【作者】 朱林；

【导师】 段献忠；

【作者基本信息】 华中科技大学 ， 电力系统及其自动化， 2010， 博士

【摘要】 随着以太网技术的快速发展,以及IEC 61850标准的颁布与实施,以过程层数字化为主要特征的新一代数字化变电站成为目前研究的热点问题。如能将变电站的各种设备连接在同一网络中,实现信息的综合传输,不仅可以简化变电站的体系结构,进一步提高信息共享程度和系统的灵活性、可扩展性,也为各种新功能和新应用的开发提供了更为广阔的空间。鉴于此,本文以基于实时以太网的数字化变电站体系结构和新型应用为研究对象,涉及变电站体系结构设计、IED(Intelligent Electronic Device,智能电子设备)软件设计、继电保护测试、继电保护容错和继电保护动态冗余等内容。以实际的220kV和500kV变电站为例,遵循“星型级联”的思想,对基于过程总线的数字化变电站过程层体系结构进行了设计,应用目的地址标识和虚拟局域网标识的方法实现了SAV(Sampled Analog Value)、GOOSE(Generic Object Oriented Substation Event)报文的多播通信。OPNET仿真结果表明,合理地选择网络带宽和交换机性能参数,并按照优先级标签对信息传输顺序进行调度,过程总线通信方式可满足SAV、GOOSE报文的实时性要求。此外,基于目的地址标识和虚拟局域网标识的多播通信方式可有效地降低网络负载。建立了数字化变电站信息流量模型,在分析流量特性的基础上,提出了基于漏桶模型的流量控制方法,并按信息类别设计了IED和交换机内的漏桶模型参数。仿真分析表明,该方法可以将突发性流量整形成稳定、低速的网络流量,从而有效地抑制网络突发流量和以太网广播风暴,避免交换机缓冲区溢出引起的报文丢失。基于组件技术的IED软件设计方法具有模块化、易维护和可重构等优点,但应用组件技术的关键是定义各种标准组件的模型。分析了单独利用IEC 61850模型或IEC 61499模型定义标准组件的不足,利用IEC 61499模型中的功能块思想对IEC 61850信息模型进行了扩展,建立了综合IEC 61850和IEC 61499的IED组件模型。该模型在保留IEC 61850信息模型的基础上,可对与功能相关的数据、核心算法和执行控制逻辑等进行充分的描述。随后,阐述了利用组件技术设计和开发IED的主要流程,并以简化的线路保护IED为例,在Matlab中验证了所建组件模型的正确性和应用组件技术的主要优势。信息综合传输在简化设备接口的同时,也将简化继电保护测试系统。提出了一种基于PC机的数字化变电站继电保护测试方法。测试所需的暂态数据来自ATP/EMTP的离线仿真,利用数据链路层访问工具WinPcap,经PC机网口向保护装置发送测试所需的SAV和GOOSE报文。采用离线批量仿真和数据在线匹配的方法,实现断路器开断的实时模拟和继电保护的暂态闭环测试。实验结果表明,该方法能满足信息综合传输的数字化变电站继电保护的测试要求,可用普通PC机取代专用的继电保护测试仪器。针对虚假故障数据引起的继电保护误动问题,提出了基于采样值信息融合和保护启动信息融合的两种数字化变电站继电保护容错方法。方法一利用证据理论对冗余采样值数据进行信息融合,判断系统是否存在真实故障,并为继电保护动作提供辅助信息。仿真分析表明,该方法可有效地防止虚假故障数据引起的继电保护误动,通过比较证据的可信度可对虚假故障数据进行辨识。针对方法一的不足,方法二采用表决机制对多个保护装置的启动信息进行融合,可加快判断电力系统状态的速度。从通信系统和软件结构等方面分析了数字化变电站IED的可重构性,提出了利用IED在线重构实现继电保护动态冗余的方法和具体流程,并对其应用前景和不足进行了探讨。该方法能以较低的成本提高数字化变电站内各类保护的可靠性,在中低压系统中具有一定的实用价值。220kV及以上电压等级系统仍应遵循目前的双重化配置原则,但可应用该方法保证一次设备始终配置双重化保护,进一步提高继电保护可靠性。更多还原

