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pdfMOD‐001‐2 — Modeling, Data, and Analysis — Available Transmission System Capability
A. Introduction
1.
Title:
Available Transmission System Capability
2.
Number:
MOD‐001‐2
3.
Purpose:
To ensure that determinations of available transmission system capability are
determined in a manner that supports the reliable operation of the Bulk‐Power
System (BPS) and that the methodology and data underlying those determinations are
disclosed to those registered entities that need such information for reliability
purposes.
4.
Applicability:
4.1. Functional Entity
4.1.1 Transmission Operator
4.1.2 Transmission Service Provider
4.2. Exemptions: The following is exempt from MOD‐001‐2.
4.2.1 Functional Entities operating within the Electric Reliability Council of
Texas (ERCOT)
5.
Effective Date:
5.1. The standard shall become effective on the first day of the first calendar quarter
that is 18 months after the date that the standard is approved by an applicable
governmental authority or as otherwise provided for in a jurisdiction where
approval by an applicable governmental authority is required for a standard to
go into effect. Where approval by an applicable governmental authority is not
required, the standard shall become effective on the first day of the first
calendar quarter that is 18 months after the date the standard is adopted by the
NERC Board of Trustees or as otherwise provided for in that jurisdiction.
Page 1 of 17
MOD‐001‐2 — Modeling, Data, and Analysis — Available Transmission System Capability
B. Requirements and Measures
R1.
Each Transmission Operator that determines Total Flowgate Capability (TFC) or Total Transfer
Capability (TTC) shall develop a written methodology (or methodologies) for determining TFC or TTC
values. The methodology (or methodologies) shall reflect the Transmission Operator’s current
practices for determining TFC or TTC values. [Violation Risk Factor: Lower] [Time Horizon: Operations
Planning]
1.1 Each methodology shall describe the method used to account for the following limitations in
both the pre‐ and post‐contingency state:
1.1.1
Facility ratings;
1.1.2
System voltage limits;
1.1.3
Transient stability limits;
1.1.4
Voltage stability limits; and
1.1.5
Other System Operating Limits (SOLs).
1.2 Each methodology shall describe the method used to account for each of the following
elements, provided such elements impact the determination of TFC or TTC:
1.2.1
The simulation of transfers performed through the adjustment of generation, Load, or
both;
1.2.2
Transmission topology, including, but not limited to, additions and retirements;
1.2.3
Expected transmission uses;
1.2.4
Planned outages;
1.2.5
Parallel path (loop flow) adjustments;
1.2.6
Load forecast; and
1.2.7
Generator dispatch, including, but not limited to, additions and retirements.
1.3 Each methodology shall describe the process for including any reliability‐related constraints that
are requested to be included by another Transmission Operator, provided that (1) the request
references this specific requirement, and (2) the requesting Transmission Operator includes
those constraints in its TFC or TTC determination.
1.3.1 Each Transmission Operator that uses the Flowgate Methodology shall include in its
methodology an impact test process for including requested constraints. If a generator to
Load transfer in a registered entity’s area or a transfer to a neighboring registered entity
impacts the requested constraint by five percent or greater, the requested constraint
shall be included in the TFC determination, otherwise the requested constraint is not
required to be included.
1.3.2 Each Transmission Operator that uses the Area Interchange or Rated System Path
Methodology shall describe in its methodology the process it uses to account for
requested constraints that have a five percent or greater distribution factor for a transfer
Page 2 of 17
MOD‐001‐2 — Modeling, Data, and Analysis — Available Transmission System Capability
between areas in the TTC determination; otherwise the requested constraint is not
required to be included. When testing transfers involving the requesting Transmission
Operator’s area, the requested constraint may be excluded.
1.3.3 A different method for determining whether requested constraints need to be included
in the TFC or TTC determination may be used if agreed to by the Transmission Operators.
