Project 2022-02 Modifications to TPL-001-5.1 and MOD-032-1
Related Files​


The comment and nomination period for the Project 2022-02 Modifications to TPL-001-5.1 and MOD-032-1 Standard Authorization Requests concluded at 8 p.m. Eastern, Wednesday, March 02, 2022.

​The Standards Committee is expected to appoint members to the drafting team in April 2022. Nominees will be notified shortly after they have been appointed. Once a drafting team is formed, the comments will be reviewed and the next steps of the project determined.

Many areas of the North American bulk power system (BPS) continue to experience an increase in BPS-connected inverter-based resources (e.g., wind, solar photovoltaic (PV), battery energy storage systems (BESS), and hybrid power plants). NERC Reliability Standard TPL-001-5.1 is a foundational standard used for “establishing transmission system performance requirements within the planning horizon to develop a bulk electric system (BES) that will operate reliably over a broad spectrum of system conditions and following a wide range of probable contingencies." Transmission Planners (TPs) and Planning Coordinators (PCs) develop and use models of the electrical grid to perform planning assessments (e.g., steady-state, dynamic, and short-circuit) to develop corrective action plans for future reliability issues identified. Ensuring that the TPL-001 standard is reflective of the evolving nature of the BPS and its resource mix is paramount to ensuring reliable operation and resilience of the BPS moving forward.

The NERC Inverter-Based Resource Performance Task Force (IRPTF)[1] undertook a complete review of the NERC Reliability Standards in the context of increasing levels of BPS-connected inverter-based resources and published a white paper on the outcomes and recommendations of this review in March 2020.[2]

Based on the outcome of the review, it was determined that the TPL-001-4/5[3] needed clarifications “to address terminology throughout the standard that is unclear with regards to inverter-based resources" the next time the standard is revised.

Considering current trends, the NERC SPIDERWG undertook a review of the TPL-001 standard considering the potential impact of distributed energy resources (DERs).  This review is captured in the following RSTC-approved white paper and serves as the technical justification for the revisions suggested in this SAR:

  • SPIDERWG: Assessment of DER impacts on NERC Reliability Standard TPL-001 (here)

This SAR proposes to update TPL-001-5.1 to address some of the issues identified in the white paper.

TPL-001-5.1 does not currently require Planning Coordinators and Transmission Planners to complete Planning Assessments with adequate representation of the dynamic behavior of DERs. As the penetration of DERs increases, and based on the DER data and models available, Planning Assessments should include DERs that can potentially impact Transmission System performance assessment.  NERC's “Lesson Learned: Single Phase Fault Precipitates Loss of Generation and Load", evaluating a 2019 frequency event in Southern England exacerbated by the unexpected reduction of 725 MW of IBR output and the unexpected loss of 350 MW of DER, highlights the critical importance of accurate Transmission System Planning Assessments.  In July 2020, a significant quantity of solar PV facilities across a large geographic area in Southern CA reduced about 1000 MW output due to a disturbance on the bulk power system. Subsequent event analysis revealed that it was the consequence of momentary cessation and slow recovery of power. Standards enhancement has been one of the recommendations after the event analysis to ensure reliable operation of the bulk power system.

As the penetration of DERs continues to increase across the North American bulk power system (BPS), it is necessary to account for the potential impacts of DERs on reliability in the planning, operation, and design of the BES. The NERC System Planning Impacts of Distributed Energy Resources Working Group (SPIDERWG) has identified the need for improved modeling of aggregate DER for planning studies (including both utility-scale and retail-scale DER) conducted by Transmission Planners (TPs) and Planning Coordinators (PCs). MOD-032-1 addresses the gathering of modeling data to perform planning assessments but the standard currently has no specific reference to DER data. This SAR proposes to update MOD-032-1 to: (1) include “data requirements and reporting procedures"[4] for DER that are necessary to support the development of accurate interconnection-wide models, (2) replace Load-Serving Entity (LSE) with Distribution Provider (DP) because of the removal of LSEs from the NERC registry criteria, and (3) enable the SDT to review any additional gaps in DER data collection with the de-registration of LSE.

Standard(s) Affected: TPL-001-5.1 and MOD-032-1

Purpose/Industry Need
This SAR revises requirements within the TPL-001-5 standard to provide clarity and consistency for how BPS-connected inverter-based resources are considered, modeled, and studied in planning assessments. The proposed revisions to TPL-001-5 will ensure industry is effectively and efficiently conducting planning assessments and that the requirements are equally suitable for inverter-based resources as they are for synchronous generation.

The purpose of this SAR is to revise requirements to provide clarity, or in some cases, expand the scope of requirements when considering the performance of DERs to ensure the accuracy of Transmission System Planning Assessments.

This SAR proposes to revise MOD-032-1 to address gaps in data collection for the purposes of modeling aggregate levels of DERs in planning assessments. The goal is to provide clarity and consistency for data collection across PCs and TPs when coordinating with the DP to gather aggregate load and aggregate DER data.

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1 The IRPTF has subsequently become the IRPWG under the NERC Reliability and Security Technical Committee (RSTC).

2 NERC IRPTF, “IRPTF Review of NERC Reliability Standards," March 2020:

3 At the time of review, the TPL-001-5 standard had just recently been approved by FERC and was yet to be subject to enforcement.

4 See Requirement R1 of MOD-032-1, which requires each TP and PC to develop data requirements and reporting procedures for the collection of modeling data used for the development of models for each PC footprint.​

DraftActionsDatesResultsConsideration of Comments
TPL-001-5.1 IRPWG SAR​
Clean | Redline
Clean | Redline

​MOD-032-1 SAR
Clean | Redline​

The Standards Committee accepted these SARs on September 21, 2022

Drafting Team Nominations

Supporting Materials

Unofficial Nomination Form (Word) 

Nomination Period


Submit Nominations​

02/01/2022 – 03/02/2022



MOD-032-1 SAR​


Supporting Materials​​

Unofficial Comment Form (Word)​

Comment Period


Submit Comments​

​​​​02/01/2022 – 03/02/2022


Comments Received​