Utilities in the territories of the Midwest Reliability Organization and SERC Reliability will pay a total of $186,000 in penalties to the regional entities for violations of NERC’s reliability standards under two settlements approved by FERC.
NERC filed the settlements on July 31, along with an additional settlement for infringement of the ERO’s critical infrastructure protection (CIP) standards whose details were not made public in accordance with NERC and FERC’s policy on CIP violations. The commission said in an Aug. 29 filing that it would not further review the settlements, leaving the penalties intact.
MRO’s settlement involves the Grande Prairie Wind Farm (GPW), a 400-MW facility in Holt County, Neb., owned by Berkshire Hathaway Energy subsidiary BHE Renewables (NP25-14). Power generated at the wind farm is sold to Omaha Public Power District under a long-term power purchase agreement.
According to the settlement agreement, GPW notified MRO in a quarterly report on July 17, 2023, that it was in violation of FAC-003-4 (Transmission vegetation management) in its capacity as a generator owner. The utility had experienced a C-phase to ground fault on a 345-kV generation tie-line between the wind farm and a facility owned by another entity. The fault caused the main generator supply breaker at GPW, as well as two breakers at the other entity’s facility, to trip open, which cleared the fault on the tie-line.
GPW investigated the cause and discovered “a tree that demonstrated damage from contacting the overhead C-phase line.” The utility cut back the tree and other plants nearby, visually inspected the rest of the line, and returned it to service.
MRO attributed the violation to a lack of adequate controls to prevent encroachments into the minimum vegetation clearance distance of the tie-line that could cause a sustained outage, as required by requirement R2.4 of FAC-003-4. The RE assessed the risk as moderate because, while the vegetation encroachment caused a sustained outage and exposed the 345-kV transmission system to a fault, the facility is not a networked transmission facility or black start resource, so a trip “would not have a significant impact on the” electric grid.
After removing the tree and other encroaching plants, GPW’s additional mitigation actions include increasing the frequency of vegetation inspection at the wind farm to at least twice a year, with the 15-foot MVCD to be documented with photographs. The GO also updated its FAC-003 program to reflect the new inspection schedule and conducted training on the standard.
Mississippi Power Discovers Rating Mishap
In the other settlement approved by FERC, Southern Co. subsidiary Mississippi Power agreed to pay $86,000 to SERC (NP25-15). The penalty stemmed from violations of FAC-008-5 (Facility ratings) and its predecessor FAC-009-1 (Establish and communicate facility ratings) reported to the RE on June 3, 2022.
According to NERC’s monthly spreadsheet notice of penalty, where the settlement was filed, Mississippi Power discovered a discrepancy on Jan. 4, 2022, between its records of equipment installed at a 230-kV substation and those found in the field. The utility was examining the facility in response to a data request from SERC in advance of an on-site audit.
Mississippi Power’s drawings and database for the substation indicated the 230-kV line should be equipped with bundled aluminum conductor steel-reinforced (ACSR) cable jumpers rated at 2,808 amps, with the most limiting element (MLE) being the ACSR conductor, rated at 1,512 amps. However, the field verification found that one set of jumpers actually was single all-aluminum conductor (AAC) jumpers rated at 1,496 amps. This meant that the AAC jumpers should have been identified as the MLE, and therefore the facility rating was incorrect.
After discovering this issue and derating the facility, Mississippi Power conducted walkdowns of all 108 transmission substations, 106 of which were completed by March 31. During this time, Southern began a system-wide initiative to implement a common transmission facility ratings database across all operating companies. This involved a quality assurance review by each company of the data for the new database.
Because of the walkdowns and QA assessment, Mississippi Power found 15 total instances where incorrect element ratings resulted in an incorrect MLE, leading to incorrect facility ratings at eight different 115-kV and 230-kV stations. The misratings required derates of up to 44%. None of the stations were found to have operated above the correct ratings.
The utility also discovered 239 instances of incorrect element ratings on 115-kV, 230-kV and 500-kV facilities that did not impact the MLE or facility rating. Mississippi Power has committed to finishing the remaining walkdowns by Dec. 31.
SERC said the cause of the infringement was “inadequate change management controls and legacy equipment identification controls.” The violation began on June 18, 2007, when FAC-009-1 became enforceable, and should end Dec. 31, when the utility has completed the walkdowns and updated all incorrect equipment and facility ratings.

