高压试验用大功率变频电源及其计算机监控的研究与开发

【作者】 罗威；

【导师】 刘觉民；

【作者基本信息】 湖南大学 ， 电力系统及其自动化， 2002， 硕士

【摘要】 本文是以研究和开发高压试验用大功率变频电源及其计算机监控的实践为基础所进行的理论总结。文中就当前电力系统中的一些现场高压测试所面临的试验电源问题，这些试验包括变压器的局部放电和交流耐压试验、高压开关、高压交联电缆、GIS等的交流耐压试验，提出采用新型变频电源对高压设备进行测试。根据这些电力系统中的运行设备的特点：一方面导体对地的电容很大，另一方面导体的试验电压很高，深入研究了通过改变试验电压的频率，利用串联谐振和电磁感应等方法，很好的解决了所面临的电源问题。 文中对该变频电源的工作原理及主要硬件作了较详细的介绍；提出利用电力电子器件实现输出大功率。在回路中采用逐级放大的方法，将一个标准的正弦波信号通过前级放大，输出给后级，推动后级放大回路，主要的功率放大回路中采用大功率三极管并联实现功率放大输出。这样逐级放大得到一个功率很大电源，其最高输出功率可以达到300KW，而且能够调节频率和电压。为了保证被试品和人身安全，对于保护回路提出更高的要求，文中针对该变频电源的特点，利用快速可控硅的快速关断特性实现保护过程。采用了多种负反馈回路修正输出波形，使得输出电压波形的失真度很小；并且在电路中有效利用高压高频电容，减小了变频电源输出的电压对局部放电试验时的干扰。文中有效解决了大功率晶体管的在工作时的发热量较大的不利因素，提出改进散热信道和加大散热的接触面积等可行的方法。 在成功研制该变频电源后，还成功研究和开发了此设备的计算机监控系统，提高了该设备的使用过程中的安全性和自动化程度。采用计算机监控，不但能够实现远距离控制，而且更加方便操作。 变频电源在实践中得到多次使用，并很好的解决现场进行高压试验时所遇到的问题，证明了此装置的可靠性高、安全性好、实用性强。创造了较好的社会效益和经济效益。更多还原

【Abstract】 This paper used the problem on site in electric industry as a clue, and had a resolve according to engineering. This paper introduce, now in electrical system, the high-voltage tests include part-charge test for transformer, AC withstand voltage test for transformer, AC withstand voltage test for switch, AC withstand voltage test for HV cable, when the tests is on, the power sup--ply will be too poor. And this equipment have its characteristic: on the one hand its capacitance is too much from conductor to ground, on the other hand the test voltage is very high for the conductor. In this paper, we come up a way that uses variable frequency source to carry out these tests. And we had a resolve to the test availably. The way of using resonance in series for test can make the HV test easily in electric system.The paper analyses the principle of variable frequency source and brings forward that using electric electron technology make variable frequency output, and using high power dynatron that is parallel connection magnify power. In the circuit, using the way of step-by-step magnify, a normal sine wave signal through former circuit export for the next circuit, and this signal that have been magnified push the next step. The main magnify circuit use the method of high power dynatron that is parallel connection. So that, we will get a high exporting power source according to the step-by-step magnified circuit, the peak power output can reach 300Kw with variable frequency and variable voltage output. To make sure the safety of the equipment that would be tested and the staff of testing, the protest circuit will reach more demanding. This paper make more use of the fast-cahinet’s fast closing character in this kind of variable frequency source. In this circuit, we use many kinds of negative feedback to modify the output wave, which can decrease the distortion. And we use the high-voltage and high frequency capacitance efficiency, which can decrease the disturbance of output signal of variable frequency source for the test of part discharge. In this paper, we resolve the question of high temperature when these high power transistor, and put forward that improving disseminate path and increasing interface area for disseminate will be achieved.After research the variable frequency source successfully, we have research and exploit the technology of computer monitor for this variable frequency source. This progress increases safety and automatization for this equipment when it run in electrical system. Using computer monitor can not only control far away from the site but also operate easily.The variable frequency source have been used on the site for many times, which can resolve much question when test the high equipment. It is prove that this variable frequency source has much character: high reliability, efficiency safety, enough practicability. This equipment can make good society and economy benefit.更多还原