WIP: bugfixes for B2B configuration, NaN results for inactive bus_dc,…

… better handling of vsc status when connected to inactive bus/bus_dc

pandapower/auxiliary.py

@@ -40,12 +40,12 @@
 
 from pandapower.pypower.idx_brch import F_BUS, T_BUS, BR_STATUS
 from pandapower.pypower.idx_brch_dc import DC_BR_STATUS, DC_F_BUS, DC_T_BUS
-from pandapower.pypower.idx_bus import BUS_I, BUS_TYPE, NONE, PD, QD, VM, VA, REF, VMIN, VMAX, PV
+from pandapower.pypower.idx_bus import BUS_I, BUS_TYPE, NONE, PD, QD, VM, VA, REF, PQ, VMIN, VMAX, PV
 from pandapower.pypower.idx_gen import PMIN, PMAX, QMIN, QMAX
 from pandapower.pypower.idx_ssc import SSC_STATUS, SSC_BUS, SSC_INTERNAL_BUS
 from pandapower.pypower.idx_tcsc import TCSC_STATUS, TCSC_F_BUS, TCSC_T_BUS
-from pandapower.pypower.idx_vsc import VSC_STATUS, VSC_BUS, VSC_INTERNAL_BUS, VSC_BUS_DC
-from .pypower.idx_bus_dc import DC_VMAX, DC_VMIN, DC_BUS_I, DC_BUS_TYPE, DC_NONE, DC_REF, DC_B2B
+from pandapower.pypower.idx_vsc import VSC_STATUS, VSC_BUS, VSC_INTERNAL_BUS, VSC_BUS_DC, VSC_MODE_AC, VSC_MODE_AC_SL
+from .pypower.idx_bus_dc import DC_VMAX, DC_VMIN, DC_BUS_I, DC_BUS_TYPE, DC_NONE, DC_REF, DC_B2B, DC_P
 
 try:
     from numba import jit
@@ -866,7 +866,8 @@ def _select_is_elements_numba(net, isolated_nodes=None, isolated_nodes_dc=None,
                     if controllable_in_service.any():
                         is_elements["%s_controllable" % element_table] = controllable_in_service
                         element_in_service = element_in_service & ~controllable_in_service
-            is_elements[element_table] = element_in_service
+            # if element_table has both bus and bus_dc e.g. "vsc":
+            is_elements[element_table] = is_elements.get(element_table, True) & element_in_service
 
     if len(net.vsc) > 0 and "aux" in net["_pd2ppc_lookups"]:
         # reasoning: it can be that there are isolated DC buses. But they are only discovered
@@ -875,7 +876,24 @@ def _select_is_elements_numba(net, isolated_nodes=None, isolated_nodes_dc=None,
         # This does not happen because for that we would need to perform another connectivity check
         # So we do it by hand here:
         vsc_aux_isolated = net["_pd2ppc_lookups"]["aux"]["vsc"][~is_elements["vsc"]]
+        # vsc_aux_isolated = net["_pd2ppc_lookups"]["aux"]["vsc"][~is_elements["vsc"] |
+        #                    ppc_bus_isolated[net["_pd2ppc_lookups"]["aux"]["vsc"]] |
+        #                    ppc_bus_isolated[net._ppc["vsc"][:, VSC_BUS].astype(np.int64)]]
         net._ppc["bus"][vsc_aux_isolated, BUS_TYPE] = NONE
+        # if there are no in service VSC that define the DC slack node, we must change the DC slack to type P
+        bus_dc_slack = net._ppc["bus_dc"][:, DC_BUS_TYPE] == DC_REF
+        bus_dc_with_vsc = net._ppc["vsc"][is_elements["vsc"], VSC_BUS_DC]
+        bus_dc_to_change = bus_dc_slack & (~np.isin(net._ppc["bus_dc"][:, DC_BUS_I], bus_dc_with_vsc))
+        net._ppc["bus_dc"][bus_dc_to_change, DC_BUS_TYPE] = DC_P
+
+        # if the AC bus is defined as REF only because it is connected to a vsc, and the vsc is out of service,
+        # it cannot be a REF bus anymore
+        bus_ac_slack = net._ppc["bus"][:, BUS_TYPE] == REF
+        bus_ac_with_vsc = net._ppc["vsc"][is_elements["vsc"], VSC_BUS]
+        bus_ac_to_change = (bus_ac_slack & (~np.isin(net._ppc["bus"][:, BUS_I], bus_ac_with_vsc)) &
+                            (~np.isin(net._ppc["bus"][:, BUS_I], net._ppc["internal"]["ac_slack_buses"])))
+        # changing just to PQ is OK because the setting of type PV happens later in build_gen
+        net._ppc["bus"][bus_ac_to_change, BUS_TYPE] = PQ
 
