managing reliability and the markets with pi

California Independent System Operator

Managing Reliability and the Markets with PI

PI System Users Conference

OSI Software, Inc.

April 2-5, 2000

Jim DetmersDirector, Engineering and Maintenance



Some Facts About the California ISO

• Consists of PG&E, SCE, and SDG&E Service Territories.

• Covers 124,000 square miles.

• 21,000 Circuit Miles of Transmission

• Approximately 600+ Generators

• 45,000 Megawatt Summer Peak Load

• 164 Billion KWh of Energy Delivered

to 27 Million Californians.

• Consumers Use Over $23 Billion of Energy Annually.


Cal ifornia IndependentSy stem Operator

Before After

POWERGENERATORS

UTILITY

CUSTOMERS

PO WER GENERATORS PO WER MARKE TERS

SCHEDULING COORDINATORS

CALIFORNIA IS O

CUSTOMERSUTILITY

ES Ps

De-Regulating the Electric Industry in California


AB 1890 signed

AB 1890 goes into

effect

ISO Restructuring

Trust established

$191 million credit facility

for ISO start-up and

development costs

Sept. ‘96 Dec. ‘96 Jan. ‘97 May ‘97 July.-Oct. ‘97 Oct.‘97-Mar.’98 Mar. ‘98

First Staff is Hired

ISO staff & Executives

hired

Operational Dry

Run

Staff Training

Initial Applications & infrastructure

delivered

Mar.‘97

Vendor Contracts

Signed

How the California ISO was Formed


• Assure that the Transmission Grid is Reliable.

• Access to the Transmission Grid is Open and Non-discriminatory.

• Electricity Markets Function Efficiently and Effectively.

The ISO’s Basic Functions


Maintain National and Regional Reliability Standards.

– Operating Reserve - Automatic Generation Control

– Frequency Response and Bias - Time Control

– Control Performance - Inadvertent Interchange

– Control Surveys - Control and Monitoring Equipment

– Backup Power Supply

Maintain Operating Transfer Capability (OTC) between other Control Areas

Maintain Operating Limits in the Local Area Transmission System.

The ISO Reliability Requirements


Real-Time Markets

Ancillary Services MarketsRegulation - Spinning - Non-Spinning - Replacement

Out-of-Market Calls (OOM)

Emergency Measures

Forward Energy MarketsDay Ahead Hour Ahead

“Reliability through Markets”


Day AheadMarket

Hour AheadMarket

RealTime

Time

Suppliers Bid - Energy & Ancillary Services

Load Estimated

Transmission Capacity Analyzed Inter-Zonal Congestion Management

Suppliers Re-Submit Bids

Schedules Balanced

RegulationDispatched

Suppliers Bid - Energy & Ancillary Services

Load Estimated

Transmission Capacity Analyzed Inter-Zonal Congestion Management

Suppliers Re-Submit Bids

Schedules Balanced

Suppliers Bid Energy

Manage Loads

Manage Frequency &Transmission

System Balanced

From Schedule to Reality


?????

Load

Regulation (AGC)

10 Minute MarketBalancing Energy

Uninstructed DeviationReliability Must Run

Hour Ahead Energy Market

Day Ahead Energy Market

Balancing Energy Ties

One Hour Time

One Hour in the Market


• INITIAL ISO COMPUTER SYSTEMS:

• Scheduling Infrastructure (SI)

• Scheduling Applications (SA)

• Energy Management System (EMS)

• Meter Data Acquisition System (MDAS)

• Balance of Business System (BBS)

________________________________

The Tools That Make It Work

•ADDITIONAL COMPUTER SYSTEMS:

•Plant Information System (PI)

•Generator Communications Project (GCP)


Why Use PI?

Historical Operational Data.

Reliability and System Security

Compliance with Market Bids

Market Analysis


Real-time

• Regulation Response.

• Trend System Loads.

• Monitor Critical Transmission System Components.

After the Fact

• Retrieve Operational Data.

• Analyze Transmission System Disturbances.

• Reliability Management System (RMS) reporting.

Examples of Using PI


The Dynamics of Regulation

• Provides Real-Time Difference Between Load and Generation

• Maintains Frequency and Interchange Schedules.

• Unique Ancillary Services Market.

• A Regulation Set-Point Signal is Calculated Every 4 Seconds.

• Regulation Market Bids are Dispatched Directly from the ISO.

“Real-Time” Example: ISO Regulation

Load Generation

60Hz


The Problem with Regulation

• New Market Environment Greatly Increased Regulation Requirements.

• Regulation Costs California Consumers up to $1,000,000 Each Day.

• Regulation is Complex and Difficult to Analyze.– Multiple Generation Suppliers Bid to Provide Service

– Market Determines Which Units Will Provide Regulation Each Hour

– Dynamic Load Determines Regulation Need



Regulation is Bid in Market


Using PI to Find the Regulation Problem

• Process Book Trends of Each Generator on Regulation

• Hourly Deviations Between Set-Points and Actual MW Output

• List of Generators Based on their Ability to Deliver Regulation

• Real-Time Updates of Generators Selected by the Market

• Net Regulation Trend Display.



