EUROPEAN TRANSACTIONS ON ELECTRICAL POWER Euro. Trans. Electr. Power 2010; 20:1–2 Published online in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/etep.403
Editorial Special Issue on power quality
Providing power quality (PQ) for 21st century needs is one of the key characteristics in a system view of the modern grid. Electric PQ has been an important aspect of power engineering studies since the inception of power systems. A PQ disturbance can result in substantial costs to the system operation. Most commonly seen PQ events are associated with sags (dips), harmonics/ interharmonics, transients, and system frequency variations. While the majority of PQ disturbances may arise from the power grid and are the responsibility of the utility, other PQ problems are the responsibility of the customer. Therefore, monitoring, prevention, and mitigation of PQ disturbances are of great concerns for both parties. To achieve these goals, many PQ issues still remain as challenging tasks. This special issue features the following six papers: (1) Bollen, M., Ribeiro, P., Gu, I., C. Duque, Trends and Challenges in Power Quality Research. This paper highlights new areas of interests and future trends in PQ issues and concerns. Factors such as the increase of distributed generation, demand of energy efficiency, and proliferation of power electronics technologies have presented challenges and opportunities for the PQ studies. (2) Watson, N., Power Quality State Estimation. This paper provides an overview of the state-of-the-art techniques currently available for PQ state estimation (PQSE) in a large power network. The reviewed PQSE techniques include harmonic state estimation and identification of harmonic sources, transient state estimation, and voltage sag state estimation. The improvement of PQ monitors and data communication in the foreseeable future will help realize the PQSE for actual applications. (3) Barrera Nunez, V., Melendez Frigola, J., Herraiz Jaramillo, S., Sanchez Lozada, J., Evaluation of Fault Relative Location Algorithms using Voltage Sag Data Collected at 25-kV Substations. This paper performs an evaluation of six recently proposed algorithms for identifying the relative location of a voltage sag source. The features and rules used with these algorithms have been qualitatively and statistically analyzed, and this analysis carried out with real data to assess the on-line applicability of the methods. The algorithms were evaluated with 471 asymmetrical faults collected by PQ monitors installed on the secondary sides of distribution network transformers. (4) Bhattacharyya, S., Cobben, S., Myrzik, J., Kling, W. L., Flicker Propagation and Emission Coordination Study in a Simulated Low Voltage Network. In this paper, a typical low voltage network model is developed based on real data of the Dutch networks. A number of simulations are performed to analyze the flicker propagation behavior in the networks. Results show that the flicker severity values obtained from the analysis of various cases are in line with the expected results. (5) Langella, R., Sollazzo, A., Testa, A., A New Approach for the Computation of Harmonics and Interharmonics Produced by AC/DC/AC Conversion Systems with PWM Inverter. This paper presents a new inverter model that takes into account the voltage ripple at the inverter input terminals for assessment of harmonics and interharmonics produced by AC/DC/AC conversion systems with pulse-width modulation inverters. The proposed model has been successfully applied to adjustable speed drives for synchronous motors with high solution accuracy and computational efficiency. (6) Xu, W., Tayjasanant, T., Zhang, G., Bahry, R., Mitigation of Interharmonics Using a Switched Filter Scheme. This paper presents a real-life case where a variable frequency drive causes voltage flicker and a switched filter scheme is proposed to resolve the problem. Field measurements are then conducted to validate the effectiveness of the proposed filter scheme.
Copyright # 2010 John Wiley & Sons, Ltd.
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EDITORIAL
These articles cover a wide range of PQ topics and provide an excellent view of the current and future trends, as well as technical challenges and solutions. The authors are acknowledged for their valuable contributions to this special issue. Gary W. Chang Guest Editor Department of Electrical Engineering National Chung Cheng University Chia-Yi 621, Taiwan, Republic of China
[email protected] Surya Santoso Guest Editor Department of Electrical and Computer Engineering University of Texas at Austin, Austin 78712, TX, USA
Copyright # 2010 John Wiley & Sons, Ltd.
Euro. Trans. Electr. Power 2010; 20:1–2 DOI: 10.1002/etep
