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Real-Time RTO Power System Operations

Narrative

As the electricity industry is deregulated, and as FERC defines more clearly what the market operation tariffs will encompass, three possible Regional Transmission Organizations (RTOs) in the Western Interconnection are developing seamless interfaces for Market Participants to submit energy schedules and ancillary service bids across these 3 RTOs. The 3 RTOs are California ISO (existing ISO handling the electricity market in California), RTO West (potential RTO of many northwestern utilities), and WestConnect (potential RTO of many southwestern utilities). These 3 RTOs are developing the requirements for the Western RTO functions.

The descriptions of the functions below may or may not represent the final market rules and market operations, because these have not been finalized yet.

The following is a list of Western RTO functions related to Real-Time market operations.

Only the listed functions with asterisks are represented in the diagrams and/or step-by-step descriptions in section 2.

1.        Real-Time

a.        Operational calculations 

b.       Real-time Submittal of Schedules

c.        Real-time Submittal of Ancillary Services

d.       Normal Real-Time Dispatch Operations *

e.       Normal Generation Control Operations *

f.        Scheduling Coordinators Redispatch *

·         Redispatch

·         Notify Scheduling Coordinators of redispatch

g.       Emergency Ancillary Services *

h.       Real-Time Power System Historical Records *

Normal Real-Time Dispatch Operations

Description

RTO/ISO system operators monitor the power system and either initiate control commands directly on the power system equipment, or request the transmission owners to issue the commands, if needed for power system reliability.

Diagram

 

 

Steps for Normal Real-time Dispatch Operations

 

#

Event

Name of Process/Activity

Description of
Process/Activity

Information Producer

Information
Receiver

Name of Info Exchanged

IntelliGrid Architecture Environments

1a

Continuous

Monitor

Monitor transmission system

Transmission Power System

Transmission Owner

Transmission data

Critical Operations DAC

1b

 

Monitor

Monitor distribution system

Distribution Power System

DisCos

Distribution data

Critical Operations DAC

2a

After previous step

Monitor

Receive transmission system data via ICCP links

Transmission Owner

Data Acquisition and Control (DAC) Subsystem

Transmission data

Critical Operations DAC

2b

 

Monitor

Receive distribution system data at connecting points via ICCP links

DisCos

Data Acquisition and Control (DAC) Subsystem

Distribution data

Critical Operations DAC

2c

 

Monitor

Receive real-time RTO data via ICCP links

Other 2 RTOs

Data Acquisition and Control (DAC) Subsystem

Real-time data from other RTOs

Critical Operations DAC

3a

After previous step

Monitor

Provide real-time data to RTOs via ICCP links

Data Acquisition and Control (DAC) Subsystem

Other 2 RTOs

Real-time data to other RTOs

Critical Operations DAC

3b

 

Monitor

Monitor power system operations

Data Acquisition and Control (DAC) Subsystem

RTO Operator

User Information

Intra-Control Center

3c

 

Monitor

Provide real-time raw data for State Estimator

Data Acquisition and Control (DAC) Subsystem

Real Time Network Analysis Sequence

Subset of real-time data

Intra-Control Center

3d

 

Import power system model

Provide power system model

Power System Model

Real Time Network Analysis Sequence

Power system connectivity and characteristics

Intra-Control Center

4

After previous step

Analyze power system

Issue alarms for potential power system contingencies

Real Time Network Analysis Sequence

RTO Operator

Alarms

 User Interface

5

After previous step

Control

Authorize or override control commands

RTO Operator

Data Acquisition and Control (DAC) Subsystem

Control commands

 User Interface

6a

After previous step

Control

Issue transmission equipment instructions by phone

Data Acquisition and Control (DAC) Subsystem

Transmission Owner

Control commands

Critical Operations DAC

6b

 

Control

Issue distribution equipment instructions by phone

Data Acquisition and Control (DAC) Subsystem

DisCos

Control commands

Critical Operations DAC

7a

After previous step

Control

Actual direct control over transmission system equipment

Transmission Owner

Transmission Power System

Control commands

Critical Operations DAC

7b

 

Control

Actual direct control over distribution system equipment

DisCos

Distribution Power System

Control commands

 Critical Operations DAC

 

Normal Generation Control (NGC)

Description

RTO/ISO system operators dispatch generation according to energy schedules:

