SIA OpenIR  > 工业控制网络与系统研究室
Alternative TitleResearch on Time Synchronization for Wireless Recording System in Transformer Substation
Thesis Advisor尚志军
Keyword无线录波系统 时间同步 概率同步 贝叶斯估计
Call NumberTN926/L77/2015
Degree Discipline控制工程
Degree Name硕士
Degree Grantor中国科学院沈阳自动化研究所
Place of Conferral沈阳
Abstract为保证输变电设备的可靠运行,电力公司状态评价中心在高电压等级变电站投运之前,需要完成站内重要设备的启动调试试验。在启动调试试验中,录波系统通过电流互感器和电压互感器测量瞬态信号。传统的录波系统需要在不同位置的电流、电压采集点布设临时线缆,工作量大并且伴随安全风险。将无线通信技术应用于录波系统可以提高启动调试试验的效率和安全性。但是,无线录波系统必须解决不同采集节点的时间同步问题。 论文针对无线录波系统的特点,设计了两种可用于无线录波系统的时间同步方法,并搭建了无线通信网络实验平台,在该平台上验证了两种方法的有效性。论文的主要工作及成果如下: 1. 总结了无线录波系统对时间同步的应用需求,对比无线传感器网络时间同步相关研究,分析无线录波系统时间同步问题的技术挑战。 2. 设计了一种低开销的概率时间同步方法。根据概率统计理论,该方法得出同步参数(同步周期、同步信息个数)与同步精度、失效概率的关系,根据需求设置不同的同步参数,通过补偿时钟偏差确保节点在一定概率下的时间同步精度。此外,本方法由监控中心集中维护各节点的时间关系,减少了同步信息的发送开销。 3. 设计了一种基于贝叶斯估计的时间同步方法。基于贝叶斯估计原理,该方法可以估计出同步信息传输延迟中接收时间的不确定性,从而估算出更准确的同步信息接收时间,提高时间同步精度。此外,本方法通过两次广播实现采集节点间的时间同步,通过同时补偿时钟偏差和时钟漂移,延长了同步周期,减少了同步信息的发送开销。 4. 搭建了无线录波系统的通信网络实验平台,设计了相应的时间同步测试方案,在该平台上完成了两种同步方法的同步精度测试。
Other AbstractGenerally, the status assessment center in every power company needs to conduct start-up and commissioning tests before putting the high-voltage substation into operation, with the purpose of ensuring the transmission and distribution equipment’s reliable performance. At the same time, the transient signals captured by current and voltage transformers are collected in the recording system. However, traditional recording systems require temporary cables to be set up on different sites so as to collect current and voltage,which leads to heavy workload and high security risks. Therefore, the application of the wireless communication technology into the recording system has improved the efficiency and safety of the start-up and commissioning tests. And there are still some problems about how to maintain the time synchronization of different collecting sites in the wireless recording system. Considering the features of the wireless recording system, the present study has suggested two ways to solve the synchronizing problem in the wireless recording system. Furthermore, an experimental platform for the wireless communication network has been built to testify the validity of the above methods. The main work and achievements in the present study are listed as follows: 1. The requirements of wireless recording system for time synchronization, and the technical challenges of time synchronization in the wireless recording system are summarized after the relevant literatures are review. 2. A probabilistic time synchronization method with low overhead is designed. According to probability and statistics theory, the method is able to obtain the relationship between the synchronization parameters (the synchronization period, the amount of the synchronization information in each period), the synchronization accuracy and the risk probability. Thus, setting different synchronization parameters based on the requirements,the time synchronization accuracy of each node under a certain probability can be ensured by compensating the clock offset. In addition, the method reduces the workload of information exchange thanks to the centralized maintenance of the time relationship among different sites by the monitoring center. 3. Another time synchronization method is designed based on the Bayesian estimation. The method is capable of estimating the uncertainty of reception time in transmission delay in accordance with the Bayesian estimation principle. Therefore, a more accurate reception time is likely to be achieved to improve the synchronization accuracy. Moreover, the method extends the synchronization period and reduces the workload in information exchange by two broadcasts in the synchronization process and the compensation of both clock skew and clock offset. 4. An experimental platform for the communications network in the wireless recording system is built, and the corresponding test program of time synchronization is designed. The synchronization accuracy of the two methods mentioned above is tested on the platform, respectively.
Contribution Rank1
Document Type学位论文
Recommended Citation
GB/T 7714
柳正青. 面向变电站无线录波系统的时间同步方法研究[D]. 沈阳. 中国科学院沈阳自动化研究所,2015.
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