You can translate the logged-in message via any translation plugin or using the following filter: pp_login_form_logged_in_message

Please add the following code in your current theme’s functions.php file to change the message using filter:

function powerpack_change_logged_in_msg( $msg, $display_name, $logout_url ) {
	// change the message here.
	$msg = sprintf( 'You are Logged in as %1$s (<a href="%2$s">Logout</a>)', $display_name, $logout_url );

	return $msg;
}
add_filter( 'pp_login_form_logged_in_message', 'powerpack_change_logged_in_msg', 10, 3 );