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A load can be defined in four different ways with P,Q,I,S, cos phi. The button Appearance is used for switching between them and for converting parameters.
PARAMETERS
General
Parameter |
Default |
Unit |
Description |
Name |
|
|
Name of load |
P |
-> |
|
Absorb/supply real power |
Q |
-> |
|
Absorb/supply reactive power |
P |
0 |
MW |
Real power |
Q |
0 |
Mvar |
Reactive power |
S |
0 |
MVA |
Apparent power |
I |
0 |
A |
Current |
cos phi |
0 |
|
Power factor |
Behaviour |
Default |
|
Name of voltage dependent load behaviour |
Growth |
None |
|
Growth rate of the load |
Profile |
Default |
|
Name of the load profile |
Behaviour
A pre-defined load behaviour can be selected under behaviour to model the voltage dependency of the load.
Growth
Seven fixed growth scenarios are built into Vision: No growth, 1%, 1.5%, 2%, 3%, 4% and 5%, exponentially per year. In addition, a user-defined growth scenario can be chosen.
Profile
A pre-defined load profile can be selected. The default load profile solely consist of values of 1, yielding a constant load over the profile time.
Simultaneity of loads
The stated load is multiplied by the simultaneity of loads (coincidence) factor g. This factor can be specified at the node to which the load is connected and applies for all loads and load part of all transformer loads present at the node.
See also: Simultaneousness.
Controls
Parameter |
Default |
Unit |
Description |
P(U) control |
|
|
P(U)-control present |
P(I) control |
|
|
P(I)-control present |
P(f) control |
|
|
P(f) control present |
U |
|
pu |
Input of the P(U) function |
I |
|
pu |
Input of the P(I) function, directional |
f |
|
Hz |
Input of the P(f) function |
P |
|
pu |
Output of the P(U) or P(I) or P(f) function |
Measurement unit |
|
|
Measurement field where the current is measured (maximum 3; the most restrictive one prevails) |
Reliability
Parameter |
Default |
Unit |
Description |
Failure frequency |
0 |
per year |
Mean number of occurrences that the load fails (short circuit) |
Repair duration |
0 |
minutes |
Mean duration of repair or replacement |
Maintenance frequency |
0 |
per year |
Mean number of occurrences thet the load 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 |
Customers
Parameter |
Default |
Unit |
Description |
Number of large customers |
0 |
|
Number of large customers |
Number of generous cust. |
0 |
|
Number of generous customers |
Number of small cust. |
0 |
|
Number of small customers |
System element |
|
|
The type of generation or consumption |
Power |
0 |
MWp |
The connected power of this system element |
Harmonics
Parameter |
Default |
Unit |
Description |
Type |
|
|
Harmonic source type |
h |
3 to 99 |
|
Harmonic number |
Current |
0 |
% |
Harmonic current, relative to rated load |
Angle |
0 |
degrees |
Harmonic current angle, relative to load flow voltage |
Current and angle:
The harmonic current injection is related to the nominal load current, in percentages:
Current (h) = I (h) / I (1) x 100%
The angle of the harmonic current injection is related to the angle of the voltage in the nominal load flow situation:
Angle (h) = Angle (h) - Angle (1), in degrees
MODELLING
Load flow
Modelling of the load is described under: Load behaviour
IEC 60909
Loads are not taken into consideration in IEC 60909 calculations.
Fault analysis
In sequential fault analysis, the load is modelled as an impedance. This impedance is determined using the pre-fault node voltage and load current, determined in advance by means of a load flow calculation.