Tabular converter
Tabular data can come from Excel files, a set of CSV files, GNF files, databases, pandas DataFrames, etc etc.
The similarity between all tabular data is that it contains multiple tables
,
each with multiple columns
, possibly with a specific unit
.
Others may have a categorical value which needs to be mapped (i.e. open: 0, closed: 1); in general we’ll call these
substitutions
.
Mapping file
A mapping file is a yaml with three main sections grid
, units
and substitutions
:
grid:
Nodes:
node:
auto_id:
key: Number
u_rated: Unom
extra: ID
Cables:
line:
id:
auto_id:
key: Number
from_node:
auto_id:
table: Nodes
key:
Number: From.Number
from_status: From.Switch state
to_node:
auto_id:
table: Nodes
key:
Number: To.Number
to_status: To.Switch state
units:
A:
F:
µF: 0.000001
substitutions:
".*Switch state":
"off": 0
"on": 1
Grid
For each table
, the target PGM component
is listed (e.g. Nodes: node, Cables: line).
The for each PGM column
the source column is supplied (e.g. u_rated: Unom, from_status: From.SwitchStatus).
Field Definitions
If the column
definition is a one on one mapping,
the value is simply the name of the source column (e.g.u_rated: Unom),
but in many cases the mapping is a bit more complex.
You can use the following column
definitions:
Column name
str
from_node: From.Number
First matching column name
str
p_specified: Inverter.Pnom | Inverter.Snom
Reference to a column on another sheet (using
!
notation as in Excel)str
r1: CableProperties!R[Shortname=Type short]
You may also specify the reference more explicitly:
r1: CableProperties!R[CableProperties!Shortname=Cables!Type short]
Constant value
int | float
from_status: 1 tan1: 0.0
Functions
Dict[str, List[Any]
p_specified: min: - Pnom - Inverter.Pnom
Nested definitions:
q_specified: power_grid_model_io.filters.phase_to_phase.reactive_power: - min: - Pnom - Inverter.Pnom | Inverter.Snom - Inverter.cos phi - 1.0
Is similar to:
from power_grid_model_io.filters.phase_to_phase import reactive_power q_specified = reactive_power( min( table["Pnom"], table["Inverter.Pnom"] if "Inverter.Pnom" in table else table["Inverter.Snom"] ), table["Inverter.Snom"], 1.0 )
Units
Power Grid Model uses SI units (e.g. “W” for Watts),
but source data may be supplied in different units (e.g. “MW” for Mega Watts).
If units are supplied in the tabular data,
the pandas DataFrame storing the data is expected to have MultiIndexes
for the columns.
For our application, a MultiIndex
can be interpreted as a tuple; the first element is the column name, the second
element is the column unit. For example: ("C0", "µF")
.
If a unit is supplied, it should be defined in the units section of the mapping. Undefined units are not allowed to prevent errors.
units:
A:
F:
µF: 0.000001
ohm/m:
ohm/km: 0.001
The definitions above can be interpreted as:
A is a valid SI unit
F is a valid SI unit
1 µF = 0.000001 A
ohm/m is a valid SI unit
1 ohm/km = 0.001 ohm/m
Substitutions
Some columns may contain categorical values (enums) which should be replaced. The column names can be defined as regular expressions.
substitutions:
".*Switch state":
"off": 0
"in": 1
N1:
none: false
own: true
The definitions above can be interpreted as:
In all columns that end with
SwitchState
(e.g.From.Switch State
,To.Switch State
or justSwitch State
), the word “off” should be replaced with the integer 0 and the word “in” should be replaced with the value 1.In all columns called “N1”, the word “none” should be replaced with the boolean
false
and the word “own” should be replaced with the value booleantrue
.
AutoID
The id
field is special in the sense that each object should have a unique numerical id in power grid model.
Therefore, each id definition is mapped to a numerical ID.
Also each field name that ends with node
is converted into the matching numerical ID.
from power_grid_model_io.utils.auto_id import AutoID
auto_id = AutoID()
a = auto_id("Alpha") # a = 0
b = auto_id("Bravo") # b = 1
c = auto_id("Alpha") # c = 0 (because key "Alpha" already existed)
item = auto_id[1] # item = "Bravo"
See also power_grid_model_io.utils.AutoID