Multi-factor coupling dry-type transformer fire characteristic and fire extinguishing efficiency comprehensive test platform and test method

Abstract

The invention belongs to the technical field of transformer safety detection and fire prevention research, and particularly relates to a multi-factor coupling dry-type transformer fire characteristic and fire extinguishing efficiency comprehensive test platform and test method. Comprising a full-size transformer used for simulating a thermal-electric coupling effect under a real working condition; the insulating material module is arranged in the full-size transformer; the environment control room is used for accommodating the full-size transformer; the fire extinguishing system comprises a fire extinguishing agent tank and an injection pipeline laid in the environment control room; the data acquisition system comprises a high-speed camera-infrared thermal imaging system arranged around the environment control room; and the intelligent control center is in communication connection with the full-size transformer, the environment control room, the fire extinguishing system and the data acquisition system. The method can truly reproduce the forming, spreading and extinguishing process of the transformer fire, the experimental result is closer to the actual operation state, and the method has the advantages of being high in authenticity, good in repeatability, wide in application range and the like.

Description

Technical Field

[0001] This invention belongs to the field of transformer safety testing and fire prevention research technology, specifically involving a comprehensive test platform and test method for the fire characteristics and fire extinguishing efficiency of a dry-type transformer coupled with multiple factors. Background Technology

[0002] Dry-type transformers are core equipment in the power transmission and distribution system, and their operational safety directly affects the stability of the power grid. With the widespread application of dry-type transformers in critical scenarios such as high-rise buildings and data centers, the need for fire risk prevention and control is becoming increasingly urgent. Accurate combustion characteristic experimental data is the core basis for fire protection design, early warning system development, and fire extinguishing plan formulation. Dry-type transformers are widely used in urban power grids, high-rise buildings, and special locations due to their advantages such as fire resistance and explosion protection. However, their insulation systems still pose a fire risk under long-term electrical, thermal, and environmental stress.

[0003] Power safety is crucial to national welfare and economic and social development, and is an important component of national security. With the rapid advancement of urbanization and the digital economy, medium- and low-voltage distribution networks, as the "last mile" of power transmission, have become a core link in ensuring power supply for critical scenarios such as residential life, industrial and commercial production, and data centers. Therefore, the safety of distribution network equipment is a vital support for the safe and stable operation of the large power grid. Dry-type transformers, due to their small size, oil-free operation, and ease of maintenance, are the core transformer equipment in medium- and low-voltage distribution networks (10kV-35kV), widely used in building power distribution, industrial parks, data centers, and other locations. Their safe and stable operation is the foundation for the continuous power supply of the distribution network.

[0004] Dry-type transformers of 10kV and above mostly use epoxy resin cast insulation or Nomex paper insulation structures. During long-term operation, they are susceptible to aging and embrittlement of the insulation layer due to high temperature, humidity, and electric field effects. Furthermore, faults such as inter-turn short circuits and multi-point grounding of the core can easily cause localized overheating, leading to pyrolysis of the insulation material and the generation of hidden smoke (initially without obvious open flame). If not detected in time, the pyrolysis process can rapidly escalate into open flame combustion—such fires are characterized by "high concealment, rapid temperature rise, and rapid spread," directly damaging the transformer and potentially affecting surrounding power distribution equipment, causing regional power outages. Therefore, GB 50217-2018 "Design Standard for Cables in Power Engineering" stipulates that dry-type transformers installed in first-level load locations (such as hospitals, data centers, and important industrial plants) must be equipped with fire detection systems and fixed fire extinguishing devices.

[0005] Current research on the fire behavior and extinguishing mechanism of dry-type transformers mainly includes the following categories: (1) Scaled-down model experiments: Size scaling leads to distortion of magnetic field and thermal field distribution, with local electromagnetic loss and heat generation rate deviations exceeding 30%. (2) Single material combustion tests: These can only reflect the combustion characteristics at the material level and cannot reflect the discharge ignition mechanism of multi-layer insulation structures. (3) Numerical simulation methods: Due to limitations in material nonlinear parameters and aging model errors, the results generally deviate from actual measurements by more than 25%. Therefore, existing methods have shortcomings in terms of realistic coupled simulation, environmental controllability, fire extinguishing verification, and data consistency.

