IESO Expedited System Impact Assessment
TA-OTTAWA GT CONTROLS UPGRADE AND STG STATOR REPLACEMENT
2014-EX705
FINAL REPORT
Executive Summary
Conditional Approval for Connection
TransAlta Cogeneration LP (the “connection applicant”) is proposing to replace the governor on gas turbine
generator G1 and the stator on steam turbine generator G2 at the Ottawa Health and Sciences Centre (OHSC)
CGS.
This assessment concluded that the proposed changes are expected to have no material adverse impact on
the reliability of the IESO-controlled grid. Therefore, the IESO recommends that a Notification of Conditional
Approval for Connection be issued for the proposed project, subject to implementation of the requirements
outlined in this report.
Specific Requirements
(1) The connection applicant is required to ensure that the performance of the new governor installed on G1
meets the requirements identified in item 1 in the General Requirements. The data provided for this
assessment indicates that this performance will be achieved.
(2) The connection applicant is required to ensure the generator modelling parameters for G2 do not
significantly change with the stator replacement.
General Requirements
The connection applicant shall satisfy all applicable requirements and standards specified in the Market Rules.
The following requirements summarize some of the general requirements that are applicable to the proposed
project.
(1)
Generator G1 shall regulate speed with an average droop based on maximum active power adjustable
between 3 - 7% and set at 4%. Regulation dead band shall not be wider than ± 0.06%. Speed shall be
controlled in a stable fashion in both interconnected and island operation. A sustained 10% change of
rated active power after 10 s in response to a constant rate of change of speed of 0.1%/s during
interconnected operation shall be achievable.
(2)
The connection applicant must initiate and complete the IESO Market Entry/Facility Registration process
for the project in a timely manner before the IESO final approval for connection is granted.
As soon as the commissioning tests are completed and the actual data is available, the connection
applicant is required to provide updated parameters and models for the completed changes. If the
actual data differ materially from the data that is used in the report or if the data for the generator
model of G2 changes significantly, then further analysis may need to be performed by the IESO before
final approval to connect is granted.
Final Report
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TA-Ottawa GT Controls Upgrade and STG stator replacement
2014-EX705
1. Project Description
The OHSC CGS facility consists of a gas turbine generator G1 with a rating of 57.4 MVA, and a steam turbine
generator G2 with a rating of 35.3 MVA. The connection applicant is proposing to replace the governor for G1
and the stator for G2.
The governor on G1 will be replaced because vendor support is no longer available for the existing one. The
existing and new governors are both supplied by Woodward. In summary, this will be a “like-for-like” governor
replacement project.
The stator on G2 will be replaced as the insulation has been deteriorating over the years. The replacement
stator is the same size and rating as the existing one. The existing and new stators are both supplied by Brush.
This will also be a “like-for-like” stator replacement project.
The in-service date of the replacements is in May 2014.
2. Equipment Model and Data
2.1 G1 Governor Model
The new governor for G1 can be modelled by a GGOV1 model as shown in Figure 1. The new parameters are
given in Table 1.
Figure 1: Governor Model Block Diagram (GGOV1)
Final Report
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TA-Ottawa GT Controls Upgrade and STG stator replacement
2014-EX705
Table 1: Governor Model Parameters
CONs
Value
J
0.04
J+1
1
J+2
0.023
MaxERR
J+3
-0.023
MinERR
J+4
2.4
KPGOV
J+5
1.1
KIGOV
J+6
0
KDGOV
J+7
1
TDGOV
J+8
1
VMAX
J+9
0.24
VMIN
J+10
0.4
TACT
J+11
2.7
KTURB
J+12
0.26
WFNL
J+13
0.1
TB
J+14
0
TC
J+15
0
TENG
J+16
0.3
TFLOAD
J+17
1
KPLOAD
J+18
3.3
KILOAD
J+19
1
LDREF
J+20
0
DM
J+21
99
ROPEN
J+22
-99
RCLOSE
J+23
0
KIMW
J+24
99
ASET
J+25
10
KA
J+26
0.1
TA
J+27
99
TRATE
J+28
0
DB
J+29
1
TSA
J+30
1
TSB
J+31
99
RUP
J+32
-99
RDOWN
Final Report
Description
R
TPELEC
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TA-Ottawa GT Controls Upgrade and STG stator replacement
2014-EX705
ICONs Value Description
RSELECT, Feedback signal for governor
droop:
1 electrical power
M
1
0 none (isochronous governor)
-1 fuel valve stroke (true stroke)
-2 governor output (requested
stroke)
Flag Switch for fuel source
characteristic:
M+1
0
0 fuel flow independent of speed
1 fuel flow proportional to speed
2.2 G2 Generator Model
The existing generator parameters for G2 are given in Table 2.
