Fluorescent fiber temperature measuring device for transformer winding

Abstract

This invention discloses a fluorescent fiber optic temperature measurement device for transformer windings, comprising a fiber optic temperature sensor, a control and interaction unit, a transmission and conversion unit, a flange fixing unit, and a protection unit. Through a complete system design integrating the fiber optic temperature sensor, control and interaction unit, transmission and conversion unit, flange fixing unit, and protection unit, this invention achieves a closed-loop process from temperature sensing and signal transmission to data processing and alarm control. The fiber optic temperature sensor directly contacts the winding hotspot and measures temperature based on the fluorescence decay time principle, solving the problems of large errors in traditional indirect calculation methods and poor anti-interference capabilities of electrical sensors. The system is integrated, resulting in more accurate monitoring. The fiber optic temperature sensor uses a polyimide fiber core and a polytetrafluoroethylene sheath, with no metal components, withstands high voltage, and is completely immune to EMI / RFI. The signal isolation unit of the control and interaction unit further blocks external interference, ensuring stable operation in strong electromagnetic environments.

Description

Technical Field

[0001] This invention relates to the field of temperature monitoring technology for power equipment, and more specifically, to a fluorescent fiber optic temperature measuring device for transformer windings. Background Technology

[0002] In power systems, transformers, as core equipment for energy conversion and transmission, have winding hot spot temperatures that are critical parameters affecting insulation life and operational safety. The aging rate of insulating paper is exponentially related to winding hot spot temperature; for every 6-8°C increase in temperature, the insulation life is halved. Therefore, accurate monitoring of winding hot spot temperature is essential for transformer life assessment, overload protection, and fault early warning.

[0003] The existing technology for monitoring transformer winding temperature has the following main drawbacks:

[0004] I. Limitations of traditional electrical temperature measurement methods: When using electrical sensors such as thermocouples and resistance temperature detectors (RTDs), they are easily affected by strong electromagnetic interference (EMI / RFI) inside the transformer, and the metal materials pose a risk of high-voltage breakdown, making it impossible to directly contact the winding hotspots.

[0005] II. Shortcomings of the indirect calculation method: Estimating the winding temperature by combining the top oil temperature with the load factor cannot reflect the actual hot spot temperature and is difficult to meet the requirements of high-precision monitoring.

[0006] III. Deficiencies of Existing Fiber Optic Temperature Measurement Technology: Some fluorescent fiber optic temperature measurement devices (such as the fluorescent fiber optic temperature probe and device for oil-immersed transformer windings disclosed in announcement number CN214096419U) only focus on optimizing the local structure of the probe and lack a complete system design.

[0007] 1. It lacks an integrated independent control and interaction unit, relying on external devices to process data, resulting in insufficient response speed;

[0008] 2. The sealing structure is simple, but leakage is likely to occur in a long-term oil immersion environment, resulting in significant light loss;

[0009] 3. The protective design is inadequate, the equipment is susceptible to environmental corrosion (such as rainwater and dust), and the maintenance is inconvenient;

[0010] 4. The sensors require regular calibration, which increases maintenance costs, and their multi-channel expansion capability is weak, making it difficult to adapt to transformers of different capacities.

[0011] Therefore, there is an urgent need for an integrated, highly reliable, anti-interference, and easy-to-maintain fluorescent fiber optic temperature measurement device for transformer windings to solve the above-mentioned problems of existing technologies. Summary of the Invention

[0012] The technical objective of this invention is to address the above-mentioned shortcomings by providing a fluorescent fiber optic temperature measurement device for transformer windings, thereby resolving the problems mentioned above.

[0013] To achieve the above objectives, the present invention provides the following technical solution:

[0014] A transformer winding fluorescent fiber optic temperature measuring device includes:

[0015] The fiber optic temperature sensor directly contacts the hot spot of the transformer winding, receives the excitation light and returns a temperature-related fluorescence signal, thus realizing temperature sensing without metal intervention.

[0016] The control and interaction unit centrally controls the temperature measurement process of each channel, displays temperature data in real time, and triggers over-temperature alarms.

[0017] The transmission and switching unit is used to realize the sealed switching of optical fibers inside and outside the transformer tank and to extend the signal transmission distance. It includes a through-type assembly and an external optical fiber extension line. The through-type assembly is connected between the external optical fiber extension line and the optical fiber temperature sensor. The external optical fiber extension line is connected between the control and interaction unit and the through-type assembly. The optical fiber temperature sensor is installed in the transformer tank wall through the through-type assembly.

[0018] A flange fixing unit is used to form a mounting base for a through-type assembly, which is mounted on the oil tank via the flange fixing unit.

[0019] A protective unit is used to protect the control and interaction unit, the connector assembly, and the external fiber optic extension line from damage, and includes a protective box assembly and a protective cover assembly. The protective box assembly is located away from the protective cover assembly. A portion of the structure of the control and interaction unit and the external fiber optic extension line is respectively located inside the protective box assembly, and another portion of the structure of the connector assembly and the external fiber optic extension line is respectively located inside the protective cover assembly.

