diff --git a/examples/ac-dc-meshed/ac-dc-lopf.py b/examples/ac-dc-meshed/ac-dc-lopf.py
index 10cc49521..4d27ac7d3 100644
--- a/examples/ac-dc-meshed/ac-dc-lopf.py
+++ b/examples/ac-dc-meshed/ac-dc-lopf.py
@@ -44,7 +44,7 @@
     p0 = 0.
     p1 = 0.
 
-    for c in network.iterate_components(pypsa.components.branch_components):
+    for c in network.iterate_components(network.branch_components):
 
         bs = (c.df.bus0 == bus)
 
diff --git a/examples/ac-dc-meshed/ac-dc-lpf.py b/examples/ac-dc-meshed/ac-dc-lpf.py
index f20fdc71c..56a1f9df9 100644
--- a/examples/ac-dc-meshed/ac-dc-lpf.py
+++ b/examples/ac-dc-meshed/ac-dc-lpf.py
@@ -53,7 +53,7 @@
     p0 = 0.
     p1 = 0.
 
-    for c in network.iterate_components(pypsa.components.branch_components):
+    for c in network.iterate_components(network.branch_components):
 
         bs = (c.df.bus0 == bus)
 
diff --git a/examples/opf-storage-hvdc/opf-storage.py b/examples/opf-storage-hvdc/opf-storage.py
index c842e4dcc..d045156c0 100644
--- a/examples/opf-storage-hvdc/opf-storage.py
+++ b/examples/opf-storage-hvdc/opf-storage.py
@@ -105,7 +105,7 @@
         p0 = 0.
         p1 = 0.
 
-        for c in network.iterate_components(pypsa.components.branch_components):
+        for c in network.iterate_components(network.branch_components):
 
             bs = (c.df.bus0 == bus)
 
diff --git a/pypsa/components.py b/pypsa/components.py
index 064705d0b..77094e0c5 100644
--- a/pypsa/components.py
+++ b/pypsa/components.py
@@ -290,7 +290,7 @@ def __init__(self, import_name=None, name="", ignore_standard_types=False,
     def _build_dataframes(self):
         """Function called when network is created to build component pandas.DataFrames."""
 
-        for component in all_components:
+        for component in self.all_components:
 
             attrs = self.components[component]["attrs"]
 
@@ -314,7 +314,7 @@ def _build_dataframes(self):
 
     def read_in_default_standard_types(self):
 
-        for std_type in standard_types:
+        for std_type in self.standard_type_components:
 
             list_name = self.components[std_type]["list_name"]
 
@@ -383,7 +383,7 @@ def set_snapshots(self,snapshots):
         if isinstance(snapshots, pd.DatetimeIndex) and _pd_version < '0.18.0':
             snapshots = pd.Index(snapshots.values)
 
-        for component in all_components:
+        for component in self.all_components:
             pnl = self.pnl(component)
             attrs = self.components[component]["attrs"]
 
@@ -615,10 +615,10 @@ def copy(self, with_time=True, ignore_standard_types=False):
 
         network = self.__class__(ignore_standard_types=ignore_standard_types)
 
-        for component in self.iterate_components(["Bus", "Carrier"] + sorted(all_components - {"Bus","Carrier"})):
+        for component in self.iterate_components(["Bus", "Carrier"] + sorted(self.all_components - {"Bus","Carrier"})):
             df = component.df
             #drop the standard types to avoid them being read in twice
-            if not ignore_standard_types and component.name in standard_types:
+            if not ignore_standard_types and component.name in self.standard_type_components:
                 df = component.df.drop(network.components[component.name]["standard_types"].index)
 
             import_components_from_dataframe(network, df, component.name)
@@ -676,24 +676,24 @@ def __getitem__(self, key):
         )
         buses_i = n.buses.index
 
-        rest_components = all_components - standard_types - one_port_components - branch_components
+        rest_components = self.all_components - self.standard_type_components - self.one_port_components - self.branch_components
         for c in rest_components - {"Bus", "SubNetwork"}:
             n.import_components_from_dataframe(pd.DataFrame(self.df(c)), c)
 
-        for c in standard_types:
+        for c in self.standard_type_components:
             df = self.df(c).drop(self.components[c]["standard_types"].index)
             n.import_components_from_dataframe(pd.DataFrame(df), c)
 
