• Title/Summary/Keyword: Distributed Generations

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Application of Fault Location Method to Improve Protect-ability for Distributed Generations

  • Jang Sung-Il;Lee Duck-Su;Choi Jung-Hwan;Kang Yong-Cheol;Kang Sang-Hee;Kim Kwang-Ho;Park Yong-Up
    • Journal of Electrical Engineering and Technology
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    • v.1 no.2
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    • pp.137-144
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    • 2006
  • This paper proposes novel protection schemes for grid-connected distributed generation (DG) units using the fault location algorithm. The grid-connected DG would be influenced by abnormal distribution line conditions. Identification of the fault location for the distribution lines at the relaying point of DG helps solve the problems of the protection relays for DG. The proposed scheme first identifies fault locations using currents and voltages measured at DG and source impedance of distribution networks. Then the actual faulted feeder is identified, applying time-current characteristic curves (TCC) of overcurrent relay (OCR). The method considering the fault location and TCC of OCR might improve the performance of the conventional relays for DG. Test results show that the method prevents the superfluous operations of protection devices by discriminating the faulted feeder, whether it is a distribution line where DG is integrated or out of the line emanated from the substation to which the DGs are connected.

Dynamic Island Partition for Distribution System with Renewable Energy to Decrease Customer Interruption Cost

  • Zhu, Junpeng;Gu, Wei;Jiang, Ping;Song, Shan;Liu, Haitao;Liang, Huishi;Wu, Ming
    • Journal of Electrical Engineering and Technology
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    • v.12 no.6
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    • pp.2146-2156
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    • 2017
  • When a failure occurs in active distribution system, it will be isolated through the action of circuit breakers and sectionalizing switches. As a result, the network might be divided into several connected components, in which distributed generations could supply power for customers. Aimed at decreasing customer interruption cost, this paper proposes a theoretically optimal island partition model for such connected components, and a simplified but more practical model is also derived. The model aims to calculate a dynamic island partition schedule during the failure recovery time period, instead of a static islanding status. Fluctuation and stochastic characteristics of the renewable distributed generations and loads are considered, and the interruption cost functions of the loads are fitted. To solve the optimization model, a heuristic search algorithm based on the hill climbing method is proposed. The effectiveness of the proposed model and algorithm is evaluated by comparing with an existing static island partitioning model and intelligent algorithms, respectively.

The Advanced Voltage Regulation Method for ULTC in Distribution Systems with DG

  • Kim, Mi-Young;Song, Yong-Un;Kim, Kyung-Hwa
    • Journal of Electrical Engineering and Technology
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    • v.8 no.4
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    • pp.737-743
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    • 2013
  • The small-scaled onsite generators such as photovoltaic power, wind power, biomass and fuel cell belong to decarbonization techniques. In general, these generators tend to be connected to utility systems, and they are called distributed generations (DGs) compared with conventional centralized power plants. However, DGs may impact on stabilization of utility systems, which gets utility into trouble. In order to reduce utility's burdens (e.g., investment for facilities reinforcement) and accelerate DG introduction, the advanced operation algorithms under the existing utility systems are urgently needed. This paper presents the advanced voltage regulation method in power systems since the sending voltage of voltage regulators has been played a decisive role restricting maximum installable DG capacity (MaxC_DG). For the proposed voltage regulation method, the difference from existing voltage regulation method is explained and the detailed concept is introduced in this paper. MaxC_DG estimation through case studies based on Korean model network verifies the superiority of the proposed method.

A study on the Operation Algorithm for Bi-directional Sectonalizer in Distribution System Interconnected with Distributed Generations (분산전원이 연계된 배전계통의 양방향 구간개폐기의 동작 알고리즘에 관한 연구)

  • Yoon, Gi-Gab;Jeong, Jum-Soo;An, Tae-Pung;Rho, Dae-Seok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.8
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    • pp.1802-1809
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    • 2009
  • Abstract The typical distribution systems have the power flow from distribution substations (sources) to customers (load) only as one direction. However, in the case where distributed generations (DG) such as PV system and wind power systems are connected to distribution systems, the DG output variations to distribution systems, so called reverse power flow, may cause the bi-directional power flow. So, the reverse power flow has severe impacts on typical power system, for example power quality problems, protection coordination problems, and so on. Especially, protection devices (sectionalizer) in primary feeder of distribution system interconnected with distributed generations may cause problems of malfunction, and then many customers could have problems like an interruption. So, this paper presents the bi-directional operation algorithm of protection devices to overcome the problems like mal-function. And, also this paper shows the effectiveness of proposed method by using both PSCAD/EMTDC software and test facility of protection devices to simulate the field distribution systems.

Development of Monitoring System for Interconnection of Distributed Generation with Power Grid (분산전원 계통 연계를 위한 모니터링 시스템의 개발)

  • Oh, Sung-Nam;Son, Young-Ik;Kim, Kab-Il
    • Proceedings of the KIEE Conference
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    • 2004.11c
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    • pp.714-716
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    • 2004
  • Owing to the environmental problems as well as increasing energy prices and power plant construction costs, many researches have been made for the safe operation of distributed generations. In order to be more popularly used in parallel with the distribution network, the distributed generation and its correlation with the power system should be exactly monitored at any time. This paper presents a monitoring system which displays the important states of the distributed generation in operation and stores various measurements of the system. The proposed system constructs a data-base for developing algorithms against any faults of the interconnected system, and monitors efficiently at any place with the communication network function.

