10th Annual University of Pittsburgh
Electric Power Industry Conference
“System Studies for Grid Level Integration of
Power Electronic Devices”
Presentation
November 16, 2015
1:30 PM Session
Adam R. Sparacino
System Studies Engineer
POWER SYSTEMS ENGINEERING SERVICES (PSES)
1
Outline of Presentation
•
•
Introduction to Power System Engineering Services Department
Studies for Power Electronics Installations
POWER SYSTEMS ENGINEERING SERVICES (PSES)
2
Introduction to Power Systems
Engineering Systems Department
POWER SYSTEMS ENGINEERING SERVICES (PSES)
3
Power System Engineering Services Department
•
•
17 full-time employees
Three remote offices
– Albany, NY
– Galveston, TX
– Pomona, CA
•
Three Specialty Teams
– Power Electronics Team (New Technology Support)
– Transients Team (Equipment/Apparatus/Substations Support)
– Stability Team (Operations/Planning Support)
POWER SYSTEMS ENGINEERING SERVICES (PSES)
4
Scope of Experience
•
•
•
•
•
Nationwide utility and industrial applications
Voltages ranging from 800kV to 120V (200+mi lines to 0.5ft cable)
Steady-state to microsecond timeframes
Software: PSS/E, PSLF, PowerGem TARA, PSCAD, EMTP-RV, MATLAB,
CDEGS, ASPEN, Python, E-Tran
Active participation in industry organizations such as IEEE, CIGRE, WECC,
NYISO, SPP, ERCOT, PJM
POWER SYSTEMS ENGINEERING SERVICES (PSES)
5
Reasons for Performing Studies
•
•
•
•
•
•
•
Ensure compliance with ANSI/IEEE Standards
Ensure compliance with regional operating criteria and specific operating
procedures, philosophy, and safety/maintenance standards
Ensure equipment suited for application of interest
Review/confirmation of results and recommendations
Balance work-loads
Re-visit procedures under new system conditions
Perform discovery-type work on advanced system topics
POWER SYSTEMS ENGINEERING SERVICES (PSES)
6
Key Studies for SVC (Static Var Compensator)
Installations
POWER SYSTEMS ENGINEERING SERVICES (PSES)
7
Example One-Line of SVC
POWER SYSTEMS ENGINEERING SERVICES (PSES)
8
General Studies for Design and Validation of SVC Equipment
• Harmonic Impedance Analysis
– Determine range of possible system impedances for use in design and rating of
SVC equipment
• Step Test Analysis
– Determine settings of controller gains such that the SVC operates quickly
enough and remains stable for desired range of system strength.
• Electromagnetic transients and insulation coordination analysis
– Determine the maximum voltage and current stresses for all possible system
operating conditions.
• Dynamic Performance Analysis
– Verify that the SVC operates as intended in response to major system
disturbances and that no adverse interaction exists between nearby power
system equipment.
• Interaction Studies (special - as needed)
POWER SYSTEMS ENGINEERING SERVICES (PSES)
9
Harmonic Impedance Sectors
• AC filter design for an SVC is influenced by the harmonic impedance of the
system.
• Calculate harmonic impedance sectors
– Examine different loading conditions
– Examine various operating conditions
f‐Z Harmonic Impedance
6000
5000
Z (Ohms)
4000
3000
2000
1000
0
0
250
500
750
1000
1250
1500
1750
2000
2250
2500
2750
3000
Frequency (Hz)
POWER SYSTEMS ENGINEERING SERVICES (PSES)
SPR_A001
SPR_A002
SPR_A003
SPR_A004
SPR_C001
SPR_C002
SPR_C003
SPR_C004
SPR_D001
SPR_D002
SPR_D003
SPR_D004
SUM_A001
SUM_A002
SUM_A003
SUM_A004
SUM_C001
SUM_C002
SUM_C003
SUM_C004
SUM_D001
SUM_D002
SUM_D003
SUM_D004
10
Harmonic Impedances Sectors
POWER SYSTEMS ENGINEERING SERVICES (PSES)
11
Harmonic Performance and Equipment Rating Analysis
•
Results from the harmonic impedance analysis are included in the design of
the SVC.
– Verify the harmonic performance of the SVC equipment design
– Incorporate harmonic impedance sectors, measurement data ,and TCR
harmonic currents
POWER SYSTEMS ENGINEERING SERVICES (PSES)
12
Subsynchronous Torsional Interaction Analysis
•
Turbine generators have torsional modes of oscillation.
–
–
•
Torsional stress caused by:
–
–
•
•
•
•
Steam turbines have the least mechanical damping (Dm), especially at light load.
Gas turbines have higher Dm
Impact loading: faults, switching, trips
Unstable torsional interactions with the system (SSR, SSTI)
Sub-synchronous torsional modes (mechanical), below 60 Hz, of a generator can
interact with the electrical system to which the generator is connected and result in
torsional oscillations that are self sustaining or growing. These oscillations can lead
to unstable conditions and can be damaging to the generator shaft system.
Sub-synchronous torsional interactions can be identified by examining the electrical
damping torque per unit of generator velocity.
Positive electrical damping indicates that the electrical system will help to stabilize
torsional oscillations and negative electrical damping indicates the electrical system
will tend to destabilize torsional oscillations.
A perturbation analysis can be used to identify sub-synchronous generator
oscillations that could result in destabilizing electrical damping.
POWER SYSTEMS ENGINEERING SERVICES (PSES)
13
Illustration of the Perturbation Method
Multi-mass
Interface
Generator
Transformer
Transmission
Line
Series
Compensation
Transmission
System
SVC
Perturbation
Input Signal
(ω)
Observed Resulting
Electrical Torque
(Te)
POWER SYSTEMS ENGINEERING SERVICES (PSES)
 T 
Damping  Real e 
  
14
Electrical Damping With and Without SVC
N-6 Condition Cases
8.00E‐03
Electrical Damping (p.u./rad/sec)
6.00E‐03
4.00E‐03
No SVC
The addition of the SVC
has a negligible effect on
the negative component
of electrical damping.
SVC 0 Mvar Output
SVC 70 Mvar Output
SVC 200 Mvar Output
2.00E‐03
SVC ‐100 Mvar Output
0.00E+00
5
10
15
20
‐2.00E‐03
POWER SYSTEMS ENGINEERING SERVICES (PSES)
25
30
35
40
45
50
55
Mechanical Frequency (Hz)
15
Dynamic Performance Analysis
• Verify that the SVC controls the system dynamic performance during system
disturbances such as major faults
– 5 to 20 seconds time-frame (PSLF/PSSE)
– SVSMO1U1 model
– Examine different loading conditions
– Examine various operating conditions
•
Can be performed in pre-bid stage to assist in rating and placement of
FACTS device.
POWER SYSTEMS ENGINEERING SERVICES (PSES)
16
Dynamic Performance Analysis Results
Voltage at SVC bus in response to a 3LG fault at a remote bus
Without SVC
With SVC
POWER SYSTEMS ENGINEERING SERVICES (PSES)
17
Dynamic Performance Analysis Results
SVC output in response to a 3LG fault at a remote bus
SVC Ordered Output - B
SVC Measured Output - Q
POWER SYSTEMS ENGINEERING SERVICES (PSES)
18
Thank You for Your Attention
POWER SYSTEMS ENGINEERING SERVICES (PSES)
19