M1. Each Transmission Operator that determines TFC or TTC shall provide its current written
methodology (or methodologies) or other evidence (such as written documentation) to show that its
methodology (or methodologies) contains the following:
A description of the method used to account for the limits specified in part 1.1. Methods of
accounting for these limits may include, but are not limited to, one or more of the following:
o TFC or TTC being determined by one or more limits.
o Simulation being used to find the maximum TFC or TTC that remains within the limit.
o The application of a distribution factor in determining if a limit affects the TFC or TTC value.
o Monitoring a subset of limits and a statement that those limits are expected to produce the
most severe results.
o A statement that the monitoring of a select limit(s) results in the TFC or TTC not exceeding
another set of limits.
o A statement that one or more of those limits are not applicable to the TFC or TTC
determination.
A description of the method used to account for the elements specified in part 1.2, provided such
elements impact the determination of TFC or TTC. Methods of accounting for these elements
may include, but are not limited to, one or more of the following:
o A statement that the element is not accounted for since it does not affect the determination
of TFC or TTC.
o A description of how the element is used in the determination of TFC or TTC.
R2.
A description of the process for including any reliability‐related constraints that are requested to
be included by another Transmission Operator, as specified in parts 1.3, 1.3.1, 1.3.2, or 1.3.3).
Each Transmission Operator that determines TFC or TTC shall provide evidence that currently
active TFC or TTC values were determined based on its current written methodology, as specified
in Requirement R1.
Each Transmission Service Provider that determines Available Flowgate Capability (AFC) or Available
Transfer Capability (ATC) shall develop an Available Transfer Capability Implementation Document
(ATCID) that describes the methodology (or methodologies) for determining AFC or ATC values. The
methodology (or methodologies) shall reflect the Transmission Service Provider’s current practices
for determining AFC or ATC values. [Violation Risk Factor: Lower] [Time Horizon: Operations
Planning]
Page 3 of 17
MOD‐001‐2 — Modeling, Data, and Analysis — Available Transmission System Capability
2.1. Each methodology shall describe the method used to account for the following elements,
provided such elements impact the determination of AFC or ATC:
2.1.1.
The simulation of transfers performed through the adjustment of generation, Load, or
both;
2.1.2.
Transmission topology, including, but not limited to, additions and retirements;
2.1.3.
Expected transmission uses;
2.1.4.
Planned outages;
2.1.5.
Parallel path (loop flow) adjustments;
2.1.6.
Load forecast; and
2.1.7.
Generator dispatch, including, but not limited to, additions and retirements.
2.2. Each Transmission Service Provider that uses the Flowgate Methodology shall, for reliability‐
related constraints identified in part 1.3, use the AFC determined by the Transmission Service
Provider for that constraint.
M2. Each Transmission Service Provider that determines AFC or ATC shall provide its current ATCID or
other evidence (such as written documentation) to show that its ATCID contains the following:
A description of the method used to account for the elements specified in part 2.1, provided such
elements impact the determination of AFC or ATC. Methods of accounting for these elements
may include, but are not limited to, one or more of the following:
o A description of how the element is used in the determination of AFC or ATC.
o A statement that the element is not accounted for since it does not affect the determination
of AFC or ATC.
o A statement that the element is accounted for in the determination of TFC or TTC by the
Transmission Operator, and does not otherwise affect the determination of AFC or ATC.
For each Transmission Service Provider that uses the Flowgate Methodology, a description of the
method in which AFC provided by another Transmission Service Provider was used for the
reliability‐related constraints identified in part 1.3.
Each Transmission Service Provider that determines AFC or ATC shall provide evidence that
currently active AFC or ATC values were determined based on its current written methodology, as
specified in Requirement R2.