[0020] Preferably, the fiber optic temperature sensor includes a polyimide fiber core, an exposed temperature probe with built-in rare-earth fluorescent material, a first ST connector, and a polytetrafluoroethylene (PTFE) sheath. The exposed temperature probe and the first ST connector are respectively connected to the two ends of the polyimide fiber core. The PTFE sheath is fitted onto the surface of the polyimide fiber core, and the exposed temperature probe is located at the bottom end of the PTFE sheath.

[0021] Preferably, the control and interaction unit includes a fiber optic temperature measurement host, a signal processing submodule, and a communication submodule. The signal processing submodule and the communication submodule are both integrated inside the fiber optic temperature measurement host, and the three are electrically connected and interact with each other through the PCB circuit board inside the host.

[0022] Preferably, the fiber optic temperature measurement host includes a microprocessor, an LCD screen, a 1-8 bit DIP switch, two relay output units, and a power management unit. The LCD screen, the 1-8 bit DIP switch, and the two relay output units are electrically connected to the microprocessor, and the microprocessor, the LCD screen, the 1-8 bit DIP switch, and the two relay output units are electrically connected to the power management unit.

[0023] The signal processing submodule includes a fluorescence signal receiving circuit, a photoelectric conversion unit, a temperature algorithm processor, and a multi-channel data acquisition module. The external optical fiber extension line and the photoelectric conversion unit are respectively connected to the fluorescence signal receiving circuit, and the photoelectric conversion unit and the temperature algorithm processor are respectively electrically connected to the multi-channel data acquisition module.

[0024] The communication submodule includes an RS485 interface circuit, a 4-20mA analog output interface circuit, a USB debugging interface circuit, and a signal isolation unit. The RS485 interface circuit, the 4-20mA analog output interface circuit, and the USB debugging interface circuit are electrically connected to the microprocessor, and the signal isolation unit is connected in series between the microprocessor and the RS485 interface circuit and the 4-20mA analog output interface circuit.

[0025] Preferably, the through-hole assembly includes a through-hole body, double nuts, and a first sealing ring. The double nuts are threaded onto the surface of the through-hole body, and the top of the double nuts contacts the flange fixing unit. The through-hole body has a first groove adapted to the first sealing ring on the side facing the flange fixing unit. The first sealing ring is embedded in the inner cavity of the first groove. The through-hole body is mated with a first ST connector.

[0026] Preferably, the external optical fiber extension line includes a quartz optical fiber core, a second ST connector with a step-down converter, and a Teflon sheath. The second ST connector is connected to one at each end of the quartz optical fiber core, and the Teflon sheath is fitted onto the surface of the quartz optical fiber core. The connector body and the fluorescent signal receiving circuit are respectively connected to the two second ST connectors.

[0027] Preferably, the flange fixing unit includes a flange ring, a flange plate, and a second sealing ring. The flange ring is welded to the inner wall of the transformer tank. The flange plate is installed on the flange ring with screws. A second groove is formed on the side of the flange ring facing the flange plate. The second sealing ring is embedded in the inner cavity of the second groove and fits against the bottom of the flange plate.

[0028] The flange has a through hole for the penetrator body to pass through. The inner diameter of the through hole is adapted to the outer diameter of the penetrator body. Several through holes are equally spaced in a ring on the flange. The first sealing ring fits against the top of the flange. The double nut is located in the inner cavity of the flange ring and is in contact with the flange.

[0029] Preferably, the protective box assembly includes a box body and a box door. The control and interaction unit is installed in the inner cavity of the box body. The bottom of the box body has a plurality of first wiring holes. The box door is hinged to one side of the box body. The surface of the box door is fitted with a glass observation window.

[0030] Preferably, the protective cover assembly includes a cover body, a cover, and gaskets. The bottom of the cover body has an integrally formed outer edge, which is installed on a flange by screws. The top of the cover body has an integrally formed inner edge, and the cover is installed on the inner edge by screws. One gasket is placed between the cover and the inner edge, and between the outer edge and the flange. Three second wiring holes are provided on one side of the surface of the cover body. Waterproof connectors are installed in the inner cavities of the second wiring holes and the first wiring holes, respectively. The external optical fiber extension cable passes through the corresponding second wiring holes and the first wiring holes in sequence to enter the housing.

[0031] Preferably, the through-hole body, double nuts, flange ring, and flange are all made of 316 stainless steel, the cover and cover are all made of 304 stainless steel, the first sealing ring and the second sealing ring are both fluororubber sealing rings, and the gasket is a silicone rubber sealing gasket.

[0032] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0033] 1. This invention, through a complete system design comprising a fiber optic temperature sensor, a control and interaction unit, a transmission and transfer unit, a flange fixing unit, and a protection unit, achieves a closed-loop process from temperature sensing and signal transmission to data processing and alarm control. The fiber optic temperature sensor directly contacts the winding hotspot and measures temperature based on the fluorescence decay time principle (not light intensity), solving the problems of large errors in traditional indirect calculation methods and poor anti-interference capabilities of electrical sensors. The system is integrated, resulting in more accurate monitoring.

