Fix the examples by proper initialisation and protection

Introduces a small flow rate epsilon to avoid division by zero when calculating blade angles at zero flow.
Adds a conditional check for total turbine power to prevent division by zero when computing efficiency.

Author: dietmarw

OpenHPL/ElectroMech/Generators/SynchGen.mo

@@ -35,6 +35,8 @@ model SynchGen "Simple model of the generator connected to the grid"
     Dialog(group = "Mechanical part"));
   parameter Real k_b = 1000 "Friction factor in the generator bearing box, W*s3/rad3" annotation (
     Dialog(group = "Mechanical part"));
+  parameter SI.AngularVelocity w_min = Wm_op * 1e-3 "Minimum angular velocity to prevent division by zero" annotation (
+    Dialog(group = "Mechanical part"));
   parameter Boolean UseFrequencyOutput = true "If checked - get a connector for frequency output" annotation (
     choices(checkBox = true),
     Dialog(group = "Network")), SelfInitialization = false "If checked - specify initial values" annotation (
@@ -89,7 +91,7 @@ equation
   Vt = sqrt((EEd - Ra * Id - xxq * Iq) ^ 2 + (EEq - Ra * Iq + xxd * Id) ^ 2);
   It = sqrt(Id ^ 2 + Iq ^ 2);
   Pe = 3 * (EEd * Id + EEq * Iq);
-  Qe = sqrt(9 * Vt ^ 2 * It ^ 2 - Pe ^ 2);
+  Qe = sqrt(noEvent(max(9 * Vt ^ 2 * It ^ 2 - Pe ^ 2, 0)));
   // dynamic equations
   TTqo * der(EEd) = (-EEd) + (xxq - xq) * Iq;
   TTdo * der(EEq) = (-EEq) + (xd - xxd) * Id + Ef;
@@ -105,7 +107,7 @@ equation
   der(Vstabilizer) = ((-Vstabilizer) + KF * der(Ef)) / TFE;
   // Mechanical equation
   W_fa = 0.5 * k_b * w ^ 2;
-  der(w) = (Wdot_ts - Pe) / (J * w);
+  der(w) = (Wdot_ts - Pe) / (J * noEvent(max(w, w_min)));
   // - W_fa;
   //
   annotation (preferredView="info",

OpenHPL/ElectroMech/Turbines/Francis.mo

@@ -85,6 +85,7 @@ model Francis "Model of the Francis turbine"
                                 Placement(transformation(origin={-120,-80}, extent={{-20,-20},
       {20,20}})));
 protected
+  parameter SI.VolumeFlowRate Vdot_eps = Vdot_n * 1e-4 "Small flow rate to regularize equations at zero flow";
   Modelica.Blocks.Interfaces.RealOutput p_out = Wdot_s "Internal connector for output power" annotation (Placement(transformation(
         extent={{-10,-10},{10,10}},
         rotation=90,
@@ -197,16 +198,16 @@ equation
     alpha1 = phi - psi;
   // Blade angles relation
     cot_a1 = 1 / Modelica.Math.tan(alpha1);
-    cot_a2 = cot_b2 + w * R_2 / (Vdot / A_2);
+    cot_a2 = cot_b2 + w * R_2 / (noEvent(max(Vdot, Vdot_eps)) / A_2);
     cot_b1 =1/Modelica.Math.tan(Modelica.Units.Conversions.from_deg(beta1));
     cot_b2 =1/Modelica.Math.tan(Modelica.Units.Conversions.from_deg(beta2));
-    cot_g1 = cot_a1 - w * R_1 / (Vdot / A_1);
+    cot_g1 = cot_a1 - w * R_1 / (noEvent(max(Vdot, Vdot_eps)) / A_1);
   // pressure drop through the turbine
-    dp_r * Vdot + 0.5 * mdot * Vdot ^ 2 * (1 / A_0 ^ 2 - 1 / A_2 ^ 2) = Wdot_t;
+    dp_r * noEvent(max(Vdot, Vdot_eps)) + 0.5 * mdot * Vdot ^ 2 * (1 / A_0 ^ 2 - 1 / A_2 ^ 2) = Wdot_t;
     Wdot_t = Wdot_s + Wdot_ft;
     dp_r = p_r1 - p_tr2;
   // turbine efficiency
-    coef = Wdot_s / Wdot_t;
+    coef = if noEvent(abs(Wdot_t) > 1e-6) then Wdot_s / Wdot_t else 0;
   // connectors
     p_tr2 = o.p;
     i.mdot+o.mdot=0;

…mples/WithOpenIPSL/DetailedGenFrancis.mo …HPL/Examples/WithOpenIPSL/DetailedGen.moOpenHPL/Examples/WithOpenIPSL/DetailedGenFrancis.mo renamed to OpenHPL/Examples/WithOpenIPSL/DetailedGen.mo OpenHPL/Examples/WithOpenIPSL/DetailedGenFrancis.mo renamed to OpenHPL/Examples/WithOpenIPSL/DetailedGen.mo

@@ -1,8 +1,8 @@
 within OpenHPL.Examples.WithOpenIPSL;
-model DetailedGenFrancis
-  extends SimpleGenFrancis(redeclare Waterway.PenstockKP penstock(
+model DetailedGen
+  extends SimpleGen(       redeclare Waterway.PenstockKP penstock(
       vertical=true,
       H=428.5,
       D_i=3), data(SteadyState=false));
   annotation (experiment(StopTime=2000));
-end DetailedGenFrancis;
+end DetailedGen;

