R.D. Findlay

Bio: R.D. Findlay is an academic researcher from McMaster University. The author has contributed to research in topics: Induction motor & Eddy current. The author has an hindex of 15, co-authored 94 publications receiving 865 citations. Previous affiliations of R.D. Findlay include University of Southampton & University of New Brunswick.

Electro-mechanical analysis of the audible noise of an inverter-fed squirrel-cage induction motor

Abstract: The audible noise emitted by a three-phase squirrel cage induction motor fed by a frequency inverter is determined by the electromagnetic and mechanical behavior of the components of the drive. A computerized analysis method is described that uses theoretical and experimental data for predicting the audible noise spectrum components. Starting from the inverter voltage and the motor data, the electromagnetic forces are predicted and analyzed. The mechanical natural frequencies are considered, either in a theoretical (finite element calculation) or in an experimental (modal analysis) methodology, to predict the vibrational behavior of the machine. The scheme contains the following steps: analysis of the frequency spectrum of the inverter used; synthesis of the magnetic force spectrum accounting for the motor data: calculation or measurement of the resonant data of the stator assembly; and comparison of the force spectrum and the resonant data. These various steps are discussed. >

Losses due to rotational flux in three phase induction motors

Abstract: This paper discusses rotational losses and how they are produced in the core materials of induction motors. These losses are largely caused by flux that rotates in the plane of the machine laminations. This suggests that steel specification for applications to rotating machines should be given in terms of rotational loss data as a material characteristic, in much the same fashion as Epstein test results are provided for alternating losses. If a standardized test for rotational losses were to be used, steel producers could rationally investigate the effects of composition and processing variables. This is necessary in order to produce low loss steels for motor applications. Reduction of rotational losses in motor cores could significantly lower AC machine operating costs and contribute to the growing interest and design of high efficiency induction motors. The paper describes a test procedure for determining rotational losses in a sample. It then compares the results with standardized tests from an Epstein test procedure. It is seen that there are significant differences in loss results obtained for the rotational test versus the alternating current test. The authors have investigated a time harmonic finite element formulation utilizing Magnet 2D, a commercially available package. The paper includes a brief analysis of a typical problem using this tool. >

Stray Losses in Induction Machines: Part I, Definition, Origin and Measurement

Abstract: The state of the art of stray load losses in induction machines is discussed with respect to definition, origin and effects, and measurement techniques. The historical search for a definitive evaluation technique for these losses is discussed together with the recognized criticisms of each approach. It is noted that although this subject has been the object of intensive investigations for more than seventy years there is still very little agreement on either the origin or evaluation of stray load loss. This paper discusses the major works in the area with the objective of delimiting the problem so that a rational approach for future work may be promulgated.

A New Model of AC Resistance in ACSR Conductors

Abstract: An accurate new model for calculating AC resistance of ACSR conductors has been developed and verified for single, two and three layer conductor designs. Current redistribution was found to be far more important in determining the AC/DC resistance ratio than hysteresis losses in the steel core except in single layer conductors. The model suggests ways of reducing the AC resistance and promises to be a useful design tool.

Power System Dynamics and Stability

Abstract: 1 Introduction 2 Electromagnetic Transients 3 Synchronous Machine Modeling 4 Synchronous Machine Control Models 5 Single-Machine Dynamic Models 6 Multimachine Dynamic Models 7 Multimachine Simulation 8 Small-Signal Stability 9 Energy Function Methods Appendix A: Integral Manifolds for Model Bibliography Index

A review on artificial intelligence based load demand forecasting techniques for smart grid and buildings

Abstract: Electrical load forecasting plays a vital role in order to achieve the concept of next generation power system such as smart grid, efficient energy management and better power system planning. As a result, high forecast accuracy is required for multiple time horizons that are associated with regulation, dispatching, scheduling and unit commitment of power grid. Artificial Intelligence (AI) based techniques are being developed and deployed worldwide in on Varity of applications, because of its superior capability to handle the complex input and output relationship. This paper provides the comprehensive and systematic literature review of Artificial Intelligence based short term load forecasting techniques. The major objective of this study is to review, identify, evaluate and analyze the performance of Artificial Intelligence (AI) based load forecast models and research gaps. The accuracy of ANN based forecast model is found to be dependent on number of parameters such as forecast model architecture, input combination, activation functions and training algorithm of the network and other exogenous variables affecting on forecast model inputs. Published literature presented in this paper show the potential of AI techniques for effective load forecasting in order to achieve the concept of smart grid and buildings.

Effects of harmonics on equipment

Abstract: The authors summarize the state of knowledge of the effects of power system harmonics on equipment. The general mechanisms presented are thermal overloading, disruption, and dielectric stressing. Quantitative effects are presented or referenced whenever possible. However, many of the effects are can only be qualitatively described. The types of equipment considered are adjustable speed drives, capacitors, circuit breakers, fuses, conductors, electronic equipment, lighting, metering, protective relays, rotating machines, telephones, and transformers. >

Direct stability analysis of electric power systems using energy functions: theory, applications, and perspective

Abstract: Stability analysis programs are a primary tool used by power system planning and operating engineers to predict the response of the system to various disturbances. Important conclusions and decisions are made based on the results of stability studies. This paper presents a theoretical foundation of direct methods for both network-reduction and network-preserving power system models. In addition to an overview, new results are offered. A systematic procedure of constructing energy functions for both network-reduction and network-preserving power system models is proposed. An advanced method, called the BCU method, of computing the controlling unstable equilibrium point is presented along with its theoretical foundation. Numerical solution algorithms capable of supporting online applications of direct methods are provided. Practical demonstrations of using direct methods and the BCU method for online transient stability assessments on two power systems are described. Further possible improvements, enhancements and other applications of direct methods are outlined.