     is_elements["bus_is_idx"] = net["bus"].index.values[bus_in_service[net["bus"].index.values]]
     is_elements["bus_dc_is_idx"] = net["bus_dc"].index.values[bus_dc_in_service[net["bus_dc"].index.values]]

pandapower/build_bus.py

@@ -463,20 +463,23 @@ def set_reference_buses(net, ppc, bus_lookup, mode):
         return
     eg_buses = bus_lookup[net.ext_grid.bus.values[net._is_elements["ext_grid"]]]
     ppc["bus"][eg_buses, BUS_TYPE] = REF
+    ppc["internal"]["ac_slack_buses"] = set(eg_buses)  # needed later in _select_is_elements_numba
     if mode == "sc":
         gen_slacks = net._is_elements["gen"]  # generators are slacks for short-circuit calculation
     else:
         gen_slacks = net._is_elements["gen"] & net.gen["slack"].values
     if gen_slacks.any():
         slack_buses = net.gen["bus"].values[gen_slacks]
         ppc["bus"][bus_lookup[slack_buses], BUS_TYPE] = REF
-
+        ppc["internal"]["ac_slack_buses"] |= set(bus_lookup[slack_buses])  # needed later in _select_is_elements_numba
+    ppc["internal"]["ac_slack_buses"] = list(ppc["internal"]["ac_slack_buses"])
 
 def set_reference_buses_dc(net, ppc, bus_lookup, mode):
     if mode == "nx":
         return
     vsc_dc_slack = net.vsc.control_mode_dc.values == "vm_pu"
-    ref_buses = bus_lookup[net.vsc.bus_dc.values[net._is_elements["vsc"] & vsc_dc_slack]]
+    vsc_ac_slack = net.vsc.control_mode_ac.values == "slack"  # VSC that defines AC slack cannot define DC slack
+    ref_buses = bus_lookup[net.vsc.bus_dc.values[net._is_elements["vsc"] & vsc_dc_slack & ~vsc_ac_slack]]
     ppc["bus_dc"][ref_buses, DC_BUS_TYPE] = DC_REF
 
     # identify back-to-back converters:

pandapower/build_gen.py

@@ -366,7 +366,8 @@ def _check_for_reference_bus(ppc):
         raise UserWarning("No reference bus is available. Either add an ext_grid or a gen with slack=True")
 
     # todo test this
-    bus_dc_relevant = np.flatnonzero(ppc["bus_dc"][:, DC_BUS_TYPE] != DC_NONE)
+    bus_dc_type = ppc["bus_dc"][:, DC_BUS_TYPE]
+    bus_dc_relevant = np.flatnonzero(bus_dc_type != DC_NONE)
     ref_dc, b2b_dc, _ = bustypes_dc(ppc["bus_dc"])
     # throw an error since no reference bus is defined
     if len(bus_dc_relevant) > 0 and len(ref_dc) == 0 and len(b2b_dc) == 0:

pandapower/pd2ppc.py

@@ -182,9 +182,6 @@ def _pd2ppc(net, sequence=None):
     # Also deactivates lines if they are connected to two out of service buses
     _branches_with_oos_buses(net, ppc)
 
-    if "pf" in mode:
-        _check_for_reference_bus(ppc)
-
     if check_connectivity:
         if sequence in [None, 1, 2]:
             # sets islands (multiple isolated nodes) out of service
@@ -202,6 +199,10 @@ def _pd2ppc(net, sequence=None):
         # sets buses out of service, which aren't connected to branches / REF buses
         aux._set_isolated_buses_out_of_service(net, ppc)
 