Table 2: Generator Model Parameters
Description
d-axis OC Transient Time Constant
d-axis OC sub-transient Time Constant
q-axis OC Transient Time Constant
q-axis OC sub-transient Time Constant
Inertia
Damping
d-axis Synchronous Reactance
q-axis Synchronous Reactance
d-axis Transient Reactance
q-axis Transient Reactance
Subtransient Reactance
Leakage Reactance
Saturation Factor at 1.0 pu Et
Saturation Factor at 1.2 pu Et
Parameter
T’do (>0)
T’’do (>0)
T’qo (>0)
T”qo (>0)
H
D
Xd
Xq
X’d
X’q
X’’d=X’’q
XI
S(1.0)
S(1.2)
Value
11.4
0.06
4.00
0.06
3.00
0
2.25
2.04
0.20
0.24
0.118
0.10
0.05
0.40
3. ASSESSMENTS
Since G2 replacement is for the stator no assessment is required and performed.
3.1
Generator G1
Appendix 4.2 of the Market Rules requires that the governors must regulate speed with an average droop
based on maximum active power adjustable between 3 - 7% and set at 4% unless otherwise specified by the
IESO. Regulation deadband shall not be wider than +/- 0.06%. Speed shall be controlled in a stable fashion in
both interconnected and island operation. A sustained 10% change of rated active power after 10s in response
to a change of speed of 0.1%/s during interconnected operation shall be achievable.
Governor Stability Test during Islanding Operation
Governor response test was performed in an islanding operation for a step change to the generator output set
point to assess the governor stability as well as the droop characteristic. The generator was initialized to 50%
Final Report
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TA-Ottawa GT Controls Upgrade and STG stator replacement
2014-EX705
of rated generator output. At t=0, the generator output set point was increased by 1% of the full load. To
demonstrate a governor droop of 4%, a speed change of 0.04% is expected.
Figure 2 gives the governor response and shows that the governor response is stable in an islanding operation
and the droop for this governor system is approximately 4%.
Figure 2: Governor Response in Islanding Operation
Governor Stability Test during Interconnected Operation
Governor response test was then performed in an interconnected operation for a step change of system
frequency. The generator was initialized to 50% of rated generator output. At t =10s, the system frequency
was stepped down by 0.1%. To demonstrate a governor droop of 4%, a mechanical output change of 2.5% of
the full load is expected.
Figure shows the response of the proposed governor system which indicates that governor response is stable
in the interconnected operation and the droop for this governor system is approximately 4%.
No intentional speed dead band of this governor is set based on the governor model provided.
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TA-Ottawa GT Controls Upgrade and STG stator replacement
2014-EX705
Figure 3: Governor Response in Interconnected Operation
Change of Speed of 0.1%/s during Interconnected Operation
Governor response tests were also performed in interconnected operation with a 0.1%/s change in system
frequency to assess the speed and magnitude of governor responses. The generator power output was
initialized to 50% of its rated generator output. At t=1s, the system frequency was ramped down or up at a
speed of 0.1%/s for 10s.
Figure and Figure show the generator mechanical power response in response to system frequency decline
and rise, respectively. The simulation results indicate that after the system frequency ramps down or up for 10
s, the proposed governor is capable of providing a sustained 10% change of rated active power. Therefore, the
governor response rate meets the Market Rules’ requirements.
Final Report
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TA-Ottawa GT Controls Upgrade and STG stator replacement
2014-EX705
Figure 4: Generator Mechanical Power in response to System Frequency Decline
Figure 5: Generator Mechanical Power in response to System Frequency Rise
- End of Document -
Final Report
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