A holistic approach for analyzing communication utilization inpower system control

Efficient handling of the communication resources is vital in power control systems. In this paper, a holistic approach is introduced for analyzing utilization of concurrent capabilities of communication. The approach embodies a trade-off between various parameters, such as bit rate, error rate, and latency. The approach has been applied to communication between a control center and remote terminal units, where half duplex is replaced by full duplex communication. However, it is general enough to be applied to other similar communication scenarios     

利用CPLD实现故障诊断专家系统高速逻辑推理

专家系统的推理时间取决于问题的复杂程度,难以满足系统实时性要求,限制了其应用。对此,提出一种利用复杂可编程逻辑器件(CPLD)实现故障诊断专家系统高速推理的方法。详细分析了一般故障诊断专家系统推理过程;利用故障树的概念将专家知识转换为二值或多值推理,并用一般门电路,进而利用CPLD实现推理过程;将其应用于高压断路器故障诊断系统,代替原来的软件推理。经过实验验证,该方法实现的专家系统推理过程迅速,特别适用于基于单片机、数字信号处理器(DSP)等所实现的专家系统。     

故障诊断专家系统高速模糊推理的CPLD实现

根据传统模糊推理的原理.提出了一种利用复杂可编程逻辑器件(CPLD)实现故障诊断专家系统高速模糊推理的模块化设计方法.该方法根据ROM存储器函数变换原理,在同一ROM内实现多种数据和多种类型的模糊变换与运算,利用CPLD器件实现模糊推理过程的协调与控制;将CPLD实现的推理控制与协调机构根据通用性划分为多个子模块,利用通用模块组装的形式搭建整个推理过程.从而将传统的软件模糊推理过程用模块化的硬件实现.实验证实,该方法实现的模.糊推理过程设计简单.推理速度也明显高于传统的软件推理,特别适用于基于单片机、数字信号处理器(DSP)等小规模CPU所实现的专家系统模糊推理.     

An autosynthesizing non-linear control system using a rule-based expert system

An advanced non-linear control system is obtained by combining recent developments in non-linear control system synthesis with a rule-based system approach to real-time control. The basic problem to be addressed is the control of a non-linear plant which is sufficiently sensitive to both operating point and input amplitude that the desired control system performance can be obtained only with a non-linear controller that is ‘retuned’ or ‘resynthesized’ whenever the operating point changes significantly. (The term ‘changes significantly’ in this context signifies an operating point change that causes the non-linear control system input/output behaviour to change substantially in an undesirable way.) This is accomplished by a hierarchically organized intelligent control system with a conventional reprogrammable controller under the direction of a rule-based expert system. The function of the expert system is to (i) monitor the behaviour of the non-linear control system to determine when retuning or resynthesis is required; if the behaviour is satisfactory, then continue passive monitoring; else (ii) when retuning or resynthesis is required: set up and execute experiments to derive the model information required to tune or synthesize a new non-linear controller in terms of a given structure and parametrization; execute the retuning/resynthesis procedure; reprogramme the controller (download the parametrization); and recommission the updated non-linear control system and return to normal operation. In essence, the rule-based system provides supervisory control (‘meta-control’) for a conventional reprogrammable non-linear controller that will autotune or autosynthesize as required. Autosynthesis takes place to accommodate variability in plant behaviour due to operating point changes, and the nonlinear controller thus synthesized corrects for amplitude sensitivity. This concept represents one way to combine artificial intelligence with control; it will be discussed and illustrated by example below.     

An expert system prototype for event diagnosis and real-timeoperation planning in power system control

A prototype system called EKA, which is an attempt to apply sophisticated knowledge-engineering methods to power systems, is described. EKA is based on an object-oriented model and model-based reasoning, including multiple ways to represent knowledge: rules, facts, methods, daemons, procedures, logic programs, etc. The EKA system consists of three separate but structurally similar systems: an operation planning system, an event analysis system, and a training simulator. As a development environment, hybrid software and a Lisp computer have been used. The tasks and methods involved are described with and without an expert system. The application environment and prototype implementation are outlined     

