8/19/2019 Power System Stabilization Using Virtual Synchronous Generator

1/15

  106 陳敬燁

Power System Stabilization Using Virtua

l Synchronous Generator With AlternatingMoment of Inertia

8/19/2019 Power System Stabilization Using Virtual Synchronous Generator

2/15

synchronous generators(SGs)

! rotating inertia

"! #isturbancessu##en changes

in$ecting the %inetic

energy to the &owergri#

SoSystemis robust againstinstability 

8/19/2019 Power System Stabilization Using Virtual Synchronous Generator

3/15

 VI'UA S*+,-'.+.US G/+/'A.' S'U,U'/

swing e0uation ：

its out&ut &ower an#

fre0uency are calculate#!

Measuring the 1oltage

an# currentsignals2

** J together with D determines the timeconstant 

 H bigger time constant, slowerresponse , smaller fre0uency #e1iation(aftera change or #isturbance)

8/19/2019 Power System Stabilization Using Virtual Synchronous Generator

4/15

3A+G43A+G ,.+'. S'A/G* .5 A/'+AI+G I+/'IA 

.ne cycle of the oscillation consists of four segments

** select a large 1alue of J #uring acceleration &hases to reduce the acceleration** select  a small 1alue of J during deceleration phases to boost the deceleration.

he transients are su&&resse#

an#ω equals zero at the newequilibrium point 

.scillation will sto&

8/19/2019 Power System Stabilization Using Virtual Synchronous Generator

5/15

5i6e# 7 Alternating 7

8/19/2019 Power System Stabilization Using Virtual Synchronous Generator

6/15

88fi6e# J cannot stabilize the fre0uency 

 When changing toalternating inertia

control

 !stabilize the system"!su&&resses the fre0uency an# &ower oscillations

effecti1ely!

9am&ing factor! An ina&&ro&riate 1alue of #am&ing factor may result in a high

magnitu#e of oscillation or a sluggish res&onse"! -ere2 choosing #am&ing factor : ;

8/19/2019 Power System Stabilization Using Virtual Synchronous Generator

7/15

9am&ing factor

!  An ina&&ro&riate 1alue of #am&ing factor may result in a high magnitu#e of oscillation or a sluggish res&onse

"! -ere2 choosing #am&ing factor : ;

 We can see the system o&eratesstably 2 an# the oscillations areeliminate# by the alternating

inertia i#ea

8/19/2019 Power System Stabilization Using Virtual Synchronous Generator

8/15

SA3II* ASS/SSM/+ 3* /+/'G* 5U+,I.+ A+A*SIS

  ω 0 J [−

P in(δ−

δ 1 ) + b( cos δ−

cos δ 1 ) ]

 Ek , is the kinetic energy

 EP is the potential energy

From Fig.4 start at point a

a to b

 

ω is zero and ! " is ma#imum&resum&tion of J $ % is needed.

 Ek & % EP is ma#imum Ek is increasing, and Ep isdecreasing as ω increasesan# !" decreases

 b to c ω decreases and ! " increasesthe total energy has #ecrease#

8/19/2019 Power System Stabilization Using Virtual Synchronous Generator

9/15

89am&ing effecthis criterion #eman#s that the #eri1ati1e of theenergy function is negati1e!

 Assuming a zero #am&ing factor D

8/19/2019 Power System Stabilization Using Virtual Synchronous Generator

10/15

G'I9 SA3II* /+-A+,/M/+3* A/'+AI+G I+/'IA 

 A! '() in Parallel *ith +ther achines

 With fi6e# 72 VSG was not ableto reco1er from the fault as

shown in 5ig! "!

the alternating inertiascheme im&ro1e# the stability ofthe a#$acent machine by the e6tra #am&ing effect im&ose#on the transient energy #irectly 

8/19/2019 Power System Stabilization Using Virtual Synchronous Generator

11/15

3! '() as an -nterace /etween the () and )rid 

System with fi6e# inertia an# a zero#am&ing factor was unable toreco1er from much mil#er faults

oscillation was su&&resse# by thealternating inertia scheme2 an# these1ere transient of #c

8/19/2019 Power System Stabilization Using Virtual Synchronous Generator

12/15

/=P/'IM/+A '/SUS

 with fi6e# moment of inertia of;!>?@ %gm" an# D & "0 pu.

 When the &ower referenceincrease#2the VSG out&ut &ower followe#the &ower comman# after&assing se1ere oscillations withthe am&litu#e of " %W 

8/19/2019 Power System Stabilization Using Virtual Synchronous Generator

13/15

 with alternating J and D & "0 pu

he effecti1eness of the alternatinginertia in the smooth transition ofcurrent le1el an# re#ucing the 1oltageri&&les at the VSG terminal is ob1iousin this figure

8/19/2019 Power System Stabilization Using Virtual Synchronous Generator

14/15

o clarify the #am&ing effect of the alternating inertia scheme

 With 9: ;2 alternating inertiathe VSG can trac% the&ower reference with negligibletransients!

8/19/2019 Power System Stabilization Using Virtual Synchronous Generator

15/15

,.+,USI.+

!3y selecting a big 1alue for the moment of inertia #uring acceleration2 the haste was mitigate#2 an# on the other han#2 #uring #eceleration2 a small 1alue for inertia factor was a#o&te# to increase the #eceleration effect

"!In the case of a real synchronous machine2 this transient energy is #issi&ate# by

#am&ing terms #uring .scillations

@!,om&are# to normal #am&ing factor D, the #am&ing e6erte# by alternating inertia is consi#erably more effecti1e an# has i#entical results in any con#itions!

!Any transients can be eliminate# before a&&earing! he i#ea #oes not only stabilize the VSG unit2 but also enhances the stabilit y of other machines in the system