Node
[Powerflow objects (abstract)]

---

Detailed Description

The node is one of the major components of the method used for solving a powerflow network.

Id

node.h 1201 2009-01-08 22:31:37Z d3x593

Copyright (C) 2008 Battelle Memorial Institute

In essense the distribution network can be seen as a series of nodes and links. Nodes primary responsibility is to act as an aggregation point for the links that are attached to it, and to hold the current and voltage values that will be used in the matrix calculations done in the link.

Three types of nodes are defined in this file. Nodes are simply a basic object that exports the voltages for each phase. Triplex nodes export voltages for 3 lines; line1_voltage, line2_voltage, lineN_voltage.

Voltage control

When the global variable require_voltage_control is set to TRUE, the bus type is used to determine how voltage control is implemented. Voltage control is only performed when the bus has no link that considers it a to node. When the flag #NF_HASSOURCE is cleared, then the following is in effect:

• #SWING buses are considered infinite sources and the voltage will remain fixed regardless of conditions.
• #PV buses are considered constrained sources and the voltage will fall to zero if there is insufficient voltage support at the bus. A generator object is required to provide the voltage support explicitly. The voltage will be set to zero if the generator does not provide sufficient support.
• #PQ buses will always go to zero voltage.

Fault support

The following conditions are used to describe a fault impedance X (e.g., 1e-6), between phase x and neutral or group, or between phases x and y, and leaving phase z unaffected at iteration t:

• phase-to-phase contact at the node
  • Forward-sweep:
  • Back-sweep: ;
• phase-to-ground/neutral contact at the node
  • Forward-sweep:
  • Back-sweep: ;

Modules
	Triplex_node
Functions
LINKCONNECTED *	node::attachlink (OBJECT *obj)
	Attachlink is called by link objects during their creation.
EXPORT int	create_node (OBJECT **obj, OBJECT *parent)
	REQUIRED: allocate and initialize an object.
EXPORT int	init_node (OBJECT *obj)
	Object initialization is called once after all object have been created.
int	node::kmldump (FILE *fp)
int *	node::NR_populate (void)
	NR_populate is called by link objects during their first presync if a node is not "initialized".
EXPORT TIMESTAMP	sync_node (OBJECT *obj, TIMESTAMP t0, PASSCONFIG pass)
	Sync is called when the clock needs to advance on the bottom-up pass (PC_BOTTOMUP).
Variables
static unsigned int	node::n = 0
	node count */

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Function Documentation

LINKCONNECTED * node::attachlink

(

OBJECT *

obj

)

[inherited]

Attachlink is called by link objects during their creation.

It creates a linked list of links that are attached to the current node.

Parameters:

obj

the link that has an attachment to this node

Parameters:

obj	object to attach

Definition at line 2412 of file node.cpp.

References link::from, gl_error, gl_malloc, OBJECTDATA, and link::to.

EXPORT int create_node	(	OBJECT **	obj,
		OBJECT *	parent
	)

REQUIRED: allocate and initialize an object.

Parameters:

	obj	a pointer to a pointer of the last object in the list
	parent	a pointer to the parent of this object

Returns:

1 for a successfully created object, 0 for error

Definition at line 2127 of file node.cpp.

References gl_create_object, gl_error, gl_set_parent, and OBJECTDATA.

EXPORT int init_node

(

OBJECT *

obj

)

Object initialization is called once after all object have been created.

Parameters:

obj

a pointer to this object

Returns:

1 on success, 0 on error

Definition at line 2189 of file node.cpp.

References GL_THROW, and OBJECTDATA.

int node::kmldump

(

FILE *

fp

)

[inherited]

Todo:

complete KML implement of supply (ticket #133)

Definition at line 2038 of file node.cpp.

References gl_object_isa, OBJECTDATA, OBJECTHDR, PHASE_A, PHASE_B, and PHASE_C.

int * node::NR_populate

(

void

)

[inherited]

NR_populate is called by link objects during their first presync if a node is not "initialized".

This function "initializes" the node into the Newton-Raphson data structure NR_busdata

Definition at line 2447 of file node.cpp.

References gl_malloc, GL_THROW, OBJECTHDR, PHASE_A, PHASE_B, and PHASE_C.

EXPORT TIMESTAMP sync_node	(	OBJECT *	obj,
		TIMESTAMP	t0,
		PASSCONFIG	pass
	)

Sync is called when the clock needs to advance on the bottom-up pass (PC_BOTTOMUP).

Parameters:

	obj	the object we are sync'ing
	t0	this objects current timestamp
	pass	the current pass for this sync call

Returns:

t1, where t1>t0 on success, t1=t0 for retry, t1<t0 on failure

Definition at line 2210 of file node.cpp.

References gl_error, OBJECTDATA, PC_BOTTOMUP, PC_POSTTOPDOWN, and PC_PRETOPDOWN.