[0006] Through a survey of existing dry-type transformer fire test devices, the following problems were found: (1) Most experiments use scaled-down models, resulting in significant distortion of the magnetothermal field, which cannot reflect the actual internal coupling effect of the transformer; (2) Traditional experimental environmental conditions are simple and lack control of multiple parameters such as temperature and oxygen concentration, making it impossible to simulate complex operating scenarios; (3) There is a lack of verification methods that are linked with the fire extinguishing system, and the fire extinguishing and insulation restoration process cannot be systematically evaluated; (4) Data acquisition is separated at multiple points and the time is not synchronized, making it difficult to form a complete experimental closed loop. Summary of the Invention

[0007] The purpose of this invention is to provide a comprehensive test platform and test method for the fire characteristics and fire extinguishing efficiency of dry-type transformers coupled with multiple factors, so as to solve the problems existing in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a comprehensive test platform for the fire characteristics and extinguishing efficiency of dry-type transformers coupled with multiple factors, comprising: A full-size transformer, whose internal windings and core structure are consistent with the actual operating equipment, is used to simulate the thermo-electric coupling effect under real working conditions. An insulation material module, located inside the full-size transformer, includes various types of insulation material samples with different aging levels; The environmental control room is a closed experimental chamber used to house the full-size transformer and can perform closed-loop control of the temperature and humidity parameters inside the chamber. The fire extinguishing system includes a fire extinguishing agent tank and a spray pipeline laid in the environmental control room. The fire extinguishing agent tank stores fire extinguishing medium and can be sprayed in a directional manner through the spray pipeline. The data acquisition system includes a high-speed camera-infrared thermal imaging system set around the environmental control room to record the flame morphology, smoke flow and temperature field distribution during the experiment. The intelligent control center, which is communicatively connected to the full-size transformer, environmental control room, fire extinguishing system, and data acquisition system, is used to perform the following operations: The full-size transformer is controlled to simulate a preset fault scenario to ignite a fire source; The system receives signals from sensors in the environmental control room and automatically triggers the fire extinguishing system when preset conditions are met. Experimental data from various systems are collected and processed synchronously.

[0009] Preferably, the insulating material module includes at least one of epoxy resin, Nomex paper and glass fiber composite insulating material, and the insulating material sample has different aging levels of new, thermally aged or damply aged, and is installed between the winding layers of the full-size transformer through a detachable structure.

[0010] Preferably, the fire extinguishing system is a modular design, and the fire extinguishing agent tank can switch between storing and spraying at least one of carbon dioxide, dry powder, or heptafluoropropane as the extinguishing medium.

[0011] Preferably, the temperature control range of the environmental control room is 25°C to 80°C, and the humidity control range is 30%RH to 90%RH.

[0012] Preferably, the environmental control room is a temperature and humidity control chamber, comprising: The heating unit uses stainless steel heating tubes distributed in the side wall of the enclosure or in the air duct; The refrigeration unit uses a compressor refrigeration system; The humidification unit uses an ultrasonic humidifier; The dehumidification unit uses a refrigeration dehumidification method; In addition, a centrifugal fan and duct system for promoting air circulation and parameter uniformity within the chamber.

[0013] Preferably, the full-size transformer is pre-installed with a distributed fiber optic temperature sensor array and / or thermocouples to monitor its internal temperature distribution.

[0014] Preferably, the intelligent control center has multiple preset fire-inducing scenarios built in, including winding short circuit, overload or local overheating of the iron core, and can stimulate the initial heat source by controlling the electric heating element or arc discharge unit pre-installed inside the full-size transformer.

