China develops hybrid digital twin for the distribution network

The innovative technology will simulate both the power network and the associated communication network.
Published: Mon 17 Jun 2019

An all-in-one equipment that can achieve real-time cyber-physical simulation of a complex power distribution network with high penetration of renewable resources has been developed by researchers at Southeast University (SEU) in China led by Professor Wei GU.

China has the world’s largest installed capacity of renewable energy, which is still growing at a fast pace to meet the target of 35% renewable energy penetration by 2030, set by China’s National Development & Reform Commission. In some areas in China (e.g. Jinzhai of Anhui Province), high penetration of roof solar PV in rural areas has led to an over-voltage problem, which negatively impacts network stability and solar PV generation. In order to accommodate a large number of renewable generators, appropriate control and protection strategies need to be developed and evaluated for the distribution network. To meet this challenge, the SEU team is developing real-time simulation equipment – the Cyber-Physical Hybrid Real-Time Simulation System (CP-RTSS), funded by the China National Key R&D programme.

SEU researchers proposed a series of new algorithms and integrated solutions, including cluster modelling of distributed renewable resources, adaptive simulation step changing, semi-dynamic matrix sorting and automatic mathematic model switching, which build up a solid foundation for developing CP-RTSS. The up to date CP-RTSS can conduct real-time hardware-in-loop testing for the devices installed on the power distribution network, which gives distribution network operators excellent flexibility to validate the physical electric power devices cost-effectively. Virtual cyber communication simulation platform is also developed and embedded in the CP-RTSS, which can assess various communication protocols and solutions for the distribution network.

 

Compared to conventional power network simulation software and equipment, CP-RTSS is unique and advantageous because of its hybrid simulation capability for both the power network and the associated communication network, and it is able to simulate a large-scale distribution network in real-time with more than 100,000 network nodes or more than 8,000 distributed renewable generator clusters. The CP-RTSS is currently used by Zhejiang Electric Power Research Institute, Anhui Electric Power Research Institute and Yangzhou Power Supply Company as a key research and testing equipment.

“The CP-RTSS significantly reduced the time we spent on setting up the testbed and testing the distribution network devices. When we worked on the islanding micro-grid project in Zhoushan island in 2018, we used CP-RTSS to establish a virtual islanding grid with virtual communication framework in our lab, and tested the devices and control strategies we aimed to adopt on the island in a very short time,” said by Xiaodong Yuan, head of micro-grid research centre, Zhejiang Electric Power Research Institute.

The CP-RTSS has won the golden prize of 47th International Exhibition of Invention Geneva in 2019 and held a number of Chinese and International patents. The research outputs based on CP-RTSS have been published in a number of top peer-reviewed journals including IEEE transactions on Smart Grid, IEEE transactions on Power System and IEEE transactions on Sustainable Energy.

 

General Structure of CP-RTSS