FERC Order No. 901 – Milestone 3, Part 1: Modeling and
Data Sharing Requirements addresses regulatory directives from the NERC Standards Development
Work Plan to respond to FERC Order No. 901. This project is
intended to establish new or revised Reliability Standards to ensure the usage
of a uniform framework for data sharing and model development. This uniform
framework is to ensure the directives of Order No. 901 can be effectively met
to ensure usage of generic model types for IBR in the Interconnection-wide
models.
This project must ensure modeling revisions from other IBR performance
requirements in other 901-related projects will utilize the uniform framework.
For instance, performance of IBR during an event (grid disturbance) are
identified and corrected within Milestone 2 of FERC Order No. 901. Evaluated
performance within new PRC-029 or PRC-030 may necessitate some form of change
to how specific IBR are represented in the model; as the IBR should be modeled
based on how it performs during a disturbance or and new/changed equipment as a
result of failing to ride through. However, any requisite changes to model data
as a result of correcting IBR performance, must be communicated through a
uniform model framework to assure all impacted entities and users of the approved
models are adequately informed and provided updated models (as developed within
this project). This project, Milestone 3 Part 1, will establish the uniform
framework for data sharing and model development of future Order No. 901
related projects that will utilize performance data.
This project has been identified as higher priority at this time. The project has a FERC deadline of November 4, 2025.
Standard(s) Affected: MOD-032-X, IRO-010, and TOP-003
Background for Phase II
The TPL-001 SARs are Phase II for Project 2022-02 and is not expected to be a high priority project. While the current Drafting Team (DT) of Project 2022-02 is working on the project, a new SAR related to TPL-001-5.1 was approved for posting by the Standards Committee (SC). The SC asked the current SDT to include this SAR as part of the project rather than creating a new project. The new SAR will address Footnote 13d issue in Standard TPL-001-5.1.
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)
Standard(s) Affected: TPL-001-5.1 and MOD-032-1
Purpose/Industry Need
The NERC TPL-001-4 Reliability Standard was revised to TPL-001-5.1 (subject to Enforcement July 1, 2023), which expanded Footnote 13 from specific Protection System relays to include communication systems, station DC supply, and control circuitry. More specifically, Footnote 13.d now applies to control circuitry from the DC supply through and including the circuit breaker trip coil. However, the footnote only provides an exclusion for a single (non-redundant) monitored and reported trip coil, but not the control circuit itself.
By only excluding the trip coil and not permitting the control circuitry to be excluded, it implies that the remainder of the Protection System control circuitry is not excluded, even if it is monitored and reported. For example, it is very common to install trip circuit monitoring which monitors the control circuitry and the trip coil, but the trip coil is the only component that qualifies for the TPL-001-5.1 exclusion.
Modifying the Footnote 13.d exception to apply to any monitored and reported components of the control circuitry to be consistent with Protection System design and operational functionality will allow the DP, GO, and TO to achieve the required transmission performance mandated by TPL-001-5.1 in a much more efficient manner.
The original TPL-001-5 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.
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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: https://www.nerc.com/comm/PC/InverterBased%20Resource%20Performance%20Task%20Force%20IRPT/Review_of_NERC_Reliability_Standards_White_Paper.pdf
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.
