• Title, Summary, Keyword: Power quality

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Smart Grid-The next Generation Electricity Grid with Power Flow Optimization and High Power Quality

  • Hu, Jiefeng;Zhu, Jianguo;Platt, Glenn
    • Journal of international Conference on Electrical Machines and Systems
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    • v.1 no.4
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    • pp.425-433
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    • 2012
  • As the demand for electric power increases rapidly and the amount of fossil fuels decreases year by year, making use of renewable resources seem very necessary. However, due to the discontinuous nature of renewable resources and the hierarchical topology of existing grids, power quality and grid stability will deteriorate as more and more distributed generations (DGs) are connected to the grids. It is a good idea to combine local utilization, local consumption, energy storage and DGs to form a grid-friendly micro grid, these micro grids can then assembled into an intelligent power system - the smart Grid. It can optimize power flow and integrate power generation and consumption effectively. Most importantly, the power quality and grid stability can be improved greatly. This paper depicts how the smart grid addresses the current issues of a power system. It also figures out the key technologies and expectations of the smart grid.

A Study on Filcker Evaluation Considering Power Quality Disturbance of Power System (전력계통의 전력품질 외란을 고려한 플리커 평가에 관한 연구)

  • Jung, Seung-Bock;Kim, Jae-Chul
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • pp.376-379
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    • 2006
  • This paper studies flicker evaluation considering power quality disturbance. A flicker problem with light device irritates human's eyes. Also, the flicker problem has an influence on adverse effect such as rolling device and rotating device. However, a study of flicker evaluation is not complete. A flicker is measured and evaluated at monitoring point. But we consider power qualify disturbances such as voltage sag and transient that cause fault and inverter/breaker switching. Power quality disturbances affects flicker evaluation. A flicker evaluation index increases. Therefore, we consider power quality disturbances. We detect voltage sag and transient using wavelet and evaluate flicker without flicker index including power quality disturbances.

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Power Quality Improvement in Autonomous Microgrids Using Multi-functional Voltage Source Inverters: A Comprehensive Review

  • Miveh, Mohammad Reza;Rahmat, Mohd Fadli;Ghadimi, Ali Asghar;Mustafa, Mohd Wazir
    • Journal of Power Electronics
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    • v.15 no.4
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    • pp.1054-1065
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    • 2015
  • Multi-functional voltage source inverters (VSIs) have attracted increasing attention in recent years for their advantageous auxiliary services for power quality enhancement in autonomous microgrids. These types of VSIs can not only achieve a proper control scheme in autonomous mode but also cope with the prescribed power quality and stability requirements. These functionalities are integrated within the same device, thereby significantly improving the cost-effectiveness of microgrids while decreasing the investment and bulk compared with those of multiple devices with independent functionalities. Control strategies for power quality enhancement in autonomous microgrids using multi-functional VSIs are comprehensively reviewed in this paper. In addition, such VSIs are discussed in detail, and comparisons of which are also provided. Lastly, a number of future research directions for multi-functional VSIs are recommended.

Analysis of Anti-Islanding Schemes using Frequency Drift in Distributed Generation System (분산전원 시스템의 주파수 변동을 통한 단독운전 방지기법 분석)

  • Jo, Yeong-Min;Cho, Sang-Yoon;Song, Seung-Ho;Choy, Ick;Choi, Ju-Yeop;Lee, Young-Kwoun
    • The Transactions of the Korean Institute of Power Electronics
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    • v.20 no.3
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    • pp.247-254
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    • 2015
  • Unintentional islanding results in safety hazards, power quality degradation, and many other issues. Thus, islanding detection of grid-connected distributed generation system is a key function for standards compliance. Many anti-islanding schemes are currently being studied; however, existing anti-islanding schemes used in inverters have power quality degradation and non-detection zone issues. Therefore, this paper analyzes existing anti-islanding schemes by using frequency drift in accordance with both islanding detection performance and power quality. This paper also proposes a new anti-islanding scheme by using frequency drift. Both simulation and experimental results show that the proposed scheme has negligible power quality degradation and no non-detection zones compared with other existing schemes.

Improved Power Quality IHQRR-BIFRED Converter Fed BLDC Motor Drive

  • Singh, Bhim;Bist, Vashist
    • Journal of Power Electronics
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    • v.13 no.2
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    • pp.256-263
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    • 2013
  • This paper presents an IHQRR (Integrated High Quality Rectifier Regulator) BIFRED (Boost Integrated Flyback Rectifier Energy Storage DC-DC) converter fed BLDC (Brushless DC) motor drive. A reduced sensor topology is derived by utilizing a BIFRED converter to operate in a dual DCM (Discontinuous Conduction Mode) thus utilizing a voltage follower approach for the PFC (Power Factor Correction) and voltage control. A new approach for speed control is proposed using a single voltage sensor. The speed of the BLDC motor drive is controlled by varying the DC link voltage of the front end converter. Moreover, fundamental frequency switching of the VSI's (Voltage Source Inverter) switches is used for the electronic commutation of the BLDC motor which reduces the switching losses in the VSI. The proposed drive is designed for a wide range of speed control with an improved power quality at the AC mains which falls within the recommended limits imposed by international power quality standards such as IEC 61000-3-2.

