system load calculation for aep-texas
DESCRIPTION
System Load Calculation for AEP-Texas. AEIC Annual Load Research Conference Reno, Nevada September 10-13, 2006. Kirk Schneider American Electric Power Tulsa, Oklahoma. Introduction. What We Did Why We Did It How We Did It What We Found So What?. - PowerPoint PPT PresentationTRANSCRIPT
Kirk Schneider
American Electric Power
Tulsa, Oklahoma
AEIC Annual Load Research Conference Reno, Nevada
September 10-13, 2006
System Load System Load Calculation for AEP-Calculation for AEP-
TexasTexas
• What We Did
• Why We Did It
• How We Did It
• What We Found
• So What?
Introduction
The American Electric Power System
•ERCOT became single Control Area 7/31/01
•Companies stopped checking tie lines.
•Installed IDRs on a Number of Tie-Lines
•Verified IDR Data for generation and tie-lines
•Rate filing for TCC and TNC later this year.
•Update loss studies.
•Update demand studies
What We Did
What is System Load?
• Total power consumption on system
• Measure Power Received from Generators
• Measure Power Flow at Interconnect Points
• Can directly measure load, but not losses
“Top-Down” System Load Calculation
I
II
G
G30
0 M
W
20
0 M
W
10 MW
20 M
W
40 MW
Generation: 300 + 200
Interchange: -10-20
+40 --------
Net Load: 510 MW
“Bottom-Up” Load Calculation
I
II
G
G
Load: RES 190 COM + 100 IND + 60 WHL + 140
Losses: + 30 ------------------Load: 520 MW
UFE: - 10 MW
Power Consumption in North American Grid
• No Boundary Metering
• Power is consumed the instant it is generated
• Power Consumed = Power Generated
• Power Consumed = Power used + power “lost”
ERCOT Transmission System
ERCOT System Load
• Connected to grid with 3 DC ties
• System Load = generation + power
imported over DC ties – power exported
over DC ties
• SYSTEM LOAD = GENERATION – NET
INTERCHANGE
• EPS Meters on Generation and DC Ties
AEP-Texas System Load
• Texas Central Co. (South Texas)
• Texas North Co. (West Texas)
• TCC ~ 30 Gens, 50 Interconnects
• TNC ~ 20 Gens, 40 Interconnects
Texas Central Transmission System
Texas North Transmission System
•Demand Studies
• Σ Sales * Loss Factor = Estimated System Load
•Loss Studies
• Losses = System Load – Σ Sales
• Transmission Settlements
• Unbilled Sales
• Checks and Balances
• All Assume System Load is Correct
Why AEP Needs System Load
•About 12 complete – meter and CT / PTs
•About 24 meter only using existing CT / PTs
•Accuracy of Meters
•Leveraging Existing Metering In South Texas
How did We Implement AEP-Texas Tie-Line Metering?
TCC Ties to South Texas EC
How Are We Collecting and Analyzing the Data?
•Collecting Data Using MV-90 System
•Data Validation
•Analyzing Data Using SAS
•Sent to CEAS System
PROBLEMS!
• Gaps in IDR Data
• Suspicious Looking Data
• Missing Meters
• Problems Getting Data from ERCOT
SCADA to the Rescue!
• PI Database Installed Oct 2004
• Analog Measurements
• Accessible with ODBC or OLE
• SAS Table Containing SCADA Data
Data Validation
•Use SCADA Data to Validate IDR Data
•SCADA Strengths Complement IDR Data
•Use SCADA Data to Fill IDR Data Gaps
•Examples
Everything’s All Right – Generator 1
Everything’s All Right – Generator 2
Everything’s All Right – Tie 1
Everything’s All Right – Tie 2
Good Enough – SCADA at opposite end of line
Better than Nothing – SCADA at opposite end, load along
line
Load Outside Boundary of Meters
Gap In IDR Data - Generator
Gap in IDR Data - Line
SCADA Goes “Flat-Line” for Short Period – Gen
SCADA Goes “Flat-Line” for Short Period – Line 1
SCADA Goes “Flat-Line” forShort Period – Line 2
SCADA Goes “Flat-Line” for Short Period – Line 3
SCADA Goes “Flat-Line” for Long Period – Line 1
SCADA Goes “Flat-Line” for Long Period – Line 2
SCADA Goes “Flat-Line” – Long Period - Gen
SCADA Resolution Problem – Small Line
SCADA Resolution Problem – Line
Time-Synch or Resolution??
No SCADA Available – Wholesale POD’s
General SCADA Failure – Example 1 Gen
General SCADA Failure – Example 2 Gen
General SCADA Failure – Example 3 Line
General SCADA Failure – Example 4
General SCADA Failure – Example 5 Line
Suspicious Generator Data
Impact on System Load Calc
Meter Configuration
Using Alternate SCADA Points
IDR Data vs. SCADA
• IDR Strengths
•True integrated values
•Distributed data collection
•Lower cost than SCADA
• SCADA Strengths
•Time synch extremely accurate
•Data available real-time
•Multiple backup measurements
• Together Provide Very Reliable, Accurate Data
Top Down vs. Bottom UpSummer
Top Down vs. Bottom Up Winter
Top Down System vs. Bottom Up At Meter
System Losses
Percent Losses
Summary of Results
• SCADA Bailed Us Out
• Strengths of IDR Data and SCADA Complementary
• Customer Load Aggregation Matches System Load
• Able to Perform Loss Study
So What?
• We Can Measure AEP-Texas System Load
• Two Measurements Better Than One
• Understand Your System Load Data
• Accurate System Load = $$$
• Let’s Work Together Again!