【作者】 朱祖清；

【导师】 林国庆；

【作者基本信息】 福州大学 ， 电机与电器， 2004， 硕士

【摘要】 绝缘油的介质损耗因数、体积电阻率测量，是判断绝缘油的劣化与污染程度的有效预防性试验，是保障变压器、油断路器等充油电力设备安全运行的重要手段。然而，目前所使用的绝缘油介质损耗因数、体积电阻率测试系统存在着测量精度低、测量结果重复性不好、控温系统不能满足控温要求、操作不便等缺陷，针对这一现状，本文对绝缘油介损及体积电阻率一体化测试系统进行了研究。 对油介损及体积电阻率测量时，首先要在15分钟内将油温从室温升到90℃并保持恒定，因此对恒温控制系统要求较高。本文对恒温控制系统进行了研究，提出了以中频感应加热方式取代原有的电阻炉加热方式，设计了一种分段控制的积分分离式数字PID控制器来控制中频感应加热装置，并通过通信设计将恒温控制系统与介损及体积电阻率测试系统有机结合为一体机，实验结果表明该恒温控制系统完全满足介损及体积电阻率测试中的控温要求。 本文对现代介质损耗测量技术进行了分析与比较，采用过零鉴相比较法作为介质损耗测量方法，并结合外施高频脉冲技术、通道自校正技术、抗谐波技术，设计了高精度介质损耗测量电路，有效提高了介质损耗测量的精度，减小了测量误差。本文还对绝缘油体积电阻率测量电路进行了研究，针对体积电阻率测量中测量信号小且变化范围大的特点，设计了十六级自动换档的程控放大电路，以使很小的测量信号在大的变化范围内具有良好的线性度和测量精度，提高了体积电阻率测量结果的稳定性。 本文还设计了以AT89C55WD单片机为核心的控制处理系统的外围接口电路及其软件，对主要功能部分进行了分析，主要包括：键盘／液晶显示接口及界面设计、微型打印机接口、实时日历时钟芯片DS12C887、单片机与单片机及单片机与上位机的通信设计以及控制系统硬件抗干扰措施等。 最后采用所研制的绝缘油介损及体积电阻率一体化测试系统对不同油样进行了实测，并对实测结果进行了分析。更多还原

【Abstract】 The measurement of dielectric loss and volume resistivity is effective preventive tests to judge insulating oil isolation status of polluted and aging, and it’s important method of ensuring the safe operation of transformer and oil-filled circuit breaker, etc. However, the measuring systems of insulating oil dielectric loss and volume resistivity used at present exist the shortcoming of low accuracy, weak repeatability, inconvenience, and its thermostatic control system can’t meet the challenge. So, this paper researches the principle of measuring system of insulating oil dielectric loss and volume resistivity.During the measuring process, the insulating oil must be heated and kept at 90℃ in 15 minutes. Medium-frequency induction heating method is presented to instead of the electrical resistance furnace heating method on chapter 2, and a kind of subdivision-controlled integral-separated digital PID algorithm is designed to control the medium-frequency induction heating apparatus. The experience results indicated the reliability of this kind of thermostatic control system.The analysis and compare about modern dielectric loss measuring methods are presented on chapter 3, and the zero-crossing testing phase discrimination method is adapted as the measuring method of this measuring system. Furthermore, applied high frequency pulse technique, channel self-correction technique, anti-harmonic technique are used to increase accuracy and reliability of measurement. And a kind of 16-step automatic selective programmable amplifying circuit is designed in volume resistivity measuring circuit, so as to handle sampling little and broad signal.The control and disposal system with the core of microchip AT89C55WD is analyzed on chapter 4. Main function unit such as the interface circuit of LCD display and keyboard, the interface circuit of micro-printer, real time clock DS12C887, and hardware anti-jamming technique are discussed. Actual measurement result for different oil sample is analyzed and compared on chapter 5.更多还原