Fuse

Fuse objects are used to place a current limitation between two nodes. If the current is exceeded, the fuse will open and prevent further current flow. Due to limitations in the Forward-Back Sweep algorithm, fuses only affect the first downstream node. If other loads exist downstream, they will cause an oscillatory voltage swing that has no real representation. reliability module functionality only exists in the Newton-Raphson solver at this time. A minimalist fuse could be implemented as

object fuse {
     phases "ABC";
     name node1-node2;
     from node1;
     to node2;
     }

A typical fuse object would be implemented, with the same parameters as above, as

object fuse {
    phases "ABC";
    name node1-node2;
    from node1;
    to node2;
    current_limit 9999.0 A;
    mean_replacement_time 3600.0;
    repair_dist_type NONE;
    }

Fuse Parameters

Properties

fuse objects are derived from link objects, so any parameters of the link object are available as well.

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

Table 1: fuse table 1

Property Name	Type	Unit	I/O	Description
phase_A_status	enumeration	N/A	IO	Status of the fuse on phase A (only valid if phase A is in the phases property). Two keywords are valid: - GOOD - The fuse on phase A is still conducting and has not exceeded its current limit. - BLOWN - The fuse on phase A has exceeded its current limit and is no longer conducting.
phase_B_status	enumeration	N/A	IO	Status of the fuse on phase B (only valid if phase B is in the phases property). Two keywords are valid: - GOOD - The fuse on phase B is still conducting and has not exceeded its current limit. - BLOWN - The fuse on phase B has exceeded its current limit and is no longer conducting.
phase_C_status	enumeration	N/A	IO	Status of the fuse on phase C (only valid if phase C is in the phases property). Two keywords are valid: - GOOD - The fuse on phase C is still conducting and has not exceeded its current limit. - BLOWN - The fuse on phase C has exceeded its current limit and is no longer conducting.
repair_dist_type	enumeration	N/A	I	Distribution to be used after a fuse has blow to restore it. Current valid settings are: - NONE - No distribution is used and the value in mean_replacement_time is taken directly. - EXPONENTIAL - An exponential distribution is used with mean_replacement_time taken as one over the lambda value.
current_limit	double	A	I	Current rating for the fuse. If exceeded, the particular phase will go to an open circuit condition.
mean_replacement_time	double	s	I	Mean time to replace the fuse if blown. This could represent a travel requirement (remote location) or scarcity requirement (shipping time for parts). This value overrides any value specified in mean_repair_time for the link object itself.
fuse_resistance	double	Ohm	I	The resistance value of the fuse when it is not blown.

Fuse State of Development

Fuse is considered a well developed and validated model in terms of powerflow solutions. Reliability functionality has been tested and validated, but is not fully vetted and may change as advanced functionality is included.