The transmission facilities that we are proposing based on this Assessment are listed in Tables PR-2 through PR-22, and shown graphically by zone in Figures PR-1 through PR-5. Changes that have occurred since the 2008 Assessment are listed in Table PR-23. Please also refer to our Asset Renewal section for a list of our larger asset renewal projects.
In each of these tables, there is a column indicating the planned in-service year for each particular facility and a column indicating the year the facility is needed. Sometimes the year that facilities are needed precedes the planned in-service year. There are a variety of reasons for this, including:
- The preferred alternative to address a particular need may take several years to implement.
- The need had been addressed with operating procedures that are becoming less effective or ineffective, necessitating a permanent solution.
- The preferred alternative to address a particular need may need to be implemented in phases, thus delaying completion of the entire project.
- New data or information affected the nature of the need or limitation, necessitating a change in the preferred alternative and introducing a delay in implementation.
- The need for a project was based on load or generation development that was uncertain.
- Stakeholder input necessitated a change in the alternative to be implemented, introducing a delay in implementation.
Tables PR-2 through PR-12 show the facilities planned by year for 2009-2019. Table PR-13 shows provisional facilities where the in-service date is yet to be determined or beyond the 2019 timeframe.
Tables PR-14 through PR-18 show the facilities planned by zone.
Table PR-19 provides a list of planned transmission lines involving new right-of-way for 2009-2024. Since ATC intends to solicit public input on the identification of ultimate solutions through its public planning process, these particular projects may be modified in the future.
Table PR-20 provides a list of proposed transmission line rebuilds, line reconductoring and uprates on existing right-of-way.
Table PR-21 provides a list of proposed new substations and transformer additions (excluding transmission-to-distribution transformers).
Table PR-22 provides a list of other proposed substation equipment additions or replacements.
Need categories
Within these tables, the need for each project is identified. Need categories include the following:
Reliability |
Facility (line, transformer, substation equipment) normal rating is exceeded under system normal conditions or emergency rating is exceeded under single contingency conditions, or bus voltage is not within 5 percent of nominal voltage under normal system conditions or is not within 10 percent of nominal voltage under single or multiple contingency conditions, or the contingency creates a cascading outage risk (see Planning criteria). Impending overload or voltage violations are noted as appropriate . |
New generation |
In our generation interconnection studies and related transmission service studies, the facility has been identified as necessary to accommodate new generation. |
T-D interconnection |
Facility is required to interconnect to a new transmission- distribution substation needed by a distribution company served by ATC . |
Asset renewal |
We have identified the facility as needing repair or replacement. |
Stability |
We have identified the facility as needed to ensure that our dynamic stability criteria are met (see Planning criteria) , or to improve stability response of generation. |
Economics |
Preliminary and partial list of projects emerging from our economic planning studies that may be beneficial to reducing congestion, enhancing system transfer capability and producing economic benefit. |
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Planning criteria & tools