设计模式在继电器特性曲线类库开发中的应用

微机型继电保护利用软件技术实现特性曲线,脱离了传统保护实现上的很多束缚,从而可以设计出更为复杂、更为灵活、更能满足保护四统一要求的动作特性曲线。然而,这也为开发通用化的继电保护测试软件带来了很大的困难。因此,封装优良、复用性好且可扩展性强的继电器特性曲线类库对于继电保护测试软件的开发有重要意义。设计模式就是面向对象软件的设计经验的总结,可以直接用于指导各种面向对象软件的设计。针对继电器特性曲线类库开发中遇到的问题,提出由Facade和Strategy模式相结合的解决方案。该类库已经成功应用于继电保护测试软件中。     

基于模块的可编程保护装置软件设计新概念

指出了采用新的软件设计方法设计微机保护装置的必要性和可行性。采用面向对象的设计思想，借鉴可编程控制器的控制方法，提出了基于模块的可编程可配置的保护软件设计方法。这种方法创造性地将保护装置的动作逻辑与程序进行了分离，使得保护具有最大的灵活性。实践证明这种设计方法非常有效地降低了开发工作量和维护工作量。     

Using TACS functions within EMTP to teach protective relayingfundamentals

The purpose of this discussion is to provide an educational tool for investigating relaying concepts by modeling digital relays using TACS functions within EMTP in a closed-loop manner. Various elements of digital protection systems are identified and organized to generate an systematic approach to modeling the actual hardware of relay systems. Discussion is limited to conventional relaying systems that monitor the vitality of the 60 fit voltages and/or currents. TACS functions for transport delay and pulse generators are used to model dynamics associated with analog to digital conversion and sampling systems. DSP algorithms convert a sequence of sampled data into a sequence of values for magnitude and phase components. A simple example of a time overcurrent relay is developed to demonstrate the techniques to implement relay control in EMTP with TACS and illustrates the kinds of phenomena that can be studied using these techniques     

固态继电器CAD的三维参数化造型和数据库管理系统设计

介绍以AutoCAD 2000为开发平台,以Object ARX、Visual C 6.0为开发工具建立的固态继电器CAD的三维参数化造型和数据库管理系统.使用该系统,用户可以通过输入参数或读取数据库中存储的参数迅速创建固态继电器基本零件的三维实体模型,实现了从数据到图纸的计算机参数化绘图.通过数据库,不仅能管理参数数据,还实现了对固态继电器各种零件的管理.     

面向对象的微机保护测控软件开发与应用

描述了面向对象技术在微机保护测控软件设计中的开发与应用.与传统的基于模块的汇编语言软件设计方法相比,该方法提高了程序的可读性和可维护性,使保护软件具有更大的灵活性.该方法已用于低压变电站众多的非标准软件设计中,能减轻软件开发工作量和维护工作量,提高工作效率.     

Impact of Waveform Distorting Fault Current Limiters on Previously Installed Overcurrent Relays

This paper investigates in detail the impacts of distorted current waveforms, produced by certain types of fault current limiters on time-overcurrent protection relays. A thyristor-based solid-state fault current limiter is chosen as representative of such a device for a case study which investigates its effects on two coordinated protection relays. A detailed software model of the current limiter has been developed and implemented on the real-time digital simulator platform, modeling a typical distribution system. Relay models are used to obtain initial results, which are later validated by an actual protective relay connected in a hardware-in-the-loop simulation setup. The results illustrate the increase of relay tripping times due to severe current limitation caused by the fixed firing angle control of the current limiter. It is revealed that different current measurement principles employed by the relays, such as fundamental, peak, or true rms, can lead to miscoordination due to the distorted fault current waveform. It is demonstrated that these undesirable effects can be mitigated by employing appropriate control strategies for the firing angle in the current limiter.     

Simulation of protective relay performance under short-circuit andtransient swing conditions

Most methods of relay coordination are based on fixed values of fault current for setting protective relays, regardless of the fact that fault currents are time-dependent. The results of alternative transient calculation procedures are presented. These take into consideration the decay of current with time and can therefore be used to identify the sensitivity of the coordination setting and potential cases of difficulty. Comparison of the static and dynamic short-circuit calculation procedures shows that the dynamic procedure, with enhanced machine modeling, produces results that agree well with national standards and minimizes the engineering design effort, with only a small increase in computational overhead. The results presented are used to compare calculated time overcurrent relay settings and tripping times, based on the dynamic short-circuit calculation, with fault clearing times obtained by modeling the relays using a traditional step-by-step dynamic analysis procedure. These two methods of calculation yield results that are in close agreement. It is also shown that inclusion of protection setting and transient modeling facilities in power system CAD packages offers the opportunity to include automatically and reliably the effect of the protection in any subsequent transient studies of the system     