[0015] Preferably, after the open flame is extinguished, the intelligent control center automatically controls the insulation detection unit to perform insulation resistance testing on the windings of the full-size transformer, and integrates the data from the entire process to automatically generate a comprehensive experimental report.

[0016] This invention also discloses a test method for a comprehensive test platform for the fire characteristics and extinguishing efficiency of dry-type transformers coupled with multiple factors as described above, comprising the following steps: Installation steps: Secure the full-size transformer in the environmental control room and install the specified insulation material modules; Parameter setting steps: Set the experimental environmental parameters, fire scenario, and type of extinguishing medium through the intelligent control center; Experiment start-up steps: Start the system and simulate a transformer fault to ignite a fire source; Data acquisition steps: Temperature, flue gas, image, and gas concentration data are collected synchronously through the data acquisition system; Fire suppression linkage procedure: When a fire signal is detected exceeding a preset threshold, the fire suppression system is automatically triggered to extinguish the fire; Subsequent evaluation steps: After the flame is extinguished, the equipment insulation performance test will be performed automatically; Report generation steps: Process all collected data and automatically generate a comprehensive experimental report containing key charts and analytical conclusions.

[0017] The beneficial effects of this invention are as follows: By constructing a comprehensive test platform that is full-size, multi-factor controllable, and intelligently linked, this invention effectively solves key technical problems such as distortion in traditional scaled-down models, single experimental environment, and disconnect between fire extinguishing verification and other aspects. It can realistically and accurately reproduce the entire process of a dry-type transformer from fault ignition to fire spread, and automatically complete the fire extinguishing performance assessment and equipment insulation recovery test. This provides reliable and efficient data support and practical basis for in-depth research on transformer fire mechanisms, optimization of fire extinguishing system design, and formulation of scientific fire prevention standards.

[0018] This invention addresses the shortcomings of traditional experimental platforms where environmental parameters are uncontrollable by designing an independent environmental control room module. This module has the capability for closed-loop control of all parameters, including temperature and humidity, and can simulate various working conditions such as normal temperature and high temperature, providing a precise experimental environment for studying fire behavior under different environmental conditions.

[0019] The extinguishing agent container of this invention adopts a replaceable modular design, which can switch between CO2, dry powder, or heptafluoropropane media according to experimental needs, supporting multi-media synergistic fire extinguishing verification. The extinguishing agent spray pipeline is laid through the cable interlayer to the fire extinguisher in the cable of the key part of the experimental area. The spray direction and pressure are adjustable, realizing targeted fire extinguishing and rapid response for different fire situations.

[0020] The transformer prototype, fire extinguishing system, and control unit of this invention are all reusable, which effectively reduces experimental costs and improves safety, providing reliable experimental support for the formulation of transformer fire protection technical standards and the optimization of fire extinguishing strategies. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the full-size transformer structure in this invention; Figure 3 This is a schematic diagram of the fire extinguishing agent tank structure in this invention; Figure 4This is a schematic diagram of the environmental control room structure in this invention; In the diagram: 1. Full-size transformer; 2. Insulation material module; 21. Multiple sets of epoxy resin, Nomex paper and glass fiber composite insulation samples; 22. Thermocouple and fiber optic sensor; 23. Internal heating device; 3. Extinguishing agent container; 31. Extinguishing agent container body; 32. Carbon dioxide cylinder; 33. Dry powder cylinder; 34. Heptafluoropropane; 35. Spray pipe; 36. Pressure detection device; 4. Environmental control room; 41. Temperature detector; 42. Smoke detector; 43. Refrigeration dehumidifier; 44. Stainless steel heating element; 45. Cable-insulated nozzle; 5. Intelligent control center; 6. High-speed camera - infrared thermal imaging system. Detailed Implementation

[0022] The overall structure of the experimental platform of this invention is as follows: Figure 1-4 As shown, the experimental platform mainly consists of a full-size transformer 1, an insulation material module 2, a fire extinguishing agent tank 3, an environmental control room 4, an intelligent control center 5, and a high-speed camera-infrared thermal imaging system 6.