[0034] 2. This invention uses a polyimide fiber optic core and a polytetrafluoroethylene sheath for the fiber optic temperature sensor, which has no metal parts, can withstand high voltage, and is completely immune to EMI / RFI. The signal isolation unit (optical isolation) of the control and interaction unit further blocks external interference, ensuring stable operation in a strong electromagnetic environment. Its safety far exceeds that of existing electrical temperature measurement devices, significantly improving anti-interference and safety.

[0035] 3. This invention forms a double seal with the first and second sealing rings through double nuts, ensuring low-loss transmission of optical signals; the flange is made of 316 stainless steel, which is resistant to transformer oil corrosion, solving the problems of sealing failure and optical signal attenuation in existing devices, and the sealing performance is suitable for oil immersion environments.

[0036] 4. This invention adopts a split structure for the protection unit. The protection box assembly (IP55 protection level) is equipped with a control and interaction unit, which facilitates remote observation and operation. The protective cover assembly (304 stainless steel) covers the through-type assembly and the external fiber optic connector, which is rainproof and dustproof. Compared with the single protection structure of the prior art, this invention extends the equipment life and reduces the maintenance frequency. The protection design improves the equipment life and maintenance convenience.

[0037] 5. This invention uses a fiber optic temperature sensor to measure temperature based on fluorescence decay time, eliminating the need for periodic calibration and reducing maintenance costs; the flange can have multiple through holes, supporting multi-channel expansion and adapting to transformers of different capacities, offering superior versatility compared to existing fixed-channel designs, and providing strong calibration-free and expandable capabilities. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention;

[0040] Figure 2 This is a schematic diagram of the structure of the fiber optic temperature sensor, the transmission and conversion unit, and the flange fixing unit according to an embodiment of the present invention;

[0041] Figure 3 This is an exploded view of the structure of the through-hole assembly and the flange fixing unit according to an embodiment of the present invention;

[0042] Figure 4 This is an exploded view of the flange fixing unit and protective cover assembly according to an embodiment of the present invention. Figure 1 ;

[0043] Figure 5 This is an exploded view of the flange fixing unit and protective cover assembly according to an embodiment of the present invention. Figure 2 ;

[0044] Figure 6 This is an exploded view of the structure of the penetrator assembly according to an embodiment of the present invention;

[0045] Figure 7This is a schematic diagram of the structure of the fiber optic temperature sensor according to an embodiment of the present invention;

[0046] Figure 8 This is a schematic diagram of the structure of the external optical fiber extension line in an embodiment of the present invention.

[0047] In the diagram: 100, fiber optic temperature sensor; 110, polyimide fiber optic core; 120, exposed temperature probe; 130, first ST connector; 140, PTFE sheath;

[0048] 200. Control and interaction unit;

[0049] 300. Transmission and switching unit; 310. Through-connector assembly; 311. Through-connector body; 3111. First groove; 312. Double nut; 313. First sealing ring; 320. External fiber optic extension cable; 321. Quartz fiber optic core; 322. Second ST connector; 323. Teflon sheath;

[0050] 400, Flange fixing unit; 410, Flange ring; 411, Second groove; 420, Flange; 421, Through hole; 430, Second sealing ring;

[0051] 500, Protective unit; 510, Protective box assembly; 511, Box body; 5111, First wiring hole; 512, Box door; 5121, Glass observation window; 520, Protective cover assembly; 521, Cover body; 5211, Outer edge; 5212, Inner edge; 5213, Second wiring hole; 522, Cover; 523, Gasket. Detailed Implementation

[0052] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0053] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0054] Example 1

[0055] like Figures 1-8 As shown, the transformer winding fluorescent fiber optic temperature measuring device according to an embodiment of the present invention includes a fiber optic temperature sensor 100, a control and interaction unit 200, a transmission and conversion unit 300, a flange fixing unit 400, and a protection unit 500, wherein:

[0056] The fiber optic temperature sensor 100 directly contacts the hot spot of the transformer winding, receives excitation light, and returns a temperature-related fluorescence signal, achieving temperature sensing without metal intervention. The control and interaction unit 200 centrally controls the temperature measurement process of each channel, displays temperature data in real time, and triggers an over-temperature alarm. The transmission and conversion unit 300 is used to realize the sealed conversion of optical fibers inside and outside the transformer tank and to extend the signal transmission distance. It includes a through-type assembly 310 and an external optical fiber extension line 320. The through-type assembly 310 is connected between the external optical fiber extension line 320 and the fiber optic temperature sensor 100. The external optical fiber extension line 320 is connected between the control and interaction unit 200 and the through-type assembly 310. The fiber optic temperature sensor 100 passes through the through-type assembly 310 and is installed in the transformer tank wall. The flange fixing unit 400 is used to form the mounting base of the through-type assembly 310. The through-type assembly 310 is mounted on the oil tank via the flange fixing unit 400; the protection unit 500 is used to protect the control and interaction unit 200, the through-type assembly 310, and the external fiber optic extension line 320 from damage, and includes a protection box assembly 510 and a protection cover assembly 520. The protection box assembly 510 is located away from the protection cover assembly 520. Parts of the structure of the control and interaction unit 200 and the external fiber optic extension line 320 are respectively located inside the protection box assembly 510, and other parts of the structure of the through-type assembly 310 and the external fiber optic extension line 320 are respectively located inside the protection cover assembly 520. An integrated temperature measurement system is provided to solve the problems of functional dispersion and low reliability caused by existing technologies that only focus on local structures such as a single probe. It achieves full-process coverage from temperature sensing to alarm control and is suitable for complex environments such as transformer oil immersion, high voltage, and strong electromagnetic fields.

