Abstract
To combat climate change, a large amount of carbon-neutral renewable energy production must be integrated into the power system. The most techno-economically affordable solution to accomplish renewable integration is to increase system intelligence by interfacing communication networks with power systems to form a smart grid. Historically grid automation has been hardwired as earlier wireless technologies lacked the reliability required by protection applications. Fifth generation cellular network (5G) promises to reach low latency and high reliability, suitable for protection communication but needs validation whether promised targets are met in practice. Typically, studies on wireless technologies for smart grid applications are simulations, lacking the accuracy of commercially available wireless networks. Thus, protection communication via 5G is the main focus of this thesis. The aim of this thesis is to investigate whether commercially available 5G is applicable for protection communication. This topic is divided into three sub-research questions discussed in this thesis and the publications. Firstly, prior bottlenecks of wireless technologies for protection communication 5G removes are identified. These include a lack of reliability and low latency, which could be resolved by 5G use cases with associated service portfolios, network slicing, and edge computing. The controller-hardware-in-the-loop (CHIL) results show significant improvement in successfully protected faults with 5G standalone (SA); also, fault clearance times are not as widely spread and slanted towards the lower times. Secondly, the thesis identifies limitations hindering 5G's use in protection communication. These include a small packet size of IEC 61850-based messages compared to the optimal size for 5G and a lack of granularity in the network slicing implementations. Substation communication consists of traffic types with diverse requirements, and adding all the traffic into one slice can increase delays and packet loss in protection communication. Furthermore, edge computing will increase the complexity of protection and collaboration with telecommunication providers requiring applicability to be assessed carefully. Thirdly, the thesis proposes approaches to mitigate the identified limitations. IEC 61850-based packet sizes could be optimised by aggregating packets under the same Ethernet header for wireless transmission. If slicing lacks granularity, protection communication could be prioritised by overall prioritisation of all traffic and adjustment of individual traffic sources. The CHIL results show that prioritisation improves the reliability of protection communication without impacting latency. Additionally, the suitability of edge computing is assessed by a computational study highlighting the bottleneck of total uplink traffic in the urban scenario and the lack of density of devices in the rural scenario.
Translated title of the contribution | Langaton 5G keskijänniteverkon IEC 61850 pohjaisessa suojauskommunikaatiossa |
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Original language | English |
Qualification | Doctor's degree |
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Print ISBNs | 978-952-64-1441-6 |
Electronic ISBNs | 978-952-64-1442-3 |
Publication status | Published - 2023 |
MoE publication type | G5 Doctoral dissertation (article) |
Keywords
- 5G
- cellular networks
- fault indication
- grid automation
- IEC 61850
- protection
- reliability
- wireless technology