Guidelines for use of real-code in EMT models for HVDC, FACTs and inverter based generators in power systems analysis

Introduction

This Technical Brochure summarizes work done in a Joint Working Group between CIGRE B4.82 (Guidelines For Use Of Real-Code In EMT Models For HVDC, FACTS and Inverter Based Generators In Power Systems Analysis) and IEEE (Use of Real-Code in EMT Models for Power System Analysis, a working group under the Transient Analysis and Simulation task force). This group has over 100 members from IEEE and CIGRE, including users, simulation tool developers, manufacturers and others.

The objective is to create a standard methodology for interfacing of control and protection models to power system simulation tools, including “realcode” (ie the actual source code used in field hardware) and other generic or user-written models.

Scope and Methodology

This method resolves many common problems with models used in power system simulation tools, such as compatibility (due to compiler versions or with different simulation tools), confidentiality concerns, accuracy and reliability issues.

To resolve these issues, the working group developed a standard format of interfacing controller code to power system simulation programs – this is called the IEEE/CIGRE DLL Modeling Method.

The method is used to develop simulation models, released in MS Windows DLL format (but also in other formats such as .so shared object files for Linux). The model is self-documenting, and contains functions that can be called (by model import tools from simulation program developers) to document the inputs, outputs, parameters, sample time, state variable requirements (and other important aspects of the model).

The CIGRE B4.82 Technical Brochure

The CIGRE B4.82 Technical Brochure is organized into the following chapters:

1. Introduction
2. General Principle and Benefits – overview and advantages of the method.
3. Specification of the IEEE/Cigre DLL Method V1.1 – documents the method routines, data structures and usage cases.
4. State Variables – a description of state variables and how they should be handled in models and in this method
5. Guidelines for Model Writers – application specific information intended for model writers (which can be manufacturers who have control and protection code already written, or generic model writers etc.).
6. Guidelines for End Users –guidelines for the end users of the models, including steps to use the models in their simulation tools.
7. Simulation Tool Developer Manual – important factors for power system simulation tool developers to import and create interface tools for use by end users.
8. Next Steps and Future Work – a tracked list of ideas/suggestions for consideration in future revisions of the method.
9. Conclusion

Conclusions

The deliverables of this working group include:

• The method definition .h header files (defining the format of signals used in the interface and subroutines called, example cases).
• Example source code and wrappers for simple controller models.
• A manual (with chapters targeted at model writers, simulation tool developers, and end users of the model).

The IEEE/CIGRE DLL Modeling Method has been successfully applied to numerous power system simulation tools and has been used by many manufacturers of power system controllers. It is also supported by other HVDC Working Groups (such as InterOpera) and simulation tools (both EMT and RMS/transient stability tools).

The manual is released by IEEE, as well as in a CIGRE Technical Brochure.