[0057] Example 2

[0058] like Figures 1-8 As shown, the transformer winding fluorescent fiber optic temperature measuring device provided in this embodiment differs from that in Embodiment 1 in that:

[0059] The fiber optic temperature sensor 100 includes a polyimide fiber core 110, an exposed temperature probe 120 with built-in rare-earth fluorescent material, a first ST connector 130, and a polytetrafluoroethylene (PTFE) sheath 140. The exposed temperature probe 120 and the first ST connector 130 are respectively connected to the two ends of the polyimide fiber core 110. The PTFE sheath 140 is fitted onto the surface of the polyimide fiber core 110, and the exposed temperature probe 120 is located at the bottom end of the PTFE sheath 140. The fiber optic temperature sensor 100 has no metal parts, directly contacts the winding hot spot, is resistant to high voltage and oil immersion corrosion, and is immune to EMI / RFI. The PTFE sheath 140 enhances mechanical protection, and the exposed probe ensures rapid temperature measurement response, solving the problems of poor anti-interference and inability to directly contact hot spots in traditional sensors.

[0060] The control and interaction unit 200 includes a fiber optic temperature measurement host, a signal processing submodule, and a communication submodule. The signal processing submodule and the communication submodule are both integrated inside the fiber optic temperature measurement host. The three are electrically connected and interact with each other through the PCB circuit board inside the host. The internal electrical connection and data interaction through the PCB circuit board reduces external wiring and improves anti-interference capability. The integrated design reduces the size of the device, makes it easy to install, and solves the problem of existing technologies requiring external equipment to assist in data processing.

[0061] The fiber optic temperature measurement unit includes a microprocessor, an LCD screen, 1-8 bit DIP switches, two relay output units, and a power management unit. The LCD screen, DIP switches, and relay output units are electrically connected to the microprocessor, and the microprocessor, LCD screen, DIP switches, and relay output units are electrically connected to the power management unit. The microprocessor and LCD screen are connected via an LVDS low-voltage differential signal interface. The microprocessor outputs temperature data and display control commands (such as refresh rate and brightness adjustment) to drive the display screen to show the temperature values ​​of each channel in real time. The microprocessor and DIP switches are connected via a GP... The system uses general-purpose input / output pins. The states (on / off) of bits 1-8 of the DIP switches are directly fed back to the microprocessor for reading configuration information such as communication addresses. The microprocessor and relay output unit are connected via a relay driver circuit (such as the ULN2003 chip). The high and low level signals output by the microprocessor are amplified by the driver circuit to control the opening and closing of the relay contacts, realizing load control during over-temperature alarms. The power management unit converts AC220V to 5V and 3.3V DC power, which are connected to the microprocessor, display screen, and relays via power cords with fuses, providing a stable power supply for the entire fiber optic temperature measurement host.

[0062] The signal processing submodule includes a fluorescence signal receiving circuit, a photoelectric conversion unit, a temperature algorithm processor, and a multi-channel data acquisition module. An external fiber optic extension cable 320 and the photoelectric conversion unit are connected to the fluorescence signal receiving circuit, while the photoelectric conversion unit and the temperature algorithm processor are electrically connected to the multi-channel data acquisition module. The fluorescence signal receiving circuit and the external fiber optic extension cable 320 are connected via a pigtail. The fluorescence signal from the external fiber optic cable is input to the receiving circuit via the second ST connector 322. The optical lens in the receiving circuit focuses the signal, ensuring attenuated signal transmission. The fluorescence signal receiving circuit and the photoelectric conversion unit are connected via a coaxial shielded cable. The fluorescence signal (optical signal) captured by the receiving circuit is transmitted to the photodiode of the photoelectric conversion unit, converting it into a weak electrical signal (μV level). The photoelectric conversion unit and the multi-channel data acquisition module are connected via an operational amplifier. After amplification and filtering, the weak electrical signal is input to the ADC (analog-to-digital converter) of the data acquisition module, converting it into a digital signal. The multi-channel data acquisition module and the temperature algorithm processor are connected via an SPI bus. The digital signal is transmitted to the algorithm processor, which calculates the temperature value based on the fluorescence decay time algorithm and then transmits the temperature data to the host microprocessor via internal circuitry.

