Communication networks boost digital intelligence for future power system

Communication target network

Construction of a communications infrastructure should be driven by the communication target network. It is essential to address current issues and challenges while also anticipating the needs that will arise over the next five to ten years. In particular, when planning the communication target network, we need to focus on both business scenarios and communication technologies. We must find technologies for scenarios but also scenarios for technologies.

The communication target network in the future power system offers four key features: an intelligent and robust main network, MV integration, LV transparency and full coverage, as shown in Figure 1. An intelligent and robust main network needs to be constructed with consideration for 'optical power transportation' as represented by the 'East Data, West Computing' project, 'electric power transportation' represented by edge computing, and the demands for renewables integration and peak shaving based on spatiotemporal characteristics. 

In addition, in past typhoon emergency response efforts, it was found that the 10kV communication network is the weakest link in power grid communication and is a typical blind spot. Overcoming this requires systematic planning of a communication target network made up of optical fibre and wireless private networks that delivers full wired and wireless coverage capabilities.

Furthermore, given large-scale distributed PV access, charger access, distributed energy storage, user interaction and potential load-side transactions, a systematic approach is needed for 400V LV transparent communication.

At the end of 2023, ETSI released the F5G-A standard. Today, the electric power industry is also planning the electric power communication target network by following the F5G-A roadmap and achieving large-scale deployment. 

In its main network communication, the State Grid Corporation of China has conducted a pilot and commercial use of fgOTN, while EDM in Mozambique has put fgOTN into commercial use. For MV backhaul of power distribution networks, State Grid Shanxi and other power companies have deployed optical fibre networks such as hard-isolated PON. For LV communication, State Grid Shaanxi and other power companies have utilized computing power and IoT connection technologies to achieve 400V transparency.

Main network communication

Consider intelligence-computing collaboration and generational evolution. Dual-plane networking is adopted for all networks to support 99.9999% reliability.

fgOTN is being introduced to seamlessly replace SDH networks, achieving a generational evolution in communication networks. In power grids, there are abundant optical fibre resources, which play a vital role in addressing the core challenges of the future power system. The intelligent development of the electric power industry will demand a hundred times more network connections, ten times more bandwidth and increasingly stringent requirements for network security and reliability. Additionally, the lifecycle of SDH is nearing its end.

The fgOTN standard was officially released by ITU-T in November 2023 and inherits SDH's hard pipe feature while providing tenfold bandwidth.

Network reliability is crucial, and a minimum of 99.9999% reliability is required to ensure deterministic computing connections. For one thing, low latency and highly secure connection technologies should be selected to maintain high reliability. For another, a dual-plane assurance private network must be established to support highly reliable intelligent computing. 

The principle of 'creating new planes before removing old ones' must be followed to ensure that there are always two active planes to deliver high reliability.

MV backhaul

MV communication is the weakest link in power grids and has a direct impact on their balance and stability as well as providing essential assurance in extreme conditions. Optical fibres and spectrum should be utilized as strategic assets to construct a hybrid fibre, wireless communication network, tailored to local conditions, to support 99.99% reliability.

The main network communication can fully utilize existing optical fibre resources. For 10kV backhaul in power distribution networks, coordination between optical fibres and wireless networks is essential. The question is, how can we establish a synergy mechanism between the optical fibre network, wireless private network and wireless public network based on the target network?

Optical fibres support physical isolation, ensuring that services do not interfere with each other. This is the most effective solution for achieving high security and reliability in electric power networks. Fibres are also a critical asset for intelligent and digital development. Where possible, fibre networks should be deployed in all transformer districts, after which differential protection, RTU/FTU backhaul and digital twin services can be further rolled out. 

In the past, digital twins needed to be configured with dedicated rendering hardware. Today, optical fibres and universal tablet addresses can be combined to implement cloud rendering, cloud-edge synergy and ultra-fast delivery.

In the past, power distribution networks had low requirements for communication and digitalization. If a fault occurred, the affected segment would either be switched or isolated from the network. Today, these networks are evolving from unidirectional to bidirectional and from passive to active, becoming more reliant on digitalization and intelligence. This shift necessitates a robust communication infrastructure. In extreme scenarios, the lack of reliable communication can lead to significant losses.

Over time, establishing an electric power wireless private network has become essential for 10kV backhaul. The MV hybrid communication network demands comprehensive planning of both optical fibre and wireless private networks, complemented by wireless public networks when necessary. Additionally, optical fibre dual-route protection, as well as network protection between the optical fibre and wireless private network, between the optical fibre and wireless public network, or between the wireless private network and wireless public network, should be implemented as needed to safeguard the future power system.

LV transparency

Redefine the 400V communication network to provide systematic bottom-layer support for balanced and stable power grids and user satisfaction. Manage the network as the target network to deliver 99.9% reliability.

The challenge of building a future power system lies in power distribution networks, where communication is the key. With the rapid rise of new technologies such as widely distributed renewable energy and electric vehicles, maintaining the balance, stability, and security of distribution networks has become increasingly complex. Issues like reverse power flow and device overloading pose significant challenges. 

To address these, we need both top-down scheduling and bottom-up transformer district autonomy, along with greater transparency at the 400V level to streamline primary and distribution networks and microgrids. High-speed power line carrier (HPLC) technology is already widely used in the 400V transparent communication field, achieving good results.

In the future power system, LV 400V must evolve from merely collecting customer satisfaction and power consumption information to enabling power generation-grid-load-storage interaction. Distributed PV, distributed energy storage, numerous charging piles and user interactions mean that 400V carrier communication should be added to the integrated communication network and managed as part of the target network to achieve over 99.9% reliability, second-level interaction, integrated sensing, communication, computing and topology identification. These capabilities will play a crucial role in systematically addressing 400V challenges.