[0033] In order to make the purpose and features of the present invention more comprehensible, the specific implementation manners of the present invention will be further described below in conjunction with the accompanying drawings. However, the present invention can be implemented in different forms and should not be limited to the described embodiments. Moreover, in the case of no conflict, the embodiments in the present application and the features in the embodiments are allowed to be combined or replaced with each other. The advantages and features of the present invention will become clearer in conjunction with the following descriptions.
[0034] It should be noted that all the drawings are in a very simplified form and use imprecise scales, and are only used to facilitate and clearly assist the purpose of illustrating the embodiments of the present invention.
[0035] It should also be stated that the purpose of numbering the steps in the present invention is to facilitate reference, not to limit the sequence. For individual steps that need to be emphasized in order, special instructions will be given in special text in the text.
[0036] In order to test the anti-oxidation ability of transformer oil during use, that is, the oxidation stability, it is necessary to conduct a long-term high-temperature oxidation test on transformer oil without any additives or only a small amount of inhibitors, and measure the post-oxidation after the test. The volatile acid value of transformer oil, oil-soluble acid value, sediment content and dielectric loss factor and other parameters are used to evaluate the anti-oxidation ability of the transformer oil.
[0037] Please refer to figure 1. figure 1 It is an exemplary control relationship block diagram of the system proposed by the present invention for testing the oxidation stability of transformer oil. It can be seen from the figure that the system for testing the oxidation stability of transformer oil proposed in this embodiment includes: a heating bath 1 , a flow controller 5 , a main temperature controller 3 , a monitoring temperature controller 4 and a security unit 2 .
[0038] The test temperature of the heating bath 1 is controlled and monitored by the main temperature controller 1. According to relevant standards in the industry, the test temperature is 120±0.5°C. In this embodiment, a high-precision temperature controller is used, and the test temperature can be controlled at 120±0.2°C. The main temperature controller 1 controls the heating equipment to heat the heating bath 1. When the temperature reaches 120°C, the main temperature controller 1 monitors the temperature. When the main temperature controller 1 detects that the temperature deviation exceeds ±0.2°C, the main temperature controller 1 Thermostat 1 sounds an alarm requiring manual intervention. The preset temperature deviation ±0.2°C is the first warning temperature at which the main temperature controller 1 needs to issue an alarm.
[0039] The monitoring thermostat 4 can be regarded as a protective measure for synchronizing with the main thermostat 1 . The monitoring thermostat 4 and the main thermostat 1 monitor the temperature of the heating bath 1 synchronously, and continue to monitor the temperature of the heating bath 1 after the main thermostat 1 sends out an alarm and stops temperature control. If the temperature of the heating bath 1 continues to be high If it does not fall, and exceeds the second warning temperature, then the monitoring thermostat 4 will give an alarm first, and if the response is not obtained within a certain period of time, then the test work of the system will be stopped to ensure the quality and safety of the test. The second early warning temperature is the same as the aforementioned first early warning temperature, which is a deviation value based on the set test temperature. Generally, the second early warning temperature can be set to ±0.2°C, ±0.5°C, ±1°C, etc.
[0040] The security unit 2 plays the role of absolute temperature control and can be understood as an emergency switch. Once the temperature of the heating bath 1 exceeds the limit temperature, the security unit 2 directly cuts off the power supply of the testing system and stops the testing work.
[0041] The heat conducting material of the heating bath 1 is preferably aluminum alloy, and the outer layer of the aluminum alloy material can also be covered with a layer of insulation layer to slow down the loss of heat. In order to achieve a better effect, combined with the existing thermal insulation material, the thickness of the thermal insulation layer is preferably greater than 5cm.
[0042] Further, the heating bath 1 is provided with a temperature sensor group 11 and a limit controller 12 .
[0043] In order to uniformly monitor the temperature of each place in the heating bath 1 , the temperature sensor group 11 may include one or more temperature sensors arranged at various places in the heating bath 1 . The temperature sensor group 11 is respectively connected with the main temperature controller 3 and the monitoring temperature device 4, and the main temperature controller 3 and the monitoring temperature device 4 independently and separately read the temperature data collected by the temperature sensor group 11, and comprehensively judge the current temperature. Whether the temperature meets the requirements of the test temperature, the first alarm temperature, and the second alarm temperature.
[0044] The limit controller 12 is directly connected with the security unit 2. When the limit controller 12 detects that the temperature of the heating bath 1 is higher than the limit temperature, the limit controller 12 sends out an alarm to prompt manual intervention, and the security unit 2 directly cuts off the test system. power, stop the test work.
[0045] The flow controller 5 is used to control the flow rate of the air flow flowing into the test tube filled with transformer oil.
[0046] In order to illustrate the structure of the oxidation stability test system more clearly, it can be combined with figure 2 to understand. figure 2 Shown is a schematic outline of an embodiment of the present invention. In the figure, the panel area presents the panel of the 8-way flow controller 5 . Correspondingly, 8 sets of support devices (details not shown) for test tube insertion are provided in the area of the heating bath 1 . During the test, a maximum of 8 sets of oxidation tubes-absorption tubes can be inserted, and the oxidizing gas flowing into each set of oxidation tubes-absorption tubes is independently controlled by 8 flow controllers 5 . The oxidizing gas can be pure oxygen or filtered air. The panel area is also provided with the panel of the main temperature controller 3, the panel of the monitoring thermostat 4, the power switch 8, the monitoring switch 9, and the safety switch 10.
