PSCAD电力系统次同步振荡分析介绍

Z(f)
0.0 100 [Hz]
#2 #1
IH VH
6.08320.4323
21.977
0.05178 VI
VMac 1
Mag (31) FFT
Ph (31)
F = 5 [Hz] dc
Ifa
System Group
4830.0 0.0345
Mag
VI
(31) FFT
1
Ph
(31)
F = 5 [Hz] dc
–Voltage amplification.
Induction Generator Effect
– Simulation Example
cfld VC
vfld Mactiv
S/H out in
hold
Ef0 w
376.99
telec Te
Ef If S
Tm Tm s tdy
w Tm
1.0
3 Phase RMS
Observe the following
• Effect when the system resistance is lowered • Effect of resistance on damping • Rotor electrical time constants • Harmonics
Induction Generator Effect
– Simulation results
R=6 Ohms
R=2 Ohms
Machine Output Volts p.u.
Machine Output Volts p.u.
1.000 0.950 0.900 0.850 0.800 0.750
1.100 1.050 1.000 0.950 0.900 0.850 0.800 0.750 0.700
Introduction to Sub Synchronous Effects in Power Networks
Dharshana Muthumuni Manitoba HVDC Research Centre
Outline
-Electrical resonance in the network
- Super synchronous resonance's - Sub synchronous resonance's - Series compensation
- Mechanical system of a turbine- generator
- Mechanical system resonance's
linev
VMac
Initial Angle of source = -14.9 deg. Initial Ramp up time = 0.2 sec. Machine enabled at = 1.1 sec.
m cs w
Tim er
Y winding leads the delta winding by 30 degrees.
R=0
BRK
Ia2 1.0
0.1 Ea2
50.0
Tim ed Breaker Logic Open@t0
来自百度文库
BRK
L 0.1 C 110 6
1 f
2 LC
f 503.292
Network Electrical Characteristics
• Frequency response of the network
y
Sub Synchronous Resonance
• Addition of power system components cause the resonance points to shift.
• A resonance point at a frequency below the system frequency is termed Sub Synchronous.
VBUS11 BUS
BUS Bus 11 Bus 13
VBUS13
TL6-11
TL10-11 BUS
Bus 10
TL13-10 VBUS10
TRNS 3
BUS Bus 32
VBUS32
GEN 3
BUS load
Bus 20 VBUS20
TRNS 5
BUS Bus 33 VBUS33
GEN 4
BUS Bus 34
– Resonance points. – Damping is due to loads and losses. – Multiple resonance points in a complex power
network. – Location of the disturbance.
Network Electrical Characteristics
TL2-25
BUS
Bus 2
VBUS2
TL2-3
VBUS18
BUS
Bus 18
load
TL17-18 TL3-18
BBuUsS28 VBUS28
load
VBUS27
load
BUS
TL26-27 TL17-27
TL16-17
Bus 27
BUS load
Bus 29
TRNS 9
VBUS29
BBuUsS38 VBUS38
Induction Generator Effect
– Simulation Example
cfld VC
vfld Mactiv
S/H out in
hold
Ef0 w
376.99
telec Te
Ef If S
Tm Tm s tdy
w Tm
1.0
3 Phase RMS
linev
VMac
Initial Angle of source = -14.9 deg. Initial Ramp up time = 0.2 sec. Machine enabled at = 1.1 sec.
m cs w
Tim er
Y winding leads the delta winding by 30 degrees.
Z(f)
0.0 100 [Hz]
#2 #1
IH VH
6.08320.4323
21.977
0.05178 VI
VMac 1
Mag (31) FFT
Ph (31)
F = 5 [Hz] dc
500 Hz
1000 Hz
System Response to a Disturbance
y
y
Ea1 40
Main : Graphs
-40
Ia1 0.150 0.100 0.050 0.000 -0.050 -0.100 -0.150
Ia2 0.040
-0.040
0.160 0.180 0.200 0.220 0.240 0.260 0.280 ... ... ...
