An automatic oil filling system for transformers based on improved pressure oil filling equipment

Abstract

The present invention provides a transformer automatic oiling system based on improved pressure oiling equipment, including interconnected: oil source storage module, for oil storage, oil level monitoring and oil temperature control; intelligent connection module, for designing pipelines and valves, and installing intelligent connection components; pressurized oiling module, for pressure oiling using variable frequency oil pump and pressure control valve, and for oil injection quantity control in combination with throttle valve and voltage stabilizer; filtering and degassing module, for pre-filtration, degassing and drying, and for evaluating oil quality; control center module, for designing oiling control logic based on PLC control cabinet, controlling actuator to complete oiling task, and for real-time monitoring, remote control and alarm; safety guarantee module, for oil leakage detection and pressure detection. The present invention realizes a high-efficiency, low-maintenance automatic oiling process, and can also reduce the probability of equipment failure, extend the service life of transformers, reduce operation and maintenance costs, and improve the reliability and safety of power systems.

Description

Technical Field

[0001] The invention relates to the technical field of transformer oil filling, in particular to an automatic transformer oil filling system based on improved pressure oil filling equipment. Background Art

[0002] An oil-immersed transformer is an electric transformer that uses transformer oil (insulating oil) as a cooling and insulating medium. Transformer oil can not only effectively insulate the windings and core of the transformer, but also remove the heat generated by the transformer during operation through convection or circulation, thereby ensuring the normal operation of the transformer. The oil filling methods of oil-immersed transformers mainly include the following: 1) Gravity oil filling method, using the gravity of the transformer oil to inject the oil from the oil tank at a high place through a pipeline into the transformer tank, which is suitable for small transformers or scenes with relatively simple on-site conditions. 2) Vacuum oil filling method, after the transformer tank is evacuated to a vacuum state, the transformer oil is injected into the tank through negative pressure, which is suitable for high-voltage and large-capacity transformers. 3) Pressure oil filling method, using an oil pump or pressurizing equipment to pressurize the transformer oil and inject it into the tank, which requires additional pressurizing equipment.

[0003] The existing oil filling methods have the following defects: 1) Gravity oil filling method, which has a slow oil filling speed and low efficiency, cannot effectively remove the air and moisture inside the transformer, and easily leads to residual bubbles, affecting the insulation performance. 2) Vacuum oil filling method, which is complicated to operate and requires high technical personnel. There is a problem of uneven local oil flow during the oil filling process. 3) Pressure oil filling method, which is difficult to control the pressure. If there is a pressure control deviation, it will cause damage to the transformer tank, and air may be entrained during the oil filling process, affecting the insulation performance. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide a transformer automatic refueling system based on improved pressure oil injection equipment, which realizes a high-efficiency, low-maintenance automatic refueling process, and can also reduce the probability of equipment failure and extend the service life of the transformer, thereby significantly reducing operation and maintenance costs and improving the reliability and safety of the power system.

[0005] To achieve the above object, the present invention provides the following solution: a transformer automatic oiling system based on improved pressure oiling equipment, comprising:

[0006] An oil source storage module is used to deploy an oil source storage tank and set a sensor and a heater in the oil source storage tank to perform oil level monitoring and oil temperature control;

[0007] Smart connection module, used for piping design and valve design, and installation of smart connection components at the transformer tank opening or oil filling port;

[0008] The pressurized oil injection module is used to perform pressure oil injection using a variable frequency oil pump and a pressure control valve, and to control the oil injection amount in combination with a throttle valve and a voltage stabilizer;

[0009] Filtration and degassing module, which uses multi-stage filters to remove particulate matter and impurities in transformer oil, uses degassing and drying technologies to remove dissolved moisture and microbubbles in transformer oil, and uses sensors to monitor multiple parameters in transformer oil in real time to comprehensively evaluate oil quality and adjust oil injection strategies;

[0010] The control center module is used to design the oil injection control logic based on the PLC control cabinet, control the actuator to complete the oil injection task, and monitor the pressure, temperature, flow and oil quality parameters in real time for remote control and alarm;

[0011] The safety guarantee module is used to monitor in real time whether there is oil leakage at key connection parts and pipelines. If so, the relevant pipeline valves are automatically closed, and the variable frequency oil pump is monitored in real time to see if there is overpressure or underpressure. If so, the oil injection is automatically stopped;

[0012] Wherein, the oil source storage module, the intelligent connection module, the pressurized oil injection module, the filtering and degassing module, the control center module and the safety guarantee module are interconnected.