-        for c in one_port_components:
+        for c in self.one_port_components:
             df = self.df(c).loc[lambda df: df.bus.isin(buses_i)]
             n.import_components_from_dataframe(pd.DataFrame(df), c)
 
-        for c in branch_components:
+        for c in self.branch_components:
             df = self.df(c).loc[lambda df: df.bus0.isin(buses_i) & df.bus1.isin(buses_i)]
             n.import_components_from_dataframe(pd.DataFrame(df), c)
 
         n.set_snapshots(self.snapshots[time_i])
-        for c in all_components:
+        for c in self.all_components:
             i = n.df(c).index
             try:
                 npnl = n.pnl(c)
@@ -716,23 +716,23 @@ def __getitem__(self, key):
     #beware, this turns bools like s_nom_extendable into objects because of
     #presence of links without s_nom_extendable
     def branches(self):
-        return pd.concat((self.df(c) for c in branch_components),
-                         keys=branch_components)
+        return pd.concat((self.df(c) for c in self.branch_components),
+                         keys=self.branch_components)
 
     def passive_branches(self):
-        return pd.concat((self.df(c) for c in passive_branch_components),
-                         keys=passive_branch_components)
+        return pd.concat((self.df(c) for c in self.passive_branch_components),
+                         keys=self.passive_branch_components)
 
     def controllable_branches(self):
-        return pd.concat((self.df(c) for c in controllable_branch_components),
-                         keys=controllable_branch_components)
+        return pd.concat((self.df(c) for c in self.controllable_branch_components),
+                         keys=self.controllable_branch_components)
 
     def determine_network_topology(self):
         """
         Build sub_networks from topology.
         """
 
-        adjacency_matrix = self.adjacency_matrix(passive_branch_components)
+        adjacency_matrix = self.adjacency_matrix(self.passive_branch_components)
         n_components, labels = csgraph.connected_components(adjacency_matrix, directed=False)
 
         # remove all old sub_networks
@@ -761,12 +761,12 @@ def determine_network_topology(self):
 
         self.buses.loc[:, "sub_network"] = labels.astype(str)
 
-        for c in self.iterate_components(passive_branch_components):
+        for c in self.iterate_components(self.passive_branch_components):
             c.df["sub_network"] = c.df.bus0.map(self.buses["sub_network"])
 
     def iterate_components(self, components=None, skip_empty=True):
         if components is None:
-            components = all_components
+            components = self.all_components
 
         return (Component(name=c,
                           list_name=self.components[c]["list_name"],
@@ -790,13 +790,13 @@ def consistency_check(self):
         """
 
 
-        for c in self.iterate_components(one_port_components):
+        for c in self.iterate_components(self.one_port_components):
             missing = c.df.index[~c.df.bus.isin(self.buses.index)]
             if len(missing) > 0:
                 logger.warning("The following %s have buses which are not defined:\n%s",
                                c.list_name, missing)
 
-        for c in self.iterate_components(branch_components):
+        for c in self.iterate_components(self.branch_components):
             for attr in ["bus0","bus1"]:
                 missing = c.df.index[~c.df[attr].isin(self.buses.index)]
                 if len(missing) > 0:
@@ -804,7 +804,7 @@ def consistency_check(self):
                                    c.list_name, attr, missing)
 
 
-        for c in self.iterate_components(passive_branch_components):
+        for c in self.iterate_components(self.passive_branch_components):
             for attr in ["x","r"]:
                 bad = c.df.index[c.df[attr] == 0.]
                 if len(bad) > 0:
@@ -824,7 +824,7 @@ def consistency_check(self):
                                c.list_name, bad)
 
 
-        for c in self.iterate_components(all_components):
+        for c in self.iterate_components(self.all_components):
             for attr in c.attrs.index[c.attrs.varying & c.attrs.static]:
                 attr_df = c.pnl[attr]
 
@@ -845,7 +845,7 @@ def consistency_check(self):
 
         static_attrs = ['p_nom', 's_nom', 'e_nom']
         varying_attrs = ['p_max_pu', 'e_max_pu']
-        for c in self.iterate_components(all_components - {'TransformerType'}):
+        for c in self.iterate_components(self.all_components - {'TransformerType'}):
             varying_attr = c.attrs.index[c.attrs.varying].intersection(varying_attrs)
             static_attr = c.attrs.index[c.attrs.static].intersection(static_attrs)
 
