add Electrical CIM quantityKinds and units

[VladimirAlexiev]

Electrical CIM needs some new quantityKinds and units:

QuantityKind	Unit1	Unit2
ActivePowerPerCurrentFlow	W-PER-A	MegaW-PER-A
ActivePowerPerFrequency	W-PER-HZ	MegaW-PER-HZ
ActivePowerChangeRate	W-PER-SEC	MegaW-PER-SEC
VoltagePerReactivePower	V-PER-V-A_Reactive	KiloV-PER-V-A_Reactive

@Sveino or @gridDigIt (@griddigit-ci) can you dig out the definitions from CIM, then define dimension vectors and other attributes?
I think the conversion factor will be 1 for Unit1, and 1e6/1e3 for Unit2.

[steveraysteveray]

@VladimirAlexiev, your second row looks suspicious, because frequency is inverse time, so the unit would be Watt*Second.

[VladimirAlexiev]

You can find it at
https://cim.fein-aachen.org/libcimpp/doc/IEC61970_17v23/classIEC61970_1_1Base_1_1Domain_1_1ActivePowerPerFrequency.html (not authoritative, but same as authoritative).

Definition is "Active power variation with frequency" (I don't pretend to understand what that is).

Unit is "Wpers" which is CIM way's of spelling W-PER-SEC.

[VladimirAlexiev]

Another candidate: Sveino/Inst4CIM-KG#43.
Is ApparentPower same as ComplexPower or a sub-concept?
Electrical experts needed!

[steveraysteveray]

We have the following skos:broader hierarchy at present:

...where ComplexPower is a categorization that includes ApparentPower (the vector sum of the Active (sometimes called Real) and Reactive Power). ComplexPower also includes those two components. They all share the same dimensionality.

[VladimirAlexiev]

@steveraysteveray Thanks! I overlooked qk:ApparentPower

[steveraysteveray]

Back to my concerns about ActivePowerPerFrequency, either the name is wrong, or the corresponding unit is wrong. Think about it - Active Power is measured in Watts, Frequency is measured in Hertz - so I just don't see how the corresponding unit can be Watts per Second.

(I believe the inverse concept is known as the Droop Coefficient: The droop coefficient (often denoted as R) relates the change in frequency (Δf) to the change in active power (ΔP). This is a concept that is more easily understood. As the grid is loaded more, there is a corresponding shift in the frequency. I'm also not an electrical engineer, but I'm guessing that ActivePowerPerFrequency might be talking about how much added power is needed to restore the baseline frequency?)

Regardless, I think there's an inconsistency with the quantity kind and the unit.

[VladimirAlexiev]

@steveraysteveray

This kind is used with only one prop:
cim:ExternalNetworkInjection.governorSCD "Power Frequency Bias. This is the change in power injection divided by the change in frequency and negated. A positive value of the power frequency bias provides additional power injection upon a drop in frequency."
So indeed it must be measured in W-PER-HZ and I've corrected the table on top.

@Sveino and @griddigit-ci, when can you submit a PR? I'll map to these not-yet-existing QUDT URLs.

[VladimirAlexiev]

@Sveino and @griddigit-ci, when can you submit a PR? These not-yet-existing QUDT URLs are now used in CIM:
https://github.com/Sveino/Inst4CIM-KG/tree/develop/rdfs-improved#mapping-quantitykinds-and-units