- RTO/ISO SCADA system monitors power system

- RTO/ISO EMS system performs Automatic Generation Control (AGC)

- RTO/ISO Market Operations system analyzes transmission capacity and reliability

- RTO/ISO Market Operations system balances energy/ancillary services

RTO/ISO EMS system monitors interchange schedules with internal and external Control Areas, directly involving RTO System Operator, RTO/ISO SCADA EMS, Scheduling Coordinators, Area Control Centers, Generators, performing Automatic Generation Control, with key interfaces between

1. RTO SCADA/EMS and Generators

2. RTO SCADA/EMS and TransCos

3. RTO SCADA/EMS and DisCos

4. RTO SCADA/EMS and other RTO SCADA/EMS

5. RTO SCADA/EMS and Scheduling Coordinators

Diagram

 

 

Steps for Normal Generation Control

#

Event

Name of Process/Activity

Description of
Process/Activity

Information Producer

Information
Receiver

Name of Info Exchanged

IntelliGrid Architecture Environments

1

On-going

Submit energy schedules

(1) Submit Balanced Energy Schedules, including self-provided Ancillary Services Schedules, any inter-SC trades, and any generation limit changes, until Schedule Close

Scheduling Coordinators

Market Interface Web Server

Energy schedules

RTOs/Market Participants

2

Submittal of an energy schedule

Validation

(2) Indicates valid input or indicates clerical & format errors

Market Interface Web Server

Scheduling Coordinators

Energy schedules

RTOs/Market Participants

3

Correction

Correction

(3) Corrects errors

Scheduling Coordinators

Market Interface Web Server

Energy schedules

RTOs/Market Participants

4a

Valid energy schedule submitted

Energy Schedule Analysis

(4a) Provides Day-Ahead Energy Schedules

Market Interface Web Server

Energy Schedule Analysis

Energy schedules

RTOs/Market Participants

4b

Simultaneous with previous step

Energy Schedules to RTOs

(4b) Provides Day-Ahead Energy Schedules relevant to each RTO

Market Interface Web Server

Other 2 RTOs Energy Schedule Processing

Energy schedules

RTOs/Market Participants

5a

Analysis of energy schedules

Adjustment to energy schedules

(5a) Adjusts any unbalanced schedules and stores validated input as proposed schedules

Energy Schedule Analysis

RTO Energy & A/S Schedules

Energy schedules

Intra-Control Center

5b

Simultaneous with previous step

Adjusted energy Schedules to RTOs

(5b) Provides adjusted and validated cross-RTO schedules

Energy Schedule Analysis

Other 2 RTOs Energy Schedule Processing

Energy schedules

RTOs/Market Participants

5c

Simultaneous with previous step

Apply existing energy schedule contracts

(5c) Enter existing contracts

Existing Transmission Contracts

RTO Energy & A/S Schedules

Existing energy schedule contracts

Intra-Control Center

6a

Day Ahead Market Close

Time-based trigger

(6a) Initiates Day Ahead security analysis verification after Schedule Close

Time Line Manager Function

Congestion Management Function

Day Ahead Energy schedules

Intra-Control Center

6b

Simultaneous with previous step

Retrieve Day-Ahead schedules

(6b) Retrieves all Day Ahead schedules

RTO Energy & A/S Schedules

Congestion Management Function

Day Ahead Energy schedules

Intra-Control Center

6c

Simultaneous with previous step

Cross-RTO security analysis

(6c) For cross-RTO schedules, validates schedules, adjusts any unbalanced schedules, and provides as proposed schedules

Other 2 RTOs Energy Schedule Processing

RTO Energy & A/S Schedules

Day Ahead Energy schedules

RTOs/Market Participants

7a

After previous step

Security Analysis

(7a) Verifies schedules meet intra-zonal & connection point security requirements