[0013] Optionally, the oil source storage module includes:

[0014] The oil source storage unit is used to select an oil source storage tank made of corrosion-resistant stainless steel according to the transformer requirements, and to equip the oil source storage tank with a sealing cover and a drain port;

[0015] An oil level monitoring unit, used to monitor the oil level inside the oil source tank in real time using an ultrasonic sensor or a float liquid level sensor, and transmit the oil level data to the control center module in real time;

[0016] The constant temperature control unit is used to install an electric heater and a temperature sensor on the oil source storage tank, and in combination with a thermostat, to control and monitor the oil temperature of the oil source storage tank, and then transmit the oil temperature data to the control center module in real time.

[0017] Optionally, the intelligent connection module includes:

[0018] The pipeline connection unit is used to select the pipeline diameter according to the oil injection flow rate, add flexible joints to the pipeline, divide the pipeline into multiple independent branches, and install micro-oil sensors at the joints and valves of the pipeline to monitor whether there is oil leakage in real time;

[0019] A valve control unit, used to install a relief valve or a pressure relief valve in the pipeline, an automatic exhaust valve at a high point of the pipeline, and an electric shut-off valve connected to the safety assurance module at the inlet and outlet of the pipeline;

[0020] The intelligent connection unit is used to install a position sensor on each valve, monitor the valve switch status in real time, and then transmit the valve switch status data to the control center module in real time.

[0021] Optionally, the pressurized oil injection module includes:

[0022] The frequency conversion control unit is used to preset the output flow and pressure of the oil pump according to the transformer capacity and oil injection requirements, monitor the output value of the oil pump in real time through the pressure sensor and flow meter, and adjust the operating parameters of the oil pump using the frequency converter according to the changes in the output value of the oil pump;

[0023] The pressure control unit is used to select the electric proportional pressure valve, and use the installed pressure sensor to monitor the pipeline pressure value in real time, and adjust the valve opening of the electric proportional pressure valve according to the pipeline pressure value using the electrical signal.

[0024] The throttling and voltage-stabilizing unit is used to install a throttle valve between the oil pump outlet and the electric proportional pressure valve, and to install a multi-stage voltage stabilizer after the throttle valve, so as to adjust the opening of the throttle valve according to the output value of the oil pump.

[0025] Optionally, the filtration and degassing module comprises:

[0026] A pre-filter unit is used to connect a coarse filter and a fine filter in parallel to obtain a multi-stage filter, and two sets of the multi-stage filters are designed to support online switching and cleaning of the multi-stage filters, and differential pressure sensors are installed at both ends of the multi-stage filters to monitor the blockage degree of the filter element in real time;

[0027] Degassing unit for separating microbubbles in the oil using a centrifugal separator or ultrasonic technology;

[0028] A drying unit for absorbing water from the oil using replaceable adsorbent material;

[0029] The oil quality monitoring unit is used to detect the dissolved water content in the oil using a capacitive moisture sensor or an infrared moisture sensor, detect the dissolved gas content in the oil using a spectral gas sensor or a thermal conductivity gas sensor, and detect the particle concentration in the oil using a laser particle counter to obtain oil quality monitoring data;

[0030] The dynamic adjustment unit is used to transmit the oil quality monitoring data to the control center module in real time for oil quality analysis, and dynamically adjust the oil injection strategy according to the analysis results.

[0031] Optionally, the control center module includes:

[0032] PLC control cabinet configuration unit, used to select a PLC control cabinet that supports multiple input and output interfaces, and configure a DC power supply and multiple communication protocols in the selected PLC control cabinet;

[0033] The control logic unit is used to preset the oil filling process and safety protection logic, dynamically adjust the operating status of the oil pump and valve according to the sensor data, and detect whether there is abnormal data in the sensor data. If so, the oil filling is automatically stopped and an alarm is triggered, and the key parameters of the oil filling process are uploaded to the cloud platform or local database;

[0034] The data acquisition and monitoring unit is used to preset the data acquisition frequency, collect sensor data through the analog input interface of the PLC control cabinet, filter, denoise and process the collected sensor data to obtain standard sensor data, analyze the trend of the standard sensor data through the built-in algorithm, and predict possible faults based on the data trend, and then transmit the standard sensor data and the analyzed data trend to the cloud platform or SCADA system for remote monitoring and control;

[0035] The drive execution unit is used to control the speed of the oil pump motor using the frequency converter, dynamically adjust the oil injection flow and pressure, and control the switch status of all valves using the electric actuator.

