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PJM2009PJM DOCs #
Reliability Concerns towards Frequency Response
and Overview of BAL 001 and BAL 003
H.W. Herbsleb
Performance Compliance
PJM20092PJM DOCs #
Control Time line for frequency and balancing
2
BALANCING AND FREQUENCY CONTROLExcerpt from : A Technical Document Prepared by the NERC Resources Subcommittee
PJM2009PJM DOCs #
Frequency Performance
Page 3
Arresting Period Rebound Period Recovery Period
Compliance time for Bal-002
PJM20094PJM DOCs #
Different speed of response of responsive units
Page 4
Blue = gas-turbine unit on governor controlRed = (fast) hydro-power unit on governor controlGreen = (ideal) steam-turbine unit on governor control
PJM20095PJM DOCs #
Frequency Response Basics (Using a 1400 MW generation loss event as an example)
Page 5
0
200
400
600
800
1000
1200
1400
1600
1800
2000
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
Time (Seconds)
Go
vern
or/
Lo
ad
Resp
on
se (M
W)
59.60
59.65
59.70
59.75
59.80
59.85
59.90
59.95
60.00
60.05
60.10
Fre
qu
en
cy (H
z)
Governor Response
Load Response
Frequency
A
B
Cc
NERC Frequency Response =
Generation Loss (MW) FrequencyPoint A-FrequencyPoint B
Slope of the dark green line illustrates the System Inertia (Generation and Load). The slope is P/(D+2H)
Pre Event Frequency
Frequency Nadir:
Generation and Load Response equals the generation loss
Settling Frequency:
Primary Response is almost all deployed
PJM20096PJM DOCs #
Frequency Response Concerns
Frequency Response is declining in Eastern Interconnection
Various factors are influencing
When is frequency response too low?
Primary Control Frequency Response is being withdrawn
Primary inertial generation being supplanted by non-inertial resources wind, solar, electronically coupled resources
What is their response to frequency excursions?
What is their susceptibility to tripping during frequency excursions?
Load characteristics are changing
Unknown frequency response characteristics
Current modeling is insufficient to analyze the phenomenon
6
7Eastern Interconnection Mean Primary Frequency Response Trend
Eastern Interconnection Mean Primary Frequency Response Projected
8
PJM20099PJM DOCs #
Classic Frequency Excursion Recovery
9
Excursion Recovery
A = 60.000
C = 59.812
B = 59.874
59.750
59.775
59.800
59.825
59.850
59.875
59.900
59.925
59.950
59.975
60.000
60.025
60.050
-30 0 30 60 90 120 150 180 210 240 270 300 330 360 390 420
Time (Seconds)
Frequency (Hz)
Recovery Completed, TV
10
Typical Frequency Traces
Following a Unit Trip
11
Inertial Response Variability
Light Inertia
High Inertia
PJM200912PJM DOCs #
Frequency Response Basics
Whys and Wherefores (things to examine)
Deadband currently typical setting is at 36 mHz ERCOT greatly improved frequency response by reducing
deadband to 16.6 mHz
Sliding pressure controls
MW setpoints limited time of response
Blocked governor response
Once-through boilers
Gas Turbine inverse response
12
13
Frequency Response
-150.00
-100.00
-50.00
0.00
50.00
100.00
150.00
59.50 59.55 59.60 59.65 59.70 59.75 59.80 59.85 59.90 59.95 60.00 60.05 60.10 60.15 60.20 60.25 60.30 60.35 60.40 60.45 60.50
Hz
MW
Ch
an
ge
Droop Setting 5.00%
Deadband Setting
Hz600.000
00Capability (MW)
0.036
Close up look at +/-0.036 Hz Dead Band with Step Implementation
600 MW Generator
Step response at dead-band.
PJM200914PJM DOCs #
14
Frequency Response Initiative
PJM200915PJM DOCs #
FRI Objectives
Coordinate all NERC standards development and performance analysis activities related to frequency response and control
Identify specific frequency-related reliability factors
Identify root causes of changes in frequency response
Identify practices and methods to address root causes
Consider impacts of integration of new generation technologies (such as wind, solar, and significant nuclear expansion)
15
PJM200916PJM DOCs #
BAL 001 Requirements
R1-
R2-
R3 - Each Balancing Authority providing Overlap Regulation Service shall evaluate Requirement R1 (i.e., Control Performance Standard 1 or CPS1) and Requirement R2 (i.e., Control Performance
Standard 2 or CPS2) using the characteristics of the combined ACE and combined Frequency Bias
Settings
R4 - Any Balancing Authority receiving Overlap Regulation Service shall not have its control performance evaluated (i.e. from a control performance perspective, the Balancing Authority has shifted
all control requirements to the Balancing Authority providing Overlap Regulation Service).
PJM200917PJM DOCs #
BAL 001 Measurements
M1- Each Balancing Authority shall achieve, as a minimum, Requirement 1 (CPS1) compliance of 100%. CPS1 is calculated by converting a compliance ratio to a compliance
percentage as follows:
CPS1 = (2 - CF) * 100%
The frequency-related compliance factor, CF, is a ratio of all one-minute compliance
parameters accumulated over 12 months divided by the target frequency bound.
M2- Each Balancing Authority shall achieve, as a minimum, Requirement R2 (CPS2) compliance of 90%. CPS2 relates to a bound on the ten-minute average of ACE. A
compliance percentage is calculated as follows:
The violations per month are a count of the number of periods that ACE clock-ten-minutes
exceeded L10.
PJM200918PJM DOCs #
BAAL Field Trial
The purpose of the new BAAL standard is to maintain interconnection frequency within a predefined frequency profile under all conditions (normal and abnormal), to
prevent frequency-related instability, unplanned tripping of load or generation, or
uncontrolled separation or cascading outages that adversely impact the reliability of
the interconnection.
NERC required the balancing authority demonstrate real-time monitoring of ACE and interconnection frequency
against associated limits and
shall balance its resources and
demands in real-time so that its
ACE does not exceed the
BAALs for a time greater than
30 minutes.
PJM200919PJM DOCs #
BAL 003 Requirements
R1- Review and recalculate the Frequency Response of the Balancing Authority Area.
R2- Establish and maintain a Frequency Bias Setting that is close or greater than the Balancing Authoritys Frequency Response.
R3 - Operate its Automatic Generation Control (AGC) on Tie Line Frequency Bias.
R4- Use Dynamic Scheduling or Pseudo-ties for jointly owned units that reflect their respective share of the unit governor droop response in their respective Frequency Bias
Setting.
R5- Balancing Authorities that serve native load shall have a monthly average Frequency Bias Setting that is at least 1% of the Balancing Authoritys estimated yearly peak demand per 0.1 Hz change.
R6 - A Balancing Authority that is performing Overlap Regulation Service shall increase its Frequency Bias Setting to match the frequency response of the entire area being
controlled.
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