Document Type

Theses, Ph.D

Disciplines

Environmental sciences, 2. ENGINEERING AND TECHNOLOGY, 2.2 ELECTRICAL, ELECTRONIC, INFORMATION ENGINEERING

Publication Details

A thesis presented for the degree of Doctor of Philosophy School of Electrical and Electronic Engineering Technological University Dublin May 21, 2025 Under the supervision of Prof. Michael Conlon.

Abstract

Renewable energy targets have resulted in high penetration of non-synchronous generation and consequently reducing power system inertia, and this could lead to power system frequency instability following a disturbance, such as the loss of generation. A concern to power system operators is the rate of change of frequency (ROCOF) following the loss of generation. Fast ROCOF presents many challenges for power systems but the primary concern is that fast ROCOF reduces the time-frame that primary frequency control has to arrest a frequency decline following the loss of generation. Therefore, power system operators need to develop strategies to operate power systems with high instantaneous penetrations of non-synchronous generation, reduced inertia and that are resilient to fast ROCOF. The focus of this research is on power system ROCOF following the loss of a synchronous generator in multi-bus networks.

Conventional methods used to estimate potential power system ROCOF and minimum inertia requirements often assume a single-bus network and constant power loads. Hence, the impact of lost reactive power, changes to individual bus voltages and load response are neglected. These assumptions often result in an over-estimated potential ROCOF and therefore surplus inertia requirements.

This research presents a detailed multi-bus ROCOF analysis of a power system following the loss of a synchronous generator. It investigates the most influential factors on ROCOF, such as the impact of lost active and reactive power, inertia distribution and load response on system ROCOF. Furthermore, this research has developed a novel method of estimating the potential ROCOF for the loss of a particular generator that, unlike conventional methods, also takes account of lost reactive power and the subsequent load response. It is shown that these two factors can have a significant impact on the speed of ROCOF and by taking both factors into account, a more accurate estimate of the potential ROCOF is possible. This will allow power system operators to more accurately estimate the potential ROCOF for the loss of a particular generator and confidently reduce system inertia and increase the instantaneous renewable generation.

DOI

https://doi.org/10.21427/tbvy-mt88

Creative Commons License

Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License
This work is licensed under a Creative Commons Attribution-NonCommercial-Share Alike 4.0 International License.

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