Congestion Management Function

RTO Energy & A/S Schedules

Day Ahead Energy schedules

Intra-Control Center

7b

Simultaneous with previous step

Cross-RTO security analysis

(7b) For cross-RTO schedules, provide results of Congestion Management analysis

Congestion Management Function

Other 2 RTOs Energy Schedule Processing

Day Ahead Energy schedules

RTOs/Market Participants

8a

After previous step

Post results of security analysis

(8a) Posts results of Congestion Management analysis of schedules

RTO Energy & A/S Schedules

Market Interface Web Server

Day Ahead Energy schedules

RTOs/Market Participants

8b

Simultaneous with previous step

Post results of cross-RTO security analysis

(8b) Posts results of Congestion Management analysis of cross-RTO schedules

Other 2 RTOs Energy Schedule Processing

Market Interface Web Server

Day Ahead Energy schedules

RTOs/Market Participants

8c

Simultaneous with previous step

Cross-RTO conflicts

(8c) Notify of cross-RTO conflicts or inconsistencies

Other 2 RTOs Energy Schedule Processing

RTO Scheduler

Cross-RTO conflicts

RTOs/Market Participants

9

After step 8c

Resolve cross-RTO conflicts

(9) Posts resolutions to cross-RTO conflicts and inconsistencies

RTO Scheduler

Market Interface Web Server

Resolved cross-RTO conflicts

RTOs/Market Participants

10

After previous step

Notify Scheduling Coordinators

(10) Notifies of schedule acceptances and rejections

Market Interface Web Server

Scheduling Coordinators

Accepted Energy schedules

RTOs/Market Participants

11

Upon request by Scheduling Coordinators

Revisions to energy schedules

(11) Enter revisions to schedules as needed, until Revision Close

Scheduling Coordinators

Market Interface Web Server

Revised energy schedules

RTOs/Market Participants

 

Scheduling Coordinators Redispatch (SCRD)

Description

Scheduling Coordinators to submit energy schedule adjustments in the Hour-Ahead market if needed due to power system emergencies or other factors, and the RTOs/ISOs to validate the submittals. This function involves the Scheduling Coordinators, RTOs/ISOs, Auditors, and other Market Participants.

 

Diagram

,

 

 

Steps for Scheduling Coordinators Redispatch

#

Event

Name of Process/Activity

Description of
Process/Activity

Information Producer

Information
Receiver

Name of Info Exchanged

IntelliGrid Architecture Environments

(1)

Emergency event

Provide alarm information

Notifies SCs of emergency congestion and other problems

Data Acquisition and Control (DAC) Subsystem

Market Interface Web Server

Emergency alarm data

RTOs/Market Participants

(2)

 

Notify Scheduling Coordinators

Notifies of problems requiring rescheduling

Market Interface Web Server

Scheduling Coordinators

Emergency alarm data and rescheduling request

RTOs/Market Participants

(3)

 

Update schedules

Update schedules due to generator outage or reduced transmission rights

Scheduling Coordinators

Market Interface Web Server

Updated schedules

RTOs/Market Participants

(4)

 

Validate schedules

Update valid schedules

Market Interface Web Server

Energy Schedules

Validated updated schedules

RTOs/Market Participants

(5)

 

Analyze updated schedules

Analyze updated schedules

Energy Schedules

Maintenance Outage Function

Updated schedules

RTOs/Market Participants

(6)

 

Review updated schedule

Review updated schedules

Maintenance Outage Function

RTO Operator

Updated schedule

Intra-Control Center

(7)

 

Approve updated schedule

Verify updated schedule is acceptable

RTO Operator

Energy Schedules

Approved updated schedule

Intra-Control Center

(8a)

 

Update operating plan

Update operating plan

Energy Schedules

Operating Plan

Updated Operating plan

Intra-Control Center

(8b)

 

Indicates acceptance or rejection

Accepts or rejects updated schedule

Energy Schedules

Market Interface Web Server

Acceptance or rejection notice

RTOs/Market Participants

(9a)

 

Indicates acceptance or rejection

Notify of acceptance or rejection of updated schedule

Market Interface Web Server

Scheduling Coordinators

Acceptance or rejection notice

RTOs/Market Participants

(9b)

 

Provide updated Operating Plan

Provide updated Operating Plan

Operating Plan

Other RTOs

Operating Plan

RTOs/Market Participants

 

Emergency Ancillary Services (EAS)

Description

Scheduling Coordinators submit Hour-Ahead bids for ancillary services: reserve, regulation, frequency response, etc., in order to resolve emergencies conditions, and the RTOs/ISOs to validate the submittals.

RTO/ISO Market Operations system manages market external price caps (if they exist in the respective market).