+    # we need to check this after checking connectivity (isolated vsc as DC slack cause change of DC_REF to DC_P)
+    if "pf" in mode:
+        _check_for_reference_bus(ppc)
+
     _build_gen_ppc(net, ppc)
 
     aux._replace_nans_with_default_limits(net, ppc)

pandapower/pypower/newtonpf.py

@@ -169,8 +169,8 @@ def newtonpf(Ybus, Sbus, V0, ref, pv, pq, ppci, options, makeYbus=None):
     # P_dc[vsc[p_set_point_index, VSC_BUS_DC].astype(np.int64)] = -vsc_value_dc[vsc_mode_dc == 1]  # todo sum by group
     vsc_group_buses_p, P_dc_sum, vsc_group_buses_p_number = _sum_by_group(vsc_dc_bus[p_set_point_index], -vsc_value_dc[p_set_point_index], np.ones(sum(p_set_point_index)))
     P_dc[vsc_group_buses_p] = P_dc_sum
-    if len(P_dc_sum) == 0:
-        P_dc_sum = 0.
+    vsc_slack_p_dc_bus, _, _ = _sum_by_group(vsc_dc_bus[vsc_mode_ac == VSC_MODE_AC_SL], vsc_dc_bus[vsc_mode_ac == VSC_MODE_AC_SL], vsc_dc_bus[vsc_mode_ac == VSC_MODE_AC_SL])
+    P_dc_sum_sl = P_dc[vsc_slack_p_dc_bus].copy()  # later used in mismatch for vsc
     #vsc_group_buses_ref, _, vsc_group_buses_ref_number = _sum_by_group(vsc_dc_bus[p_set_point_index], -vsc_value_dc[vsc_mode_dc == 1], np.ones(sum(p_set_point_index)))
 
     # J for HVDC is expanded by the number of DC "P" buses (added below)
@@ -302,7 +302,7 @@ def newtonpf(Ybus, Sbus, V0, ref, pv, pq, ppci, options, makeYbus=None):
                                        ssc_tb[ssc_controllable], Ybus_ssc, ssc_controllable, ssc_set_vm_pu, F,
                                        pq_lookup, vsc_controllable, vsc_fb, vsc_tb, Ybus_vsc, vsc_mode_ac, vsc_mode_dc,
                                        vsc_value_ac, vsc_value_dc, vsc_dc_bus, V_dc, Ybus_hvdc, num_branch_dc, P_dc,
-                                       dc_p, dc_ref, dc_b2b, dc_p_lookup, dc_ref_lookup, dc_b2b_lookup, P_dc_sum)
+                                       dc_p, dc_ref, dc_b2b, dc_p_lookup, dc_ref_lookup, dc_b2b_lookup, P_dc_sum_sl)
         F = r_[F, mis_facts]
 
     T_base = 100  # T in p.u. for better convergence
@@ -473,7 +473,7 @@ def newtonpf(Ybus, Sbus, V0, ref, pv, pq, ppci, options, makeYbus=None):
                                            vsc_fb[vsc_controllable], vsc_tb[vsc_controllable], Ybus_vsc, vsc_mode_ac,
                                            vsc_mode_dc, vsc_value_ac, vsc_value_dc, vsc_dc_bus, V_dc, Ybus_hvdc,
                                            num_branch_dc, P_dc, dc_p, dc_ref, dc_b2b, dc_p_lookup, dc_ref_lookup,
-                                           dc_b2b_lookup, P_dc_sum)
+                                           dc_b2b_lookup, P_dc_sum_sl)
             F = r_[F, mis_facts]
 
         if tdpf:
@@ -592,7 +592,7 @@ def _evaluate_Fx_facts(V,pq ,svc_buses=None, svc_set_vm_pu=None, tcsc_controllab
                        vsc_controllable=None, vsc_fb=None, vsc_tb=None, Ybus_vsc=None,
                        vsc_mode_ac=None, vsc_mode_dc=None, vsc_value_ac=None, vsc_value_dc=None, vsc_dc_bus=None,
                        V_dc=None, Ybus_hvdc=None, num_branch_dc=None, P_dc=None, dc_p=None, dc_ref=None, dc_b2b=None,
-                       dc_p_lookup=None, dc_ref_lookup=None, dc_b2b_lookup=None, P_dc_sum=None):
+                       dc_p_lookup=None, dc_ref_lookup=None, dc_b2b_lookup=None, P_dc_sum_sl=None):
     mis_facts = np.array([], dtype=np.float64)
 
     if svc_buses is not None and len(svc_buses) > 0:
@@ -649,7 +649,7 @@ def _evaluate_Fx_facts(V,pq ,svc_buses=None, svc_set_vm_pu=None, tcsc_controllab
             # this connects the AC slack result and the DC bus P set-point:
             vsc_slack_p = -Sbus_vsc[vsc_tb[ac_mode_sl]].real
             vsc_slack_p_dc_bus, vsc_slack_p_dc, _ = _sum_by_group(vsc_dc_bus[ac_mode_sl], vsc_slack_p, vsc_slack_p)
-            P_dc[vsc_slack_p_dc_bus] = P_dc_sum + vsc_slack_p_dc
+            P_dc[vsc_slack_p_dc_bus] = P_dc_sum_sl + vsc_slack_p_dc
 
