A recurring issue when studying agent-based algorithms and strategies for Power Microgrid Systems is having to construct an interface between the agent domain and the electrical model domain being simulated. Many different tools exist for such simulations, each with its own special external interface. Although many interfacing efforts have been published before, many of them support only special cases, while others are too complex and require a long learning curve to be used for even simple scenarios. This work presents a simple programming application interface (API) that aims to provide programming access to the electrical system model for any real-time simulation tool, from any agent-based platform, or programming language. The simplicity of the interface stems from the assumption that the simulation happens in real-time and the agent domain is not being simulated. We propose four basic operations for the API: read, write, call, and subscribe/call-back. We tested these by supporting two examples. In one of the examples, we present a creative way to have the model access libraries that are not available in the simulated environment.