Snapshots and time series

[jiedxu]

To Do

• [x] OpenDSS allows users to specify time series when defining elements. See EU-LV example, http://svn.code.sf.net/p/electricdss/code/trunk/Distrib/IEEETestCases/LVTestCase/
• [x] Time series is specified when adding elements in PyPSA, https://pypsa.readthedocs.io/en/latest/design.html#time-varying-data
• [x] Time series must be set as controller in pandapower, https://pandapower.readthedocs.io/en/v2.5.0/timeseries.html
• [ ] Dataframe with columns being element type, name, attribute
• [x] What if two conversion elements in different types have the same name? It's assumed every conversion element has a unique name.
• [ ] Conversion element can return tuples for variable attributes.
• [x] Reference to previous cooked snapshot

[jiedxu]

Incremental Data Structure

• https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.DataFrame.cumsum.html
• previous attribute points to the previous snapshot.
• There is a default snapshot. It should be placed at the beginning of the series.
• Voltages and flows should not be stored in the incremental form.
• This structure is designed for voltage sensitivity analysis.

[jiedxu]

Start with Time Series

• Initiate a snapshot series.
• Add time series one-by-one.
• Add or delete snapshot.