china-us s&t strategic policy workshop on smart grid
TRANSCRIPT
China-US S&T Strategic Policy Workshop on Smart Grid
Yingduo Han, Chao Lu Dept. of EE, Tsinghua Univ. 5/30/2013, Washington DC
Analyses and Control of the Bulk Power System based on Synchronized Phasor Measurement System
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China-US S&T Strategic Policy Workshop on Smart Grid
Outlines
PMU/WAMS Developments
Two Typical Applications based PMU/WAMS
Roadmap and Future Work about PMU/WAMS Applications
New Thoughts based on Smart Grid Concepts
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China-US S&T Strategic Policy Workshop on Smart Grid
1. Current PMU Locations and Plan in North American
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China-US S&T Strategic Policy Workshop on Smart Grid
• PMUs were installed in more than 1500 substations and power plans. (12/12)
• WAMS master stations are deployed in all provincial dispatch centers (>40).
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Northwest:272
Northeast:291
Central:341
North:312
East:147
PMU/WAMS Deployed in China
China-US S&T Strategic Policy Workshop on Smart Grid
PMU/WAMS based Applications in China
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Angle/frequency/voltage/flow monitoring
Wide-area Monitoring
Stability Alarming
Decision Support
Advanced Control & Protection
Frequency regulation monitoring
Oscillation detection
Offline disturbance analysis
Disturbance detection
Oscillation identification and alarming
Voltage/angle/frequency trending and Stability alarming
Wide-area visualization
Improved or linear state estimation
Online model & parameter identification
Steady state stability assessment and decision optimization
Oscillation related power flow optimization
Advanced remedial actions and protections
Wide-area Damping control
Oscillation source control
Transient stability assessment and optimization
Planned system separation
Transient/voltage stability coordinated control
Renewable energy integration wide-area control
Technical challenging
China-US S&T Strategic Policy Workshop on Smart Grid
Case 1: Northeast China Power System Large Disturbances Field Tests (2003)
6 2008-9-8
500kV substation bus, artificial three-phase
grounding short circuit
China-US S&T Strategic Policy Workshop on Smart Grid
Simulation Model and Parameter Modification according to PMU Recordings
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Load Model and Parameters
Group 1 Group 2 Group 3 Group 4
East HLJ Power Transfer Limit(MW)
615 1200 1205 1210
HLJ to JL Limit (MW)
843 1236 1476 1387
JL to LN Limit (MW)
1500 1968 1985 1750
Group 1:50% constant impedance+50% motor Group 2:40% constant impedance+60% constant power
Group:the motor stator impedance is changed from 0.295 to 0.12 Group 4:IEEE-6 type motor
China-US S&T Strategic Policy Workshop on Smart Grid
Online Dominant Load Parameters Identification
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Dominant parameter selection State equation
to Volterra model
K-L orthogonal transform
Pattern classification
Steady state measurement
Dynamic state measurement
Reduced order Volterra model
based LS
Online fast pattern
recognition
Online analysis
and control
offline
online
Eigenvector matrix
Projection direction and classification
boundary
Model Para.
China-US S&T Strategic Policy Workshop on Smart Grid
Case 2: Wide-area Close Loop Damping Control in China Southern Power Grid
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• The Chinese power grid includes about 30 provincial systems, and most of them are connected through 500kV AC lines.
• After region grids interconnection, the weakly damped low frequency oscillation becomes the bottleneck of improving system transfer capacity. Increasing the PSSs can not solve this problem substantially.
The oscillation lasted 3 minutes, and the amplitude reached
120MW. (China Southern Power Grid, 8.25.2008)
The oscillation lasted 5 minutes, and the amplitude reached 730MW. (Middle
China Power Grid, 10.29.2005)
China-US S&T Strategic Policy Workshop on Smart Grid
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Mode 1
Mode 2
Key issues: 1. AC/DC interconnected system damping control strategies; 2. Wide-area controller structure design; 3. Multiple damping controllers coordination; 4. Time delay induced new oscillation modes analysis; 5. Wide-area random time delay adaptive compenstation.
