外文翻译

1 Introduction

Power system protection is to ensure the safe operation of power systems, enhance economic efficiency and effective technology. Successfully applied to computer control technology in power system protection, relay protection technology trends make the future a computerized network, intelligence and so on.

Subject of protection, technology, manufacturing and personnel training relay from scratch, living in a small absorption of foreign advanced technology protection equipment and operation, based on the completion of a team with deep theoretical knowledge and rich experience in running Relay team. After 60 years of development and exploration, China has built a protection research, design, manufacturing, operation and maintenance, and teaching the complete system.

2Development Status of relay

60s of last century to the vigorous protection transistor 80 is widely used in the

development and age. One Tianjin University and Nanjing Electric Power Automation Equipment Factory collaborative research direction of 500kV high-frequency transistors, Nanjing Automation Research Institute, protection and development of high-frequency blocking distance protection transistors, running at Gezhouba 500kV line, ending a 500kV line protection totally dependent on imports from abroad era. 70s in the 20th century, based on an integrated operational amplifier integrated circuit protection has begun to study. Protection of the late '80s has formed a complete series of integrated circuits, and gradually replace the transistor protection. IC 90 protection early development, production and application is still in a dominant position, which is integrated circuit protection era. 70 China from the late 20th century, already started the research of computer protection, North China Electric Power University in 1984, developed the original transmission line through the identification of the first microprocessor-based protection devices, and access to applications in the system, opened the development of protection new page in history for the computer opens the way for the promotion of protection. From 90 years of relay protection technology has entered the computer age. Different principles, different types of computer equipment protection circuit and the main distinctive for a new generation power system provides excellent performance, fully functional and reliable relay protection device. With the computer protection device studies in computer protection software, algorithms have also made a lot of theoretical results.

3 Power System Development

3.1 Computerization

According to the famous Moore's Law, chip integration doubling every 18-24 months. The result is not only doubled the performance of computer hardware, prices are rapidly declining. Mainly reflected the development of microprocessor technology and related functions in a single great enhancement, on-chip hardware resources have been greatly expanded, both MCU and DSP chip technology integration significantly increased computing power and network communications chips embedded The emergence and application aspects. These developments make the hardware design is more convenient, cost-effective redundancy design makes it possible to achieve a flexible, high reliability, and modular hardware and software platform to create the conditions for the general.

Of 220kV and above in 2000, microprocessor-based protection system was 43.99%, 86% of microprocessor-based protection circuit to the end of 2003, 220kV or more microprocessor-based protection system has been accounted for 70.29%, of microprocessor rate of 97.6%. Actual operation, the microprocessor-based protection of the right action rate was significantly higher than other protection, generally higher than the average normal operation 0.2-0.3 percentage points.

Computerized relay protection devices is an irreversible trend. Power system protection requirements on the computer increasing, in addition to the protection of basic functions, but also with large-capacity long-term failure information and data storage space, fast data processing capabilities, powerful communications capabilities, and other protection, control and scheduling of networked devices for system-wide data sharing, information and network resource capacity, high-level language programming.

3.2 Network

Network protection is computer technology, communication technology, network technology and the product of the combination of microprocessor-based protection, achieved through a variety of computer network protection features such as line protection, transformer protection, busbar protection. The greatest benefit is the network protection data sharing can be achieved have been protected by the high-frequency, fiber protection can be achieved in the pilot protection. In addition, the substation protection system for all circuit breakers at the station collected the amount of current, bus voltage amount, so it is easy bus protection can be achieved without the need for additional bus protection.

Power system network based protection is a new type of relay protection, computer protection technology is the inevitable trend of development. It is built on computer technology, network technology, communication technology and the development of computer technology on the basis of protection. Network protection systems in the network at the provincial level, provincial municipal and city level backbone network topology, and topology of sub-station system can be simple and reliable bus structure, star structure, ring structure. Substation protection system across the network protection system is the most important aspect. Substation protection system has 2 modes: one is the use of existing microprocessor-based protection; the other is the formation of the new system, various protection functions entirely by the sub-station machine to achieve protection and management system. Because of the importance of relay protection in

power, must take control of a targeted strategy for network security to ensure the network protection system security.