Is
1R.0s
0L.s1
R1.r0
L0.r1
1.0
0.1
(1-s)/sRr
Ws Wr S
Ws
Rr
Effective rotor resistance
s
• Negative for generator action
– If the negative resistance is greater than the total network resistance seen from the rotor, self-excitation will occur.
• Addition of series compensation can cause sub synchronous resonance points.
Sub Synchronous Resonance
• Problems associated with Sub Synchronous Currents and voltages (SSR Problems)
VBUS34
GEN 5
TL24--23
GEN 6
BBuUsS35
VBUS35
6 TRNS
VBUS22 BUS Bus 22
TL21-22
TL22-23
BUS load
Bus 23 VBUS23
TRNS 7
BUS VBUS36
Bus 36
7 GEN
System Response to a Disturbance
-Modeling
-Machines and network -Mechanical system
-SSR Issues
- Induction generator effect - Torsional interactions
Network Electrical Characteristics
• Frequency response of the network
TL15-14
VBUS21
load
Bus 19 VBUS19
BUS
VBUS4 TL4-5
Bus 4 load
BUS
Bus 12
VBUS12
BUS load
Bus 14 VBUS14
TRNS 13
TRNS 4
BUS
Bus 5
BUS
Bus 1
VBUS1
VBUS5
TL5-6
BUS VBUS6
Bus 6
TL1-39
• Oscillations at natural frequency
– Multiple resonance
BRK
Ia1 1.0
0.1 Ea1
Ia2 1.0
5.0 0.04 R=0
System Response to a Disturbance
BRK
Ia1 1.0
0.1 Ea1
Ia2 1.0
5.0 0.04 R=0
TL5-8
TL6-7
BUS
Bus 7
BUSBus 39
VBUS39 load
TL7-8
load TRNS 2
1 GEN
TL9-39
BUS
Bus 8
VBUS8
load
TL8-9
SlaBcUkSBus load
Bus 31 VBUS31
BUS
Bus 9
VBUS9
GEN 2
TRNS TRNS
11
12
TL14-13
Tim ed Fault Logic
ISW ABC->G
Initial Angle of source = -3.813 deg. Initial Ramp up time = 0.2 sec. Source Magnitude = 477.8 kV.
• This system has a electrical resonance point at around 40 Hz
• Frequency response of the network
GEN 8
TL26-29
GEN 10
Bus B3U7S
VBUS37
TL26-28
TL28-29
BUS VBUS30
Bus 30
TRNS 8
BUSBus 26 VBUS26
load
TRNS
10
BUS
Bus 25
VBUS25
load
TL25-26 BUS
Capacitor Volts, A 1.50
Capacitor Volts, A 2.50
1.00
2.00
1.50
0.50
1.00
0.00
0.50
0.00
-0.50
-0.50
20.0
-1.00
-1.00
-1.50
-1.50 -2.00
Machine Current, A,out+ 3.0
– Interference with Power system controls (PSS, Governors etc.)
Induction Generator Effect
– Basic Theory
• Induction generator
– Slip, Effective Negative Resistance
– Self excitation of Machines (感应发电机效应)
– Interaction of the electrical network with the mechanical (shaft) system of a turbine – generator.
• Torsional Interaction （扭振相互作用 small disturbance） • Torque Amplification （扭矩放大 large disturbance）
Ifa
System Group
4830.0 0.0345
Mag
VI
(31) FFT
1
Ph
(31)
F = 5 [Hz] dc
Tim ed Fault Logic
ISW ABC->G
Initial Angle of source = -3.813 deg. Initial Ramp up time = 0.2 sec. Source Magnitude = 477.8 kV.
BUS
Bus 24
load VBUS24
GEN
TL24-16
9
BUS
Bus 16
VBUS16
load
TL16-15
TL16-19
TL16-21 BUS
Bus 21
Bus 17 VBUS17
TL2-1
BUS load
Bus 3
TL3-4
VBUS3
TL4-14
BUS Bus 15 VBUS15
BUS load