Fault Check

The fault_check object performs "support/islanding checks" on objects inside the powerflow module. Its primary purpose is to determine if a particular node or link is still in service after a reconfiguration or fault event. fault_check is set up to operate as an independent topology checking object, but does have ties to the reliability module and the restoration object's functionality. The fault_check object only works with the NR solver_method at this time. Other solvers may be incorporated at a later date.

For detailed information about reliability analysis and fault scenario setup, see the Reliability User Guide. A typical fault_check object would be implemented as

object fault_check {
    name fault_check_obj;
    check_mode ONCHANGE;
    output_filename outage_check.txt;
    }

As with other objects, not all of the parameters need to be specified. A minimal implementation would be similar to

object fault_check {
    name fault_check_obj;
    }

Fault Check Parameters

Properties

fault_check 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: fault_check table 1

Property Name	Type	Unit	I/O	Description
check_mode	enumeration	N/A	I	Defines the fault checking scheme utilized. Valid entries are - SINGLE - Fault checks and voltage support checks are only performed once, before the first solver pass of the NR solver. - ONCHANGE - Fault checks and voltage support checks are performed any time an admittance change is flagged on the NR solver. - ALL - Fault checks and voltage support checks are performed on every iteration - SINGLE_DEBUG - Fault checks and voltage support checks are only done once, at the very beginning of the simulation. This mode will terminate the simulation after doing the initial fault check. This mode also bypasses several "critical errors" that would ordinarily terminate the simulation immediately, to allow for debugging the topology better (e.g., an islanded single node). - SWITCHING - Special variant of ONCHANGE used with manipulation of switch objects and external interfaces. May be deprecated in the future.
output_filename	char1024	N/A	I	File name for the text file of support check status values. Will output the bus number, phase information, and island association (if relevant) at each timestamp the fault_check object runs. If full_output_file is set, this will include both supported and unsupported node lists.
reliability_mode	bool	N/A	I	Boolean flag to indicate if the fault_check object is running in a reliability-module-based mode. reliability will toggle this mode and it is only provided for user information, it is not a specifiable property.
strictly_radial	bool	N/A	IO	Boolean flag to indicate which topology checking algorithm to use. Defaults to true, indicating a radial system is represented. If set true, line from/to fields are explicitly utilized. If set to false, a algorithm supporting meshed topologies and arbitrary from/to designations is supported. Note: the meshed topology check is more exhaustive and slower, hence the option for when feeders are known to 100% be radial.
full_output_file	bool	N/A	I	Boolean flag to toggle what gets written to output_filename. Defaults to false, which will only output unsupported nodes in the output. If set to true, it will provide a list of unsupported and supported nodes. Useful with grid_association to see what island a node is associated.
grid_association	bool	N/A	I	Boolean flag to indicate if the island association checking is performed. This option must be enabled in multiple islands or multiple independent SWING node scenarios. If false, only the "primary SWING" node will be checked for topology continuity -- all other SWING-type nodes will be ignored and removed from service (if not connected to the primary SWING topology). When enabled, overrides strictly_radial to false.
eventgen_object	object	N/A	I	Object link to an eventgen object in the reliability module. This object will be used to implement any "unscheduled" faults, such as switch openings or fuses blowing. Without this object specified, such objects will still open or trip, but may result in an unsolvable system matrix and prematurely terminate the simulation.

Fault Check State of Development

The fault_check object has been rigorously tested for topology checking and islanding operations and is considered well-developed and validated on that functionality. The original implementation was developed in conjunction with the reliability module and the restoration object. That functionality has been tested and is considered validated, but rigorous testing has not been conducted and additional features may be added at a future date.