Group 1 - The State Intellectual Property Office of China has published a patent application by Southern Power Grid Scientific Research Institute Co., Ltd. and Guizhou Power Grid Co., Ltd. for a method and device for generating impedance parameter matrices of transformers, with application date on April 2025 [1] - The patent describes a method that calculates the self-impedance of each port of a transformer based on voltage and current when all other ports are open-circuited, and then computes mutual impedance for port pairs, ultimately forming an impedance parameter matrix [1] Group 2 - Southern Power Grid Scientific Research Institute Co., Ltd. was established in 2010 in Guangzhou, focusing on electricity and heat production and supply, with a registered capital of 100 million RMB [2] - The company has invested in 5 enterprises, participated in 5000 bidding projects, and holds 5000 patent records along with 67 trademark records [2] - Guizhou Power Grid Co., Ltd. was founded in 1994 in Guiyang, also focusing on electricity and heat production and supply, with a registered capital of approximately 1.96 billion RMB [2] - Guizhou Power Grid has invested in 39 enterprises, participated in 5000 bidding projects, and holds 5000 patent records along with 6 trademark records [2]