ECC Tool Functional Definition

DRAFT

Version 12

Enhanced Curtailment Calculator (ECC)

Functional Requirements

By

Peak Reliability

With support from the ECC Task Force

MMM DD, YYY

ECC Tool Functional Definition

Table of Contents

1Introduction

1.1Phase I versus Phase II

1.2What this Document Defines

1.3What this Document Does Not Define

2Inputs, Processes, Outputs and Mechanisms

2.1Data Flow

2.2Inputs

2.2.1West-Wide System Model (WSM)

2.2.2State Estimator Savecase Data

2.2.3ECC Model

2.2.4ECC Element Definitions

2.2.5Mapping WSM to ECC

2.2.6Real-Time Data

2.2.7Scheduled Flow (e-Tags)

2.2.8Look-Ahead Data Inputs

2.3ECC Element and Calculations Processes

2.3.1Element Management Process

2.3.2Calculate Shift and Distribution Factors

2.3.3Calculate Element Impacts

2.4Outputs & Mechanisms

2.4.1Visualization of Operational Results

2.4.2User Interface and Displays

2.4.3ECC Alarm Processing

2.4.4Logging and Reporting

3External Access, Controls, and Administration

3.1Import, Export and API

3.2Security

3.3User Roles, Rights, and Access

3.4Non-RC User Access

3.5ECC Administration

3.6Controls

3.7Documentation

4Performance Metrics

4.1Performance

4.2Availability

4.3Data Retention

Appendix A:...... Terms, Acronyms, and Definitions

1Introduction...... 3

1.1Phase I versus Phase II...... 4

1.2What this Document Defines...... 4

1.3What this Document Does Not Define...... 4

2Inputs, Processes, Outputs and Mechanisms...... 6

2.1Data Flow...... 7

2.2Inputs...... 7

2.2.1West-Wide System Model (WSM)...... 9

2.2.2SE (State Estimator) Savecase Data...... 10

2.2.3ECC Model...... 10

2.2.4ECC Element Definitions...... 10

2.2.5Mapping WSM to ECC...... 10

2.2.6Real-Time Data...... 11

2.2.7Scheduled Flow (e-Tags)...... 12

2.2.8Look-Ahead Data Inputs...... 12

2.3ECC Element and Calculations Processes...... 13

2.3.1Element Management Process...... 13

2.3.2Calculate Shift and Distribution Factors...... 16

2.3.3Calculate Element Impacts...... 18

2.4Outputs & Mechanisms...... 20

2.4.1Visualization of Operational Results...... 21

2.4.2User Interface and Displays...... 22

2.4.3ECC Alarm Processing...... 25

2.4.4Logging and Reporting...... 25

3External Access, Controls, and Administration...... 25

3.1Import, Export and API...... 25

3.2Security...... 26

3.2.1User Roles, Rights, and Access...... 26

3.3ECC Administration...... 27

3.4Controls...... 27

4Performance Metrics...... 27

4.1Performance...... 27

4.2Availability...... 28

4.3Data Retention...... 28

Appendix A:...... Terms, Acronyms, and Definitions 30

1Introduction

This document was developed by Peak Reliability (Peak)RCin consultation with the ECC Task Force to define minimum functional requirements for the Enhanced Curtailment Calculator tool.

The ECC is envisioned to serve as a congestion management tool used by Reliability Coordinators to manage power system congestion within the Western Interconnection. Peak RC views the ECC as being a reliability tool that can be used in conjunction with other RC reliability tools to ensure acceptable system performance for the Bulk Electric System.

Peak RC, as well as many TOPs in the Western Interconnection, perform Real-time Assessments using a suite of real-time reliability tools to understand how the system is performing on a pre- and post-Contingency basis. These tools generally include SCADA, state estimation, and Real-time Contingency Analysis (RTCA), and may include other advanced applications such as real-time voltage and transient stability analysis. When real-time tools indicate that the system is performing unacceptably pre- or post-Contingency or is trending toward unacceptable performance (i.e., SOL exceedance is occurring or is expected to occur), system operators are expected to take action to prevent or mitigate the condition. This action can take several forms including making adjustments in the uses of the transmission system (i.e., schedule curtailments or adjustments).

