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ESS를 이용한 저압 배전계통의 EV 수용성 향상에 관한 연구

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Alternative Title
A Study on the Hosting Capacity of EV in Low Voltage Distribution System using ESS
Abstract
The Korean government actively takes actions of the energy policy, by which the capacity of RES(Renewable Energy Resource) is to increase up to 20% of all energy sources by the year 2030. Along with the Korean government policy, Jeju Special Self-Governing Province of Korea executes a policy(so called "Carbon Free Island Jeju by 2030") of distributing 2GW of RES and converting all vehicles into EV(Electric Vehicle) by the year 2030. In Korea, the RES capacity is not only increasing but also the fast/slow charger in buildings, homes, and public places are rapidly spreading. Especially as the installation of the slow charger for the EV users in the individual customer becomes dominant in the LVDS(Low Voltage Distribution System), it begins to act as a malicious load in LVDS designed according to transformer capacity. Therefore, a special caution is required to increase the inflow rate of the EV charger in the customer not to cause a low voltage in the secondary feeder as well as not to violate the capacity limit of the pole transformer. In addition, when it comes to the increase of RES capacity in the LVDS, it also needs a caution to prevent the overvoltage in the secondary feeder. Traditionally, in order to solve aforementioned problems, the first reinforcement action is to replace the pole transformer by a larger capacity, and to expand the secondary feeder. The second reinforcement action is to install pole transformers closer to EVs. However, the traditional approaches require time and high cost. Thus, it is understandable that the traditional approaches are not suitable for future electric networks. Therefore, this thesis proposes an innovative control algorithm of the ESS(Energy Storage System) that is to contribute to increase the capacity of EVC(Electric Vehicle Charger) in the LVDS without reinforcement of the existing facilities. An ESS is used in various forms from the transmission system to distribution system and microgrid such as frequency regulation in distribution substations, power stabilization of fluctuating RES, peak-cut for charging at light load and discharging at heavy load, and emergency power generation, etc. In particular, the introduction of the ESS in a LVDS without voltage regulation can have a number of advantages. However, as the capacity of EV and renewable energy is continuously increased in LVDS, research is needed to increase the capacity that can be connected using existing facilities as well as voltage issues. In the proposed control algorithm, in order to solve the problems of voltage drop/rising and feeder capacity by introducing a large number of EV chargers and RES in the LVDS, an advantage of ESS bidirectional power flow is considered at the end of the secondary feeder in order to maintain the voltage and the power within allowable limit(voltage: 220±6%, feeder capacity: pole transformer rated capacity). The proposed control algorithm shows its ability to expand the capacity of EV up to maximum twice the capacity of the pole transformer with the various conditions while the voltage and feeder capacity are maintained with allowable limit. Its ability is assessed and discussed by the simulation consisting of an ESS, PV, EVC, and load in the environment of PSCAD/EMTDC software and hardware system.
Author(s)
유경상
Issued Date
2020
Awarded Date
2020. 8
Type
Dissertation
URI
http://dcoll.jejunu.ac.kr/common/orgView/000000009548
Alternative Author(s)
Ryu, Kyung Sang
Affiliation
제주대학교 대학원
Department
대학원 에너지응용시스템학부 전기공학전공
Advisor
김호찬
Table Of Contents
LIST OF FIGURES ⅲ
LIST OF TABLES ⅶ
SUMMARY ⅹ
1. 서 론 1
1.1 논문의 배경 및 필요성 1
1.2 논문의 목표 4
1.3 논문의 구성 6
2. 복합 저압 배전계통 전압특성 분석 7
2.1 태양광전원이 연계된 배전계통의 전압특성 분석 7
2.2 EV 증가가 제주 전력계통에 미치는 영향 분석 9
2.3 EV 및 태양광전원의 수용성 향상을 위한 배전용 ESS의 도입 방안 12
3. PSCAD/EMTDC를 이용한 복합 저압 배전계통 모델링 17
3.1 EV 부하 모델링 18
3.2 태양광전원 모델링 19
3.3 ESS 모델링 23
4. EV 수용성 향상을 위한 배전용 ESS의 제어 알고리즘 29
4.1 배전용 ESS의 제어 방안 29
4.2 복합 저압 배전계통의 전압특성 분석 31
4.3 배전용 ESS의 제어 알고리즘 35
5. 시뮬레이션 및 수용성 향상 결과 분석 42
5.1 시뮬레이션 조건 42
5.2 ESS 연계 전/후의 선로용량 및 전압 특성 45
5.3 ESS의 연계지점에 따른 선로용량 및 전압 특성 59
5.4 부하분포에 따른 선로용량, 전압 특성 및 ESS 출력용량 65
5.5 ESS의 도입용량 및 경제성 분석 75
5.6 수용성 향성 분석 및 결과 고찰 78
6. 30kW급 복합배전계통 시험장치 구현 및 시험결과 분석 82
6.1 복합 저압 배전계통 시험장치 구현 82
6.2 EV 수용성 향상에 관한 검증시험 및 분석 95
7. 결 론 107
참 고 문 헌 109
감사의 글 114
Degree
Doctor
Publisher
제주대학교 대학원
Citation
유경상. (2020). ESS를 이용한 저압 배전계통의 EV 수용성 향상에 관한 연구
Appears in Collections:
Faculty of Applied Energy System > Electrical Engineering
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