         # find the connection between the DC buses and VSC buses
         # find the slack DC buses

pandapower/results.py

@@ -10,7 +10,7 @@
 from pandapower.results_branch import _get_branch_results, _get_branch_results_3ph
 from pandapower.results_bus import _get_bus_results, _get_bus_dc_results, _set_buses_out_of_service, \
     _get_shunt_results, _get_p_q_results, _get_bus_v_results, _get_bus_v_results_3ph, _get_p_q_results_3ph, \
-    _get_bus_results_3ph, _get_bus_dc_v_results, _get_p_dc_results
+    _get_bus_results_3ph, _get_bus_dc_v_results, _get_p_dc_results, _set_dc_buses_out_of_service
 from pandapower.results_gen import _get_gen_results, _get_gen_results_3ph, _get_dc_slack_results
 
 BRANCH_RESULTS_KEYS = ("branch_ikss_f", "branch_ikss_t",
@@ -26,7 +26,8 @@
 
 
 def _extract_results(net, ppc):
-    _set_buses_out_of_service(ppc)
+    _set_buses_out_of_service(ppc)  # for NaN results in net.res_bus for inactive buses
+    _set_dc_buses_out_of_service(ppc)  # for NaN results in net.res_bus_dc for inactive buses
     bus_lookup_aranged = _get_aranged_lookup(net)
     bus_dc_lookup_aranged = _get_aranged_lookup(net, "bus_dc")
     _get_bus_v_results(net, ppc)

pandapower/results_bus.py

@@ -9,8 +9,8 @@
 from numpy import complex128
 from pandapower import VSC_INTERNAL_BUS
 from pandapower.auxiliary import _sum_by_group, sequence_to_phase, _sum_by_group_nvals
-from pandapower.pypower.idx_bus import VM, VA, PD, QD, LAM_P, LAM_Q, BASE_KV, NONE, BS
-from pandapower.pypower.idx_bus_dc import DC_VM
+from pandapower.pypower.idx_bus import VM, VA, PD, QD, LAM_P, LAM_Q, BASE_KV, NONE, BS, BUS_TYPE, BUS_I
+from pandapower.pypower.idx_bus_dc import DC_VM, DC_BUS_TYPE, DC_NONE, DC_PD, DC_BUS_I
 
 from pandapower.pypower.idx_gen import PG, QG
 from pandapower.build_bus import _get_motor_pq, _get_symmetric_pq_of_unsymetric_element
@@ -27,14 +27,19 @@
 
 
 def _set_buses_out_of_service(ppc):
-
-    disco = np.where(ppc["bus"][:, 1] == NONE)[0]
+    disco = np.where(ppc["bus"][:, BUS_TYPE] == NONE)[BUS_I]
     ppc["bus"][disco, VM] = np.nan
     ppc["bus"][disco, VA] = np.nan
     ppc["bus"][disco, PD] = 0
     ppc["bus"][disco, QD] = 0
 
 
+def _set_dc_buses_out_of_service(ppc):
+    disco = np.where(ppc["bus_dc"][:, DC_BUS_TYPE] == DC_NONE)[DC_BUS_I]
+    ppc["bus_dc"][disco, DC_VM] = np.nan
+    ppc["bus_dc"][disco, DC_PD] = 0
+
+
 def _get_bus_v_results(net, ppc, suffix=None):
     bus_idx = _get_bus_idx(net)
 

pandapower/test/loadflow/test_facts.py

@@ -1333,8 +1333,10 @@ def test_vsc_hvdc_mode4():
     pp.create_vsc(net, 2, 1, 0.1, 5, control_mode_ac="vm_pu", control_value_ac=1.02, control_mode_dc="p_mw",
                   control_value_dc=5)
 
-    with pytest.raises(UserWarning, match="reference bus for the dc grid"):
-        pp.runpp(net)
+    # all DC buses are set out of service, so there is no error in this case and bus_dc results are NaN
+    # with pytest.raises(UserWarning, match="reference bus for the dc grid"):
+    #     pp.runpp(net)
+    runpp_with_consistency_checks(net)
 
 
 def test_vsc_hvdc_mode5():
@@ -2105,6 +2107,7 @@ def test_2vsc_1ac_2dc(control_mode_ac, control_mode_dc):
             pp.runpp(net)
 
