# power flow convergence，but Pgen is greater than Pmax

We are calculating the power flow convergence of some cases, but we encounter a strange phenomenon. The power flow calculation result is the system power flow convergence, but the Pgen of swing generator is greater than Pmax. The detailed results are as follows

SWING BUS SUMMARY:

BUS#-SCT X-- NAME --X BASKV PGEN PMAX PMIN QGEN QMAX QMIN

31 BUS-31 100.00 797.9* 600.0 0.0 262.1 99900.0-99900.0

1. We can see that pgen is 797.7 and Pmax is 600, but the result is power flow convergence. We are very confused about this. Does anyone know how to solve this problem? At the same time, we want to know whether pgen and Pmax can be obtained through python. Then, we help judge the convergence by comparing their values.
2. Is there a way to judge whether the system generator output, branch power flow and node voltage meet the limits through Python. Thank you very much.
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You need to increase the dispatch of other generators connected to Type 2 Buses. The swing generator represents a physical machine so you have to honor its Pmax/Pmin limits when solving the power flow.

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To retrieve values for Pgen and Pmax, use the python API "MACDAT". Check the API manual for details.

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There is nothing strange here. There are no P limits at a swing bus. The swing bus will supply the power necessary to maintain the active power balance in the system, i.e. the total generation = total consumtion + losses.

You have to increase PGEN for some type 2 generator nodes with at least 200 MW and solve again. Or decrease the load with 200 MW.

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