After the upward revaluation at end of Year 1, you have added $200 to Asset X and $200 to Revaluation Surplus.
In Year 2 and Year 3, you are moving the excess depreciation from Revaluation Surplus on the Balance Sheet to Retained Earnings on the Balance Sheet, $100 per year, so at the end of year 3, you can the $200 in Retained Earnings and $0 in Revaluation Surplus.