6/4/2014
Stakeholder
Comments
DRAFT
Enhanced Curtailment Calculator (ECC)
Functional Requirements
By
Peak Reliability
With support from the ECC Advisory Committee
MMM DD, YYY
ECC Tool Functional Definition
Table of Contents
1 Introduction ................................................................................................................ 3
1.1 What this Document Defines ............................................................................... 4
1.2 What this Document Does Not Define ................................................................. 4
2 Inputs, Processes, Outputs and Mechanisms ............................................................ 5
2.1 Data Flow ............................................................................................................ 6
2.2 Inputs .................................................................................................................. 6
2.2.1 West-Wide System Model (WSM) ............................................................ 8
2.2.2 SE (State Estimator) Savecase Data........................................................ 8
2.2.3 ECC Model ............................................................................................... 9
2.2.4 Real-Time Data ........................................................................................ 9
2.2.5 ECC Element Definitions ........................................................................ 10
2.2.6 Scheduled Flow (e-Tags) ....................................................................... 10
2.2.7 Look-Ahead Data Inputs ......................................................................... 10
2.3 Processes ......................................................................................................... 11
2.3.1 Element Management Process .............................................................. 11
2.3.2 Calculate Shift Factors ........................................................................... 14
2.3.3 Calculate Element Impacts ..................................................................... 16
2.4 Outputs & Mechanisms ..................................................................................... 18
2.4.1 Visualization of Operational Results ....................................................... 19
2.4.2 User Interface and Displays ................................................................... 20
2.4.3 ECC Alarm Processing ........................................................................... 23
2.4.4 Logging and Reporting ........................................................................... 23
3 External Access, Controls, and Administration ........................................................ 24
3.1 Import, Export and API ...................................................................................... 24
3.2 Security ............................................................................................................. 24
3.2.1 User Roles, Rights, and Access ............................................................. 24
3.3 ECC Administration ........................................................................................... 25
3.4 Controls ............................................................................................................. 25
4 Performance Metrics ................................................................................................ 26
4.1 Performance...................................................................................................... 26
4.2 Availability ......................................................................................................... 26
4.3 Data Retention .................................................................................................. 27
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ECC Tool Functional Definition
Appendix A:
Terms, Acronyms, and Definitions.......................................................... 28
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ECC Tool Functional Definition
1
Introduction
This document was developed by Peak RC in consultation with the WECC ECC Advisory Committee to
define minimum functional requirements for the Enhanced Curtailment Calculator tool.
The primary tool for unscheduled flow mitigation in the Western Interconnection currently available to
Peak Reliability Coordinator (RC) is WebSAS, which is used to calculate off-path scheduled tag
curtailment responsibilities for Qualified Transfer Paths only. There are currently six Transmission Paths
that have satisfied the qualification criteria described in the WECC Unscheduled Flow Mitigation Plan.
Part of the reasoning for this qualification process is to use Qualified Controllable Devices to alter actual
flows and minimize the impact of Unscheduled Flow on the power system prior to initiating schedule
curtailments.
The RC also currently uses real time contingency analysis (RTCA) to monitor situational awareness of
the interconnection.
Recognizing the dynamic nature of interconnected system operations and adverse impacts that
Unscheduled Flow may cause throughout the Bulk Electric System, the RC has identified the need for an
expanded [?] Interconnection-wide congestion management tool with capability to monitor actual and
forecasted flows on numerous Elements and determine contributing factors that can be mitigated to ensure
the system remains within acceptable limits
Note: In this document an “Element” or “Monitored Element” is defined as including all items listed in
the NERC definition of element in addition to the individual or grouping of facilities, lines, paths, or
flowgates as monitored by the RC. In most circumstances, this document is referring to a flowgate or a
path when the term “Element” is used, but nothing in this document should be interpreted to imply the
broader use of the word “Element” is not also acceptable.
The ECC project will be broken into two phases. Phase I will provide the necessary functionality to
improve Peak RC’s situational awareness including a three-hour look-ahead component. Phase I will
allow the RC a deeper wide area view of the system and identify contributing factors to SOL or IROL
exceedances.
Phase II will focus on the WECC Unscheduled Flow (USF) Reduction Guideline methodology for nondiscriminatory curtailment of transmission service on Qualified Paths, approved by FERC on May 16,
2014, and replacement of webSAS functionality with the ECC. . A significant WECC stakeholder
process will be undertaken to best decide how to implement the new methodology in the ECC for phase
II.
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ECC Tool Functional Definition
1.1
What this Document Defines
This document defines minimum functionality for the following Phase I objectives:

Enhance the RC awareness of real-time and look-ahead operating conditions:
o
o
Calculate impacts on up to 1,000 Elements, including contingencies if necessary, as
defined and modeled by the RC:

Real-Time occupies the current hour (h)

Look-ahead occupies the next three hours (i.e. h+1, h+2, and h+3)
The impact calculation will account for real-time updates of the transmission system data
to include existing transmission and generation outages from the West-wide System
Model (WSM) via the State Estimator solution provided to the ECC once every five
minutes

Calculation of shift factors every 15 minutes, or sooner, upon a manual execution.
Additionally, every 15 minutes four new matrices of factors are created for each hour of the lookahead time window.

Identify the sources of power flow, including tagged (static and dynamic transfers),and untagged
transactions Balancing Authority (BA) Area Control Error (ACE) contributions to flow, reserve
sharing qualifying events,.

Interface with e-Tag systems for Interchange Transactions operations. The e-Tag systems’
interface will receive Interchange Transactions.

Interface with webRegistry for entities’ definitions, source/sink points definitions, and POR/POD
definitions.
1.2
What this Document Does Not Define
This document does not define the following aspects of the ECC solution and instead, relies on the vendor
to propose and define:

System design constructs including architectures, connectivity, back-up, fail-over, or redundancy
needs.

Detailed definition of graphic user interface (GUI) view screens or displays.

Detailed definition of data inputs and outputs (I/O).
o

Data I/O are classified at the object level but not at the Element level where attributes and
metadata are generally defined.
Phase II detailed functionality as yet undefined due to the need for vetting the recently FERC
approved curtailment methodology in the WECC stakeholder process.
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2
Inputs, Processes, Outputs and Mechanisms
The following section defines the functional requirements for the following:
1. Inputs – data objects that flow into the ECC and either consumed by operations/calculations to
produce new data objects or as a pass-through for display/reporting.
2. Processes – dimension of the system which perform a function and/or calculation on the input
data and models.
3. Outputs – data objects that flow out of the ECC for either display/reporting or downstream
application/process inputs.
4. Mechanisms – Ancillary processing outside of the core ECC functionality, consisting of
visualization of data, alarming, reporting, etc.
Figure 1 – Illustration of ECC ICOM Model
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ECC Tool Functional Definition
2.1
Data Flow
The graphic below represents the data flow and components of the phase I ECC. Several key inputs,
processes, and outputs are designated and further described by the numbers below.
2.2
Inputs
Inputs are data objects required by the ECC for performing operations, calculations, reporting, or display.
For the purpose of this specification, each of the following data elements is classified by Data Group,
Data Class Name, Description, and Source Name; these represent the anticipated data inputs for ECC.
Detailed definitions are expected to be provided by the vendor within a system design specification or
similar artifact and shall include the following detail:

ECC Use – name of calculation or operation consuming the input data.