【Abstract】 With the rapid development of Ethernet and the advent of the IEC 61850 standard, the new generation of digital substations characterized by digital process level has drawn high attention in recent years. If all the substation devices are connected with one unified communication network and the information is exchanged in the same network, the substation architecture can be greatly simplified to enhance the flexibility and scalability. Moreover, on the basis of open architecture and information sharing, a lot of new functions and applications will be developed to improve the performance of substation automation system. Therefore, the architecture and several new applications in digital substation based on real-time Ethernet are chosen to be the research topics of the thesis, including substation architecture design, Intelligent Electronic Device (IED) software system design, protective relay testing, protective relay fault-tolerance, and dynamic redundancy of protective relay. The outputs of the thesis are listed as follows.Taking practical 220kV and 500kV substation as examples, the process level architectures are designed using cascade star topology. Destination address identification and Virtual Local Area Network (VLAN) identification are used to multicast Sampled Analog Value (SAV) messages and Generic Object Oriented Substation Event (GOOSE) messages. Simulation results in OPNET show that the process bus is suitable to transmit SAV and GOOSE messages in the shared network if the network bandwidth and switch capability are sufficient and the different messages are scheduled according to priority tap. Furthermore, the multicast communication is capable to reduce the network load.On the basis of modeling the information traffic and analysis of traffic characteristic, a traffic control approach based on Leaky Bucket is proposed. The parameters of the Leaky Bucket in IEDs and switches are discussed. Simulations show that the burst traffic can be smoothed to low-speed traffic using the proposed method. Therefore, the burst traffic and broadcast storm can be restrained and the message loss due to buffer overflow of switch can be prevented.The application of generic hardware platforms and component based software technology has the potential to enhance the flexibility of substation IEDs. The component model is proposed to specify various software components with appropriate granularity and provide a framework to integrate them efficiently. The component model is established by extension of IEC 61850 information model using the concept of IEC 61499. The function-related data, detailed function algorithms, and execution logic of the algorithms are contained in the proposed component model, which inherits the IEC 61850 information model. Considerable merits of the proposed IED design approach are also discussed. The prototype system in MATLAB/Simulink demonstrates the feasibility of the proposed component model.The protective relay testing system can be simplified due to the integrative information transmission in the shared network. A transient testing method using a standalone Personal Computer (PC) without commercial test device is proposed. All the test tasks including transient data generation, SAV/GOOSE messages transmission/capture, and performance analysis, are implemented on a standalone PC. Moreover, a WinPcap based communication module residing in the PC is developed to transmit and capture numerous SAV/GOOSE messages instead of multiple Ethernet ports of a commercial test device. Precalculated post-fault current and voltage is utilized to perform a close-loop test to evaluate the reclosure capability. Experiment results demonstrate the effectiveness of the proposed solution for functional test of protective relays.Two fault-tolerant methods are proposed to prevent protective relays from mis-operating in digital substation due to fake measurement: information fusion of sampled value from various Instrument Transformers (IT) and information fusion of start-up signals from various protection IEDs. The former method takes advantage of redundant sampled valve from various ITs to deduce the status of power system and provide supplementary information to protective relay to make a correct decision. Simulations demonstrate the effectiveness of the proposed method. Moreover, the ITs providing fake measurement can also be identified. The later method is an improved one, which utilizes the start-up signals from various protection IEDs to indicate the power system status by means of voting.Finally, after the analysis of reconfigurability of digital substation IED communication and software architecture, the approach of dynamic redundancy of protective relay based on on-line IED reconfiguration is proposed, as well as its procedure. The application prospect and disadvantages of the method are also discussed. The proposed approach is feasible to enhance the reliability of protection system in a cost-efficiency way in low and medium voltage power systems. For high voltage power system, dual configuration of protection system is still recommended. However, the proposed approach can be adopted to ensure the primary equipment is always under protection of dual protective relays to guarantee the reliability.更多还原