Hybrid Symbolic-Numeric Framework for Power System Modeling and Analysis

TL;DR

This paper introduces ANDES, an open-source Python library that combines symbolic and numeric methods to simplify power system modeling, enabling rapid development, simulation, and analysis of complex systems with high accuracy.

Contribution

The paper presents a hybrid symbolic-numeric framework and open-source library for power system modeling that automates code generation and supports diverse components, improving efficiency and accuracy.

Findings

ANDES closely matches commercial tools for power flow and eigenvalue analysis.

The framework enables rapid modeling of complex power system components.

Validation confirms high accuracy and efficiency of the proposed method.

Abstract

With the recent proliferation of open-source packages for computing, power system differential-algebraic equation (DAE) modeling and simulation are being revisited to reduce the programming efforts. Existing open-source tools require manual efforts to develop code for numerical equations, sparse Jacobians, and discontinuous components. This paper proposes a hybrid symbolic-numeric framework, exemplified by an open-source Python-based library ANDES, which consists of a symbolic layer for descriptive modeling and a numeric layer for vector-based numerical computation. This method enables the implementation of DAE models by mixing and matching modeling components, through which models are described. In the framework, a rich set of discontinuous components and standard transfer function blocks are provided besides essential modeling elements for rapid modeling. ANDES can automatically generate robust and fast numerical simulation code, as well as and high-quality documentation. Case studies present a) two implementations of turbine governor model TGOV1, b) power flow computation time break down for MATPOWER systems, c) validation of time-domain simulation with commercial software using three test systems with a variety of models, and d) the full eigenvalue analysis for Kundur's system. Validation shows that ANDES closely matches the commercial tool DSATools for power flow, time-domain simulation, and eigenvalue analysis.