PROJECTS $500K AND OVER FOR 2014

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1 Page of PROJECTS $00K AND OVER FOR 0 STANDARDIZATION PORTFOLIO Table : Standardization Projects Estimate Estimated Cost Project Title Number ($ Millions) Grounding Compliance Program. Porcelain Insulator Replacement Program 0. Total Cost.

2 Portfolio: Project Title: Project Number: Project Year: 0 Standardization Estimate Cost: $,00,000 Grounding Compliance Program Page of PROJECT DESCRIPTION Objective: The purpose of this project is to rebuild the grounding system of select submersible transformer vaults and pole-mounted transformers across the system, according to THESL currently approved construction standards. This program is required to ensure safe and proper operation of distribution system equipment, thus protecting workers and the public from potentially hazardous step and touch potentials in the event of a fault. 0 Scope: The scope of work for this project is to rebuild the grounding system of about submersible transformer vaults in the former distribution service area of Scarborough and pole-mounted transformers within the downtown core and older system designs. 0 For a submersible transformer vault, each location would require the following: excavation around the vault, driving four ground rods one at each corner, forming a ground loop around the vault and bonding the loop to the existing ground grid inside the vault at two points. Similarly, for a pole-mounted transformer, each location would require the following: installation of a ground rod, upgrading any insufficient wire sizes and connectors, and bonding the transformer case, H ground connection and X terminal (when used as a ground point) separately to the system neutral.

3 Page of DISTRICT(S) DISTRICT NEIGHBOURHOOD STATION(S) FEEDER(S) TORONTO (SUBMERSIBLE), SCARBOROUGH (POLE-MOUNTED) JUSTIFICATION Project Background For submersible vaults, the grounding was investigated and identified to be insufficiently constructed as per current THESL grounding standards. Subsequently, the possibility of step and touch potential has initiated upgrades of the existing grounding to ensure conformance with the Ontario Electrical Safety Code ( OESC ) and THESL construction standards. 0 For pole-mounted transformers, improper grounding has been found where grounding connections were contained within one connector. This is not compliant to THESL currently approved construction standards. Furthermore, the system ground to the ground rod had been compromised, which created insufficient ground path to earth. This has created an initiative to investigate the integrity of THESL pole-mounted transformer grounding systems and rectify any deficiencies. 0

4 Page of Benefits Establishes a sufficiently low resistance path to earth Limits system voltage in fault conditions and ensures fuses and circuit breakers operate properly Increases safety of workers and the public Eliminates any non-conformance to THESL currently approved construction standards and Ontario Regulation /0 0 IMPACT OF DEFERRAL Compliance with grounding requirements is critical, and deferral of this work would increase the risk of step and touch potentials exceeding safe levels for workers and the public. Moreover, deferral of this work would also affect THESL s ability to ensure proper arrester operation, and thus system protection. Proper arrester operation shunts excess current to ground, thereby protecting system assets from potentially damaging levels of energy. This operation also increases public safety by reducing the chances of catastrophic failure of equipment. Lastly, THESL is mandated by Section of Ontario Regulation /0 to ensure that all metal parts of an installation not intended to be energized should be effectively grounded.

5 Portfolio: Project Title: Project Number: Project Year: 0 Standardization Estimate Cost: $0,000 Porcelain Insulators Replacement Program Page of PROJECT DESCRIPTION Objective: The purpose of this project is to replace all existing porcelain insulators with polymer insulators on overhead distribution system. 0 Scope: The scope of work for this project is to replace about 00 porcelain insulators located across all of the former distribution service areas with polymer based materials. THESL will focus on replacing porcelain insulators for the following: worst performing feeders, other areas deemed to be under-performing such as older system configurations, and congested, heavily treed areas where the potential for failure is high and there may be associated public safety risks. The program is intended to supplement the overhead projects where porcelain hardware is being removed. DISTRICTS DISTRICT NEIGHBOURHOOD STATION(S) FEEDER(S) TORONTO, NORTH YORK, SCARBOROUGH, ETOBICOKE, EAST YORK AND YORK JUSTIFICATION Project Background

6 Page of 0 Over the previous decade, porcelain has been phased out for new installations in favour of polymer based materials. Polymeric hardware offers several advantages over porcelain. Porcelain forms water film on the surface that makes flashovers easier to occur, and has to be cleaned, washed and greased for maintenance purposes. Porcelain insulators are also susceptible to fracture and breakages due to their highly fragile properties. Moreover, hairline cracks can also develop in the porcelain that will lead to failure, and these cracks generally can not be seen from the ground. Lastly, porcelain can fail catastrophically, resulting in shards of jagged material being released into high-traffic areas. Subsequently, sharp, damaged porcelain would then pose a safety hazard to workers handling or working on this equipment. Benefits Polymer insulators are compatible with tree-proof conductors that are designed to eliminate outages caused by tree contact, animal contact, short term phase-to-phase and phase-to-ground contact Lower tracking and leakage current would result in lower system losses Polymer insulators have superior mechanical strength, flexibility and not susceptible to fracture Polymer insulators would pose less of a safety concern in the event of a failure 0 IMPACT OF DEFERRAL If this work was to be deferred, it will increase public and worker safety risks as porcelain insulators continue to deteriorate and fail at higher rates. When subjected to lightning or surge voltage stresses, porcelain insulators can puncture and subsequently breakdown completely, not only causing flashover between the energized element and the supporting structure, but may fracture causing porcelain fragmentation in the process. Falling debris, jagged shards, pole fires and environmental risks are also associated with these aging assets. Finally, deferral of this work would also result in THESL losing this window of opportunity to effectively modernize the distribution system.