R3. Each Transmission Service Provider that determines Capacity Benefit Margin (CBM) values shall
develop a Capacity Benefit Margin Implementation Document (CBMID) that describes its method for
determining CBM values. The method described in the CBMID shall reflect the Transmission Service
Provider’s current practices for determining CBM values. [Violation Risk Factor: Lower] [Time
Horizon: Operations Planning]
Page 4 of 17
MOD‐001‐2 — Modeling, Data, and Analysis — Available Transmission System Capability
M3. Each Transmission Service Provider that determines CBM shall provide evidence, including, but
not limited to, its current CBMID, current CBM values, or other evidence (such as written
documentation, study reports, or supporting information) to demonstrate that it determined CBM
values consistent with its methodology described in the CBMID. If a Transmission Service Provider
does not maintain CBM, examples of evidence include, but are not limited to, an attestation,
statement, or other documentation that states the Transmission Service Provider does not
maintain CBM.
R4. Each Transmission Operator that determines Transmission Reliability Margin (TRM) values shall
develop a Transmission Reliability Margin Implementation Document (TRMID) that describes its
method for determining TRM values. The method described in the TRMID shall reflect the
Transmission Operator’s current practices for determining TRM values. [Violation Risk Factor:
Lower][Time Horizon: Operations Planning]
M4. Each Transmission Operator that determines TRM shall provide evidence including, but not limited
to, its current TRMID, current TRM values, or other evidence (such as written documentation,
study reports, or supporting information) to demonstrate that it determined TRM values
consistent with its methodology described in the TRMID. If a Transmission Operator does not
maintain TRM, examples of evidence include, but are not limited to, an attestation, statement, or
other documentation that states the Transmission Operator does not maintain TRM.
R5. Within 45 calendar days of receiving a written request that references this specific requirement
from a Planning Coordinator, Reliability Coordinator, Transmission Operator, Transmission
Planner, Transmission Service Provider, or any other registered entity that demonstrates a
reliability need, each Transmission Operator or Transmission Service Provider shall provide:
[Violation Risk Factor: Lower] [Time Horizon: Operations Planning]
5.1.
A written response to any request for clarification of its TFC or TTC methodology, ATCID,
CBMID, or TRMID. If the request for clarification is contrary to the Transmission Operator’s
or Transmission Service Provider’s confidentiality, regulatory, or security requirements
then a written response shall be provided explaining the clarifications not provided, on
what basis and whether there are any options for resolving any of the confidentiality,
regulatory, or security concerns.
5.2.
If not publicly posted on OASIS or its company website, the Transmission Operator’s
effective:
5.2.1 TRMID; and
5.2.2 TFC or TTC methodology.
5.3.
If not publicly posted on OASIS or its company website, the Transmission Service Provider’s
effective:
5.3.1 ATCID; and
5.3.2 CBMID.
Page 5 of 17
MOD‐001‐2 — Modeling, Data, and Analysis — Available Transmission System Capability
M5. Examples of evidence include, but are not limited to:
Dated records of the request and the Transmission Operator’s or Transmission Service
Provider’s response to the request;
A statement by the Transmission Operator or Transmission Service Provider that they have
received no requests; or
A statement by the Transmission Operator or Transmission Service Provider that they do not
determine one or more of these values: AFC, ATC, CBM, TFC, TTC or TRM.
R6. Each Transmission Operator or Transmission Service Provider that receives a written request from
another Transmission Operator or Transmission Service Provider for data related to AFC, ATC, TFC,
or TTC determinations that (1) references this specific requirement, and (2) specifies that the
requested data is for use in the requesting party’s AFC, ATC, TFC, or TTC determination shall take
one of the actions below. [Violation Risk Factor: Lower] [Time Horizon: Operations Planning]
6.1. In responding to a written request for data on an ongoing basis, the Transmission Service
Provider or Transmission Operator shall make available its data on an ongoing basis no later
than 45 calendar days from receipt of the written request. Unless otherwise agreed upon,
the Transmission Operator or Transmission Service Provider is not required to:
6.1.1 Alter the format in which it maintains or uses the data; or
6.1.2 Make available the requested data on a more frequent basis than it produces the
data and in no event shall it be required to provide the data more frequently than
once an hour.
6.2 In responding to all other data requests, each Transmission Operator or Transmission Service
Provider shall make available the requested data within 45 calendar days of receipt of the
written request. Unless otherwise agreed upon, the Transmission Operator or Transmission
Service Provider is not required to alter the format in which it maintains or uses the data.
