Post on 03-Apr-2018
transcript
TSAT-RTDS Interface - The Development of a Hybrid Simulation Tool
Xi Lin, Pouya Zadehkhost
Powertech Labs Inc.
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Presented at panel session “Challenges and solutions of interfacing techniques for EMT/TSA hybrid simulation - Industry perspectives”
2017 IEEE PES General Meeting
Jaegul Lee, Jiyoung Song, Baekkyeong Ko
KEPCO
Kyeon Hur
Yonsei University
Feature Electro-Magnetic Transients
(EMT) Phasor Domain
(TSA)
Sample Programs PSCAD, RTDS TSAT, PSS/E, PSLF
Level of details Three-phase instantaneous values
Detailed models
Phasor-domain positive sequence
Simplified dynamic models Network dynamics ignored
Size of modeled system
Varies between a few to several hundreds of buses
Often used for simulating systems with tens of thousands of buses
Common Application Any types of studies that need detailed modeling
Hardware in Loop (HIL) simulation
Bulk power system planning and operation
On-line Dynamic Security Assessment
Power System Simulation Methods
• Power system dynamics are conventionally categorized into low- and high-frequency transients
• Two groups of industrial-grade tools have been developed based on this categorization
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Conventional Simulation Methods -Challenges
• Can focus on either detailed models in small system or simplified models in large system – Increasing level of details without reducing system size can be costly
• Study interactions between system-wide events and detailed devices can be challenging, e.g. – Fault analysis in HVDC systems
– Sub-synchronous resonance studies
• A detailed model might be available only in an EMT package, e.g. – HVDC systems, renewable generators, FACTS devices, etc.
• To built a full system model for EMT simulation is challenging – While this is a common practice in TSA studies
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Hybrid Simulation
• Hybrid simulation approach addresses these challenges by using both EMT and phasor-domain simulation methods
• Advantages – Effective in analyzing impact of low-frequency oscillations on specific components and
vice-versa
– A cheaper solution for studying large systems compared to full-EMT simulation
– Takes advantage of rich modeling library available in EMT and phasor-domain simulation packages
– Perform Hardware-In-Loop simulation with a large system model
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TSAT-RTDS Interface (TRI)
• A tool for performing hybrid simulation studies – Using both TSAT from Powertech Labs and RTDS from RTDS Technologies
• TRI is developed with special focus on practical aspects – User-friendly, minimizing case setup efforts, simplifying results analysis steps etc.
• How does TRI work – TSAT simulates external system at normal time-step (e.g. 4ms)
– RTDS simulates internal system at normal time-step (e.g. 50us)
– Boundary injections are exchanged at the end of every TSAT time-step
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RTDS Time Steps
IB(t)VB(t) VB(t+2ΔT)IB(t+ΔT) IB(t+2ΔT)VB(t+ΔT)
TSAT
RTDS
TSAT Time Steps
TRI Structure
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FPGA Board TSATRTDS
Xilinx VC707 FPGA Board
(mounted on PCI Express slot of PC which runs TSAT)
RTDS Case
Internal System
Boundary 2
Boundary 3
Boundary 1
TSAT Case
External System
Boundary 2
Boundary 3
Boundary 1
Representation of External System in EMT
• Approach 1 – simple Norton (or Thevenin) Equivalent – External system is modeled as a Norton
equivalent
– Easy-to-use since TSAT automatically • calculates Thevenin impedance
• updates Norton source current
– High frequency transients of the external system are ignored • may fail when fault is applied at boundary
– A buffer zone between internal and external systems is recommended
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Z th2
Ith1
Ith2
Z th1
...
...
Inte
rnal
Sy
stem
Bu
ffe
r Zo
ne
Representation of External System in EMT (cont’d)
• Approach 2 – Frequency Dependent Network Equivalent (FDNE) – External system is modeled as a
frequency-dependent mathematical model plus Norton current source(s)
– More accurate than Norton (Thevenin) equivalent
– May not need buffer zone
– Difficult to build the FDNE • Numerical stability
• Computation burden on the EMT
• Especially difficult for multi-port (2+)
– Handling network changes in external system is challenging
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...
