How optical slicing technology is enabling the smarter power grid

China’s State Grid Corporation is working with Huawei’s OSUFlex Optical Transport Network (OTN) technology, currently undergoing standardization with industry partners, as the communications backbone for its smart grid.

After over a century of almost unchanged operation, the power grid is undergoing an evolution which will see it transformed out of current recognition.

The drivers are two-fold. One is the growing availability of smart grid technologies evolving largely from the earlier development of smart meters. The other is the need to drive towards net zero carbon economies with wide-scale renewable energies replacing traditional fossil-fuel generation.

This in turn is bringing new challenges to power grids, many of which are already ageing and unable to cope with the integration of high levels of intermittent sources such as wind and solar.

The situation is particularly acute in countries such as China, where the demand has been growing on the back of the rapid socioeconomic development of the recent years.

For example, in Sichuan province in China’s southwest, total power consumption reached 286.52 billion kWh in 2020, up by 8.7% year-on-year to register the fastest growth among the provinces supplied by the country’s State Grid.

“Power grids face many challenges, including insufficient interactions between resources and load, dependency on redundancy to ensure safety, shrinking balance capacity and lack of efficiency improvement measures,” says an expert from State Grid Sichuan Information & Telecommunication Company’s Operation Inspection Centre.

Power generation and grid companies have taken actions to meet rising demand. But there is still a lack of user participation and policy guidance for power storage, while market mechanisms such as access, transactions and settlement also need to be improved.

To solve these problems, traditional power grids need to transform towards flexible interaction between energy resources, grids, loads and storage. For its approach, State Grid has embarked on a programme to build an ‘energy internet’ by digitalizing its grids.

The energy internet will build a multi-end interconnection and interaction system and involves using technologies like big data, cloud, IoT, mobile, AI and blockchain, along with conducive market factors to improve grid security, operating efficiency and society’s overall energy efficiency.

Image: Huawei

Optical communications

At the core of the utility digital transformation is the communication network and State Grid has selected Huawei’s OSUFlex OTN technology.

OSUFlex is the latest generation of fibre technologies offering features such as a simplified architecture and ubiquitous connectivity.

Liquid OTN inherits the hard pipe of OTN and introduces a service oriented flexible ‘OSUFlex’ container, which makes the bandwidth granularity smaller and more than halves the encapsulation layers. This reduces the footprint by 70% and the power consumption by 50% while the 2Mbit/s bandwidth granularity supports 100-fold more connections

Single site latency is reduced by 70% and 200Gbit/s bandwidth provides full utilization for flexibility and efficiency.

“Traditional technology has hit its bandwidth bottleneck and cannot support the growth of digital services and legacy technologies are being phased out and the power sector needs a new technology that meets the needs of digital power grids,” says the State Grid chief engineer.

“Our research has shown that the new OSUFlex OTN technology is a valid choice for power sector private communications networks.”

In addition to the technological benefits, OSUFlex technology inherits the traditional time-division multiplexing (TDM) technology roadmap and industry direction, while adding synchronous digital hierarchy (SDH) features to OTN technology, thus combining the advantages of SDH and OTN.

With these, OSUFlex can carry various services such as PCM, SDH and packet services in one network and independent pipes can be configured for services of different systems, which improves their security.

As examples, power production requires teleprotection E1 services with strictly 10ms latency, while video surveillance does not have strict latency requirements but does require large bandwidth and scalability.

Communications requirements that OSUFlex will support for State Grid include cloud interconnection, smart power delivery at transmission and distribution levels, Internet of Things connections, smart power consumption communications with consumers and smart operations and maintenance.

State Grid has forecast that by 2025, more than 1 billion devices will be deployed across its grid, collecting over 100TB of data per day.

Thus massive exchange of information is coming as the collection points move closer to the users and the control latency is reduced to real-time.

Image: Huawei

OSUFlex standardization

With its choice of OSUFlex, State Grid also has worked with Huawei, China Telecom, Power Construction of China and Siemens on the standardization of the technology.

The process was formalized in June 2020 with the approval by the IEEE of the P2893 working group under the chairmanship of Hongzhen Yang, which began work in August 2020.

The standard specifies a communication layer, OSUFlex to provide small service channels in optical transport networks. The main features of the OSUflex communication layer are providing massive OSUflex connections to directly carry power services into an optical transport network, enabling the flexible bandwidth and hitless bandwidth adjustment for each OSUflex connection, direct mapping of services into OSUflex with the capabilities of high-bandwidth efficiency, low latency, low latency jitter and high-precision clock synchronization for power system applications.

For more on Huawei’s liquid optical transport technology and its benefits and opportunities in the smart grid, visit the website.