GPS/Beidou
China-US S&T Strategic Policy Workshop on Smart Grid
Close Loop Time Delay Distributions
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Mean value: 67.03ms
More than 98.7% is distributed in the range of 60~75ms.
The delay is mainly composed by phasor measurement and
calculation(≈30ms), signal transmission
(≈20ms) and calculation in the
main station (≈10ms).
• PMU—Control center —Control substation, transmission distance: >2000km
• Multiple 2M channels and UDP protocol were used to reduce delay.
Time Delay (ms)
Co
un
ts in 2
ho
urs
China-US S&T Strategic Policy Workshop on Smart Grid
Time Delay induced New Oscillation Mode
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Frequency: 5~6Hz
Time delay: 50~60ms
Gain: K=5 Active
po
wer o
n th
e 5
00kV
line
(MW
)
Time (seconds)
China-US S&T Strategic Policy Workshop on Smart Grid
RTDS Tests
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PMU cubicles
Control substation cubicles
Practical HVDC pole/station control/protection cubicles
Power Amplifi
er
RTDS(10 Racks)
China-US S&T Strategic Policy Workshop on Smart Grid
Large Disturbances Field Tests Results
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• Disturbances: multiple HVDC monopole blocks (700MW), 500kV key inter-area tie-line tripping and closing;
• The damping ratio can be improved from 7.5% to 20.5%, and the transfer power limit can be enhanced more than 650MW.
5 6 7 8 9 10 11 12-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
3
3.5
时间(s)
贵州—云南相对功角(度)
高肇直流协调控制投入
高肇、 兴安直流协调控制投入
协调控制退出
0 1 2 3 4 5 6 7 8 9 10-470
-460
-450
-440
-430
-420
-410
-400
时间(秒)梧罗线功率(
MW)
高肇调制控制单独投入
协调控制系统投入
协调控制系统退出
With WHDC
Without WHDC
Mode 1
Modes 1&2
Time (seconds)
Rela
tive a
ng
le b
etw
een
Yu
nan
an
d G
uizh
ou
Active
po
wer o
n th
e 5
00kV
line (M
W)
China-US S&T Strategic Policy Workshop on Smart Grid
Our Group’s Roadmap Developing new EMS based on PMU/WAMS
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•PMU algorithm and device R&D
•WAMS framework design and system Implementation
•Wide-area damping control system
•Dominant load parameters identification ……
1993-2012
• Wide-area EMS framework design
• Power system state measurement
• New excitation and identification device
2013
• Multiple levels load identification
• Typical W-EMS application demonstration
• W-EMS experimental platform based on fast simulation
2014
•Complete W-EMS system implementation including dynamic power flow, important parameters or reduced-order system identification, steady and dynamic stability assessment and alarming, real time decision and close-loop control, all based on improved PMU/WAMS or AMI
2015-
China-US S&T Strategic Policy Workshop on Smart Grid
New Thoughts from the Smart Grid Concepts
• Traditionally, the power balance is highly dependent on the spinning reserve, and the redundancy may cause huge wastes. If the information and demanding responses are fully invloved, the power system design and operation will be changed completely.
• The information can be delivered in nearly real time (ms), so the constraints about unobservability and uncontrollability can be relaxed, and then the conventional local or “trial-and-error” controllers can be all redesigned.
• In addition, with the employment of identification techniques, the problems of randomness and time-varying characteristics of some important power system parameters can be solved. The cost of increasing conservativeness for more reliability may be saved.
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China-US S&T Strategic Policy Workshop on Smart Grid
Future Trends about PMU/WAMS • Smart grid development will accelerate PMU/WAMS
applications;
• Dynamic state estimation based on more reliable and precise PMU/WAMS will be the foundation for new generation of EMS;
• Power system model and parameters can be identified and calibrated online in the near future;
• Innovative power system measurement, identification, analysis and control theory can be developed based on emerging information technologies applications.
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