[0047] like figure 2 As shown, the heating bath 1 is provided with 8 supporting frames of the oxidation tube 6 (only one is shown in the figure), and the transformer oil to be tested is contained in the oxidation tube 6, and the oxidation gas is passed into the transformer oil through a hose. , the flow rate of the oxidizing gas is adjusted and controlled by a flow controller 5 . The oxidation pipe 6 is also connected with the absorption pipe 7 through a hose. The gas generated due to the oxidation reaction in the oxidation tube 6 passes through the hose into the absorption tube 7 filled with pure water, so that the gas is dissolved in the pure water.
[0048] figure 2 Also schematically draw a sensor in the temperature sensor group 11, this sensor is an electronic thermometer, it is connected with the main temperature controller 3 and the monitoring temperature device 4 respectively, to the main temperature controller 3 and the monitoring temperature device 4 The current temperature of the heating bath 1 is provided, and after the main temperature controller 3 and the monitoring temperature controller 4 comprehensively calculate the data of the temperature sensor group 11, the current temperature is displayed on the panel.
[0049] Considering the reliability of the thermometer, a mercury thermometer 41 is added in this embodiment. The mercury thermometer 41 is suspended in a test tube filled with transformer oil, which is set in the heating bath 1 in the same manner as the oxidation tube 6 . Theoretically, the reading of the mercury thermometer 41 should be the same as the data displayed on the panels of the main thermostat 3 and the monitoring thermostat 4 . Testers can read the readings of the mercury thermometer 41 from time to time, and compare it with the readings on the panel to confirm whether the current work of the temperature sensor group 11 is reliable and credible.
[0050] A method for using the above-mentioned oxidation stability testing system comprises the following steps:
[0051] S1. Turn on the power switch 8 of the test system, and set the heat preservation temperature on the main temperature controller 3 (more precisely, the panel).
[0052] S2. Turn on the monitoring switch 9 and the safety switch 10 within 10 minutes of step S1.
[0053] S3. After the temperature of the heating bath 1 stabilizes (generally takes more than 30 minutes), open the gas channel (the gas pressure in the channel needs to be adjusted in advance).
[0054] S4. Adjust the flow controller 5 so that the flow rate of the oxidizing gas passing into each group of oxidizing tubes-absorbing tubes meets the test requirements.
[0055] Further, in step S2, if the switch of the monitoring thermostat 4 and the security unit 2 is not turned on within 10 minutes, the main thermostat 3 will give an alarm. ——", after the alarm lasts for 5 minutes, if there is no manual intervention, the main temperature controller 3 cuts off the power supply of the test system and stops the test work, so as to avoid occasional misoperation.
[0056] In order to ensure the safety of the test, the above-mentioned oxidation stability testing system also includes an alarm method, including the following steps:
[0057] B1. When the temperature of the heating bath 1 exceeds the first warning temperature, in this embodiment, it is set that when the temperature of the heating bath 1 exceeds the preset heat preservation temperature and the deviation exceeds ±0.2°C, the main temperature controller 3 will alarm; In this embodiment, the alarm sound is set to be a continuous "beep, beep" sound and the corresponding indicator light is flickering.
[0058] B2. When the alarm of the main temperature controller 3 continues for 10 minutes without manual intervention, the main temperature controller 3 is closed, but the display content on the panel is kept. At this time, the monitoring thermostat 4 continues to work.
[0059] B3. When the main temperature controller 3 is closed for 10 minutes, the temperature of the heating bath 1 fails to recover, or even continues to rise until it exceeds the second warning temperature. In this embodiment, when the temperature of the heating bath 1 exceeds the preset temperature When the deviation of the heat preservation temperature exceeds ±1°C, the monitoring thermostat 4 will give an alarm; in this embodiment, the alarm sound is set to be a short "beep beep" sound and the corresponding indicator light will flash.
[0060] B4. When the monitoring thermostat 4 alarm continues for 5 minutes and there is no manual intervention, then the monitoring thermostat 4 cuts off the power supply of the test system and stops the test work to reduce the temperature of the heating bath 1 as soon as possible.
[0061] Further, outside of steps B1-B4, if the temperature of the heating bath 1 exceeds the limit temperature, the security unit 2 cuts off the power supply of the testing system and stops the testing work urgently to ensure the safety of the testing.
[0062] The above-mentioned oxidation stability testing system can use multiple temperature monitoring to monitor the temperature of the testing system in real time, so as to improve the safety of the testing system. In addition, the test system is easy to use. After connecting the test tube, you only need to turn on the switch to start the test, which can save more labor costs and is suitable for various research and testing units.
[0063] Obviously, those skilled in the art can make various changes and modifications to the invention without departing from the spirit and scope of the invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.