@@ -958,7 +958,7 @@ def transformers_i(self):
     def branches_i(self):
         types = []
         names = []
-        for c in self.iterate_components(passive_branch_components):
+        for c in self.iterate_components(self.network.passive_branch_components):
             types += len(c.ind) * [c.name]
             names += list(c.ind)
         return pd.MultiIndex.from_arrays([types, names], names=('type', 'name'))
@@ -1008,17 +1008,3 @@ def iterate_components(self, components=None, skip_empty=True):
             c = Component(*c[:-1], ind=getattr(self, c.list_name + '_i')())
             if not (skip_empty and len(c.ind) == 0):
                 yield c
-
-
-standard_types = {"LineType", "TransformerType"}
-
-passive_one_port_components = {"ShuntImpedance"}
-controllable_one_port_components = {"Load", "Generator", "StorageUnit", "Store"}
-one_port_components = passive_one_port_components|controllable_one_port_components
-
-passive_branch_components = {"Line", "Transformer"}
-controllable_branch_components = {"Link"}
-branch_components = passive_branch_components|controllable_branch_components
-
-#i.e. everything except "Network"
-all_components = branch_components|one_port_components|standard_types|{"Bus", "SubNetwork", "Carrier", "GlobalConstraint"}
diff --git a/pypsa/contingency.py b/pypsa/contingency.py
index d2198a984..ba688a11a 100644
--- a/pypsa/contingency.py
+++ b/pypsa/contingency.py
@@ -103,8 +103,6 @@ def network_lpf_contingency(network, snapshots=None, branch_outages=None):
 
     """
 
-    from .components import passive_branch_components
-
     if snapshots is None:
         snapshots = network.snapshots
 
@@ -126,7 +124,7 @@ def network_lpf_contingency(network, snapshots=None, branch_outages=None):
 
     p0_base = pd.Series(index=passive_branches.index)
 
-    for c in passive_branch_components:
+    for c in network.passive_branch_components:
         pnl = network.pnl(c)
         p0_base[c] = pnl.p0.loc[snapshot]
 
diff --git a/pypsa/graph.py b/pypsa/graph.py
index d56d134c0..fe4d3baf6 100644
--- a/pypsa/graph.py
+++ b/pypsa/graph.py
@@ -29,11 +29,11 @@ def graph(network, branch_components=None, weight=None):
 
     if isinstance(network, components.Network):
         if branch_components is None:
-            branch_components = components.branch_components
+            branch_components = network.branch_components
         buses_i = network.buses.index
     elif isinstance(network, components.SubNetwork):
         if branch_components is None:
-            branch_components = components.passive_branch_components
+            branch_components = network.network.passive_branch_components
         buses_i = network.buses_i()
     else:
         raise TypeError("build_graph must be called with a Network or a SubNetwork")
@@ -85,12 +85,12 @@ def adjacency_matrix(network, branch_components=None, busorder=None, weights=Non
 
     if isinstance(network, components.Network):
         if branch_components is None:
-            branch_components = components.branch_components
+            branch_components = network.branch_components
         if busorder is None:
             busorder = network.buses.index
     elif isinstance(network, components.SubNetwork):
         if branch_components is None:
-            branch_components = components.passive_branch_components
+            branch_components = network.network.passive_branch_components
         if busorder is None:
             busorder = network.buses_i()
     else:
@@ -146,12 +146,12 @@ def incidence_matrix(network, branch_components=None, busorder=None):
 
     if isinstance(network, components.Network):
         if branch_components is None:
-            branch_components = components.branch_components
+            branch_components = network.branch_components
         if busorder is None:
             busorder = network.buses.index
     elif isinstance(network, components.SubNetwork):
         if branch_components is None:
-            branch_components = components.passive_branch_components
+            branch_components = network.network.passive_branch_components
         if busorder is None:
             busorder = network.buses_i()
     else:
diff --git a/pypsa/io.py b/pypsa/io.py
index 5ae00909a..a1f773124 100644
--- a/pypsa/io.py
+++ b/pypsa/io.py
@@ -288,7 +288,7 @@ def _export_to_exporter(network, exporter, basename, export_standard_types=False
     exporter.save_snapshots(snapshots)
 
     exported_components = []
-    for component in pypsa.components.all_components - {"SubNetwork"}:
+    for component in network.all_components - {"SubNetwork"}:
 
         list_name = network.components[component]["list_name"]
         attrs = network.components[component]["attrs"]
@@ -296,7 +296,7 @@ def _export_to_exporter(network, exporter, basename, export_standard_types=False
         df = network.df(component)
         pnl = network.pnl(component)
 
