Jaime De La Ree

Synchronized Phasor Measurement Applications in Power Systems

Synchronized phasor measurements have become a mature technology with several international manufacturers offering commercial phasor measurement units (PMUs) which meet the prevailing industry standard for synchrophasors. With the occurrence of major blackouts in many power systems around the world, the value of data provided by PMUs has been recognized, and installation of PMUs on power transmission networks of most major power systems has become an important current activity. This paper provides a brief introduction to the PMU and wide-area measurement system (WAMS) technology and discusses the uses of these measurements for improved monitoring, protection, and control of power networks.

Performance evaluation of PM machines with quasi-square input currents

ABSTRACT This paper presents an analytical method to determine the instantaneous electromechanical torque on PM machines for a known quasi-square phase current and the corresponding maximum, minimum, average and pulsating torque. The influence of some of the design parameter on the performance of the machine will be investigated on this paper.

Partitioned linear state estimation

This paper presents the idea of a partitioned linear state estimator (PLSE) as an alternative to the classical linear state estimator (LSE). PLSE is found to be especially useful for performing state estimation in large systems comprising of multiple entities. The best example of this is different utilities functioning under an independent system operator (ISO). The proposed technique is immune to the number of tie-lines that exist between the utilities as well as the number of utilities that are present under the ISO. Its biggest advantage is that it reduces discrepancies occurring at the boundaries while requiring minimum exchange of information between the utilities. The IEEE-14 bus system is used as the test system for presenting the idea. The results indicate that PLSE is a robust method for performing state estimation in big systems.

Synchronized rotor angle measurement of synchronous machines

A key input parameter to governor feedback control and stability protection of generators is the angle of the induced voltage internal to the generator. Current practice is to estimate this value using measurements from the terminals of the generator and mathematical models. This project aims to develop a system that would directly measure the internal angle of the generator using a rotary encoder on the shaft of the machine. This document describes the theory and experimental setup of this proposed system and outlines the test procedure of experimentation.

Development of a pulsatile, tissue-based, versatile vascular surgery simulation laboratory for resident training

Simulation in surgery is becoming an important component of surgical education. Training on bench top models has been demonstrated to improve technical skills. The objective of our project was to create a vascular surgery simulation model. The simulation model consists of a platform, artificial blood reservoir, artificial blood, inflow and outflow limbs, electric motor, battery, pulse generator, and cryopreserved vessel. Three different vascular surgery simulation stations were created: carotid endarterectomy with shunting and patch angioplasty, arterial bypass, and arteriovenous graft formation. A scientific study involving surgical residents will need to be undertaken to determine whether this simulator has intermodal transferability.

Capacitor bank model validation with particle swarm optimization algorithm

In most substation protection studies, capacitor bank parameters are derived from manufacturer nameplate values. However, the actual parameters could be different from the nominal rating as a result of manufacturing variance, assembling, material aging, and temperature dependencies. Wide manufacturing tolerance could lead to non-negligible calculation inaccuracy that affecting successive studies. For impedance based protection, inaccurate parameters for relay settings can also cause mal-operation. In this paper, the field current and voltage measurements are used to validate the size of capacitor bank and the capacitor ratings. A 10-15% deviation between the instantaneous current peak measurements and simulation results from capacitor bank model is observed. This paper introduces, the use of particle swarm optimization algorithm to fine tune parameters for possible relay settings. MATLAB simulation shows that a set of capacitor bank parameters is yielded by PSO algorithm through reducing normalized deviation between field measurements and simulation to around 4% - 5%.

Visual Modeling of a Current Transformer's Hysterisis

This paper presents an approach to model current transformers (CTs) by visual inspection of hysterisis loops. Three parameters on CT hysterisis loops reveal enough information about the core-loss and non-linear magnetizing inductance that power measurements and flux-current data-pairs can be avoided. To validate the proposed model, an experimental CT is saturated with energizations and compared to simulation results. Overlays of the experimental energizations, the proposed modeling approach, and the traditional piecewise-linear approach are compared.

Implementation of a purely digital substation system using the IEC 61850 standard

This paper presents an entirely digital system which has several benefits as compared to the systems that are deployed currently. Utilizing digital capabilities to a much greater extent than is currently used within the power system allows for various improvements upon the current system. One such improvement is the ease of configuring and using the system. Each device can easily alter its functionality through a user interface, and the addition of devices is as easy as plugging it in. Additionally, the burden on the transformer due to the increase in the number of devices is nullified. The information remains accurate and unchanged, even when new devices are added to the system. The entire system conforms to the IEC 61850 standard, such that it adheres to the requirements of the actual power system.

Synchronized rotor angle measurement using microprocessors

The internal voltage angle of generators is an important parameter that indicates the stability, both transient and steady-state, of a generator. This paper proposes a method of measuring and then synchronizing the internal angle with the use of an optical encoder on the shaft using a microprocessor. With a synchronized angle measurement, accurate stability studies and wide-area controls could be implemented. The experimental setup up of measuring the rotor angle of a generator, and as such the internal angle, is explained in this paper.