TRANSMISSION ALTERNATIVES CONSIDERED

Transcription

1 EB-00-0 Tab Page of TRANSMISSION ALTERNATIVES CONSIDERED In determining the proposed facilities, Hydro One and the West GTA LDCs investigated six options to address the two needs identified in this Application at, Tab, Schedule. The Do Nothing approach was also considered however this approach would aggravate the two needs and was therefore not carried forward in the assessment. After an initial investigation, four of the six options were not considered further since they: 0 (a) placed too much load on circuits VR/VR (Option T) and TB/TB (Option T); or (b) did not meet one of the primary needs (Option T); or (c) were not feasible due to space constraints (Option T). Details of the four eliminated options maybe found in the joint planning study filed at, Tab, Schedule. 0 Two of the six options that were technically feasible and comparable in cost are described and further analyzed below: Option T: Circuits VR/VR Extension and Hurontario Switching Station (SS) Circuits VR and VR are extended from Cardiff west to the Pleasant tap (approximately. km in length). A new SS is constructed at this junction, called Hurontario SS. Jim Yarrow M is radially re-supplied from the new SS (see Figure ). This effectively provides a second source of power for the Pleasant Tap, off-loading circuits RT and RT from Erindale Junction to Hanlon Junction and from Hanlon

2 EB-00-0 Tab Page of Junction to Jim Yarrow Junction which addresses the Thermal overload guideline. The new SS satisfies the 00 MW guideline by creating an isolation point on circuits RT and RT. Figure : Option T - Circuits VR/VR Extension and Hurontario SS Pleasant RT RT Jim Yarrow M Cardiff Goreway Bramalea VR VR VR VR VRP Claireville Hurontario SS. km VR VR Trafalgar RT RT RT RT Hanlan JCT Richview Erindale Tomken Option T: Circuits TB/TB Extension and Hurontario SS 0 Circuits TB and TB are extended from Meadowvale east to the Pleasant Tap (approximately km). A new SS is constructed at this junction, Hurontario SS, and Jim Yarrow M is radially re-supplied from the new SS. Technically this option performed adequately although not as well as Option T because the voltages in Option T were not quite as high as those in Option T which is indicative of an inherently weaker system.

3 EB-00-0 Tab Page of Figure : Option T - Hurontario SS and TB/TB extensions from Meadowvale Pleasant RT RT Claireville Jim Yarrow M Cardiff Goreway Bramalea VR VR VR VR VRP VR Meadowvale.km VR Halton Hurontario SS Trafalgar DESN TB TT TB TB RT RT RT RT Hanlan JCT Burlington Palermo Trafalgar Erindale Tomken Richview Recommended Option and Rationale 0 The two needs as identified in, Tab, Schedule can be addressed by either Option T or T by adding a new SS and creating an isolation point on circuits RT and RT. These options reinforce the transmission system to limit load loss to 00 MW for an outage of a double-circuit line and provide relief for the existing 0 kv circuits RT/RT out of Trafalgar. The Hurontario SS will also provide additional capability for future east-west transmission line expansions to increase transfer capability into the Toronto area, from the west, and to accommodate further load growth in GTA West beyond the next ten year horizon.

4 EB-00-0 Tab Page of Both Options T and T are technically feasible and satisfy the two needs. However since the extension of circuits TB and TB in Option T is approximately. km longer ( km vs.. km) than the extension of circuits VR and VR, Option T would be approximately $0 million more costly than Option T. Hence, Option T was selected over Option T. 0 The proposed facilities in this Application also contribute, in part, to relieving overloading along the section of the Pleasant Tap south of Hurontario SS. Subsequent projects will be proposed in future applications to address the remaining sections of the Pleasant Tap. Sub-options for Recommended Option In Spring 00, following the joint study the preferred option, Option T, was further assessed and two sub-options were identified: 0 Option (a): Hurontario SS consisting of in-line breakers together with the extension of VR and VR from Hurontario SS to Cardiff ; and, Option (b): Hurontario SS consisting of circuit breakers with full switching of all present and future transmission circuits, together with the extension of VR and VR from Hurontario SS to Cardiff. Option (b) was found to be significantly more expensive compared to Option (a), costing $M vs. $M. This additional cost was not deemed to provide sufficient incremental benefit; therefore Option (a) is recommended. The incremental revenue benefits are the same for all options. The least cost option has been selected. Further details can be found by reviewing the discounted cash flow and

5 EB-00-0 Tab Page of rate impact assessment for the recommended option which may be found in, Tab, Schedule. The Ontario Power Authority supports Option (a) as the solution that addresses the need as soon as possible, as explained in their letter of endorsement in, Tab, Schedule.