Export System Design Methodology
================================

For details of the code implementation, please see
:doc:`Export System Design API <api_ExportSystemDesign>`.

Overview
--------

Below is an overview of the process used to design an export cable system in
ORBIT. For more detail on the helper classes used to support this design please
see :doc:`Cabling Helper Classes <doc_CableHelpers>`, specifically
:class:`Cable` and :class:`CableSystem`.

Number of Required Cables
-------------------------

The number of export cables required is calculated by dividing the windfarm's
capacity by the configured export cable's power rating and adding any user
defined redundnacy as seen below.

:math:`num\_cables = \lceil\frac{plant\_capacity}{cable\_power}\rceil + num\_redundant`

Export Cable length
-------------------

The total length of the export cables is calculated as the sum of the site
depth, distance to landfall and distance to interconnection multiplied by the
user defined :py:attr`percent_added_length` to account for any exclusions or
geotechnical design considerations that make a straight line cable route
impractical.

:math:`length = (d + distance_\text{landfall} + distance_\text{interconnection} * (1 + length_\text{percent_added})`

Design Result
-------------

The result of this design module (:py:attr:`design_result`) is a list of cable
sections and their lengths and masses that represent the export cable system.
This result can then be passed to the
:doc:`export cable installation module <../install/export/doc_ExportCableInstall>`
to simulate the installation of the system.

Process Diagrams
----------------

.. image:: ../../images/process_diagrams/ExportSystemDesign.png