IESO Expedited System Impact Assessment
T1 Replacement at Richmond South DS
2014-EX720
Final Report
Summary
Conditional Approval for Connection
Hydro Ottawa Ltd. (the “connection applicant”) is proposing to replace T1 at Richmond South DS with a
replacement unit due to failure (“the project”). The connection applicant will install the failed unit that
was removed under expedited SIA report 2012-EX601. This transformer will be operated without the
under load tap changer (ULTC).
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.
Requirements
The connection applicant shall satisfy all applicable requirements and standards specified in the Market
Rules and the Transmission System Code. The following requirements summarize some of the general
requirements that are applicable to the proposed project.
1. The connection applicant shall ensure that the 115 kV equipment is capable of continuously
operating between 113 kV and 127 kV, as specified in Appendix 4.1 of the Market Rules. Protective
relaying must be set to ensure that transmission equipment remains in-service for voltages up to 5%
above the maximum continuous value.
2. If revenue metering equipment is being installed as part of this project, the connection applicant
should be aware that revenue metering installations must comply with Chapter 6 of the IESO Market
Rules. For more details the connection applicant is encouraged to seek advice from their Metering
Service Provider (MSP) or from the IESO metering group
3. The connection applicant must complete the IESO Facility Registration/Market Entry process for the
project in a timely manner before the IESO final approval for connection is granted.
Final Report
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T1 Replacement at Richmond South DS
2014-EX720
1 Project Description
The applicant is proposing to replace T1 at Richmond South DS with a new unit due to failure. The
connection applicant will install the failed unit that was removed under expedited SIA report 2012EX601. This transformer will be operated without the under load tap changer (ULTC). Richmond South
DS is connected to the 115 kV circuit S7M and C7BM.
The expected in-service date for the replacement transformer is June 18, 2014.
The technical specifications of the existing and replacement transformers are given in Table 1.
Richmond South DS
All values for replacement equipment are specified at the time of order. Actual values to be provided prior to inservice dates.
Transformer
Failed T1
Replacement T1
Configuration
Transformation (kV)
Winding Configuration
Impedance to Ground
Three phase
110.0/8.32
Three phase
110.0/8.32
Delta/Wye
HV – ungrounded
LV – solidly grounded
Delta/Wye
HV – ungrounded
LV – solidly grounded
Thermal Rating
Continuous Thermal Rating
6.0 MVA ONAN
6.0 MVA ONAN
10.0 MVA
6.0 MVA
10-DAY Thermal Rating
15-MIN Thermal Rating
Positive Sequence Impedance
(H-L)
Under-load tap-changer
Off-load tap-changer
In Service OLTC position
Not applicable. The transformer will be off loaded if required.
R = not known
X = 8.95%
on 6 MVA base
R = not known
X = 8.5%
on 6 MVA base
LV ± 10%, 16 steps
Tap 1: 118.25 kV
Tap 2: 115.5 kV
Tap 3: 112.75 kV
Tap 4: 110.0 kV
Tap 5: 107.25 kV
Tap 2: 115.5 kV
Not operable
Tap 1: 118.25 kV
Tap 2: 115.5 kV
Tap 3: 112.75 kV
Tap 4: 110.0 kV
Tap 5: 107.25 kV
To be advised
Table 1 – Comparison of Transformer Parameters at Richmond South DS
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T1 Replacement at Richmond South DS
2014-EX720
2 Assessments
See the expedited SIA report 2012-EX601 for an assessment of load peaks and load projects and load
angle assessment.
The continuous rating of the replacement transformer is 6.0 MVA and therefore, there is a deficiency
when compared to the 2012 peak load of 7.1 MVA. Hydro Ottawa Ltd. has advised that they would
allow the transformer to be loaded slightly higher until they were able to off load to another
transformer.
2.1
Conclusions
It can be concluded that the replacement of T2 at Richmond South DS with a new transformer will not
result in a material adverse impact on the reliability of the IESO-controlled grid provided that all
requirements in this report are met.
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