[0036] Optionally, the built-in algorithm includes:

[0037] The trend analysis subunit is used to calculate the change trend of the standard sensor data by using a sliding window and linear regression. The formula for calculating the change trend is:

[0038]

[0039] Among them, Slope p and Slope Q are the changing rates of pressure and flow in the window, t i For time point, is the time point and mean value in the window, and are the mean values ​​of pressure and flow rate in the window respectively;

[0040] When the Slope p When Slope > 0, the pressure is on the rise. p When Slope is less than 0, the pressure is decreasing. Q When Slope > 0, the flow rate is on the rise. Q When <0, the flow rate is decreasing;

[0041] The anomaly detection subunit is used to identify anomalies in the standard sensor data by using threshold detection and residual analysis. The formula for identifying abnormal data is:

[0042] Residual P (t) = P norm (t)-(Slope P ·t+b P )

[0043] Residual Q (t) = Q norm (t)-(Slope Q ·t+b Q )

[0044] Among them, Residual P (t) and Residual Q (t) are the residuals between the actual and predicted data for pressure and flow, respectively, norm (t) and Q norm (t) are the normal ranges of pressure and flow, b p and b Q are the intercepts of the linear regression models;

[0045] When | Residual P (t)>3·P std or |Residual Q (t)>3·Q std When , it is judged as abnormal, where P std and Q std are the standard deviations of pressure and flow, respectively;

[0046] The fault prediction subunit is used to calculate the future pressure value and the future flow value according to the change trend of the current pressure and flow, and predict the future fault.

[0047] Optionally, the security assurance module includes:

[0048] A leakage protection unit is used to install a trace oil sensor at a location prone to leakage, collect, transmit and analyze the data of the trace oil sensor in real time, determine whether there is actually oil leakage, and if so, automatically close the valve of the corresponding pipeline;

[0049] The pressure protection unit is used to install pressure sensors and pressure relief valves at the oil pump outlet, the middle section of the pipeline and the transformer interface, and set the upper and lower pressure limits of different installation locations, and judge whether each pressure sensor is greater than the corresponding upper pressure limit. If so, the oil pump is closed and the pressure relief valve is opened, and it is judged whether each pressure sensor is less than the lower pressure limit. If so, the oil injection operation is suspended and a fault check is performed;

[0050] The emergency protection unit is used to install manual valves at the oil pump outlet, the middle section of the pipeline and the transformer interface. An operation guide sign is set next to each manual valve to indicate the valve's switching direction and operating steps. An uninterruptible power supply is configured in the PLC control cabinet to provide short-term power supply in the event of a power outage.

[0051] The present invention discloses the following technical effects by providing a transformer automatic oiling system based on an improved pressure oiling device:

[0052] 1. High efficiency of oil filling: 1) By setting up an oil source storage tank with oil level monitoring, constant temperature control and oil quality monitoring functions, the oil quality and storage safety can be ensured; 2) By designing a high-precision oil pump, it can provide stable oil flow and pressure to meet the oil filling needs of different transformers, and use the frequency converter to automatically adjust the output pressure and flow according to actual needs; 3) By designing an electric proportional pressure valve, it is conducive to the electric signal to control the valve opening, and can accurately maintain the set pressure range to prevent excessive pressure from causing impact on the transformer oil tank. Improve oil filling efficiency, extend equipment life, and reduce maintenance costs.

[0053] 2. Improve the purity and insulation performance of oil: By combining high-efficiency filtration, intelligent degassing, drying technology and real-time oil quality monitoring, it can effectively remove particulate matter, impurities, dissolved water and gas, ensure the cleanliness of oil, and improve insulation performance and operational reliability.

[0054] 3. Reliable oil circuit connection: 1) By designing multiple independent pipelines, it is easy to install, maintain and replace; 2) By setting overflow valves or pressure relief valves, automatic exhaust valves, electric shut-off valves, etc., an intelligent valve system is formed, which can monitor the pipeline status in real time and alarm in time when abnormalities are found.

[0055] 4. High degree of intelligence: 1) By configuring the PLC control cabinet, it can intelligently control the actuator to complete the oil filling task, monitor key parameters such as pressure, temperature, flow, oil quality in real time, and ensure the safety and efficiency of the oil filling process. 2) By setting the built-in algorithm, it can not only analyze data trends (such as pressure change curves, flow fluctuations), but also predict future pressure values, flow values ​​and possible faults.

[0056] 5. High safety: 1) By using sensors for leakage detection, it is possible to monitor oil leakage in real time and take corresponding protective measures to prevent oil waste and environmental pollution; 2) By using sensors for pressure detection, it is possible to prevent excessive or low pressure from damaging equipment and transformers and reduce the occurrence of failures; 3) By installing manual valves, in the event of an unexpected power outage or control system failure, the valves can be manually closed and the oil circuit can be blocked to ensure the safety of equipment and transformers; 4) By configuring an uninterruptible power supply, a short-term power supply can be provided to the PLC and key actuators (such as electric valves) in the event of a power outage, ensuring the completion of key operations and providing response time for emergencies.