The Effect of Power Type within Supply Chain on the Information Capability: Perspective of CSV Value Creation (공급사슬 내의 파워유형이 정보역량에 미치는 영향: CSV 가치창출 관점)

  • Park, Kwang-O;Chang, Hwal-Sik;Jung, Dae-Hyun
    • The Journal of Information Systems
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    • v.27 no.3
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    • pp.1-24
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    • 2018
  • Purpose The purpose of this study is to attempt to incorporate power theory to evaluate information capability of SCM adopters. Therefore, this study focuses on the relationship of information sharing, partnership quality, and information capacity according to the power intensity of the variables of SCM. and CSV value creation. Design/methodology/approach The questionnaire of SCM builder was conducted and 302 samples were analyzed. Based on the theoretical background of power and information capacity, we set up a structural equation model. Hypothesis testing and statistical analysis were done through AMOS and SPSS. Findings First, it shows that the compensation power among the constrained power has a positive effect on the partnership quality, and the legitimacy power has the positive influence only on the information sharing. Compulsive power, compensation, and legitimacy, which are generally restrictive powers, may reduce the quality of information sharing and partnership, but the results of this study are rather higher. Second, both non-binding power expertise and criterion have a positive effect on information sharing and partnership quality. Third, information sharing has a positive effect on partnership quality. Supporting a number of research results, it is well reflected in SCM attributes where interdependence is important. Fourth, information sharing and partnership quality have a positive effect on information capacity. Information literacy has become an essential element in modern management. Fifth, the enhancement of CSV value creation plays a role of a controlling variable to further strengthen information sharing through non - binding power attribute, expertise and conformity. In addition, the strengthening of CSV value creation has been shown to play a role as a controlling variable to further strengthen the quality of partnership through the non-binding power attribution, but expertise has been rejected.

System Design for Real-Time Measuring of Power Quality and Harmonics Distortion using Digital Signal Processor (Digital Signal Processor를 이용한 실시간 전력 요소와 왜율 측정 시스템 설계)

  • kim, Geun-Jun;Kang, Bongsoon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.20 no.7
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    • pp.1283-1289
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    • 2016
  • Electrical energy is the essential resource for modern society. Recently, the demand for power was significantly increased. Increase of power demand has lead to a decrease in the power quality. Power quality in modern society has been an important factor that can cause a major problem throughout the home and general industry. Therefore, we need a system for preventing the power quality problems. To avoid power issues, it is important that the measurement of the power quality and initial response. In this paper, we propose real-time power quality measurement system and harmonics monitoring system. We design the system using DM240001 board include dsPIC33FJ256GP710A of microchip. This system can adapt three-phase three-wire system. And optimized the algorithm, we can measure momentary changes of the power system. In addition, designed system can measure harmonics distortion like to VTHD, ITHD and ITDD for 31th harmonics.

Control of Railway Power Quality Conditioner for AC Electrified Railway Systems (교류 전기철도 급전시스템을 위한 철도용 전기품질 보상장치의 제어방법)

  • Park, Han-Eol;Song, Joong-Ho
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.8
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    • pp.48-54
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    • 2010
  • The AC electrified railway systems have the power quality problems such as the harmonic distortion, the reactive power and the three-phase imbalance because of the electrical load characteristics of locomotives, which are non-linear single-phase. These power quality problems have a bad effect on not only AC electrified railway systems but also other electric systems connected together. The RPQC (railway power quality conditioner) can compensate such power quality problems in the AC electrified railway systems. In this paper, a novel RPQC control method based on SRF (synchronous-reference-frame) control is proposed. The proposed RPQC control method can compensate effectively the harmonic currents, the reactive power and the load imbalance. The validity and the effectiveness of the proposed RPQC control method are illustrated through the simulations.

Modelling a Stand-Alone Inverter and Comparing the Power Quality of the National Grid with Off-Grid System

  • Algaddafi, Ali;Brown, Neil;Rupert, Gammon;Al-Shahrani, Jubran
    • IEIE Transactions on Smart Processing and Computing
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    • v.5 no.1
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    • pp.35-42
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    • 2016
  • Developments in power electronics have enabled the widespread application of Pulse Width Modulation (PWM) inverters, notably for connecting renewable systems to the grid. This study demonstrates that a high-quality power can be achieved using a stand-alone inverter, whereby the comparison between the power quality of the stand-alone inverter with battery storage (off-grid) and the power quality of the utility network is presented. Multi-loop control techniques for a single phase stand-alone inverter are used. A capacitor current control is used to give active damping and enhance the transient and steady state inverter performance. A capacitor current control is cheaper than the inductor current control, where a small current sensing resistor is used. The output voltage control is used to improve the system performance and also control the output voltage. The inner control loop uses a proportional gain current controller and the outer loop is implemented using internal model control proportional-integral-derivative to ensure stability. The optimal controls are achieved by using the Sisotool tool in MATLAB/Simulink. The outcome of the control scheme of the numerical model of the stand-alone inverter has a smooth and good dynamic performance, but also a strong robustness to load variations. The numerical model of the stand-alone inverter and its power quality are presented, and the power quality is shown to meet the IEEE 519-2014. Furthermore, the power quality of the off-grid system is measured experimentally and compared with the grid power, showing power quality of off-grid system to be better than that of the utility network.

A Study of Power Quality Monitoring System Using Web Technology (웹 기술을 이용한 전기품질 감시시스템 연구)

  • Lee, K.S.;Lim, S.I.;Lee, S.J.;Lee, D.W.;Park, D.H.;Kim, J.H.
    • Proceedings of the KIEE Conference
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    • pp.148-150
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    • 2003
  • A meaning of power quality has changed, which affects on an environmental change of existing electricity supply markets. Today, it should take both consumers and suppliers into consideration to develop information and communication technology and to increase the use of power and electronic equipments. As a result, it is necessary to develop a system to monitor power quality and to display data. In this paper, a system, as a power quality monitoring equipment, which can use protective replays with progress of microprocessor technology and provide information in the intranet/internet circumstances using web-based architecture is described.

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