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<< Click to Display Table of Contents >> Navigation: Components and parameters > Elements > Synchronous motor |
PARAMETERS
General
Parameter |
Default |
Unit |
Description |
Name |
|
|
Name of the motor |
Pref |
0 |
MVA |
Set real power |
Profile |
Default |
|
Name of the motor power profile |
Mode |
Cos phi control |
|
Cos phi control or reactive power control |
cos(φ) |
0.85 |
|
Set power factor |
Qref |
0 |
Mvar |
Set reactive power |
Q |
absorb |
|
Reactive power direction (absorb / supply) |
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Motor
Parameter |
Default |
Unit |
Description |
Type |
|
|
Type of the motor |
Unom |
1) |
kV |
Nominal voltage of the motor |
Snom |
0 |
MVA |
Nominal apparent power |
cos phi nom |
0.85 |
|
Nominal cos phi |
xd" |
0.2 |
pu |
Sub-transient reactance 2) |
rg |
0 |
pu |
Fictitious resistance |
R/X |
|
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|
Ia/Inom |
|
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1) Unom of the node. In case a step up transformator is applied Unom must be equal to Unom of the node.
2) For the calculation of the short-circuit current the saturated value of xd" is taken
Type
The type list contains all generators from the component type database with a Unom of 80 - 120% of the node nominal voltage. See also: Type
Connection
Parameter |
Default |
Unit |
Description |
Star point earthing |
none |
|
Indicates whether the star point is earthed |
Re |
0 |
Ohm |
Earthing resistance with earthed star point |
Xe |
0 |
Ohm |
Earthing reactance with earthed star point |
External node |
|
|
Name of the external node with a common ground |
No SC contribution |
no |
yes/no |
Indicator that the machine does not contribute to a short-circuit (in case of inverter connected synchronous motor) |
External node
Possibility to connect the neutral point of the generator to the earthing electrode at another node .
No SC contribution
Can be used to make the motor act like a load during a fault analysis or IEC 60909 calculation.
Dynamics
Parameter |
Default |
Unit |
Description |
Rotor |
turbo |
|
Rotor type |
Rg |
0 |
pu |
Stator resistance |
Xl |
0 |
pu |
Leakage reactance |
Xd |
0 |
pu |
Synchronous reactance, d-as |
Xq |
0 |
pu |
Synchronous reactance, q-as |
X0 |
0 |
pu |
Zero sequence reactance |
Xd' |
0 |
pu |
Transient reactance, d-as |
Xq' |
0 |
pu |
Transient reactance, q-as |
Xd" |
0,2 |
pu |
Sub-transient reactance, d-as |
Xq" |
0 |
pu |
Sub-transient reactance, q-as |
Type |
short-circuit |
|
Time constant type |
Td' |
0 |
s |
Transient time constant, d-as |
Tq' |
0 |
s |
Transient time constant, q-as |
Td" |
0 |
s |
Sub-transient time constant, d-as |
Tq" |
0 |
s |
Sub-transient time constant, q-as |
H |
0 |
s |
Inertia |
KD |
0 |
pu |
Mechanical damping constant |
Reliability
Parameter |
Default |
Unit |
Description |
Failure frequency |
0 |
per year |
Mean number of occurrences that the motor fails (short circuit) |
Repair duration |
0 |
minutes |
Mean duration of repair or replacement |
Maintenance frequency |
0 |
per year |
Mean number of occurrences thet the motor is in maintenance |
Maintenance duration |
0 |
minutes |
Mean duration of maintenance |
maint. cut-off duration |
0 |
minutes |
Mean duration of cancellation of maintenance in case of emergency |
MODELLING
Loadflow
In load flow calculations, a synchronous generator with cos phi control is represented as a negative load.
Pload = Pref
and
Qload = Pref * √ ( 1 - cos(φ)² ) / cos(φ) (absorb)
or
Qload = - Pref * √ ( 1 - cos(φ)² ) / cos(φ) (supply)
Motor start
The starting current to rated current ratio is equal to 1/(Rg+Xd").
IEC 60909 and Fault analysis
Modelling of the synchronous generator with cos-phi control is identical to modelling of a synchronous generator with voltage control.
IEC 60909 minimum short circuit calculation without synchronous motors
In the calculation of Ik"min according to IEC 60909 the partial short circuit current from synchronous motors is neglected. This is in accordance with neglecting the partial short circuit current of asynchronous motors.