Attributes – data Element details (e.g. PSBank, Name, TapPosition, LastChange, QualityCode).

Format – expected format of the data object (e.g. CSV, XML, Other).

Frequency – expected temporal frequency of the data object (i.e. every 5 minutes).

Trigger – what triggers the data to be an input to ECC.

Accuracy/Precision – any adjustments to the accuracy or precision from the source data.

Integration – specified integration methods for retrieving data (e.g. Web Services, Pub/Sub,
ICCP).
The ECC will be tightly integrated with the real-time hour (h) data and forecast data for the next three
hours (i.e. h+1, h+2, and h+3). To accurately determine the impacts on and contributions to power flows
on monitored Elements?, the ECC shall use the following inputs.
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Source of
Record
Data Type
Description
Coordinated
Outage System
(COS?)
Generator Scheduled
Outage Information
Forecasted and actual generator outages
and derates > 50 MW.
Coordinated
Outage System
(COS?)
Transmission
Scheduled Outage
Information
Forecasted transmission outages > 100 kV.
EIDE Database
Generator Unit or
project? Commitment
forecast
Forecasted next three hour and real-time
generator MW output, service load, and
pump storage.
EIDE Database
Load Forecast Data
Forecasted load for each BA area.
NAESB EIR
Registry or
WECC Registry
Mapping of
Mapping will require a manual process by
Source/Sink to BA and the BAs.
POR/POD to BA
OATI Tagging
System
E-Tag Data
E-Tag source/sink and/or POR/POD data,
mappings to generators and loads in the
model.
Registration
Reference Data
JOU Allocations
Fixed percentage provided by Peak RC to
determine allocation.
State Estimator
Actual Transmission
Facility Flows
Actual Transmission flows are available
through the SE solution interface.
State Estimator
DC Line Flow
MW flow over DC lines as an SE output.
State Estimator
Facility Ratings
Facility Ratings can be updated on the fly
so they need to be retrieved from the SE
solution instead of the base model WSM.
State Estimator
Path and Flowgate
Limits
Interface limits are available through the
SE solution interface.
State Estimator
Real-Time Pump
Storage
Actual pump MW is available in the SE
solution interface.
State Estimator
Real-Time Unit or
Project? actual MW
Output
Actual unit or project MW Output is
available in the SE solution interface.
State Estimator
Phase Shifter and LTC
Data – Real-Time Tap
Position
Actual phase shifter and LTC tap is
available in the SE solution interface.
State Estimator
Topology - Actual
Transmission Outages
Actual values are obtained by the State
Estimator.
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ECC Tool Functional Definition
2.2.1
Source of
Record
Data Type
Description
State Estimator
Topology - Circuit
Breaker and Switch
Statuses
List of status of all circuit breakers and
switches.
State Estimator
IROLs (the limit
value)
IROLs are dynamic and are provided in
the SE solution interface.
State Estimator
Topology
Actual values are obtained by the State
Estimator.
State Estimator
SOLs (the limit value)
SOLs are dynamic and are provided in the
SE solution interface.
State Estimator
Generator AGC
Response to Generator
Outages
State Estimator provides a list of
generators that will respond (steady-state
but not real-time) to generator outages.
WECC
Interchange Tool
Net Scheduled
Interchange (hourly)
Forecasted hourly net scheduled
interchange.
WECC
Interchange Tool
Next-Hour Dynamic
Transfers
Forecasted intra-hour coordinated transfer
of energy between BAs.
WECC
Interchange Tool
Real-Time Dynamic
Transfers
Real-Time intra-hour coordinated transfer
of energy between BAs.
West-wide
System Model
Registered Generator
Capability
Generator Pmax and Pmin available
through the WSM.
West-Wide System Model (WSM)
Peak will provide a network model every four weeks that is used as the base model for all ECC
calculations. The WSM base model will be provided in CSV format (or other as defined through system
design.) The WSM base model will include typical modeling attributes including, but not limited to:

Topology, including equipment connectivity

Line and transformer impedances

Generator maximum and minimum outputs

Transformer and phase shifter tap ranges
2.2.2
SE (State Estimator) Savecase Data
Peak runs a state estimator using the WSM with over 125,000 measurements mapped to the network
model. The ECC will read a new state estimator case provided by Peak once every five minutes. The
state estimator data provided to the ECC will either be a subset of “deltas” on the system that are to be
applied to the WSM base model, or it will be an entire case with all relevant state estimated data and
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ECC Tool Functional Definition
system topology. The actual State Estimator data set provided every five minutes to the ECC will be
determined as part of the detailed design process performed by the vendor.
Real-time data provided to the ECC from the Peak state estimator every five minutes includes:

Actual circuit breaker and switch status

Generator and pump output (MW)

Individual load (MW)

Phase shifter tap position

LTC tap position

DC line flows

Transmission line and transformer MW flow

Interface MW flow

Transmission line and transformer limits

Interface MW limit
2.2.3
ECC Model
The ECC will receive the base WSM monthly, or upon update by Peak Reliability. The base WSM
model will be updated every five minutes to reflect state estimator calculated system conditions. The
ECC starting conditions are the WSM base model with all necessary five minute state estimated data
applied. The ECC starting conditions are used as a primary input into the various shift factor calculations,
including subsequent calculations for data such as weighted shift factors.
2.2.4
Real-Time Data
Peak will provide real-time data, primarily from Peak’s SCADA application, to the ECC where the data is
not available in the state estimator solution. Add e-tags, state estimator data?
Dynamic Transfers are the primary data type that must be provided to the ECC directly from Peak’s
SCADA. The ECC will handle Dynamic Transfers to give maximum situational awareness of Dynamic
Transfer impacts on ECC elements. Specific requirements for Dynamic Transfers include:

The ECC will rely upon estimated Dynamic Transfer information from eTags to forecast
anticipated use in future three hours.

The ECC will utilize real-time telemetry on Dynamic Transfer tags that is provided to the ECC
via the State Estimator data or other available telemetered sources.

