<< Click to Display Table of Contents >> Navigation:  Calculations > Protection > Protection for Enexis > Analyse

If necessary, select a number of objects.

Start the calculation with: Calculate | Security | Enexis | Analysis.

In the calculation settings form, the scaling percentages for load and generation can be specified. Also whether the analysis should be performed on the selected objects or on all objects. Fault types and having circuit breakers rejected can also be set here.

 

The analysis simulates many blunt short circuits, at (selected) nodes and in (selected) cables, with different fault types.

For cables, the short-circuits are basically made every 100 metres. For short cables, however, five locations are tested. For long cables, 40 locations are used.

 

During the tripping sequence, consideration is given to:

•Which protections switch off at what time

•Thermal load of branches and switches (I²t)

•Current in branches and switches afterwards

 

The analysis calculates per short circuit:

•Short circuit not tripped

•Short circuit not selectively tripped

•Power switches tripped

•Contact factors of the protections (I / I> )

•Overloaded branches

•Overloaded switches

•Unavailable transport nodes and number of unavailable distribution nodes

 

 

RESULTS

 

Network

After performing the analysis, results are displayed as text in the diagram.

 

For nodes and cables, the results are:

•Number of times (or length) not disconnected

•Number of times (or length) not selective

•Number of times overloaded by a short circuit (somewhere else)

 

Colour indication

Nodes and branches are displayed in colour when problems occur.

Colour selection takes place in the Options, under Calculation | General.

 

 

 

 

General

Calculate | Results | Overview provides an overview of nodes and cables that have a protection problem. This is:

•not switched off

•not selective

•causes overloading

 

Details

With Calculate | Results | Details (or right-clicking on an object in result mode), information of selected nodes and cables is displayed in a form.

The "Details" button displays the protection items in a table.

One line per short circuit.

The results per short circuit are:

•The fault distance (only for cable)

•The fault type

•Possibly which circuit breaker refuses

•Whether the short circuit is not tripped

•Whether the disconnection is not selective

•The switches that actually disconnect

•The response factors of the circuit breakers that actually trip

•The thermally and/or current-overloaded branches

•The thermally and/or current-overloaded switches

•The unavailable transport nodes

•The number of unavailable distribution nodes

Right-click anywhere to turn on the filter via the popup menu and then set the filter.

 

Export

The results can be exported to Excel using Calculate | Results | Export. The export is a report of all short circuits in objects, in a fixed format, on two worksheets: Nodes and Cables.