Peak Reliability Coordinator System Operators (RCSOs) use a suite of reliability tools to assess pre- and post-Contingency performance. With the addition of the ECC to the RCSO’s toolkit, the RCSOs will not only have increased situational awareness (phase I), but it is also envisioned that the RCSOs will have the ability toinitiate curtailments, ifnecessary, to ensure reliability (phase II). The ECC will have the ability to describe and quantify the contributors of flow on ECC defined elements. The RCSO will use the ECC to determine the cause (source) of unacceptably high flows that are observed in the RC’s suite of real-time tools. With this information, the RCSO in collaboration with the TOP or BA can choose to address the reliability issue through local actions or may choose to have the RC use the ECC to initiate curtailments and identify redispatch requirements necessary to relieve the condition. Any curtailments or redispatch requirementsinitiated by the ECC will be done in a fair and equitable manner according to the methodology and rulesprogrammed into the tool; the methodology and rules will be consistent with the FERC pro forma tariff.

The current Western Interconnection congestion management tool, webSAS, is used to manage the impacts of unscheduled flow on the six Transmission Paths that have satisfied the qualification process criteria described in the WECC Unscheduled Flow Mitigation Plan (UFMP). While the webSAS tool manages congestion only on the six Qualified Pathsconsistent with the current approved methodology, the ECC will have the ability to manage congestion on any BES Facility (or grouping of Facilities) in the Western Interconnection through the use of defined ECC Elements. The ECC will have the flexibility to define and update monitored Elements as necessary to ensure reliability. Peak will collaborate with TOPs to define the list of Elements based on historical performance of areas prone to congestion. Elements can also be created on the fly by RCSOs as needed based on RCSO Real-time Assessments and Operational Planning Analysis results. It is envisioned that the ECC will address implementation of the FERC-approved curtailment methodology including any resulting modifications to the current UFMP as part of Phase II. The expectation is that the webSAS tool would be retired upon completion of Phase II of the ECC project. Any proposed modifications to the approved methodology or current UFMP will undergo a stakeholder vetting process prior to implementationas part of Phase II.

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.

1.1Phase I versus Phase II

The ECC project will be broken into two phases. Phase I covers all aspects of the ECC core functionality except for the congestion management component, which falls under phase II. Phase I is intended to establish the basic functionality of the ECC that will serve as the basis for phase II functionality. Accordingly, phase I will allow the RC to identify contributing factors to SOL exceedances, but will be used for situational awareness until phase II is completed. All inputs that will be necessary to support curtailments will be included in phase I; however, the curtailment functionality itself will fall under phase II. The curtailment functionality implemented in phase II will be consistent with FERC approved methodologies and will undergo a stakeholder vetting process.

1.2What 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:
  • 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 new matrices of factors are created for each hour of the look-ahead time window.
  • Identify the sources of power flow, including tagged transactions and untagged transactionsincluding but not limited toBalancing Authority (BA) Area Control Error (ACE) contributions to flow, reserve sharing qualifying events, and tagged or untagged Dynamic Transfers.
  • Interface with e-Tag systems for Interchange Transactions information required by the ECC.
  • Interface with EIR Registry for entities’ definitions, source/sink points definitions, and POR/POD definitions.

1.3What 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).
  • 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 vettingchanges to mitigation procedures inthe stakeholder process.

2Inputs, 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.


2.1Data 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.

2.2Inputs

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.