[0063] The communication submodule includes an RS485 interface circuit, a 4-20mA analog output interface circuit, a USB debugging interface circuit, and a signal isolation unit. The RS485 interface circuit, the 4-20mA analog output interface circuit, and the USB debugging interface circuit are electrically connected to the microprocessor. The signal isolation unit is connected in series between the microprocessor and the RS485 interface circuit and the 4-20mA analog output interface circuit. The microprocessor and the RS485 interface circuit are connected via a UART interface. The digital signal output by the microprocessor is converted into an RS485 differential signal by the MAX485 chip, and then transmitted through the signal isolation unit (optical coupler). After isolation (6N137), the signal is output from the RS485 interface (A+ / B- terminals) on the back panel of the fiber optic temperature measurement host. The microprocessor is connected to the 4-20mA analog output interface circuit via a DAC (digital-to-analog converter, such as AD5420). The digital temperature signal output by the microprocessor is converted into a 4-20mA current signal by the DAC, corresponding to a temperature range of -40℃ to 200℃, and is led out to external devices through terminal blocks. The microprocessor is connected to the USB debugging interface circuit via a CH340 chip (USB to UART). The microprocessor data is converted into a USB signal by the chip and output through the USB port on the side panel of the fiber optic temperature measurement host. The Type-B interface allows for local debugging via computer (such as parameter configuration and data reading); the signal isolation unit is connected in series between the microprocessor and the RS485 and 4-20mA interfaces, achieving electrical isolation (isolation voltage ≥2500V) through optocouplers to prevent external high voltage or interference signals from entering the core circuit of the host; the microprocessor of the fiber optic temperature measurement host works in conjunction with relays and displays to achieve real-time display and over-temperature alarm, with timely response; the signal processing submodule improves temperature measurement accuracy through a process of fluorescent signal reception, photoelectric conversion, data acquisition, and algorithm processing; the communication submodule's multi-interface (RS485 / 4-20mA / USB) and signal isolation design ensure stable data transmission and adaptability to different monitoring systems.

[0064] The through-hole assembly 310 includes a through-hole body 311, double nuts 312, and a first sealing ring 313. The double nuts 312 are threaded onto the surface of the through-hole body 311, and the top of the double nuts 312 contacts the flange fixing unit 400. The through-hole body 311 has a first groove 3111 on the side facing the flange fixing unit 400, which is adapted to the first sealing ring 313. The first sealing ring 313 is embedded in the inner cavity of the first groove 3111. The through-hole body 311 is connected to the first ST connector 130. The double nuts 312 achieve mechanical fixing and sealing reinforcement. The first sealing ring 313 is resistant to oil pressure and has low light loss, solving the problems of sealing failure and light signal attenuation in existing devices, and ensuring long-term reliable operation in oil immersion environment.

[0065] The external fiber optic extension cable 320 includes a quartz fiber core 321, a second ST connector 322 with a step-down converter, and a Teflon sheath 323. One second ST connector 322 is connected to each end of the quartz fiber core 321. The Teflon sheath 323 is sleeved on the surface of the quartz fiber core 321. The connector body 311 and the fluorescent signal receiving circuit are respectively connected to the two second ST connectors 322. The Teflon sheath 323 enhances tensile strength and temperature resistance. The second ST connector 322 with a step-down converter design reduces signal reflection and extends the transmission distance, meeting the long-distance signal transmission requirements inside and outside the transformer tank.

[0066] The flange fixing unit 400 includes a flange ring 410, a flange 420, and a second sealing ring 430. The flange ring 410 is welded to the inner wall of the transformer tank. The flange 420 is installed on the flange ring 410 with screws. A second groove 411 is formed on the side of the flange ring 410 facing the flange 420. The second sealing ring 430 is embedded in the inner cavity of the second groove 411 and fits against the bottom of the flange 420.

[0067] The flange 420 has a through hole 421 for the through-hole body 311 to pass through. The inner diameter of the through hole 421 is adapted to the outer diameter of the through-hole body 311. Several through holes 421 are equidistantly arranged in a ring on the flange 420. The first sealing ring 313 fits against the top of the flange 420. The double nut 312 is located in the inner cavity of the flange ring 410 and contacts the flange 420. The flange ring 410 is welded and fixed to the flange 420 with screws, forming a double seal with the second sealing ring 430. This allows for modular installation of multiple through-hole components 310, meets different channel requirements, and solves the problems of poor versatility and insufficient sealing performance of existing flange structures.

[0068] The protective enclosure assembly 510 includes an enclosure 511 and an enclosure door 512. The control and interaction unit 200 is installed inside the enclosure 511. The bottom of the enclosure 511 has multiple first wiring holes 5111. The enclosure door 512 is hinged to one side of the enclosure 511, and a glass observation window 5121 is embedded in the surface of the enclosure door 512. The enclosure 511, with an IP55 protection rating, protects the control and interaction unit 200 from rain and dust. The glass observation window 5121 facilitates real-time temperature monitoring. The first wiring holes 5111 are adapted to waterproof connectors, improving installation flexibility and solving the problems of inconvenient maintenance and susceptibility to environmental damage in existing devices.