...Inte
rna
l Sys
tem
FDN
E M
od
el Ith1
Ith2
TRI Features
• Supports single-port and multi-port boundaries
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G
...
...
...
G
...
...
...
G
...
...
...
One-port
system
Two-port
system
TRI Features (cont’d)
• Supports both (simple) Norton Equivalent and FDNE
• Potential TSAT-RTDS Configurations
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RTDS Case
TSAT Case 1
TSAT Case 2
TSAT Case 3
TSAT Case
RTDS Case 1 RTDS Case 2
Simulation Case Setup – RTDS Side
• RTDS case is being setup as normal
• With addition of GTFPGA and TSA-Interface
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Handling data exchange
with FPGA board
Custom model
representing one
TSAT boundary
Simulation Case Setup – TSAT Side
• TSAT case is being setup as normal – Commonly used planning data
– With addition of the Hybrid Simulation data
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Provided in a
typical TSA study
Provided in hybrid
simulation study
Simulation Case Setup – TSAT Side (cont’d)
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Defining boundaries between
internal and external systems
RTDS quantities may be
monitored on TSAT side
(optional)
System Setup – Hardware
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FPGA Board mounted on PCI
Express slot
RTDS PB5 card connected to FPGA
Board through an optical fiber
Starting Hybrid Simulation
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TSAT waits during
RTDS start-up
Boundary mismatch during
RTDS start-up can be monitored
User notifies TSAT once RTDS starts-
up (may automate this step in future)
TSAT window
RTDS window
Running Hybrid Simulation
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TSAT and RTDS run simultaneously
A disturbance applied in
one tool affects the
other
TSAT window RTDS window
Case Study #1
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• IEEE 39-bus test system
• Fault applied in internal system (bus 28)
• Generator at bus 38 is monitored
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0.00
139.00
26
0.00
139.00
-107.72
-57.70
29
24.84
261.85
28
25.26
188.5028
29
6.80
309.40
7.36
-308.08
24.84
261.85
6.80
25.26
188.50
309.40
7.36
-308.08
-0.85
293.31
38
103.67
830.001
38
41
103.67
830.001
41
-118.71
-32.62
119.58
42.01
-33.40
258.76
64.97
-255.88
108.55
-374.61
-106.95
374.61
-118.71
-32.62
-33.40
108.55
-374.61
-106.95
374.61
258.76
64.97
-255.88
119.58
42.01
-11.99
-292.16
55.63
58.01
Internal system
modeled in RTDS
Case Study #1 – Generator Rotor Speed
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Case Study #1 – Generator Terminal Voltage
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Case Study #2
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• IEEE 39-bus test system with 4 ports
Case Study #2 – Generator Rotor Speed
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Case Study #1 – Generator Terminal Voltage
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Case Study #3
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• A practical case with 2189 buses and 459 generators – Two generators modeled in RTDS
– Rest of system is modeled in TSAT (2 ports)
• Contingency description – Fault is applied on TSAT-side (2 buses away from one of boundaries)
– Cleared after 0.1 seconds
• A generator close to fault is monitored
• Long time simulation test – The fault is applied and cleared every ~200 seconds
– Simulation ran for 3 hours
– TSAT simulation keeps synchronization with RTDS
• Hard real time
• Using a Intel Core i7 7700K 4.2 GHz CPU (one core is used) and 32 GB RAM
• 4ms time-step on TSAT side (50us on RTDS side)
Case Study #3 – Generator Rotor Speed
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Case Study #3 – Generator Terminal Voltage
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Summaries
• Why using hybrid simulation? – Takes advantage of both EMT and phasor-domain simulation packages
– Facilitates analyzing interactions between low- and high-frequency transients
• TSAT-RTDS Interface – Performs hybrid simulation studies using TSAT and RTDS
– Practical aspects have been one of the main objectives
– Preliminary testing demonstrated that the tool is promising
– Allows monitoring interactions that may be missed in pure EMT or pure phasor-domain simulations
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