The ECC will utilize and combine all Dynamic Transfer tag? by each distinct
Source/Sink/POR/POD combination for forecasts?.

Actual flows (from telemetered sources) for Dynamic Transfer tags will be provided to ECC
aggregated by each distinct Source/Sink/POR/POD combination
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ECC Tool Functional Definition

Dynamic Transfers tags, will specify transmission priorities from associated e-Tags in the
WECC Interchange Tool or other non e-Tag sources [??] and will be used by the ECC to identify
curtailment priority that can be determined during detailed design with the vendor in Phase II?.

the ECC will utilize Transmission Allocation information from Dynamic Transfer eTags to
determine the maximum amount of dynamic transfer that may occur at any given moment and
energy profile information to determine actual Dynamic Transfer visualization and contribution
to power flows on a particular element?.
Unscheduled flow can have major impact to the transmission system. The ECC should be aware of
current operating hour unscheduled flow and shall make that information available through visualization
of the flows on a particular Element. The specific real-time inputs for identifying unscheduled flow in the
ECC include:

ACE – near real-time ACE values from SCADA will be made available to the ECC at least once
every five minutes. The ACE impacts on the defined ECC elements are updated upon receipt of a
new ACE value. The process for passing along the near real-time ACE values are to be
determined in the detailed design phase of the project.

RSG – Reserve Sharing Group activations are to be made available to the ECC upon activation of
an RSG event. RSG information necessary for calculating impacts will be provided to the ECC,
such as:

2.2.5
o
Generators that are responding to the RSG event
o
Generator MW output change due to the RSG event
Native Load/Network Integration Load Serving – Intra BA[?] Native load/Network Integration
Load served is derived by the ECC through the use of other inputs to the ECC, and will be
calculated based on deductions from those inputs[?] such as the tagged flows, actual load, and
actual generation, losses, reserves etc. This value is not explicitly provided to the ECC from an
external source.
ECC Element Definitions
The ECC will have the capability to model any element of the WSM for monitoring WECC-wide
situational awareness and Element SOL exceedances. An element may be a WECC Path, a transmission
line, a group of transmission lines, or a transformer. The individual facilities that make up an element
must exist in the WSM to be defined for use in the ECC. The process around managing elements in the
ECC is defined in a later section of this functional specification.
2.2.6
Scheduled Flow (e-Tags)
The ECC will read e-Tags (static and dynamic transfers) for the operating hour, as well as for the future
hours 1-3. The e-Tags will provide the details about all tagged uses of the system and will be used as a
primary input into the impact calculations.
2.2.7
Look-Ahead Data Inputs
The ECC shall utilize the following data inputs associated with the look-ahead functionality for the next
three hours (i.e. h+1, h+2, and h+3).
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
COS Outages and Returns to service - Planned transmission and generation outages for hours
one, two and three will be provided in CSV, or other format as defined through system design, as
an input to the ECC. Transmission and generation facilities that are returning to service within
the next four hours (real-time, and hours one, two and three?) are also provided to the ECC.

Load Forecast - area load forecast for hours one, two and three will be provided to the ECC. The
load forecast data will be provided as an error corrected forecast to the ECC. The ECC will not
do any smoothing or correcting of the load forecast values.

Generation Forecast - Forecasted generation output for hours one, two and three will be provided
to the ECC. The generation forecast is provided for every generating unit that is defined within
the WSM. The forecast may be provided as an aggregate plant level forecast if the individual unit
granularity does not exist. The ECC will not have to do any smoothing or correcting of the
generation forecast values, as this function will be performed outside the ECC.

NSI Forecast – Net area interchange is to be provided as an input to the ECC from the Western
Interchange Tool (WIT). An external application will pull the data from WIT and perform data
validation and correction to ensure accuracy and usability of the data. The NSI data will then be
provided back to the ECC for use as an input to various ECC calculations. The ECC will not
have to do any smoothing or correcting of the NSI values, as this function will be performed
outside the ECC.

WECC Pre-schedule/Delivery day e-tags?
2.3
Data Transfer, Calculation other Processes
Processes within the ECC are mechanisms used to transfer data, perform calculations, and other
automated or manual actions.
2.3.1
Element Management Process
The elements of the ECC are the core facilities, or collection of facilities, that are defined for monitoring
in the ECC. There are many processes that are defined to capture the proper definition, and management
of the elements within the ECC.
Use Cases define user interactions at a functional level. It is not the intention of this document to
necessarily define how the use case or workflow is to be implemented. For this document, the use cases
and workflows themselves are defined with minimum functionality expected to be met by the tool.
The following use cases shall be implemented in the ECC:
1. Create an Element
2. Modify an Element
3. Deactivate an Element
4. Delete an Element
5. Auditing the Creation of an Element
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2.3.1.1 Creating an Element
This use case represents an authorized user’s ability to create an Element. Minimum functionality to
support this use case shall include:

The RC role is the only role authorized to create an Element.

Elements shall be selected based on the WSM modeled equipment.

Elements must exist in the WSM.

The information entered during creation of an Element shall be recorded in an audit log including
all entry fields as well as the user information.
2.3.1.2 Modify an Element
This use case represents an authorized user’s ability to modify an Element. Minimum functionality to
support this use case shall include:

The RC role is the only role authorized to modify an Element.

The information entered during modification of an Element shall be recorded in an audit log
including all entry fields as well as the user information.

For the purpose of this document, reactivating an Element from a deactivated state shall
constitute a modification.
2.3.1.3 Deactivate an Element
This use case represents an authorized user’s ability to deactivate an Element. Minimum functionality to
support this use case shall include:

The RC role is the only role authorized to deactivate an Element.

For the purpose of this document, deactivation shall mean ‘soft-deletion’ (i.e. remove the Element
from the ECC’s operational functionality).

Deactivation will notify the creator of the Element through an auditable mechanism that the
Element has been deactivated.

The information entered during deactivation of an Element shall be recorded in an audit log
including all entry fields as well as the user information.

An Element will be marked as deactivated and will not be hard-deleted or permanently deleted
from the system as per §Error! Reference source not found..
2.3.1.4 Delete an Element
This use case defines functional rules for deleting an Element. The ECC shall prohibit a unilateral
deletion function of any Element in order to allow thorough traceability via the audit use case. Deletion of
an Element is to be restrictive and subject to formal authorization. The following functional requirements
support this construct:

Under normal operation, an Element shall be marked as deactivated and will not be hard-deleted
or permanently deleted.
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
The vendor shall supply an appropriate administrative hard-deletion or permanent-deletion
mechanism for the administrative role while ensuring appropriate system and database integrity.

