It is not possible to connect a customized Simscape Component block with the components from the Simscape Power Systems Specialized Technology library. This is because Simscape Component uses .ssc files, which is compatible with the Foundation Library, while components from the Simscape Power Systems Specialized Technology library uses Simulink mathematics underneath. Therefore, connecting these two components is analogous to connecting components from the Simscape Foundation Library to Simulink blocks directly, which is not supported.
If you are using R2015a and newer releases, I would recommend explore the "Customize SPS blocks" feature in the powergui to build more advanced models. The "power_customize" function is the appropriate command for a programmatical approach. For more information, please refer to the following link:
