CIM Issues #5014
Handling unit multiplierNeed a policy for WG13 with respec
Description
Handling unit multiplier
Need a policy for WG13 with respect to how unit multpliers are to be exchanged. For example CDPSM has need for Length to be in km for line length, but in meter for conductor spacing. 61970-552 does not provide for exchange of unit symbols or unit multpliers. Manual documentation is required in profiles. Possibly different model parts assembled together may have diffferent unit multipliers such as combining a distribution and transmission model together.
Proposed Solution
Simplistic solution is to align on one mutiplier (say 1) and only exchange meter, using the decimal in the actual exchange to express the value properly. This puts more stress on a user interface presenting the data differently than how it is exchanged.
Assign to Units of Measure Subgroup
Decision
Oslo 14 June 2023
Considering that we expect to have models that include distribution and transmission grids, the recommendation is to remove multipliers in the profiles. It will be a breaking change.
There are 3 ways how to implement this:
1) delete .multiplier from the canonical UML. This implies that the multiplier is 1. This needs discussion with other TFs
2) fix the .multiplier to "none" in the canonical UML. This means that the multiplier is 1. This needs discussion with other TFs
3) fix the .multiplier to "none" in the profile, which means we need to pay attention when creating profiles so that all profiles are consistent. The advantage of this option is that there could be different approaches between different TFs
Preferred option is option 1, but due to 61850 harmonization perhaps option 2 is better.
TF13 may implement option 3 first.
This will not apply to hours, minutes, seconds
An email will need to be sent to WG13 to check the support for this agreement.
TF13, call 12-Jul-2023:
- Agreed to apply option 3 for all TF13 profiles for CIM18
- Before closing the issue make sure there is a joint issue to inform other TFs
Release Notes
All profiles are updated to have "none" as multiplier in the CIMDatatype. This means that values are exchanged in their base SI unit and will need to use engineering notation, e.g. SwPowerFlow.p in SV profile was defined as MW and 100.6 MW are exchanged in xml as <SvPowerFlow.p>100.6<SvPowerFlow.p>. After the change in the profiles the instance data is <SvPowerFlow.p>100.6E6<SvPowerFlow.p>
The following changes are applied:
- in EQ profile - 452 and 600: ActivePower, ActivePowerPerCurrentFlow, ActivePowerPerFrequency, ApparentPower, Length, ReactivePower
, RealEnergy, Voltage
- in SC profile - 452 and 600: ActivePower, Length, Voltage
- in SSH - 456 and 600: ActivePower, ApparentPower, ReactivePower, RealEnergy, Voltage
- in SV profile 0 456 and 600: ActivePower, ReactivePower, Voltage
IEC 61970-457 Ed2 is not updated as it is in FDIS. Most probably an amendment will need to be launched after the approval of the FDIS
Updated by Eric Stephan about 3 years ago
- Subject changed from Handling unit multiplier Need a policy for WG13 with respec to Handling unit multiplierNeed a policy for WG13 with respec
- Decision updated (diff)
Updated by Eric Stephan almost 3 years ago
Updated by Chavdar Ivanov over 1 year ago
- Status changed from Open to Review
- Decision updated (diff)
- CIM Keywords 61970-Domain added
- CIM Impacted Groups WG14, WG16 added
Updated by Chavdar Ivanov about 1 year ago
- Solution to be Applied To set to CIM18v07
- Solution Version set to CIM18v07
- Solution Applied By set to Chavdar Ivanov
- Completion Date set to 10/14/2023
- Breaking Change changed from No to Yes
- Breaking Change Description set to Profiles are updated and applications need to update the multipliers