 
+@pytest.mark.skip(reason="DC line connected to D2B VSC configuration not implemented")
 @pytest.mark.parametrize("control_mode_ac", list(product(['vm_pu', 'q_mvar'], repeat=2)))
 @pytest.mark.parametrize("control_mode_dc", list(product(['vm_pu', 'p_mw'], repeat=2)))
 def test_2vsc_2ac_1dc(control_mode_ac, control_mode_dc):
@@ -2135,6 +2138,7 @@ def test_2vsc_2ac_1dc(control_mode_ac, control_mode_dc):
     runpp_with_consistency_checks(net)
 
 
+@pytest.mark.skip(reason="DC line connected to D2B VSC configuration not implemented")
 @pytest.mark.parametrize("control_mode_ac", list(product(['vm_pu', 'q_mvar'], repeat=2)))
 @pytest.mark.parametrize("control_mode_dc", list(product(['vm_pu', 'p_mw'], repeat=2)))
 def test_2vsc_1ac_1dc(control_mode_ac, control_mode_dc):
@@ -2168,13 +2172,14 @@ def test_2vsc_1ac_1dc(control_mode_ac, control_mode_dc):
             pp.runpp(net)
 
 
-def test_vsc_slack_minimal_wrong():  # todo: VSC as slack cannot have DC bus as vm_pu, therefore must be excluded from DC slacks and then raise error that not enough DC slacks
+def test_vsc_slack_minimal_wrong():
     # np.set_printoptions(linewidth=1000, suppress=True, precision=2)
     # from pandapower.test.loadflow.test_facts import *
     net = pp.create_empty_network()
     # AC part
     pp.create_buses(net, 2, 110, geodata=[(200, 0), (400, 0)])
     pp.create_load(net, 1, 10, 4)
+    pp.create_gen(net, 0, 0)
 
     # DC part
     pp.create_bus_dc(net, 110, 'A', geodata=(210, 0))
@@ -2185,14 +2190,15 @@ def test_vsc_slack_minimal_wrong():  # todo: VSC as slack cannot have DC bus as
     pp.create_vsc(net, 0, 0, 0.1, 5, control_mode_ac="slack", control_value_ac=1, control_mode_dc="vm_pu", control_value_dc=1.02)
     pp.create_vsc(net, 1, 1, 0.1, 5, control_mode_ac="slack", control_value_ac=1, control_mode_dc="p_mw", control_value_dc=1)
 
-    pp.runpp(net)
-
-    runpp_with_consistency_checks(net)
-
-    # pp.plotting.simple_plot(net, plot_loads=True, load_size=5)
+    # VSC as slack cannot have DC bus as vm_pu, therefore must be excluded from DC slacks
+    # Then the DC buses are set out of service, and the corresponding VSC are also set out of service
+    # Then the corresponding AC buses are changed from type REF to type PQ, which is valid because type PV is set later
+    # Then runpp raises "no slacks" error:
+    with pytest.raises(UserWarning, match="No reference bus is available"):
+        pp.runpp(net)
 
 
-def test_vsc_slack_minimal_wrong2():  # todo runpp must raise error here that DC grid has no slacks because the first VSC is deactivated because its AC bus is not connected to AC slack
+def test_vsc_slack_minimal_wrong2():
     # np.set_printoptions(linewidth=1000, suppress=True, precision=2)
     # from pandapower.test.loadflow.test_facts import *
     net = pp.create_empty_network()
@@ -2209,11 +2215,11 @@ def test_vsc_slack_minimal_wrong2():  # todo runpp must raise error here that DC
     pp.create_vsc(net, 0, 0, 0.1, 5, control_mode_ac="vm_pu", control_value_ac=1, control_mode_dc="vm_pu", control_value_dc=1.02)
     pp.create_vsc(net, 1, 1, 0.1, 5, control_mode_ac="slack", control_value_ac=1, control_mode_dc="p_mw", control_value_dc=1)
 
-    pp.runpp(net)
-
-    runpp_with_consistency_checks(net)
-
-    # pp.plotting.simple_plot(net, plot_loads=True, load_size=5)
+    # VSC that defines AC slack cannot define DC slack at the same time
+    # DC slack buses that are only connected to VSC AC slacks are converted to type P buses
+    # Then runpp raises "no DC slacks" error:
+    with pytest.raises(UserWarning, match="No reference bus for the dc grid is available"):
+        pp.runpp(net)
 
 
 @pytest.mark.xfail(reason="AC bus same as ext_grid bus not implemented")