Power system loading margin is a fundamental measure of a system's proximity to voltage collapse. Linear and quadratic estimates to the variation of the loading margin with respect to any power system parameter or control are derived. Tests with a 118-bus system indicate that the estimates accurately predict the quantitative effect on the loading margin of altering the system loading, reactive power support, wheeling, load model parameters, line susceptance and generator dispatch. The accuracy of the estimates over a useful range and the ease of obtaining the linear estimate suggest that this method will be of practical value in avoiding power system voltage collapse.

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Sensitivity of the loading margin to voltage collapse with respect to arbitrary parameters

This task force paper summarizes the state-of-the-art real-time digital simulation concepts and technologies that are used for the analysis, design, and testing of the electric power system and its apparatus. This paper highlights the main building blocks of the real-time simulator, i.e., hardware, software, input-output systems, modeling, and solution techniques, interfacing capabilities to external hardware and various applications. It covers the most commonly used real-time digital simulators in both industry and academia. A comprehensive list of the real-time simulators is provided in a tabular review. The objective of this paper is to summarize salient features of various real-time simulators, so that the reader can benefit from understanding the relevant technologies and their applications, which will be presented in a separate paper.

Real-Time Simulation Technologies for Power Systems Design, Testing, and Analysis

We propose that the feedforward connection from the lower visual cortical area to the higher visual cortical area provides an approximated inverse model of the imaging process (optics), while the backprojection connection from the higher area to the lower area provides a forward model of the optics. By mathematical analysis and computer simulation, we show that a small number of relaxation computations circulating this forward-inverse optics hierarchy achieves fast and reliable integration of vision modules, and therefore might resolve the following problems. (i) How are parallel visual modules (multiple visual cortical areas) integrated to allow a coherent scene perception? (ii) How can ill-posed vision problems be solved by the brain within several hundreds of milliseconds?

https://www.tandfonline.com/doi/pdf/10.1088/0954-898X_4_4_001

A forward-inverse optics model of reciprocal connections between visual cortical areas

Artificial neural networks and their applications to power systems—a bibliographical survey

This paper presents the development of a unique parallel and distributed real-time digital simulator for power engineering research at the University of Alberta. The simulator is built entirely from commodity-off-the-shelf (COTS) hardware and software components, making it very flexible and scalable. In parallel multi-tasking operations, a combination of real-time Linux operating system and an ultra-fast network forms the backbone for the internal communication between the 16 powerful processors of the Xeon-Cluster. Field programmable gate array (FPGA)-based multi-channel digital and analog I/O ports are interfaced to communicate with the external hardware components. The model development software utilized for power applications is based on the highly customizable industry-standard MATLAB/SIMULINK environment. A detailed case study of the real-time simulation of a three-level 12-pulse vector-controlled ac drive is presented to illustrate the precision capabilities of the simulator. Multiple integration algorithms and multirate computation have been applied for the simulation of the system, with slow (machine) and fast (converter) dynamic components. Real-time simulation of the entire system has been achieved with a maximum computation time of 5.35 /spl mu/s on a step-size of 10 /spl mu/s for the first time. Results obtained from the real-time simulation have been validated with an offline simulation using PSCAD/EMTDC.

A versatile cluster-based real-time digital simulator for power engineering research

A digital simulator based on a hypercube-type massively parallel computer, the NCube2, has been developed. The simulator features: real-time simulation of a large power system which covers transient stability through long-term behavior with constant accuracy level in root mean square values; user-friendly man-machine interfaces which mimic the actual operating environment including interactive setting of several system parameters and real-time data presentation on a CRT; and high-speed A/D (analog to digital) converters, D/A (digital to analog) converters, and D/IO (digital input and digital output) interfaces are used to connect the digital simulator (power system dynamic model) to actual equipment. The authors describe the basic characteristics of the digital simulator and present results obtained in real-time simulations. >

Real-time digital simulator for power system analysis on a hypercube computer

Redundant coding for fault tolerant computing on Hopfield network

To understand a number of power system phenomena and to predict critical conditions in system operation, such as voltage collapse, a real-time simulator able to model the dynamic behavior of large power systems has been needed for a long time. The need for real-time simulations stems from the fact that in many practical situations it is desirable to test new equipment and analyze the dynamic behavior of a large power system using the actual pieces of equipment.



A new digital simulator was developed based on a hypercube-type massively parallel computer to achieve this objective. The new simulator features: (1) real-time simulation of a large power system which covers transient stability through long-term behavior with constant accuracy level; (2) user-friendly man-machine interfaces which mimics an actual operating environment and realtime data presentation on a CRT; and (3) high-speed digital/analog conversion interfaces which connect the digital simulator to actual equipment.

Hisao Taoka

Papers

Real-time digital simulator for power system analysis on a hypercube computer

Redundant coding for fault tolerant computing on Hopfield network

Real-Time Digital Simulator for Power System Analysis

A distributed simulator for power system analysis using a hypercube computer

Distributed Power System Simulation on a Hypercube Computer