3.3 Intelligent

With the rapid development of computer technology and computer power system protection in the general field of application of new control principles and methods

continue to be used in the computer relay protection in recent years, artificial intelligence technologies such as expert systems, artificial neural network, genetic algorithms, fuzzy logic, wavelet theory in power systems have been applied in various fields, so that the protection of the development to a higher level, there has been notable new trend. For example, the field of power system protection using artificial neural networks occurs (ANN) to determine the type of fault, fault distance determination, direction, protection, master protection. In the transmission line both sides of the potential of a system point of view the case laid out by the transition resistance of the short circuit occurred is a nonlinear problem, the distance protection is difficult to determine the correct position to make trouble, resulting in malfunction or refuse to move; if the neural network method After

training a large number of fault samples, as long as the sample set given full consideration to all the circumstances, it can be in the event of any failure of correct classification.

With the continuous development of artificial intelligence technology, new methods are constantly emerging, in the power system relay protection is also expanding the scope for the development of protection inject new vitality. Artificial intelligence technology will be a different combination of uncertain factors on the protective system, thereby improving the reliability of protection action, the development of the future direction of intelligent

protection. While the above method in Power System Protection Intelligent application yielded some results, but the theory itself is not very mature and need further improvement. With the rapid development of power systems and computers,

communications and other advances in technology and development, can be predicted that the field of artificial intelligence technology in the protection will be applied to solve using conventional methods are difficult to solve.

3.4 Automation

Modern computer technology, communications technology and network technology to change the current substation monitoring, control, protection and measuring devices and systems division provides the optimal combination of state and system integration technology base. High Voltage, EHV substation is facing a technological innovation. Protection and realization of the close combination of integrated automation, which is exhibited in integration and resource sharing, remote control and information sharing. The remote terminal unit (RTU), computer protection device as the core, the substation control, signals, measurement, billing and other loops into the computer system to replace the traditional control of the screen, to reduce footprint and substations equipment investment, improve the reliability of the secondary system.

Integrated automation system to break the traditional boundaries of secondary systems

and equipment for the professional division of the principle of the conventional protection can not be changed and scheduling (control) the defect central communications, to the substation automation has given meaning and content updates, on behalf of the substation The development of a trend of automation technology. With the development of science and technology, more whole, more intelligent level, the system better EHV substation integrated automation system, power grid construction in China will continue to emerge, the network's security, stability and improved economic performance to a new level.

电力系统继电保护概述

1 引言

电力系统继电保护是保证电力系统安全运行、提高经济效益的有效技术。计算机控制技术成功运用到电力系统继电保护中,使得未来继电保护技术发展趋势具有计算机化、网络化、智能化等特点。

我国继电保护学科、技术、继电器制造和人才队伍培养从无到有,在小活吸收国外先进继电保护设备和运行技术的基础上,建成了一支具有深厚理论功底和丰富运行经验的继电保护队伍。经过60年的发展和探索,我国已经建成了继电保护研究、设计、加工制造、运行维护和教学的完整体系。

2 我国继电保护的发展现状

上世纪60年代到80年代是晶体管继电保护蓬勃发展和广泛采用的时代。其中天津大学与南京电力自动化设备厂合作研究的500kV晶体管方向高频保护和南京电力自动化研究院研制的晶体管高频闭锁距离保护,运行于葛洲坝500kV线路上,结束了500kV线路保护完全依靠从国外进口的时代。在20世纪70年代中,基于集成运算放大器的集成电路保护已开始研究。到80年代末集成电路保护已形成完整系列,逐渐取代晶体管保护。到90年代初集成电路保护的研制、生产和应用仍处于主导地位,这是集成电路保护时代。我国从20世纪70年代末即已开始了计算机继电保护的研究,1984年原华北电力学院研制的输电线路微机保护装置首先通过鉴定,并在系统中获得应用,揭开了我国继电保护发展史上新的一页,为微机保护的推广开辟了道路。从90年代开始我国继电保护技术已进入了微机保护的时代。不同原理、不同机型的微机线路和主设备保护各具特色,为电力系统提供了一批新一代性能优良、功能齐全且工作可靠的继电保护装置。随着微机保护装置的研究,在微机保护软件、算法等方面也取得了很多理论成果。

