NonReturnValveController created, test in pipeflow_internals added and docu updated

doc/source/controller/controller_classes.rst

@@ -22,4 +22,15 @@ This is used to read the data from a DataSource and write it to a network.
 
 .. _ConstControl:
 .. autoclass:: pandapower.control.controller.const_control.ConstControl
-    :members:
+    :members:
+
+NonReturnValveController
+========================
+
+The NonReturnValveController makes it possible to implement a valve
+which only allows flow in the connection direction. In the backward
+direction the valve can be regarded as ideally closed.
+
+.. _NonReturnValveController:
+.. autoclass:: pandapipes.control.controller.non_return_valve_controller.NonReturnValveController
+    :members:

pandapipes/control/__init__.py

@@ -3,3 +3,4 @@
 # Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
 
 from pandapipes.control.run_control import run_control
+from pandapipes.control.controller.non_return_valve_controller import NonReturnValveController

pandapipes/control/controller/non_return_valve_controller.py

@@ -0,0 +1,118 @@
+# Copyright (c) 2020 by Fraunhofer Institute for Energy Economics
+# and Energy System Technology (IEE), Kassel. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
+
+import pandapipes as pp
+import numpy
+from pandapower.control.basic_controller import Controller
+
+try:
+    import pplog as logging
+except ImportError:
+    import logging
+
+logger = logging.getLogger(__name__)
+
+
+class NonReturnValveController(Controller):
+    """
+    Controller for implementing a non-return valve.
+
+    :param net: The net in which the controller resides
+    :type net: pandapipesNet
+    :param element_index: IDs of controlled valves
+    :type element_index: int[]
+    :param in_service: Indicates if the controller is currently in_service
+    :type in_service: bool, default True
+    :param recycle: Re-use of internal-data
+    :type recycle: bool, default True
+    :param drop_same_existing_ctrl: Indicates if already existing controllers of the same type and with the same matching parameters (e.g. at same element) should be dropped
+    :type drop_same_existing_ctrl: bool, default False
+    :param kwargs: Parameters for pipeflow
+    :type kwargs: dict
+
+    :Example:
+        >>> kwargs = {'stop_condition': 'tol', 'iter': 100, 'tol_p': 1e-7, 'tol_v': 1e-7, 'friction_model': 'colebrook',
+        >>>           'mode': 'hydraulics', 'only_update_hydraulic_matrix': False}
+        >>> NonReturnValveController(net, element_index=[0, 1, 3], **kwargs)
+        >>> run_control(net)
+
+    """
+
+    def __init__(self, net, element_index, profile_name=None,
+                 scale_factor=1.0, in_service=True, recycle=True, order=0, level=0,
+                 drop_same_existing_ctrl=False, set_q_from_cosphi=False, matching_params=None, initial_pipeflow=False,
+                 **kwargs):
+
+        if matching_params is None:
+            matching_params = {"element_index": element_index}
+
+        # just calling init of the parent
+        super().__init__(net, in_service=in_service, recycle=recycle, order=order, level=level,
+                         drop_same_existing_ctrl=drop_same_existing_ctrl,
+                         matching_params=matching_params, initial_powerflow=initial_pipeflow,
+                         **kwargs)
+
+        self.matching_params = {"element_index": element_index}
+        if numpy.isscalar(element_index):
+            self.element_index = [element_index]
+        else:
+            self.element_index = element_index
+        self.values = None
+        self.profile_name = profile_name
+        self.scale_factor = scale_factor
+        self.initial_pipeflow = initial_pipeflow
+        self.kwargs = kwargs
+        self.v_m_per_s = []  # current flow velocities at valves
+        self.opened = []  # remember original user-defined values of opened
+
+        if set_q_from_cosphi:
+            logger.error("Parameter set_q_from_cosphi deprecated!")
+            raise ValueError
+
+    def initialize_control(self):
+        """
+        First calculation of a pipeflow. \n
+        Saving the user-defined values, determine valves with negative flow velocities,
+        set opened to False for these.
+        """
+        pp.pipeflow(self.net, self.kwargs)
+
+        self.opened = self.net.valve.loc[self.element_index, "opened"]
+
+        j = 0
+        for i in self.element_index:
+            self.v_m_per_s.append(self.net.res_valve.loc[i, "v_mean_m_per_s"])
+
+            if self.net.valve.loc[i, "opened"] and self.v_m_per_s[j] < 0:
+                # use the element indices, where opened = True, otherwise NaN would be in self.v_m_per_s
+                self.net.valve.loc[i, "opened"] = False
+            j += 1
+
+    def is_converged(self):
+        """
+        Convergence Condition: If all flow velocities at the non-return valves are >= 0 or opened equal False. \n
+        Resetting the variable opened to user defaults.
+        """
+
+        for i in range(len(self.element_index)):
+            if self.net.valve.loc[self.element_index[i], "opened"] and self.v_m_per_s[i] < 0:
+                return False
+
+        self.net.valve.loc[self.element_index, "opened"] = self.opened
+        return True
+
+    def control_step(self):
+        """
+        Check whether negative flow velocities are still present at non-return valves.
+        """
+        pp.pipeflow(self.net, self.kwargs)
+
+        j = 0
+        for i in self.element_index:
+            self.v_m_per_s.append(self.net.res_valve.loc[i, "v_mean_m_per_s"])
+
+            if self.net.valve.loc[i, "opened"] and self.v_m_per_s[j] < 0:
+                # use the element indices, where opened = True, otherwise NaN would be in self.v_m_per_s
+                self.net.valve.loc[i, "opened"] = False
+            j += 1

