三相点

In the paper, double loop control is also discussed simply.

并简述了电压电流双环控制在三相逆变器上实现的注意点。

It is extensively used for different occasions that require DC power supply, including electrolytic chemistry, transmission, traction, electrostatic precipitation, electroplating and DC transmission etc.

整流变压器是指把电力网的三相正弦交流电压变换为所需要的交流整流电源的电压和相数的电源变压器，它广泛应用于点解化学、传动、牵引、静电除尘、电镀、直流输电等需要提供直流电源的场合。

The characteristic of primary arc is analyzed, and the dynamic model of primary arc is established. The line differential equation including primary arc voltage is constructed, and the parameter estimation technique is used to estimate the voltage amplitude of primary arc, so as to determine the fault type and realize adaptive three-pole-autoreclosure.

分析了一次电弧的特点，建立了一次电弧的动态模型，利用一次电弧的特点建立了包含电弧电压的超高压输电线路相间短路的线路微分方程，通过参数估计的方法求得故障点的电弧电压，以判断故障类型，实现自适应三相重合闸。

By systemic researching and simulating experiment, the text gains such results as follows,1. On the base of sufficiency research on the oil-gas hydrocarbon systemic chemistry composing and the physical chemistry characters, we traverse the mechanism of the paraffin's deposition. Then we consider that paraffin deposition is a complex process ofphysical chemistry, which includes more than one single mechanism.2. Traversing and comparing the literature in detail on different factors that has effect on paraffin deposition, the available experimental methods on paraffin deposition, prevention of paraffin deposition, and removing of the deposited paraffin on the spot.3. Ameliorated the laser equipment of solid particle inspecting system and the corresponding test methods. Determine WCT of dead oil and live oil from KS101 well under different pressure with this system. The result implies that dead oil has opposite regulation on paraffin deposition temperature to live oil.4. A vapor-liquid-solid envelop is drawn by superposition regular vapor-liquid envelop and WCT curve thereby explained that the departure and quick raising of the curve in the low temperature zone is caused by the appearance of paraffin in solid phase.5. Estimation is made to determine the depth of paraffin deposition in the well.

通过系统的研究和实验模拟，本文取得了以下研究成果：(1)在充分调研油气烃类体系的化学组成及其物理化学特征的基础上，详细研究了石蜡沉降的机理，认为石蜡沉积是一个复杂的物理化学过程，是多种机理共同作用的结果；(2)深入调研并综合阐述了影响石蜡固相沉积的各种主要因素，对目前国内外常用的有机固相沉积实验研究方法和现场清防蜡措施也做出详尽的描述，并加以对比评价；(3)改进了油气藏开发重点实验室自行研制组装的高温高压下测定固相沉积的激光装置和测试方法，并用该套设备测定出柯深101井的井口脱气油样和凝析气平衡油样不同压力下的析蜡点，实验结果表明，脱气油和平衡油析蜡规律相反；(4)将常规气-液两相相图和析蜡曲线叠加得到了气—液—固三相相图，从而解释了气-液两相等液量线在低温区域偏离正常并快速上翘是由于体系有石蜡固相出现；(5)利用实验测试的析蜡温度预测析蜡位置，表明只有在距井口465m油管以上会有蜡析出。

The research work of this paper is divided into five parts: The first ,according to the work characteristics of ship's auxiliary boiler, this paper is to design applied project in the automatic control system of ship's auxiliary boiler; The second, according to the work request of the cargo winch of alternating three-speed change-pole speed-adjusting, this paper is to determine adopting the method of the PLC control; The third, this paper is to design PLC application in three -phase induction motor control, to give the ladder chart, program and input and output circuit diagram; The fourth, this paper is to research the method of the ship's combined starting screen automatic control with the PLC; The fifth, this paper is to inquire the possibility of apply the PLC in ship's engine room surveillance system; According to the comprehensive analysis of above actual example of ship's auxiliary machinery automatic system with the technique of PLC; not only can use the technique of PLC to replace traditional relay-contactor control technique in ship's auxiliary machinery automatic system, but also can get the conclusion of the former is more dependable and more clever than the latter, the maintenance is more convenient, thus develop a new path for ship automation.

本文研究的工作主要包括五个部分：第一，根据船舶辅锅炉的工作特点，设计PLC在船舶辅锅炉自动控制系统中的应用方案，主要有PLC选型及输入输出点的设计，画出系统控制梯形图并分析工作原理；第二，根据交流三速变极调速起货机的工作要求，确定采用PLC控制的方法，进行控制系统的硬件设计和软件设计，并分析工作原理：第三，设计了PLC在三相异步电动机控制中的应用，给出了控制梯形图、程序及输入、输出接线图；第四，研究了用PLC实现船舶组合起动屏自动控制的方法，进行了系统的电源设计和软件设计，给出系统工作流程图；第五，探讨了船舶机舱监视系统应用PLC的可行性，将继电器报警线路改为用PLC控制报警，给出系统硬件图和软件梯形图，并分析了PLC机的选型、抗干扰和应用PLC的经济效益和社会效益等问题。综合以上船舶辅助机械自动控制系统采用PLC技术的实例分析，可以得出船舶辅助机械自动控制系统不但可以使用PLC技术取代传统的继电器接触器控制技术，而且前者比后者更可靠、更小巧，维护保养更方便的结论，从而为船舶自动化开辟了一条新的路径。无忧毕业设计网 www.5ubs.cn

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Introduced the analysis and processing of a transformer with three-phase winding of DC resistance imbalanced defect,through further analysis of the after processed DC resistance,believed the transformer still existing the polarity selector"-" side contact deficiency,further on finding out the method of comparing corresponding DC resistance difference rate at each tap has the advantage to detect the polarity selector defect more accurately more sensitively and more directly.

对一台变压器出现三相绕组直流电阻不平衡缺陷的分析和处理情况做了介绍；通过对处理后直流电阻的进一步分析认为，该变压器还存在极性选择开关&－&向侧仍有接触不良方面的缺陷，遂进一步提出，如采用比较各对应分接位置下直流电阻差率的方法能够有更准确、灵敏、直接地发现极性选择器方面缺陷的优点；还提出了测试变压器绕组直流电阻时的几点注意事项。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。