[0023] The functions of each component are as follows: Full-size transformer 1 is used to simulate the actual operating structure and thermal characteristics of a transformer; Insulation material module 2 is used to arrange new, aged, and different types of insulation samples; Fire extinguishing agent tank 3 is used to store and spray different types of fire extinguishing media; Environmental control room 4 is used to simulate the experimental environment of temperature and humidity; Intelligent control center 5 is used for system coordination and data acquisition and analysis; High-speed camera-infrared thermal imaging system 6 is used to capture the process of combustion spread and temperature change.

[0024] The full-size transformer 1 is a prototype of a large-capacity dry-type transformer, internally containing high- and low-voltage windings and a core structure, with several reserved areas for embedding insulation material. Connected to an external heating control module via cable terminals, it can trigger inter-turn short circuits or overload heating at set times to simulate fire sources induced by actual faults. Multiple thermocouples and fiber optic sensors are deployed on the transformer surface to monitor real-time temperature distribution.

[0025] like Figure 2As shown, the insulation material module 2 includes multiple sets of epoxy resin, Nomex paper, and glass fiber composite insulation samples 21, each with different aging levels (newly made, thermally aged for 72 hours, and damp-heat aged for 168 hours). The samples are fixed between the transformer winding layers using detachable insulation brackets, allowing for comparative analysis of the ignition point, combustion rate, and propagation behavior of different materials under the same operating conditions. These samples are fixed within the installation area using pluggable insulation brackets, enabling comparative analysis of different types and aging states of insulation materials under the same fire scenario. To accurately monitor the internal temperature, thermocouples and fiber optic sensors 22 are installed in key parts of the transformer (such as winding hot spots and the core surface). Simultaneously, an internal heating device 23 composed of nickel-chromium alloy heating elements is pre-installed to simulate localized overheating caused by winding overload or short circuit faults under controlled conditions.

[0026] The structure of fire extinguishing agent tank 3 is as follows Figure 3 As shown, it mainly includes a fire extinguishing tank 31, a carbon dioxide cylinder 32, a dry powder cylinder 33, a heptafluoropropane cylinder 34, a spray pipe 35, and a pressure detection device 36. The fire extinguishing tank 31 is connected to nozzles installed in the cable tray of the environmental control room 4 via the spray pipe 35, allowing it to spray carbon dioxide, dry powder, or heptafluoropropane towards the fire source area. It automatically opens when a fire signal is triggered, enabling rapid spraying of the extinguishing agent. The pressure detection device 36 monitors the pressure inside the tank in real time to ensure a stable and reliable fire extinguishing process.

[0027] like Figure 4 As shown, the environmental control room 4 is a sealed experimental chamber made of high-temperature resistant composite material. It integrates a complete environmental control system. Temperature control system: Includes stainless steel heating tube 44 for heating and compressor refrigeration unit for cooling. Forced air circulation in the cabin is achieved through centrifugal fan and air duct system to ensure uniform temperature. The temperature control range is 25℃ to 80℃.

[0028] Humidity control system: including ultrasonic humidifier and refrigerated dehumidifier 43, which achieves precise closed-loop control of humidity within the range of 30%RH to 90%RH through real-time feedback from the humidity sensor on the top.

[0029] Fire detection system: Multiple temperature detectors 41, smoke detectors 42 and cable nozzles 45 are installed at the four corners and top of the cabin to detect fire in real time.

[0030] The intelligent control hub 5 communicates with various sensors, heating units, fire extinguishing agent tanks 3, and infrared thermal imaging system 6 via industrial Ethernet. It has 12 built-in fire induction modes (winding short circuit, localized core overheating, insulation aging and breakdown, etc.), which can be loaded and started with a single button. The control interface enables signal distribution and automatic linkage; when the temperature or smoke concentration exceeds the threshold, it immediately issues a fire extinguishing command and records the response delay.

