Triplex Line

The third type of line available in the powerflow module is the triplex lines. Triplex lines represent the distribution wires coming from the transformer into a typical residential home. That is, they are typically composed of one neutral wire and two "hot" wires. Triplex lines require the phase S to be specified as part of the phases parameter for proper implementation. A typical triplex line would be implemented in a similar fashion to

object triplex_line {
    phases AS;
    length 100 ft;  
    from node_4a;
    to node_4;
    configuration triplex_config_AB;
    }

As with the underground_line and overhead_line objects, triplex_line objects inherit all of their properties from the line object. However, triplex_lines use a different configuration structure than the overhead_line and underground_line objects.

Triplex Line State of Development

Triplex Line is considered a highly developed and validated model in terms of powerflow solutions, however, models may be developed to include more advanced features in the future.

Triplex Line Configuration

Triplex lines utilize their own configuration description method. Since the phases are no longer described as A, B, or C, the configuration is relabeled. A typical triplex_line_configuration is given as either a geometric configuration

object triplex_line_configuration {
        conductor_1 trip_cond_H;
        conductor_2 trip_cond_H;
        conductor_N trip_cond_N;
        insulation_thickness 0.08 in;
        diameter 0.368 in;
        }

or by using an explicit z-matrix

object triplex_line_configuration {
               z11 1.52+0.61j;
               z12 +0.55+0.44j;
               z21 -0.55-0.44j;
               z22 -1.52-0.61j;
               }

Note: The explicit z-matrix version is an under-determined system. Ground and neutral currents will not be calculated, however, voltage and line currents will be correctly calculated.

Triplex Line Configuration Parameters

Properties

triplex_line_configuration does not declare inherited parent classes.

The I/O column indicates whether a property is user-settable input (I), simulation-computed output (O), or both (IO).

Table 1: triplex_line table 1

Property Name	Type	Unit	I/O	Description
conductor_1	object	N/A	I	triplex_conductor object that represents the physical wire of phase 1.
conductor_2	object	N/A	I	triplex_conductor object that represents the physical wire of phase 2.
conductor_N	object	N/A	I	triplex_conductor object that represents the physical wire of the neutral phase.
insulation_thickness	double	in	I	Thickness of the insulation around the phase 1 and phase 2 conductors
diameter	double	in	I	Diameter of the conductor
spacing	object	N/A	I	line_spacing object with information on the physical layout of the conductors. This parameter is unused at this point. Future versions of GridLAB-D™ may implement this functionality
z11	complex	Ohm/mile	I	Phase 1 self-impedance, used for direct entry of impedance values
z12	complex	Ohm/mile	I	Phase 1-2 induced impedance, used for direct entry of impedance values
z21	complex	Ohm/mile	I	Phase 2-1 induced impedance, used for direct entry of impedance values
z22	complex	Ohm/mile	I	Phase 2 self-impedance, used for direct entry of impedance values
rating.summer.continuous	double	A	I	Amp rating in summer, continuous
rating.summer.emergency	double	A	I	Amp rating in summer, short term
rating.winter.continuous	double	A	I	Amp rating in winter, continuous
rating.winter.emergency	double	A	I	Amp rating in winter, short term

Triplex Line Configuration State of Development

Triplex Line Configuration is considered a highly developed and validated model.

Triplex Line Conductor

As with the underground_line and overhead_line objects, triplex_line objects have their own conductor objects. This object describes the physical characteristics of the actual wire used in the triple line bundle. A typical implementation would be:

object triplex_line_conductor {
    name trip_cond_1;
    resistance 0.97;
    geometric_mean_radius 0.0111;       
    }

Triplex Line Conductor Parameters

Properties

triplex_line_conductor does not declare inherited parent classes.

The I/O column indicates whether a property is user-settable input (I), simulation-computed output (O), or both (IO).

Table 2: triplex_line table 2

Property Name	Type	Unit	I/O	Description
resistance	double	Ohm/mile	I	Resistance of the conductor.
geometric_mean_radius	double	ft	I	GMR of conductor.
rating.summer.continuous	double	A	I	Amp ratings for the cable during continuous operation in summer
rating.summer.emergency	double	A	I	Amp ratings for the cable during short term operation in summer
rating.winter.continuous	double	A	I	Amp ratings for the cable during continuous operation in winter
rating.winter.emergency	double	A	I	Amp ratings for the cable during short term operation in winter

Triplex Conductor State of Development

Triplex Conductor is considered a highly developed and validated model.