Good Regulation Response

0

50

100

150

200

250

0:1

5

0:1

7

0:1

9

0:2

1

0:2

3

0:2

5

0:2

7

0:2

9

0:3

1

0:3

3

0:3

5

0:3

7

0:3

9

0:4

1

0:4

3

0:4

5

0:4

7

0:4

9

0:5

1

0:5

3

0:5

5

0:5

7

0:5

9

Set-Point Signal

Actual Output



PI Trend - Good Regulation Response


Delay in Response Time

0

50

100

150

200

250

300

16

:20

16

:21

16

:22

16

:23

16

:24

16

:25

16

:26

16

:27

16

:28

16

:29

16

:30

16

:31

16

:32

16

:33

16

:34

16

:35

16

:36

16

:37

16

:38

16

:39

16

:40

Set-Point Signal

Actual Output



Generator Not Following the Set-Point

200

250

300

350

11

:30

11

:34

11

:38

11

:42

11

:46

11

:50

11

:54

11

:58

12

:02

12

:06

12

:10

12

:14

12

:18

12

:22

12

:26

12

:30

12

:34

12

:38

12

:42

12

:46

12

:50

12

:54

12

:58

13

:02

13

:06

13

:10

13

:14

13

:18

13

:22

13

:26

13

:30

Actual Output

Set-Point



Improper Regulation Response


Uninstructed Deviation of a Non-regulating Unit

0

50

100

150

200

250

300

350

400

450

500

550

600

650

700

0:0

0

1:0

0

2:0

0

3:0

0

4:0

0

5:0

0

6:0

0

7:0

0

8:0

0

9:0

0

10

:00

11

:00

12

:00

13

:00

14

:00

15

:00

16

:00

17

:00

18

:00

19

:00

20

:00

21

:00

22

:00

23

:00

0:0

0

Market Schedule

Actual Output

$39

$35

$132

$45

$150

$50

$42

$55

$42

$35

$150

$35

$35Uninstructed DeviationUnit Not in Market but,

Chasing Price

Uninstructed DeviationUnit in Market and

Chasing Price

Uninstructed Deviation

Unit Not in Market, but at Minimum Load Until Called



Solving the Regulation Problem

The Regulation Problem was Caused by Generators Not Responding

to Control Signals. To Solve This Problem, the ISO is:

• Establishing Direct Communications with the Generators

• Correcting Improper Conversions for the AGC Set-Point Signal.

• Penalizing Units Deviating from Schedules because of Spot Prices.



Results of Solving the Regulation Problem

• Correcting Regulation Problems Improves System Reliability.

• Reducing Regulation Requirements Enhances Market Competition.

• Reduced Requirements Result in Savings up to $300,000 a Day.

• The PI System Easily Paid for Itself After a Few Weeks of Operation.



On September 30, 1999, under-frequency was experienced in the

Western United States for about two hours.

It appeared that the California transmission system was the cause of

the event because:

• Higher than Expected Loads.

• Overloads on a Major Intertie Between Oregon and California.

• Shortage of Operating Reserves.

• Interruptible Load Shedding in California was Implemented.

“After the Fact” Example: Disturbance Analysis


Using PI to Analyze the Disturbance

Develop Trends For:

• Load

• Frequency

• Area Control Error (ACE)

• Flows on the Overloaded Transmission Lines

• Regulation Reserves.



ISO Load

September 30, 1999 Incident

37000

37500

38000

38500

39000

39500

40000

40500

14:45 15:14 15:43 16:12 16:40 17:09 17:38

Time

MW



PI Trend of Frequency and Load




ISO ACE and FrequencySeptember 30, 1999 14:45-17:00 PAST Incident

-800

-600

-400

-200

0

200

400

600

14:45 15:00 15:15 15:30 15:45 16:00 16:15 16:30 16:45 17:00

Time

AC

E (

MW

)

59.9

59.92

59.94

59.96

59.98

60

60.02

60.04

60.06

Fre

qu

en

cy

(H

z)

ACE

FrequencyTimestamp: 1

Timestamp Summary

1 - Frequency bottoms out at 59.912 Hz.2 - CISO declares Stage 2 emergency.3 - Interruptible load shedding begins.

2 3


PI Trend of Frequency and ACE



Results of the Analysis

PI is a Valuable Tool for Determining the Causes of System

Disturbances and Teaching Us How to Prevent Them from

Occurring Again.

• Losses of Generation Outside of the California System Initiated the Event.



• PI can Be Used to Improve the Efficiency of the Markets and Reduce Costs to Consumers.

• PI can Be Used to Determine the Cause of Problems and Help to Improve System Reliability.

• PI has helped the ISO Realize its Mission Statement of “Reliability Through Markets” and to Meet ISO Corporate Goals.

Conclusions

managing reliability and the markets with pi

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