变电设备状态信息光纤/光学传感研究

准确感知输变电设备的运行状态,及时采取有效的运维检修策略,对保证新型电力系统安全高效运行意义重大。光纤/光学传感具有绝缘性能好、抗电磁干扰、可分布式测量、测量精度高等优点,在变电设备领域发展迅速。该文介绍了包括基本电气量(电压、电流)、设备状态量(温度、湿度、压力、振动)、绝缘状态量(分解产物、局放)的光纤/光学感知原理与主要研究进展,对比讨论了不同监测方法的优缺点。并在此基础上,重点分析了现有技术尚未攻克的难点问题与发展趋势,期望对新型电力系统全息感知能力的提升提供参考。

基于RFID传感器网络节点低功耗设计研究

针对现有传感器网络节点低功耗设计很难从系统角度提供整体设计方案的问题,提出节点在软硬件方面的设计策略。通过对集成电路和外围电路的研究,提出了可供广泛使用的低功耗布局和设计思想,采用外设按键发送节点身份信息的方法解决节点和位置点间对应关系的问题。在此基础上,通过对通讯模式、发送周期及次数和睡眠模式等软件设计方面的研究,提出适用于不同工程需求的软件低功耗运行策略。最后,设计并实现安全带插拔状态监控的低功耗系统,对此系统进行联调实验,提出系统使用节点的耗电模型并预测其使用时限,最长时限约为4.81年,满足系统对有源RFID节点一次满电的寿命要求。

State Estimation Method for GNSS/INS/Visual Multi-sensor Fusion Based on Factor Graph Optimization for Unmanned System

With the development of unmanned driving technology,intelligent robots and drones,high-precision localization,navigation and state estimation technologies have also made great progress.Traditional global navigation satellite system/inertial navigation system(GNSS/INS)integrated navigation systems can provide high-precision navigation information continuously.However,when this system is applied to indoor or GNSS-denied environments,such as outdoor substations with strong electromagnetic interference and complex dense spaces,it is often unable to obtain high-precision GNSS positioning data.The positioning and orientation errors will diverge and accumulate rapidly,which cannot meet the high-precision localization requirements in large-scale and long-distance navigation scenarios.This paper proposes a method of high-precision state estimation with fusion of GNSS/INS/Vision using a nonlinear optimizer factor graph optimization as the basis for multi-source optimization.Through the collected experimental data and simulation results,this system shows good performance in the indoor environment and the environment with partial GNSS signal loss.

基于PDI的机电设备无线传感监控质量评估验证方法

评估验证高功率密度电机、风电及轨道交通等机电设备的监控质量,保障机电系统的安全、绿色运行,对于推动国家绿色制造战略实施意义重大。然而,现有针对物联网监测系统的完整性验证评估方法,仅评估了系统监测设备和集成终端的完整性,忽视了传感监控数据采集与汇聚过程中的安全威胁;再者,现有技术对监控系统评估和验证仅在项目验收或者出现问题时进行,缺乏有针对性的长效策略。对此,本文从监控系统的安全性与高效性出发,提出了一种基于完整性动态验证算法(PDI)的机电设备传感数据监控质量评估验证方法。PDI算法通过数据扰动对数据的隐私加以保护,通过动态生成对应网络结构的检测节点对数据进行完整性验证,提升了融合过程中检测并丢弃篡改过的虚假数据的效率。

Double ESOs-based field-oriented control for PMSM drive system with current sensorless

A novel double extended state observers(ESOs)-based field-oriented control(FOC)strategy is developed for three-phase permanent magnet synchronous motor(PMSM)drive systems without any phase current sensor.In principle,two current sensors are essential parts of the drive system for implementation of the feedback to achieve high accuracy control.For this purpose,the double ESOs are created to provide feedback stator currents instead of actual current sensors.The first one of the double ESOs is designed to estimate the benchmark value of q-axis stator current,which is a primary premise;While the second is designed to estimate real-time stator currents of d-axis and q-axis simultaneously.The resultant double ESOs can rapidly and accurately give estimation of the actual currents of a-axis,b-axis and c-axis,and the synthesized double ESOs-based FOC strategy for PMSM drive system without any current sensors has satisfactory control performance and strong robustness.Numerical experiments validate the feasibility and effectiveness of the proposed scheme.

Fault diagnosis and fault-tolerant control of photovoltaic micro-inverter

An observer-based fault diagnosis method and a fault tolerant control for open-switch fault and current sensor fault are proposed for interleaved flyback converters of a micro-inverter system. First, based on the topology of a grid-connected micro-inverter, a mathematical model of the flyback converters is established. Second, a state observer is applied to estimate the currents online and generate corresponding residuals. The fault is diagnosed by comparing the residuals with the thresholds. Finally, a fault-tolerant control that consists of a fault-tolerant topology for the faulty switch and a simple software redundancy control for the faulty current sensor, is proposed to achieve a fault-tolerant operation. The feasibility and effectiveness of the proposed method has been verified by simulation and experimental results.