[0057] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0059] Figure 1 A schematic diagram of a system architecture provided by an embodiment of the present invention;

[0060] Figure 2 A schematic diagram of a process of pressurized oil injection provided by an embodiment of the present invention;

[0061] Figure 3 A schematic diagram of the flow of oil injection control provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0062] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0063] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0064] like Figure 1 As shown, the present invention provides a transformer automatic oiling system based on improved pressure oiling equipment, including an oil source storage module, an intelligent connection module, a pressurized oiling module, a filtering and degassing module, a control center module and a safety assurance module that are interconnected.

[0065] 1. Oil source storage module

[0066] It is used to deploy oil source storage tanks and set sensors and heaters in the oil source storage tanks to monitor oil level and control oil temperature. The oil source storage module includes:

[0067] 1.1 Oil source storage unit

[0068] According to the needs of the transformer, an oil source storage tank made of corrosion-resistant stainless steel (such as 304 or 316 stainless steel, with a polished inner wall to prevent oil contamination) is selected, and the oil source storage tank is equipped with a sealing cover (to prevent the entry of external air, moisture or impurities to ensure the purity of the oil) and a drain port (designed at the bottom for regular cleaning of sediments).

[0069] 1.2 Oil level monitoring unit

[0070] It is used to use an ultrasonic sensor or a float liquid level sensor to monitor the oil level inside the oil source storage tank in real time, and transmit the oil level height data to the control center module in real time.

[0071] 1.3 Constant temperature control unit

[0072] It is used to install an electric heater (such as a PTC heater) and a temperature sensor on the oil source storage tank (bottom or side wall), and in combination with a thermostat, to control and monitor the oil temperature of the oil source storage tank, and then transmit the oil temperature data to the control center module in real time.

[0073] 2. Intelligent connection module

[0074] Used for piping design and valve design, and installation of smart connection components at transformer tank openings or oil filling ports. Smart connection modules include:

[0075] 2.1 Pipeline connection unit

[0076] The pipe material is oil-resistant and high-temperature resistant, such as stainless steel (304 or 316L) or high-strength composite materials (such as polytetrafluoroethylene PTFE lined pipe). The seal material is high-temperature resistant and corrosion-resistant rubber seals (such as fluororubber or silicone rubber) to ensure long-term use without leakage.

[0077] Select the appropriate pipeline diameter (such as DN25, DN50, etc.) according to the oil injection flow, add flexible joints to the pipeline (such as bellows or hoses to absorb vibration and thermal expansion and prevent pipeline damage), divide the pipeline into multiple independent branches (multiple independent sections for easy installation, maintenance and replacement), and install trace oil sensors at the joints and valves of the pipeline to monitor in real time whether there is oil leakage.

[0078] 2.2 Valve control unit

[0079] Main valve: Electric ball valve or electric butterfly valve is selected, which has the function of fast opening and closing and is suitable for high-pressure and large-flow oil control.

[0080] Safety valve: Install an overflow valve or pressure relief valve in the pipeline. When the system pressure exceeds the set value, it automatically releases excess pressure to protect the safety of the equipment.

[0081] Exhaust valve: Install an automatic exhaust valve at the high point of the pipeline to remove residual air in the pipeline and prevent bubbles from affecting the oil injection effect.

[0082] Electric shut-off valve: Electric shut-off valves connected to the safety assurance module are installed at the pipeline inlet and outlet; when leakage or other abnormal conditions are detected, the system automatically closes the shut-off valve to prevent the flow of oil.

[0083] 2.3 Intelligent connection unit

[0084] It is used to install a position sensor on each valve to monitor the valve switch status in real time, and then transmit the valve switch status data to the control center module in real time (control the opening and closing of the valve through PLC, and automatically switch the oil circuit according to the oil filling process).

[0085] 3. Pressurized oil injection module

[0086] like Figure 2 As shown, a variable frequency oil pump and a pressure control valve are used for pressure oil injection, and a throttle valve and a voltage regulator are used to control the oil injection amount. The pressure oil injection module includes:

[0087] 3.1 Frequency conversion control unit

[0088] Oil pump selection: Choose a gear pump or a screw pump, which has the characteristics of high efficiency, low noise and stable output. The pump body is made of oil-resistant materials (such as cast iron or stainless steel), and the seal is made of high temperature and corrosion resistant rubber material.

[0089] Inverter selection: Choose a high-precision inverter to support real-time adjustment of motor speed and control the output flow and pressure of the oil pump.

