Northeast Utilities reported that of 63,000 customers who had lost power during the day, 33,400 were still without electricity late last night.
Officials at Northeast Utilities said the problem was likely to take all night to fix.
Northeast Utilities reported that thousands of customers lost power and had it restored throughout the week.
Northeast Utilities has also started training programs for managers.
Northeast Utilities estimates total coverage of its stranded costs at $3 billion.
Northeast Utilities spent $8.5 million on tree trimming last year.
The test facing the power company here, Northeast Utilities, is a new one for the nuclear industry.
Northeast Utilities had fought to bring the plant back on line after a long shutdown for safety issues.
Northeast Utilities is not planning any new plant construction, and the two sides have agreed to see how many customers sign up.
Northeast Utilities was given the draft of the state report last month to review.
