• Title/Summary/Keyword: Distributed Generations

Search Result 134, Processing Time 0.03 seconds

Droop Control to Compensate Load Voltage Unbalance for Inverter-based Distributed Generations with Unequal Impedance Lines (불균등 임피던스 선로를 갖는 인버터기반 분산전원의 부하전압 불평형을 보상하는 드룹 제어)

  • Yang, Won-Mo;Kim, Hyun-Jun;Han, Byung-Moon
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.65 no.7
    • /
    • pp.1193-1203
    • /
    • 2016
  • This paper proposes a droop control scheme to compensate the unbalanced line-to-line voltage of unbalanced 3-phase load which is coupled with two inverter-based distributed generations through unequal impedance lines. Unbalanced line-to-line load voltages occur due to using single-phase loads, which brings about bad effects on the coupled inverters and the distributed generations. In order to compensate the unbalanced line-to-line voltages, a positive sequence voltage control was used for sharing the active and reactive power and a negative sequence control was used for reducing the negative sequence voltage. The feasibility of the proposed scheme was first verified by computer simulations, and then experiments with a hardware set-up built in the lab. The experimental results were compared with the simulation results to confirm the feasibility of the proposed scheme.

The Development of an Algorithm for the Correction of Errors in the Phase Current of the Protective Relay on Distribution System Interconnected with Distributed Generations (분산전원 연계선로에서 보호계전기의 상전류 오차보정 알고리즘 개발)

  • Shin, Dong-Yeol;Yun, Donghyun;Cha, HanJu
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.62 no.11
    • /
    • pp.1604-1609
    • /
    • 2013
  • When the ground fault on the power side occurs on distribution system interconnected with distributed generations, the abnormal current is generated in the neutral conductor by the connection type and the iron core structure of transformers for the interconnection of distributed power supplies due to the unbalanced voltage of the system, and subsequently the false operation of the protective relay on the load side occurs. Herein, this paper proposes the method to correct errors in the phase current to prevent the false operation of the protective relay by applying p-q theory and presents the simulation result of the error correction algorithm using PSCAD/EMTDC.

Harmony Search Algorithm for Optimal Placement Problem of Distributed Generations (분산전원 최적설치를 위한 Harmony Search 알고리즘 응용)

  • Rhee, Sang-Bong;Kim, Kyu-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.59 no.5
    • /
    • pp.866-870
    • /
    • 2010
  • This paper presents a application of Harmony Search (HS) algorithm for optimal placement of distributed generations(DGs) in distribution systems. In optimization procedure, the HS algorithm denotes the searching ability for the global optimal solution with simple coding of the iteration procedure, and shows the fast convergence characteristics for getting solutions. The HS algorithm is tested on 9 buses and 69 buses distribution systems, and the results prove its effectiveness to determine appropriate placement points of DGs and reducing amount of active power without the occurrence of any mis-determination in selection of its capacity.

Performance Analysis of a Sliding Mode Control for Distributed Generations

  • Islam, Gazi;Al-Durra, Ahmed;Muyeen, S.M.;Caruna, Cedric;Tamura, Junji
    • Journal of international Conference on Electrical Machines and Systems
    • /
    • v.3 no.1
    • /
    • pp.98-104
    • /
    • 2014
  • This paper presents the performance analysis of a sliding mode based hybrid controller for three phase voltage source inverter. The main objective of this analysis is to observe the effectiveness of the controller for fault ride through (FRT) capability improvement of the distributed generations (DG). The performance of the conventional PI based cascaded controller is also presented for comparison purpose.

A Comparative Study on Value Orientation about Family Life between the Older Generations and College Students. (기성세대와 대학생의 가족생활에 대한 가치의식 비교연구)

  • 김일명
    • Journal of Families and Better Life
    • /
    • v.7 no.1
    • /
    • pp.59-78
    • /
    • 1989
  • The purpose of this study is to clarify the value orientation about family life between the older generations and college student. For this purpose, questionnaire were distributed to the older generations and college students in Seoul. Among them 920 data were obtained To obtain the family value scale, item analysis through pearson's correlation and factor analysis were used in pretest, frequency distribution, percentile, mean , t-test , and step-wise multiple were used for data analysis. The results are summarized as follows. 1) Male college students show traditional tendency and female college students show modern tendency especially sex-role attitude, ancestor worship attitude, patriarchy attitude. 2) Male and female of the older generations how traditional tendency. 3) The older generations show traditional tendency, college students show modern tendency, especially sex-role attitude and kinship attitude. 4) Male adults and male college students show traditional tendency. 5) Female adults show traditional tendency , female college students show modern tendency. In female, generation gap is more serious than males. 6) the most influencial socio-demographic variables on family value consciousness of the older generations are the religion and education, In case of college students, sex, major, religion, family income grown-up area effect on their value consciousness about family life, Based on the above findings , we should develop school education and many social programs to reduce the generation gap.

