[bug] Using minimal_example code results in incorrect result information PandaPower Version 2.14.6

karatekid2501 commented 1 month ago

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Issue

I am testing PandaPower and for some reason when inputting the minimal example code into my project and test the results of the buses I'm getting these results:

vm_pu	va_degree	p_mw	q_mvar
1.020000	0.000000	-0.107265	-0.052675
1.008843	-150.760126	0.000000	0.000000
0.964431	-149.884141	0.100000	0.050000

Instead of this result

vm_pu	va_degree	p_mw	q_mvar
1.020000	0.000000	-0.107265	-0.052675
1.008843	-0.760126	0.000000	0.000000
0.964431	0.115859	0.100000	0.050000

As you can see for some reason the va_degree in both bus 2 and 3 are not the same. I've doubled check on the code to make sure that the code is correct and it is:

import pandapower as pp
def Example():
    try:
        net = pp.create_empty_network()

        #create buses
        bus1 = pp.create_bus(net, vn_kv=20., name="Bus 1")
        bus2 = pp.create_bus(net, vn_kv=0.4, name="Bus 2")
        bus3 = pp.create_bus(net, vn_kv=0.4, name="Bus 3")

        #create bus elements
        pp.create_ext_grid(net, bus=bus1, vm_pu=1.02, name="Grid Connection")
        pp.create_load(net, bus=bus3, p_mw=0.100, q_mvar=0.05, name="Load")

        #create branch elements
        trafo = pp.create_transformer(net, hv_bus=bus1, lv_bus=bus2, std_type="0.4 MVA 20/0.4 kV", name="Trafo")
        line = pp.create_line(net, from_bus=bus2, to_bus=bus3, length_km=0.1, std_type="NAYY 4x50 SE", name="Line")

        #return currentNetwork.bus.to_string()
        pp.runpp(net)
        return net.res_bus

    except Exception:
        return "Error Thrown"

So I am completely stuck on what the issue could be. Any help is appreciated.

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pawellytaev commented 1 month ago

Hi @karatekid2501, could you share your net.trafo.shift_degree? You see there is an exact 150 degree voltage angle difference between your results and the results from the tutorial. if you set your trafo shift to 0, there should be no difference.

Thanks for bringing that up, it's a bug in the minimal example tutorial :-)

karatekid2501 commented 1 month ago

Hi @karatekid2501, could you share your net.trafo.shift_degree? You see there is an exact 150 degree voltage angle difference between your results and the results from the tutorial. if you set your trafo shift to 0, there should be no difference.

Thanks for bringing that up, it's a bug in the minimal example tutorial :-)

Hi @pawellytaev,

Thanks for getting back to me, at least this confirms that I am not going mad and it is a bug.

When printing net.trafo.shift_degree, it is reporting back 150. I'm assuming I would need to use the create_transformer_from_parameters function but I am unsure what to put in the extra parameters required to ensure that the results match the minimal tutorial outcome.

pawellytaev commented 1 month ago

Hi @karatekid2501, this should work:

traf0 = pp.create_transformer_from_parameters(net, hv_bus=bus1, lv_bus=bus2, name="Trafo", sn_mva=0.4, vn_hv_kv=20.0, 
                                              vn_lv_kv=0.4, vk_percent=6.0, vkr_percent=1.425, pfe_kw=1.35, i0_percent=0.3375,
                                              shift_degree=0, tap_min=-2, tap_max=2, tap_pos=0)

I basically copied all the trafo parameters from the net.trafo table but made shift_degree=0. You can find more information on how to create customized elements here: https://github.com/e2nIEE/pandapower/blob/develop/tutorials/create_advanced.ipynb

e2nIEE / pandapower