3 电力系统继电保护发展趋势

3.1 计算机化

按照著名的摩尔定律,芯片上的集成度每隔18—24个月翻一番。其结果是不仅计算机硬件的性能成倍增加,价格也在迅速降低。微处理机的发展主要体现在单片化及相关功能的极大增强,片内硬件资源得到很大扩充,单片机与DSP芯片二者技术上的融合,运算能力的显著提高以及嵌入式网络通信芯片的出现及应用等方面。这些发展使硬件设计更加方便,高性价比使冗余设计成为可能,为实现灵活化、高可靠性和模块化的通用软硬件平台创造了条件。 我国在2000年220kV及以上系统的微机保护率为43.99%,线路微机保护占86%,到2003年底,220kV以上系统的微机保护已占到70.29%,线路的微机化率达到97.6%。实际运行中,微机保护的正确动作率要明显高于其他保护,一般比平均正常动作率高0.2—0.3个百分点。 继电保护装置的计算机化是不可逆转的发展趋势。电力系统对微机保护的要求不断提高,除了保护基本功能外,还应具有大容量故障信息和数据的长期存放空间,快速的数据处理功

能,强大的通信功能,与其他保护、控制装置和调度联网以供享全系统数据、信息和网络资源的能力、高级语言编程等。 3.2 网络化

网络保护是计算机技术、通信技术、网络技术和微机保护相结合的产物,通过计算机网络来实现各种保护功能,如线路保护、变压器保护、母线保护等。网络保护的最大好处是数据共享,可实现本来由高频保护、光纤保护才能实现的纵联保护。另外,由于分站保护系统采集了该站所有断路器的电流量、母线电压量,所以很容易就可实现母线保护,而不需要另外的母线保护装置。

电力系统网络型继电保护是一种新型的继电保护,是微机保护技术发展的必然趋势。它建立在计算机技术、网络技术、通信技术以及微机保护技术发展的基础上。网络保护系统中网省级、省市级和市级主干网络拓扑结构,以及分站系统拓扑结构均可采用简单、可靠的总线结构、星形结构、环形结构等。分站保护系统在整个网络保护系统中是最重要的一个环节。分站保护系统有2种模式:一是利用现有微机保护;另一个是组建新系统,各种保护功能完全由分站系统保护管理机实现。由于继电保护在电网中的重要性,必须采取有针对性的网络安全控制策略,以确保网络保护系统的安全。 3.3 智能化

随着计算机技术的飞速发展及计算机在电力系统继电保护领域中的普遍应用,新的控制原理和方法不断被应用于计算机继电保护中,近年来人工智能技术如专家系统、人工神经网络、遗传算法、模糊逻辑、小波理论等在电力系统各个领域都得到了应用,从而使继电保护的研究向更高的层次发展,出现了引人注目的新趋势。例如电力系统继电保护领域内出现了用人工神经网络(ANN)来实现故障类型的判别、故障距离的测定、方向保护、主设备保护等。在输电线两侧系统电势角度摆开情况下发生经过渡电阻的短路就是一非线性问题,距离保护很难正确作出故障位置的判别,从而造成误动或拒动;如果用神经网络方法,经过大量故障样本的训练,只要样本集中充分考虑了各种情况,则在发生任何故障时都可正确判别。

随着人工智能技术的不断发展,新的方法也在不断涌现,在电力系统继电保护中的应用范围也在不断扩大,为继电保护的发展注人了新的活力。将不同的人工智能技术结合在一起,分析不确定因素对保护系统的影响,从而提高保护动作的可靠性,是今后智能保护的发展方向。虽然上述智能方法在电力系统继电保护中应用取得了一些成果,但这些理论本身还不是很成熟,需要进一步完善。随着电力系统的高速发展和计算机、通信等各种技术的进步和发展,可以预见,人工智能技术在继电保护领域必会得到应用,以解决用常规方法难以解决的问题。 3.4 综合自动化

现代计算机技术、通信技术和网络技术为改变变电站目前监视、控制、保护和计量装置及系统分割的状态提供了优化组合和系统集成的技术基础。高压、超高压变电站正面临着一场技术创新。实现继电保护和综合自动化的紧密结合,它表现在集成与资源共享、远方控制与信息共享。以远方终端单元(RTU)、微机保护装置为核心,将变电所的控制、信号、测量、计费等回路纳入计算机系统,取代传统的控制保护屏,能够降低变电所的占地面积和设备投资,提高二次系统的可靠性。

综合自动化系统打破了传统二次系统各专业界限和设备划分原则,改变了常规保护装置不能与调度(控制) 中心通信的缺陷,给变电所自动化赋予了更新的含义和内容,代表了变电所自动化技术发展的一种潮流。随着科学技术的发展,功能更全、智能化水平更高、系统更完善的超高压变电所综合自动化系统,必将在中国电网建设中不断涌现,把电网的安全、稳定和经济运行提高到一个新的水平。