Tx line in DP formulation

andes/core/symprocessor.py

@@ -118,19 +118,26 @@ def generate_symbols(self):
                 self.tex_names[name] = sp.Symbol(tex_name)
         # -----------------------------------------------------------
 
+        # `all_params_names` include parameters, services, exports from blocks, etc.
         for var in self.cache.all_params_names:
+            is_real = True
+
+            if var in self.parent.services:
+                if self.parent.services[var].vtype == complex:
+                    is_real = False
+
             self.inputs_dict[var] = sp.Symbol(var)
 
         for var in self.cache.all_vars_names:
-            tmp = sp.Symbol(var)
+            tmp = sp.Symbol(var, real=True)  # all DAE variables are real
             self.vars_dict[var] = tmp
             self.inputs_dict[var] = tmp
             if var in self.cache.vars_int:
                 self.vars_int_dict[var] = tmp
 
         # store tex names defined in `self.config`
         for key in self.config.as_dict():
-            tmp = sp.Symbol(key)
+            tmp = sp.Symbol(key, real=True)  # not expecting complex numbers in config
             self.inputs_dict[key] = tmp
             if key in self.config.tex_names:
                 self.tex_names[tmp] = sp.Symbol(self.config.tex_names[key])
@@ -411,6 +418,8 @@ def generate_jacobians(self, diag_eps=1e-8):
             self.calls.append_ijv(f'{var.e_code}{var.v_code}c', e_idx, v_idx, eps)
             self.calls.need_diag_eps.append(var.name)
 
+        self.calls.need_diag_eps = sorted(list(set(self.calls.need_diag_eps)))
+
     def generate_pretty_print(self):
         """
         Generate pretty print variables and equations.

andes/models/__init__.py

@@ -18,7 +18,7 @@
     ('static', ['PQ', 'PV', 'Slack']),
     ('shunt', ['Shunt', "ShuntTD", 'ShuntSw']),
     ('interface', ['Fortescue']),
-    ('line', ['Line', 'Jumper']),
+    ('line', ['Line', 'Jumper', 'DPLine']),
     ('area', ['Area', 'ACE', 'ACEc']),
     ('dynload', ['ZIP', 'FLoad']),
     ('synchronous', ['GENCLS', 'GENROU', 'PLBVFU1']),

andes/models/line/__init__.py

@@ -4,3 +4,4 @@
 
 from andes.models.line.line import Line  # noqa
 from andes.models.line.jumper import Jumper  # noqa
+from andes.models.line.dpline import DPLine  # noqa