[0069] The protective cover assembly 520 includes a cover body 521, a cover 522, and gaskets 523. The bottom of the cover body 521 has an integrally formed outer edge 5211, which is screwed onto the flange 420. The top of the cover body 521 has an integrally formed inner edge 5212, which is screwed onto the inner edge 5212. One gasket 523 is placed between the cover 522 and the inner edge 5212, and between the outer edge 5211 and the flange 420. Three gaskets are provided on one side of the surface of the cover body 521. A second through hole 5213 is provided, and waterproof connectors are installed in the inner cavities of the second through hole 5213 and the first through hole 5111, respectively. The external fiber optic extension cable 320 passes through the corresponding second through hole 5213 and the first through hole 5111 in sequence to enter the housing 511. The 304 stainless steel cover 521 and the silicone rubber gasket form a sealed protection to protect the through connector assembly 310 and the second ST connector 322. The waterproof connector of the second through hole 5213 prevents water from entering the cable inlet, providing a high level of protection and extending the equipment life.

[0070] The main body 311, double nuts 312, flange ring 410, and flange 420 of the through-connector are all made of 316 stainless steel, while the cover 521 and cover 522 are made of 304 stainless steel. The first sealing ring 313 and the second sealing ring 430 are both fluororubber O-rings, and the gasket 523 is a silicone rubber gasket. The cover 521, cover 522, and gasket 523 all have irregular structures, which are composed of a part of a circular arc structure and another part of a planar structure. The second through hole 5213 is opened on the planar structure. 316 stainless steel is resistant to transformer oil corrosion, 304 stainless steel balances protection and cost, fluororubber sealing rings are resistant to oil temperature, and silicone rubber gaskets enhance sealing elasticity, ensuring the material stability of the device in long-term high-temperature and oil-immersion environments, and solving the problem of short service life caused by the lack of corrosion resistance of existing materials.

[0071] The temperature algorithm processor executes a weighted least squares fitting algorithm for fluorescence decay time, and its objective function is defined as:

[0072]

[0073] Among them, the weighting factor w i Dynamically adjusted to:

[0074] In the formula:

[0075] I(t i ):t i Fluorescence intensity sampled value at time;

[0076] A: Fluorescence signal amplitude, B: Background noise offset;

[0077] τ: The fluorescence lifetime to be solved (which is proportional to temperature) (Linear inverse proportional relationship);

[0078] SNR(t i ): Signal-to-noise ratio at time ti (calculated in real time by the multi-channel data acquisition module);

[0079] Measurement variance (system preset);

[0080] k: Noise immunity coefficient (configurable via 1-8 bit DIP switches, k∈{1,2,3})

[0081] The technical principle of the equation:

[0082] 1. Dynamic weight design

[0083] The drawback of traditional methods: Existing technologies (such as CN214096419U) use fixed-weight least squares fitting, which is prone to deviation in τ calculation due to noise under strong electromagnetic interference.

[0084] This solution is innovative:

[0085] weight w i With signal-to-noise ratio (SNR) (t) i The signal-to-noise ratio (SNR) is proportional to the power of k, and higher weights are assigned to periods with high SNR (e.g., ...). Figure 1 (Initial attenuation phase after the excitation light is turned off) to enhance the effective signal;

[0086] When SNR(t) i If the signal is below a threshold (such as a signal that has decayed later), the weight is automatically reduced to suppress noise interference.

[0087] Adaptability of parameter k: The noise immunity strength can be set by DIP switch (e.g., k=1 to maintain sensitivity when the transformer is unloaded, and k=3 to enhance the immunity when the load changes suddenly).

[0088] 2. Multi-channel collaborative calibration

[0089] After calculating τ independently for each channel, cross-validation is performed using temperature consistency constraints:

[0090]

[0091] T j Temperature of channel j Average temperature across all channels;

[0092] ΔT th Threshold (default 5℃), channels exceeding the limit will automatically trigger resampling;

[0093] Addressing the pain points of existing technologies: avoiding single-point failures and reducing the frequency of manual calibration (the background technology in the manual indicates that existing devices require periodic calibration).

[0094] Implementation examples and results:

[0095] Workflow:

[0096] 1. Signal Acquisition: The photoelectric conversion unit outputs a fluorescence intensity sequence I(t1), I(t2), ..., I(t... N (N = 200 sampling points).

[0097] 2. Dynamic weight calculation:

[0098] Real-time computing (σ noise (Taken from background noise without excitation);

[0099] according to Generate weight sequence ( (Based on the system noise model preset).

[0100] 3. Fluorescence lifetime calculation:

[0101] Solve the objective function minimization problem to obtain the optimal value of τ;

[0102] Substitute into the calibration formula Output temperature (a, b are probe calibration parameters).

[0103] 4. Multi-channel verification:

[0104] If a certain channel The microprocessor controls the channel to be resampled and triggers an alarm.