An expert system for voltage and reactive power control of a powersystem

A methodology called the sensitivity tree, which can be easily used to form an expert system for real-time control, is proposed. Based on this methodology, an expert system for the control of voltage and reactive power of a power system is developed. The main objective of this expert system is to help the operator detect buses experiencing abnormal conditions, select the most effective control measures, and calculate the control actions required to overcome the voltage violation. The control measures used to alleviate the voltage problem are capacitor compensation, transformer tap changes, and generator terminal voltage changes. By keeping the bus voltage in the entire system within limits, system security is increased. The expert system is written in the PROLOG language. Simulation studies with this expert system applied to a 30-bus power system show satisfactory results     

Adaptive multiple fault detection and alarm processing for loop system with probabilistic network

This paper presents the fault detection and alarm processing in loop system with fault detection system (FDS). FDS consists of adaptive architecture with probabilistic neural network (PNN). Training PNN uses the primary/backup information of protective devices to create the training sets. However, when network topology changes, adaptation capability becomes important in neural network applications. PNN can be retained and estimated effectively. With a looped system, computer simulations were conducted to show the effectiveness of the proposed system, and PNN's adapt network topology changes.     

An expert system for monitoring psychiatric treatment

A number of medical expert systems have been developed to address problems in health care, but there have been few applications to date for psychiatric practice. We have previously discussed design and implementation issues specific to this medical specialty, and have described OVERSEER, a prototype expert system for monitoring drug treatment in a psychiatric setting. Since its initial implementation, this prototype has been substantially modified based on clinical experience, and in this article we report on the operation and evaluation of the resulting “Clinical Evaluation and Monitoring System” (CEMS). CEMS addresses the essential elements of the clinical process-assessment, diagnosis, and treatment. The Pharmacotheraapy Guidelines contain information about psychiatric medications (e.g., dosages, therapeutic serum levels, indications and side effects), and they reflect the institutions' “standards of practice”. The Diagnostic Checklists (DCLs) provide an automated method for (1) assuring documentation of the key symptoms and behavioral issues noted in the patient assessment, and (2) noting the degree of change in each symptom/behavior at the time of the discharge (or other) evaluation. The Outcome Assessment module provides data about patients' functional, social, and vocational status at admission and discharge, and at three, six, and twelve months post-discharge     

引入事例推理的牵引变电所故障分析专家系统

传统的电气化铁道牵引变电站故障分析专家系统多采用基于规则推理(BRB)的方法,获取知识困难,推理速度较慢,自学习能力较差,很难适应铁路牵引网发展的需求.文中介绍了引入事例推理的方法,将事例库分为知识库、一般事例库以及特殊事例库,使系统故障分析更加快速可靠,动作评价准确,克服了传统专家系统获取描述准确知识困难的瓶颈,提高了自学习能力.     

基于模糊控制的智能火灾报警系统

针对火灾频繁发生问题,设计了一款能实现温度及烟雾浓度检测的智能火灾报警系统。该系统以MQ 2烟雾传感器、DHT11温度传感器和FIGARO TGS 813传感器为火灾探测器,STM32F103ZET6为控制系统核心,应用模糊控制理论提高了系统的精度,同时减少了误报率,实现火灾自动声光报警并通过无线Wi Fi传输数据,由GSM远程通信发送报警信息至手机用户端。经过反复实验测试基于模糊控制的智能火灾报警系统具有较强的实用性,适用范围广,适用于智能家居的安防系统。     

引入事例推理的牵引变电所故障分析专家系统

传统的电气化铁道牵引变电站故障分析专家系统多采用基于规则推理(BRB)的方法,获取知识困难,推理速度较慢,自学习能力较差,很难适应铁路牵引网发展的需求。文中介绍了引入事例推理的方法,将事例库分为知识库、一般事例库以及特殊事例库,使系统故障分析更加快速可靠,动作评价准确,克服了传统专家系统获取描述准确知识困难的瓶颈,提高了自学习能力。     

电网调度控制系统告警信息的优化处理

自调控一体化运行模式实行以来,电网调度控制系统接收的告警信息量越来越大,告警信息处理不当,会严重影响监控人员对电网故障判断的及时性和准确性。基于国网银川供电公司电网调度控制系统,首先介绍了告警信息的产生与分类,然后分析了告警信息处理方面存在的3个问题,最后提出了告警信息压缩处理、告警信息加延时处理、开发告警信息智能巡检工具等优化措施。经实践验证,该措施有效可行,可实现告警信息的优化处理效果。     