Diagram

 

 

Steps for Emergency Ancillary Services

#

Event

Name of Process/Activity

Description of
Process/Activity

Information Producer

Information
Receiver

Name of Info Exchanged

IntelliGrid Architecture Environments

(1a)

Emergency on power system

Request additional A/S

Request additional ancillary services

RTO Operator

Market Interface Web Server

Emergency request

RTOs/Market Participants

(1b)

 

Override Operating Plan

Manually override Operating Plan in an emergency

RTO Operator

Operating Plan

Override

Intra-Control Center

(1c)

 

Authorize emergency dispatch

Authorize emergency dispatch procedures

RTO Operator

Area & Resource Operation Centers

Emergency dispatch

RTOs/Market Participants

(2a)

 

Notify Scheduling Coordinators

Notify SCs of A/S request

Market Interface Web Server

Scheduling Coordinators

Notification of need for A/S

RTOs/Market Participants

(2b or 6b)

 

Update Balancing energy stack

Update Balancing Energy Stack to indicate that emergency conditions apply

Operating Plan

Balancing Energy Stack

Update

Intra-Control Center

(3a)

 

Submit A/S bids

Submit bids for ancillary services

Scheduling Coordinators

Market Interface Web Server

A/S bids

RTOs/Market Participants

(4a)

 

Analyze A/S bids

Analyze A/S bids

Market Interface Web Server

Ancillary Services Procurement Analysis

A/S bids

RTOs/Market Participants

(5a)

 

Accept A/S bid

Accept A/S bid

Ancillary Services Procurement Analysis

Market Interface Web Server

A/S bids

RTOs/Market Participants

(5b)

 

Update Operating plan

Update Operating Plan with new A/S

Ancillary Services Procurement Analysis

Operating Plan

Updates to Operating Plan

Intra-Control Center

(6a)

 

Notify of A/S bid acceptance

Notify of A/S bid acceptance

Market Interface Web Server

Scheduling Coordinators

Bid Acceptance

RTOs/Market Participants

(6c)

 

Provide updated Operating Plan

Provide updated Operating Plan

Operating Plan

Area & Resource Operation Centers

Operating Plan

RTOs/Market Participants

(6d)

 

Provide updated Operating Plan

Provide updated Operating Plan

Operating Plan

Transmission Owner

Operating Plan

RTOs/Market Participants

(6e)

 

Provide updated Operating Plan

Provide updated Operating Plan

Operating Plan

Other 2 RTOs

Operating Plan

RTOs/Market Participants

7

 

Issue validated volt/var and AGC raise/lower or setpoint commands

Issue validated volt/var and AGC raise/lower or setpoint commands

Balancing Energy Stack

Area & Resource Operation Centers

Control commands to implement Operating Plan

RTOs/Market Participants

 

RT Power System Historical Records (PSH)

Description

All real-time conditions and actions must be logged and recorded in historical files.

Diagram

 

 

Steps for Historical Records

 

#

Event

Name of Process/Activity

Description of
Process/Activity

Information Producer

Information
Receiver

Name of Info Exchanged

IntelliGrid Architecture Environments

1a

At end of each Settlement Period

Provide power system model and state estimated data

Provide power system model and state estimated data

Real Time Network Analysis Sequence

Network Sensitivity Calculations

Power System Model

State Estimated data

Intra-Control Center

1b

 

Provide real-time power system data

Provide real-time power system data

Data Acquisition and Control (DAC) Subsystem

Network Sensitivity Calculations

Real-time data

Intra-Control Center

1c

 

Provide power system data snapshots, calculated data, disturbance data, alarms, and other key data for historical records

Provide power system data snapshots, calculated data, disturbance data, alarms, and other key data for historical records

Data Acquisition and Control (DAC) Subsystem

Historical Records

Data snapshots

Intra-Control Center

1d

 

Provide transmission loss calculations

Provide transmission loss calculations

Network Sensitivity Calculations

Historical Records

Loss calculations

Intra-Control Center

1e

 

Provide MOD generation information

Provide MOD generation information

Merit Order Dispatch Function

Historical Records

Merit Order Dispatch data

Intra-Control Center

1f

 

Provide operating plan information

Provide operating plan information

Operating Plan

Historical Records

Operating Plan

Intra-Control Center

2

 

Post required power system information

Post required power system information

Historical Records

Market Interface Web Server

Posting of the historical records

RTOs/Market Participants

 

 

 

 

 

IntelliGrid Architecture
Copyright EPRI 2004