Generally speaking, equations in your ETD aren't required to be captioned in the same way that figures and tables are captioned. If you choose to add captions to your equations, they should be consistent for all equations and should follow our instructions for creating a List of Equations. 

Before deciding on the approach you would like to take, be sure to contact the Student Services staff member for your school, as they will be approving your ETD formatting and can weigh-in on what is acceptable.