Transcript Bruce + West Limits - Independent Electricity System Operator

Bruce + West Bottling
The IESO Transmission System
• The transmission system is made up of a
number of circuits all of which have unique
capabilities and thermal limitations.
• Our generation dispatching tool is designed to
recognize these limitations and dispatch
resources appropriately in order to respect them.
• These limitations at times lead to an inability to
utilize available generation due to a lack of paths
out of a region – Bottled Energy
The IESO Transmission System
• These values are dynamic and can change every
5 minutes based on temperature, wind speed,
day/night etc...
• Result of which are two schedules (constrained
and unconstrained)
• As these limitations are automatically respected
there is no formal operating instruction for how
to manage these limits.
• In other words, no SCO exists for these subareas
Circuit Thermal Ratings
• The thermal capabilities of the circuits are
provided to us from each circuit’s asset owner
• Revised thermal limits, in the form of a lookup
table are provided to the IESO for each circuit
every hour to reflect current real time
conditions.
Bottling Estimates
•Bottled generation is normally calculated by zone
whereby:
•Bottled Gen = Available Gen-Zonal Demand
-Ability to leave Zone
•Zones are generally divided by transmission
interfaces.
Bruce + West Transmission
BRUCE
FABCW
MICH-ONT
INTERFACE
WEST
SOUTH WEST
Interface Limits
• FABCW is the Flow Away from the Bruce Complex +
Wind
• FABCW limit is dependent on a number of factors
including actual flow on the BLIP interface.
• This limit is required to preserve plant stability in the area
as well as to protect against voltage collapse post
contingency.
• BLIP is the Buchanan Longwood Input.
• BLIP flow 0 is generally limited to 3,000 MW and Negative
BLIP (NBLIP) generally varies between 500 to 1,500 MW.
• Both limits are based on voltage limitations
Interface Limits
• At times, the transmission capability internal to a
zone may be more limiting than the interface
limit.
• In these cases, the traditional methodology for
measuring Bottling is not adequate
• This is the case in the West and thus the zone was
divided into 4 sub-areas, each divided by a
boundary.
• The traditional bottling equation is then applied
to each individual sub-area.
The WEST
Each sub-area contains both
generation and load.

MICHONT

G

```
L
G
`L
`
`
`

NBLIP
≈ 500 - 1,500 MW
G
G
L
L
Boundary Thresholds
1. 3,058 MW – 4,045 MW
2. 3,010 MW – 3,981 MW
3. 2,218 MW – 2,836 MW
Bottling In The West
• These four boundary thresholds are based on
simulations done by the IESO.
• The simulation was designed to maximize
generation.
• The boundary threshold values are the
estimated maximum total generation that can be
produced before a thermal limit of a circuit out
of that sub-area begins to encroach on its limit.
• These boundary threshold values are used as
estimates for modelling purposes only.
Bottling In The West
• Because these boundary are a result of thermal
restrictions, each boundary has a different
threshold for a number of temperature ranges.
• The threshold range is based on temperatures
from -20°C to 35 °C and change by 5°C
increments
Boundary Thresholds
Temperature (°C)
Boundary 1 (MW) Boundary 2 (MW) Boundary 3 (MW)
-20
4,045
3,981
2,836
-15
3,968
3,905
2,786
-10
3,885
3,824
2,737
-5
3,789
3,729
2,684
0
3,711
3,652
2,635
5
3,629
3,571
2,586
10
3,531
3,476
2,537
15
3,431
3,376
2,467
20
3,353
3,300
2,418
25
3,256
3,205
2,353
30
3,155
3,105
2,287
35
3,058
3,010
2,218
Looking Forward
• Transmission enhancements throughout the
province
• The shutdown of coal fired generation
• Bottled numbers are expected to decrease
Thank You!
Questions?