OpenHPL/Examples/WithOpenIPSL/SimpleGen.mo

@@ -0,0 +1,80 @@
+within OpenHPL.Examples.WithOpenIPSL;
+model SimpleGen "Synergy with OpenIPSL library(generator)"
+  extends Modelica.Icons.Example;
+  extends OpenIPSL.Tests.BaseClasses.MachineTestBase(pwLine2(displayPF=true), pwLine1(displayPF=true));
+  OpenHPL.Waterway.Reservoir reservoir(h_0=48,
+    fixElevation=true,
+    z_0=500)                                   annotation (Placement(transformation(
+        origin={-80,-80},
+        extent={{-10,-10},{10,10}})));
+  OpenHPL.Waterway.Pipe intake(H=23, D_i=3)
+                                     annotation (Placement(transformation(extent={{-66,-90},{-46,-70}})));
+  OpenHPL.Waterway.Pipe discharge(L=600, H=0.5) annotation (Placement(transformation(extent={{48,-90},{68,-70}})));
+  OpenHPL.Waterway.Reservoir tail(h_0=5) annotation (Placement(transformation(
+        origin={84,-80},
+        extent={{-10,10},{10,-10}},
+        rotation=180)));
+  replaceable
+  Waterway.Pipe penstock(
+    vertical=true,
+    L=600,
+    H=428.5,
+    D_i=3) constrainedby Interfaces.TwoContacts
+           annotation (Placement(transformation(
+        origin={0,-80},
+        extent={{-10,-10},{10,10}})));
+  OpenHPL.Waterway.SurgeTank surgeTank(h_0=70.939) annotation (Placement(transformation(
+        origin={-30,-80},
+        extent={{-10,-10},{10,10}})));
+  ElectroMech.Turbines.Turbine         turbine(
+    H_n=460,
+    Vdot_n=24.3,
+    Pmax(displayUnit="MW") = 125000000,
+    enable_P_out=true)
+              annotation (Placement(transformation(
+        origin={32,-80},
+        extent={{-10,-10},{10,10}})));
+  inner OpenHPL.Data data(SteadyState=true, Vdot_0=4.49)
+                                       annotation (Placement(transformation(
+        origin={-90,70},
+        extent={{-10,-10},{10,10}})));
+  OpenIPSL.Electrical.Machines.PSAT.Order2 generator(
+    D=0,
+    M=10,
+    P_0=16035269.869201,
+    Q_0=11859436.505981,
+    Sn=120000000,
+    Vn=400000,
+    ra=0.001,
+    w(fixed=true),
+    x1d=0.302) annotation (Placement(transformation(extent={{-40,-10},{-20,10}})));
+  OpenHPL.Controllers.Governor governor(Pn=103,           Y_gv_ref = 0.1)
+                                       annotation (Placement(transformation(origin={0,-40},  extent = {{-10, -10}, {10, 10}})));
+  //(a = 7.862E-25, c = 1.108E-08, d = -5.344E-02, b = -1.010E-16)
+  Modelica.Blocks.Math.Gain fpu_to_fSI(k=SysData.fn) annotation (Placement(transformation(
+        origin={-60,-52},
+        extent={{6,6},{-6,-6}},
+        rotation=180)));
+  Modelica.Blocks.Sources.Ramp power(duration = 1, height = +1e6, offset = 12e6,
+    startTime=200) annotation (
+    Placement(transformation(origin={-36,-36}, extent={{-8,-8},{8,8}})));
+equation
+  connect(fpu_to_fSI.y, governor.f) annotation (
+    Line(points={{-53.4,-52},{-22,-52},{-22,-44},{-12,-44}},
+                                                           color = {0, 0, 127}));
+  connect(governor.Y_gv, turbine.u_t) annotation (
+    Line(points={{11,-40},{24,-40},{24,-68}}, color = {0, 0, 127}));
+  connect(governor.P_ref, power.y) annotation (
+    Line(points={{-12,-36},{-27.2,-36}},                   color = {0, 0, 127}));
+  connect(generator.vf, generator.vf0) annotation (Line(points={{-42,5},{-46,5},{-46,14},{-38,14},{-38,11}}, color={0,0,127}));
+  connect(generator.p, bus1.p) annotation (Line(points={{-20,0},{0,0}}, color={0,0,255}));
+  connect(discharge.o, tail.o) annotation (Line(points={{68,-80},{74,-80}}, color={28,108,200}));
+  connect(turbine.o, discharge.i) annotation (Line(points={{42,-80},{48,-80}}, color={28,108,200}));
+  connect(turbine.i, penstock.o) annotation (Line(points={{22,-80},{10,-80}}, color={28,108,200}));
+  connect(penstock.i, surgeTank.o) annotation (Line(points={{-10,-80},{-20,-80}},color={28,108,200}));
+  connect(surgeTank.i, intake.o) annotation (Line(points={{-40,-80},{-46,-80}}, color={28,108,200}));
+  connect(intake.i, reservoir.o) annotation (Line(points={{-66,-80},{-70,-80}}, color={28,108,200}));
+  connect(turbine.P_out, generator.pm) annotation (Line(points={{36,-69},{36,-22},{-52,-22},{-52,-5},{-42,-5}}, color={0,0,127}));
+  connect(generator.w, fpu_to_fSI.u) annotation (Line(points={{-19,9},{-14,9},{-14,20},{-72,20},{-72,-52},{-67.2,-52}}, color={0,0,127}));
+annotation (experiment(StopTime = 2000));
+end SimpleGen;