It is important to first seek the cause of the fraying and its location before moving on to a solution. Most often than not, a broken garage door cable repair exercise requires caution. This is one of those parts that support the entire infrastructure. If it suddenly fails then you could be in lots of trouble. Open the door in order to release the tension which will rapidly accumulate in the other spring.
Alternatively, if you have a manual one then gently release the latch. Check the balance as well because this is the best opportunity to ensure that everything is in order before reassembling. Sometimes it is just a case of a cotter pin or washer that is jammed at the bottom of the door and thus causing enormous strain on the cables. If there is any fraying on the cable then there is no option but replacement with new ones.
Garage Door Repair Rosenberg, 281-375-3134, Southwest Freeway, Rosenberg, Texas, 77469, http://www.garagedoorrepairrosenberg.com/