Why Is the Canny Edge Detection Used Instead of Sobel / Prewitt Edge Detection Before Hough Transformation?
Canny Edge Detection is considered to be a better (In False Alarm sense) edge detection than those you mentioned.
This is, mainly, due to 2 steps:


Non Maximum Suppression - Edges candidates which are not dominant in their neighborhood aren't considered to be edges.
Hysteresis Process - While moving along the candidates, given a candidate which is in the neighborhood of an edge the threshold is lower.


Those 2 steps reduce the number of "False" edges and hence create a better starting point for farther process like Hough Transformation.