Development of Power System Dynamic Security Analysis Tools Based on the Most Current Snapshot from SCADA Data
No Thumbnail Available
Date
2025-05
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
Currently power systems become increasingly complex, driven by the continuous increasing load demands and growing interconnection of stochastic generations. Furthermore, the introduction of demand response mechanisms to balance generation and consumption is under active investigation. These developments make system operating conditions less predictable, leading to significant challenges in ensuring operational security. To address these challenges, both static and dynamic security analysis tools are essential. However, until recently, efforts in security analysis have predominantly emphasized static methods. The focuses of this thesis is to develop effective and robust tools and techniques for dynamic security analysis in near real-time environments.
One of the core elements of near real-time dynamic security assessment tools is contingency screening and ranking. Fast power system contingency screening and ranking technique has been developed in this thesis, and its performance is evaluated using benchmark test cases. The approach analyzes the transient stability of the power system against a specified list of credible contingencies. Based on the most current snapshot from Supervisory Control and Data Accusation (SCADA) data transient stability is simulated for each credible contingency and Transient Stability Index (TSI) is evaluated as the normalized weighted sum of squares of error at every simulation time step based on both machine’s state variables such as rotor angle deviations, rotor angular speed, etc and machine’s bus complex bus voltages (magnitude V and angle θ). Finally contingencies are ranked based on these TSI and the worst contingency is identified for the next detail assessment. This proposed method not only reduces the time performances but also improves the accuracy of resulting indices. The method is tested on IEEE 9bus and 11bus test systems. Test results reveal that the proposed method is faster, robust and can be used in near real-time dynamic security assessment tools. .
Determining if all synchronous generators remain in synchronism after subjected to large disturbance is significantly important to maintain power system transiently stable. To achieve this requirement, the transient stability assessment tool that estimate the systems distance to transient stability boundary for the contingency under consideration is required. In this thesis critical clearing time (CCT) is used to estimate the distance at a given particular operating point from transient stability boundary. Using the proposed contingency screening and ranking technique the worst contingency is identified based on their TSI. Then critical clearing time (CCT) is evaluated for this contingency to represent the systems distance to transient stability boundary. CCT is normally calculated by uniformly increasing the fault clearing time until the system instability using traditional PTDS. A novel transient stability assessment (TSA) tool that avoids the time-consume due to the repetitive step increase fault duration and high computational burden resulting from using traditional numerical integration method and classical differential transformation method is developed and introduced in this thesis. This tool combines PTDS based on Adaptive step-size Differential Transformation Method (AsDTM) by cross cut technique to evaluate CCT for the worst contingency. Its performance efficiency and accuracy is assessed and validated using two standard test cases.
Effective dynamic security analysis (DSA) tools can identify harmful or insecure operating conditions and recommend preventive control actions to restore stability and security within the system. Fast and robust tools that check and enhance power system dynamic performance based on combined power system time domain simulation (PTDS) and particle swarm optimization (PSO) is proposed here. The method aims at modifying the operating conditions of a power system so as to make it able to withstand severe contingency that would drive it to instability. Conventional time domain simulation method requires high computational efforts however, to support control room operators in taking preventive measures required within timeframe, time domain simulation with improved performance efficiency is needed. A novel power system time domain simulation method which is based on adaptive order and step-size differential transformation (AOSDTM) with significantly better performance efficiency is proposed. The worst contingency is identified based on the proposed contingency screening and ranking technique. Transient stability criteria are checked for this worst contingency by the system operators maintaining system constraints. The critical fault clearing time is used as key feature for monitoring power system transient stability during generation rescheduling process. The proposed and developed tools are tested and validated by using standard IEEE test systems. The test results show that the proposed method is fast and robust and can be used in a near real time power system DSA tools
Description
Keywords
Dynamic security analysis, Time domain simulation, Transient stability assessment, Contingency screening, Differential transformation method, Preventive control