An Experience of On-site PD Testing for Condition Monitoring of an 11 kV PILC Cable Insulation System

A cable circuit of a substation in the United Kingdom showed high level of PD activities during a survey using hand hold PD testing equipment. The authors were invited to carry out on-site PD testing experiment to further diagnose and locate the potential problem of the cable system. This paper presents the experience of the present authors carrying out the cable test. Following a brief introduction to the experiment equipments and physical connections, the paper analyses the data collected from the testing, including PD pulse shape analysis, frequency spectrum analysis and phase resolved PD pattern analysis. Associated with PD propagation direction identification, PD source diagnosis and localisation was made. Four different types of sensors, which were adapted during the testing, are shown to have different frequency bandwidths and performed differently. Aider comparing the parameters of the sensor and the PD signals detected by individual sensor, optimal PD monitoring bandwidth for cable system is suggested.

Virtual speed sensors based algorithm for expressway traffic state estimation

The accurate estimation of expressway traffic state can provide decision-making for both travelers and traffic managers. The speed is one of the most representative parameter of the traffic state. So the expressway speed spatial distribution can be taken as the expressway traffic state equivalent. In this paper, an algorithm based on virtual speed sensors (VSS) is presented to estimate the expressway traffic state (the speed spatial distribution). To gain the spatial distribution of expressway traffic state, virtual speed sensors are defined between adjacent traffic flow sensors. Then, the speed data extracted from traffic flow sensors in time series are mapped to space series to design virtual speed sensors. Then the speed of virtual speed sensors can be calculated with the weight matrix which is related with the speed of virtual speed sensors and the speed data extracted from traffic flow sensors and the speed data extracted from traffic flow sensors in time series. Finally, the expressway traffic state (the speed spatial distribution) can be gained. The acquisition of average travel speed of the expressway is taken for application of this traffic state estimation algorithm. One typical expressway in Beijing is adopted for the experiment analysis. The results prove that this traffic state estimation approach based on VSS is feasible and can achieve a high accuracy.

Recent advances in the neural regulation of feeding behavior in adult Drosophila

The ability to maintain metabolic homeostasis is a key capability critical for the survival and well-being of animals living in constantly changing environments.Metabolic homeostasis depends on neuromodulators,such as biogenic amines,neuropeptides,and hormones,to signal changes in animals’ internal metabolic status and to orchestrate their behaviors accordingly.An important example is the regulation of feeding behavior by conserved molecular and cellular mechanisms across the animal kingdom.Its relatively simple brain coupled with well-characterized genetics and behavioral paradigms makes the fruit fly Drosophila melanogaster an excellent model for investigating the neuromodulatory regulation of feeding behavior.In this review we discuss the neuromodulators and neural circuits that integrate the internal physiological status with external sensory cues and modulate feeding behavior in adult fruit flies.Studies show that various specific aspects of feeding behavior are subjected to unique neuromodulatory regulation,which permits fruit flies to maintain metabolic homeostasis effectively.

A Real-Time Collision-Free Path Planning of a Rust Removal Robot Using an Improved Neural Network

In this paper, a real-time collision-free path planning of the rust removal robot in a ship environment is proposed, which is based on an improved biologically inspired neural network algorithm. This improved algorithm is based on the biologically inspired neural network and modified with obstacle detection sensors and kinematic state templates, and is implemented in a ship rust removal robot planning system for dynamic trajectory generation. The real-time optimal trajectory is generated by the biologically inspired neural network, and the moving obstacle detection process of a ship robot working on the wall is simulated with the obstacle detection sensors models. The local real-time trajectory can be re-planned by the updated local map information, where the obstacle detection sensors are used to inspect partial environment information and update the robot nearby information in real time in the original neural network algorithm. At the same time, the method of the kinematic state templates matching and searching is used to solve the pipes’ influence of the rust removal robot climbing on the wall, which can not only provide a smooth path, but also can judge the motion direction and turning angle of the robot. Comparison of the proposed approach with the simulation shows that the improved algorithm is capable of planning a real-time collision-free path with achieving the local environmental information and judging the rust removal robot’s motion direction and turning angle. This proposed algorithm can be good used in the ship rust removal robot. © 2017, Shanghai Jiaotong University and Springer-Verlag GmbH Germany.

Application Research on Hydraulic Coke Cutting Monitoring System Based on Optical Fiber Sensing Technology

With the development of the optical fiber sensing technology, the acoustic emission sensor has become one of the focal research topics. On the basis of studying the traditional hydraulic coke cutting monitoring system, the optical fiber acoustic emission sensor has been applied in the hydraulic coke cutting monitoring system for the first time, researching the monitoring signal of the optical fiber acoustic emission sensor in the system. The actual test results show that using the acoustic emission sensor in the hydraulic coke cutting monitoring system can get the real-time and accurate hydraulic coke cutting state and the effective realization of hydraulic coke cutting automatic monitoring in the Wuhan Branch of Sinopec.

Coordinated motion of molecular motors on DNA chains with branch topology

To understand the macroscopic mechanical behaviors of responsive DNA hydrogels integrated with DNA motors,we constructed a state map for the translocation process of a single FtsKc on a single DNA chain at the molecular level and then investigated the movement of single or multiple FtsKc motors on DNA chains with varied branch topologies.Our studies indicate that multiple.FtsKc motors can have coordinated motion,which is mainly due to the force-responsive behavior of individual FtsKc motors.We further suggest the potential application of motors of FtsKc,together with DNA chains of specific branch topology,to serve as strain sensors in hydrogels.