-        if not export_standard_types and component in pypsa.components.standard_types:
+        if not export_standard_types and component in network.standard_type_components:
             df = df.drop(network.components[component]["standard_types"].index)
 
         # first do static attributes
@@ -538,7 +538,7 @@ def _import_from_importer(network, importer, basename, skip_time=False):
     imported_components = []
 
     # now read in other components; make sure buses and carriers come first
-    for component in ["Bus", "Carrier"] + sorted(pypsa.components.all_components - {"Bus", "Carrier", "SubNetwork"}):
+    for component in ["Bus", "Carrier"] + sorted(network.all_components - {"Bus", "Carrier", "SubNetwork"}):
         list_name = network.components[component]["list_name"]
 
         df = importer.get_static(list_name)
diff --git a/pypsa/networkclustering.py b/pypsa/networkclustering.py
index 0131851ef..3cb784298 100644
--- a/pypsa/networkclustering.py
+++ b/pypsa/networkclustering.py
@@ -220,7 +220,7 @@ def get_clustering_from_busmap(network, busmap, with_time=True, line_length_fact
     if with_time:
         network_c.set_snapshots(network.snapshots)
 
-    one_port_components = components.one_port_components.copy()
+    one_port_components = network.one_port_components.copy()
 
     if aggregate_generators_weighted:
         one_port_components.remove("Generator")
diff --git a/pypsa/opf.py b/pypsa/opf.py
index 6ef07a5cb..ddf401993 100644
--- a/pypsa/opf.py
+++ b/pypsa/opf.py
@@ -866,14 +866,12 @@ def define_passive_branch_flows_with_kirchhoff(network,snapshots,skip_vars=False
 
 def define_passive_branch_constraints(network,snapshots):
 
-    from .components import passive_branch_components
-
     passive_branches = network.passive_branches()
     extendable_branches = passive_branches[passive_branches.s_nom_extendable]
     fixed_branches = passive_branches[~ passive_branches.s_nom_extendable]
 
     s_max_pu = pd.concat({c : get_switchable_as_dense(network,c,'s_max_pu')
-                          for c in passive_branch_components}, axis=1)
+                          for c in network.passive_branch_components}, axis=1)
 
     flow_upper = {(b[0],b[1],sn) : [[(1,network.model.passive_branch_p[b[0],b[1],sn])],
                                     "<=", s_max_pu.at[sn,b]*fixed_branches.at[b,"s_nom"]]
@@ -1123,9 +1121,6 @@ def define_linear_objective(network,snapshots):
 
 def extract_optimisation_results(network, snapshots, formulation="angles"):
 
-    from .components import \
-        passive_branch_components, branch_components, controllable_one_port_components
-
     if isinstance(snapshots, pd.DatetimeIndex) and _pd_version < '0.18.0':
         # Work around pandas bug #12050 (https://github.com/pydata/pandas/issues/12050)
         snapshots = pd.Index(snapshots.values)
@@ -1181,14 +1176,14 @@ def set_from_series(df, series):
             pd.concat({c.name:
                        c.pnl.p.loc[snapshots].multiply(c.df.sign, axis=1)
                        .groupby(c.df.bus, axis=1).sum()
-                       for c in network.iterate_components(controllable_one_port_components)}) \
+                       for c in network.iterate_components(network.controllable_one_port_components)}) \
               .sum(level=1) \
               .reindex(columns=network.buses_t.p.columns, fill_value=0.)
 