pandapipes/test/pipeflow_internals/test_non_return_valve_controller.py

@@ -0,0 +1,44 @@
+# Copyright (c) 2020 by Fraunhofer Institute for Energy Economics
+# and Energy System Technology (IEE), Kassel. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
+
+import pandapipes
+import pytest
+from pandapipes.control import NonReturnValveController, run_control
+
+
+def test_nrv():
+    net = pandapipes.create_empty_network("net", fluid="water", add_stdtypes=True)
+
+    j0 = pandapipes.create_junction(net, pn_bar=3, tfluid_k=293.15)
+    j1 = pandapipes.create_junction(net, pn_bar=3, tfluid_k=293.15)
+    j2 = pandapipes.create_junction(net, pn_bar=3, tfluid_k=293.15)
+    j3 = pandapipes.create_junction(net, pn_bar=3, tfluid_k=283.15)
+    j4 = pandapipes.create_junction(net, pn_bar=3, tfluid_k=283.15)
+
+    pandapipes.create_ext_grid(net, j0, p_bar=3, t_k=293.15, type="pt")
+
+    pandapipes.create_sink(net, j1, mdot_kg_per_s=1)
+    pandapipes.create_sink(net, j4, mdot_kg_per_s=0.5)
+
+    pandapipes.create_source(net, j2, mdot_kg_per_s=0.05)
+    pandapipes.create_source(net, j3, mdot_kg_per_s=1)
+
+    pandapipes.create_pipe_from_parameters(net, j1, j0, diameter_m=0.75, k_mm=0.1, length_km=15)
+    pandapipes.create_pipe_from_parameters(net, j4, j2, diameter_m=0.1, k_mm=0.1, length_km=10)
+
+    pandapipes.create_valve(net, j4, j3, diameter_m=0.1, opened=True)
+    pandapipes.create_valve(net, j1, j3, diameter_m=0.07, opened=True)
+    pandapipes.create_valve(net, j1, j2, diameter_m=0.05, opened=True)
+    pandapipes.create_valve(net, j3, j0, diameter_m=0.01, opened=True)
+
+    kwargs = {'stop_condition': 'tol', 'iter': 100, 'tol_p': 1e-7, 'tol_v': 1e-7, 'friction_model': 'colebrook',
+              'mode': 'hydraulics', 'only_update_hydraulic_matrix': False}
+
+    NonReturnValveController(net, element_index=[1, 3], **kwargs)
+
+    run_control(net)
+
+
+if __name__ == "__main__":
+    pytest.main([r'pandapipes/test/pipeflow_internals/test_non_return_valve_controller.py'])