An Element may be deleted only via administration-level credentials.

An Element may only be deleted with approval from Peak RC

Vendor shall archive any historical ECC action (e.g. alarms, curtailment action, modification,
etc.) on the deleted Element.
2.3.1.5 Approving an Element
This use case represents an authorized user’s ability to approve a newly created Element, modified
Element, or deactivated Element. Functionality requires the ECC to enforce a workflow whereby an
authorized user performing the aforementioned activities (§Error! Reference source not found., Error!
Reference source not found., Error! Reference source not found.) shall only be committed upon
successful approval by a user authorized to perform the approval. Minimum functionality to support this
use case shall include:

For the purpose of this document, approval shall mean both technical and business process:
o
Technical approval: the ECC shall perform basic validation on user-entry data fields to
the extent of ECC operational logic.
o
Business process approval: RC is responsible for developing business practices
associated with the approval use case.

The RC or designated entity shall approve the created/modified/deactivated Element.

The approval screen shall at least have the following fields:
o
Date/Time fields associated with create/modify/deactivate actions
o
RC User ID for create/modify/deactivate actions
o
Data fields for create/modify/deactivate actions
o
RC User ID for approve actions
o
Comments
o
Effective date/time of the Element once RC approves

The RC approval process of an Element shall be recorded for audit purposes.

RC will notify TOP if Elements within TOPs jurisdiction are created/modified/deactivated in
ECC.
2.3.1.6 Auditing the Creation of an Element
This use case represents an authorized user’s ability to audit data and actions associated with the creation
of an Element. Functionality may include ad hoc querying or reporting. Minimum functionality to support
this use case shall include:

Audit user actions and data entry for created elements.

Audit approver actions and data entry for created elements.
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ECC Tool Functional Definition

Audit historical alarms and modifications associated with an Element over a user-entered
timespan.

Include all date and time stamps for actions or entries.

Include all users ID’s associated with actions or entries.

Via appropriate display(s), audited data fields shall show original state and changed state where
applicable.
2.3.2
Calculate Shift Factors
Shift factors are the most basic calculation performed within the ECC. There are a variety of shift factors
calculated, some describing the impact on elements from a single generator, others describing the impact
on elements from a group of generating resources.

Shift factors will be calculated every 15 minutes for a rolling window from T0 through hour
ending T0+3.

Shift factors will be calculated for 15 minute intervals for the current operating hour, followed by
hourly intervals for hours T1 – T3.
A near real-time state estimator solution case is provided to the ECC every 5 minutes, yet the shift factors
are only calculated every 15 minutes. The primary use for the state estimator solution when no shift
factor updates are occurring is in the impact calculation process.
The ECC shall calculate the following types of shift factors:
2.3.2.1 Power Transfer and Outage Transfer Distribution Factors

Power Transfer Distribution Factor (PTDF) Elements are elements that do not consider
contingencies during curtailment evaluation. With PTDF Elements the monitored branches alone
are considered during curtailment evaluation.

Outage Transfer Distribution Factor (OTDF) Elements are Elements that take into account a
predefined contingency during curtailment evaluation. With OTDF Elements the monitored
branches are considered with a specific facility removed from service during curtailment
evaluation.

An Element can exist as a PTDF Element or an OTDF Element.

An Element defaults to a PTDF Element unless OTDF branch data is specified in the Element
creation process.
2.3.2.2 Generation Shift Factors

A Generation Shift Factor (GSF) between any two generators is the difference between the
generators’ GSF to the swing bus.

The principles of superposition shall apply when calculating GSFs.

GSFs are used in Transmission Distribution Factor (TDF) calculations and Generation-to-Load
Distribution Factor (GLDF) calculations.
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ECC Tool Functional Definition

GSFs on the Element GSF display in the ECC shall indicate which generators contribute to or
relieve congestion on a selected Element.

Example: If a generator indicates a GSF of 15.2% on Element X, this means that 15.2% of the
generator’s output flows on Element X provided the injection is withdrawn at the swing bus.
2.3.2.3 Transmission Distribution Factors

A Transmission Distribution Factor (TDF) represents the impact of an Interchange Transaction on
a given Element and determines which are eligible for curtailment in the ECC.
o
Only those Interchange Transactions with a TDF of n% or greater, as determined by RC
approved standard/practice/policy, are subject to Curtailments.
o
Example: If a tag indicates a TDF of 8.3% on Element X, this means that 8.3% of the
transfer amount on that tag flows on Element X.

TDFs address the question, “What portion of a power transfer shows up on Element X?”

ECC calculations shall use Point of Receipt (POR) and Point of Delivery (POD) for
determination of TDFs.

ECC shall integrate with the NAESB EIR Registry or WECC Registry and obtain the most
current POR/POD information for TDF calculations. This will require some manual mapping on
the model data to establish the needed granularity:
o
Source/Sink to BA
o
POR/POD to BA

ECC shall calculate the real-time TDFs on monitored elements based upon the model
incorporated into the tool and the points mapped to the model.

ECC must use real-time system topology and data, including actual generation and outages, when
calculating TDFs and mitigation responsibilities.

ECC must be able to create a matrix to show all POR/POD combinations in order to accurately
model and determine TDF of monitored elements:

o
Mapping of Source/Generators to POR/POD.
o
Mapping Source/Generator to a Regional Zone/sub- zone/BA (or by company/area as per
State Estimator).
TDFs shall be calculated as the weighted sum of the GSFs of the generators that comprise the
BA, Zone or sub-zone, or any aggregate of generators, where the weighting factors are predetermined based on individual generator’s capacity (or some other criteria as to be decided) or
determined in real-time, based on individual generator outputs. TDFs are calculated as follows:
𝑇𝐷𝐹𝐵𝐴 = [∑(𝐺𝑆𝐹𝐺𝑒𝑛𝑒𝑟𝑎𝑡𝑜𝑟(𝐵𝐴) ∗ 𝑊𝐺𝑒𝑛𝑒𝑟𝑎𝑡𝑜𝑟(𝐵𝐴) )] / ∑ 𝑊𝐺𝑒𝑛𝑒𝑟𝑎𝑡𝑜𝑟(𝐵𝐴)
Where:
TDFBA is the TDF of a Balancing Authority
GSFGenerator(BA) is the GSF of a generator in a Balancing Authority
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ECC Tool Functional Definition
WGenerator(BA) is the weighting factor of a generator in a Balancing Authority
2.3.2.4 Load Shift Factors

Load Shift factors (LSF) are used to calculate GLDFs, which are used to determine Generationto-Load (GTL) obligations (i.e. the LSF is a component of the GLDF.

