You can parse the exception out of XML log. Or simply, just check WinSCP exit code.
See https://winscp.net/eng/docs/guide_automation#results

How can I use script to separate normal log information and Exception log information?

I write following command into a bat file(windows):

winscp /script=qwer.txt /log=log4qwer.txt /xmllog=log4qwer.xml

After running this bat, I can get a log file named log4qwer.txt, but in this file, I can see very detail log information. But sometimes I just care about , are there any Exception during the running of the FTP client?

Can I use some paramter in the bat file or script file to separate normal log information and Exception log information, or output the Exception log information to a specified path alone?