diff --git a/pandapower/auxiliary.py b/pandapower/auxiliary.py
index 06d9c8ad2..7e1ee71ba 100644
--- a/pandapower/auxiliary.py
+++ b/pandapower/auxiliary.py
@@ -721,7 +721,7 @@ def _check_connectivity(ppc):
         bus_dc_not_reachable[reachable_dc] = False
         isolated_nodes_dc, pus_dc, qus_dc, ppc = _set_isolated_nodes_out_of_service(ppc, bus_dc_not_reachable, dc=True)
     else:
-        isolated_nodes_dc, pus_dc, qus_dc = np.array([]), 0, 0
+        isolated_nodes_dc, pus_dc, qus_dc = np.array([], dtype=np.int64), 0, 0
 
     return isolated_nodes, pus, qus, isolated_nodes_dc, pus_dc, qus_dc
 
diff --git a/pandapower/converter/powerfactory/validate.py b/pandapower/converter/powerfactory/validate.py
index 1c7a59f18..20407777a 100644
--- a/pandapower/converter/powerfactory/validate.py
+++ b/pandapower/converter/powerfactory/validate.py
@@ -405,7 +405,7 @@ def _validate_pf_conversion_balanced(net, in_both, all_diffs):
         bus_dc_diff = net.res_bus_dc.loc[bus_dc_idx].pf_vm_pu - net.res_bus_dc.loc[
             bus_dc_idx].vm_pu
         bus_dc_id = abs(bus_dc_diff).abs().idxmax().astype('int64')
-        logger.info("Maximum bus_dc vm_pu difference between pandapower and powerfactory: %.1f "
+        logger.info("Maximum bus_dc vm_pu difference between pandapower and powerfactory: %.6f "
                     "p.u. at bus_dc %d (%s)" % (
                         max(abs(bus_dc_diff)), bus_dc_id, net.bus_dc.at[bus_dc_id, 'name']))
         all_diffs["bus_dc_diff"] = bus_dc_diff
diff --git a/pandapower/pd2ppc.py b/pandapower/pd2ppc.py
index e75ca73be..9cfc32129 100644
--- a/pandapower/pd2ppc.py
+++ b/pandapower/pd2ppc.py
@@ -179,6 +179,7 @@ def _pd2ppc(net, sequence=None):
             # sets islands (multiple isolated nodes) out of service
             if "opf" in mode:
                 net["_isolated_buses"], _, _ = aux._check_connectivity_opf(ppc)
+                net["_isolated_buses_dc"] = np.array([], dtype=np.int64)
             else:
                 net["_isolated_buses"], _, _, net["_isolated_buses_dc"], _, _ = aux._check_connectivity(ppc)
             net["_is_elements_final"] = aux._select_is_elements_numba(net, net._isolated_buses,
diff --git a/pandapower/plotting/powerflow_results.py b/pandapower/plotting/powerflow_results.py
index d8cac3e30..ff2853b95 100644
--- a/pandapower/plotting/powerflow_results.py
+++ b/pandapower/plotting/powerflow_results.py
@@ -71,7 +71,7 @@ def plot_voltage_profile(net, ax=None, plot_transformers=True, xlabel="Distance
     if ax is None:
         plt.figure(facecolor="white", dpi=120)
         ax = plt.gca()
-    if not net.converged:
+    if not net.converged and not net.OPF_converged:
         raise ValueError("no results in this pandapower network")
     if lines is None:
         lines = net.line.index