LSFs shall be shown along with GSFs on the GLDF displays in the ECC.

Similar to TDFs, LSFs are calculated as the weighted sum of individual loads distribution factor,
for all loads belonging to a BA or zone.
2.3.2.5 Generation-to-Load Distribution Factors
The Generation-to-Load (GTL) process allows for non-firm and firm of Network Integration (NI) and
Native Load (NL) services to be treated comparably with non-firm and firm Point-to-Point (PTP)
Transactions during transmission service evaluations. The ECC assists the RC in allocating appropriate
relief of all PTP transactions and GTL impacts in order to ensure comparable curtailment.

A Generation-to-Load Distribution Factor (GLDF) is the difference between a GSF and an LSF
and determines the total impact of a generator serving its native BA load on an identified
transmission facility or monitored Element.

GLDFs shall be used to determine the GTL of BAs where generators in the BA serve the native
and network integration load of the BA.

The GTL calculation shall form the basis for determining a BA relief obligation when curtailment
is needed.

Only those generators with a GLDF of n% or greater, as determined by the RC approved
standard/practice/policy, are used in calculating the GTL relief obligation.

GLDFs shall be shown in the Element GLDF display and the CA GLDF display in the ECC.
o
In the Element GLDF display the user selects an Element and is shown a list of
generators that contribute to flow as a byproduct of serving their own BA area load (i.e.,
the GTL impact).
o
In the CA GLDF display, the user shall be shown a listing of Elements that are impacted
by generators serving their own BA area load. From this list, the user can drill down and
view the generator contribution to flow.
2.3.2.6 BA/Zonal Shift Factors

BA/Zonal Shift Factors (ZSF) represents the shift factors of a subset of generators of a BA or a
Zone.

ZSFs are calculated in the same manner as TDFs.
2.3.3
Calculate Element Impacts
Impact calculations determine the amount (relative or absolute) of impact a transaction between
source/sink or POR/POD that flows on transmission elements. The term transaction is used quite loosely.
A transaction may represent an interchange between two Balancing Authorities (also known as inter-BA
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ECC Tool Functional Definition
transaction), or a generator serving a load within a balancing area, also known as intra-BA transaction.
Transactions may or may not be tagged, and many times represent generation from a source point
comprised of multiple generators supplying the load of a region or zone, comprised of multiple individual
loads.
Relative impact is determined by the Shift Factors alone and represents the percentage of transaction
between two points that flow on a transmission element. Absolute impact takes into account the actual
transaction amounts, and is calculated by multiplying the relative impact of the transaction by the
transaction MW amount.
Element impacts are calculated once every five minutes using the latest state estimator solution. The
impact calculations will make use of the most recent shift factors calculated by the ECC.
There are two types of impact calculations that ECC will perform. The first identifies the contribution of
transactions to the flow on transmission elements. The, second identifies the impact of curtailing
transactions on the flow of transmission elements. The former provides situational awareness, while the
latter can be used in transmission loading relief calculations, such as the Unscheduled Flow Mitigation
procedure. The differences between Situational Awareness Impact Calculations and Curtailment Impact
Calculations are better explained through an example:
Suppose a system consisting of two Balancing Areas with generation and load, a transaction between the
BAs, a monitored transmission element, and TDFs and LSFs to the swing bus as shown in the figure
below.
Figure 2 – Example System for Impact Calculations
The transactions are:

Generation-to-Load (or Intra-BA transactions)
o
MWGA-LA → GA provides 100 MW to LA
o
MWGB-LB → GB provides 50 MW to LB
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ECC Tool Functional Definition

Interchange Transaction (or Inter-BA transaction)
o
MWGA-LB → GA provides 50 MW to LB
A Situational Awareness impact calculation will indicate that the flow contributions from each transaction
on the monitored transmission element as:
FlowGA-LA = (TDFA – LSFA) × MWGA-LA = (0.70 – 0.65) × 100 = 5 MW
FlowGB-LB = (TDFB – LSFB) × MWGB-LB = (0.60 – 0.55) × 50 = 2.5 MW
FlowGA-LB = (TDFA – LSFB) × MWGA-LB = (0.70 – 0.55) × 50 = 7.5 MW
Situational Awareness Flow = 5 MW + 2.5 MW + 7.5 MW = 15 MW
If the monitored element is congested and the transaction between GA and LB is curtailed, the Curtailment
impact will not reduce the flow by 7.5 MW, which is the impact of the Interchange Transaction. Instead,
since load is not curtailed, load LB will be supplied by an increase generation in GB. This impact is
calculated as:

Reduce generation in GA by 50 MW: ΔFlowGA-LB = (0.70 – 0.55) × (–50) = – 7.5 MW

Increase generation in GB by 50MW: ΔFlowGB-LB = (0.60 – 0.55) × (+50) = + 2.5 MW

ΔFlow = [(TDFB – LSFB) – (TDFA – LSFB)] × MWGA-LB =
= (TDFB – TDFA) × MWGA-LB = (0.60 – 0.70) × 50 = – 5.0 MW
The curtailment of the Interchange Transaction yields a reduction of 5.0 MW on the flow of the
monitored transmission element.
2.3.3.1 Calculate Forecasts
The ECC will calculate a “raw” expected flow on an element based on all of the component inputs known
to the ECC, both tagged and untagged uses of the system. Recognizing that the data is imperfect and that
other system impacts are outside of Peak’s control, there is a need to have an error calculation engine that
“corrects” the raw expected element flows. The process “Calculate Forecasts” simply updates the
element forecast flow to be the sum of the raw determined element flow and an error correction MW
value.
The ECC detailed design spec will define all of the requirements for the error correction and forecast
calculation processes. It is possible, as indicated by the diagram, that these components reside outside of
the ECC. However, that final decision will not be made until the ECC detailed design spec is complete.
2.4
Outputs & Mechanisms
Outputs are data objects (i.e. ECC Factors) produced by the ECC as a result of performing operations or
calculations. Only data created by the ECC is considered an output; pass-through data, which may be
specified as an Input for ECC display or reporting but not created by ECC, is not defined as an Output.
For the purpose of this specification, each of the following data elements is classified by Data Group,
Data Class Name, and Description.
Detailed definitions are expected to be provided by the vendor within a system design specification or
similar artifact and shall, at a minimum, include the following detail:
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ECC Tool Functional Definition

ECC Module – name of calculation or operation which creates the data.

Attributes – data Element details (e.g. PSBank, Name, TapPosition, LastChange, QualityCode).

Format – if applicable, expected format of the data object (e.g. CSV, XML, Telemetry).

Data Dictionary – if applicable, the database view, stored procedure, table, or query where the
data may be obtained.

