulating oil to the oil quality monitoring module 2 through the third intermediate flow pipeline 10. The oil quality monitoring module 2 then performs real-time monitoring of the insulating oil.

[0038] Purification Working Mode: When the oil quality monitoring module 2 detects that the oil quality parameters of the insulating oil in the cable terminal 1 exceed the standard, it opens the insulating oil replenishment solenoid valve 17 and the second intermediate solenoid valve 13, while keeping other solenoid valves closed. The circulation pump 5 is started to draw out the insulating oil from the insulating oil replenishment container 15 and flow it into the cable terminal 1 through the insulating oil replenishment pipeline 16 and the second intermediate flow pipeline 9 until the oil quantity monitoring module detects an increase in the oil quantity in the cable terminal 1, indicating that the insulating oil has filled the second intermediate flow pipeline 9. Formal purification is then carried out by opening the oil outlet solenoid valve 11 and the second intermediate solenoid valve 13, while keeping other solenoid valves closed. The circulation pump 5 is started to draw out the insulating oil from the cable terminal 1 and transport it to the microfiltration unit 3 and the adsorption unit 4 of the purification unit through the second intermediate flow pipeline 9. The microfiltration unit 3 and the adsorption unit 4 then perform real-time purification of the insulating oil.

[0039] Furthermore, in the purification mode, the oil level monitoring module continuously monitors the volume of insulating oil inside the cable terminal 1. When the oil level monitoring module detects that the oil level in the cable terminal 1 is less than a set threshold, with the oil outlet solenoid valve 11 and the second intermediate solenoid valve 13 open, the insulating oil replenishment solenoid valve 17 is also opened. Simultaneously, the circulation pump 5 draws out the insulating oil from the insulating oil replenishment container 15 and replenishes the insulating oil into the cable terminal 1 through the insulating oil replenishment pipeline 16 and the second intermediate flow pipeline 9 until the oil level monitoring module detects that the oil level in the cable terminal 1 is greater than or equal to the set threshold. Through the above operations, the oil volume lost during the purification process can be compensated (the adsorption and filtration of the insulating oil removes impurities and moisture, thus reducing the capacity of the insulating oil), and real-time replenishment can be performed to ensure the insulation performance of the cable terminal 1.

[0040] The above are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above content. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. An online purification device for the insulating oil inside a high-voltage cable terminal, characterized in that, It includes an intelligent monitoring unit, a circulation unit, a purification unit, and an insulating oil replenishment unit; The intelligent monitoring unit includes an oil quality monitoring module for real-time monitoring of oil quality and an oil quantity monitoring module for monitoring the amount of insulating oil in the cable terminal. The circulating flow unit is used to promote the circulation of insulating oil between the cable terminal and the purification unit, and the purification unit is used to purify the circulating insulating oil. The insulating oil replenishment unit is used to replenish insulating oil into the pipeline of the circulation flow unit and the cable terminal. When the pipeline of the circulation flow unit is not filled with insulating oil before the purification device is started, the insulating oil in the insulating oil replenishment unit is transported to the pipeline through the circulation flow unit. When the intelligent monitoring unit detects that the amount of oil in the cable terminal is less than the set threshold, the insulating oil in the insulating oil replenishment unit is transported to the cable terminal through the circulation flow unit until the intelligent monitoring unit detects that the amount of oil in the cable terminal is greater than or equal to the set threshold.

2. The online purification device for internal insulating oil of high-voltage cable terminals according to claim 1, characterized in that, The oil quality monitoring module is located on the outside of the cable terminal and includes a humidity sensor, a particle sensor, and a gas detection module; the oil quantity monitoring module includes a pressure sensor, which is located at the top of the inner cavity of the cable terminal and is used to detect the pressure in the inner cavity of the cable terminal to reflect the amount of insulating oil.

3. The online purification device for internal insulating oil of high-voltage cable terminals according to claim 1, characterized in that, The purification unit includes a microfiltration unit and an adsorption unit. The microfiltration unit is used to remove particulate impurities from the circulating insulating oil, and the adsorption unit is used to remove moisture and dissolved gases from the circulating insulating oil.

4. The online purification device for internal insulating oil of high-voltage cable terminals according to claim 3, characterized in that, The adsorption unit includes a housing and a multi-layer composite filter assembly disposed within the housing. The multi-layer composite filter assembly includes a pre-filter, a middle filter element, and a post-filter element arranged sequentially along the direction of insulating oil flow.

5. The online purification device for internal insulating oil of high-voltage cable terminals according to claim 4, characterized in that, The pre-filter is made of stainless steel sintered mesh; the intermediate filter element is made of high-precision glass fiber or polymer material; and the post-filter element is made of homogeneous membrane.

6. The online purification device for internal insulating oil of high-voltage cable terminals according to claim 3, characterized in that, The adsorption unit includes molecular sieve material and activated alumina.

