I am a regular visitor to this site. I have been voting good questions from long time.
I have cast 600 votes & earned
electorate badge as well. But my profile page shows total votes as
Votes are occasionally reversed due to detection of anomalous voting patterns by the automated SE system (at 0300 UTC daily). This explains the discrepancy between your total votes cast (600) and the total you now see (594). See, on Meta.Stackexchange:
That post is written from the perspective of a person who receives serial votes and sees reputation points reversed on their account, but the same applies to the person who gives serial votes and sees the total vote count decrease. In your case, you may have been legitimately voting on good posts, but because the pattern of your voting appeared to be directed toward one or more specific user(s), the system identified this as grounds for reversal.
Vote reversals do not affect your ability to vote going forward or your own reputation. Please do remember to weigh posts based on the quality of their content prior to voting.