Download SMES Modeling Performance Analysis Michael

SMES Modeling and Simulation
Benchmarking
Paulo F.Ribeiro
Calvin College / BWX Technologies, Inc
July 2001
Outline
SMES Coil Modeling
Chopper / SMES Coil Transient Interaction
Chopper Modeling + Coil
Inverter + Chopper Modeling + Coil Modeling
Integrated Energy Storage/Power Electronics/ Supply System
Integrated System: Performance / Site Sensitivity
Integrated System: CAPS Facility - STATCOM Impact
Observations
Conclusions
July 2001
Overall System Perspective
AC
Line
Transformer
Power Conversion
System CSC
or
VSC + dc-dc
chopper
Bypas
sSwitch
Dewar
Coil
ICoil
VCoil
Cryogenic
System
Controller
July 2001
Coil Protection
Coil Modeling - Parameters Computation
L   0 RN 2 (ln(
8R
 2) ,
R1
1
b2
a2
a2
b2
2b
a 2a
b 25
ln R1  ln( a 2  b 2 ) 
ln(
1

)

ln(
1

)  tan 1 
tan 1 
2
2
2
2
2
12a
b
12b
a
3a
b 3b
a 12
C
 0 r A
d
d
2
2
M 1 2   0 ( R1 R2 )[(  k ) K (k )  E (k )]
k
k
4 R1 R 2
k
( R1  R2 ) 2  d 2
July 2001
Coil Modeling - Assumptions
The dielectric constant of the insulating material does not vary with
frequency
The thermal enclosure and the tank does not carry current, and they were
represented as ground plane
 A small value of resistor represents skin effect and eddy current losses.
Parallel plate model is employed to calculate ground and series
capacitances of each turn.
To reduce the computing cost, each double pancake (two single
pancakes) is represented by its series inductance, capacitance, mutual
inductance and ground capacitances.
July 2001
Coil Modeling - Matrix Organization
1
N
2
Cg
Cad
1
Cax
2
Nsp
Cad
Cax
Cg
N
Nsp
= Capacitance between adjacent turns within a disk coil
= Capacitance between axially separated turns
= Capacitance between a turn and ground
= number of turns in a single pancake
= Number of single pancakes in a coil
July 2001
ANxN B NxN C NxN .. .. .. .. .. .. .. LNxN 
B 

 NxN ANxN B NxN .. .. .. .. .. .. .. K NxN 
C NxN B NxN ANxN .. .. .. .. .. .. .. J NxN 

DNxN C NxN BNxN .. .. .. .. .. .. .. I NxN 

Lturn 
E NxN D NxN C NxN .. .. .. .. .. .. .. H NxN 


.... .....................................................................................
.... .....................................................................................


LNxN K NxN J NxN .. .. .. .. .. .. .. ANxN  NNsxNNs
 sum( ABAB )
 sum(CBCD )

Ldb   sum( EDEF )

...................
 sum( KJKL)
sum(CBCD ) .................... sum( KJKL) 
sum( ABAB ) .................... .................... 
sum(CBCD ) .................... .................... 

.................... .................... .................... 
.................... .................... sum( ABAB )  2 Nsx 2 Ns
Coil Modeling
Cax1
Cax2
Cad1
Cad2
CadN-1
CadN-1
Cad2
Cad1
CaxN
Cad1
CadN--2 CadN-1
CaxN
Ca-2
1st Single Pancake
Cax1
2nd Single Pancake
1st Double Pancake
Cad1
Cad2
CadN-1
CadN-1
a1
a1
a1
a1
a1
a2
a2
a2
a2
aN-1
aN
Cad2
a1
aN-1
b2
b1
b1
3rd Single Pancake
Cad1
a1
Cad1
bN
CadN-2
CadN-1
a1
a1
bN-1 bN-1 bN-1
a2
aN-1
b1
b1
b1
b1
July 2001
Coil Simulation
Frequency Response
Initial Voltage Distribution
July 2001
Chopper Modeling + Coil
Transient Analysis and Protection
July 2001
Chopper Modeling + Coil
Transient Analysis and Protection
Transients under Normal Operation Condition
July 2001
Inverter + Chopper Modeling + Coil Modeling
Basic Controls
Have been developed
Controls is a major task in
order to guarantee optimum
performance (for the
several demonstration
functions) and avoid
negative power quality
impact on the supply
system
July 2001
Utility / Shipboard Supply System Considerations
July 2001
Integrated Energy Storage/Power Electronics/ Supply System
July 2001
Integrated System: Performance / Site Sensitivity
SMES Close to Load Center
SMES Close to Generation
July 2001
Observations
The performance of an integrated STATCOM + SMES, and its dynamic response to
system oscillations can be well observed and accurately determined by proper modeling
and simulation using adequate EMTP Type programs.
It has been observed that energy storage can enhance the performance of a STACOM
and possibly reduce the MVA ratings requirements of the STACOM operating alone.
This is an important finding for cost/ benefit analysis of FACTS / Power Quality devices.
Also the combination of other FACTS / Power Electronics Devices should be investigated
in order to increase performance and reduce cost.
It has been also verified that a Voltage Source Inverter / STATCOM provides a real
power flow path for SMES and that the SMES Coil chopper-controller can be controlled
independently of the STATCOM controller.
It was also observed that the location where the combined compensator is connected is
important for improvement of the overall system dynamic performance. Although the
use of a reactive power controller seems more effective in a load area, this simulation
study shows that a STATCOM with real power capability can damp the power system
oscillations more effectively, and therefore stabilize the system faster if the STATCOM SMES controller is located near a generation area rather than a load area.
July 2001
Conclusions
• The development and implementation models for the simulation of high power
electronics devices and associated energy storage systems such as a Superconducting
Magnetic Energy Storage (SMES) system (SMES Coil and DC-DC Chopper) have
been performed. Additional studies and verifications are required for better validation
of benchmarking models
• The models/simulations are intended to provide a basis for verifying performance and
developing functional specifications for the power electronics devices and associated
interfaces subsystems.
• Power electronics devices topologies, technologies, protection and control strategies
will be discussed and evaluated for its optimum performance on a specific location.
• EMTP and Dynamic Stability programs are required for the proper modeling and
simulation of a SMES system for utility application.
July 2001