Frequency – expected temporal frequency of the data object (e.g. 15 minutes).

Trigger – what triggers the data to be an output from ECC.

Accuracy/Precision – defined accuracy and/or precision of the data object.

Integration – specified integration methods for retrieving data (e.g. Web Services, Pub/Sub, and
ICCP).
Mechanisms specify functionality of the system for user and external application access. The following
types of mechanisms are defined:

Visualization of Operational Results

User Interface and Displays

Alarm Processing

Reporting

Import, Export and API
2.4.1
Visualization of Operational Results
The ECC must provide output to the RC System Operators (RCSO) that is meaningful for the situational
awareness of (?) operations of the Peak RC area. Specific requirements for ECC output and enhanced
situational awareness of real-time information include:
 Visualization of real-time flows on all elements and the corresponding limit
 Visualization of the composition of flows on an Element:
o Visualization of Dynamic Transfers (Dynamic Schedules and Pseudo-Ties, including
NERC tag priorities) and percent of total MW flow contribution (?)
o Tagged flow MW (including NERC tag priorities) and percent of total MW flow
contribution.
o Native load and intra-BA Network Integration Load service or market flow MW percent
and total MW flow contribution.
o ACE, listed by BA, including percent MW and total MW flow contribution.
o Reserve activation MW percent and total MW flow contribution.
o Losses?
 Summary of individual tags and other composition of flows (?) to a particular Element that are
sorted by TDF.
 For look-ahead (i.e. h+1, h+2, and h+3), visualization of expected flows on elements and the
corresponding limit.
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ECC Tool Functional Definition
This situational awareness information must be presented in a rolled up fashion to provide a summary or
overview of all elements defined within the ECC. Capability will exist to allow for the RCSO to drill
down in to the details of each defined Element.
2.4.2
User Interface and Displays
This document does not detail the nuances of the ECC displays so as not to constrain the vendor’s
solution design. The vendor shall recommend(?) what displays will be implemented, including proposed
screenshots where applicable. Peak RC shall approve the specification.
Display Type
Description
Impact Trend
This display provides a summary, per transmission priority, of tagged and untagged
use for the selected time period in the ECC.
Transaction List
This display provides a summary of the energy transactions in the ECC for a
specified time range.
Intra-hour Transaction
List
This display provides a summary of the intra-hour schedules for the current and next
hours.
Next Hour Transaction
List
This display provides a summary of the next hour transaction schedule changes
(increasing or decreasing).
Whole Transaction List
This display provides a summary of the transaction impacts on a selected element. It
provides a view of possible curtailment actions.
Current/Next Hour
Whole Transaction List
This display provides a summary of the transaction current and next hour impacts on
a selected element. It provides a view of possible curtailment actions.
Net Interchange
This display provides a summary of the export, import and net MWs of an RC and
BA.
Element TDF
This display provides the TDF on a user specified element for hypothetical
transactions between selected source and/or sink BAs. This display also provides the
entry point for viewing LODFs (Line Outage Distribution Factors).
Element LODF
This display provides the LODFs (Line Outage Distribution Factors) on a user
specified element. The LODFs represent the effect of branch outages on the element
flow on LODF elements defined.
Source/Sink TDF
This display provides element TDFs for hypothetical transactions between selected
source and/or sink BAs.
Source/Sink Availability
[Place holder]
Element GSF
[Place holder]
Element GLDF
This display provides the Generation-to-Load distribution factors (GLDF) on a user
specified element for a given BA. The GLDF is the impact on the element for a
generator in a given BA to provide the native load or network integration load of the
same control area. Only the generators with a GLDF impact greater than 5% and the
next-hour matrix are shown on this display.
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ECC Tool Functional Definition
CA GLDF
This display provides the user with a list of elements that are impacted by 5% or
more by the control area GLDF.
Generator GLDF
This display provides the Generation-to-Load Distribution Factors (GLDF) from a
user specified generator to a user specified Service Point (SP), or to a list of all
service points. The GLDFs give the impact on all elements for the generator serving
load within the service point area. Only the generators with a GLDF impact greater
than the user entered GLDF Cutoff % and the next-hour matrix are shown on this
display.
The Generator GLDF on an element for the load at the service point is calculated as
the GSF (Generation shift factor) minus the LSF (Load Shift Factor) for that
flowgate. The Service Point (SP) defines the area used to calculate the LSF. This
may be a BA, a marginal zone or a specific bus, depending on the level of
granularity at which the SP is defined and which SP is selected.
Generator Inc/Dec GSF
This display provides the Generation Shift Factors (GSF) for a user specified pair of
Incrementing & Decrementing generators. The GSFs give the impacts on a list of
elements for the pair of generators specified.
The Generator GSF on an element is calculated as the GSF of the INC Generator
minus the GSF of the DEC Generator for that flowgate. Only elements with
resulting GSFs impacts at or greater than the user entered GSF Cutoff % are shown
on this display.
The following minimum requirements, however, are defined as general requirements for the user interface
(UI):

UI shall be based on open standards and/or common UI programming language.

Displays shall have the appearance of a normally accepted web based or thick-client graphical
user interface (GUI).

The UI shall be capable of presenting multiple and configurable views (e.g. tabular data views,
configurable graphs) to present the data as applicable to the display’s purpose.

Displays shall be consistent with a common look and feel.

Displays shall have the capability of accessing and displaying data from various sources and
applications.

The user interface shall be independent of applications and databases.

Displays shall be accessible via toolbar buttons, regular display buttons or hot links. The user
interface shall provide the following features:
o
Tabular displays that support paging, sorting, and data filtering.
o
On-screen data entry validation.
o
Program and functional execution from within the displays.
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ECC Tool Functional Definition
o
Displays shall be protected by security features including login/logoff and configurable
screen obfuscation after a configurable time period of inactivity. This feature shall be
independent of any screen-saver option native to the operating system of the workstation.
o
As defined in §Error! Reference source not found., access to data and displays
controlled by user access/authorization rights.
o
Configurable menu functions.
o
Capability to enable Side-by-Side displays.
o
Dates/calendar functions.
o
Configure displays to hide/unhide columns or display items
o
Shall permit multiple windows to be viewed concurrently on the same monitor.
o
The windows shall be displayable in either overlapping or tiled.
o
All displays and screens shall be functionally capable of supporting multiple monitor
configurations, extended or mirrored, from a single workstation.

Consistent user interface procedures shall be provided to initiate application execution, insert
data, annunciate errors, and display and report results from application programs.