  • PDF

Optimal Placement of Distributed Generations Considering System Losses and State Estimation in Composite Distribution Systems (복합배전계통에서 계통손실을 고려한 분산형 전원의 위치선정 및 상태추정)

  • Kwon Hyung-Seok;Kim Hongrae
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.5 no.6
    • /
    • pp.533-538
    • /
    • 2004
  • Recently, it is increasing the concern of distributed generations(DGs) that installed small power at a site near by the customer. In deregulation environment, not only distributed generation operation but also state estimation is the key function in distribution systems. This paper process to calculate the impact of distributed generation on a distribution feeder. WLAV state estimation is performed the distribution systems with DGs and bad data test including single, multiple, interacting. Simulations with test cases are performed and the results are presented, using IEEE 34 bus radial distribution systems

  • PDF

The Study on Protective Coordination of Utility Interconnected Multiple Distributed Generations (다수 분산전원 연계시 계통측 보호협조에 관한 연구)

  • Jung, Seung-Bock;Kim, Jae-Chul;Lee, Bong-Yi
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
    • /
    • 2004.11a
    • /
    • pp.233-235
    • /
    • 2004
  • This paper studies protective coordination of utility interconnected multiple distirbuted generations(DG). The study of protective coordination interconnected DG has been conducted. A protective coordination of utility disturbed by reverse current of DG. Therefore, A protetive device is not operate when reverse current flows. In this paper, we use phase difference between V and I. Also, we studied protective coordination algorithm of utility interconnected multiple DG.

  • PDF

Voltage Control of ULTC and Distributed Generations in Distribution System (분산전원이 연계된 배전계통에서 ULTC와 분산전원의 전압제어)

  • Jeon, Jae-Geun;Won, Dong-Jun;Kim, Tae-Hyun
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.60 no.12
    • /
    • pp.2206-2214
    • /
    • 2011
  • LDC(Line Drop Compensation) is widely used in controlling ULTC(Under Load Tap Changer) output voltage at distribution substation. However, LDC may experience some difficulties in voltage control due to renewable energy resources and distributed generations. Therefore, more advanced voltage control algorithm is necessary to deal with these problems. In this paper, a modified voltage control algorithm for ULTC and DG is suggested. ULTC is operated with the voltages measured at various points in distribution system and prevents overvoltage and undervoltage in the distribution feeders. Reactive power controller in DG compensates the voltage drop in each distribution feeders. By these algorithms, the voltage unbalance between feeders and voltage limit violation will be reduced and the voltage profile in each feeder will become more flat.

Load Flow Analysis for Distribution Systems Including Distributed Generations (분산형 전원을 포함하는 배전계통을 위한 조류계산 기법 연구)

  • Kwon, Hyung-Seok
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.19 no.2
    • /
    • pp.100-106
    • /
    • 2005
  • This paper addressed the issue of the three-phase load flow program for electric power distribution systems that include distributed generations. The equipment models were selected in order to consider imbalances among phases for the load flow analysis of distribution systems. Also, power equations and measurement functions are newly derived. The load flow analysis program developed in this paper was tested for the propriety of algorithm and convergence characteristics by case studies on test systems in various scales and types.

Assessment of the Protection Algorithm Applied in Distributed Generations for Faults Occurred in the Interconnected Distribution Networks (외부 배전선 사고에 대한 분산전원 보호 알고리즘의 동작 수준 평가)

  • Jang, S.I.;Kim, S.G.;Park, Y.U.;Kim, K.H.;Choi, J.H.
    • Proceedings of the KIEE Conference
    • /
    • 2003.11a
    • /
    • pp.337-340
    • /
    • 2003
  • This paper describes the operational characteristics of protection algorithm applied in distributed generations(DG) for faults occurred in the interconnected distribution networks. The DG can be Influenced by abnormal grid conditions such as disturbances occurring in the neighboring distribution feeders as well as the interconnected power line. Particularly, in case of the fault happening in the neighboring distribution feeders emanated from the substation to which DG is connected, the protective devices in the DG might mis-operate. The mis-operation of protective devices can be varied by the fault conditions. The simulation results for Hoenggye substation model composed of five feeders using PSCAD/EMTDC showed that the number of mis-operation of protective devices applied in DG is about 0.66 times per one year.

  • PDF