[Advanced] MATLAB_Simulink Power System Modeling and Simulation

# 1. Basics of MATLAB/Simulink Power System Modeling**

Power system modeling involves the use of mathematical models and computer simulation techniques to simulate the behavior of power systems. MATLAB/Simulink is a powerful software platform that can be used for power system modeling and simulation.

Basics of MATLAB/Simulink power system modeling include:

* Power system network topology: A power system network consists of nodes (such as substations, power plants, etc.) and lines that connect these nodes. MATLAB/Simulink provides various tools to create and analyze power system network topologies.
* Power system component modeling: Power system components include transformers, lines, generators, and loads. MATLAB/Simulink offers a rich library of components that can be used to create and simulate power system components.

# 2. Power System Modeling Theory and Practice

### 2.1 Principles of Power System Modeling

#### 2.1.1 Power System Network Topology

Power system network topology describes the interconnection between various components in a power system, ***mon power system network topologies include:

- **Radial Network:** Radiates from a single source node to multiple load nodes in a star-like structure without forming loops.
- **Ring Network:** Composed of multiple nodes and lines connecting these nodes to form a closed loop, offering higher reliability.
- **Mesh Network:** Formed by multiple nodes and lines interconnecting to create a complex network structure, providing strong redundancy.

#### 2.1.2 Power System Component Modeling

Power system component modeling is the process of abstracting the electrical characteristics of various components (such as generators, transformers, lines) ***mon power system component models include:

- **Generator Model:** Describes the electromagnetic and mechanical characteristics of generators, including synchronous and asynchronous generator models.
- **Transformer Model:** Describes the transformation ratio, leakage reactance, and losses of transformers, including ideal and practical transformer models.
- **Line Model:** Describes the resistance, inductance, and capacitance of lines, including lumped parameter and distributed parameter models.

### 2.2 Power System Simulation Techniques

#### 2.2.1 Simulation Methods and Tools

Power system simulation techniques involve the use of computers to simulate the operation process of power systems, ***mon power system simulation methods include:

- **Time-domain Simulation:** Directly solves the differential equations of the power system, simulating the time-varying process of the power system.
- **Frequency-domain Simulation:** Transforms the differential equations of the power ***

***mon power system simulation tools include:

- **MATLAB/Simulink:** A widely used platform for power system modeling and simulation, offering a rich library of power system components and simulation algorithms.
- **PSCAD/EMTDC:** A software specifically designed for transient simulation and transient stability analysis of power systems.
- **PowerFactory:** A comprehensive power system simulation and analysis software covering steady-state, transient, and dynamic simulation.

#### 2.2.2 Validation and Calibration of Simulation Models

Validation and calibration of simulation models are crucial steps to ensure the accuracy and reliability of simulation results. Validation checks if the simulation model correctly reflects the structure and characteristics of the actual power system, while calibration adjusts the parameters of the simulation model to align its results with actual measurement data.

Methods for validation and calibration include:

- **Structural Validation:** Checks if the network topology, component parameters, and interconnection relationships of the simulation model match the actual power system.
- **Data Validation:** Compares simulation results with actual measurement data to analyze the accuracy and reliability of the simulation model.
- **Parameter Calibration:** Adjusts the parameters of components in the simulation model to make the simulation results as close as possible to the actual measurement data.

# 3.1 Power System Steady-State Analysis

Steady-state analysis is an important aspect of power system modeling, used to analyze the behavior of the system under stable operating conditions. Steady-state analysis mainly includes load flow calculation and short-circuit calculation.

#### 3.1.1 Load Flow Calculation

Load flow calculation is the process of determining the magnitude and phase angle of voltage and current at each node in a power system under stable operating conditions. The purpose of load flow calculation is to provide a basis for power system planning, operation, and control.

In MATLAB/Simulink, the `powerflow` function can be used for load flow calculation. The `powerflow` function requires input of system network topology, component parameters, and load data. The function outputs include voltage, current, and power flow at each node.

% Power system network topology
network = struct('nodes', [1, 2, 3,