Displaying and Rendering Data shall consider:
o
Analysis-type displays shall be similar to those of the IDC.
o
Appropriate displays to query all registered elements and allowing filtering capabilities
based on the information contained in Element displays.
o
Calculate flow impacts by different uses of the system and mitigation responsibilities for
Qualified Transfer Paths or any defined Element with an associated limit.
o
The toolset must display, alarm and notify the RC once flow is exceeding the defined
threshold for an Element.
o
A list of each Element that has an active mitigation decision should be displayed for the
current operating hour and for the next 3 hours.
o
ECC shall have the ability for users to enter a query in order to determine impacts. The
query must allow for the user to select from a list of attributes including Source, Sink,
Regional zone/Sub-zone, POR/POD, and monitored Element and a result set that can be
sorted should be provided with information regarding the impacted zones, POR/POD,
and monitored elements with TDF values.
Voice of Customer – The following displays and screens represent stakeholder (RCs and BA/TOPs)
input and preferences. Where technically feasible, vendor should consider the following:

Main Screen or Display – consisting of the following Menus:
1. Registry (BA, TOP, PSE, POR/POD, Source/Sink)
2. Model (Transfer Distribution Factors, Generator Shift Factors, Qualified Paths, Competing
Paths, Qualified Path Operators, Zones, Phase Shifters)
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ECC Tool Functional Definition
3. Flow-based Study (Flow-based Study Paths, Mapping Study Path, Transfer Distribution
Factors, Transaction Contribution, Generation Shift Factors)
4. Mapping (Qualified Paths, Source/Sink(zones), BA(default Zone), Registry BA(Model BA),
DC Line Source/Sink(POR/POD), PST (BA Source/Sink), PST (POR/POD)
5. USF (Summary, Issue, Study)
6. Tools (Transactions, Transaction Contribution)
7. Logs
8. Misc. (Documentation, Options, Close)

Alarm Summary Screen or Display – alarm Summaries should be made available. The alarm
summary should include unacknowledged alarms only.

Alarm Log Screen or Display – alarm Logs should be made available. The alarm Log should
include all alarms, the time it was acknowledged, and the username that acknowledged the alarm.
2.4.3
ECC Alarm Processing
The system shall have the ability to configure and manage alarms such that the alarm conditions are
reported in a clear, concise, and timely manner to the operators. At a minimum, alarms shall be available
for the following conditions:

Exceedances of an Element SOL (current hour or future hour).

Failure of data transfer into or out of the ECC.
When curtailment is required to be acknowledged and approved, alarms should be easily identifiable with
the ability to set sound, color, and acknowledgment required for displayed messages. Alarm notification
should be easily transportable through email or web interfaces and leverage common standards (e.g. using
XML) to allow for monitoring outside of ECC. All alarm messages should be logged and retained for
audit and compliance purposes.
2.4.4
Logging and Reporting
The system shall have the ability to provide historical reporting on all ECC calculations and alarms.
Standard report functions shall allow the following:

Number of ECC alarms.

Alarm description.

Relief requested (MW) and achieved.

List of Tags curtailment and Generation redispatch required.
The system design shall accommodate the ability to either create custom reports (i.e. Business
Intelligence capabilities) and/or support third-party reporting tools (e.g. Crystal Reports).
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ECC Tool Functional Definition
3
External Access, Controls, and Administration
3.1
Import, Export and API
The system shall have the ability to export any data from any screen, display, or report. At a minimum,
the following export formats shall be supported:
o
Microsoft Excel File Format
o
Comma-Delimited File Format
o
Tab-Delimited File Format
o
XML File Format
Users of the system shall have the option to select formats from an export dialog.
Importing data, considering the same formats as export functionality, shall be considered by the vendor to
accommodate circumstances when integration methods for input data are inoperative.
ECC output data must be made available to external applications through an Application Programming
Interface (API). The API shall be able to access necessary information for storage and visualization in
other Peak systems.
At a minimum, the following data classes shall be available via the API:

Element MW flows and the components that contribute to the Element flow:
o
Tagged MW flow
o
MW flow as contributed by Area Control Error
o
Untagged transmission flows
o
Reserve activations
o
Losses?

Look ahead (i.e. h+1, h+2, and h+3) Element MW flows

Alarms
3.2
Security
The vendor shall define how security controls will be implemented, including any interpretation of NERC
CIP standards. Peak RC shall approve the specification.
3.2.1
User Roles, Rights, and Access
Phase I of the ECC focuses solely on improving situational awareness for Peak RC. Current WebSAS
users will continue to access the same WebSAS system as today. The user roles below are needed to
support the phase I operation of the ECC are as follows:

RC System Operators (RCSO)

RC Engineers
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ECC Tool Functional Definition
Entities with current WebSAS role credentials shall be able to see summary data available in the ECC.
Those entities shall also have access to view real-time and hours one through three (i.e. h+1, h+2, and
h+3) data associated with any of the active elements.
The ECC shall have the functionality for the administrator to designate ECC access and authorization (i.e.
screens, displays, menus, function, or data) based on individual roles and/or users.
The ECC Administrator shall have the ability to also provide individual users or roles access to ECC
situational awareness displays and data. Detailed definitions are expected to be provided to the vendor
prior to a system design specification, or similar artifact; Peak RC shall provide to the vendor roles for the
ECC. Phase II non-RC user roles, rights, and access will be determined with the other design details
necessary for that phase.
3.3
ECC Administration
ECC application shall have administrator functions available only to an administrative role. Specific
functions are contingent upon the vendor’s system design and shall consider the following functionality:

Controlling (i.e. add/modify/deactivate/delete) users and roles for localized and/or remote access.

Depending on the vendor’s solution design, the following functionality shall be limited to the
administrator role.
o
Managing elements
o
Managing reference data links and/or metadata.
o
Stop/start/reinitialize services or daemons.
o
Startup parameter configuration.
o
Network data storage locations (i.e. SAN storage or Directory Files Shares).
o
Ability to add/delete user rights and roles.
The vendor shall define how administrative controls will be implemented; Peak RC shall approve the
specification.
3.4
Controls
Controls define the processing, operation, or execution of the ECC. The defined controls specify how or
what the vendor shall consider for the design and/or architecture of the system. Controls include the
following types:
1. Security Considerations -- requirements of the system specific to access and use-authorization
of the ECC by either a user/entity or another application.
2. User Roles, Rights, and Access – defined roles of users of the ECC.
3. Use Cases– process requirements which define execution of user steps and routing of data
and/or information in sequence (e.g. review and approval).
4. Administration – requirements of the system specific to the administration of the ECC.
The ECC vendor detailed design spec must address each of the controls.
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ECC Tool Functional Definition
4
Performance Metrics
The following section defines minimum metrics for ECC use and operation.
4.1
Performance
The following performance metrics are required functionality for the ECC.

