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In the Netbeheer Nederland document “Power generating module Document (“PGMD”)” for type B and C electricity generation units, a calculation is required to demonstrate that a wind or solar farm or generator farm meets the grid code requirements for reactive power.
The calculation Power generating module calculates the active and reactive power at the transfer point and shows the results in a table and graph. These results can be appended to the document.
Preparation
A network consisting of solar panels and/or wind turbines and/or synchrounous generators with associated infrastructure (cables, transformer) must be entered.
At the transfer point, the 'grid' must be modeled as a source.
Calculation
Start the calculation with Calculate | Special | Power generating module.
Choose whether or not the inverters provide additional reactive power.
The computation performs 14 loadflows with different settings:
Loadflow |
Source.Uref (pu) |
Power generating unit.p (pu) |
Power generating unit.q (pu) |
0 |
1 |
1 |
0 |
1 |
1 |
0.95 |
-0.33 |
2 |
1 |
0.95 |
0.33 or 0.5 |
3 |
1 |
0.2 |
-0.33 |
4 |
1 |
0.2 |
0.33 or 0.5 |
5 |
1 |
0 |
0 |
6 |
1.1 |
1 |
-0.33 |
7 |
1.1 |
1 |
0 |
8 |
1.05 |
1 |
0.33 or 0.5 |
9 |
0.95 |
0.95 |
0.33 or 0.5 |
10 |
0.95 |
0.95 |
-0.33 |
11 |
0.9 |
0.9 |
0.33 or 0.5 |
12 |
0.9 |
0.9 |
0 |
13 |
0.85 |
0.85 |
0 |
Any controls (except P(I) control) of PVs, wind turbines and batteries are switched off. The requested power is supplied anyway and reactive power possibly supplied or absorbed.
The setting of each PV is:
P := p (pu) * Inverter.Snom, but not greater than the power of the panels
Q := q (pu) * Inverter.Snom
During the load flow at low voltage or with additional reactive power, P and Q are still reduced so that the current does not exceed Inom, calculated as inverter.Snom/node.Unom. At additional reactive power maximal 1.1*Inom.
The setting of each wind turbine is:
P := p (pu) * Type.Pnom
Q := q (pu) * Type.Pnom
The setting of each synchronous generator with cos(phi) control or reactive power control is:
P := p (pu) * Type.Snom
Q := q (pu) * Type.Snom, but between Type.Qmin and Type.Qmax
The setting of each battery is:
P := p (pu) * Inverter.Snom, but not greater than capacity*C-rate
Q := q (pu) * Inverter.Snom
P and Q are here according to the generator convention, but the results are according to the load convention.
During the load flow at low voltage or with additional reactive power, P and Q are still reduced so that the current does not exceed Inom, calculated as inverter.Snom/node.Unom. At additional reactive power maximal 1.1*Inom.
Results
Standard load flow results are available from each load flow:
•Nodes: U
•Branches: P, Q, S, I, load rate, Ploss
•Elements: P, Q, S, I, cos phi, load rate (S/Snom), I/Inom, U
These results are aggregated to:
•Nodes: the minimum and maximum voltage
•Branches: the minimum and maximum load rating
•Elements: the minimum and maximum active power and reactive power
The options for viewing the results are:
•in the diagram
•in Calculate | Results | Overview
•in Calculate | Results | Details
Scheme
At nodes, the minimum and maximum voltage.
At branches, the minimum and maximum load rating.
At elements the minimum and maximum active power and reactive power.
The objects are colored when voltage is exceeded or overloaded.
Calculate | Results | Overview
This screen does not provide much information yet.
Calculate | Results | Details
The results of selected objects are shown.
The button Details shows the results of all load flows in a table.
With the button Graph at elements two graphs are shown successively.