[0031] The high-speed camera-infrared thermal imaging system comprises three sets of high-speed cameras and an infrared thermal imager, deployed around the laboratory. The high-speed cameras capture flame morphology and smoke flow characteristics, while the infrared thermal imager measures the temperature field distribution. Both are synchronously connected to the data acquisition module of the intelligent control center, ensuring timestamp alignment between image and temperature data and guaranteeing consistency of multi-source information.

[0032] The workflow of the experimental platform in this embodiment is as follows: (1) Installation phase: Fix the full-size transformer 1 in the center of the environmental control room 4. Select and install the insulation material module 2 with a specific aging level and type according to the experimental purpose. Connect all sensor lines, fill the fire extinguishing agent tank 3 with the fire extinguishing medium selected for this experiment (such as heptafluoropropane), and ensure that it is connected to the control center 5.

[0033] (2) Parameter setting stage: In the operation interface of the intelligent control center 5, set the environmental parameters for this experiment (e.g., temperature 40℃, humidity 60%RH), select the fire simulation scenario (e.g., "low-voltage winding inter-turn short circuit"), and select the type of extinguishing medium.

[0034] (3) Experiment start-up and data acquisition phase: After operator confirmation, the system automatically starts. The intelligent control center 5 first drives the environmental control room 4 to reach the set temperature and humidity, and then triggers the pre-installed heating device 13 inside the transformer to simulate a fault heat source. At the same time, the high-speed camera-infrared thermal imaging system 6, temperature sensor 12, smoke detector 42, etc., all start up and begin to synchronously collect temperature, smoke concentration, visible light images, and infrared thermal imaging data.

[0035] (4) Firefighting coordination phase: When any temperature detector detects a temperature exceeding 200℃ (this threshold is adjustable), or the smoke concentration exceeds a preset safety limit, the intelligent control center 5 immediately sends a trigger signal to the corresponding solenoid valve of the extinguishing agent tank 3. The solenoid valve opens, and the extinguishing medium (such as heptafluoropropane) is rapidly sprayed towards the transformer fire source area through the spray pipe 35 and nozzle 45 to implement automatic fire extinguishing.

[0036] (5) Insulation testing stage: After the open flame is extinguished, the system automatically starts the insulation resistance tester to test the insulation resistance of the high and low voltage windings of the full-size transformer 1, quantifying the impact of the fire extinguishing measures on the electrical performance of the equipment.

[0037] (6) Data processing stage After the experiment, the intelligent control center 5 automatically performs timestamp alignment and fusion analysis on the multi-dimensional data collected throughout the process, and generates a comprehensive experimental report containing key information such as temperature field cloud map, flame spread sequence map, fire extinguishing response time, fire extinguishing efficiency and insulation recovery rate.

[0038] This invention, by constructing a full-scale, multi-factor controllable, and intelligently interconnected comprehensive test platform, has for the first time achieved closed-loop experimental simulation of the entire life cycle of dry-type transformers, from insulation aging, fault ignition, fire spread, intelligent fire suppression, to performance evaluation. The experimental data from this platform are authentic, reliable, and highly repeatable, providing indispensable technical support for in-depth research on the fire mechanism of dry-type transformers, optimization of fire suppression system design, and the formulation of scientific fire prevention standards.

[0039] It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention.