6.3 If making available any requested data under parts 6.1 or 6.2 of this requirement is contrary
to the Transmission Operator’s or Transmission Service Provider’s confidentiality, regulatory,
or security requirements, the Transmission Operator or Transmission Service Provider shall
not be required to make available that data; provided that, within 45 calendar days of the
written request, it responds to the requesting registered entity specifying the data that is not
being provided, on what basis and whether there are any options for resolving any of the
confidentiality, regulatory or security concerns.
M6. Examples of evidence for a data request that involves providing data on an ongoing basis (6.1),
include, but are not limited to:
Dated records of a registered entity’s request, and examples of the response being met;
Dated records of a registered entity’s request, and a statement from the requestor that the
request was met (demonstration that the response was met is not required if the requestor
confirms it is being provided); or
Page 6 of 17
MOD‐001‐2 — Modeling, Data, and Analysis — Available Transmission System Capability
A statement by the Transmission Operator or Transmission Service Provider that they have
received no requests under this requirement.
Examples of evidence for all other data requests (6.2) include, but are not limited to:
Dated records of a registered entity’s request, and the response to the request;
Dated records of a registered entity’s request, and a statement from the requestor that the
request was met; or
A statement by the Transmission Operator or Transmission Service Provider that they have
received no requests under this requirement.
An example of evidence of a response by the Transmission Operator or Transmission Service
Provider that providing the data would be contrary to the registered entity’s confidentiality,
regulatory, or security requirements (6.3) is a response to the requestor specifying the data that is
not being provided, on what basis and whether there are any options for resolving any of the
confidentiality, regulatory, or security concerns.
Page 7 of 17
MOD‐001‐2 — Modeling, Data, and Analysis — Available Transmission System Capability
C. Compliance
1.
Compliance Monitoring Process:
1.1. Compliance Enforcement Authority:
As defined in the NERC Rules of Procedure, “Compliance Enforcement Authority” refers
to NERC or the Regional Entity in their respective roles of monitoring and enforcing
compliance with the NERC Reliability Standards.
1.2. Evidence Retention:
The following evidence retention periods identify the period of time a registered entity
is required to retain specific evidence to demonstrate compliance. For instances in
which the evidence retention period specified below is shorter than the time since the
last audit, the Compliance Enforcement Authority may ask the registered entity to
provide other evidence to show that it was compliant for the full time period since the
last audit.
Implementation and methodology documents shall be retained for five years.
Components of the calculations and the results of such calculations for all values
contained in the implementation and methodology documents.
o Hourly values for the most recent 14 days;
o Daily values for the most recent 30 days; and
o Monthly values for the most recent 60 days.
If a Transmission Operator or Transmission Service Provider is found non‐compliant,
it shall keep information related to the non‐compliance until mitigation is complete
and approved.
The Compliance Enforcement Authority shall keep the last audit records and all
requested and submitted subsequent audit records.
1.3. Compliance Monitoring and Assessment Processes:
“Compliance Monitoring and Assessment Processes” refers to the identification of
the processes that will be used to evaluate data or information for the purpose of
assessing performance or outcomes with the associated reliability standard.
