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With increased load demands from the customers, substation congestion problems have become inevitable to the utility companies. Instead of expanding related system installations to alleviate the short-term overloads on the facilities, feasibilities of integrating distributed generator (DG) units to defer the possible congestions are of much concern. This thesis presents an optimal location and reliability analyzing scheme for distribution system integrated with DG units, and provides the systematic guidance to utility companies for related operations. The methodology focuses on the substation capacity constraints and provides the optimal DG locations that can alleviate the congestion problem with highest reliability indices. The proposed analyzing scheme can supply valuable assistance to the utility companies and small independent power producers (IPP) for determining the installations and integrations of DG units to defer possible emerging substation expansions.

ABSTRACT i
TABLE OF CONTENTS ii
LIST OF FIGURES v
LIST OF TABLES vi
LIST OF SYMBOLS vii
1. INTRODUCTION 1
1.1 Background 1
1.2 Objectives 3
1.3 Literature review 4
1.4 Thesis outline 6
2. THE DISTRIBUTION SYSTEM 7
2.1 Basic concepts 7
2.2 Typical distribution systems 7
2.2.1 Radial distribution system 8
2.2.2 Meshed distribution system 9
2.3 The distribution system for investigation 11
2.3.1 Operational assumptions 12
2.3.2 Load and line parameters 13
2.3.3 Operational concerns 15
2.3.4 Power flow analysis for the healthy system 18
2.3.5 The substation congestion problem 22
3. DISTRIBUTED GENERATION 24
3.1 DGs for investigation 24
3.1.1 Photovoltaic generation 25
3.1.2 Wind power generation 27
3.1.3 Fuel cell unit 30
3.1.4 Battery energy storage system 32
3.2 DG impacts to the distribution system 33
3.2.1 Voltage deviation 34
3.2.2 Power loss reduction 34
3.2.3 Reliability enhancement 35
3.2.4 Congestion alleviation 36
3.3 DG installation concerns 36
3.3.1 For the utility company 37
3.3.2 For the independent power producer 38
4. OPTIMAL LOCATION FOR DG INSTALLATION 39
4.1 Problem formulation 39
4.1.1 Objective function 39
4.1.2 Operational constraints 41
4.2 Primal-Dual Interior Point Method 41
4.2.1 Searching algorithm 42
4.2.2 Implementation procedure 45
4.3 Optimal DG location 47
5. SCHEDULING FOR DG INTEGRATION 50
5.1 Reliability background 51
5.2 System reliability assessments 53
5.2.1 Reliability indices 55
5.2.2 System reliability without DG 57
5.2.3 System reliability with DG 60
5.3 System performance improvement with DG integration 65
5.3.1 Problem formulation 65
5.3.2 Reliability enhancement criteria 65
5.3.3 Congestion alleviation criteria 66
5.4 Scheduling guidance 67
5.4.1 Selection of DG 67
5.4.2 Realization implementation 68
6. CONCLUSIONS 72
REFERENCES 74
BIOGRAPHY 76

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