A failure in a power transmission line causes a number of circuit breakers to activate in an effort to isolate the failure and prevent it from corrupting the rest of the power system. Based on information from these physically distributed protective devices, a central controller needs to quickly locate and identify the failure. The task becomes challenging due to the complexity of modern power transmission networks and due to the possibility of sensor failures or incorrect operation of protective devices. A solution to this problem is investigated using Petri net models. Our approach allows concurrent/incremental processing of the information that arrives at the controller and only requires simple calculations (linear checks) during execution time. Most reasoning is implicitly performed at design time, which gives our method an important edge for real-time monitoring. These same techniques can potentially handle multiple failures or perform hierarchical and/or distributed monitoring.

Power system monitoring using Petri net embeddings

In this paper we develop monitoring schemes that are able to detect and identify failures in power transmission lines by analyzing binary status information from relays and circuit breakers. The approach, which is based on Petri net models, requires very simple calculations (linear checks) during execution time and allows for concurrent/incremental processing of the information as it arrives at the control center.

Power system monitoring based on relay and circuit breaker information

Experimental learning about electric-machinery is high risk and time-consuming, students do not always enjoy the laboratory, the teacher also needs to pay full attention to all students and equipment, besides it is hard to provide enough machine sets and space for learning. So it is our motivation to design a virtual laboratory for the teaching of electric-machinery experiment by Internet under the more real environment without concern about danger or limitations. It is taught by an experienced teacher using a pedagogical agent which is the most important key factor. Taking the above features into consideration, an interactive virtual laboratory based on an expert system has been designed and implemented to improve the learning, operation and control in electric-machinery experiments. The system set up is a highly intelligent and interactive mechanism. Through the system, students could have a more complete environment for distance learning.

The design of pedagogical agent for distance virtual experiment

This paper has developed a PC based energy management system associated with automatic meter reading and various load control functions for load management of industrial and commercial customers. Automatic meter reading configured by a programmable logic controller and power meter supports the function of recording 20 power parameters retrieved from an academic substation. Load control functions; which consist of demand control, timer control, cycling on/off control and direct control, are designed to effectively reduce peak load and to save electrical energy. Several types of software program coded by Visual Basic, PLC ladder language, and partial Diamond package, are designed to integrate all hardware equipment in energy management system. The entire system has been installed and successfully operated since October 1997. Statistical data collected from 1997/10 to 1999/10 indicate that the proposed effect for peak load cutting and energy saving may be justified.

Development of PC based energy management system for electrical energy saving of high voltage customer

A static VAr compensator (SVC) is used to compensate reactive power and improve power quality and plays a more and more important role in the power industry. By applying modern computer technology, a complex multifunction monitoring system can be constructed with shorter time and less cost. Laboratory Virtual Instrument Engineering Workbench (LabVIEW), one of the prevalent graphic developing tools, is always endeavoring to put the virtual instrument concept into practice. This paper presents the detailed construction procedures and features of the SVC monitoring system based on an industrial computer with LabVIEW, including hardware considerations and software implementation; and then summarizes essential points of constructing a computer-based monitoring system.

http://ieeexplore.ieee.org/iel5/8110/22495/01067864.pdf

Computer-based monitoring system of static VAr compensator

Modern industrial production processes have always been supervised and/or controlled in many different ways. The evolution of control methods was motivated by technological advances and by the requirements of the processes themselves. Many processes are supervised and controlled in an automated environment due to improvements in electronics and computer science. In the electric power industry, there is a strong need to control and supervise the production and distribution of energy, so as to avoid possible power failures. The supply of energy must always be guaranteed (even in adverse conditions), and control involves different systems (high and low voltage lines, compensation, and filtering systems, etc.), so operators require quick and reliable access to meaningful information. The option to interfere in some processes must be provided. All these goals are accomplished using an appropriate control architecture, communication networks, and symbolic representation of electrical network systems. Operator efficiency will be assured if these requirements are met. There are no unique guidelines for developing electrical monitoring projects, since any choice will depend on many specific variables; however, the most important points to take into account are as follows.

http://ieeexplore.ieee.org/iel3/67/12213/00560857.pdf

M.C.S.-C. Roldan

Papers

Developing an electrical distribution monitoring system