Hangzhou Rizhi Electric Co., Ltd. - Committed to create a technology innovation, green & low-carbon emission, and with social responsibility company.

Home page

2023

220 kV flexible low-frequency transmission project put into operation

On June 30th, China's 220 kV flexible low-frequency transmission project was put into operation in Hangzhou, Zhejiang. This is a flexible low-frequency power transmission project with high voltage level and large transmission capacity in China, which achieves the interconnection and interconnection of the two major load centers in Fuyang and Xiaoshan, Hangzhou. It provides 300000 kilowatts of flexible electricity support for the area where the main venue of the Hangzhou Asian Games is located, meeting the peak electricity demand during the event.

There are multiple Asian Games competition venues distributed in the Fuyang and Xiaoshan regions of Hangzhou. The project aims to build two high-voltage, high-capacity, and low-frequency converter stations on both sides of the Fuchun River. After being put into operation, it is equivalent to establishing a connecting line. The surplus electricity in the two regions can be flexibly interconnected and have millisecond level response capabilities, which can significantly improve the reliability of regional power supply. "Xu Ting, a full-time operator of the Operation and Inspection Department of State Grid Hangzhou Power Supply Company, said that 300000 kilowatts is equivalent to a 100 medium-sized wind turbines generating electricity simultaneously, It can meet the needs of 100000 households using high-power air conditioners with 4 horsepower on scorching summer days.

We have reduced the transmission frequency of the traditional power grid from 50 Hz to 20 Hz. By reducing the transmission frequency, we can reduce 'transmission resistance', thereby improving transmission capacity, distance, and efficiency. In addition to being applied to the interconnection of urban internal power grids, flexible low-frequency transmission technology has significant economic advantages in scenarios such as large-scale offshore wind power transmission and multi island interconnection, compared to existing power frequency AC and DC transmission in the sea area of 70 to 200 kilometers.

At present, there are two main modes of offshore wind power transmission in China: 50Hz power frequency AC transmission and DC transmission. Due to the limitation of active power transmission in submarine cables, the efficiency of power transmission is limited when the power frequency AC transmission exceeds 70 kilometers; However, direct current transmission requires large offshore converter platforms on both sides of the transmission line, which incurs high costs in offshore wind power transmission scenarios within 200 kilometers.

It is understood that the construction of offshore wind power in China has gradually moved towards the COSCO region. It is expected that the scale of offshore wind power development in China will reach 90 million kilowatts by 2030. In order to solve the problem of large capacity transmission in mid to long distance islands and offshore wind farms in the future, in recent years, State Grid Zhejiang Electric Power has been based on technological self-reliance, strengthened original and leading technological breakthroughs, formulated a "step-by-step" plan, and comprehensively mastered the independent core technology of flexible low-frequency transmission. In 2022, it will achieve a demonstration and verification of 35 kV flexible low-frequency transmission technology in Taizhou, This year, the demonstration and verification of 220 kV high-voltage and large-capacity low-frequency transmission equipment was achieved in Hangzhou, filling the technical gap in the field of flexible low-frequency transmission and transformation in the world, including complete design, equipment development, experimental installation, and startup debugging, and occupying the world's technological high ground.

Assist in Asian Games power supply to ensure the operation of China's 220 kV flexible low-frequency transmission project

State Grid Smart Grid Research Institute Lu Zhengang: Flexible Low Frequency AC Transmission Technology and Future Application Prospects for Offshore Wind Power

Related Information

On January 18, the annual technical work meeting was held at the company. Company executives, experts from the academician workstation, and technical backbones attended the meeting, which focused on the technical routes and planning for innovative products in the new year.

Recently, Hangzhou Rizhi signed an agreement with Wulanchabu Ferroalloy Industry Association in Wulanchabu City, Inner Mongolia. As a member of Wulanchabu Ferroalloy Industry Association, Hangzhou Rizhi Company developed and applied three-phase low-frequency flexible digital power supply in Wulanchabu Ferroalloy Production Enterprises. Ulanqab ferroalloy industry association to give specific technical guidance and support.

On March 14, Yang Chuanwei, Secretary -General of the China Electric Stone Industry Association, Jiang Shunping, deputy secretary -general Jiang Shunping, and office director Zhou Bolin and his party, went to Shenmu Xintaihua Electrariac Co., Ltd. to inspect the operation of the 16500kva electrical furnace using a three -phase variable frequency flexible digital power supply.

On January 27, 2024, the first expert committee meeting for the year 2024 was held at Hangzhou Rizhi Electric Co., Ltd. During the conference, experts and scholars from the academician workstation of Zhejiang University and well-known experts in the domestic ferroalloy industry jointly provided guidance on the application of new flexible low-frequency digital power supplies. The picture shows an expert giving a lecture on the theory of submerged arc furnaces.