 
     # passive branches
     passive_branches = as_series(model.passive_branch_p)
-    for c in network.iterate_components(passive_branch_components):
+    for c in network.iterate_components(network.passive_branch_components):
         set_from_series(c.pnl.p0, passive_branches.loc[c.name])
         c.pnl.p1.loc[snapshots] = - c.pnl.p0.loc[snapshots]
 
@@ -1262,7 +1257,7 @@ def set_from_series(df, series):
 
 
     s_nom_extendable_passive_branches = as_series(model.passive_branch_s_nom)
-    for c in network.iterate_components(passive_branch_components):
+    for c in network.iterate_components(network.passive_branch_components):
         c.df['s_nom_opt'] = c.df.s_nom
         if c.df.s_nom_extendable.any():
             c.df.loc[c.df.s_nom_extendable, 's_nom_opt'] = s_nom_extendable_passive_branches.loc[c.name]
diff --git a/pypsa/opt.py b/pypsa/opt.py
index 0fe9998b3..fb1a4cc97 100644
--- a/pypsa/opt.py
+++ b/pypsa/opt.py
@@ -334,10 +334,9 @@ def empty_model(model):
 @contextmanager
 def empty_network(network):
     logger.debug("Storing pypsa timeseries to disk")
-    from .components import all_components
 
     panels = {}
-    for c in all_components:
+    for c in network.all_components:
         attr = network.components[c]["list_name"] + "_t"
         panels[attr] = getattr(network, attr)
         setattr(network, attr, None)
diff --git a/pypsa/pf.py b/pypsa/pf.py
index 3e4360d07..fc2a4cf18 100644
--- a/pypsa/pf.py
+++ b/pypsa/pf.py
@@ -208,8 +208,6 @@ def sub_network_pf(sub_network, snapshots=None, skip_pre=False, x_tol=1e-6, use_
     # _sub_network_prepare_pf(sub_network, snapshots, skip_pre, calculate_Y)
     network = sub_network.network
 
-    from .components import passive_branch_components, controllable_branch_components, controllable_one_port_components
-
     if not skip_pre:
         calculate_dependent_values(network)
         find_bus_controls(sub_network)
@@ -225,7 +223,7 @@ def sub_network_pf(sub_network, snapshots=None, skip_pre=False, x_tol=1e-6, use_
 
     for n in ("q", "p"):
         # allow all one ports to dispatch as set
-        for c in sub_network.iterate_components(controllable_one_port_components):
+        for c in sub_network.iterate_components(network.controllable_one_port_components):
             c_n_set = get_switchable_as_dense(network, c.name, n + '_set', snapshots, c.ind)
             c.pnl[n].loc[snapshots, c.ind] = c_n_set
 
@@ -234,13 +232,13 @@ def sub_network_pf(sub_network, snapshots=None, skip_pre=False, x_tol=1e-6, use_
             sum([((c.pnl[n].loc[snapshots, c.ind] * c.df.loc[c.ind, 'sign'])
                   .groupby(c.df.loc[c.ind, 'bus'], axis=1).sum()
                   .reindex(columns=buses_o, fill_value=0.))
-                 for c in sub_network.iterate_components(controllable_one_port_components)])
+                 for c in sub_network.iterate_components(network.controllable_one_port_components)])
 
         if n == "p":
             network.buses_t[n].loc[snapshots, buses_o] += sum(
                 [(- c.pnl[n+str(i)].loc[snapshots].groupby(c.df["bus"+str(i)], axis=1).sum()
                   .reindex(columns=buses_o, fill_value=0))
-                 for c in network.iterate_components(controllable_branch_components)
+                 for c in network.iterate_components(network.controllable_branch_components)
                  for i in [0,1]])
 
     def f(guess):
@@ -338,7 +336,7 @@ def dfdx(guess):
     #add voltages to branches
     buses_indexer = buses_o.get_indexer
     branch_bus0 = []; branch_bus1 = []
-    for c in sub_network.iterate_components(passive_branch_components):
+    for c in sub_network.iterate_components(network.passive_branch_components):
         branch_bus0 += list(c.df.loc[c.ind, 'bus0'])
         branch_bus1 += list(c.df.loc[c.ind, 'bus1'])
     v0 = V[:,buses_indexer(branch_bus0)]
@@ -352,7 +350,7 @@ def dfdx(guess):
 
     s0 = pd.DataFrame(v0*np.conj(i0), columns=branches_i, index=snapshots)
     s1 = pd.DataFrame(v1*np.conj(i1), columns=branches_i, index=snapshots)
-    for c in sub_network.iterate_components(passive_branch_components):
+    for c in sub_network.iterate_components(network.passive_branch_components):
         s0t = s0.loc[:,c.name]
         s1t = s1.loc[:,c.name]
         c.pnl.p0.loc[snapshots,s0t.columns] = s0t.values.real
@@ -610,8 +608,6 @@ def find_bus_controls(sub_network):
 def calculate_B_H(sub_network,skip_pre=False):
     """Calculate B and H matrices for AC or DC sub-networks."""
 