7. The online purification device for internal insulating oil of high-voltage cable terminals according to claim 3, characterized in that, The circulating flow unit includes a circulating pump and a circulating flow pipeline assembly. The circulating flow pipeline assembly includes an oil outlet circulating pipeline, an intermediate flow pipeline, and an oil inlet circulating pipeline. One end of the oil outlet circulating pipeline is connected to the outlet of the cable terminal, and the other end is connected to the inlet of the circulating pump. The intermediate flow pipeline includes a first intermediate flow pipeline, a second intermediate flow pipeline, and a third intermediate flow pipeline. One end of each of the first, second, and third intermediate flow pipelines is connected to the outlet of the circulating pump, and the other end of each is connected to one end of the oil inlet circulating pipeline. The microfiltration unit and the adsorption unit are connected in series on the second intermediate flow pipeline, and the oil quality monitoring module is located on the third intermediate flow pipeline. The other end of the oil inlet circulating pipeline is connected to the inlet of the cable terminal. An oil outlet solenoid valve is provided on the oil outlet circulation pipeline, and a first intermediate solenoid valve, a second intermediate solenoid valve, and a third intermediate solenoid valve are respectively provided on the first intermediate flow pipeline, the second intermediate flow pipeline, and the third intermediate flow pipeline.

8. The online purification device for internal insulating oil of high-voltage cable terminals according to claim 7, characterized in that, The insulating oil replenishment unit includes an insulating oil replenishment container and an insulating oil replenishment pipeline. One end of the insulating oil replenishment pipeline is connected to the outlet of the insulating oil replenishment container, and the other end of the insulating oil replenishment pipeline is connected to the inlet of the circulating pump. An insulating oil replenishment solenoid valve is provided on the insulating oil replenishment pipeline.

9. A purification method for the online purification device for insulating oil inside a high-voltage cable terminal as described in claim 8, characterized in that, It includes multiple working modes, namely: Normal standby mode; in this working mode, the oil level monitoring module is in operation, which detects the capacity of the insulating oil inside the cable terminal in real time, and all solenoid valves remain closed. Oil replenishment mode: When the oil level monitoring module detects that the oil level in the cable terminal is less than the set threshold, the insulating oil replenishment solenoid valve and the first intermediate solenoid valve are opened, while the other solenoid valves remain closed. The circulation pump is started to extract the insulating oil from the insulating oil replenishment container and replenish the cable terminal with new insulating oil through the insulating oil replenishment pipeline and the first intermediate flow pipeline until the oil level monitoring module detects that the oil level in the cable terminal is greater than or equal to the set threshold. Oil quality monitoring working mode: In this working mode, according to the pre-set periodic monitoring time points, the insulating oil replenishment solenoid valve and the third intermediate solenoid valve are opened, while other solenoid valves remain closed. The circulation pump is started to draw the insulating oil from the insulating oil replenishment container and flow the insulating oil into the cable terminal through the insulating oil replenishment pipeline and the third intermediate flow pipeline until the oil quantity monitoring module detects an increase in the oil quantity in the cable terminal, indicating that the insulating oil has filled the third intermediate flow pipeline. The oil quality monitoring work is then officially started. The oil outlet solenoid valve and the third intermediate solenoid valve are opened, while other solenoid valves remain closed. The circulation pump is started to draw the insulating oil from the cable terminal and transport the insulating oil to the oil quality monitoring module through the third intermediate flow pipeline, where the oil quality monitoring module performs real-time monitoring of the insulating oil. Purification Working Mode: When the oil quality monitoring module detects that the oil quality parameters of the insulating oil in the cable terminal exceed the standard, the insulating oil replenishment solenoid valve and the second intermediate solenoid valve are opened, while other solenoid valves remain closed. The circulation pump is started to extract the insulating oil from the insulating oil replenishment container and flow it into the cable terminal through the insulating oil replenishment pipeline and the second intermediate flow pipeline until the oil quantity monitoring module detects an increase in the oil quantity in the cable terminal, indicating that the insulating oil has filled the second intermediate flow pipeline. Purification officially begins when the oil outlet solenoid valve and the second intermediate solenoid valve are opened, while other solenoid valves remain closed. The circulation pump is started to extract the insulating oil from the cable terminal and transport it to the microfiltration unit and adsorption unit of the purification unit through the second intermediate flow pipeline. The microfiltration unit and adsorption unit then perform real-time purification of the insulating oil.

10. The purification method of the online purification device for insulating oil inside high-voltage cable terminals according to claim 9, characterized in that, In the purification mode, the oil level monitoring module detects the capacity of the insulating oil inside the cable terminal in real time. When the oil level monitoring module detects that the oil level in the cable terminal is less than the set threshold, with the oil outlet solenoid valve and the second intermediate solenoid valve open, the insulating oil replenishment solenoid valve is opened. At the same time, the circulation pump draws out the insulating oil from the insulating oil replenishment container and replenishes the insulating oil into the cable terminal through the insulating oil replenishment pipeline and the second intermediate flow pipeline until the oil level monitoring module detects that the oil level in the cable terminal is greater than or equal to the set threshold.

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