Frankfurt (Germany), 6-9 June 2011 Pyeongik Hwang School of Electrical Engineering Seoul National University Korea Hwang – Korea – RIF Session 4a – 0324 A control method of distributed generators in smart distribution system considering system loss and voltage
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Pyeongik Hwang School of Electrical Engineering Seoul National University Korea
A control method of distributed generators in smart distribution system considering system loss and voltage. Pyeongik Hwang School of Electrical Engineering Seoul National University Korea. Hwang – Korea – RIF Session 4a – 0324. Introduction. - PowerPoint PPT Presentation
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Frankfurt (Germany), 6-9 June 2011
Pyeongik Hwang
School of Electrical Engineering
Seoul National University
Korea
Hwang – Korea – RIF Session 4a – 0324
A control method of distributed generators in smart distribution system
considering system loss and voltage
Frankfurt (Germany), 6-9 June 2011
Increased installation of distributed generations(DGs) The characteristics of the distribution system is changed
Voltage profile, system loss, power flow, etc.
Introduction of the smart distribution system The status of the distribution system can be measured and
calculated more accurately The power output of DGs can be controlled using the
communication infrastructures.
Chance to more effective operation using DGsChance to more effective operation using DGs
Hwang – Korea – RIF Session 4a – 0324
Introduction
Frankfurt (Germany), 6-9 June 2011
The objectives of the proposed method Minimize the system loss Maintain the system voltage within its limit
- Minimize
- Subject to
Hwang – Korea – RIF Session 4a – 0324
DG control problem formulation
) ,(
maxnDG,
min
maxmDG,
min
maxl
min
nn
mm
lDGsDGsl
QQQ
PPP
VQPVV
) ,( DGsDGsloss QPP
Frankfurt (Germany), 6-9 June 2011
Relationship among loss, voltage, and output of DGs is highly non-linear Formulated DG control problem is a non-linear optimization
problem
Sequential Linear Programming(SLP) method is adopted Optimal solution is calculated by solving series of linear
programming (LP) problem linearized at the operation point Operation point is determined at the previous iteration
Hwang – Korea – RIF Session 4a – 0324
Sequential Linear Programming
Frankfurt (Germany), 6-9 June 2011
Sub-functions of SLP LP formulation Step size adjustment Convergence test
Decision variable for LP
Hwang – Korea – RIF Session 4a – 0324
SLP application to DG control
DGs
DGs
Q
PX
Frankfurt (Germany), 6-9 June 2011
Linearized Optimization problem
-Minimize
-Subject to
Hwang – Korea – RIF Session 4a – 0324
LP formulation
X
X
QX
P
Q
V
P
VQP
V
PP
bus
bus
busbus
busbuslossloss
||||||
1max
1max
1min
1min
min1
1max
||||
||||
nDGsDGs
nDGsDGs
nDGsDGs
nDGsDGs
lnl
nll
bus
bus
busbus
busbus
QQ
PPX
QQ
PP
VV
VVX
X
QX
P
Q
V
P
VQ
V
P
V
Loss sensitivity matrixVoltage sensitivity matrixInjection power sensitivity matrix
Frankfurt (Germany), 6-9 June 2011
Differences between distribution system and transmission system Existence of mutual impedance in line parameter Unbalanced connection of DGs
Bus admittance matrix with mutual line impedance Used for calculation of loss and voltage sensitivity matrices
A : bus incidence matrix, [y] : primitive admittance matrix.
Hwang – Korea – RIF Session 4a – 0324
LP formulation
AyAY Tbus ][
Frankfurt (Germany), 6-9 June 2011
Differences between distribution system and transmission system Existence of mutual impedance in line parameter Unbalanced connection of DGs
Bus admittance matrix with mutual line impedance Used for calculation of loss and voltage sensitivity matrices
A : bus incidence matrix, [y] : primitive admittance matrix.
Hwang – Korea – RIF Session 4a – 0324
LP formulation
AyAY Tbus ][
Frankfurt (Germany), 6-9 June 2011
Injection power sensitivity matrix calculation method
Hwang – Korea – RIF Session 4a – 0324
LP formulation
A=zeros(N, M)
for i=1:1:M
switch connection topology of P(Q) controllable DG i