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An Improved Anti-Islanding Algorithm for Utility Interconnection of Multiple Distributed Fuel Cell Powered Generations

  • Jeraputra Chuttchaval;Hwang In-Ho;Choi Se-Wan;Aeloiza Eddy C.;Enjeti Prasad N.
    • Journal of Electrical Engineering and Technology
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    • v.1 no.2
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    • pp.192-199
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    • 2006
  • This paper presents an improved anti-islanding algorithm for utility interconnection of multiple distributed fuel cell powered generations (DFPGs). A cross-correlation method is proposed and implemented in conjunction with the anti-islanding algorithm developed in the previous work [I]. While the power control algorithm continuously perturbs $({\pm}5%)$ the reactive power supplied by the DFPG, the proposed algorithm calculates the cross-correlation index of a rate of change of the frequency deviation with respect to $({\pm}5%)$ the reactive power to confirm islanding. If this index is above 50%, the algorithm further initiates $({\pm}10%)$ the reactive power perturbation and continues to calculate the correlation index. If the index exceeds 80%, the occurrence of islanding can be confirmed. The proposed method is robust and capable of detecting the occurrence of islanding in the presence of several DFPGs, which are independently operating. Viability of the cross-correlation method is verified by the simulation. Experimental results are presented to support the findings of the proposed method.

An Optimal Procedure for Sizing and Siting of DGs and Smart Meters in Active Distribution Networks Considering Loss Reduction

  • Sattarpour, T.;Nazarpour, D.;Golshannavaz, S.;Siano, P.
    • Journal of Electrical Engineering and Technology
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    • v.10 no.3
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    • pp.804-811
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    • 2015
  • The presence of responsive loads in the promising active distribution networks (ADNs) would definitely affect the power system problems such as distributed generations (DGs) studies. Hence, an optimal procedure is proposed herein which takes into account the simultaneous placement of DGs and smart meters (SMs) in ADNs. SMs are taken into consideration for the sake of successful implementing of demand response programs (DRPs) such as direct load control (DLC) with end-side consumers. Seeking to power loss minimization, the optimization procedure is tackled with genetic algorithm (GA) and tested thoroughly on 69-bus distribution test system. Different scenarios including variations in the number of DG units, adaptive power factor (APF) mode for DGs to support reactive power, and individual or simultaneous placing of DGs and SMs have been established and interrogated in depth. The obtained results certify the considerable effect of DRPs and APF mode in determining the optimal size and site of DGs to be connected in ADN resulting to the lowest value of power losses as well.

An Investigation on Correction of Overcurrent Protective Relaying Set Value for Bus Interconnected with Distributed Generations (분산전원의 계통 연계에 따른 모선 보호용 과전류 계전기 설정치 정정에 대한 고찰)

  • Jang, Sung-Il;Kim, Ji-Won;Park, In-Ki;Kwon, Hyouk-Jun;Kim, Kwang-Ho
    • Proceedings of the KIEE Conference
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    • 2002.11b
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    • pp.137-140
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    • 2002
  • This paper describes the effect of distributed generations (DG) on the bus protection scheme. When the generating capacity of DG is larger than 3 MVA totally, DG are generally connected to the 22.9 kV bus directly with the dedicated line. Due to the fault current contribution of DG, the overcurrent protective relay that have conventional set value cannot detect the fault occurred in distribution power network with DG. Therefore. the impacts from interconnection of DG on the overcurrent protective relay for bus protection should be accurately assessed and mitigated. Simulation results show that it would be necessary to modify the overcurrent protective relay set value for protecting the bus according to the generating capacity of DG.

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A Study on the Over Current Relay Misoperation in Power System with Distributed Generations (분산전원 연계 계통에서의 과전류계전기 오동작에 관한 연구)

  • Park, Jong-Il;Lee, Kyebyung;Park, Chang-Hyun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.12
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    • pp.1705-1710
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    • 2018
  • This paper deals with an analysis of the causes of over current relay(OCR) misoperation in power system with distributed generations(DG). In general, Y-D and Y-Y-D transformer connections are used for grid interconnection of DG. According to the interconnection guideline, the neutral point on Y side should be grounded. However, these transformer connections can lead to OCR misoperation as well as over current ground relay(OCGR) misoperation. Several researches have addressed the OCGR misoperation due to the interaction between transformer connections and zero-sequence voltage of distribution system. Recently, a misoperation of OCR at the point of DG interconnection to the utility system has been also reported. With increasing the interconnections of DG, such OCR as well as OCGR misoperations are expected to increase. In this paper, PSCAD/EMTDC modeling including DG interconnection transformer was performed and various case studies was carried out for identifying the cause of OCR misoperation.

Environmental Damage Theory Applicable to Kenya

  • ONYANGO, James;KIANO, Elvis;SAINA, Ernest
    • Asian Journal of Business Environment
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    • v.11 no.1
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    • pp.39-50
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    • 2021
  • Purpose: This study seeks to establish the environmental damage theory applicable to Kenya. The analysis is based on annual data drawn from World Bank on carbon dioxide emissions (CO2e) and gross domestic product per capita (GDPPC) for Kenya spanning 1963 to 2017. Research Methodology: The study adopts explanatory research design and autoregressive distributed lag model for analysis. Results: The results revealed a coefficient of -0.017 for GDPPC and 0.004 for GDPPC squared indicating that economic growth has negative effect on CO2e in the initial stages of growth but positive effect in the high growth regime with the marginal effect being higher in the initial growth regime. The findings suggest a U-shaped relationship consistent with Brundtland Curve Hypothesis (BCH). Conclusions: The findings emphasize the need for sustainable development path that enables present generations to meet own needs without compromising the capacity of future generations to meet their own. Sustainable development may include, investment in renewable energies like wind, solar and adoption of energy efficient technologies in production and manufacturing. The study concludes that BCH is applicable to Kenya and that developing affordable and effective mechanisms to boost sustainable development implementation is necessary to decrease the anthropogenic impact in the environment without any attendant reduction in the economic growth.