面向对象的微机继电保护测控软件开发方法

指出面向对象方法在低压微机继电保护测控软件设计中的必要性和可行性。与传统的基于模块的汇编语言设计方法相比,该面向对象技术提高了软件的可读性和可维护性,使保护软件具有更大的灵活性。该方法已用于低压变电站众多的非标软件设计中,能减轻软件开发工作量和维护工作量,提高工作效率。     

微机继电保护软件可靠性探讨

微机保护的软件的性能是否可靠,是影响微机保护运行可靠性的关键因素之一。在微机保护开发的整个过程中,应该强调软件的可靠性。简要介绍了衡量软件可靠性的几个要素,指出当前微机保护开发人员对软件可靠性认识的误区,提出一种微机保护软件开发的标准流程。文章强调,应该在开发流程上和开发制度上保证微机保护装置软件的可靠性。     

基于ANSYS对磁保持继电器电磁系统的计算

利用ANSYS软件对旋转式磁保持继电器进行建模及网格划分,对磁保持继电器电磁系统的静态特性进行了仿真,计算出了静态的电磁力矩和磁链,绘制出力矩特性曲线,得出磁通密度矢量图。该仿真方法快速准确地验证了继电器电磁系统的合理性,为继电器的优化设计提供了有效手段。     

Real-time assessment of a symmetrical component and microcontroller based distance relay

This paper presents the design, implementation and real-time assessment of a microcontroller based digital distance relay that can be used for the protection of power transmission lines. The proposed design is implemented using a general-purpose Intel 8097 microcontroller and custom-made filters, operational amplifiers, sample-and-hold amplifiers, multiplexers, and analog-to-digital converters. The relay software is based on a computationally efficient symmetrical component based fault distance estimation algorithm. Results of the performance assessment studies on this algorithm have shown promising fault distance estimates for first-zone faults on the protected transmission line. Real-time implementation of the symmetrical component based fault distance estimation algorithm is presented and discussed in this paper. Hardware and software tools were used to design and fabricate a microcontroller based distance relay using the above-mentioned algorithm. This paper describes details of the design of the distance relay. A test setup in the laboratory using a transmission line model was used to generate data to assess the real-time response of the designed relay. High-speed relay operation of the order of one cycle is demonstrated in the test results.     

继电保护装置自动测试系统设计

分析了继电保护装置自动测试的现状和优势,针对继电保护装置研发过程中性能测试的要求和特点,介绍了一种通用的继电保护装置自动测试系统。该系统采用分布式体系结构和模块化设计思想,利用Python语言构造实时测试脚本,可实现保护装置的闭环自动测试和回归测试。通过改变配置,可以实现对常规站保护装置和数字化站保护装置的自动测试。对自动测试系统各模块的设计进行了详细说明,重点介绍了测试用例的实现方法。实际应用表明,该系统可提高研发过程中的测试质量及效率。     

基于IEC61850标准开发数字变电站可编程的IED

DSI-5000系列微机保护装置是为满足数字化变电的整体要求而策划设计的,采用通用的软硬件平台主要介绍了平台的软硬件特点,比较了采用单CPU和多CPU方案实现IEC61850通讯协议的优缺点,给出了可编程模块的建模实例和实现方法。阐述了在VxWorks操作系统下任务优先级、中断优先级的分配方法以及任务调度机制。介绍了IEC61850 通讯规约的实现过程。     

新一代微机继电保护测试仪及其基本性能

为微机型继电保护装置和安全自动装置测试的需要，以M2000为例，详细介绍了基于DSP、大功率开关放大器和PC机研制而成的新一代微机型继电保护测试仪，介绍了它的基本性能，描述了该仿真器软、硬件的实现，以及仿真器的功能，如电力系统实时仿真、谐波发生器、故障波形成回放、系统振荡模拟、各种类型的继电器测试。该测试仪体积小、重量轻、操作方便，可广泛适用于继电保护生产厂家、实验室、电厂、变电站等场所测试各类继电保护装置。     

Stochastic analysis of fault-induced transients for distance relaying application

It is well known that the operation of distance relays relies on the power frequency components to calculate the fault impedance and hence make decision on tripping. It is also discovered that the transient induced during fault has a significant effect on the performance of distance protection, especially on that of the high-speed protection. A better understanding on fault transient can lead to a better relay design and better performance in terms of speed and relay reach. This paper analyzes the fault transients in EHV transmission lines by using time-domain stochastic techniques. Major emphasis are placed in the investigation into the differences between the fault transient attributes of different fault types and the transient features of the composite signals used in distance relay, such as the phase-to-phase quantities. This investigation leads to the development of adaptive approaches that can be implemented in digital distance relays in order to achieve an improved relay performance.     

