Pandapower

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- [ADDED] Create functions for multiple gens, sgens, lines, trafos and switches
- [ADDED] Unbalanced power flow runpp_3ph
- [ADDED] Zero sequence power flow models for ext_grid, transformer, line, asymmetric_load, asymmetric_sgen
- [ADDED] Minimal 1ph fault calculation according to IEC 60909
- [CHANGED] OPF calculate_voltage_angles defaults to True instead of False
- [ADDED] lightsim2grid interface in NR power flow thanks to BDonnot https://github.com/BDonnot/lightsim2grid
- [FIXED] PowerModels.jl solver interface call functions. Added OPFNotConverged to Powermodels.jl call
- [FIXED] pandas 1.0 and 1.1 support
- [CHANGED] revision of toolbox function drop_out_of_service_elements()
- [ADDED] toolbox function drop_measurements_at_elements()
- [ADDED] Encryption for JSON I/O
- [FIXED] Bug in converting measurements of out-of-service branch in state estimation 859
- [FIXED] Bug in using initialization option "results" in state estimation 859
- [CHANGED] In state estimation power flow results will not be renamed anymore
- [ADDED] New feature for defining the number of logging columns for an eval_function of an outputwriter log variable. Example: See log_variable docstring

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- [CHANGED] reset_results empties result tables per default
- [CHANGED] nan values result tables of power system test cases are emptied
- [ADDED] dclines and considering given branch indices by create_nxgraph()
- [ADDED] use_umfpack and permc_spec option from scipy spsolve in Newton-Raphson power flow
- [FIXED] Changed the __deepcopy__ for pandapowerNet back to using copy.deepcopy, fixed the issue that caused the switch to json 676
- [FIXED] Potential memory leaks due to circular references in JSONSerializableObjects, fixed by using weakref 677

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- [FIXED] Missing csv files 625
- [FIXED] deepcopy speed and missing DataFrames in net 620, 631
- [FIXED] simple plotly error with generic coords 619
- [FIXED] create line with passed geodata 610
- [FIXED] ConstControl write to and all_index attribute 609
- [FIXED] collection plotting issue 608

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- [ADDED] control and timeseries module
- [ADDED] Support phasor measurement in state estimation
- [ADDED] Support recycle in state estimation
- [ADDED] PowerModels.jl converter callable without running the PowerModels optimization
- [ADDED] Other PowerModels features via interface callable (e.g. network data check and different solver)
- [ADDED] toolbox function select_subnet now also copies cost data and net parameters
- [ADDED] toolbox functions replace_ward_by_internal_elements and replace_xward_by_internal_elements
- [ADDED] consideration of result tables in toolbox functions drop
- [ADDED] new jupyter notebook examples for time series, controller and PowerModels.jl interface
- [ADDED] reindex_buses() toolbox function

- [FIXED] Bugfixes in PowerModels conversion, OPF in general and tests
- [FIXED] renew opf_task() toolbox function which got outdated
- [FIXED] dtype at element parameter in cost tables
- [FIXED] convert_format.py: added the renaming of controller column and of the controller attributes, added tests for version 2.1.0

- [CHANGED] Unified the mesurement unit conversion of state estimation in ppc conversion
- [CHANGED] OPF bounds and settings for gens. limits or fixed values can now be enforced. See 511
- [CHANGED] OPF documentation and _check_necessary_opf_parameters()
- [CHANGED] JSON I/O: pandapower objects that are derived from JSONSerializableClass are now instantiated using __new__ instead of __init__ (as before), and the serialization has been adjusted; self.update_initialized(locals()) is not necessary anymore and has been removed; restore_json_objects is not needed anymore and has been removed
- [CHANGED] column name in net.controller: "controller" -> "object"
- [CHANGED] variable names in ContinuousTapControl ("u_set" -> "vm_set_pu") and in DiscreteTapControl ("u_lower" -> "vm_lower_pu", "u_upper" -> "vm_upper_pu")
- [CHANGED] __version__ is now changed to 2.2.0

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- [ADDED] calc_single_sc function to analyse a single fault instead of vectorized fault
- [ADDED] convenience function for logarithmic colormaps in plotting
- [CHANGED] corrected spelling 'continous' to 'continuous' in several functions
- [ADDED] additional standard types for overhead lines
- [CHANGED] make pp.to_json format closer to the JSON standard 406
- [ADDED] PowerModels.jl storage interface for time series based storage optimization.
- [ADDED] PowerModels.jl OTS interface for optimize transmission switching optimization.
- [ADDED] PowerModels.jl TNEP interface for transmission expansion optimization. See Jupyter Notebook
- [ADDED] pytest slow marker for tests and functions to run all, slow or fast tests
- [ADDED] Graph-Tool interface
- [ADDED] Multiple new algorithms and robust estimators in state estimation
- [ADDED] Support measurements for trafo3w in state estimation
- [ADDED] Auto zero-injection bus handling in state estimation

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- [FIXED] bug in short-circuit impedance of gens
- [ADDED] use estimation of rdss_pu defined in IEC 60909 of gens if not defined