PSCAD Example
Salient and Non-salient Models for
Synchronous Generator
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a division of Manitoba Hydro International Ltd.
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Winnipeg, MB R3P 1A3, Canada
www.hvdc.ca
PSCAD Example
Salient and Non-salient Models for Synchronous Generator
Salient pole or non-salient pole synchronous generators can be identified in PSCAD by
defining the number of q-axis damper windings. For a salient pole synchronous machine
“No. of Q-axis Damper Windings” should be selected as “One”:
Figure 1: a salient pole synchronous generator settings
For a non-salient pole synchronous machine “No. of Q-axis Damper Windings” should
be selected as “two”:
©2013 Manitoba HVDC Research Centre a division of Manitoba Hydro International Ltd.
Init, Sep 1, 2016
PSCAD Example
Figure 2: a non-salient pole synchronous generator settings
©2013 Manitoba HVDC Research Centre a division of Manitoba Hydro International Ltd.
Init, Sep 1, 2016
PSCAD Example
The reactance and transient time constants should be selected accordingly:
(a)
(b)
Figure 3: (a) Salient pole (b) non-salient pole synchronous machine typical parameters
Case 1: Salient pole synchronous Generator Example
This example discusses a salient pole synchronous generator. The Generator connected
to; (i) Exciter, (ii) Power system stabilizer, (iii) Multimass, (iv) Hydro Governor and (v)
Hydro Turbine. Brief descriptions of all the components are given next.
©2013 Manitoba HVDC Research Centre a division of Manitoba Hydro International Ltd.
Init, Sep 1, 2016
PSCAD Example
S/H
in out
hold
Pow er Syst em
Stabilizer
S2M
Vref0 Vref
VS
Exciter_(AC1A)
VT
Ef0
IT 3
Ef
If
Vs
PSS1A
EXCIT ER
Mult imass
Multimass
( SyncM/c)
Tm
Te Wrad
IF
EF
Ef0
w
3
T ransmission line divided in
t w o sect ions to apply a fault
in the middle. T line_1 is
50km and T line_2 is 20km
Salient Pole generat or
A
V
Ef If
S
Te
#2
A
V
25
230 / 13.8
umec
#1
A
V
Simple Syst em Equivalent
Source Representat ion
RRL
T Line_1
vpcc
T Line_2
Tm
w Tm
z
Hydro Gov 1
z0
Wref
Tmstdy
z
w
Tm
8.42 [mH]
W
w
3.174 [ohm]
TM
Tm0
AB->G
Fault
Timed
Fault
Logic
Remot
e fault
Remot
e fault
Hydro Tur 1
zi
W ref
Local Load
1.0
Hydro T urbine
Hydro Gov
Figure 4: Synchronous machine and the connected power system
1- Exciter
A standard IEEE type exciter (i.e AC1A) is selected in this example. Other type of exciters
can be selected in the model:
©2013 Manitoba HVDC Research Centre a division of Manitoba Hydro International Ltd.
Init, Sep 1, 2016
PSCAD Example
Select other type of IEEE standards for exciter
All input parameters are either entered in seconds (time constants) or per-unit (all other
inputs). The various external inputs and outputs described below:
Inputs:
Ef0: This input defines the output field voltage to the machine during the
initialization period. Ef0 can be either defined by the user or can be
defined from within the attached synchronous machine (through a Wire).
[VT/IT]: This input is a 3-element array and receives its data from the
attached synchronous machine (provided that the machine is set to output
this data). VT is the RMS terminal voltage. IT is the synchronous machine
terminal current and is complex (i.e. has a real and imaginary component).
The real component of IT is in phase with VT and the imaginary
component of IT is in quadrature (lagging is positive) with VT.
VS: This input is provided only when using the exciter with a power
system stabilizer.
©2013 Manitoba HVDC Research Centre a division of Manitoba Hydro International Ltd.
Init, Sep 1, 2016
PSCAD Example
Vref: This input defines the voltage reference for the synchronous
machine terminals. The value can be derived from a number of different
components, which might include a slider, a real constant component or
some other signal.
Outputs:
Ef: This output is the computed field voltage applied directly to
synchronous machine. A Wire may be used to make the connection.
Vref0: This output is the initialized value of the reference voltage Vref and
can be applied at the users discretion.
More information regarding “Exciter Models” and “Transfer Functions” are available in
PSCAD Online help system.
2- Power system Stabilizer
A standard IEEE type power system stabilizers (i.e. PSS1A) is selected in this example.
