Distribution loss factors are calculated each hour using the Levenberg–Marquardt algorithm (commonly referred to as "LM"). LM was first published in 1944. This is the same algorithm the Regional Transmission Organizations use to solve their state estimators and calculate hourly losses on their transmission systems.
Each day, a five day real time distribution loss factor forecast is produced and made available for download via the Losses and System Load page on Ameren's RES Portal website. On that same page, actual real time distribution loss factors are made available for download 7, 14, 55, and 105 days after each operating day.
A PLC is a given service point’s contribution to the MISO coincident peak. Each PLC is inclusive of distribution losses, transmission losses, and planning reserve margin. The transmission loss factor and planning reserve margin used for each planning year's set of PLCs are calculated by MISO.
Currently, Ameren calculates PLCs once per year in December. These PLCs then become effective June 1st of the following year. Any new service point that is created after PLC calculations are made gets a PLC assignment of zero until the next set of PLC calculations become effective. For example, if a service point is created in January of 2018, then the earliest that it would have a non-zero PLC is June of 2019.
When a service point is terminated, the PLC assigned to that service point still has to be accounted-for from a MISO-reporting perspective through the end of the MISO planning year (May 31st). In addition, if a PLC for a service point has been calculated for the following MISO planning year, then that PLC must be accounted for through the end of the following MISO planning year. The MISO Asset Owner with which the PLC was reported as of the time that the service point was terminated will continue to "own" the PLC through the end of the MISO planning year(s).
For example, let's say that a service point has a PLC of 100 kW and is assigned to MISO Asset Owner ABC when the service point is terminated on 01-10-18. Unless the service point is reactivated and assigned to a different MISO Asset Owner, MISO Asset Owner ABC will retain responsibility for this service point's 100 kW PLC through the end of the current MISO planning year (05-31-18). In addition, since PLCs for the following planning year (06-01-18 – 05-31-19) were calculated in December 2017, this same service point would already have a PLC assignment for the 06-01-18 – 05-31-19 MISO planning year. Unless the service point is reactivated and assigned to a different MISO Asset Owner, Asset Owner ABC would be responsible for the service point's 06-01-18 – 05-31-19 PLC through 05-31-19.