andes/models/line/dpline.py

@@ -0,0 +1,145 @@
+"""
+AC transmission line in dynamic phasor (shift frequency) formulation.
+"""
+
+
+from andes.core import (ModelData, IdxParam,
+                        Model, ExtAlgeb, ConstService, ExtParam, State)
+
+
+class DPLineData(ModelData):
+    """
+    Data for Line.
+    """
+
+    def __init__(self):
+        super().__init__()
+
+        self.line = IdxParam(info='Line index', model='Line')
+
+
+class DPLine(DPLineData, Model):
+    """
+    WIP
+
+    AC transmission line model in dynamic phasor (shift frequency) formulation.
+
+    The connectivity `u` logic is as follows:
+    - `u = 0` means the line is not replaced by DPLine. The line remains in the
+      phasor model, and the `u` of the phasor Line device applies.
+    - `u = 1` means the line is replaced by DPLine. Still, the connectivity
+      status of the DP line depends on the `u` of the phasor Line device.
+
+    """
+
+    def __init__(self, system=None, config=None):
+        DPLineData.__init__(self)
+        Model.__init__(self, system, config)
+        self.group = 'ACLine'
+        self.flags.pflow = False
+        self.flags.tds = True
+        self.flags.tds_init = True
+
+        self.bus1 = ExtParam(model='Line', src='bus1', indexer=self.line, export=False)
+        self.bus2 = ExtParam(model='Line', src='bus2', indexer=self.line, export=False)
+
+        self.a1 = ExtAlgeb(model='Bus', src='a', indexer=self.bus1, tex_name='a_1',
+                           info='phase angle of the from bus',
+                           ename='Pij',
+                           tex_ename='P_{ij}',
+                           )
+        self.a2 = ExtAlgeb(model='Bus', src='a', indexer=self.bus2, tex_name='a_2',
+                           info='phase angle of the to bus',
+                           ename='Pji',
+                           tex_ename='P_{ji}',
+                           )
+        self.v1 = ExtAlgeb(model='Bus', src='v', indexer=self.bus1, tex_name='v_1',
+                           info='voltage magnitude of the from bus',
+                           ename='Qij',
+                           tex_ename='Q_{ij}',
+                           )
+        self.v2 = ExtAlgeb(model='Bus', src='v', indexer=self.bus2, tex_name='v_2',
+                           info='voltage magnitude of the to bus',
+                           ename='Qji',
+                           tex_ename='Q_{ji}',
+                           )
+
+        self.ul = ExtParam(model='Line', src='u', indexer=self.line, tex_name='u', export=False)
+        self.g1 = ExtParam(model='Line', src='g1', indexer=self.line, tex_name='g_1', export=False)
+        self.g2 = ExtParam(model='Line', src='g2', indexer=self.line, tex_name='g_2', export=False)
+        self.b1 = ExtParam(model='Line', src='b1', indexer=self.line, tex_name='b_1', export=False)
+        self.b2 = ExtParam(model='Line', src='b2', indexer=self.line, tex_name='b_2', export=False)
+        self.r = ExtParam(model='Line', src='r', indexer=self.line, tex_name='r', export=False)
+        self.x = ExtParam(model='Line', src='x', indexer=self.line, tex_name='x', export=False)
+        self.g = ExtParam(model='Line', src='g', indexer=self.line, tex_name='g', export=False)
+        self.b = ExtParam(model='Line', src='b', indexer=self.line, tex_name='b', export=False)
+        self.tap = ExtParam(model='Line', src='tap', indexer=self.line, tex_name='tap', export=False)
+
+        self.gh = ConstService(tex_name='g_h')
+        self.bh = ConstService(tex_name='b_h')
+        self.gk = ConstService(tex_name='g_k')
+        self.bk = ConstService(tex_name='b_k')
+
+        self.yh = ConstService(tex_name='y_h', vtype=complex)
+        self.yk = ConstService(tex_name='y_k', vtype=complex)
+        self.yhk = ConstService(tex_name='y_{hk}', vtype=complex)
+
+        self.ghk = ConstService(tex_name='g_{hk}')
+        self.bhk = ConstService(tex_name='b_{hk}')
+
+        self.itap = ConstService(tex_name='1/t_{ap}')
+        self.itap2 = ConstService(tex_name='1/t_{ap}^2')
+
+        self.Leq = ConstService(v_str='x/(2*pi*60)')
+
+        self.ue = ConstService(v_str='ul * u')
+
+        self.gh.v_str = 'g1 + 0.5 * g'
+        self.bh.v_str = 'b1 + 0.5 * b'
+        self.gk.v_str = 'g2 + 0.5 * g'
+        self.bk.v_str = 'b2 + 0.5 * b'
+
+        self.yh.v_str = 'u * (gh + 1j * bh)'
+        self.yk.v_str = 'u * (gk + 1j * bk)'
+        self.yhk.v_str = 'u/((r+1e-8) + 1j*(x+1e-8))'
+
+        self.ghk.v_str = 're(yhk)'
+        self.bhk.v_str = 'im(yhk)'
+
+        self.itap.v_str = '1/tap'
+        self.itap2.v_str = '1/tap/tap'
+
+        self.r2x2 = ConstService(v_str='r*r + x*x')
+
+        # in implicit form but has the same dq-axis alignment as in ANDES implementation)
+        self.idd = State(info='real current',
+                         tex_name='idd',
+                         v_str='ue * (r*v1*sin(a1)/r2x2 - r*v2*sin(a2)/r2x2 - v1*x*cos(a1)/r2x2 +'
+                               '      v2*x*cos(a2)/r2x2)',
+                         e_str='ue * (-x*iqq - r*idd - v2*sin(a2) + v1*sin(a1)) + (1-ue) * idd',
+                         t_const=self.Leq,
+                         )
+
+        self.iqq = State(info='real current',
+                         tex_name='iqq',
+                         v_str='ue * (r*v1*cos(a1)/r2x2 - r*v2*cos(a2)/r2x2 + v1*x*sin(a1)/r2x2 -'
+                               '      v2*x*sin(a2)/r2x2)',
+                         e_str='ue * (x*idd - r*iqq - v2*cos(a2) + v1*cos(a1)) + (1-ue) * iqq',
+                         t_const=self.Leq,
+                         )
+
+        self.a1.e_str = 'ue * (idd*v1*sin(a1) + iqq*v1*cos(a1))'
+
+        self.v1.e_str = 'ue * (-idd*v1*cos(a1) + iqq*v1*sin(a1))'
+
+        self.a2.e_str = 'ue * (-idd*v2*sin(a2) - iqq*v2*cos(a2))'
+
+        self.v2.e_str = 'ue * (idd*v2*cos(a2) - iqq*v2*sin(a2))'
+
+    def v_numeric(self, **kwargs):
+        """
+        Disable phasor lines that have been replaced by DP lines.
+        """
+
+        mask_idx = [self.line.v[i] for i in range(self.n) if self.u.v[i] == 1]
+        self.system.groups['ACLine'].set(src='u', idx=mask_idx, attr='v', value=0)

andes/routines/tds.py

@@ -813,7 +813,7 @@ def do_switch(self):
 
         # check system connectivity after a switching
         if ret is True and self.config.check_conn == 1:
-            system.connectivity(info=False)
+            system.connectivity(info=False, routine='tds')
 
         return ret
 

andes/system.py

@@ -1196,7 +1196,7 @@ def vars_to_models(self):
             if var.n > 0:
                 var.v[:] = self.dae.x[var.a]
 
-    def connectivity(self, info=True):
+    def connectivity(self, info=True, routine='pflow'):
         """
         Perform connectivity check for system.
 
@@ -1225,6 +1225,11 @@ def connectivity(self, info=True):
         to.extend(self.Line.a2.a.tolist())
         u.extend(self.Line.u.v.tolist())
 
+        if routine == 'tds':
+            fr.extend(self.DPLine.a1.a.tolist())
+            to.extend(self.DPLine.a2.a.tolist())
+            u.extend(self.DPLine.u.v.tolist())
+
         # collect from Jumper
         fr.extend(self.Jumper.a1.a.tolist())
         to.extend(self.Jumper.a2.a.tolist())

docs/source/release-notes.rst

@@ -9,6 +9,12 @@ The APIs before v3.0.0 are in beta and may change without prior notice.
 v1.9 Notes
 ==========
 
+v1.9.3 (2024-04-XX)
+-------------------
+- In symbolic processor, most variables are assumed to be real, except some
+  services that are specified as complex. This will allow generating simplified
+  expressions.
+
 v1.9.2 (2024-03-25)
 -------------------
 - Improve PSS/E parser for the `wmod` field in the static generator