National Grid said it is implementing a short- and long-term plan to avert the extended power outages that have frustrated Foxborough residents over the past 13 months. In a YouTube video, National Grid vice president Marie Jordan said the company is addressing problems highlighted by three major storms, starting with an October 2011 snowstorm that left the town in darkness for days. Among other fixes, National Grid said it will increase the size of wires and build new connections for Foxborough in the Union Loop, a 12-tiered power delivery system that also serves surrounding towns. Work on existing wood poles will take one to four years, officials said, and installation of the town’s new power source in the Loop is expected to take up to eight years to complete. Selectmen met with National Grid president Marcy Reed in November to share concerns and get answers, and asked the company to make a video to keep residents up to date with progress.