• KIEE International Transactions on Power Engineering
• /
• v.4A no.4
• /
• pp.214-220
• /
• 2004

Power quality monitoring is the cornerstone for power quality analysis, diagnosis and improvement. The measurement of power quality (PQ) evolves from instantaneous metering to continuous monitoring. Furthermore, recent technologies enable us to construct more flexible, reliable, rapid and economical power quality monitoring system (PQMS). Therefore, this paper presents an improved PQMS with a new distributed monitoring structure. The proposed PQMS consists of a PQ meter, PQ analyzer and GUI. The PQ meter only collects raw data and the PQ analyzer performs power quality analysis. It has several advantages compared to conventional structures in economic efficiency, modularity, speed, etc. PQ monitoring algorithms to catch steady-state trends and to detect PQ events are also adapted to the proposed structure. Using the proposed structure and monitoring algorithm, a prototype PQMS is constructed and real-time testing is performed.

• Journal of Electrical Engineering and Technology
• /
• v.9 no.4
• /
• pp.1171-1181
• /
• 2014

Different power quality (PQ) disturbance sources can have major impacts on the power supply grid. This study proposes, for the first time, an early warning approach to identifying PQ problems and providing early warning prompts based on the monitored data of PQ disturbance sources. To establish a steady-state power quality early warning index system, the characteristics of PQ disturbance sources are analyzed and summed up. The higher order statistics anomaly detection (HOSAD) algorithm, based on skewness and kurtosis, and hierarchical power quality early warning flow, were then used to mine limit-exceeding and abnormal data and analyze their severity. Cases studies show that the proposed approach is effective and feasible, and that it is possible to provide timely power quality early warnings for limit-exceeding and abnormal data.

• Journal of Electrical Engineering and Technology
• /
• v.10 no.1
• /
• pp.92-101
• /
• 2015

As one type of power quality (PQ) disturbance sources, high-speed rail (HSR) can have major impacts on the power supply grid. Providing timely and accurate warning information for PQ problems of HSR is important for the safe and stable operation of traction power supply systems and the power supply grid. This study proposes a novel warning approach to identify PQ problems and provide warning prompts based on the monitored data of HSR. To embody the displacement and status change of monitored data, multi-features of different sliding windows are computed. To reflect the relative importance degree of these features in the overall evaluation, an analytic hierarchy process (AHP) is used to analyse the weights of multi-features. Finally, a multi-features similarity algorithm is applied to analyse the difference between monitored data and the reference data of HSR, and PQ warning results based on dynamic thresholds can be analysed to quantify its severity. Cases studies demonstrate that the proposed approach is effective and feasible, and it has now been applied to an actual PQ monitoring platform.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.17 no.1
• /
• pp.85-90
• /
• 2022

This study presents a Real-Time Power Quality(:PQ) Evaluation methodology that reflects customer's load characteristics. Author determined PQ as [Ideal], [Measured], [Acceptable], and evaluated measured PQ between Ideal and Acceptable by using Ideal AHP. Author determined Load as Resistance, Electric Motor, and Electronics, and evaluated PQ reflect Load characteristics. As future studies, author has plan to study 1:1 matrix and overall PQ evaluation including year-based PQ.

• 제어로봇시스템학회:학술대회논문집
• /
• 1997.10a
• /
• pp.1436-1439
• /
• 1997

The objective of this paper is to present an efficient and practical approach to the automatic classification of power quality(PQ) disturbances, where and orthogonal polynomial approximation method is emloyed for the detection and localization of PQ disturbances, and a feature vector, newly extracted form the bispectra of the detected signal, is utilized for the automatic rectgnition of the various types of PQ disturbances. To demonstrae the performance and applicabiliyt of the proposed approach, some simulation results are provided.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.19 no.4
• /
• pp.91-97
• /
• 2005

As the developing of industry, the nonlinear equipments as inverter, converter, SMPS(Switching Mode Power Supply) and motor have been increased. But the sensitive electronic loads to the power quality, such as computers and other electronic equipments, have been spreaded out very fast. Thus, the power quality(PQ) problems and the real time power quality monitering(PQM) are one of the important issues in industry and building area for the intelligent control of the systems. One of them, PQM using PLC(Power Line Communication) have good merits that can send and receive the PQ information without any new network line. This paper presents the PQM hardware and software to monitor the PQ information by using PLC that meets the categories of IEEE Std. 1159.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.9
• /
• pp.86-93
• /
• 2011

The necessity of Power Quality(PQ) Management grow bigger because the disturbance strength in power system is increasing, on the other hand, the tolerance of electrical components is reducing with widely use of the IT and digital equipments. The domestic management standards on power quality are enacted based on the IEC standards in recent. Since the IEC standards defines the measurement and evaluation point on PQ as PCC(Point of Common Coupling) which is normally the point of penetration between customer and power company, the PQ monitoring system(PQMS) should be made to measure and manage the PQ of custom effectively. In this paper, therefore, the economical construction plan on PQMS using the wireless communication channel in distribution automation system is suggested, and the usefulness of the PQMS are shown by analyzing the PQM data with IEC standards.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• v.12 no.1
• /
• pp.42-46
• /
• 2012

With the development of industry, more large-scale non-linear loads are added to existing power systems and they cause the serious power quality (PQ) problems to the nearby sensitive installations more and more. To protect the important loads and mitigate the impact of PQ disturbances on them, various compensating devices are installed. One of the most important control skills used in the compensating equipment at the load side is how fast they can recognize or detect the discontinuous abnormal PQ events from the normal voltage signal. This paper deals with two estimation methods for the fast detection and tracking of general PQ disturbances: Teager Energy Operator (TEO), which is a non-linear operator and used for a short time energy calculation, and Kalman Filter (KF), which is one of the most universally used estimation techniques. And it is also shown how to apply the TEO and the KF to detect the PQ disturbances such as voltage sag, swell, interruption, harmonics and voltage fluctuation.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.41 no.8
• /
• pp.914-916
• /
• 2016

The noise in a power signal degrades the detection rate of the power quality (PQ) event signals. We present a new wavelet de-noising technique for PQ event detection that employs the correlation-based thresholding instead of the wavelet-scale-based thresholding of existing schemes. The simulation results show that the proposed scheme is more robust to Gaussian and impulsive noisy conditions and has further improved detection ratio than existing schemes.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.8 no.6
• /
• pp.527-533
• /
• 2003

Recently, need of power stability and reliability has been increased as the spread of the sensitive electronic loads. Therefore, the power quality(PQ) problems become the hot Issue of public interest in these days. Many kinds of algorithms have been studied for the monitoring of PQ problems using the monitoring algorithms with RMS or FFT scheme, but it is still not enough to measure all of the PQ problems. This paper proposed the application of discrete wavelet transform(WT) for the PQ problems monitoring with the Introduction of WT theory, and the design of PQ monitoring data acquisition system Is described with some experimental results to verify the validity of the proposed PQ monitoring algorithm.