edge feature

[cshjin]

Keys are associated with edges

• branch
• gmd_branch
• (optional) branch_gmd
• (optional) branch_thermal

*[ ] finalize the edge features for branch and gmd_branch

[cshjin]

branch edge feature

column	type	description
fbus	int	"from" bus number
tbus	int	"to" bus number
r	float	resistance
x	float	reactance
b	float	total line charging susceptance
rateA	float	MVA rating A (long term rating), set to 0 for unlimited
rateB	float	MVA rating B (short term rating), set to 0 for unlimited
rateC	float	MVA rating C (emergency rating), set to 0 for unlimited
ratio	float	TAP: transformer off nominal turns ratio
angle	float	SHIFT: transformer phase shift angle (degrees)
status	binary	initial branch status, 1: in-service, 0: out-of-service
angmin	float	minimum angle difference
angmax	float	maximum angle difference

• fbus and tbus are matched with the bus number in bus
  • [x] remove both of them from feature
  • [x] (TODO) convert the (fbus, tbus) as the edges in the graph

  • 4 handles this problem.

• Overall, branch has 11 edge features

[cshjin]

gmd_branch edge feature

columns	dtype	description
f_bus	int	"from" bus in the gmd bus table
t_bus	int	"to" bus in the gmd bus table
parent_index	int	index of corresponding ac network branch
br_status	binary	binary value that defines the status of branch (1: enabled, 0: disabled)
br_r	float	branch resistance (in unit of Ohms)
br_v	float	induced quasi-dc voltage (in unit of Volts)
len_km	float	length of branch (in unit of km) optional
name	string	a descriptive name for the branch

Need domain knowledge:

• fbus and tbus are matched with the bus number in bus

  • [ ] the pair (fbus, tbus) are not the same as the ones in branch. What's the meaning here?
  • [x] remove both of them from features

• (TODO) parent_index ac network branch? another type of network? It looks like it is associated with bus (node id).

• (TODO) name: do we need to extract the additional features from the name, say hi, lo?

• (TODO) the length of this table is not the same as the branch table. What are the additional settings from the table?

• Overall, gmd_branch has 4 edge features

[cshjin]

branch_gmd edge features

columns	dtype	description
hi_bus	int	index of high-side ac network bus
lo_bus	int	index of low-side ac network bus
gmd_br_hi	int	index of gmd branch corresponding to high-side winding (for two-winding transformers)
gmd_br_lo	int	index of gmd branch corresponding to low-side winding (for two-winding transformers)
gmd_k	float	scaling factor to calculate reactive power consumption as a function of effective winding current (in per-unit)
gmd_br_series	int	index of gmd branch corresponding to series winding (for auto-transformers)
gmd_br_common	int	index of gmd branch corresponding to common winding (for auto-transformers)
baseMVA	float	MVA base of transformer
type	string	type of branch -- "xfmr" / "transformer", "line", or "series_cap"
config	string	winding configuration of transformer -- currently "delta-delta", "delta-wye", "wye-delta", "wye-wye", "delta-gwye", "gwye-delta", "gwye-gwye", and "gwye-gwye-auto" are supported

• hi_bus and lo_bus matches with the number in bus
  • [ ] (TODO) are these the same as the edge index? Need some domain knowledge. Ref: #4
• (TODO) gmd_br_hi and gmd_br_lo are not complete pairs, (-1, -1), (u, -1), (u, v), what are those meanings? Need some domain knowledge.
• (TODO) gmd_k = -1 what's the meaning of this, missing value? or inactive? Need some domain knowledge.
  • same question with gmd_br_series , gmd_br_common, and baseMVA
• [x] convert type into one-hot vector encoders: three types
• [x] convert 'config' into one-hot vector encoders: nine configs
• Overall, branch_gmd has 16 edge features

[cshjin]

(Optional) branch_thermal edge_feature

columns	dtype	description
xfmr	binary	binary value that defines if branch is a transformer (1: transformer, 0: not a transformer)
temperature_ambient	float	ambient temperature of transformer (in unit of Celsius)
hotspot_instant_limit	float	1-hour hot-spot temperature limit of transformer (in unit of Celsius)
hotspot_avg_limit	float	8-hour hot-spot temperature limit of transformer (in unit of Celsius)
hotspot_rated	float	hot-spot temperature-rise of transformer at rated power (in unit of Celsius)
topoil_time_const	float	top-oil temperature-rise time-constant of transformer (in unit of minutes)
topoil_rated	float	top-oil temperature-rise of transformer at rated power (in unit of Celsius)
topoil_init	float	initial top-oil temperature of transformer (in unit of Celsius)
topoil_initialized	binary	binary value that defines the initial top-oil temperature of transformer (1: temperature starts with topoil_init value, 0: temperature starts with steady-state value)
hotspot_coeff	float	relationship of hot-spot temperature rise to Ieff (in unit of Celsius/Amp)

Need some domain knowledge:

• [ ] where is the fbus and tbus on this table? How to extract the edges, are those aligned with the branch_id in branch? ref: https://github.com/cshjin/swmp_ml/issues/3#issuecomment-1295291286
• [ ] is -1 in features columns means missing values?
• Overall, branch_thermal has 10 edge features.

[cshjin]

Close for now.

(option) we can select a couple of features as relevant features to the blocker placement problems.