[0090] According to the transformer capacity and oil injection requirements, the output flow and pressure of the oil pump are preset, and the output value of the oil pump is monitored in real time through the pressure sensor and flow meter. According to the changes in the output value of the oil pump, the frequency converter is used to adjust the operating parameters of the oil pump;

[0091] 3.2 Pressure control unit

[0092] Pressure valve selection: Choose an electric proportional pressure valve to control the valve opening through electrical signals and accurately adjust the pressure. The valve body is made of stainless steel or aluminum alloy, and the seal is made of high temperature and corrosion resistant materials.

[0093] It is used to select an electric proportional pressure valve, and use the installed pressure sensor to monitor the pipeline pressure value in real time, and adjust the valve opening of the electric proportional pressure valve according to the pipeline pressure value using an electrical signal.

[0094] 3.3 Throttling and voltage stabilization unit

[0095] It is used to install a throttle valve between the oil pump outlet and the electric proportional pressure valve (for initial pressure stabilization), and to install a multi-stage pressure stabilizer after the throttle valve (to absorb pressure fluctuations and smooth output pressure), and to adjust the opening of the throttle valve according to the output value of the oil pump.

[0096] 4. Filtration and degassing module

[0097] It is used to remove particulate matter and impurities in transformer oil using multi-stage filters, remove dissolved moisture and microbubbles in transformer oil using degassing and drying technologies, and use sensors to monitor multiple parameters in transformer oil in real time to comprehensively evaluate oil quality and adjust oil injection strategies. The filtration and degassing module includes:

[0098] 4.1 Pre-filtration unit

[0099] Coarse filter: A stainless steel mesh filter with a filtration accuracy of 50 to 100 μm is used to remove large particles of impurities.

[0100] Fine filter: Use high-precision filter element (such as glass fiber filter element or polyester filter element) with a filtration accuracy of 1 to 5 μm to remove fine particles.

[0101] Filter element material: high temperature resistant and corrosion resistant materials are selected to ensure that long-term use does not affect the filtering effect.

[0102] A coarse filter and a fine filter are connected in parallel to obtain a multi-stage filter. Two groups of the multi-stage filters are designed to support online switching and cleaning of the multi-stage filters. Pressure difference sensors are installed at both ends of the multi-stage filters to monitor the blockage degree of the filter element in real time.

[0103] 4.2 Degassing unit

[0104] It is used to separate microbubbles in oil using a centrifugal separator or ultrasonic technology. The centrifugal separator generates centrifugal force through high-speed rotation to separate the bubbles from the oil; the ultrasonic technology uses ultrasonic vibration to destroy the bubble structure and make the bubbles escape.

[0105] 4.3 Drying unit

[0106] Used to absorb water from oil using replaceable adsorbent materials (such as molecular sieves or silica gel).

[0107] 4.4 Oil quality monitoring unit

[0108] It is used to detect the dissolved moisture content in oil (with an accuracy of up to 1ppm) using a capacitive moisture sensor or an infrared moisture sensor, detect the dissolved gas content (such as oxygen and nitrogen) in oil using a spectral gas sensor or a thermal conductivity gas sensor, and detect the particle concentration in oil using a laser particle counter to obtain oil quality monitoring data.

[0109] 4.5 Dynamic Adjustment Unit

[0110] It is used to transmit the oil quality monitoring data to the control center module in real time for oil quality analysis, and dynamically adjust the oil injection strategy according to the analysis results. For example, when the moisture or gas content exceeds the standard, the system automatically extends the degassing and drying time, or increases the vacuum pump power. When the particle concentration exceeds the standard, the system automatically switches to the spare filter or prompts to replace the filter element.

[0111] 5. Control center module

[0112] like Figure 3 As shown, based on the PLC control cabinet, the oil injection control logic is designed to control the actuator to complete the oil injection task, and monitor the pressure, temperature, flow and oil quality parameters in real time for remote control and alarm.

[0113] The control center modules include:

[0114] 5.1PLC control cabinet configuration unit

[0115] It is used to select PLC control cabinets that support multiple input and output interfaces, are equipped with high-speed processors, support complex logic operations and real-time data processing, and configure stable DC power supplies and multiple communication protocols such as Modbus, Profibus, Ethernet / IP in the selected PLC control cabinet to achieve communication with sensors, actuators and remote systems.

[0116] 5.2 Control Logic Unit

[0117] It is used to preset the oil injection process and safety protection logic, dynamically adjust the operating status of the oil pump and valve according to the sensor data (such as pressure, flow, temperature), and detect whether there is abnormal data in the sensor data (such as excessive pressure, low oil temperature, leakage). If so, it will automatically stop the oil injection and trigger the alarm, and then upload the key parameters of the oil injection process (such as pressure, flow, oil quality) to the cloud platform or local database.

