My score is 82.75 All india rank - 18898 SC category- 575 Any chance?

Hey.
As per the Previous year trends, if your rank is around 18898 and you belong to the SC category  your changes for admission in any of the National Law Universities is not much.
In the previous year the last year to get admission in any of the NLU was a rank around 12573. Keep in mind that the cut off varies each year due to several factors like level of Competition etc and it might differ this year too. But still your  chances are too less. You can use the link below to check previous year trends.
https://law.careers360.com/articles/clat-marks-vs-rank
Best of luck