[0105] Technical Effects Table:

[0106]

[0107]

[0108] Differences from existing technologies:

[0109] 1. Non-universal formula: Current fluorescence lifetime thermometry only uses I(t) = Ae -tτ The previous one did not introduce a dynamic weighting mechanism; this equation combines time-varying signal-to-noise ratio with adjustable noise immunity, which is the first of its kind.

[0110] 2. Technological synergy: Weighting factor w i It relies on the real-time noise analysis function of the multi-channel data acquisition module;

[0111] The k-value configuration is achieved through a patented "1-8 bit DIP switch".

[0112] This equation perfectly matches the advantages of "anti-interference", "calibration-free" and "multi-channel expansion".

[0113] The workflow of this invention is based on fluorescence fiber optic sensing technology and system co-design, as detailed below:

[0114] Temperature signal sensing: The signal processing submodule of the control and interaction unit 200 emits excitation light of a specific wavelength, which is transmitted to the exposed temperature sensing probe 120 of the fiber optic temperature sensor 100 (with built-in rare earth fluorescent material) via the external fiber extension line 320 and the through-hole assembly 310; after the excitation light excites the fluorescent material, it is turned off, and the fluorescent material releases a fluorescent signal (afterglow) related to the ambient temperature, which returns along the original path.

[0115] Signal transmission and conversion: The fluorescence signal is transmitted to the fluorescence signal receiving circuit of the signal processing submodule via the fiber optic temperature sensor 100, the through-type assembly 310, and the external fiber optic extension line 320. After being focused by the optical lens, it is transmitted to the photoelectric conversion unit and converted into a weak electrical signal. The multi-channel data acquisition module amplifies and filters the electrical signal and converts it into a digital signal through the ADC (analog-to-digital converter).

[0116] Temperature data processing: The temperature algorithm processor calculates the actual temperature value based on the fluorescence decay time (which is linearly related to temperature) and transmits it to the microprocessor of the control and interaction unit via the SPI bus; the microprocessor integrates multi-channel data, drives the LCD screen to display the temperature in real time, and compares it with a preset threshold.

[0117] Alarm and data interaction: If the temperature exceeds the threshold, the microprocessor triggers the relay output through the relay drive circuit to realize the over-temperature alarm (such as cutting off the load); at the same time, the communication submodule transmits data to the host computer through the RS485 interface (Modbus protocol) and 4-20mA analog interface, or performs local debugging through the USB interface. The signal isolation unit ensures that the data transmission is not affected by external interference.

[0118] System protection and sealing guarantee: The flange fixing unit 400 prevents transformer oil leakage through double sealing (first sealing ring 313, second sealing ring 430) and ensures the sealing of the signal transmission path; the protective box assembly 510 and the protective cover 520 respectively protect the control and interaction unit 200, the through-connector assembly 310 and the second ST connector, avoid the influence of environmental factors (rain, dust) and ensure the long-term stable operation of the system.

[0119] Through the above specific embodiments, those skilled in the art can easily implement the present invention. However, it should be understood that the present invention is not limited to the specific embodiments described above. Based on the disclosed embodiments, those skilled in the art can arbitrarily combine different technical features to achieve different technical solutions.