Other type of stabilizers can be selected in the model:
©2013 Manitoba HVDC Research Centre a division of Manitoba Hydro International Ltd.
Init, Sep 1, 2016
PSCAD Example
Figure 5: Select other type of IEEE standards for power stabilizer
The inputs to this model are per-unit speed w, synchronous machine terminal voltage Vt
and discontinuous controller reference Vk. The output is Vs, which can be speed,
terminal frequency, power or none. More information about the Power System Stabilizer
Models and their Transfer Functions are available Online in PSCAD help system.
3- Multimass
This component simulates the dynamics of up to 26 masses connected to a single
rotating shaft. In this example 4 masses are selected as the number of turbines.
One mass is normally used to represent the generator, and the electrical torque Te is
applied to it. One mass may be used to represent an exciter. The remaining masses
represent turbines, and the mechanical torque Tm is divided among them. The resulting
speed of the generator Wpu or Wrad is then output, for use as input to the interfaced
machine model.
©2013 Manitoba HVDC Research Centre a division of Manitoba Hydro International Ltd.
Init, Sep 1, 2016
PSCAD Example
4- Hydro Turbines
A standard IEEE type hydro turbine (i.e. Tur1) is selected in this example. Other type of
Hydro Turbines can be selected using the parameters “Elastic Water Column” and “Surge
Tank” in the model:
©2013 Manitoba HVDC Research Centre a division of Manitoba Hydro International Ltd.
Init, Sep 1, 2016
PSCAD Example
The inputs to this model are per-unit speed w, per-unit speed reference Wref and gate
position z. The outputs are the mechanical torque Tm (which is input to the
Synchronous Machine) and initial gate position zi (which is input to the associated
Hydro Governor for initialization. For more information regarding the turbine models
and transfer functions please refer to online PSCAD help system.
5- Hydro Governor
This component can represent one of three IEEE type hydro governor models i.e:
GOV1: Mechanical-Hydraulic Controls
GOV2: PID Controls including Pilot and Servo Dynamics
GOV3: Enhanced Controls for Load Rejection Studies
The inputs to this component are per-unit speed w, per-unit speed reference Wref and
gate position during initialization z0. The output is the gate position z. More
©2013 Manitoba HVDC Research Centre a division of Manitoba Hydro International Ltd.
Init, Sep 1, 2016
PSCAD Example
information about the Hydro Governor Models and their Transfer Functions are available
Online in PSCAD help system.
The dynamics of the system for a three-phase to ground fault is shown in the following
figure:
Synchronous Machine,Field V oltage,Main
Power (MW)
140
120
100
80
60
40
20
0
-20
-40
Reactive Power (MVAR)
300
250
200
150
100
50
0
-50
-100
-150
speed (rad/s)
377.80
377.60
REAL POW ER
REACT IV E POW ER
OMEGA
377.40
377.20
377.00
376.80
376.60
376.40
FIELD VOLTAGE
Field Voltage (pu)
2.40
2.20
2.00
1.80
1.60
1.40
14.00
V rms
13.50
Voltage (kV)
13.00
12.50
12.00
11.50
11.00
x
5.0
10.0
15.0
20.0
25.0
30.0
35.0
Figure 6: Dynamics of salient synchronous generator and the connected power system
PSCAD
Refer to PSCAD case: SalientGenerator.pscx
©2013 Manitoba HVDC Research Centre a division of Manitoba Hydro International Ltd.
Init, Sep 1, 2016
PSCAD Example
Case 2: Non-salient pole synchronous Generator Example
The dynamics of the non-salient synchronous machine are given in the following figure.
As can be seen the dynamics of the synchronous machine takes longer time to damp
compare to the silent pole.
speed (rad/s)
Reactive Power (MVAR)
Power (MW)
Synchronous Machine,Field V oltage,Main
140
120
100
80
60
40
20
0
-20
-40
300
250
200
150
100
50
0
-50
-100
-150
377.80
377.60
377.40
377.20
377.00
376.80
376.60
376.40
REAL POW ER
REACT IVE POW ER
OMEGA
FIELD V OLT AGE
Field Voltage (pu)
2.40
2.20
2.00
1.80
1.60
1.40
14.00
V rms
Voltage (kV)
13.50
13.00
12.50
12.00
11.50
11.00
5.0
10.0
15.0
20.0
25.0
30.0
35.0
Figure 7: Dynamics of non-salient synchronous generator and the connected power system
PSCAD
Refer to PSCAD case: NonsalientGenerator.pscx
©2013 Manitoba HVDC Research Centre a division of Manitoba Hydro International Ltd.
Init, Sep 1, 2016