Design codes#

A design-code plugin turns your parameter file into weather cases (.ohlwc) and load cases (.ohllc) for a line: the cases the code asks for, the wind pressures and ice loads computed the way the code computes them, the partial and combination factors put on the vertical, transverse and longitudinal loads, and the strength factor. The plugin also returns notes: what it computed, assumed or left out, and may give clearance presets for the Vertical and Radial clearances windows (below).

OpenOHL ships no code tables. Standards are copyrighted, and their values change with editions and national annexes. Each plugin implements a code's method; every number — basic wind speeds, ice thicknesses, temperatures, γ and ψ factors, safety factors, district or zone values — is read from your parameter file, which you fill in from the standard you hold. Each plugin's example-parameters.toml (also the template it gives) uses invented placeholder values, clearly marked: replace them all before using the cases.

The plugins#

They live in plugins/codes/, one per code, each with a README listing its parameter file keys:

Build them once (they are WebAssembly components):

rustup target add wasm32-wasip2
for d in plugins/codes/*/; do [ -f "$d/ohl-plugin.toml" ] && (cd "$d" && cargo build --release --target wasm32-wasip2); done

EN 50341 and national annexes#

The EN 50341 parameter file has the general values (wind, ice, combined wind and ice, temperatures, partial factors) and an [nna] section: any table of the general part given again under nna (e.g. [nna.wind]) replaces the general values key by key, and [[nna.extra_weather]] / [[nna.extra_load_case]] add the national cases. The notes list the keys the annex replaced.

The wind pressure on conductors is \( q = c_e(h)\cdot\tfrac{1}{2}\rho\,(f\,v_b)^2\cdot G_c\cdot C_c \), with \( f \) = 1 for the extreme wind and the file's fraction for the other cases. Combined wind and ice is generated twice: ice dominant (\( \gamma_I \) on the ice, \( \gamma_W\psi_W \) on the wind) and wind dominant (\( \gamma_I\psi_I \), \( \gamma_W \)). The strength factor is \( 1/\gamma_M \).

A plugin for the Swiss Leitungsverordnung (LeV / OLEI, SR 734.31) exists separately; it is not part of the public code.

Clearance presets#

A design-code plugin may also return clearance presets: for the Vertical clearances or the Radial clearances window, a rule file (.ohlr: the rules — LiDAR classes, voltages, distances, the vertical zone's half width per rule —, the wind steps and sides, the circuits, the calculation method and the distance beyond which LiDAR points are ignored) and the weather cases its rules name (.ohlwc). OpenOHL checks them like any such file (each rule's weather cases among the preset's), and writes each as <plugin>-<name>.ohlr among the project's rule files and <plugin>-<name>.ohlwc among its weather case files (next to a line file; ohl code generate: next to the weather case file). In a window, Load preset… takes one in a click: its rules replace the window's, its weather cases missing from the model are added to it; you can change everything afterwards (see Vertical and radial clearances). The plugins in plugins/codes give none.

From the command line#

ohl code list                               # plugins/codes, or --dir DIR
ohl code template --plugin plugins/codes/en50341 --out my-line.toml
# … fill in my-line.toml from the standard …
ohl code generate --plugin plugins/codes/en50341 --params my-line.toml \
    --weather my-line.ohlwc --load-cases my-line.ohllc
ohl line line.ohl.json --weather my-line.ohlwc --load-cases my-line.ohllc --loads-csv loads.csv

generate checks both files as OpenOHL reads them (and that each load case names one of the weather cases) before writing them, writes the clearance presets next to the weather case file, and prints the notes.

In the desktop application#

Install a code plugin or add its folder in Plugins › Plugin manager (e.g. plugins/codes). Then Criteria › Design code…:

1. choose the code;
2. Save the plugin's template… to start a parameter file, fill it in;
3. choose the Parameter file…;
4. Generate.

The two files (named as given, default the plugin's name) go into the project's libraries — kept in the project file like any library file — or next to a line file; a file of that name is replaced. The model then uses them: the weather cases are solved, and Structure loads uses the load cases. The code's clearance presets go into the project's rule and weather case files (for the clearance windows' Load preset…). The code's notes are shown in the window.

What is not generated yet#

Every plugin says in its notes what it leaves out. In this first version: security and failure-containment loads (broken wire, unbalanced ice) — use the broken-span solve and your own load cases; construction and maintenance loads; wind on structures by the code's own method (the structure loads apply each weather case's wind pressure to the structure types' height bands, see Load cases); the NESC constant k (the notes give its value to add by hand); per-wire ice loads that depend on the conductor diameter (one reference diameter per parameter file).