1.4. Additional Compliance Information:
None
Page 8 of 17
MOD‐001‐2 — Modeling, Data, and Analysis — Available Transmission System Capability
Table of Compliance Elements
R #
R1
Time
Horizon
Operations
Planning
VRF
Lower
Violation Severity Levels (VSLs)
Lower VSL
Moderate VSL
High VSL
Severe VSL
Each Transmission
Operator that
determines TFC or TTC
has not described its
method for accounting
for one of the
limitations listed in
part 1.1 in its written
methodology. (1.1)
OR
Each Transmission
Operator that
determines TFC or TTC
has not described its
method for accounting
for one of the element
listed in part 1.2 in its
written methodology,
provided that element
impacts its TFC or TTC
determination. (1.2)
Each Transmission
Operator that
determines TFC or TTC
has not described its
method for accounting
for two of the
limitations listed in
part 1.1 in its written
methodology. (1.1)
OR
Each Transmission
Operator that
determines TFC or TTC
has not described its
method for accounting
for two, three, or four
elements listed in part
1.2 in its written
methodology,
provided those
elements impacts its
TFC or TTC
determination. (1.2)
Each Transmission
Operator that
determines TFC or TTC
has not described its
method for accounting
for any of the
limitations listed in
part 1.1 in its written
methodology. (1.1)
OR
Each Transmission
Operator that
determines TFC or TTC
has not described its
method for accounting
for five, six, or seven
elements of listed in
part 1.2 in its written
methodology,
provided those
elements impacts its
TFC or TTC
determination. (1.2)
OR
Each Transmission
Operator that
determines TFC or TTC
did not develop a
written methodology
for describing its
current practices for
determining TFC or
TTC values.
OR
Each Transmission
Operator that
determines TFC or TTC
developed a written
methodology for
determining TFC or
TTC but the
methodology did not
reflect its current
practices for
determining TFC or
TTC values.
Page 9 of 17
MOD‐001‐2 — Modeling, Data, and Analysis — Available Transmission System Capability
R #
Time
Horizon
VRF
Violation Severity Levels (VSLs)
Lower VSL
Moderate VSL
High VSL
Severe VSL
Each Transmission
Operator that
determines TFC or TTC
has not described the
process for including
any reliability‐related
constraints that have
been requested by
another Transmission
Operator, provided the
constraints are also
used in the requesting
Transmission
Operator’s TFC or TTC
calculation and the
request referenced
part 1.3. (1.3)
OR
Each Transmission
Operator that
determines TFC or TTC
has not used (i) an
impact test process for
including requested
constraints, (ii) a
process to account for
requested constraints
Page 10 of 17
MOD‐001‐2 — Modeling, Data, and Analysis — Available Transmission System Capability
R #
Time
Horizon
VRF
Violation Severity Levels (VSLs)
Lower VSL
R2
Operations
Planning
Lower
Moderate VSL
High VSL
that have a five
percent or greater
distribution factor for
a transfer between
areas in the TTC
determination, or (iii) a
mutually agreed upon
method for
determining whether
requested constraints
need to be included in
the TFC or TTC
determination. (1.3.1,
1.3.2, 1.3.3)
Each Transmission
Each Transmission
Each Transmission
Service Provider that
Service Provider that
Service Provider that
determines AFC or ATC determines AFC or ATC determines AFC or ATC
has not described its
has not described its
has not described its
method for accounting method for accounting method for accounting
for one of the
for two, three, or four for five, six, or seven
elements listed in part elements listed in part elements listed in part
2.1 in its written
2.1 in its written
2.1 in its written
methodology,
methodology,
methodology,
provided that element provided the elements provided the elements
impacts its AFC or ATC impact its AFC or ATC impact its AFC or ATC
determination. (2.1)
determination. (2.1)
determination. (2.1)
OR
Severe VSL
Each Transmission
Service Provider that
determines AFC or ATC
did not develop an
ATCID describing its
AFC or ATC
methodology.
OR
Each Transmission
Service Provider that
determines AFC or ATC
did not reflect its
current practices for
Page 11 of 17
MOD‐001‐2 — Modeling, Data, and Analysis — Available Transmission System Capability
R #
Time
Horizon
VRF
Violation Severity Levels (VSLs)
Lower VSL
R3
Operations
Planning
Lower
None.
Moderate VSL
None.
High VSL
Each Transmission
Service Provider that
uses the Flowgate
Methodology did not
use the AFC
determined by the
Transmission Service
Provider for reliability‐
related constraints
identified in part 1.3.
(2.2)
None.
Severe VSL
determining AFC or
ATC values in its
ATCID.
Each Transmission
Service Provider that
determines CBM
values did not develop
a CBMID describing its
method for
determining CBM
values.