Claims

1. A fluorescent fiber optic temperature measuring device for transformer windings, characterized in that, include: The fiber optic temperature sensor directly contacts the hot spot of the transformer winding, receives the excitation light and returns a temperature-related fluorescence signal, thus realizing temperature sensing without metal intervention. The control and interaction unit centrally controls the temperature measurement process of each channel, displays temperature data in real time, and triggers over-temperature alarms. The transmission and switching unit is used to realize the sealed switching of optical fibers inside and outside the transformer tank and to extend the signal transmission distance. It includes a through-hole assembly and an external optical fiber extension line. The through-hole assembly is connected between the external optical fiber extension line and the optical fiber temperature sensor. The external optical fiber extension line is connected between the control and interaction unit and the through-hole assembly. The optical fiber temperature sensor is installed in the transformer tank wall through the through-hole assembly. A flange fixing unit is used to form a mounting base for the pier assembly, which is mounted on the tank via the flange fixing unit. The protective unit is used to protect the control and interaction unit, the through-type assembly and the external fiber optic extension line from damage, and includes a protective box assembly and a protective cover assembly. The protective box assembly is located away from the protective cover assembly. A portion of the structure of the control and interaction unit and the external fiber optic extension line is respectively located inside the protective box assembly, and another portion of the structure of the through-type assembly and the external fiber optic extension line is respectively located inside the protective cover assembly. The fiber optic temperature sensor includes a polyimide fiber core, an exposed temperature probe with embedded rare-earth fluorescent material, a first ST connector, and a polytetrafluoroethylene (PTFE) sheath. The exposed temperature probe and the first ST connector are respectively connected to the two ends of the polyimide fiber core. The PTFE sheath is fitted onto the surface of the polyimide fiber core, with the exposed temperature probe located at the bottom end of the PTFE sheath. The control and interaction unit includes a fiber optic temperature measurement host, a signal processing submodule, and a communication submodule. The signal processing submodule and the communication submodule are both integrated inside the fiber optic temperature measurement host. The three are electrically connected and interact with each other through a PCB circuit board inside the host. The fiber optic temperature measurement host includes a microprocessor, an LCD screen, a 1-8 bit DIP switch, two relay output units, and a power management unit. The LCD screen, the 1-8 bit DIP switch, and the two relay output units are electrically connected to the microprocessor. The DIP switch and two relay output units are electrically connected to the power management unit. The signal processing submodule includes a fluorescence signal receiving circuit, a photoelectric conversion unit, a temperature algorithm processor, and a multi-channel data acquisition module. An external fiber optic extension cable and the photoelectric conversion unit are connected to the fluorescence signal receiving circuit, and the photoelectric conversion unit and temperature algorithm processor are electrically connected to the multi-channel data acquisition module. The communication submodule includes an RS485 interface circuit, a 4-20mA analog output interface circuit, a USB debugging interface circuit, and a signal isolation unit. The RS485 interface circuit, the 4-20mA analog output interface circuit, and the USB debugging interface circuit are electrically connected to the microprocessor. The signal isolation unit is connected in series between the microprocessor and the RS485 interface circuit and the 4-20mA analog output interface circuit. The temperature algorithm processor executes a weighted least squares fitting algorithm for fluorescence decay time, with its objective function defined as: Among them, the weighting factor w i Dynamically adjusted to ;I(t i ) for t i A represents the fluorescence intensity sample value at time t; A is the fluorescence signal amplitude; B is the background noise offset; τ is the fluorescence lifetime to be solved, and τ is proportional to temperature. Linear inverse proportional relationship; SNR(t) i () represents the signal-to-noise ratio at time ti; To measure variance; k is the noise immunity coefficient and k∈{1,2,3}; the temperature algorithm processor performs multi-channel collaborative calibration. If the temperature of a certain channel differs from the mean temperature of all channels by more than 5℃, then the channel will automatically trigger resampling. The drive assembly includes a drive body, double nuts, and a first sealing ring. The double nuts are threaded onto the surface of the drive body, and the top of the double nuts contacts the flange fixing unit. A first groove adapted to the first sealing ring is opened on the side of the drive body facing the flange fixing unit. The first sealing ring is embedded in the inner cavity of the first groove. The drive body is mated with the first ST connector.

2. The transformer winding fluorescent fiber optic temperature measuring device according to claim 1, characterized in that: The external fiber optic extension cable includes a quartz fiber core, a second ST connector with a step-down converter, and a Teflon sheath. There is one second ST connector at each end of the quartz fiber core. The Teflon sheath is fitted onto the surface of the quartz fiber core. The connector body and the fluorescent signal receiving circuit are respectively connected to the two second ST connectors.

3. The transformer winding fluorescent fiber optic temperature measuring device according to claim 2, characterized in that: The flange fixing unit includes a flange ring, a flange plate, and a second sealing ring. The flange ring is welded to the inner wall of the transformer tank. The flange plate is installed on the flange ring with screws. A second groove is formed on the side of the flange ring facing the flange plate. The second sealing ring is embedded in the inner cavity of the second groove and fits against the bottom of the flange plate. The flange has through holes for the piercing device body to pass through. The inner diameter of the through holes is matched with the outer diameter of the piercing device body. Several through holes are equidistantly arranged in a ring on the flange. The first sealing ring fits against the top of the flange. The double nuts are located in the inner cavity of the flange ring and are in contact with the flange.

4. The transformer winding fluorescent fiber optic temperature measuring device according to claim 3, characterized in that: The protective enclosure assembly includes an enclosure body and an enclosure door. The control and interaction unit is installed in the inner cavity of the enclosure body. Multiple first wiring holes are provided at the bottom of the enclosure body. The enclosure door is hinged to one side of the enclosure body, and a glass observation window is embedded in the surface of the enclosure door.

5. The transformer winding fluorescent fiber optic temperature measuring device according to claim 4, characterized in that: The protective cover assembly includes a cover body, a cover, and gaskets. The bottom of the cover body has an integrally formed outer edge, which is installed on the flange by screws. The top of the cover body has an integrally formed inner edge, and the cover is installed on the inner edge by screws. One gasket is placed between the cover and the inner edge, and between the outer edge and the flange. Three second wiring holes are opened on one side of the surface of the cover body. Waterproof connectors are installed in the inner cavities of the second wiring holes and the first wiring holes, respectively. External fiber optic extension cables are sequentially passed through the corresponding second wiring holes and the first wiring holes into the enclosure.

6. The transformer winding fluorescent fiber optic temperature measuring device according to claim 5, characterized in that: The body of the through-hole connector, double nuts, flange ring, and flange are all made of stainless steel. The cover and cover are also made of stainless steel. The first and second sealing rings are fluororubber sealing rings, and the gaskets are silicone rubber sealing gaskets.

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