[0118] Human Machine Interface (HMI): Equipped with a touch screen to display the oil injection process, real-time parameters and alarm information. Provide a parameter setting interface to facilitate operators to adjust parameters such as oil injection pressure and flow.

[0119] 5.3 Data Acquisition and Monitoring Unit

[0120] It is used to preset the data collection frequency (such as 10 times per second to ensure real-time performance), collect sensor data through the analog input interface of the PLC control cabinet, filter, denoise and process the collected sensor data to obtain standard sensor data, analyze the trend of the standard sensor data through the built-in algorithm, and predict possible faults based on the data trend, and then transmit the standard sensor data and the analyzed data trend to the cloud platform or SCADA system for remote monitoring and control.

[0121] 5.31 Various types of sensors include:

[0122] Pressure sensor: Use a high-precision pressure sensor (such as a piezoresistive or capacitive sensor), and select the range according to the system pressure range (such as 0-10MPa). Install pressure sensors at key locations in the pipeline (such as the oil pump outlet, before and after the valve) and in the transformer tank to monitor pressure changes in real time.

[0123] Temperature sensor: Use a high-precision temperature sensor (such as a thermal resistor or a thermocouple) with a range of -40°C to 150°C. Install temperature sensors at the oil pump outlet and oil tank to monitor the oil temperature.

[0124] Flow meter: Use a high-precision flow meter (such as a turbine flow meter or an electromagnetic flow meter), and select the range according to the oil injection flow rate (such as 0-100L / min). Install a flow meter at the oil pump outlet to monitor the oil injection flow rate and cumulative oil injection volume in real time.

[0125] 5.32 The built-in algorithms described include:

[0126] 1) Trend analysis subunit

[0127] It is used to calculate the change trend of the standard sensor data by using a sliding window and linear regression. The formula for calculating the change trend is:

[0128]

[0129] Among them, Slope p and Slope Q are the changing rates of pressure and flow in the window, t i For time point, is the time point and mean value in the window, and are the mean values ​​of pressure and flow rate in the window, respectively.

[0130] When the Slope p When Slope > 0, the pressure is on the rise. p When Slope is less than 0, the pressure is decreasing. Q When Slope > 0, the flow rate is on the rise. QWhen <0, the flow rate is decreasing.

[0131] 2) Anomaly Detection Subunit

[0132] The formula for identifying abnormalities in the standard sensor data by using threshold detection and residual analysis is:

[0133] Residual P (t) = P norm (t)-(Slope P ·t+b P )

[0134] Residual Q (t) = Q norm (t)-(Slope Q ·t+b Q )

[0135] Among them, Residual P (t) and Residual Q (t) are the residuals between the actual and predicted data for pressure and flow, respectively, norm (t) and Q norm (t) are the normal ranges of pressure and flow, b p and b Q are the intercepts of the linear regression models.

[0136] When | Residual P (t)|>3·P std or |Residual Q (t)|>3·Q std When , it is judged as abnormal, where P std and Q std are the standard deviations of pressure and flow, respectively.

[0137] 3) Fault prediction subunit

[0138] It is used to calculate the future pressure value and future flow value according to the changing trend of current pressure and flow, and predict future faults.

[0139] 5.4 Driver Execution Unit

[0140] The frequency converter is used to control the rotation speed of the oil pump motor, dynamically adjust the oil injection flow and pressure, and use the electric actuator to control the switching status of all valves.

[0141] 6. Security Assurance Module

[0142] It is used to monitor whether there is oil leakage in key connection parts and pipelines in real time. If so, it will automatically close the relevant pipeline valves, and monitor whether the variable frequency oil pump has overpressure and underpressure in real time. If so, it will automatically stop oil injection. The safety guarantee module includes:

[0143] 6.1 Leakage protection unit

[0144] It is used to install trace oil sensors (such as capacitive or optical sensors) at locations prone to leakage (pipeline joints, valves, oil pump outlets, transformer interfaces, etc.), collect, transmit and analyze data from the trace oil sensors in real time, and determine whether there is actually an oil leakage. If so, the valves of the corresponding pipelines are automatically closed.

[0145] 6.2 Pressure protection unit

[0146] It is used to install pressure sensors and pressure relief valves at the oil pump outlet, the middle section of the pipeline and the transformer interface respectively, and set the upper and lower pressure limits of different installation locations, to judge whether each pressure sensor is greater than the corresponding upper pressure limit. If so, the oil pump is closed and the pressure relief valve is opened, and it is judged whether each pressure sensor is less than the lower pressure limit. If so, the oil injection operation is suspended and a fault check is performed.

