--------------------
- [CHANGED] net.line.imax_ka to net.line.max_i_ka for consistency reasons
- [ADDED] net.line.tp_st_degree for phase shift in trafo tap changers
- [ADDED] sn_kva parameter in create_empty network for per unit system reference power
- [ADDED] parameter parallel for trafo element
- [ADDED] connectivity check for power flow to deal with disconnected network areas
- [ADDED] backward/forward sweep power flow algorithm specially suited for radial and weakly-meshed networks
- [ADDED] linear piece wise and polynomial OPF cost functions
- [ADDED] possibility to make loads controllable in OPF
- [ADDED] to_json and from_json functions to save/load networks with a JSON format
- [ADDED] generator lookup to allow multiple generators at one bus
- [CHANGED] Initialization of calculate_voltage_angles and init for high voltage networks
- [ADDED] bad data detection for state estimation
- [CHANGED] from_ppc: no detect_trafo anymore, several gen at each node possible
- [CHANGED] validate_from_ppc: improved validation behaviour by means of duplicated gen and branch rearangement
- [ADDED] networks: case33bw, case118, case300, case1354pegase, case2869pegase, case9241pegase, GBreducednetwork, GBnetwork, iceland, cigre_network_mv with_der='all' der
- [ADDED] possibility to add fault impedance for short-circuit current calculation
- [ADDED] branch results for short circuits
- [ADDED] static generator model for short circuits
- [ADDED] three winding transformer model for short circuits
- [FIXED] correctly neglecting shunts and tap changer position for short-circuits
- [ADDED] two phase short-circuit current calculation
- [ADDED] tests for short circuit currents with validation against DIgSILENT PowerFactory