动力学参数化可视化仿真软件研究与设计

为解决诸如导弹、多管火箭、火炮等武器系统在方案设计、优化迭代过程中缺少专用的针对动力学参数化仿真软件的问题,研究了多体系统动力学参数化软件理论与技术,开发了多体系统动力学参数化仿真与分析软件.软件集参数化建模、求解、结果可视化功能于一体,通过融合CAD建模方法和多体系统动力学理论,解决了CAD和CAE双向参数驱动,实现了几何模型和动力学模型设计参数无缝传递,为机械系统设计过程中的方案论证、模型优化、方案调整、试验规划、故障诊断等各个阶段提供了一种高精度仿真和方案快速优化设计的手段和数字化工具.     

Multifunction digital relay commissioning and maintenance testing

This paper discusses with the protective relay technology over the past 25 years has evolved from single-function electromechanical (EM) relays, to static (electronic) relays, and, finally, to digital multifunction relays. A significant number of these multifunction digital relays are being installed on medium-voltage electric power systems within industrial and commercial facilities. As was required in earlier EM and static relay technologies, digital relays also require commissioning and relay-setting verification. This article discusses the unique challenges the user faces in testing and commissioning digital multifunction relays. It also explores the impact on maintenance testing of self-diagnostics, the digital relay's internal capability to check itself for failures.     

Field-Programmable Analog Array Based Distance Relay

Protective relays have been designed with different technologies resulting in electromechanical, solid-state, and numerical devices. Speed and reliability are the two most important characteristics of a protective relay. Other capabilities such as monitoring and recording are supposed to be of secondary priority. Without any doubt, present-day numerical relays provide considerable capabilities and advantages but they have not improved speed of operation in comparison to their solid-state counterparts. With advancements in analog technology which has become more mature recently, the idea of using mixed signals in several applications has started. The new technology using combination of field-programmable analog arrays (FPAAs) and digital technologies seems to be a breakthrough and has the potential to provide better performance than the present-day numerical relays. In this paper, use of FPAAs for designing and implementing protective relays is investigated for the first time in literature. A distance relay design and its hardware implementation using FPAAs is described. Test results are reported.      

Investigating the Option of Removing the Antialiasing Filter From Digital Relays

Digital relays traditionally employ sampling rates of less than 100 samples/cycle. In order to avoid aliasing due to fault transients, these relays employ an analog antialiasing filter before critical-sampling (Nyquist rate) the input waveforms coming from instrument transformers. In many applications of electrical engineering, oversampling (greater than the Nyquist rate) has long been used to simplify the requirements of an antialiasing filter with a sharp cutoff; in some cases, the filter can even be eliminated. This paper investigates this option for a digital relay. The performance of a traditional digital relay is compared with a method that uses oversampling without using an antialiasing filter. By processing a comprehensive array of fault waveforms from Electromagnetic Transients Program simulations, a suitable oversampling rate is suggested. A comparison of phasor estimates using the traditional relay and the proposed method is made for different operating and fault conditions. The results suggest that oversampling can eliminate the antialiasing filter traditionally employed in digital relays.     

Real time digital power system simulator design considerations andrelay performance evaluation

Environmental pressures, right of way problems for new transmission lines, large scale system interconnection and increasing power demand especially in developing countries call for new transmission technologies. Use of FACTS and HVDC is gaining momentum. Relaying problems in such systems require a sophisticated approach and numerical technology using high grade processors offers a promising solution. To establish the performance of such relays which are designed more as powerful schemes rather than as a conglomeration of individual relays, detailed testing is required using an elaborate real-time simulator model. These tests are not only necessary during design and development but also are required by the utilities as a part of their acceptance. Highlighting the requirements of a hybrid real-time simulator including the complete spectrum of power system dynamics, this report describes an analog cum digital model used for real-time assessment of system performance. SVCs, HVDC, ASC and CSC can be modelled fully digitally by computer simulation and transient real-time data injection as well as by an analog method using physical simulation with original converter controllers for performance evaluation of numerical relays under real system conditions. As an example of the use of this simulator, tests on a numerical EHV-line relay are described and the relay performance is analyzed