[0147] 6.3 Emergency protection unit

[0148] It is used to install manual valves (manual ball valves or manual butterfly valves with quick opening and closing functions) at the oil pump outlet, the middle section of the pipeline and the transformer interface. An operation guide sign is set next to each manual valve to indicate the valve's opening and closing direction and operating steps. An uninterruptible power supply (UPS) is configured in the PLC control cabinet to provide short-term power supply in the event of a power outage. The UPS power capacity is selected based on the system power consumption to ensure at least 10 minutes of emergency power supply time.

[0149] Therefore, the present invention provides a transformer automatic refueling system based on improved pressure oil injection equipment, thereby realizing a high-efficiency, low-maintenance automatic refueling process, and can also reduce the probability of equipment failure and extend the service life of the transformer, thereby significantly reducing operation and maintenance costs and improving the reliability and safety of the power system.

[0150] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0151] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A transformer automatic oiling system based on improved pressure oiling equipment, characterized in that: include: An oil source storage module is used to deploy an oil source storage tank and set a sensor and a heater in the oil source storage tank to perform oil level monitoring and oil temperature control; Smart connection module, used for piping design and valve design, and installation of smart connection components at the transformer tank opening or oil filling port; The pressurized oil injection module is used to perform pressure oil injection using a variable frequency oil pump and a pressure control valve, and to control the oil injection amount in combination with a throttle valve and a voltage stabilizer; Filtration and degassing module, which uses multi-stage filters to remove particulate matter and impurities in transformer oil, uses degassing and drying technologies to remove dissolved moisture and microbubbles in transformer oil, and uses sensors to monitor multiple parameters in transformer oil in real time to comprehensively evaluate oil quality and adjust oil injection strategies; The control center module is used to design the oil injection control logic based on the PLC control cabinet, control the actuator to complete the oil injection task, and monitor the pressure, temperature, flow and oil quality parameters in real time for remote control and alarm; The safety guarantee module is used to monitor in real time whether there is oil leakage at key connection parts and pipelines. If so, the relevant pipeline valves are automatically closed, and the variable frequency oil pump is monitored in real time to see if there is overpressure or underpressure. If so, the oil injection is automatically stopped; Wherein, the oil source storage module, the intelligent connection module, the pressurized oil injection module, the filtering and degassing module, the control center module and the safety guarantee module are interconnected.

2. According to claim 1, a transformer automatic oiling system based on improved pressure oiling equipment is characterized in that: The oil source storage module comprises: The oil source storage unit is used to select an oil source storage tank made of corrosion-resistant stainless steel according to the transformer requirements, and to equip the oil source storage tank with a sealing cover and a drain port; An oil level monitoring unit, used to monitor the oil level inside the oil source tank in real time using an ultrasonic sensor or a float liquid level sensor, and transmit the oil level data to the control center module in real time; The constant temperature control unit is used to install an electric heater and a temperature sensor on the oil source storage tank, and in combination with a thermostat, to control and monitor the oil temperature of the oil source storage tank, and then transmit the oil temperature data to the control center module in real time.

3. The transformer automatic oiling system based on the improved pressure oiling equipment according to claim 2 is characterized in that: The intelligent connection module comprises: The pipeline connection unit is used to select the pipeline diameter according to the oil injection flow rate, add flexible joints to the pipeline, divide the pipeline into multiple independent branches, and install micro-oil sensors at the joints and valves of the pipeline to monitor whether there is oil leakage in real time; A valve control unit, used to install a relief valve or a pressure relief valve in the pipeline, an automatic exhaust valve at a high point of the pipeline, and an electric shut-off valve connected to the safety assurance module at the inlet and outlet of the pipeline; The intelligent connection unit is used to install a position sensor on each valve, monitor the valve switch status in real time, and then transmit the valve switch status data to the control center module in real time.

4. The transformer automatic oiling system based on improved pressure oiling equipment according to claim 3 is characterized in that: The pressurized oil injection module comprises: The frequency conversion control unit is used to preset the output flow and pressure of the oil pump according to the transformer capacity and oil injection requirements, monitor the output value of the oil pump in real time through the pressure sensor and flow meter, and adjust the operating parameters of the oil pump using the frequency converter according to the changes in the output value of the oil pump; The pressure control unit is used to select the electric proportional pressure valve, and use the installed pressure sensor to monitor the pipeline pressure value in real time, and adjust the valve opening of the electric proportional pressure valve according to the pipeline pressure value using the electrical signal. The throttling and voltage-stabilizing unit is used to install a throttle valve between the oil pump outlet and the electric proportional pressure valve, and to install a multi-stage voltage stabilizer after the throttle valve, so as to adjust the opening of the throttle valve according to the output value of the oil pump.