OR
Each Transmission
Service Provider that
determines CBM
values did not reflect
its current practices
for determining CBM
values in its CBMID.
Page 12 of 17
MOD‐001‐2 — Modeling, Data, and Analysis — Available Transmission System Capability
R #
Time
Horizon
VRF
Violation Severity Levels (VSLs)
Lower VSL
R4
Operations
Planning
Lower
R5
Operations
Planning
Lower
None.
Moderate VSL
None.
High VSL
Severe VSL
None.
Each Transmission
Operator that
determines TRM
values did not develop
a TRMID describing its
method for
determining TRM
values.
OR
Each Transmission
Operator that
determines TRM
values did not reflect
its current practices
for determining TRM
values in its TRMID.
Each Transmission
Each Transmission
Each Transmission
Each Transmission
Operator or
Operator or
Operator or
Operator or
Transmission Service
Transmission Service
Transmission Service
Transmission Service
Provider failed to
Provider did not
Provider did not
Provider did not
respond in writing to a respond in writing to a respond in writing to a respond in writing to a
written request by one written request by one written request by one written request by one
or more of the
or more of the
or more of the
or more of the
registered entities
registered entities
registered entities
registered entities
specified in
specified in
specified in
specified in
Requirement R5 within Requirement R5 within Requirement R5 within Requirement R5.
45 calendar days from 76 calendar days from 106 calendar days
Page 13 of 17
MOD‐001‐2 — Modeling, Data, and Analysis — Available Transmission System Capability
R #
Time
Horizon
VRF
Violation Severity Levels (VSLs)
Lower VSL
R6
Operations
Planning
Lower
the date of the
request, but did
respond in writing
within 75 calendar
days.
Each Transmission
Operator or
Transmission Service
Provider did not
respond to a written
request for data by
one or more of the
registered entities
specified in
Requirement R6 by
making the requested
data available within
45 calendar days from
the date of the
request, but did
respond within 75
calendar days.
Moderate VSL
the date of the
request, but did
respond in writing
within 105 calendar
days.
Each Transmission
Operator or
Transmission Service
Provider did not
respond to a written
request for data by
one or more of the
registered entities
specified in
Requirement R6 by
making data available
within 76 calendar
days from the date of
the request, but did
respond within 105
calendar days.
High VSL
from the date of the
request, but did
respond in writing
within 135 calendar
days.
Each Transmission
Operator or
Transmission Service
Provider did not
respond to a written
request by one or
more of the registered
entities specified in
Requirement R6 by
making data available
within 106 calendar
days from the date of
the request, but did
respond within 135
calendar days.
Severe VSL
Each Transmission
Operator or
Transmission Service
Provider failed to
respond to a written
request for data by
making data available
to one or more of the
entities specified in
Requirement R6.
Page 14 of 17
Application Guidelines
D. Regional Variances
None.
E. Interpretations
None.
F. Associated Documents
None.
Guidelines and Technical Basis
Please see the MOD A White Paper for further information regarding the technical basis for
each requirement.
Rationale:
During development of this standard, text boxes were embedded within the standard to explain
the rationale for various parts of the standard. Upon BOT approval, the text from the rationale
text boxes was moved to this section.
Rationale for R1:
Total Flowgate Capability (TFC) and Total Transfer Capability (TTC) are the starting points for
the Available Flowgate Capability (AFC) and Available Transfer Capability (ATC) values. AFC and
ATC values influence Real‐time conditions and have the ability to impact Real‐time operations.
A Transmission Operator (TOP) shall clearly document its methods of determining TFC and TTC
so that any TOP or Transmission Service Provider (TSP) that uses the information can clearly
understand how the values are determined. The TFC and TTC values shall account for any
reliability‐related constraints that limit those values as well as system conditions forecasted for
the time period for which those values are determined. The TFC and TTC values shall also
incorporate constraints on external systems when appropriate, in addition to constraints on the
TOP’s own system. Requirement R1 sets requirements for the determination of TFC or TTC, but
does not establish if a TOP must determine TFC or TTC.