An expert system for high-voltage substations lightning performanceestimation

A computer-based expert system approach to the detailed lightning performance evaluation of high-voltage overhead lines and substations is described. All parameters causing the computation result uncertainty are systematized and analyzed. The importance of the optimal equivalent circuit design is emphasized. For a 400 kV substation layout the sensitivity study of the parameters of the equivalent circuit is performed and an optimal circuit is evaluated. The lightning and the computing parameters are studied and the default values for practical application are suggested. Some of the software possibilities using a multilevel menu system are presented. A statistical approach to the substation lightning performance estimation based on the discharge point moving along the span of the connected overhead line in front of the analyzed substation entrance is described     

Flexible open architecture design for power system control centers

That the new generation power system control centers need a paradigm shift in their architectural design to meet new challenges, is an established conclusion of many researchers. However, literature on comprehensive architectural design towards this direction is scarce. In this paper, an information architecture design is proposed for the power system control centers. Appropriate adoption of open standards such as the common information model (CIM) is endorsed. Further, initial development of an event information model for modeling high level power system events is mentioned. Proposed architecture focuses on the desired features such as openness, interoperability, flexibility, scalability, vendor independence and event orientation. The architecture comprises services arranged in layers, viz., data integration and access, event processing and plug-in services. The details of this architecture along with the intricate relationships between various layers and services depicting how the technologies could be integrated into a coherent whole are described in this paper. An illustrative example, from the Indian power sector domain has been used to demonstrate the usefulness of the proposed architecture.     

集控自动化系统报警方案的设计与实施

从运行人员工作习惯与需求出发,结合集控自动化系统运行特点,侧重于实际工程配置,描述了某集控系统信号告警的具体实施方案。     

An expert system for security trend analysis of a stability-limitedpower system

An expert system for dynamic security assessment (DSA) is described in which artificial intelligence techniques are applied to the transient energy function (TEF) method. The effect of contingencies on the security level and its rate of change with changing system conditions and parameters are computed using the results of the TEF sensitivity analysis program. The expert system determines the loading trend and analyzes the data obtained from TEF to compute the trend of the security index. The trend of the control parameters can then be adjusted to maintain the security index within a range of safe values. An example is given using data collected from the Northern States Power Company (NSP) where the expert system correctly computed the security index and suggested adjustments to system parameters     

地方电网继电保护整定计算专家系统的研究

应用面向对象的方法 ,结合地方电网的实际特点 ,开发了一套分散式的继电保护整定计算专家系统。该系统把数据和知识库分散封装于不同的对象 ,通过消息传递进行相互配合 ,能较好地完成数值计算和逻辑推理 ,实验结果令人满意 ,目前整个系统正在完善中     

地方电网继电保护整定计算专家系统的研究

应用面向对象的方法,结合地方电网的实际特点,开发了一套分散式的继电保护整定计算专家系统.该系统把数据和知识库分散封装于不同的对象,通过消息传递进行相互配合,能较好地完成数值计算和逻辑推理,实验结果令人满意,目前整个系统正在完善中.     

An expert system for substation fault diagnosis and alarmprocessing

An expert system for substation fault diagnosis and alarm processing developed by the Electric Power Systems Laboratory of the National Technical University of Athens is presented. It is written in Turbo Prolog and is implemented on a personal computer. The system includes many characteristics of an expert system cell because it can be expanded easily by adding new information to its knowledge base or by changing the existing information. The basic idea behind this system is to provide a nonexpert with the necessary information and interaction in order to make a fault diagnosis through the substation alarms in a very friendly environment. The main task of the system is to replace the troubleshooting manuals of substation equipment and human expertise in substation fault diagnosis and alarm processing with a user-friendly computer environment and to take advantage of the user's accumulated experience to expand and modify the knowledge base of the expert system. The expert system can be connected directly to a PC-SCADA system through a simple software interface written in C for online data acquisition