The Federal Energy Regulatory Commission last week approved a new reliability standard that will allow PJM and other transmission planners to plan for “non-consequential” load loss following a single contingency.

The rules, part of the North American Electric Reliability Corp.’s Transmission Planning Reliability Standard (TPL-001-4), includes limitations on the maximum amount of load that an entity may plan to shed, a stakeholder process and safeguards to ensure the rules are applied consistently. Use of such load losses “should be rare,” the commission said.

The new standard limits permissible non-consequential load losses to 75 MW. Planned load losses between 25 MW and 75 MW, or any planned loss at the 300 kV level or above would receive greater scrutiny by regulatory authorities and NERC.

In these cases, “the Transmission Planner or Planning Coordinator must ensure that applicable regulatory authorities or governing bodies responsible for retail electric service issues do not object to the use of” the load loss. Planners must also submit the information to NERC, which will determine whether there are any adverse reliability impacts from the plan.

The commission rejected a request from MISO that it define “regulatory authorities” that must be consulted. “Because each state and locality has different entities that are responsible for reliability of retail electric service, we are reluctant to further define who may participate,” the commission wrote.

The commission had rejected NERC’s previous attempts to write rules on the issue, saying they were too vague.

“I am pleased that we are putting behind us one of the most difficult outstanding issues dating from the commission’s March 2010 reliability orders,” Commissioner Cheryl LaFleur said in a statement. “This case was an example in which NERC and the industry proposed an `equally efficient and effective’ alternative solution to address a concern articulated by the commission.”

The Commission required NERC to submit a report based on the first two years of implementation of the new standard.

The new NERC standard also requires annual assessments addressing steady state, short circuit and stability conditions.

The Commission ordered NERC to make two changes to the standard. One modification will address concerns that it could exclude planned maintenance outages of significant facilities from planning assessments. The other will change the TPL-001-4, Requirement R1 Violation Risk Factor from medium to high.