The Structure and Operation of CSG Integrated Low ... · The Structure and Operation of CSG...
Transcript of The Structure and Operation of CSG Integrated Low ... · The Structure and Operation of CSG...
The Structure and Operation of CSG Integrated
Low Frequency Oscillation Defense System
Liang Zhifei, Xiao Ming, Zhang Kun
CSG Power Dispatching Control Centre, Guangzhou, China
Outline
I. Introduction
II. The dynamic stability situation in CSG
III. The structure of Integrated Low Frequency Oscillation Defense System
IV. Discussion of Improving the Defense Line
V. Conclusion
I. Introduction
China Southern Power Grid (CSG) is a typical power grid with ultra-high voltage level,
long-distance transmissions, large capacity and hybrid AC/DC operation mode. Since its
establishment in 2002, CSG started to face a complicated dynamic stability problem
represented by low frequency oscillation. Since 2005, dynamic problem became the
threshold of transmitting electricity from the western areas to East China
This paper reviewed current dynamic stability situation in CSG, introduce the structure
and operation experiences of CSG integrated low frequency oscillation defense system,
give out success application cases in 2010 and 2011. Finally suggestions for improving
the performance of present defense system are proposed.
Outline
I. Introduction
II. The dynamic stability situation in CSG
III. The structure of Integrated Low Frequency Oscillation Defense System
IV. Discussion of Improving the Defense Line
V. Conclusion
II. The dynamic stability situation in CSG
Over 1600kM
Yunnan
Guizhou
Guangxi Guangdong
Hainan
II. The dynamic stability situation in CSG
Yunnan-Guizhou Oscillation Mode
0.55Hz~0.60Hz
Yungui-Guangdong Oscillation Mode
0.40Hz~0.45
Guizhou 500kV grid
Yunnan 500kV grid
Guangdong 500kV grid
Hainan-Main Grid Oscillation Mode
0.70~0.78Hz
Moreover, there are
several inter-area
oscillation modes that
depend on local power
flow hard to analysis
and control.
Outline
I. Introduction
II. The dynamic stability situation in CSG
III. The structure of Integrated Low Frequency Oscillation Defense System
IV. Discussion of Improving the Defense Line
V. Conclusion
III. The structure of Integrated Low Frequency Oscillation Defense System
The 1st defense line
The 2ed defense line
The 3ird defense line
Oscillation monitoring and warning
applications based on WAMS and SCADA
HVDC/UHVDC additional control function
represented by fast DC power modulation and
the coordinated HVDC damping control
system .
The centralized and decentralized dispatching
control system based on
integrated emergency response plan
oscillation warming application based on SCADA
III. The structure of Integrated Low Frequency Oscillation Defense System
The 1st defense line
Oscillation time duration over 20s;
Power swings around base value;
Oscillation amplitude over threshold value;
Power swings similarly on input and output terminal of
the device.
(1)Voice alarm;
(2)The device that occurred power oscillation firstly
Warning output
(1)Voice alarm;
(2)The device that occurred power oscillation firstly;
(3) dormitory frequency, maximum variation amplitude
oscillation warming application based on WAMS
III. The structure of Integrated Low Frequency Oscillation Defense System
The 1st defense line
Oscillation criterion:
Dumpling level calculated by continues twice Prony
analysis less than threshold value ;
Warning output
On-line Prony analysis with
10s interval
HVDC/UHVDC additional control function
III. The structure of Integrated Low Frequency Oscillation Defense System
The 2ed defense line
For single HVDC/UHVDC: Fast DC power
modulation ;
For multi-HVDC/UHVDC: The coordinated HVDC
damping control system.
Oscillation control operations
III. The structure of Integrated Low Frequency Oscillation Defense System
Oscillation control operations by the 2ed defense line
Assumed serious N-2
500kV lines trip
Fast DC power modulation
Yungui-Guangdong Oscillation Mode
Guizhou 500kV grid
Yunnan 500kV grid
Guangdong 500kV grid
Xing-An HVDC
Gao-Zhao HVDC
III. The structure of Integrated Low Frequency Oscillation Defense System
The coordinated HVDC damping control system
Control substation
Master Control Station
2M Channel for order
Luodong
Baoan
Dispatching Center
Gaopo substation
Anshun
Xingren substation
Luoping
Xingan DC
Pole Control
System
Gaozhao DC
Pole Control
System
2M Channel
for data
III. The structure of Integrated Low Frequency Oscillation Defense System
The coordinated HVDC damping control system
Continuous
feedback
control system
Inter-area frequency
difference caused by system
disturbance
500kV AC lines trip
Large capacity generators
trip
Mono-polar or bipolar block
of DC transmission
systems
modulated DC power output
Modulated power output of Xinan pole I(MW)
Time(s)
dead area 0~0.0017Hz
Control
substation
Modulation command
III. The structure of Integrated Low Frequency Oscillation Defense System
The coordinated HVDC damping control system
III. The structure of Integrated Low Frequency Oscillation Defense System
28 30 32 34 36 38 40 42 44 46
-0.01
0
0.01
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(H
z)
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28 30 32 34 36 38 40 42 44 46
4.7
4.8
4.9
5
5.1
5.2
5.3
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?(
V)
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Frequency
difference(Hz)
Time(s)
output(V)
The coordinated HVDC damping control system
At 00:02:30 of Nov,8,
2009, during the
process of blocking
pole2 of Gaopo-
Zhaoqing HVDC,
pole1 tripped.
