new IEEE Guidefor the Selection ofMonitoring for Circuit Breakers has been ... made self-regulating, oil-free, and able to correct power quality prob- lems.
Operation of Impedance Protection Relays with the STATCOM El-Arroudi, K.; Joos, G.; McGillis, D. Author Affiliation: McGill University, Montreal, Quebec, Canada Abstract: This paper presents analytical and simulation results for investigating the operation of impedance-based protection relays in a
power system containing a flexible alternating current transmission (FACTS) controller such as static synchronous compensator (STATCOM). The analyses are based on steady state operation for modeling the STATCOM and the protection relays. The impact of the FACTS device on protection relays is studied for normal operating conditions as well as for fault conditions under different loading levels. Results for a case study are given. Keywords: Power system protection, power system relaying static VAR compensators, FACTS devices. Preprint Order Number: PE-103PRD (12-2001) Discussion Deadline: May 2002
Switchgear Strategies for Selecting Monitoring of Circuit Breakers Sweetser, C.; Bergman, W.J.; Montillet, G.; Mannarino, A.; O'Donnell, EJ.; William Long, R.; Nelson, J.; Gavazza, R.; Jackson, R. Author Affiliation: Doble Engineering; Powr System Solutions; Alstom Power Transmission; PSEG' Baltimore Gas & Electric, MD;
Cutler-Hammer; TVA; Pacific Gas and Electric; Detroit Edison, MI Abstract: Diagnostics and monitoring can be used to optimize maintenance practices, replacement, and utilization of aged circuit breakers. Monitoring practices should be selected with realistic expectations. Monitoring techniques and strategies for circuit breakers can vary depending on the application. Some monitoring techniques do not provide sufficient benefit to justify the cost and effort. Conversely, appropriate selection of monitoring can provide significant benefits. A new IEEE Guide for the Selection of Monitoring for Circuit Breakers has been published. It outlines the majority of monitoring options and includes the important role and application of failure modes and effect analyses. Various monitoring techniques and strategies are reviewed using the new guide as a reference for selecting the most appropriate monitoring for a given application Preprint Order Number: PE-583PRD (12-2001) Discussion Deadline: May 2002
Transformers How to Avoid Unstable Time Domain Responses Caused by Transformer Models Henriksen, T. Author Affiliation: SINTEF, Norway Abstract: Modeling a three-winding transformer occasionally
gives a negative reactance that may result in an unstable circuit. This unstable condition can be eliminated by neglecting the magnetizing losses or taking them into account in a different way, as shown in this paper. Unstable responses are under certain conditions extremely dependent on the time step when using EMTP or similar programs. This paper shows why simulated terminal voltages do not always reveal an unstable circuit condition. Keywords: Transformers, modeling, negative inductance, unstable circuit, time domain analysis. IEEE Power Engineering Review, March 2002
Preprint Order Number: PE-428PRD (12-2001) Discussion Deadline: May 2002
A Power Electronic-Based Distribution Transformer Ronan, E.R.; Sudhoff, S.D.; Glover, S.F.; Galloway, D.L. Author Affiliation: University of Missouri-Rolla, Rolla, MO; Purdue University, West Lafayette, IN; Consultant Abstract: The distribution transformer has been in use by utilities throughout the twentieth century. Until now, it has consisted of a configuration of iron or steel cores and copper/aluminum coils, with mineral oil serving as both coolant and dielectric medium. Inherent in this type of construction are regulation, significant weight, losses, environmental concerns, and power quality issues. A new kind of distribution transformer is proposed for the twenty-first century, one that can be made self-regulating, oil-free, and able to correct power quality problems. A power electronic transformer has been analyzed, simulated, prototyped, and tested. Results of this effort, as well as the novel features of this new type of transformer, are discussed herein. Keywords: Converters, power conversion, power electronics, transformers. Preprint Order Number: PE-920PRD (12-2001) Discussion Deadline: May 2002
Impedances for the Calculation of Electromagnetic Transients Within Transformers Mombello, E.E. Author Affiliation: Universidad Nacional de San Juan Abstract: In this paper, a deep analysis of the behavior of transformer winding impedances for high frequencies is performed. The properties of inductance matrices are analyzed, as well as the possibility of making assumptions and their range of validity. The properties of resistance matrices are also analyzed, which has not been made in the past. The discussion on the influence of the iron core on inductance and resistance matrices is undertaken. The analysis is based on impedance measurements carried out on experimental transformer windings. Finally, recommendations are made about which are the most suitable impedance models for modeling transformers impedances during transient and resonance calculations. Keywords: Electromagnetic transient analysis, impedance, power
transformers, resonance.
Preprint Order Number: PE-040PRD (12-2001) Discussion Deadline: May 2002
A New Adaptive PMU-Based Protection
Scheme for Transposed/Untransposed Parallel Transmission Lines
Chen, C.S.; Liu, C.W; Jiang, J.A. Author Affiliation: National Taiwan University, Taiwan Abstract: This paper proposes a brand-new adaptive phasor measurement unit (PMU)-based protection scheme for both transposed and untransposed parallel transmission lines. The development of the scheme is based on the distributed line model and the synchronized phasor measurements at both ends of lines. The fault detection and location indices are derived by means of eigenvalue/eigenvector theory to decouple the mutual coupling effects between parallel lines. The two proposed indices are used in coordination such that the internal and external fault events can be distinguished completely. By on-line estimating the line parameters under the actual power system conditions, the proposed scheme will respond more accurately to power system faults. Extensive simulation results using EMTP have verified that the accuracy of the fault location achieved is up to 99.9%. The proposed protection system responds well and fast with regard to dependability and security. All the results show that the performance of the proposed detection/location indices is independent of fault types, locations, resistance, source impedance, fault inception angles, and load flows. 61
