You need to connect to DGMGRL and explicitly set the apply state to APPLY-OFF for the standby database. 

DGMGRL> CONNECT sys/password@standby_connect_identifier AS SYSDBA;

Following command run by using STANDBY:

Stop the MRP by setting the database’s state:

DGMGRL> EDIT DATABASE <standby_unique_name> SET STATE='APPLY-OFF';

Start the MRP by Setting the Database State:

DGMGRL> EDIT DATABASE <standby_unique_name> SET STATE='APPLY-ON';

Example:

DGMGRL> EDIT DATABASE standby SET STATE='APPLY-OFF';
Succeeded.

DGMGRL> EDIT DATABASE standby SET STATE='APPLY-ON';
Succeeded.