Claims

1. A comprehensive test platform for the fire characteristics and extinguishing efficiency of dry-type transformers coupled with multiple factors, characterized in that, include: A full-size transformer (1) whose internal winding and core structure are consistent with the actual operating equipment, is used to simulate the thermal-electric coupling effect under real working conditions. An insulation material module (2) is installed inside the full-size transformer (1) and includes various types of insulation material samples with different aging degrees; The environmental control room (4) is a closed experimental chamber used to house the full-size transformer (1) and to perform closed-loop control of the temperature and humidity parameters inside the chamber. The fire extinguishing system includes a fire extinguishing agent tank (3) and a spray pipeline laid in the environmental control room (4). The fire extinguishing agent tank (3) stores fire extinguishing medium and can be sprayed in a directional manner through the spray pipeline. The data acquisition system includes a high-speed camera-infrared thermal imaging system (6) set around the environmental control room (4) for recording the flame morphology, smoke flow and temperature field distribution during the experiment. The intelligent control center (5) is communicatively connected to the full-size transformer (1), the environmental control room (4), the fire extinguishing system, and the data acquisition system, and is used to perform the following operations: The full-size transformer (1) is controlled to simulate a preset fault scenario to ignite a fire source; It receives signals from sensors in the environmental control room (4) and automatically triggers the fire extinguishing system when preset conditions are met; Experimental data from various systems are collected and processed synchronously.

2. The comprehensive test platform according to claim 1, characterized in that, The insulating material module (2) includes at least one of epoxy resin, Nomex paper and glass fiber composite insulating material. The insulating material sample has different aging levels of new, thermally aged or damply aged, and is installed between the winding layers of the full-size transformer (1) through a detachable structure.

3. The comprehensive test platform according to claim 1, characterized in that, The fire extinguishing system is modularly designed, and the fire extinguishing agent tank (3) can switch between storing and spraying at least one of the following fire extinguishing media: carbon dioxide, dry powder, or heptafluoropropane.

4. The comprehensive test platform according to claim 1, characterized in that, The temperature control range of the environmental control room (4) is 25°C to 80°C, and the humidity control range is 30%RH to 90%RH.

5. The integrated test platform according to claim 4, characterized in that, The environmental control room (4) is a temperature and humidity controllable chamber, including: The heating unit uses stainless steel heating tubes distributed in the side wall of the enclosure or in the air duct; The refrigeration unit uses a compressor refrigeration system; The humidification unit uses an ultrasonic humidifier; The dehumidification unit uses a refrigeration dehumidification method; In addition, a centrifugal fan and duct system for promoting air circulation and parameter uniformity within the chamber.

6. The integrated test platform according to claim 1, characterized in that, The full-size transformer (1) is pre-installed with a distributed fiber optic temperature sensor array and / or thermocouples to monitor its internal temperature distribution.

7. The integrated test platform according to claim 1, characterized in that, The intelligent control center (5) has multiple preset fire-induced scenarios, including winding short circuit, overload or local overheating of the iron core, and can stimulate the initial heat source by controlling the electric heating element or arc discharge unit pre-installed inside the full-size transformer (1).

8. The integrated test platform according to claim 1, characterized in that, After the open flame is extinguished, the intelligent control center (5) automatically controls the insulation detection unit to perform insulation resistance testing on the windings of the full-size transformer (1) and integrates the full-process data to automatically generate a comprehensive experimental report.

9. A test method for a multi-factor coupled comprehensive test platform for the fire characteristics and fire extinguishing efficiency of dry-type transformers as described in any one of claims 1-8, characterized in that, Includes the following steps: Installation steps: Fix the full-size transformer (1) in the environmental control room (4) and install the specified insulation material module (2); Parameter setting steps: Set the environmental parameters, fire scenario and extinguishing medium type of the experiment through the intelligent control center (5); Experiment start-up steps: Start the system and simulate a transformer fault to ignite a fire source; Data acquisition steps: Temperature, flue gas, image, and gas concentration data are collected synchronously through the data acquisition system; Fire suppression linkage procedure: When a fire signal is detected exceeding a preset threshold, the fire suppression system is automatically triggered to extinguish the fire; Subsequent evaluation steps: After the flame is extinguished, the equipment insulation performance test will be performed automatically; Report generation steps: Process all collected data and automatically generate a comprehensive experimental report containing key charts and analytical conclusions.

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