基于RTDS的厂用电源切换研究

发布时间：2018-11-25 07:20

【摘要】：对于电厂和大型用电企业,厂用电的可靠性在安全生产中起着至关重要的作用。厂用电的快速切换是提高其可靠性的主要方式之一,即通过安全自动装置将负荷快速切换至其他备用电源。随着快切装置的不断改进,尤其是同期捕捉切换方式的提出,大大提高了厂用电切换成功率,减少了切换所需时间。然而随着自备电厂的兴起,为了降低成本,开始尝试采用自备电厂孤网运行方式。在这个过程中,厂用电切换方式发生了根本的改变。为厂用母线供电的两个电源“厂用变压器”和“启动备用变压器”,是相对独立的两个电源,与传统的切换方式相比,两个独立电源之间的切换可能会导致厂用电母线非同期短路;或是因相角差过大,装置切换闭锁或是切换时间过长,导致厂用电失电的情况发生。本文对机组厂用电切换方式及切换的动态过程进行仿真,深入研究厂用电切换对孤网运行机组的影响并提出运行建议。主要工作如下:1、研究感应电动机数学模型,同时利用实时数字仿真仪(RTDS)中的感应电动机模型搭建300MW级机组的厂用电系统。采用已运行机组的厂用电切换数据以及感应电机启动数据对所搭建模型进行优化,提高模型与实际电机运行状态的相似度。2、利用已建立的仿真模型,对孤网运行下的机组在两个相对独立电源之间的切换过程进行仿真研究。模拟在频率、初相角不同时两个电源的切换过程,了解不同运行工况对不同类型的厂用负荷的影响。3、通过分析孤网下发电机组厂用电切换数据,发现现有厂用电切换系统可能存在的问题及隐患,并提出一种具备自动调节能力的厂用电切换方式。
[Abstract]:For power plants and large power enterprises, the reliability of auxiliary power plays a vital role in production safety. One of the main ways to improve the reliability of power supply is to quickly switch the load to other power supply by means of safety automatic device. With the continuous improvement of the fast cutting device, especially the simultaneous capture switching mode, the success rate of power supply switching is greatly increased, and the switching time is reduced. However, with the rise of the self-provided power plant, in order to reduce the cost, it began to try to use the isolated network operation mode of the self-provided power plant. In this process, the mode of power switching has been fundamentally changed. Two power sources, "Factory Transformer" and "start standby Transformer", are two independent power sources, compared with the traditional switching mode. Switching between two independent power sources may lead to a non-synchronous short-circuit of the auxiliary bus; Or because the phase angle difference is too big, the device switch locking or switching time is too long, resulting in the situation of power loss. This paper simulates the mode and dynamic process of switchover, studies the influence of switchover on the unit and puts forward some suggestions. The main work is as follows: 1. The mathematical model of induction motor is studied and the auxiliary power system of 300MW unit is built by using the induction motor model in the real-time digital simulator (RTDS). In order to improve the similarity between the model and the actual motor running state, the model is optimized by using the switchover data of the running unit and the induction motor starting data, and the established simulation model is used to improve the similarity between the model and the running state of the actual motor. The switching process between two relatively independent power sources is simulated. This paper simulates the switching process of two power sources at different frequency and initial phase angle to understand the influence of different operating conditions on different types of auxiliary load. The possible problems and hidden dangers of the existing switchover system are found, and a switching mode with the ability of automatic regulation is proposed.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM762.1

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