5. The transformer automatic oiling system based on improved pressure oiling equipment according to claim 4 is characterized in that: The filtration and degassing module comprises: A pre-filter unit is used to connect a coarse filter and a fine filter in parallel to obtain a multi-stage filter, and two sets of the multi-stage filters are designed to support online switching and cleaning of the multi-stage filters, and differential pressure sensors are installed at both ends of the multi-stage filters to monitor the blockage degree of the filter element in real time; Degassing unit for separating microbubbles in the oil using a centrifugal separator or ultrasonic technology; A drying unit for absorbing water from the oil using replaceable adsorbent material; The oil quality monitoring unit is used to detect the dissolved water content in the oil using a capacitive moisture sensor or an infrared moisture sensor, detect the dissolved gas content in the oil using a spectral gas sensor or a thermal conductivity gas sensor, and detect the particle concentration in the oil using a laser particle counter to obtain oil quality monitoring data; The dynamic adjustment unit is used to transmit the oil quality monitoring data to the control center module in real time for oil quality analysis, and dynamically adjust the oil injection strategy according to the analysis results.

6. The transformer automatic oiling system based on improved pressure oiling equipment according to claim 5 is characterized in that: The control center module includes: PLC control cabinet configuration unit, used to select a PLC control cabinet that supports multiple input and output interfaces, and configure a DC power supply and multiple communication protocols in the selected PLC control cabinet; The control logic unit is used to preset the oil filling process and safety protection logic, dynamically adjust the operating status of the oil pump and valve according to the sensor data, and detect whether there is abnormal data in the sensor data. If so, the oil filling is automatically stopped and an alarm is triggered, and the key parameters of the oil filling process are uploaded to the cloud platform or local database; The data acquisition and monitoring unit is used to preset the data acquisition frequency, collect sensor data through the analog input interface of the PLC control cabinet, filter, denoise and process the collected sensor data to obtain standard sensor data, analyze the trend of the standard sensor data through the built-in algorithm, and predict possible faults based on the data trend, and then transmit the standard sensor data and the analyzed data trend to the cloud platform or SCADA system for remote monitoring and control; The drive execution unit is used to control the speed of the oil pump motor using the frequency converter, dynamically adjust the oil injection flow and pressure, and control the switch status of all valves using the electric actuator.

7. The transformer automatic oiling system based on improved pressure oiling equipment according to claim 6 is characterized in that: The built-in algorithms include: The trend analysis subunit is used to calculate the change trend of the standard sensor data by using a sliding window and linear regression. The formula for calculating the change trend is: Among them, Slope p and Slope Q are the changing rates of pressure and flow in the window, t i is the time point, t is the time point and mean value in the window, and are the mean values ​​of pressure and flow rate in the window respectively; When the Slope p When Slope > 0, the pressure is on the rise. p When Slope is less than 0, the pressure is decreasing. Q When Slope > 0, the flow rate is on the rise. Q When <0, the flow rate is decreasing; The anomaly detection subunit is used to identify anomalies in the standard sensor data by using threshold detection and residual analysis. The formula for identifying abnormal data is: Residual P (t)=P norm (t)-(Slope P ·t+b P ) Residual Q (t)=Q norm (t)-(Slope Q ·t+b Q ) Among them, Residual P (t) and Residual Q (t) are the residuals between the actual and predicted data for pressure and flow, respectively, norm (t) and Q norm (t) are the normal ranges of pressure and flow, b p and b Q are the intercepts of the linear regression models; when | Residual P (t)>3·P std or | Residual Q (t)>3·Q std When , it is judged as abnormal, where P std and Q std are the standard deviations of pressure and flow, respectively; The fault prediction subunit is used to calculate the future pressure value and the future flow value according to the change trend of the current pressure and flow, and predict the future fault.

8. The transformer automatic oiling system based on improved pressure oiling equipment according to claim 7 is characterized in that: The security module comprises: A leakage protection unit is used to install a trace oil sensor at a location prone to leakage, collect, transmit and analyze the data of the trace oil sensor in real time, determine whether there is actually oil leakage, and if so, automatically close the valve of the corresponding pipeline; The pressure protection unit is used to install pressure sensors and pressure relief valves at the oil pump outlet, the middle section of the pipeline and the transformer interface, and set the upper and lower pressure limits of different installation locations, and judge whether each pressure sensor is greater than the corresponding upper pressure limit. If so, the oil pump is closed and the pressure relief valve is opened, and it is judged whether each pressure sensor is less than the lower pressure limit. If so, the oil injection operation is suspended and a fault check is performed; The emergency protection unit is used to install manual valves at the oil pump outlet, the middle section of the pipeline and the transformer interface. An operation guide sign is set next to each manual valve to indicate the valve's switching direction and operating steps. An uninterruptible power supply is configured in the PLC control cabinet to provide short-term power supply in the event of a power outage.

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