Source of Record / Data Type / Description
Coordinated Outage System (COS) / Generator Scheduled Outage Information / Forecasted and actual generator outages and derates > 50 MWprovided to Peak by TOPs or BAs.
Coordinated Outage System (COS) / Transmission Scheduled Outage Information / Forecasted transmission outages provided to Peak by TOPs or BAs. > 100 kV.
EIDE Database / Generator Unit or Generating Station Commitment forecast / Real-time and forecasted generator MW output, service load, and pump storage or aggregation of these values for a generating station.
EIDE Database / Load Forecast Data / Forecasted load for each Balancing AuthorityAarea. The default data is the entire BA Area, but entities may work with Peak to define sub-BA areas to forecast, but Peak at a minimum would require the BA Area forecast.
NAESB EIR Registry / Mapping of Source/Sink and POR/POD data / Mapping will require a manual process by the BAs.
OATI Tagging System / E-Tag Data / E-Tag source/sink and/or POR/POD data, MW profile, transmission priority, and other relevant data for tagged transactions
OATI Tagging System / Net Scheduled Interchange / Forecasted Nnet Sscheduled Iinterchange profile for current and look-ahead hours.
OATI Tagging System / EIDE / Next-Hour Dynamic Transfers / Forecasted intra-hour coordinated transfer of energy between BAs.
Registration Reference Data / JOU Allocations (fixed) / 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.
SCADA / ACE Values / Real-time telemetered ACE values from Balancing Authorities
SCADA / Dynamic Transfer Telemetry / Real-time telemetered data for Dynamic Schedules and Pseudo-Ties reflecting the real-time value of the MW energy flow.
SCADA / BA ACE Offset Value for RSG Response / Real-time telemetered data of the ACE offset used by any BAs in response to their participation in a RSG event
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 Generating Station actual MW Output / Actual unit or generating station 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.
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 Estimatorprovides a list of generators that will respond (steady-state but not real-time) to generator outages.
West-wide System Model / System Topology / Modeled system topology for the Western Interconnection.

2.2.1West-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 Common Information Model (CIM)CSV format (or another selected format as defined through system design between OATI and Peak.) The WSM base model will include typical modeling attributes including, but not limited to:

  • Unique identifiers for equipment
  • Topology, including equipment connectivity
  • Line and transformer impedances
  • Generator maximum and minimum outputs
  • Transformer and phase shifter tap ranges

2.2.2SE (State Estimator) Savecase Data

Peak runs a state estimator (SE) using the WSM with over 125,000 measurements mapped to the network model. The ECC will read a new set of state estimator data provided by Peak once every five minutes. The state estimatorSE data provided to the ECC will either be a subset of “deltas” or states on the system states in a prescribed format that are to can be applied to the WSM base model. The actual State Estimator SE data set will be provided to OATI every five minutes via the secure file transfer protocol (SFTP) or other mechanism as agreed between OATI and Peak IT. in a prescribed format that will be determined as part of the detailed design.

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 flow
  • Interface MW limit

2.2.3ECC 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 variousshift factor calculations, including subsequent calculations for data such as weighted shift factors.

2.2.4ECC Element Definitions

The ECC will have the capability to model any Element of the WSM for monitoring WECC-wide situational awareness andof Element SOL exceedances. An Element may be modeled with or without a contingency and may represent for example, a WECC Path, a group of transmission lines, a single facility such as a transmission line or a transformer, or a facility accounting for the loss of another facility including generation, DC line, or phase shifter as contingencies . The individual facilities that make up an Element must exist in the WSM to be defined for use in the ECC. Some elements, such as jointly owned units (JOUs) or loads pseudo-tied between BAs, may require additional details in their ECC modeling definitions. The process around managing Elements in the ECC is defined in a later section of this functional specification.

2.2.5Mapping WSM to ECC

A critical component of ECC functionality includes the various layers of mapping that need to occur to the WSM. These mappings link defined BA/TOP points (Source/Sink/POR/POD) in the EIR Registry to the WSM. The ECC will use the EIR Registry to obtain POR/POD to TSP mappings and Source/Sink to BA mappings. Additional mapping groups, such as Generator Unit/ Generating Station to BA or TSP/POR/POD to BA, will be accommodated within the ECC itself as such needs are scoped with the vendor during detailed design. A critical mapping within ECC is to linkequipment from the WSM to relevant Source/Sink/POR/POD points. The ECC will have flexibility to support varying levels of granularity; for example, these mappings can be very broad to link equipment to an entire BA definition or very specific to link an individual generating unit or Generating Station to a source name. The display to create this cross-linked mapping will be built in the ECC and maintained by Peak RC staff. A Peak business process will be created to collaborate with stakeholders for initial mapping efforts as well as continued maintenance as mappings require changes.