Section 155 of the Spanish Constitution
- If a Self-governing Community does not fulfil the obligations imposed upon it by the Constitution or other laws, or acts in a way that is seriously prejudicial to the general interest of Spain, the Government, after having lodged a complaint with the President of the Self-governing Community and failed to receive satisfaction therefore, may, following approval granted by the overall majority of the Senate, take all measures necessary to compel the Community to meet said obligations, or to protect the above-mentioned general interest.
- With a view to implementing the measures provided for in the foregoing paragraph, the Government may issue instructions to all the authorities of the Self-governing Communities.
This is a copy of a similar Section of the German Constitution.
It has a deliberate open redaction because it is intended to be used in very extreme situations.
According to several Constitutionalists experts in Spain, it is very doubtful that this Section can be used to invoke a single new election in Catalonia.
The redaction allows the Government of Spain to take temporary control of several aspects of any Autonomous Community. It is not possible to suspend an Autonomous Community with this section or with any section of the Spanish Constitution, so the answer shoud be "No", Rajoy cannot repeat elections in Catalonia as much as he can.
It is even under discussion if Section 155 enables him to convoke elections once in Catalonia.
Hope you find this answer of interest.