Rationale for R2:
A TSP must clearly document its methods of determining AFC and ATC so that TOPs or other
entities can clearly understand how the values are determined. The AFC and ATC values shall
account for system conditions at the time those values would be used. Each TSP that uses the
Flowgate Methodology shall also use the AFC value determined by the TSP responsible for an
external system constraint where appropriate. Requirement R2 sets requirements for the
determination of AFC or ATC, but does not establish if a TSP must determine AFC or ATC.
Page 15 of 17
Application Guidelines
Rationale for R3:
Capacity Benefit Margin (CBM) is one of the values that may be used in determining the AFC or
ATC value. CBM is the amount of firm transmission transfer capability preserved by the
transmission provider for Load‐Serving Entities (LSEs), whose Loads are located on that TSP’s
system, to enable access by the LSEs to generation from interconnected systems to meet
resource reliability requirements. A clear explanation of how the CBM value is developed is an
important aspect of the TSP’s ability to communicate to other entities how that AFC or ATC
value was determined. Therefore anytime CBM is used (non‐zero) a CBMID is required to
communicate the method of determining CBM.
Rationale for R4:
Transmission Reliability Margin (TRM) is one of the values that may be used in determining the
AFC or ATC value. TRM accounts for the inherent uncertainty in system conditions and the need
for operating flexibility to ensure reliable system operation as system conditions change. An
explanation by the TOP of how the TRM value is developed for use in the TSP’s determination
of AFC and ATC is an important aspect of the TSP’s ability to communicate to other entities how
that AFC or ATC value was determined. Therefore, anytime a TOP provides a non‐zero TRM to a
TSP, a Transmission Reliability Margin Implementation Document (TRMID) is required to
communicate the method of determining TRM.
Rationale for R5:
Clear communication of the methods of determining AFC, ATC, CBM, TFC, TRM, and TTC are
necessary to the reliable operation of the Bulk‐Power System (BPS). A TOP and TSP are
obligated to make available their methodologies for determining AFC, ATC, CBM, TFC, TRM, and
TTC to those with a reliability need. The TOP and TSP are further obligated to respond to any
requests for clarification on those methodologies, provided that responding to such requests
would not be contrary to the registered entities confidentiality, regulatory, or security
concerns. The purpose of this requirement is not to monitor every communication that occurs
regarding these values, but to ensure that those with reliability need have access to the
information. Therefore, the requirement is very specific on when it is invoked so that it does
not create an administrative burden on regular communications between registered entities.
Rationale for R6:
This requirement provides a mechanism for each TOP or TSP to access the best available data
for use in its calculation of AFC, ATC, CBM, TFC, TRM, and TTC values. Requirement R6 requires
that a TOP or TSP share their data, with the caveat that the TOP or TSP is not required to modify
that data from the form that they use or maintain it in. For data requests that involve providing
data on a regular interval, the TOP or TSP is not obligated to provide the data more frequently
than either (1) once an hour, or (2) as often as they update the data. The data provider is also
not obligated to provide data that would violate any of its confidentiality, regulatory, or security
obligations. The purpose of this requirement is not to monitor every data exchange that occurs
regarding these values, but to ensure that those with reliability need have access to the
information. Therefore, the requirement is very specific on when it is invoked so that it does
not create an administrative burden on regular communications between registered entities.
Page 16 of 17
Application Guidelines
Version History
Version
Date
Action
Change Tracking
1
August 26,
2008
Adopted by the NERC Board of
Trustees.
1a
November 5,
2009
NERC Board Adopted
Interpretation of R2 and R8
2
February 6,
2014
Adopted by the NERC Board of
Trustees.
Interpretation (Project
2009‐15)
Consolidation of MOD‐
001‐1a, MOD‐004‐1,
MOD‐008‐1, MOD‐
028‐1, MOD‐029‐1a,
and MOD‐030‐2.
Page 17 of 17
File Type | application/octet-stream |
File Title | NERC |
File Modified | 0000-00-00 |
File Created | 0000-00-00 |