The ECC shall be able to support 15 concurrent phase I Peak RC users. However, the system
must be built to be scalable to support all webSAS users and future growth in users as the ECC is
developed.

ECC shall support the following simultaneous user types in phase I, by role without a degradation
in performance:
o
RCSO, 10
o
RC Engineer, 4
o
Applications Support (IT), 1
Future phases of the ECC project will incorporate additional user roles when webSAS functionality is
brought into the ECC (Phase II), as well as if and when congestion management curtailment and
redispatch capabilities are expanded and brought into the ECC (Phase III or later?). The system must be
scalable to ensure acceptable system performance when the additional users are introduced to the system.
ECC shall ensure that the response time from when a request or transaction is initiated by a user, to the
time an application response is returned, will be less than 3 seconds for 95% of all transactions, measured
at a Local Area Network, and not subject to external limitations, such as Internet availability and
performance. This performance requirement does not include shift factor and future curtailment
calculations.
4.2
Availability
The ECC is expected to demonstrate a minimum availability of 99.5%. This means that the system is
designed for high availability, with appropriate fail-over and redundancy designs.

ECC shall be available 24 hours a day, 7 days a week with the exception of scheduled and
unscheduled downtime.

ECC shall be reliable with respect to functionality and data integrity. ECC will go through testing
and, upon acceptance by Peak RC, it must perform according to approved specification.

ECC shall maintain unscheduled downtime per year less than or equal to 10 hours, unless
mutually agreed by vendor and Peak RC.

For unscheduled downtime, vendor shall initiate repair in less than or equal to 1 hour.

Vendor shall limit scheduled downtime per year less than or equal to 20 hours, unless mutually
agreed by vendor and Peak RC. Scheduled downtime shall not count towards expected
availability.
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ECC Tool Functional Definition

4.3
Vendor shall notify Peak RC of the ECC’s unavailability if the system becomes unavailable for
normal operations due to any reason, including both scheduled and unscheduled maintenance.
Notification shall include the following:
o
The reason for the downtime
o
When the down time will start
o
When the down time will end
o
Contact number for vendor support
Data Retention
The following requirements are specific to ECC data retention including operational data (i.e.
Inputs/Outputs) and audit data.

ECC shall support data retention of all transactions made for five years, except for extremely
large volume data, such as Shift Factors (GSF, LSF, TDF, etc.). Shift Factors must be retained
for a minimum of 30 days.

Input data for ECC operations shall be retained 24 hours in a rolling data store.
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ECC Tool Functional Definition
Appendix A:
Terms, Acronyms, and Definitions
The following terms and acronyms are used is this document.
Term
Definition
ACE
Area Control Error
BA
Balancing Authority
BES
Bulk Electric System
CA
Control Area
CIP
Critical Infrastructure Protection
COS
Coordinated Outage System. Coordinated Outage Scheduling System is the Transmission
and Generation outage scheduling system used by Peak to collect and manage scheduled
outages for the Peak RC area.
CSV
Comma Separated Values
DC
Direct Current
Dynamic
Schedule
A time-varying energy transfer that is updated in Real-time and included in the Scheduled
Net Interchange (NIS) term in the same manner as an Interchange Schedule in the
affected Balancing Authorities’ control ACE equations (or alternate control processes).
(Definition approved by NERC BOT but not FERC.)
Dynamic
Transfer
The provision of the real-time monitoring, telemetering, computer software, hardware,
communications, engineering, energy accounting (including inadvertent interchange), and
administration required to electronically move all or a portion of the real energy services
associated with a generator or load out of one Balancing Authority Area into another.
ECC
Enhanced Curtailment Calculator
EIDE
Electric Industry Data Exchange. Electric Industry Data Exchange is an XML
communications protocol utilized by WECC entities, including Peak RC.
EIR
Electric Industry Registry
Element
Any electrical device with terminals that may be connected to other electrical devices
such as a generator, transformer, circuit breaker, bus section, or transmission line. An
Element may be comprised of one or more components.
FDS
Functional Design Specification
GLDF
Generation-to-Load Distribution Factors
GSF
Generation Shift Factors
GTL
Generation to Load
GUI
Graphical User Interface
I/O
Inputs and Outputs
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ECC Tool Functional Definition
Term
Definition
ICCP
Inter-Control Center Communications Protocol
ICOM
Inputs, Controls, Outputs, and Mechanisms
IROL
Interconnection Reliability Operating Limit
LODF
Line Outage Distribution Factors
LSF
Load Shift Factors
MW
Megawatt
NAESB
North American Energy Standards Board
NERC
North American Electric Reliability Corporation
NI
Network Integration
NL
Native Load
NSI
Net Scheduled Interchange
OATT
Open Access Transmission Tariff
OTDF
Outage Transfer Distribution Factors
POD
Point of Delivery
POR
Point of Receipt
PSE
Purchasing-Selling Entity
Pseudo-Tie
A time-varying energy transfer that is updated in Real-time and included in the Actual
Net Interchange term (NIA) in the same manner as a Tie Line in the affected Balancing
Authorities’ control ACE equations (or alternate control processes). (Definition approved
by NERC BOT but not FERC.)
PST
Phase-Shifting Transformer
PTDF
Power Transfer Distribution Factors
PTP
Point-to-Point
Pub/Sub
Publish and Subscribe
RC
Reliability Coordinator
RSG
Reserve Sharing Group
SAN
Storage area network
SE
State Estimator. State Estimator is a real-time application used by Peak Reliability to
determine the “state” of the Western Interconnection. The SE solution results includes
system topology, generator outputs, line/transformer flows, load values, transformer and
phase shifter tap positions, etc.
SOL
System Operating Limits
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ECC Tool Functional Definition
Term
Definition
TDF
Transmission Distribution Factors
TLR
Transmission Load Relief
TOP
Transmission Operator
TP
Transmission Planner
TRM
Transmission Reliability Margin
TSP
Transmission Service Provider
UFM
Unscheduled Flow Mitigation
UFR
Unscheduled Flow Reduction
UI
User Interface
USF
Unscheduled Flow Relief
WECC
Western Electricity Coordinating Council
WIT
WECC Interchange Tool. The Western Interchange Tool is a system to facilitate and
coordinate interchange between WECC Balancing Authorities (BAs). The WIT will also
provide Interchange scheduling information to Peak RC.
WSM
West Wide System Model. West-wide System Model is the base model that is created
once every 4-6 weeks by Peak RC. The WSM does not contain real-time information;
rather it contains the basic system connectivity, equipment attributes, and other general
power system modelling information.
XML
Extensible Markup Language
ZSF
Zonal Shift Factor
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