-    from .components import passive_branch_components
-
     network = sub_network.network
 
     if not skip_pre:
@@ -627,7 +623,7 @@ def calculate_B_H(sub_network,skip_pre=False):
 
     #susceptances
     b = 1./np.concatenate([(c.df.loc[c.ind, attribute]).values \
-                           for c in sub_network.iterate_components(passive_branch_components)])
+                           for c in sub_network.iterate_components(network.passive_branch_components)])
 
 
     if np.isnan(b).any():
@@ -645,7 +641,7 @@ def calculate_B_H(sub_network,skip_pre=False):
 
     sub_network.p_branch_shift = -b*np.concatenate([(c.df.loc[c.ind, "phase_shift"]).values*np.pi/180. if c.name == "Transformer"
                                                     else np.zeros((len(c.ind),))
-                                                    for c in sub_network.iterate_components(passive_branch_components)])
+                                                    for c in sub_network.iterate_components(network.passive_branch_components)])
 
     sub_network.p_bus_shift = sub_network.K * sub_network.p_branch_shift
 
@@ -916,10 +912,6 @@ def sub_network_lpf(sub_network, snapshots=None, skip_pre=False):
     logger.info("Performing linear load-flow on %s sub-network %s for snapshot(s) %s",
                 sub_network.network.sub_networks.at[sub_network.name,"carrier"], sub_network, snapshots)
 
-    from .components import \
-        one_port_components, controllable_one_port_components, \
-        passive_branch_components, controllable_branch_components
-
     network = sub_network.network
 
 
@@ -939,7 +931,7 @@ def sub_network_lpf(sub_network, snapshots=None, skip_pre=False):
         network.shunt_impedances.g_pu.loc[shunt_impedances_i].values
 
     # allow all one ports to dispatch as set
-    for c in sub_network.iterate_components(controllable_one_port_components):
+    for c in sub_network.iterate_components(network.controllable_one_port_components):
         c_p_set = get_switchable_as_dense(network, c.name, 'p_set', snapshots, c.ind)
         c.pnl.p.loc[snapshots, c.ind] = c_p_set
 
@@ -948,11 +940,11 @@ def sub_network_lpf(sub_network, snapshots=None, skip_pre=False):
         sum([((c.pnl.p.loc[snapshots, c.ind] * c.df.loc[c.ind, 'sign'])
               .groupby(c.df.loc[c.ind, 'bus'], axis=1).sum()
               .reindex(columns=buses_o, fill_value=0.))
-             for c in sub_network.iterate_components(one_port_components)]
+             for c in sub_network.iterate_components(network.one_port_components)]
             +
             [(- c.pnl["p"+str(i)].loc[snapshots].groupby(c.df["bus"+str(i)], axis=1).sum()
               .reindex(columns=buses_o, fill_value=0))
-             for c in network.iterate_components(controllable_branch_components)
+             for c in network.iterate_components(network.controllable_branch_components)
              for i in [0,1]])
 
     if not skip_pre and len(branches_i) > 0:
@@ -965,7 +957,7 @@ def sub_network_lpf(sub_network, snapshots=None, skip_pre=False):
         flows = pd.DataFrame(v_diff * sub_network.H.T,
                              columns=branches_i, index=snapshots) + sub_network.p_branch_shift
 
-        for c in sub_network.iterate_components(passive_branch_components):
+        for c in sub_network.iterate_components(network.passive_branch_components):
             f = flows.loc[:, c.name]
             c.pnl.p0.loc[snapshots, f.columns] = f
             c.pnl.p1.loc[snapshots, f.columns] = -f
diff --git a/test/test_pf_against_pypower.py b/test/test_pf_against_pypower.py
index a92c9ca00..f6ebc32e2 100644
--- a/test/test_pf_against_pypower.py
+++ b/test/test_pf_against_pypower.py
@@ -55,7 +55,7 @@ def test_pypower_case():
     network.pf()
 
     #compare branch flows
-    for c in network.iterate_components(pypsa.components.passive_branch_components):
+    for c in network.iterate_components(network.passive_branch_components):
         for si in ["p0","p1","q0","q1"]:
             si_pypsa = getattr(c.pnl,si).loc["now"].values
             si_pypower = results_df['branch'][si][c.df.original_index].values