The centralized and decentralized dispatching control system based on
integrated emergency response plan
III. The structure of Integrated Low Frequency Oscillation Defense System
The 3rd defense line
The 1st and 2ed defense lines mainly designed to dealing with weak/negtive
dumpling oscillations in 500kV grid. However, these defense lines could not
cover two oscillation types.
Oscillations under 500kV grid Forced Oscillations
1) lack of RTU and PMU under 500kV
grid.
2) HVDC power modulation in 500kV
grid could not change power flow and
dumping level under 500kV grid.
1) Locating oscillation source is
supposed to be more complex.
2) Conventional control strategies
show no positive performance.
III. The structure of Integrated Low Frequency Oscillation Defense System
The 3rd defense line
Generation
plants
Converter
Stations Substations
Grid
dispatchers
integrated emergency
response plan
Centralized control
Decentralized Control
Oscillation information communication
• Forced oscillation control strategy in the 3rd defense line
1) stabilize AGC target value or switch to manual control.
2) stabilize generation unit valve
3) Other necessary operation suggested by emergency response plan.
1)Increase voltage level of oscillation area; 2)Regulate DC power to strength electric connection between different provincial grids. 3) Other necessary operation suggested by emergency response plan.
Disconnect generation unit from power gird if oscillation expands
III. The structure of Integrated Low Frequency Oscillation Defense System
Generation plants Grid dispatchers
Decrease generation unit out put to minimum level
• Oscillation control strategy for grid under 500kV in the 3rd defense line
1)Locate the oscillation device by
the first defense line.
2)Give suggestions to dispatchers
of grid under 500kV.
3)Other necessary operation
suggested by emergency
response plan.
1) Search for oscillation source
based on the PRELIMINARY location
result by Dispatchers of 500kV gird.
2) Other necessary operation
suggested by emergency response
plan.
III. The structure of Integrated Low Frequency Oscillation Defense System
Dispatchers of 500kV gird Dispatchers of grid under 500kV
Outline
I. Introduction
II. The dynamic stability situation in CSG
III. The structure of Integrated Low Frequency Oscillation Defense System
IV. Discussion of Improving the Defense Line
V. Conclusion
IV. Discussion of Improving the Defense Line
Improve the 1st defense line by transient energy flow method
t
iijPEi dtPtV0
t
jjiPEj dtPtV0
Transient energy flow
Oscillation source generator
The transient energy give out a clear way to locate forced oscillation source: the source generator always outputs transient energy to grid and can be located by searching backward along the transient energy flow.
IV. Discussion of Improving the Defense Line
Improve the 1st defense line by transient energy flow method
0.026MJ
0.014MJ
0.030MJ
0.112MJ
0.017MJ
Generation plant A
Generation plant B
Generation plant C
10s after forced oscillation started
Oscillation source
Generation plants Converter Stations Substations
Fast Regulation commands
Grid Fault Information
Integrated emergency
response plan database
The First Defense Line
Conform and issue
manually
IV. Discussion of Improving the Defense Line
Improve the 3rd defense line by FCNC(Fast control & network command)
Outline
I. Introduction
II. The dynamic stability situation in CSG
III. The structure of Integrated Low Frequency Oscillation Defense System
IV. Discussion of Improving the Defense Line
V. Conclusion
V. Conclusion
During ten years development, CSG has established an integrated low
frequency oscillation defense system .The defense system shows effective,
precise and sensitive performance in practical operations.
The first defense line could provide valuable warning signal and preliminary
analysis result. The second defense line could cover most inter-area low
frequency oscillation modes. The third defense line shows strong flexibility and
has successfully handled several low frequency oscillation incidents so far.
The defense system is still being developed nowadays. New technologies
and research achievements such as the oscillation source locating method
based on transient energy flow and rapid dispatch command system are
introduced to make it a more powerful and accurate one.